KR102375323B1 - Doublelip load seal structure for high-pressure hydraulic cylinder - Google Patents

Abstract

The present invention provides the structure of a double-rib load seal mounted in a high-pressure hydraulic cylinder to perform sealing. The double-rib load seal (20) has asymmetric inner and outer surfaces and comprises: an inner bent groove (24); an outer bent groove (26); and a truncated conical groove (28). A main rib (30) having a cross section with an acute angle is provided at the edge where the inner surface and the rear surface (22) of the double-rib load seal (20) cross each other. A sub-rib (35) having a triangular cross section is provided in an area adjacent to a front surface (21) on the inner surface of the double-rib load seal (20). Therefore, the double-rib load seal can be mounted on a high-pressure hydraulic cylinder mounted in various machines and heavy equipment to maintain performance in an environment where high pressure acts for a relatively long time during work, thereby improving operational reliability and durability.

Description

Doublelip load seal structure for high-pressure hydraulic cylinder

The present invention relates to a hydraulic cylinder for high pressure, and more particularly, to a double lip rod seal structure of a hydraulic cylinder for high pressure that is mounted on various machines and heavy equipment to perform a pressurization or crushing function.

In general, hydraulic cylinders mounted on various machines and heavy equipment are used to pressurize an object with a large load or crush it with a large impact using a hydraulic source. The hydraulic cylinder is a structure accommodating a piston reciprocating up and down by hydraulic pressure inside a housing, and is operated by pressure oil supplied to upper and lower ends of the piston and a chamber formed in the middle through a valve. The double lip rod seal installed on the hydraulic cylinder is one of the important parts that determine the operation reliability and durability of the hydraulic cylinder.

As prior art documents that can be referred to in relation to the double lip rod seal of a hydraulic cylinder, Korean Patent Registration No. 0993570 (Prior Document 1), Korean Patent Publication No. 2073973 (Prior Document 2), and the like are known.

In Prior Document 1, an outer circumferential vertical surface is formed upward, a slope cut inwardly inclined at the end of the outer vertical surface, a horizontal upper surface is formed at the end of the slope, and a vertical cut surface is formed downward at the end of the horizontal upper surface, and the end thereof The incision groove is formed concave inward. Accordingly, the effect of extending the sealing life and replacement period of the double lip rod seal and improving the airtightness is expected.

Prior Document 2 discloses that in the double lip rod seal for a cylinder made of an X-ring to be fitted into the fastening groove, an annular seating protrusion is further formed in the fastening groove, and the X-ring has an annular seating groove to be fitted into the seating protrusion of the fastening groove. It is further formed, and an annular gripping protrusion is further formed in the X-reel to be replaced. Accordingly, the effect of maximizing the replacement interval of the double lip rod seal is expected by improving the supporting force and restoring force.

However, given the fact that the operating pressure is gradually increasing due to the development of machinery and equipment, it is insufficient to maintain the performance for a long time at high pressure, showing room for improvement.

Korean Patent Publication No. 0993570 "Double lip rod seal structure for hydraulic breaker" (published on April 29, 2010) Korean Patent Publication No. 2073973 "Double lip rod seal for cylinder with X-ring fastening structure" (published date: 2020.03.02.)

An object of the present invention for improving the conventional problems as described above is a high pressure hydraulic cylinder that can maintain performance in an environment where high pressure acts for a relatively long time while being mounted on a hydraulic cylinder mounted on various machines and heavy equipment to perform work. It is intended to provide a double lip rod seal structure.

In order to achieve the above object, the present invention provides a double lip rod seal structure mounted and sealed in a high-pressure hydraulic cylinder: the double lip rod seal is formed with asymmetric inner and outer surfaces and includes an inner curved groove, an outer curved groove, and a truncated cone It is characterized in that it has a groove, and a main rib of acute angle cross section is provided at a corner where the inner surface and the rear surface of the double lip rod seal intersect, and a sub-rib of a triangular cross section is provided in an area adjacent to the front surface on the inner surface of the double lip rod seal. do it with

As a detailed configuration of the present invention, the double lip rod seal has a hardness of 93shore A, a tensile strength of 55Mpa, an elongation of 520%, a vicat softening point of 175°C, and a compression set. ) It is characterized by using polyurethane with physical properties of 38% (100℃, 70 hours).

As a detailed configuration of the present invention, the sub-rib is characterized in that it protrudes to form a diameter smaller than the inner bending groove and larger than the main rib.

As a modified example of the present invention, the double lip rod seal further comprises a reinforcing ring having relatively high elasticity and cushioning resistance on the truncated cone groove.

As a modified example of the present invention, the double lip rod seal further includes an auxiliary ring having relatively high elasticity and high wear resistance on the sub-rib.

As described above, according to the present invention, since it is mounted on a high-pressure hydraulic cylinder mounted on various machines and heavy equipment to perform work, it maintains performance in an environment where high pressure acts for a relatively long time, thereby improving operational reliability and durability.

1 is a schematic diagram showing an application example of a double lip rod seal according to the present invention;
Figure 2 is a block diagram showing the double lip rod seal separated according to the present invention
3 is a block diagram showing the main part of the double lip rod seal according to the present invention;
4 is a block diagram showing a modified example of the double lip rod seal according to the present invention;

[Example]

Hereinafter, an embodiment of the present invention will be described in detail based on the accompanying drawings.

The present invention proposes with respect to a double lip rod seal structure that is mounted and sealed in a high pressure hydraulic cylinder. It targets hydraulic cylinders mounted on various machines and heavy equipment operated with high load (torque), but is not necessarily limited thereto.

Referring to FIG. 1 , a housing 11 , a bearing 13 , a piston 15 , a rod 17 , a double lip rod seal 20 and the like constituting the hydraulic cylinder 10 are shown. The housing 11 is formed in a cylindrical shape and has a port through which hydraulic oil enters and exits. The piston 15 is accommodated in the housing 11 and transmits hydraulic force to the outside through the rod 17 . The bearing 13 is fixed to the end of the housing 11 to slidably support the rod 17 . The double lip rod seal 20 is installed on the outer inner surface of the bearing 13 so as to be in close contact with the rod 17 .

Meanwhile, the present invention is not limited to the double lip rod seal 20 installed on the bearing 13 , but is not limited thereto, and may be applied to the piston 15 .

According to the present invention, the double lip rod seal 20 has an asymmetric inner and outer surface and has an inner curved groove 24 , an outer surface curved groove 26 , and a truncated conical groove 28 .

1 and 2, the front 21, the rear 22, the inner bending groove 24, the outer surface bending groove 26, the truncated conical groove 28, etc. constituting the double lip rod seal 20 appears. The front surface 21 is a portion adjacent to the direction in which the high pressure of the hydraulic oil acts, and the rear surface 22 is a portion opposite to the front surface 21 . The inner bending groove 24 is a portion bent at an obtuse angle on the inner surface between the front surface 21 and the rear surface 22 , and the outer surface bending groove 26 is a portion bent at an obtuse angle from the opposite side to the inner bending groove 24 . The frusto-conical groove 28 is disposed on the rear surface 22 and is in the form of a groove of a U-shaped cross-section that is widened. The rear surface 22 is divided into two by the frustoconical groove 28 while maintaining the height difference. Of course, the corners of the front 21 , the rear 22 , the inner bending groove 24 , the outer surface bending groove 26 , and the frustoconical groove 28 have a round of about 1 to 2 mm. The double lip rod seal 20 having such a structure closely supports the piston 15 in the hydraulic cylinder 10 .

As a detailed configuration of the present invention, the double lip rod seal 20 has a hardness of 93shore A, a tensile strength of 55Mpa, an elongation of 520%, a softening point of 175°C, and a permanent compression set. (Compression set) It is characterized by using polyurethane with physical properties of 38% (100℃, 70 hours).

As shown in FIG. 1 , 4 to 10 types of seals are mounted on the hydraulic cylinder 10 according to the standard (capacity). The part that plays a key role in preventing the high pressure of the hydraulic oil is the double lip rod seal 20 . The double lip rod seal 20 uses a polyurethane material because fluid friction with the inner wall of the housing 11 is made while blocking high pressure. In general, in the case of the hydraulic cylinder 10 for medium and low pressure, the physical properties of the double lip rod seal are in the range of hardness 93~94shore A, tensile strength 42~52Mpa, elongation 440~500%, and softening point 130~170℃.

On the other hand, the main material of the double lip rod seal 20 is polyurethane, but at least partially silicone rubber and thermoplastic elastomer (TPE) may be selectively mixed.

In addition, according to the present invention, the double lip rod seal 20 has a structure including the main rib 30 having an acute angle cross-section at the corner where the inner surface and the rear surface 22 intersect.

2 and 3 , the main rib 30 formed between the inner surface and the rear surface 22 of the double lip rod seal 20 is shown. The main rib 30 protrudes inward in the central axis direction in order to block the pressure of the hydraulic oil. The main rib 30 has a substantially triangular cross-sectional shape and is elastically closely attached to the piston 15 to allow sliding motion. The double lip rod seal 20 has a large elastic deformation due to the connection of the frusto-conical groove 28 and the main rib 30 in the rear 22 than in the front 21 .

In addition, according to the present invention, the inner surface of the double lip rod seal 20 has a structure including the sub-rib 35 having a triangular cross section in an area adjacent to the front surface 21 .

2 and 3 , the sub-rib 35 formed from the inner surface of the double lip rod seal 20 toward the front surface 21 is shown. In the case of the hydraulic cylinder 10 for high pressure, it is preferable to use the sub-ribs 35 in addition to the main ribs 30 . The sub-rib 35 protrudes from the inner surface in a substantially triangular cross-sectional shape. The sub-rib (35) blocks the hydraulic oil pressure by 30-40%, and the main rib (30) blocks 60-70% of the hydraulic pressure. Due to the double sealing structure by the main rib 30 and the sub-rib 35, it is possible to use the hydraulic cylinder 10 at a high pressure of about 20% or more compared to the prior art, and the lifespan is increased in proportion thereto.

As a detailed configuration of the present invention, the sub-rib 35 is smaller than the inner curved groove 24 and protrudes to form a diameter D2 larger than that of the main rib 30 .

In FIG. 3 , the diameter D2 of the sub-rib 35 is larger than the diameter D1 of the main rib 30 . The diameter D1 of the main rib 30 and the diameter D2 of the sub-rib 35 are smaller than the diameter of the inner bending groove 24 . The main rib 30 is in close contact with the piston 15, but since it is linked with the frusto-conical groove 28 and the elastic deformation is large, the sharing of the hydraulic oil pressure between the main rib 30 and the sub-rib 35 is maintained in the above-described range. do. When only the main rib 30 is used without the sub-rib 35 or the pressure sharing between the main rib 30 and the sub-rib 35 is inadequate, frictional heat is dissipated and wear proceeds rapidly.

On the other hand, the main rib 30 and the sub-rib 35 is also preferably to form a round of about 1-2 mm in the corner portion.

As a modified example of the present invention, the double lip rod seal 20 is characterized in that it further comprises a reinforcing ring 40 having relatively high elasticity and cushioning resistance on the frustoconical groove 28 .

Referring to FIG. 4 , the reinforcing ring 40 is mounted on the frustoconical groove 28 of the double lip rod seal 20 . The reinforcing ring 40 is preferably made of a high elastic material to reinforce the elasticity of the double lip rod seal 20 . In addition, it is also necessary for the double lip rod seal 20 to withstand the impact in response to a large pressure fluctuation of the hydraulic oil according to the work contents of the hydraulic cylinder 10 . The reinforcing ring 40 is preferably made of metal, but engineering plastics may also be used. The reinforcing ring 40 is integrated with the double lip rod seal 20 by insert molding, and the concave-convex portion 42 is formed on the surface of the reinforcing ring 40 to increase the bonding force.

As a modified example of the present invention, the double lip rod seal 20 further includes an auxiliary ring 45 having relatively high elasticity and high wear resistance on the sub-rib 35 .

In FIG. 4 , the auxiliary ring 45 is mounted on the sub rib 35 of the double lip rod seal 20 . The auxiliary ring 45 is preferably made of a material having relatively high elasticity to reinforce the elasticity of the double lip rod seal 20 . In addition, it is also necessary to increase the wear resistance of the double lip rod seal 20 according to the operation contents of the hydraulic cylinder 10 . The auxiliary ring 45 is preferably made of metal, but engineering plastics may also be used. The auxiliary ring 45 may be limited to a portion of the sub-rib 35 , or may be separately added at a position spaced apart from the sub-rib 35 .

The present invention is not limited to the described embodiments, and it is apparent to those skilled in the art that various modifications and variations can be made without departing from the spirit and scope of the present invention. Accordingly, it should be said that such variations or modifications fall within the scope of the claims of the present invention.

10: hydraulic cylinder 11: housing
13: bearing 15: piston
17: rod 20: double lip rod seal
21: front 21: rear
24: inner groove 26: outer groove
28: U-shaped groove 30: main rib
35: sub rib 40: elastic ring
42: concavo-convex 45: reinforcing ring

Claims (5)

In the structure of the double lip rod seal that is mounted and sealed in the hydraulic cylinder for high pressure:
The double lip rod seal 20 is formed with asymmetric inner and outer surfaces and has an inner curved groove 24, an outer curved groove 26, and a truncated conical groove 28,
A main rib 30 having an acute angle cross section is provided at the corner where the inner surface and the rear surface 22 of the double lip rod seal 20 intersect,
A sub-rib 35 of a triangular cross section is provided in an area adjacent to the front surface 21 on the inner surface of the double lip rod seal 20,
The rear surface 22 maintains a height difference while facing in a parallel state from the opposite side to the front surface 21,
The sub-rib 35 protrudes to form a diameter D2 smaller than the inner bending groove 24 and larger than the main rib 30,
The double lip rod seal 20 further includes a reinforcing ring 40 having a concave-convex portion 42 while having higher elasticity and cushioning resistance than that on the frusto-conical groove 28,
The double lip rod seal structure of a hydraulic cylinder for high pressure, characterized in that the double lip rod seal (20) further includes an auxiliary ring (45) having higher elasticity and wear resistance than that on the sub rib (35).
The method according to claim 1,
The double lip rod seal 20 had a hardness of 93shore A, a tensile strength of 55Mpa, an elongation of 520%, a vicat softening point of 175°C, and a compression set of 38% ( Double lip rod seal structure of hydraulic cylinder for high pressure, characterized by using polyurethane with physical properties of 100℃, 70 hours).
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