KR20060033426A - Sealing structure for hydraulic cylinder - Google Patents

Abstract

The present invention relates to a sealing structure of a hydraulic cylinder for installing a foreign matter adsorption unit for adsorbing a hard foreign matter contained in the pressurized oil so that foreign matter does not flow into the sealing unit, thereby improving durability and maintaining the hydraulic cylinder operation smoothly.

The sealing structure of the hydraulic cylinder according to the present invention is installed between the tube and the rod of the hydraulic cylinder to seal the hydraulic oil in the tube, the head cover is provided at one end of the tube to contact the outer surface of the rod and the head cover in contact with the rod It is installed on the inner surface sealing portion between the tube and the rod and at least one foreign matter adsorption portion is installed on the head cover to adsorb foreign substances contained in the pressure oil so as not to enter the sealing portion.

Hydraulic cylinder, sealing, pollution prevention, foreign substance, diesel effect, piston, rod

Description

Sealing structure for hydraulic cylinder

1 is a side cross-sectional view of a hydraulic cylinder according to the prior art,

Figure 2a is an enlarged detail view of the rod sealing portion of the hydraulic cylinder shown in FIG.

Figure 2b is an enlarged detail view of the piston seal of the hydraulic cylinder shown in Figure 1,

3 is a side cross-sectional view of a hydraulic cylinder with a sealing structure according to a first embodiment of the present invention;

4 is an enlarged partial view of a sealing structure of the hydraulic cylinder shown in FIG.

5 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a second embodiment of the present invention;

6 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a third embodiment of the present invention;

7 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a fourth embodiment of the present invention;

8 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a fifth embodiment of the present invention;

9 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a sixth embodiment of the present invention;

10 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a seventh embodiment of the present invention;

11 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to an eighth embodiment of the present invention;

12 is a partially enlarged view of a sealing structure of the hydraulic cylinder according to the ninth embodiment of the present invention.

* Explanation of symbols for main parts of the drawings

1: hydraulic cylinder 15: sealing structure

2: tube 16: large chamber

3: load 17: small chamber

4: head cover 18: piston

5: sealing part 21: magnet adsorption plate

6: wiper seal 31: magnet adsorption ring

7: load chamber 9,9b: wear ring

8: buffer chamber 10,20,30,40,40b: foreign material adsorption unit

The present invention relates to a sealing structure of a hydraulic cylinder, and more particularly, a foreign material adsorption unit for adsorbing a hard foreign matter contained in the pressure oil is installed, so that foreign matter does not flow into the sealing unit, so that durability is improved and hydraulic cylinder operation is smoothly maintained. It relates to a sealing structure of the hydraulic cylinder.

1 is a side cross-sectional view of a hydraulic cylinder according to the prior art, FIG. 2A is an enlarged detail view of a rod seal portion of the hydraulic cylinder shown in FIG. 1, and FIG. 2B is an enlarged detail view of a piston seal portion of the hydraulic cylinder shown in FIG. 1.

Hydraulic cylinder 100 used for heavy construction equipment such as excavators, as shown, is made of a piston 112 and the rod 103 and the like reciprocating linearly by the hydraulic pressure in the tube (102).

Since the hydraulic oil is supplied to the tube 102 and the pressure by the hydraulic oil is formed therein, the piston 112 moves to the left and right in the tube 102 by the pressure of the hydraulic oil. Outside the piston 112, a piston sealing portion 120 made of a piston chamber 121 and a wear ring 122 is installed to contact the inner surface of the tube 102, and the oil pressure on the left and right sides of the piston 112 is It functions to seal the tube 102 so as not to pass through each other.

A head cover 104 is mounted on the left side of the tube 102, and a rod sealing part 130 is mounted on the head cover 104 to prevent leakage of oil from the contact portion between the rod 103 and the tube 102. It functions to seal to prevent foreign substances from entering.

The cover end 140 is connected to the tube 102 by welding to form a space where the ends of the rod 103 contact when the rod 103 is contracted into the tube 102, and the hydraulic cylinder 100. To the work tool.

When the hydraulic oil discharged from the hydraulic pump flows into the large chamber 117 of the hydraulic cylinder 100 through the switching valve, the piston 112 is moved to the left side so that the rod 103 is extended out of the tube 102. When the oil flows into the small chamber 118, the piston 112 moves to the right, and the rod 103 is contracted into the tube 102. As such, even when the linear reciprocating motion of the piston 112 and the rod 103 proceeds, the piston sealing part 120 is in intimate contact with the tube 102, so that a seal is formed between the small chamber 118 and the large chamber 117. The oil pressures on the left and right sides of the piston 112 do not communicate with each other.

The piston sealing part 120 includes a piston chamber 121, a wear ring 122, and a pollution prevention chamber 123. The piston chamber 121 serves to seal the pressurized oil, the contamination prevention chamber 123 serves to prevent foreign matter from entering, and the wear ring 122 serves as a guide to guide the linear reciprocating motion of the piston.

The rod sealing unit 130 is in contact with the outer surface of the rod 103, the wiper seal (131) to prevent foreign substances from entering, the load chamber 132 to seal the pressure oil, and the buffer It consists of a thread 133.

The hydraulic oil used in the hydraulic system of the equipment includes foreign substances caused by mechanical wear of other parts of the equipment and foreign substances existing in the flow path for supplying the hydraulic oil.The foreign substances are transported together. When attached to the 130, the rod sealing portion 130 may be directly damaged, or foreign matter attached to the rod sealing portion 130 may cause a problem of damaging the surface of the rod and the tube.

In general, the piston seal portion 120 of the hydraulic cylinder 100 according to the prior art described above is provided with a pollution prevention chamber 123 to prevent such hard foreign matter from entering into the seal portion, but the rod seal portion 130 ), There is a problem that the rod sealing unit 130 and the rod 103 and the tube 102 due to the inflow of foreign matter in the pressure oil is not installed in the pollution prevention room.

On the other hand, when air is mixed into the hydraulic cylinder 100, when the rod 103 is operated to the end stroke, the oil pressure is adiabaticly compressed and a diesel effect phenomenon occurs in which an internal explosion occurs. The rod sealing part 130 The load chamber 132 is damaged by being directly affected by such a diesel effect, there is a problem that its life is shortened.

Therefore, there is an urgent need for technical improvement of the rod sealing part 130 to prevent the hard foreign matters contained in the pressure oil from being attached to the rod sealing part 130 and not to shorten the life due to the diesel effect.

The present invention has been made to solve the problems described above, an object of the present invention is to improve the durability of the hydraulic cylinder by improving the sealing structure of the hydraulic cylinder to maintain a smooth operation of the hydraulic cylinder.

Another object of the present invention is to provide a sealing structure of the hydraulic cylinder to improve the durability of the sealing portion by preventing the hard foreign matter contained in the pressure oil supplied to the hydraulic cylinder does not flow into the sealing portion and is not affected by the diesel effect phenomenon. It is.

In order to achieve the above object, the present invention provides a sealing structure of a hydraulic cylinder provided with a foreign matter adsorption unit for adsorbing a hard foreign matter contained in the pressure oil.

The sealing structure of the hydraulic cylinder according to the present invention is installed between the tube and the rod of the hydraulic cylinder to seal the hydraulic oil in the tube, the head cover is provided at one end of the tube to contact the outer surface of the rod and the head cover in contact with the rod It is installed on the inner surface sealing portion between the tube and the rod and at least one foreign matter adsorption portion is installed on the head cover to adsorb foreign substances contained in the pressure oil so as not to enter the sealing portion.

The sealing part is provided in front of the head cover to prevent the inflow of foreign substances into the tube, a wiper seal installed at the rear of the wiper seal to seal the pressure oil in the tube from leaking to the outside, and installed at the rear of the load chamber in the tube. It is preferable to include a buffer chamber for absorbing the formed high pressure, and a wear ring provided behind the buffer chamber to support the load of the rod.

Here, preferably, the foreign matter adsorption unit may be installed at the rear of the wear ring on the inner side of the head cover, or may be installed between each seal on the inner side of the head cover.

In addition, preferably, the foreign matter adsorption unit may be installed at each position between the wiper chamber and the rod chamber of the inner side of the head cover and at the position behind the wear ring.

Preferably, the foreign material adsorption unit may be integrally combined with the wear ring.

More preferably, the foreign matter adsorption unit may be formed of a magnet adsorption plate installed at an inner edge of the rear side of the head cover in contact with the rod outer surface.

In addition, the foreign matter adsorption unit may be made of a magnet adsorption ring installed on the inner surface of the head cover.

Hereinafter, with reference to the preferred embodiments of the accompanying drawings, looks at the configuration and operation of the hydraulic cylinder sealing structure according to the present invention in more detail.

3 is a side cross-sectional view of a hydraulic cylinder in which a sealing structure according to the first embodiment of the present invention is installed.

The hydraulic cylinder 1 in which the sealing structure 15 according to the first embodiment of the present invention is installed is a general hydraulic cylinder used in construction equipment such as an excavator, and includes a hollow tube 2 through which pressure oil flows in and out. ), A piston 18 which is installed to move left and right by the pressure of the pressure oil formed in the tube 2, and connected to the piston 18 to extend out of the tube 2 or to expand inside the tube 2 And a rod 3 for linear reciprocating motion. The inside of the tube 2 is divided into a large chamber 16 on the right side and a small chamber 17 on the left side by the piston 18.

The sealing structure 15 of the hydraulic cylinder 1 according to the first embodiment of the present invention is provided between the tube 2 and the rod 3 to seal the pressure oil in the tube 2.

4 is a partially enlarged view of a sealing structure of the hydraulic cylinder shown in FIG. 3. The sealing structure 15 includes a head cover 4, a sealing part 5 provided on the inner surface of the head cover 4, and a foreign matter adsorption part 10. The head cover 4 is installed at one end of the tube 2, and in contact with the outer surface of the rod 3 to guide the rod 3 to linearly reciprocate in the longitudinal direction of the tube 2. It acts as a stopper to seal the tube (2).

A sealing part 5 is installed on the inner surface of the head cover 4 to seal between the tube 2 and the rod 3 so that the pressure oil in the tube 2 does not flow out, and external foreign matter is introduced into the tube 2. ) It does not flow into the inside.

The foreign matter adsorption part 10 is installed on the head cover 4 to adsorb the hard foreign matter contained in the pressure oil so that the foreign matter adsorption part 10 does not flow into the sealing part 5 so as to prevent the foreign matter adsorption part 10 from each seal and rod of the sealing part 5. 3) It has a function to protect.

The sealing part 5 is a wiper chamber 6 which is provided in turn on the inner surface of the head cover 4 so as to contact the outer surface of the rod 3, the rod chamber 7, the buffer chamber 8, the wear ring (9) is made.

The function of each seal of the sealing part 5 is as follows. The wiper chamber 6 is installed in front of the head cover 4 to prevent foreign substances from entering the tube 2, and the rod chamber 7 is installed at the rear of the wiper chamber 6 so that the tube 2 It functions to seal the pressure oil therein so that it does not leak to the outside, and the buffer chamber 8 is installed at the rear of the load chamber 7 to absorb the high pressure formed in the tube 2. The wear ring 9 also functions to support the load of the rod 3.

The foreign material adsorption unit 10 is preferably installed behind the wear ring 9 on the inner surface of the head cover 4. That is, the foreign substance adsorption | suction part 10 is provided in the position before the pressure oil in the small chamber 17 of the tube 2 reaches the sealing part 5. The foreign material adsorption unit 10 is preferably made of a single material or compound, such as rubber, urethane, glass fiber, PTFE, graphite, bronze.

Among the foreign matters attached to the surface of the rod 3, the foreign matter of soft material does not flow into the sealing part 5 side by the foreign matter adsorption part 10 as the rod 3 moves with respect to the tube 2, and with the hydraulic oil. It is discharged out of the tube (2). When a hard foreign matter is attached to the surface of the rod 3, since the hardness of the foreign matter adsorption part 10 is weaker than the foreign matter, particles are penetrated into the foreign matter adsorption part 10 and adsorbed to the foreign matter adsorption part 10 so as to be sealed. It does not flow into the part 5 side.

Even when the rod 3 is operated to the end stroke with the air mixed inside the hydraulic cylinder 1, and the pressure oil is adiabaticly compressed and exploded, the foreign matter adsorption part before the impact of the explosion is transmitted to the sealing part 5 side. Since 10 absorbs shock primarily, each seal of the sealing part 5 is not damaged.

5 is a sealing structure of a hydraulic cylinder according to a second embodiment of the present invention. According to the second embodiment, the structure in which the foreign matter adsorption unit 10 is installed behind the wear ring 9 on the inner side of the head cover 4 is the same as that of the first embodiment, but the foreign matter adsorption unit 10 is the buffer chamber. (8) The position where the position is installed slightly on the basis of the wear ring 9 is different from the rear side.

6 is a sealing structure of the hydraulic cylinder according to the third embodiment of the present invention, Figure 7 is a sealing structure of the hydraulic cylinder according to the fourth embodiment of the present invention, Figure 8 is a hydraulic cylinder according to the fifth embodiment of the present invention 9 shows a sealing structure of a hydraulic cylinder according to a sixth embodiment of the present invention.

According to the third embodiment, the foreign matter adsorption unit 10 is changed to be installed between the wear ring 9 and the buffer chamber 8. The fourth embodiment is a modified example in which the foreign matter adsorption unit 10 is installed between the buffer chamber 8 and the rod chamber 7 on the inner side of the head cover 4, and the fifth embodiment is the foreign matter adsorption unit 10. Is an example modified so as to be installed between the wiper chamber 6 and the rod chamber 7 on the inner side of the head cover 4. As in the third to fifth embodiments, the foreign material adsorption unit 10 is installed between the respective chambers in the sealing unit 5 alone to assist the wiper chamber 6 so that external foreign substances do not enter the sealing unit 5. ) Or rod 3 can be prevented from being damaged.

As in the third to fifth embodiments, one foreign matter adsorption unit 10 may be installed and used independently between the seals of each sealing unit, but as in the sixth embodiment, one of the two foreign matter adsorption units 10 may be used. May be installed between the wiper chamber 6 and the rod chamber 7, and the other may be installed and used behind the wear ring 9. According to the sixth embodiment, the foreign matter adsorption unit 10 prevents foreign substances from flowing into and out of the tube 2, respectively.

FIG. 10 is a partially enlarged view of a sealing structure of a hydraulic cylinder according to a seventh embodiment of the present invention, wherein the foreign matter adsorption portions 40 and 40b of the sealing structure of the seventh embodiment support a load of the rod 3. , 9b) to be integrally coupled to each other.

The wear rings 9 and 9b are cylindrical members for supporting the load of the rod 3 made of metal or non-metallic material. The foreign material adsorption portions 40 and 40b are also made of a cylindrical shape, and the wear rings 9 and 9 are formed by a bonding method or the like. 9b) integrally coupled.

Thus, by applying the foreign matter adsorption portions 40 and 40b integrally coupled with the wear rings 9 and 9b to the sealing structure, a more compact seal portion 5 can be configured, and the wear rings 9 and 9b are loaded ( In addition to supporting the load of 3) it can serve to adsorb foreign substances.

11 is a sealing structure of the hydraulic cylinder according to the eighth embodiment of the present invention, Figure 12 shows a sealing structure of the hydraulic cylinder according to the ninth embodiment of the present invention.

According to the eighth embodiment, the foreign matter adsorption unit 20 is preferably made of a magnet adsorption plate 21 installed on the inner edge of the rear side of the head cover 4 in contact with the outer surface of the rod 3. The magnet adsorption plate 21 may be provided by a method of magnetizing a part of the head cover 4 or attaching a magnet plate material.

As illustrated, when the plate-shaped magnetic material foreign matter adsorption portion 20 is installed at the rear of the head cover 4, when the rod 3 linearly reciprocates with respect to the tube 2, the hard foreign matter of the metal material contained in the hydraulic oil is removed. Adsorbed by the foreign matter adsorption unit 20 and the adsorbed state is maintained continuously does not flow into the sealing unit (5).

According to the ninth embodiment, the foreign matter adsorption part 30 preferably includes a magnet adsorption ring 31 installed on the inner surface of the head cover 4. Since a space portion for accommodating the foreign matter adsorbed is formed inside the magnet adsorption ring 31, even if the rod 3 continues to reciprocate linearly with respect to the tube 2, the hard foreign matter contained in the hydraulic oil is sealed. It does not flow into (5), but is kept in the state adsorbed inside the magnet adsorption ring 31.

The magnet adsorption ring 31 is installed on the inner side of the head cover 4 by magnetizing a part of the inner side of the head cover 4 or by making a ring shaped with a magnet to mount the inner side of the head cover 4. Can be used.

In addition, instead of using a permanent magnet in the magnet adsorption plate 21 and the magnet adsorption ring 31 described above, a magnet is manufactured by using a general metal material, and connected to an electric supply device to add a current to form a magnetic electromagnet. You can also use the method.

As the present invention can be variously modified by those skilled in the art without departing from the scope of the claims claimed in the claims, the technical protection scope of the present invention is a specific preferred embodiment described above It is not limited to.

According to the sealing structure of the hydraulic cylinder of the present invention as described above, since the hard foreign matter included in the pressure oil supplied to the hydraulic cylinder does not flow into the sealing portion, the durability is improved and the hydraulic cylinder operation is smoothly maintained.

In addition, since the impact of the diesel effect is absorbed by the foreign matter adsorption unit, the durability of the sealing unit is improved.

Claims (8)

In the sealing structure of the hydraulic cylinder which is installed between the tube and the rod of the hydraulic cylinder to seal the hydraulic oil in the tube: A head cover installed at one end of the tube to be in contact with the rod outer surface; A sealing part installed on an inner surface of the head cover in contact with the rod to seal the tube and the rod; And And at least one foreign matter adsorption unit installed on the head cover to absorb foreign substances contained in the pressure oil so as not to flow into the sealing unit. The method of claim 1, The sealing unit is provided in front of the head cover and the wiper chamber to prevent foreign matter from entering into the tube, the rod chamber is installed behind the wiper chamber to seal the pressure oil in the tube to the outside, and the rod chamber And a wear chamber installed at the rear to absorb the high pressure formed in the tube, and a wear ring installed at the rear of the buffer chamber to support the load of the rod. The method of claim 2, The foreign material adsorption unit is a sealing structure of the hydraulic cylinder, characterized in that installed in the rear of the wear ring on the inner surface of the head cover. The method of claim 2, The foreign material adsorption unit is a sealing structure of the hydraulic cylinder, characterized in that provided between each seal of the inner surface of the head cover. The method of claim 2, And the foreign material adsorption unit is installed one each at a position between the wiper chamber and the rod chamber on the inner surface of the head cover and at a position behind the wear ring. The method of claim 2, Sealing structure of the hydraulic cylinder, characterized in that the foreign matter adsorption unit is integrally coupled with the wear ring. The method according to claim 1 or 2, The foreign material adsorption unit is a sealing structure of a hydraulic cylinder, characterized in that made of a magnet adsorption plate is installed on the inner edge of the back of the head cover in contact with the rod outer surface. The method according to claim 1 or 2, The foreign material adsorption unit is a sealing structure of a hydraulic cylinder, characterized in that made of a magnet adsorption ring installed on the inner surface of the head cover.

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