KR20180043749A - The hydraulic breaker sealing structure - Google Patents

Abstract

The present invention relates to a sealing structure of a hydraulic breaker. An objective of the present invention is to reduce inevitable heat generation between a piston and a seal during crushing work of a hydraulic breaker to prevent or delay hardening of a sealing material and prevent separated particles from flowing into a cylinder if the particles are separated from the sealing material by hardening of the sealing material. The present invention relates to a hydraulic breaker which strikes a chisel by kinetic energy created by a reciprocation motion of an ascent and a descent of a piston in a cylinder and crushes an object to be struck by impact energy converted by the chisel. The sealing structure of the hydraulic breaker is sequentially installed between an outer circumferential surface of a lower circumference of a piston and an inner circumferential surface of a cylinder to include a plurality of sealing materials. The sealing structure comprises: a buffer ring assembly unit (15) formed on the inner circumferential surface of the cylinder (3a); and a buffer ring (14) which is inserted and installed on the buffer ring assembly unit (15), and firstly seals the outer circumferential surface of the lower circumference of the piston (3).

Description

SEALING STRUCTURE OF HYDRAULIC BREAKER SEALING STRUCTURE

The present invention relates to a hydraulic breaker, and more particularly, to a hydraulic breaker that reduces heat generated inevitably generated between a piston and a seal during a crushing operation of a hydraulic breaker to prevent or delay the hardening of the seal, To prevent the escaped particles from flowing into the cylinder. The present invention relates to a sealing structure of a hydraulic breaker.

The hydraulic breaker is a device that transmits kinetic energy generated by up and down reciprocating motion of a piston to a chisel to crush a pit explosion.

1 is a structural view for explaining the operation principle of a general hydraulic breaker. When hydraulic fluid discharged from a pump 1 is supplied to a cylinder chamber 2 through a second flow path F2, the pressure of the cylinder chamber 2 rises And the rising stroke of the piston 3 is started. At this time, a high pressure is formed by the operating oil supplied from the pump 1 and the valve switching chamber 5 is connected to the cylinder low pressure chamber 7 connected to the working oil tank 6 by the seventh flow path F7. So that a low pressure is formed. Accordingly, the working oil in the cylinder-like chamber 9 is discharged to the working oil tank 6 through the third flow path F3 and the fifth flow path F5 connected to the working oil tank 6, so that the low pressure of the cylinder-like chamber 9 is maintained . Thereafter, when the piston 3 continues to rise and the lower pressure receiving surface (lower surface of the lower large diameter portion PL) of the piston reaches the cylinder switching chamber 8, the cylinder chamber 2 connected to the pump 1 is returned to the cylinder switching chamber 8 and communicates with the valve switching chamber 5 through the seventh flow path F7 and the valve switching chamber 5 is formed with the same high pressure as the valve opening 4. At this time, the valve is switched so that the first flow path F1 and the third flow path F3 are communicated with each other, and the cylinder chamber 9 is connected to the cylinder chamber 2 ) Is formed. At this time, since the area of the upper hydraulic pressure surface of the piston (the upper surface of the upper large-diameter portion PU) is larger than the area of the lower hydraulic pressure surface of the piston, the rising stroke of the piston 3 is stopped and the descending stroke starts. At this time, the piston 3 has potential energy in the cylinder conversion chamber 8 where the descending stroke starts. The potential energy of the piston 3 is converted into kinetic energy until the piston 3 starts to descend and immediately before the piston 3 comes into contact with the chisel 10, The kinetic energy is converted into impact energy, that is, a striking force, which is transmitted to the pit boat through the chisel 10. At this time, when the upper surface of the lower large-diameter portion PL of the piston 3 passes the cylinder conversion chamber 8, the valve switching chamber 5 is connected to the cylinder low-pressure chamber 7 connected to the tank 6 by the seventh channel F7. And the third flow path F3 is communicated with the fifth flow path F5 connected to the tank 6 so that the pressure of the cylinder lowering chamber 9 is lowered and the piston 3 is returned to the lower flow path F2. .

The hydraulic breaker transmits the impact energy to the impact material by crushing the pit explosion by repeating the ascending and descending strokes by repeating the ascending and descending strokes according to the principle described above. The repetition of the normal ascending and descending strokes of the piston 3, the leakage of the hydraulic oil, A sealing means is applied between the outer circumferential surface of the lower portion of the piston 3 and the inner circumferential surface of the cylinder for preventing inflow.

Sealing means applied between the outer circumferential surface of the lower portion of the piston 3 and the inner circumferential surface of the cylinder include a buffer seal, a load seal (hereinafter referred to as "U-packing"), .

Figures 2 and 3 show a conventional seal structure in contact with the piston lower diameter portion of the hydraulic breaker.

The seal structure in contact with the lower piston portion applied to most of the hydraulic breaker products includes a buffer seal 11 that first takes charge of the primary sealing at the time of the piston descent stroke and filters out the most hydraulic oil, And a dust seal 13 for preventing foreign matter from entering from the outside to the inside.

Also, most of the applied seals are generally made of polyurethane. The amount of hydraulic oil filtered by the sealing action of the buffer seal 11 and the U-packing 12 during the piston lowering stroke is considerably large. Particularly, the buffer seal 11 for primary sealing filters the most hydraulic oil Loses. At this time, during the descending stroke of the piston 3, the amount of the hydraulic fluid flowing in the piston descending stroke direction in the gap between the piston 3 and the cylinder 3a increases due to the rapid descending speed of the piston 3. [ Therefore, during the piston descent stroke, the operating oil flows into the assembly of the buffer seal 11 and the assembly of the U-packing 12 by the downward movement of the piston 3, and the continuous operation of the buffer seal 11 and the U- The hydraulic fluid filtered by the buffer seal 11 and the U-packing 12 flows through the eighth oil passage F8 through the inner diameter of the cylinder and the clearance e of the lower portion of the piston (see FIG. 4) The pressure in the buffer seal 11 and the U-packing 12 assembly is raised. Then, when the direction of motion of the piston 3 is changed from the descending stroke to the ascending stroke, the working oil filtered in the descending stroke is discharged to the low-pressure channel through the eighth passage F8.

Fig. 4 shows an enlarged view of the buffer seal 11 when the piston is lifted in a conventional seal structure in contact with the piston lower diameter portion of the hydraulic breaker. The operating fluid filtered by the buffer seal 11 and the U-packing 12 as the piston is shifted from the descending stroke to the ascending stroke passes through the assembly gap e between the piston lower diameter portion and the in- Pressure passage through the passage F8, thereby lowering the pressure around the buffer seal 11 and the U-packing 12 to a low-pressure state. The buffer seal 11 is moved upward by the frictional force between the piston lower diameter portion and the buffer seal 11 and the upper surface of the buffer seal 11 is assembled with the buffer seal 11 And contacts the upper surface. At this time, the piston rising stroke rate is very slow compared with the descending stroke, and the pressure around the buffer seal 11 is very low at a low pressure, so that the contact area (contact length length a) between the piston lower diameter portion and the buffer seal 11 becomes very short. Therefore, during the lifting stroke of the piston 3, the generation of heat is not high in the buffer seal 11 contacting the piston lower diameter portion.

Fig. 5 shows an enlarged view of the buffer seal 11 during piston downward movement in a conventional seal structure in contact with the piston lower diameter portion of the hydraulic breaker. The buffer seal 11 is moved in the downward direction by the frictional force between the piston lower diameter portion and the buffer seal 11 so that the buffer seal 11 Is brought into contact with the bottom surface of the seal assembly portion. Then, when the descending stroke of the piston progresses, the descending speed is increased, and the descending speed reaches the peak when the chisel is hit. Due to such a high speed during the piston descent stroke, a considerable amount of the working oil moves along the piston surface in the descending stroke direction, and at the same time, the speed of the working oil in the clearance between the piston lower diameter portion and the cylinder inner diameter increases, The amount of hydraulic fluid flowing in the piston descending stroke direction from the clearance between the piston and the piston increases. A large amount of hydraulic oil is filtered by the sealing of the buffer seal 11 and the U-packing 12, which are in contact with the piston lower diameter portion during the piston lowering stroke. In the buffer seal 11, The operating oil which is filtered by the buffer seal 11 and is filtered by the buffer seal 11 is filtered by the U-packing 12 responsible for the secondary sealing. Approximately 70% of the operating oil is filtered by the buffer seal 11, % Is filtered at the U-packing 12. As described above, during the piston descent stroke, the operating oil flows into the buffer seal assembly 11 and the U-packing 12 assembly part by the downward motion of the piston, and is continuously supplied to the buffer seal 11 and the U- The hydraulic oil filtered by the buffer seal 11 and the U-packing 12 is discharged through the eighth oil passage F8 to the low-pressure oil passage through the cylinder bore and the assembly clearance e of the piston lower- The pressure of the buffer seal 11 and the U-packing 12 assembly is raised, and the pressure in the buffer seal 11 assembly is raised to the level of 100 bar, which is halfway between the operating pressure and the low pressure. 5, the buffer seal 11 is compressed in the direction of the arrow shown on the buffer seal 11. When the buffer seal 11 is compressed in the direction of the arrow, The contact portion length a of the seal 11 is increased. At this time, heat generation is increased in the buffer seal 11 which is in contact with the lower piston portion due to the high descending speed of the piston, and furthermore, due to an increase in the length a of the contact portion of the buffer seal 11 contacting the piston lower- High heat is generated.

The buffer seal 11 used in the conventional hydraulic breaker is made of a polyurethane material having elasticity. Due to the nature of the polyurethane material, when the buffer seal 11 is exposed to a temperature of 80 ° C or more for a certain period of time, hardening proceeds, It becomes difficult to perform the function of the written seal. In addition, when the buffer seal 11 is cured as a whole, the buffer seal 11 may be partially broken and the particles may be released even at a low impact. If the released particles are introduced into the cylinder, the cylinder and the piston surface may be damaged May cause the hydraulic breaker to stop operating. In such a case, a loss occurs due to the downtime caused by the stoppage of operation, and the maintenance of the cylinder and the piston is costly.

Korean Patent Publication No. 10-2010-0132439

Disclosure of Invention Technical Problem [8] Accordingly, the present invention has been made keeping in mind the above problems occurring in the prior art, and an object of the present invention is to provide a hydraulic breaker which can prevent heat from being inevitably generated between a piston and a seal, So as to prevent the released particles from flowing into the cylinder.

The present invention is applied to a hydraulic breaker that hits a chisel by kinetic energy generated by reciprocating movement of a piston in a cylinder and crushes a pit explosion by impact energy converted through a chisel. And a sealing means provided between the inner circumferential surface of the cylinder and the inner circumferential surface of the cylinder so as to prevent leakage of operating oil and inflow of foreign matter due to repetition of the piston up and down strokes, the sealing means comprising: The buffering assembly includes a buffering assembly formed at the innermost one of the seal assemblies of the cylinder, and the buffering is inserted into the buffering assembly. The buffering is performed by performing primary sealing with respect to the outer circumferential surface of the lower neck of the piston .

The buffering is made of an engineering plastic material.

The buffering may be any one selected from the group consisting of polycarbonate and polyamide.

The buffering may be formed in a shape having a rectangular box-shaped cross section, or an inner circumferential surface opposed to the outer circumferential surface of the lower end of the piston may be formed in a convexly protruding shape.

According to the sealing structure of the hydraulic breaker according to the present invention, by the primary sealing of the buffering formed at the innermost part of the seal assembly part of the cylinder, which is one of the inner circumferential surfaces of the cylinder, relative to the outer circumferential surface of the lower part of the piston during the downward movement of the piston, The amount of hydraulic fluid filtered by the secondary seal member such as the buffer seal or the U-packing formed on the outer side of the buffering due to the filtering of the hydraulic oil is reduced as compared with the prior art. As a result, the pressure in the secondary seal member assembly The compression of the secondary sealing material is reduced. As a result, the length of the contact portion between the piston lower-diameter portion and the secondary sealing material becomes shorter than in the conventional case, thereby preventing or delaying the secondary sealing material.

In addition, when particles are detached from the secondary sealing material due to curing of the secondary sealing material, etc., it is possible to prevent the buffered particles from flowing into the cylinder, thereby preventing damage to the cylinder and the piston, Resulting in improved productivity and reduced maintenance costs.

And because of the engineering plastic material's characteristics, the buffering has a low strain due to heat and pressure, which maximizes the sealing effect for a long time.

1 is a schematic view showing an operation principle of a hydraulic breaker;
2 is a structural view of a conventional seal in contact with the piston lower portion;
3 is an enlarged view of a conventional seal structure in contact with the piston lower diameter portion;
Figure 4 is an enlarged view of a buffer seal in a conventional seal structure during piston lifting.
5 is an enlarged view of a buffer seal in a piston descending motion in a conventional seal structure.
6 is an enlarged view of a sealing structure in contact with the piston lower diameter portion according to an embodiment of the present invention;
7 is an enlarged view of a sealing structure in contact with a piston lower portion according to another embodiment of the present invention;
8 is an enlarged view of a sealing structure in contact with a piston lower diameter portion according to another embodiment of the present invention.

In the following description of the present invention, detailed description of known functions and configurations incorporated herein will be omitted when it may make the subject matter of the present invention rather unclear. The following terms are defined in consideration of the functions of the present invention, and these may be changed according to the intention of the user, the operator, or the like. Therefore, the definition should be based on the contents throughout this specification.

≪ Example 1 >

As shown in FIG. 6, the sealing structure of the hydraulic breaker according to an embodiment of the present invention strikes a chisel with kinetic energy generated through reciprocating movement of a piston in a cylinder, A buffer seal 11, which is a secondary sealing material, is used as a sealing means provided between the outer circumferential surface of the piston 3, which is a sliding portion by the chisel, and the inner circumferential surface of the cylinder 3a, The U-packing 12, the dust seal 13, and the buffer ring 14 as the primary sealing member, and the crushing operation of the crushed material by the chisel is the same as that of a conventional hydraulic breaker, so a detailed description thereof will be omitted , The sealing means, which is a feature of the present invention, will be described in detail.

The buffer seal 11 as the secondary sealing material, the U-packing 12 as the tertiary sealing material and the dust seal 13 are the same as the conventional ones and are sequentially installed from the inside (upper part of the drawing reference) to the outside And is inserted into a groove-shaped assembling portion which is opened toward the center on the inner peripheral surface of the cylinder 3a.

The buffer ring 14 which is the primary sealing material is newly constructed by the present invention and is provided inside the buffer seal 11 as a secondary sealing material (upper part in the drawing) (when the eighth flow path F8 is applied, 11) and the eighth flow path (F8) to take charge of the primary sealing prior to the buffer seal 11 which is the secondary sealing material.

The buffering assembly 14 is inserted into the buffering assembly 15. The buffering assembly 15 is formed on the inner circumferential surface of the cylinder 3a and has a groove shape opening toward the center. Is inserted into the buffering assembling section (15).

The buffer ring 14 may be a rectangular box section and the inner circumferential surface opposed to the outer circumferential surface of the piston 3 may be configured to be convex toward the piston.

In this structure, the buffering 14 performs the primary sealing, the buffer seal 11 performs the secondary sealing, and the U-packing 12 performs the tertiary sealing before the buffer seal 11 in the descending stroke of the piston.

In addition, while the buffering 14 has a material characteristic and the other seals 11, 12 and 13 are made of polyurethane material, MC nylon, polycarbonate, polyamide, nylon monomer, And the like.

Engineering plastic materials are generally characterized by high impact resistance, heat resistance and compressive strength, and very low compressive strain.

The operation of this embodiment will be described as follows.

A frictional force is generated between the lower diameter portion of the piston 3 and the buffer ring 14 and the buffer ring 14 is moved in the vertical direction by the buffer ring 14 when the piston 3 is switched from the up stroke to the down stroke, Even if the lower surface of the piston 3 contacts the lower surface of the buffering assembly 15 at a very high speed, hardening due to heat generation does not occur and the strain on the compressive force is very low. No deformation occurs.

Further, since a considerable amount of hydraulic oil is filtered by the primary sealing by the buffer ring 14 as the primary sealing material, the amount of hydraulic oil filtered by the secondary sealing by the buffer seal 11, which is the secondary sealing material, is relatively reduced. Therefore, the pressure rise in the assembly portion of the buffer seal 11 is significantly reduced compared to the conventional seal structure, so that a relatively low pressure acts on the buffer seal 11, so that the amount of compression of the buffer seal 11 is reduced, The contact length (a) of the buffer seal (11) in contact with the piston lower diameter portion is relatively shorter than that of the conventional seal structure, and heat generation due to friction between the piston lower diameter portion and the buffer seal (11) is reduced.

In addition, when the buffer seal 11 is cured as a whole after long-term use, and the buffer seal 11 is partially broken even if the buffer seal 11 is partially broken due to low impact, particles separated from the buffer seal 11 can move toward the inside of the cylinder. The buffering 14 intercepts the penetration of the particles that have disappeared from the buffer seal 11, thereby reducing the damage of the cylinder and the piston surface due to the particulate matter.

Since the pressure around the buffer seal 11 is very low at low pressure in the lifting motion of the piston, the length (a) of contact between the lower piston portion and the buffer seal 11 becomes very short, 11) is not high in heat generation.

≪ Example 2 >

7, the sealing means of the hydraulic breaker according to another embodiment of the present invention includes a U-packing 12 as a secondary sealing material, a dust seal 13 and a U- The crushing operation of the crushed material by the chisel is the same as that of a conventional hydraulic breaker, so a detailed description thereof will be omitted and the sealing means, which is a feature of the present invention, will be described in detail.

The U-packing 12 and the dust seal 13, which are the secondary sealing members, are the same as the conventional ones and are sequentially disposed from the inside (upper part of the drawing reference) to the outside (lower part of the drawing reference) And is inserted into a groove-shaped assembly portion which is opened toward the center.

The buffering 14, which is the primary sealing material, is installed inside the U-packing 12, which is the secondary sealing material, at the upper part of the drawing, and is responsible for the primary sealing.

The buffering 14 is inserted into the buffering assembly 15. The buffering assembly 14 is formed on the inner circumferential surface of the cylinder 3a and has a groove shape opening toward the center. (15).

In this structure, prior to the U-packing (12) in the descending stroke of the piston, the buffering (14) is the primary sealing and the U-packing (12) is the secondary sealing.

≪ Example 3 >

8, the sealing means of the hydraulic breaker according to still another embodiment of the present invention includes a buffer seal 11, a dust seal 13, And a buffering 14 which is a primary sealing material.

The buffer seal 11 and the dust seal 13, which are secondary sealing materials, are the same as the conventional ones and are sequentially disposed from the inside (upper portion of the drawing reference) to the outside (lower portion of the drawing reference) Shaped assembly portion which is formed to be open toward the front side.

The buffer ring 14, which is the primary sealing material, is installed inside the buffer seal 11 as a secondary sealing material (upper part in the drawing) to perform primary sealing before the buffer seal 11.

In this structure, prior to the buffer seal 11, the buffer ring 14 performs the primary sealing and the buffer seal 11 performs the secondary sealing in the descending stroke of the piston.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is to be understood that the invention is not limited to the disclosed exemplary embodiments. It is to be understood, however, that the invention is not to be limited to the specific forms thereof, which are to be considered as being limited to the specific embodiments, but on the contrary, the intention is to cover all modifications, equivalents, and alternatives falling within the spirit and scope of the invention as defined by the appended claims. .

11: Buffer seal, 12: U-packing
13: Dust seal, 14: Buffering
15: buffering assembly,

Claims (4)

The present invention is applied to a hydraulic breaker that hits a chisel by kinetic energy generated by reciprocating movement of a piston in a cylinder and crushes a pit explosion by impact energy converted through a chisel. And a sealing means provided between the inner circumferential surface and sealing means for preventing leakage of operating oil and inflow of foreign matter due to repetition of the ascending and descending strokes of the piston,
The sealing means
A buffering assembly formed at the innermost one of the seal assemblies of the cylinder, which is one of the inner circumferential surfaces of the cylinder,
And buffering inserted into the buffering assembly,
Characterized in that the buffering performs a primary sealing with respect to the outer circumferential surface of the lower neck portion of the piston. The method of claim 1,
Characterized in that it is made of engineering plastic material. 3. The method of claim 2,
Wherein the sealing member is one selected from the group consisting of polycarbonate and polyamide. The method of claim 1,
Wherein the piston is formed in a shape having a rectangular box-shaped cross section or an inner circumferential surface opposed to the outer circumferential surface of the lower portion of the piston is formed in a convexly protruding shape.

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