KR101712553B1 - Hydraulic Breaker - Google Patents

Abstract

The present invention provides a hydraulic breaker capable of improving durability even if the hydraulic breaker receives continuous impact pressure in a crushing work of an object to be crushed. According to the present invention, the hydraulic breaker includes a cylinder, a piston, a back head, a chisel, a valve, a cylinder bush, and a seal. The cylinder has a cylinder upper chamber and a cylinder lower chamber on the upper part and the lower part, respectively. The piston is installed to vertically slide by passing through the cylinder. The back head is installed on the upper side of the cylinder and includes a gas chamber inserting the upper end of the piston. The chisel is installed on the lower side of the cylinder to be hit by the piston. The valve enables the piston to reciprocate by selectively supplying a hydraulic fluid to the cylinder upper chamber and the cylinder lower chamber. The cylinder bush is installed between the cylinder and the back head and is mounted on an opening on the upper end of the cylinder. The cylinder bush enables the piston to penetrate the same. The seal is mounted on the inner circumference of the cylinder bush while coming into contact with the cylinder upper chamber and maintains airtightness between the outer circumference of the piston. The seal is formed of a fiber plastic composite material.

Description

{Hydraulic Breaker}

BACKGROUND OF THE INVENTION 1. Field of the Invention [0001] The present invention relates to a hydraulic breaker that uses hydraulic pressure as a drive source to crush a pit explosion.

The hydraulic breaker transfers the kinetic energy generated by the reciprocating motion of the piston to the chisel and transforms it into impact energy. The impact breaker breaks down the pitta of the rock or concrete by the impact energy. When the hydraulic breaker is connected to the hydraulic power source of the excavator, hydraulic oil can be supplied from the hydraulic power source and operated.

The hydraulic breaker typically includes a cylinder having an upper cylinder portion and a lower cylinder portion, a piston slidably installed vertically through the cylinder, a chisel installed at a lower portion of the cylinder so as to be struck by the piston, And a valve that selectively reciprocates the piston to reciprocate the operating fluid.

A cylinder bush is mounted on the top opening of the cylinder. The cylinder bushing penetrates the piston and has a seal on its inner circumferential surface. The seal keeps airtightness between the cylinder bush and the piston so that the hydraulic oil does not leak, thereby sealing the cylinder chamber. Most seals are made of PTFE (Polytetrafluoroethylene), which is manufactured by sintering method to bond particles using high temperature and high pressure instead of chemical bonding.

On the other hand, since the seal is in contact with the operating oil on the cylinder chamber, it is exposed directly to the impact pressure generated in the operation of the hydraulic breaker. However, if the seal made of PTFE material is continuously exposed to an impact pressure exceeding several tens of times a day, cracks may occur between the particles of the PTFE material. This allows the particles to escape from the seal and enter the interior of the cylinder. In the course of reciprocating motion of the piston, when particles enter the gap between the cylinder and the piston, serious damage to the cylinder and the piston may occur.

Disclosure of Invention Technical Problem [8] The present invention provides a hydraulic breaker capable of increasing the durability even under a continuous impact pressure during crushing operation of a pit boat.

In order to achieve the above object, a hydraulic breaker according to the present invention includes a cylinder, a piston, a back head, a chisel, a valve, a cylinder bush, and a seal. The cylinder has an upper cylinder chamber and a lower cylinder chamber on the upper and lower sides. The piston is slidably mounted up and down through the cylinder. The back head is disposed on the upper side of the cylinder and has a gas chamber for inserting the upper end portion of the piston. The chisel is installed on the lower side of the cylinder so as to be hit by the piston. The valve selectively supplies the operating fluid to the lower cylinder and upper cylinder to reciprocate the piston. A cylinder bush is disposed between the cylinder and the back head and mounted in the upper opening of the cylinder, and penetrates the piston. The seal is attached to the inner circumferential surface of the cylinder bush in contact with the upper chamber of the cylinder to maintain airtightness with the outer circumferential surface of the piston, and is made of a fibrous plastic composite material.

According to the present invention, there is no fear that the particles are released from the seal due to the impact pressure of the upper chamber, which is inevitably generated in the operation of the hydraulic breaker, so that damage to the cylinder and the piston can be prevented. In addition, since the damage to the cylinder and the piston is prevented, loss of working time can be prevented, and working efficiency and productivity can be improved.

1 is a block diagram of a hydraulic breaker according to an embodiment of the present invention.
Fig. 2 is an enlarged cross-sectional view of region A in Fig. 1. Fig.
Fig. 3 is an exploded perspective view of the cylinder bush and seal shown in Fig. 2, which is exploded. Fig.
4 is a cross-sectional view showing another example of the cylinder bush.
5 is a graph showing an example of a pressure waveform formed in the high-pressure generating portion when the hydraulic breaker operates.

The present invention will now be described in detail with reference to the accompanying drawings. Here, the same reference numerals are used for the same components, and a detailed description of known functions and configurations that may unnecessarily obscure the gist of the present invention will be omitted. Embodiments of the present invention are provided to more fully describe the present invention to those skilled in the art. Accordingly, the shapes and sizes of the elements in the drawings and the like can be exaggerated for clarity.

1 is a block diagram of a hydraulic breaker according to an embodiment of the present invention. Fig. 2 is an enlarged cross-sectional view of region A in Fig. 1. Fig. Fig. 3 is an exploded perspective view of the cylinder bush and seal shown in Fig. 2, which is exploded. Fig.

1 to 3, the hydraulic breaker 100 includes a cylinder 110, a piston 120, a back head 130, a chisel 140, a valve 150, a cylinder bush 160 And a plurality of seals 171, 172, 173.

The cylinder 110 includes an upper cylinder chamber 111 formed on the upper side and a cylinder lower chamber 112 formed on the lower side. The cylinder 110 has a vertically penetrating hollow and can penetrate the piston 120 through the hollow. The cylinder 110 has a cylinder low pressure chamber 113 and a cylinder switching chamber 114 between the cylinder upper chamber 111 and the cylinder lower chamber 112. The cylinder low pressure chamber (113) is disposed above the cylinder conversion chamber (114).

The piston 120 is slidably mounted vertically through the cylinder 110. The piston 120 has an upper diameter portion 121 and a lower diameter portion 122 formed at upper and lower portions thereof. The upper diameter portion 121 and the lower diameter portion 122 are each formed in a shape having a larger diameter than other portions of the piston 120. The upper diameter portion 121 and the lower diameter portion 122 are disposed between the upper cylinder chamber 111 and the lower cylinder chamber 112. The upper diameter portion 121 is disposed in contact with the operating oil of the cylinder upper chamber 111 and the lower diameter portion 122 is disposed in contact with the operating oil of the cylinder lower chamber 112.

The back head 130 is disposed on the upper side of the cylinder 110. The back head 130 has a gas chamber 131 for inserting the upper end portion of the piston 120. A gas such as nitrogen gas is injected into the gas chamber 131. The piston 120 can be pressed downward by the pressure of the gas injected into the gas chamber 131.

The chisel 140 is installed on the lower side of the cylinder 110 so as to be hit by the piston 120. The upper portion of the chisel 140 can be inserted through the lower end opening of the cylinder 110. The chisel 140 can be slidably supported up and down along the inner wall of the cylinder 110 to be inserted into the cylinder 110. The chisel 140 converts the kinetic energy of the piston 120 into impact energy and crushes the pita wave 10 such as rock or concrete by the impact energy.

The valve 150 selectively supplies the operating oil to the cylinder lower chamber 112 and the cylinder upper chamber 111 to reciprocate the piston 120. For example, the valve 150 has a valve switching chamber 151 and a valve upper chamber 152. The valve 150 is connected to the hydraulic pump 181 by the first flow path 191. The cylinder lower chamber 112 is connected to the hydraulic pump 181 by the second flow path 192. The valve 150 is connected to the upper cylinder chamber 111 by the third flow path 193. The valve upper chamber 111 is connected to the hydraulic pump 181 by the fourth flow path 194. The valve 150 is connected to the working oil tank 186 by the fifth flow path 195. The cylinder low pressure chamber (113) is connected to the working oil tank (186) by a sixth flow path (196). The cylinder switching chamber (114) is connected to the valve switching chamber (151) by a seventh channel (197). The hydraulic oil pump 181 can control the hydraulic oil discharge by the pump valve 182. [ Examples of the operation of the valve 150 and the hydraulic pump 181 will be described later.

The cylinder bush 160 is disposed between the cylinder 110 and the back head 130 and mounted in the upper opening of the cylinder 110. The cylinder bushing 160 has a hollow portion vertically penetrating therethrough, and can penetrate the piston 120 through the hollow portion. The cylinder bush 160 can be inserted into the cylinder 110 through the upper end opening of the cylinder 110.

The seal 171 is mounted on the inner circumferential surface of the cylinder bush 160 in contact with the upper cylinder chamber 111 to maintain airtightness with the outer circumferential surface of the piston 120. That is, the seal 171 can seal the upper cylinder chamber 111 by preventing the hydraulic oil from leaking between the cylinder bush 160 and the piston 120. The seal 171 may be in the form of a ring. The cylinder bush 160 may have a mounting groove formed in the inner peripheral surface thereof in the inner peripheral direction. The seal 171 can be fitted and fixed in the mounting groove. The seal 171 may be sized to be pressed onto the outer circumferential surface of the piston 120 while being fitted in the mounting groove.

The seal 171 is made of a fibrous plastic composite material. The fibrous plastic composite material is a fibrous material having a strongly bonded structure and high heat resistance, and a material molded from plastic having high compressive strength. Accordingly, the seal 171 may have heat resistance that can withstand the heat generated during the wetting with the piston 120, for a long time compared to the sintered material. The seal 171 has a higher compressive strength than the sintered material, so that resistance to deformation can also be improved. Further, since the seal 171 contains fibers rather than particles, the seal 171 may have a property that the particles are not likely to be released even if they are exposed to a continuous impact pressure.

At this time, the fibrous plastic composite material may be formed of polyamide. For example, the fibers of the fibrous plastic composite material may be formed of polyamide. Alternatively, the plastic of the fibrous plastic composite may be formed of polyamide. Both the fiber and the plastic of the fibrous plastic composite material may be formed of polyamide.

Three additional seals 172, 173 may be provided on the top of the seal 171. The additional seals 172 and 173 are respectively mounted on the inner circumferential surface of the cylinder bush 160 to further maintain the outer circumferential surface of the piston 120 and the airtightness. The additional seals 172, 173 may be mounted to the cylinder bush 160 in the same manner as the seal 171. The additional seal 173 on the uppermost side of the additional seals 172, 173 may have a different shape than the remaining additional seals 172. The additional seals 172 and 173 may be made of the same fibrous plastic composite as the seal 171, but may be made of a PTFE material. As another example, a seal 171 'and two additional seals 172, 173 may be mounted on the inner circumferential surface of the cylinder bush 160', as shown in FIG. In this case, the seal 171 'may have the same shape as the lower additional seal 172.

A plurality of outer seals 174 may be mounted between the outer circumferential surface of the cylinder bush 160 and the inner circumferential surface of the cylinder 110 to maintain airtightness between the cylinder bush 160 and the cylinder 110. The outer seal 174 may be in the form of a ring. The cylinder bush 160 may have a mounting groove formed in the outer peripheral surface thereof in the outer peripheral direction. The outer seal 174 can be fitted and fixed in the mounting groove. The outer seal 174 may be sized to be pressed onto the inner circumferential surface of the cylinder 110 while being fitted in the mounting groove. The outer seal 174 may be made of a variety of materials such as PTFE.

An example of the operation of the hydraulic breaker 100 will be described as follows.

When the operating oil discharged from the operating oil pump 181 is supplied to the cylinder lower chamber 112 through the second flow path 912, the pressure in the cylinder lower chamber 112 is raised to start the rising stroke of the piston 120. At this time, the valve upper chamber 152 is formed with high pressure by the hydraulic oil supplied from the hydraulic pump 181 through the fourth flow path 194. The cylinder low pressure chamber 113 is connected to the working oil tank 186 by the sixth flow path 196 and is in a low pressure state so that the valve switching chamber 151 communicates with the cylinder conversion chamber 114 by the seventh flow path 197 A low pressure is formed. Accordingly, the third oil passage 193 communicates with the fifth oil passage 195 and the low pressure is maintained in the cylinder upper chamber 111.

Thereafter, when the piston 120 continues to rise and the lower surface of the lower diameter portion 122 reaches the cylinder switching chamber 114, the cylinder lower chamber 112 connected to the operating oil pump 181 moves to the cylinder switching chamber 114 And the valve switching chamber 151 is communicated with the valve switching chamber 151 by the seventh flow path 197. Thus, the valve switching chamber 151 is formed with the same high pressure as the valve upper chamber 152. At this time, since the hydraulic pressure of the valve switching chamber 151 is larger than the valve upper chamber 152, the valve 150 is switched so that the first flow path 191 and the third flow path 193 are communicated with each other. Therefore, a high pressure such as the cylinder lower chamber 112 is formed in the cylinder upper chamber 111. At this time, since the upper surface of the upper diameter portion 121 has a larger hydraulic pressure area than the lower surface of the lower diameter portion 122, the rising stroke of the piston 120 is stopped and the descending stroke starts. The piston 120 has potential energy in the cylinder conversion chamber 114 where the descending stroke starts.

The position energy of the piston 120 is converted into kinetic energy until the piston 120 starts to descend and comes into contact with the chisel 140. When the piston 120 comes into contact with the piston 140, I.e., the hitting force, and is transmitted to the pita boot 10 via the chisel 140. [ At this time, when the upper surface of the lower diameter portion 122 passes the cylinder switching chamber 114, the valve switching chamber 151 is communicated with the cylinder low pressure chamber 113 by the seventh channel 197 and the pressure is lowered. Accordingly, the valve 150 is returned, and the third flow path 193 is communicated with the fifth flow path 195. Therefore, the pressure in the cylinder upper chamber 111 is lowered, and the piston 120 is raised again.

The hydraulic breaker 100 breaks the pita power 10 by transferring the impact energy to the pita power 10 by repeating the ascending and descending strokes by the above-described principle. In the crushing operation, the pressure waveform of the high-pressure generating portion shows a very severe fluctuation before and after the descent stroke of the piston 120 progresses and the piston 120 hits the chisel 140.

For example, as shown in Fig. 5, it can be confirmed that a very large impact pressure is generated during a very short time after the impact and immediately after the impact. This impact pressure is continuously generated when the hydraulic breaker operates. If you work 8 hours a day at 300 BPM (Blow per Minute) and assume an operating rate of 25%, you get 36,000 blows per day (2 hours x 60 minutes x 300 BPM), which is equal to the number of times the impact has occurred.

Even if the seals 171 and 171 'that are in contact with the operating oil of the cylinder upper chamber 111 are continuously exposed to the impact pressure due to the impact pressure exceeding several tens of times per day in the cylinder upper chamber 111, Since the seals 171 and 171 'are made of a fibrous plastic composite material, the particles may not be separated. Therefore, since the particles do not flow into the gap between the cylinder 110 and the piston 120, damage to the cylinder 110 and the piston 120 can be prevented.

While the present invention has been particularly shown and described with reference to exemplary embodiments thereof, it is clearly understood that the same is by way of illustration and example only and is not to be taken by way of limitation and that those skilled in the art will recognize that various modifications and equivalent arrangements may be made therein. It will be possible. Accordingly, the true scope of protection of the present invention should be determined only by the appended claims.

110 .. cylinder 111. cylinder upper chamber
112 .. cylinder bottom chamber 113 .. cylinder low pressure chamber
114 .. cylinder switching chamber 120 .. piston
121. Upper diameter portion 122 .. Lower diameter portion
130 .. back head 131 .. gas chamber
140 .. Chisel 150 .. Valve
151 .. Valve switching chamber 152 .. Valve upper chamber
160, 160 '.. cylinder bushes 171, 171' .. seal

Claims (2)

A cylinder having an upper cylinder chamber and a lower cylinder chamber formed on the upper and lower sides thereof;
A piston slidably moving up and down through the cylinder;
A back head disposed on the cylinder and having a gas chamber for inserting an upper end portion of the piston;
A chisel installed below the cylinder to be hit by the piston;
A valve for selectively supplying operating fluid to the lower cylinder chamber and the upper cylinder chamber to reciprocate the piston;
A cylinder bush disposed between the cylinder and the back head and mounted to an upper opening of the cylinder, the cylinder bush passing through the piston; And
The cylinder bushing is mounted on the inner circumferential surface of the cylinder bush while being in contact with the cylinder and maintains the airtightness with the outer circumferential surface of the piston. Even if the piston is continuously exposed to the impact pressure applied to the cylinder- A seal made of a fibrous composite material formed of polyamide so as not to be separated;
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