JPH06341403A - Accumulator of hydraulic down-the-hole drill - Google Patents

Abstract

PURPOSE:To dispence with a protection net of accumulator of a hydraulic down-the-hole drill and improve response speed. CONSTITUTION:In a tube body 11 a multi-pipe structure is provided. A working oil path 17 and an annular space concentrical thereto are formed. The annular space is divided into a gas chamber 19 and oil chamber 20 by means of bladder 18 and in a partitioning pipe 14 between the chamber 20 and the path 17 an oil hole 23 is bored. A plurality of distance rings 30 having uneveness formed on a contact face are continuously formed on the oil chamber 20 side of the partition tube 14 so that each contact face faces the oil hole 23. When working oil flows out from the oil chamber 20 the bladder 218 is not brought into pressure contact with the oil hole directly and thus no damage is generated and a sufficient oil path is formed with the uneveness on the contact face of the ring 30 thereby generating no disturbance on the flow of oil.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an accumulator for a hydraulic down the hole drill.

[0002]

2. Description of the Related Art In general, a hitting mechanism of a down-the-hole drill that uses compressed air as a power source is inefficient, has a large power loss, and has a certain limit in hitting force and the number of hits. Therefore, a down-the-hole drill striking mechanism using hydraulic pressure as a power source has been developed (WO80 / 013).
No. 00).

The striking mechanism of such a hydraulic down-the-hole drill is connected to the front end of the rod, and an accumulator for compensating for the pressure is also provided at the front end of the rod close to the striking mechanism in order to improve responsiveness. . In order to arrange the accumulator at such a position, the tubular body having the same diameter as the rod has a multi-tube structure to form an axially long annular space concentric with the hydraulic fluid passage, and the annular space is formed by a tubular bladder. The gas chamber and the oil chamber are separated from each other, and an oil hole is formed between the oil chamber and the hydraulic oil passage.

Along with the operation of the striking mechanism, the hydraulic oil repeatedly flows through the oil holes into the oil chamber of the accumulator and out of the oil chamber. When the hydraulic oil flows out of the oil chamber, the bladder is operated under gas pressure. Since the bladder is pressed against the oil hole, the portion of the bladder that abuts on the edge of the oil hole is damaged. Therefore, in order to prevent damage to the bladder, a protective net covering the oil holes has been conventionally provided.

[0005]

However, the protective mesh has no effect if the mesh is coarse, and if the mesh is fine, there is a problem that the passage of hydraulic oil is obstructed and the reaction of the accumulator becomes slow. SUMMARY OF THE INVENTION It is an object of the present invention to solve the above problems in an accumulator for a hydraulic down the hole drill, and to provide an accumulator for a hydraulic down the hole drill that does not require a protective net and has a quick reaction.

[0006]

SUMMARY OF THE INVENTION According to the present invention, a tubular body has a multi-tubular structure, a working oil passage and an annular space concentric with the working oil passage are formed, and the annular space is closed by a tubular bladder. Chamber and the oil chamber, and a plurality of distance rings that have oil holes formed in the partition pipe between this oil chamber and the hydraulic oil passage, and have irregularities on the joint surface, are installed on the oil chamber side of the partition pipe. Are connected to each other so that each joint surface faces the oil hole, thereby forming an accumulator for the hydraulic down-the-hole drill.

[0007]

With the operation of the striking mechanism, the hydraulic oil repeatedly flows through the oil hole into the oil chamber of the accumulator and out of the oil chamber. When the hydraulic oil flows out of the oil chamber, the bladder contacts the multiple distance rings that are connected in series and is not directly pressed against the oil hole by gas pressure, so there is no risk of damage by contacting the edges of the oil hole. . Since a sufficiently large oil passage is formed on the joint surface of the distance ring due to unevenness, the passage of hydraulic oil is not hindered and the reaction of the accumulator is not delayed.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS FIG. 1 is an explanatory view of the overall structure of a hydraulic down the hole drill according to an embodiment of the present invention, FIG. 2 is a partial vertical sectional view showing the structure of a high pressure accumulator of the hydraulic down the hole drill, and FIG. 3 is a hydraulic down the hole drill. Partial longitudinal cross-sectional view showing the structure of the low-pressure accumulator, FIG. 4 is a partial enlarged cross-sectional view near the joint surface of the high-pressure accumulator distance ring, FIG. 5 is a partial enlarged cross-sectional view near the joint surface of the low-pressure accumulator distance ring, FIG. 6 shows FIG.
FIG. 7 is a perspective view of the distance ring of the high pressure accumulator, and FIG. 8 is a perspective view of the distance ring of the low pressure accumulator.

Here, in the hydraulic down-the-hole drill, a rotating portion 50 is provided at the rear end, and a swivel portion 60, a connecting rod portion 70, a high / low pressure accumulator portion 80, a striking portion 90, and a bit 100 are sequentially connected in front of the rotating portion 50. (Not shown) supplies pressure oil to the striking portion 90 through the swivel portion 60 to drive the striking portion 90 to strike the bit 100 and to rotate the rotating portion 50.
From the connecting rod portion 70, the high and low pressure accumulator portion 80,
Drilling is performed by transmitting rotation through the striking part 90.

The high and low pressure accumulator section 80 comprises a high pressure accumulator 1 in the front and a low pressure accumulator 2 in the rear.
Is equipped with. The high pressure accumulator 1 includes an outer casing 12 and an inner casing 1 in an outer pipe body 11.
3. A multi-tube structure in which the partition tubes 14 are concentrically provided, and a flushing fluid passage 15 for discharging powder is provided between the tube body 11 and the outer casing 12, and low pressure oil is provided between the outer casing 12 and the inner casing 13. A high-pressure oil passage 17 is provided inside the passage 16 and the partition pipe 14. Inner casing 13
A tubular bladder 18 is provided in the annular space formed between the gas chamber 19 and the oil pipe 20, and the gas chamber 19 and the oil chamber 20 are separated from each other. Partition pipe 14 between the oil chamber 20 and the high-pressure oil passage 17
An oil hole 23 is bored in the pipe, and an annular groove 24 is cut on the outer circumference of the partition 14 at the position where the oil hole 23 is bored. A gas supply / discharge valve 21 is provided behind the gas chamber 19, and a gas passage 22 is provided from the gas supply / discharge valve 21 to the gas chamber 19. A gas having a predetermined pressure is injected into the gas chamber 19 from a gas supply / discharge valve 21 before assembly.

On the oil chamber 20 side of the partition pipe 14, a plurality of distance rings 30 are connected in series so that each joint surface 31 faces the oil hole 23. The distance ring 30 includes a concave portion 32 and a convex portion 3 on a radially inner portion of one joint surface 31.
3 is formed, and the outer portion is a recess 32 over the entire circumference.
Since it is further reduced, the oil passage 3 is formed between the joint surfaces 31.
4 is formed. The outermost 31R of each joint surface 31 that contacts the bladder 18 is a curved surface.

The low pressure accumulator 2 is an outer tubular body 1.
1 has a multi-tube structure in which an outer casing 12, a partition pipe 14, and an inner casing 13 are concentrically provided in a tubular body 11
Between the outer casing 12 and the outer casing 12 is a flushing fluid passage 15 for discharging powder, a low pressure oil passage 16 is between the outer casing 12 and the partition pipe 14, and a high pressure oil passage 17 is inside the inner casing 13. A tubular bladder 18 is provided in an annular space formed between the inner casing 13 and the partition tube 14, and a gas chamber 19 and an oil chamber 20 are separated from each other. An oil hole 23 is bored in the partition pipe 14 between the oil chamber 20 and the low-pressure oil passage 16, and an annular groove 24 is bored on the inner circumference of the partition pipe 14 at the position where the oil hole 23 is bored. There is. Gas chamber 1
A gas supply / discharge valve 21 is provided at the rear of 9, and a gas passage 22 is provided from the gas supply / discharge valve 21 to the gas chamber 19.

On the oil chamber 20 side of the partition pipe 14, a plurality of distance rings 30 are continuously provided so that each joint surface 31 faces the oil hole 23. The distance ring 30 includes a concave portion 32 and a convex portion 3 on a radially outer side portion of one joint surface 31.
3 is formed, and the inner portion is a concave portion 32 over the entire circumference.
Since it is further reduced, the oil passage 3 is formed between the joint surfaces 31.
4 is formed. The innermost 31R of each joint surface 31 that contacts the bladder 18 is a curved surface.

With the operation of the striking mechanism, the high pressure oil passage 17
From and to the high pressure accumulator 1 and from the low pressure oil passage 16 to and from the low pressure accumulator 2. The hydraulic oil flows into the oil chamber 20 through the oil hole 23 and flows out of the oil chamber 20, but when the hydraulic oil flows out of the oil chamber 20, the bladder 18 contacts the plurality of distance rings 30 that are continuously provided, Since the oil pressure is not directly contacted with the oil hole 23 by the gas pressure, there is no possibility that the edge of the oil hole 23 is contacted with and damaged. A recess 32 is formed in the joining surface 31 of the distance ring 30.
Since the sufficiently large oil passage 34 is formed by the convex portion 33 and the convex portion 33, the passage of the hydraulic oil is not hindered and the reaction of the accumulator is not delayed.

[0015]

As described above, in the accumulator of the hydraulic down-the-hole drill of the present invention, there is no possibility that the bladder is pressed against the oil hole by the gas pressure and the portion of the bladder abutting the edge of the oil hole is damaged. Therefore, it is not necessary to provide a bladder protection net on the oil hole, and a sufficiently large oil passage is formed on the joint surface of the distance ring, so that the flow of hydraulic oil is not obstructed and the reaction is quick.

[Brief description of drawings]

FIG. 1 is an explanatory diagram of the overall configuration of a hydraulic down the hole drill that is an embodiment of the present invention.

FIG. 2 is a partial vertical cross-sectional view showing the configuration of a high pressure accumulator of a hydraulic down the hole drill.

FIG. 3 is a partial vertical cross-sectional view showing the configuration of a low pressure accumulator of a hydraulic down the hole drill.

FIG. 4 is a partially enlarged cross-sectional view of the vicinity of a joint surface of a distance ring of a high pressure accumulator.

FIG. 5 is a partially enlarged cross-sectional view in the vicinity of a joint surface of a distance ring of a low pressure accumulator.

6 is a cross-sectional view taken along the line AA of FIG.

FIG. 7 is a perspective view of a distance ring of the high pressure accumulator.

FIG. 8 is a perspective view of a distance ring of the low pressure accumulator.

[Explanation of symbols]

 1 High Pressure Accumulator 2 Low Pressure Accumulator 11 Tubular Body 12 Outer Casing 13 Inner Casing 14 Partition 16 Low Pressure Oil Passage 17 High Pressure Oil Passage 18 Bladder 19 Gas Chamber 20 Oil Chamber 21 Gas Supply / Discharge Valve 23 Oil Hole 30 Distance Ring 31 Joint Surface 32 concave part 33 convex part 34 oil passage

Claims (1)

[Claims] 1. A multi-tube structure is formed in the tubular body to form a hydraulic oil passage and an annular space concentric with the hydraulic oil passage, and the annular space is divided into a gas chamber and an oil chamber by a cylindrical bladder. Then, a plurality of distance rings, each having an oil hole in the partition between the oil chamber and the hydraulic oil passage and having irregularities formed on the joint surface, are provided on the oil chamber side of the partition with oil on each joint surface. Accumulator for hydraulic down-the-hole drills that are connected in series so as to face the hole.