JP2014136302A - Hydraulic breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or suppress mixing of foreign matters such as dust into a hydraulic striking mechanism, in a hydraulic breaker that is provided with a cylinder in which a front head portion and a cylinder portion are integrated, and has a striking chamber in a portion between the front head portion and the cylinder portion.SOLUTION: A hydraulic breaker 10 has an annular oil groove 30 formed in a plurality of stages in a cylinder shaft direction, on an inner peripheral surface of a striking chamber 2 of a cylinder 1.

Description

  The present invention relates to a hydraulic breaker including a cylinder in which a front head portion and a cylinder portion are integrated, and a piston is slidably fitted in the cylinder portion via a cylinder liner. The present invention relates to a technique for preventing or suppressing the entry of foreign matters such as the above.

Conventionally, a split type hydraulic breaker in which a front head and a cylinder are divided is known (see, for example, Patent Document 1).
This type of hydraulic breaker, like the hydraulic breaker 100 shown in FIG. 3 as an example, has a cylinder 101 at the center in the axial direction, a front head 102 connected to the front side of the cylinder 101, and a back side at the rear side. The head 103 is connected. The front head 102, the cylinder 101, and the back head 103 are fastened to each other by a long through bolt 121.

  A piston 105 is slidably fitted in the cylinder 101. A front cap 104 is coaxially provided on the front end side of the front head 102, and a front holder 109 is coaxially provided in the middle of the front head 102. A chisel 112 is inserted into the front head 102 from the front end side, and the chisel 112 is held on the coaxial line CL with the piston 105 by a front cap 104 and a front holder 109. A striking chamber 111 is formed between the rear end side of the chisel 112 and the front end side of the piston 105. The striking chamber 111 is provided at the upper end portion of the front head 102.

  The cylinder 101 is provided with a known hydraulic striking mechanism including a control valve 106 and a stroke control valve 107. By supplying pressure oil to the cylinder 101 via a control valve 106 from a hydraulic supply source (not shown). The piston 105 can be moved back and forth on the axis CL by switching the flow path of the pressure oil. The chisel 112 can reciprocate a predetermined distance in the axial direction by striking the piston 105. The chisel 112 is restricted from moving in the axial direction by the rod pin 108, and its reciprocating range is limited.

  Here, when the hydraulic breaker 100 is used, foreign matter such as dust in the crushing work atmosphere and built-in component wear powder flows to the hydraulic striking mechanism side. A dust seal 120 is provided to prevent foreign matter entering from the inside from entering the gap between the cylinder inner surface and the piston 105. Thereby, the dust seal 120 installed on the front side of the cylinder 101 prevents foreign matter from entering the hydraulic striking mechanism. However, although foreign matter can be prevented from entering the hydraulic striking mechanism to some extent by the dust seal 120, the life of the dust seal 120 may be shortened depending on the use conditions of the hydraulic breaker 100, such as when dust is likely to scatter.

On the other hand, when foreign matter such as dust in the atmosphere of the crushing operation by the hydraulic breaker 100 or wear powder of built-in parts enters the striking chamber 111, the rod has an inner diameter of the striking chamber 111 of the same size as the outer diameter of the piston 105 Foreign matter easily enters the hydraulic striking mechanism together with the lubricating grease.
Therefore, in this type of hydraulic breaker, it is necessary to secure a certain amount of volume of the striking chamber. The reason is that it is necessary to minimize the pressure change of the air in the striking chamber due to the reciprocating motion of the piston. In other words, when the pressure change in the striking chamber increases, not only the discharge to the atmosphere side but also the entry of foreign matters such as dust to the hydraulic striking mechanism side is likely to occur, so a certain amount of volume is required. .

  Here, the machining for enlarging the inner diameter of the striking chamber is the above-described split hydraulic breaker, because the front head and the cylinder are divided, so that the striking chamber is the upper end portion of the front head as described above. Can be provided. Therefore, the machining tool can easily access the front head from the hydraulic striking mechanism side. Therefore, machining for expanding the inner diameter of the striking chamber can be realized relatively easily.

JP 2008-114297 A

  By the way, in the split type hydraulic breaker, as described above, the front head, the cylinder and the back head are fastened to each other with long through bolts. There is a potential problem of slackening. Accordingly, the present inventors have been researching and developing a hydraulic breaker having an integral cylinder structure in order to fundamentally solve the problems based on such a long through bolt. The integrated cylinder structure is an integrated cylinder in which a front head portion into which a chisel is inserted from the front end side and a cylinder portion into which a piston is slidably fitted via a cylinder liner is integrated. A striking chamber is provided in a portion between the front head portion and the cylinder portion of the integrated cylinder. If the hydraulic breaker has an integrated cylinder structure, the cylinder and back head can be fastened to each other with short bolts, eliminating the need for long through bolts and eliminating the problems of bolt twisting and loosening. Can do.

However, the hydraulic breaker with an integrated cylinder structure has a long integrated cylinder, and the striking chamber is located near the axial center of the cylinder. It is difficult to machine a deep hole and a large inner diameter with respect to the striking chamber located in the center. That is, in the hydraulic breaker having an integral cylinder structure, there is a problem that it is difficult to provide a large-diameter portion that secures a constant amount of the striking chamber.
Accordingly, the present invention has been made paying attention to such problems, and in a hydraulic breaker having an integrated cylinder structure in which the front head portion and the cylinder portion are integrated, the contact between the cylinder and the cylinder liner is achieved. An object of the present invention is to provide a hydraulic breaker having an integrated cylinder structure that can prevent or suppress entry of foreign matter such as dust and wear powder of built-in parts into a part.

  In order to solve the above-described problem, a hydraulic breaker according to an aspect of the present invention includes a front head portion into which a chisel is inserted from the front end side thereof, and a cylinder portion into which a piston is slidably fitted via a cylinder liner. Is a hydraulic breaker having a striking chamber in a portion between the front head portion and the cylinder portion, and the cylinder has an inner peripheral surface of the striking chamber. And an annular oil groove formed in a plurality of stages in the axial direction of the cylinder.

  According to the hydraulic breaker according to one aspect of the present invention, the cylinder has a structure in which the front head portion and the cylinder portion are integrated, and the impact chamber of the cylinder has oil grooves formed in a plurality of stages in the axial direction of the cylinder. Therefore, grease can be retained in each oil groove. Since the oil groove is formed in a plurality of stages in the axial direction of the cylinder, the oil groove as a whole functions as a labyrinth seal. In other words, the plurality of oil grooves serve as a dust reservoir (dust pocket) having a labyrinth seal function, and foreign matters such as dust in the working environment of the hydraulic breaker and wear powder of built-in parts can be retained. Therefore, it is possible to prevent or suppress entry of foreign matters such as dust into the hydraulic striking mechanism (hydraulic system). Then, if the machining is such that the oil grooves are provided in a plurality of stages, machining can be performed more easily than when machining a deep hole and a large inner diameter with respect to the striking chamber.

  Here, in the hydraulic breaker according to one aspect of the present invention, the plurality of stages of oil grooves are provided adjacent to each other so as to function as a labyrinth seal, and exhibit a corrugated shape in a cross-sectional view along the axial direction. It is preferable to form. Such a configuration is suitable for preventing or suppressing entry of foreign matter such as dust into the hydraulic system while eliminating the need for a special seal.

  Further, the shape of each oil groove includes an inclined portion formed on the front side in the axial direction, a wall surface portion formed on the rear side in the axial direction, and a bottom portion formed between the inclined portion and the wall surface portion. And the inclined portion is formed of an inclined surface formed so as to increase the inner diameter of the striking chamber from the axial front side toward the axial rear side, and the wall surface portion is orthogonal to the axial direction. If the shape is made of a wall surface, it is more preferable to prevent or suppress entry of foreign matter such as dust into the hydraulic striking mechanism.

  As described above, according to the present invention, in the hydraulic breaker that includes the cylinder in which the front head portion and the cylinder portion are integrally structured and has a striking chamber in a portion between the front head portion and the cylinder portion, the integral structure Since the cylinder's striking chamber is provided with multiple stages of oil grooves, grease is held in the oil grooves to form dust pockets, and the multi-stage oil grooves form a corrugated shape as a whole, functioning as a labyrinth seal. Foreign matter can be retained in the oil groove. Therefore, the entry of foreign matter such as dust into the hydraulic striking mechanism can be prevented or suppressed.

BRIEF DESCRIPTION OF THE DRAWINGS It is a figure explaining one Embodiment of the hydraulic breaker which concerns on this invention, The figure shows the hydraulic breaker in the cross section containing the axis line. The entry path of foreign matter such as dust is also indicated by arrows. It is a principal part (A part) enlarged view of the part of the oil groove provided in the striking chamber in FIG. It is a figure explaining the conventional split type hydraulic breaker, The figure has shown the hydraulic breaker in the cross section containing the axis line. The entry path of foreign matter such as dust is also indicated by arrows.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate.
As shown in FIG. 1, the hydraulic breaker 10 has an integrated structure of a front head portion 41 into which the chisel 12 is inserted from the front end side thereof and a cylinder portion 42 into which the piston 5 is slidably fitted. A cylinder 1 is provided.
Specifically, the hydraulic breaker 10 has a cylinder portion 42 on the rear side in the axial direction of the cylinder 1, and the front side of the cylinder portion 42 is integrally formed with the cylinder portion 42 as a front head portion 41, and the back head 3 at the rear end. Are connected. The back head 3 is fastened to the rear end of the cylinder 1 by a short bolt 21. The piston 5 is slidably fitted into the cylinder portion 42 via cylinder liners 23 and 24.

  A front cap 4 is provided coaxially on the front side of the front head portion 41, and a front holder 9 is provided coaxially on the rear side of the front head portion 41. The chisel 12 is inserted into the front head portion 41 from the front end side, and the chisel 12 is held on the coaxial line CL with the piston 5 by the front cap 4 and the front holder 9. A striking chamber 2 is formed between the rear end side of the chisel 12 and the front end side of the piston 5. The striking chamber 2 is provided in a portion between the front head portion 41 and the cylinder portion 42.

  The cylinder portion 42 of the cylinder 1 is provided with a known hydraulic striking mechanism including a control valve 6 and a stroke control valve 7, and pressure oil is supplied from the hydraulic supply source (not shown) to the cylinder portion 42 via the control valve 6. By switching the pressure oil flow path, the piston 5 can move back and forth on the axis CL. The chisel 12 can reciprocate a predetermined distance in the axial direction by striking the piston 5. The chisel 12 is restricted from moving in the axial direction by a rod pin (not shown), and its reciprocating range is limited.

  A cylinder liner 23 is fitted on the inner surface of the tip of the cylinder portion 42 via a washer 22. A dust seal 20 is provided on the inner surface of the tip of the cylinder liner 23 so as to prevent foreign matter such as dust entering from the front head portion 41 side from entering the gap between the inner surface of the cylinder 1 and the piston 5. . Thereby, the dust seal 20 installed on the front side of the cylinder portion 42 prevents foreign matter from entering the hydraulic striking mechanism.

  Here, as shown in FIG. 1, the striking chamber 2 of the hydraulic breaker 10 is not processed so as to enlarge the inner diameter of the striking chamber 2 as a whole, and has a slight gap with respect to the outer shape of the piston 5. However, the corrugated step formed by forming oil grooves 30 in multiple stages in the axial direction of the cylinder 1 on the inner wall surface of the striking chamber 2 functions as a labyrinth seal. It has been subjected.

  As shown in an enlarged view of the main part (cross section of the inner wall surface of the striking chamber) in FIG. 2, the five oil grooves 30 arranged in the axial direction at equal intervals are formed on the inner wall surface of the striking chamber 2 as a plurality of oil grooves 30. Is processed into an annular shape. Each oil groove 30 has the same shape, and a plurality of stages of oil grooves 30 are provided adjacent to each other so as to function as a labyrinth seal by mutual cooperation, and have a corrugated shape in a sectional view along the axial direction. It is formed to present.

  Each oil groove 30 has an inclined portion 31 formed on the front side in the axial direction, a wall surface portion 33 formed on the rear side in the axial direction, and a bottom portion 32 formed between the inclined portion 31 and the wall surface portion 33. doing. The inclined portion 31 is formed by an inclined surface formed so as to increase the inner diameter of the striking chamber 2 from the front side in the axial direction, which is the entry direction of foreign matters such as dust, from the rear side in the axial direction. On the other hand, the wall surface portion 33 is formed by a 90 ° wall surface orthogonal to the axial direction while being formed on the rear side in the axial direction on the hydraulic striking mechanism side. The bottom 32 is formed by a cylindrical surface that is coaxial with the axis CL.

Next, functions and effects of the hydraulic breaker 10 will be described.
The hydraulic breaker 10 supplies pressure oil to the cylinder portion 42 via a control valve 6 from a hydraulic supply source (not shown). As a result, the flow path of the pressure oil is switched by the control valve 6 so that the piston 5 moves back and forth on the axis line CL, and the chisel 12 reciprocates a predetermined distance in the axial direction by striking the piston 5, thereby Can be operated.
In particular, the hydraulic breaker 10 has an integrated structure of a front head portion 41 into which the chisel 12 is inserted from the front end side and a cylinder portion 42 into which the piston 5 is slidably fitted through the cylinder liners 23 and 24. Since the cylinder 1 is provided, a long through bolt is unnecessary, and the problem of bolt twisting and loosening can be solved.

  By the way, when the hydraulic breaker is used, foreign matters such as dust in the crushing work atmosphere and internal component wear powder are generated. The wear of the built-in parts mainly occurs from the front cap 4, the front holder 9, the striking surface of the chisel 12, and the like. As shown in FIG. 1, when the hydraulic breaker 10 is operated, the entry path of foreign matters such as dust into the hydraulic breaker 10 is mainly entered from the gap between the fitting portions of the chisel 12 and the front cap 4. Flow to the side. Intrusion of foreign matter into the hydraulic striking mechanism can be prevented to some extent by the dust seal 20, but the life of the dust seal 20 may be shortened depending on the use conditions of the hydraulic breaker 10, such as when dust is likely to scatter.

  On the other hand, as described above, a measure that increases the volume of the striking chamber to reduce the pressure change in the striking chamber and suppresses the entry of foreign matters such as dust into the hydraulic striking mechanism side is effective. The hydraulic breaker 10 is difficult to machine to expand the inner diameter of the striking chamber 2 because the cylinder 1 is an integral structure.

  Therefore, in the hydraulic breaker 10, an annular oil groove 30 formed in a plurality of stages in the cylinder axial direction is provided on the inner peripheral surface of the striking chamber 2 so that the grease is held in each oil groove 30. . Thus, according to the hydraulic breaker 10, grease is held in each oil groove 30, and the multi-stage oil groove 30 functions as a labyrinth seal by forming a wave shape as a whole. Can be retained. By allowing foreign matter such as dust that has entered during the crushing operation to stay in the multistage oil groove 30, entry of foreign matter to the cylinder liner side can be prevented or suppressed. In addition, since foreign matter can be prevented or suppressed from entering the hydraulic striking mechanism, wear at the contact portion between the piston 5 and the cylinder liners 23 and 24 can be suppressed.

  In particular, according to the hydraulic breaker 10, each oil groove 30 is provided with the inclined portion 31 on the side where foreign matter enters and the wall portion 33 orthogonal to the axial direction is formed on the hydraulic striking mechanism side. Foreign matter such as dust once retained in the oil groove 30 is unlikely to flow out toward the hydraulic striking mechanism side, and easily flows out toward the side where the foreign matter enters. Therefore, it is suitable for suppressing the flow of foreign matter to the hydraulic striking mechanism side, and for promoting the discharge of foreign matter to the front cap 4 side.

The hydraulic breaker according to the present invention is not limited to the above embodiment, and various modifications can be made without departing from the spirit of the present invention.
For example, in the above-described embodiment, the annular oil groove 30 has been described with an example in which the inclined portion 31 is provided on the side where the foreign substance enters and the wall surface portion 33 orthogonal to the axial direction is formed on the hydraulic striking mechanism side. However, the present invention is not limited to this, and various groove shapes can be adopted. However, in order to suppress the flow of the foreign matter to the hydraulic striking mechanism side and to promote the discharge of the foreign matter to the front cap 4 side, the inclined portion 31 is provided on the side where the foreign matter enters as an annular oil groove 30, It is preferable to form the wall surface portion 33 orthogonal to the axial direction on the hydraulic striking mechanism side.

DESCRIPTION OF SYMBOLS 1 Cylinder 2 Stroke chamber 3 Back head 4 Front cap 5 Piston 6 Control valve 7 Stroke control valve 9 Front holder 10 Hydraulic breaker 12 Chisel 20 Dust seal 21 Bolt 22 Washer 23 Cylinder liner (front side)
24 Cylinder liner (rear side)
30 Oil groove 31 Inclined portion 32 Bottom portion 33 Wall surface portion 41 Front head portion 42 Cylinder portion

Claims (2)

A front head portion into which a chisel is inserted from the front end side thereof and a cylinder portion into which a piston is slidably fitted via a cylinder liner are integrated, and the cylinder includes the front head portion. And a hydraulic breaker having a striking chamber in a portion between the cylinder portion and
The said cylinder has an annular | circular shaped oil groove formed in the inner peripheral surface of the said impact chamber over several steps in the axial direction of the said cylinder. The oil groove has an inclined portion formed on the front side in the axial direction, a wall surface portion formed on the rear side in the axial direction, and a bottom portion formed between the inclined portion and the wall surface portion,
The inclined portion is formed of an inclined surface formed so as to increase the inner diameter of the striking chamber from the axial front side toward the axial rear side, and the wall surface portion is formed of a wall surface orthogonal to the axial direction. The hydraulic breaker according to claim 1.

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