JP2014176945A - Hydraulic breaker - Google Patents

Abstract

PROBLEM TO BE SOLVED: To prevent or suppress abrasion of a cylinder and a cylinder liner in an integral-type hydraulic breaker in which a front head part and a cylinder part have an integral structure.SOLUTION: A hydraulic breaker 10 comprises a cylinder 1 in which a front head part 41, to which a chisel 12 is attached by insertion thereof from a tip side of the front head part itself, and a cylinder part 42, into which a piston 5 is slidably fitted via a cylinder liner 23, have an integral structure. A washer 22 made from a steel of a low hardness, which is a steel type different from that of the cylinder 1 and the cylinder liner 23, is inserted between surfaces of the cylinder 1 and the cylinder liner 23, which face each other in an axial direction CL, in a front part of the cylinder liner 23.

Description

  The present invention relates to a hydraulic breaker having 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, and in particular, prevents wear of the cylinder and the cylinder liner. Or it relates to the technology to suppress.

Conventionally, a split type hydraulic breaker in which a front head and a cylinder are divided is known (see, for example, Patent Document 1).
For example, a hydraulic breaker of this type has a cylinder 101 at the center in the axial direction CL as in the hydraulic breaker 100 shown in FIG. 4, and a front head 102 is connected to the front side of the cylinder 101. A back head 103 is connected to the rear side. 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 chisel 112 is inserted into the front head 102 from the front end side, and 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 cylinder 101 is provided with a known hydraulic striking mechanism, and by supplying pressure oil from a hydraulic supply source (not shown), the flow path of the pressure oil is switched, and the piston 105 can move forward and backward in the axial direction CL. Yes. The chisel 112 can reciprocate a predetermined distance in the axial direction by striking the piston 105.

JP 2008-114297 A

  Incidentally, in the split hydraulic breaker 100 as described above, the front head 102, the cylinder 101, and the back head 103 are fastened to each other by the long through bolts 121. There is a potential problem that the tightening of the through bolt 121 is loosened.

Therefore, 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 through bolt. As shown in FIG. 3, the hydraulic breaker having an integral cylinder structure includes a front head portion 41 into which the chisel 12 is inserted from the front end side thereof, and a piston 5 through the cylinder liners 23 and 24. It has the cylinder 1 which made the cylinder part 42 slidably fitted into an integral structure. The back head 3 is connected to the rear side of the cylinder 1 by a short bolt 21.
If the hydraulic breaker has an integrated cylinder structure, the cylinder 1 and the back head 3 can be fastened to each other with a short bolt 21, so that a long through bolt is unnecessary, and the problem of twisting or loosening of the bolt is eliminated. Can be resolved.

  Here, in the hydraulic breaker of this type of integrated cylinder structure, the integrated cylinder 1 is long, and the striking chamber 2 is located in the vicinity of the central portion in the axial direction of the cylinder 1. Therefore, the piston 5 is slid through the cylinder liners 23 and 24 in order to process the striking chamber 2 and the like located near the center from both ends of the long cylinder 1. In the hydraulic breaker having an integrated cylinder structure using the cylinder liners 23 and 24, in the example shown in FIG. 3, the cylinder liner 23 is directly brought into contact with the cylinder 1 by a surface (refer to reference numeral D) facing in the axial direction CL. It is assembled like this. The cylinder liner 23 may be equipped with a seal part such as an O-ring.

  However, when the cylinder liner 23 is assembled to the cylinder 1 such that the cylinder liner 23 is in direct contact with the opposite surface in the axial direction CL, the cylinder 1 and the cylinder liner 23 are in direct contact with each other in the axial direction CL. Therefore, due to the impact force in the axial direction CL caused by the impact of the hydraulic breaker, wear on the opposing surfaces in the axial direction CL of both the cylinder 1 and the cylinder liner 23 proceeds, and troublesome repairs may occur during maintenance of the hydraulic breaker, There is a possibility that expensive parts such as 1 and the cylinder liner 23 may be replaced.

For such a problem, although a cushioning material such as urethane resin may be interposed between the surfaces facing each other in the axial direction CL of both the cylinder 1 and the cylinder liner 23, the interposed member is made of steel. Otherwise, sufficient strength cannot be ensured.
Accordingly, the present invention has been made paying attention to such problems, and includes a cylinder in which a front head portion and a cylinder portion are integrated, and a piston slides in the cylinder portion via a cylinder liner. An object of the present invention is to provide a hydraulic breaker that can prevent or suppress wear of the axially opposed surfaces of both the cylinder and the cylinder liner in the fitted hydraulic breaker.

  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 including a cylinder having an integral structure, wherein the cylinder and the cylinder liner are disposed between the front surfaces of the cylinder liner and the surfaces of the cylinder and the cylinder liner facing each other in the axial direction. It is characterized in that a steel washer having a different hardness from that of the material and having a low hardness is interposed.

  According to the hydraulic breaker according to one aspect of the present invention, in the hydraulic breaker including a cylinder in which the front head portion and the cylinder portion are integrated, the front portion of the cylinder liner and the cylinder and the cylinder liner are in the axial direction. Between the opposing surfaces, the material of the cylinder and cylinder liner is different from the material of the steel and a low-hardness steel washer is interposed, so when an impact force in the axial direction due to the impact of the hydraulic breaker is applied Compared to the axially opposed surfaces of both the cylinder and the cylinder liner, the interposed washer first wears to function as a consumable part. Therefore, it is possible to prevent or suppress wear on the surfaces of the cylinder and the cylinder liner that face each other in the axial direction. Such a steel washer is simple and inexpensive to manufacture, and does not require any special seals. Therefore, troublesome repairs during the maintenance of the hydraulic breaker do not occur, and the cylinder or cylinder liner It is not necessary to replace expensive parts such as. In addition, when the hydraulic breaker is regularly maintained, only the washer may be replaced as a consumable part.

  Here, in the hydraulic breaker according to one aspect of the present invention, the washer preferably has an oil groove on at least one of a contact surface with the cylinder, a contact surface with the cylinder liner, and an outer peripheral surface thereof. . With such a configuration, by attaching a washer having an oil groove at a position in front of the cylinder liner, the oil groove can serve as a grease reservoir. Therefore, it is possible to maintain lubricity, suppress wear of the washer itself, and improve durability. Further, foreign matter such as dust in the working atmosphere of the hydraulic breaker and wear powder of built-in parts can be retained (dust pocket) in the oil groove (grease reservoir). Therefore, it is more suitable for suppressing wear on the surfaces and other contact portions facing each other in the axial direction of both the cylinder and the cylinder liner.

  As described above, according to the present invention, in the hydraulic breaker having an integrated cylinder structure in which the front head portion and the cylinder portion are integrated, it is possible to prevent wear of surfaces facing each other in the axial direction of both the cylinder and the cylinder liner. Can be 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. Note that the intrusion path of foreign matter such as dust is also indicated by arrows. It is an enlarged view ((a)) of the washer interposed in the principal part (A part) in FIG. 1, and B arrow view ((b)) in the figure (a). It is a figure explaining an example of the hydraulic breaker of an integrated cylinder structure, The figure has shown the hydraulic breaker in the cross section containing the axis line. Note that the intrusion path of foreign matter such as dust is also indicated by arrows. 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.

Hereinafter, an embodiment of the present invention will be described with reference to the drawings as appropriate. Note that portions corresponding to one example (FIG. 3) of the hydraulic breaker having the integrated cylinder structure described above are denoted by the same reference numerals and described.
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, in the hydraulic breaker 10, the rear side in the axial direction of the cylinder 1 is a cylinder part 42, and the front side of the cylinder part 42 is integrally formed with the cylinder part 42 as a front head part 41. 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.

  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. Although having substantially the same size, oil grooves 30 formed in multiple stages in the axial direction of the cylinder 1 are formed on the inner wall surface of the striking chamber 2. The multi-stage (in this example, five stages) oil grooves 30 are machined at equal intervals in the axial direction. Each oil groove 30 has a substantially trapezoidal shape in cross-sectional view, and has an annular shape over the circumferential direction. The plurality of oil grooves 30 are provided adjacent to each other so as to function as a labyrinth seal by mutual cooperation, so that the oil grooves 30 are formed so as to exhibit a corrugated shape as a whole in a sectional view along the axial direction. ing.

  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.

Here, in the hydraulic breaker 10, the cylinder liner 23 is fitted on the inner surface of the front end of the cylinder portion 42 via the washer 22. In other words, the washer 22 is interposed between the surfaces where the cylinder 1 and the cylinder liner 23 face each other in the axial direction CL. A dust seal 20 is provided on the inner surface of the tip of the cylinder liner 23 to prevent foreign matters 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. Yes. Thereby, the dust seal 20 installed on the front side of the cylinder portion 42 prevents foreign matter from entering the hydraulic striking mechanism.
The washer 22 is an annular plate member made of low-hardness steel, which is different from the material of the cylinder 1 and the cylinder liner 23.

  In addition, as shown in an enlarged view in FIG. 2, the washer 22 has oil on all surfaces of the contact surface 22 a with the cylinder 1, the contact surface 22 b with the cylinder liner 23, and the outer peripheral surface 22 c in the example of this embodiment. A groove 31 is formed. On the contact surface 22a with the cylinder 1 and the contact surface 22b with the cylinder liner 23, two oil grooves 31 that are substantially equally spaced apart in the radial direction and formed in an annular shape along the circumferential direction are respectively provided. Is provided. Further, on the outer peripheral surface 22c of the washer 22, a single oil groove 31 is formed in an annular shape along the peripheral surface at a central position in the axial direction. Each of the oil grooves 31 is processed by a groove having a V-shaped cross section. The outer peripheral surface 22c of the washer 22 is provided with chamfered portions 32 formed by inclined surfaces of approximately 45 ° at the respective corner portions in the front and rear directions in the axial direction over the entire circumference.

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.
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 through the cylinder liners 23 and 24. Since the cylinder 1 is provided, a long through bolt is unnecessary, and the problem of twisting or loosening of the bolt 21 can be solved.

  In particular, according to the hydraulic breaker 10, the hydraulic breaker includes the cylinder 1 in which the front head portion 41 and the cylinder portion 42 are integrally formed. The hydraulic breaker 10 is a front portion of the cylinder liner 23 and includes the cylinder 1 and the cylinder liner 23. Between the surfaces facing each other in the axial direction CL, a steel washer 22 having a different steel type from the material of the cylinder 1 and the cylinder liner 23 and having a low hardness is interposed. When an impact force in the direction CL is applied, the interposed washer 22 is first worn out as compared with the opposed surfaces of the cylinder 1 and the cylinder liner 23 in the axial direction CL, and the washer 22 is used as a consumable part. Can function. Therefore, it is possible to prevent or suppress wear on the surfaces of the cylinder 1 and the cylinder liner 23 facing each other in the axial direction CL.

  If the steel washer 22 as shown in FIG. 2 is used, the manufacturing process is simple, inexpensive, and no special seal is required, so that troublesome repairs during the maintenance of the hydraulic breaker 10 may occur. In addition, it is not necessary to replace expensive parts such as the cylinder 1 and the cylinder liner 23. Further, when the hydraulic breaker 10 is regularly maintained, only the washer 22 may be replaced as a consumable part.

  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 in operation, the intrusion path of foreign matter such as dust into the hydraulic breaker 10 is mainly entered from the gap between the chisel 12 and the front cap 4 through the hydraulic impact mechanism. 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.

  With respect to such a problem, the washer 22 has oil grooves 31 on all of the contact surface 22a with the cylinder 1, the contact surface 22b with the cylinder liner 23 and the outer peripheral surface 22c. By attaching the washer 22 having the oil groove 31 at a position in front of the oil groove 31, the oil groove 31 can serve as a grease reservoir. Therefore, it is possible to maintain the lubricity and suppress the wear of the washer 22 itself to improve the durability. In addition, foreign matter such as dust in the working atmosphere of the hydraulic breaker 10 and wear powder of built-in parts is removed from the oil groove (grease It can be retained (dust pocket) in the reservoir 31. Therefore, it is more suitable for suppressing wear on the axially opposing surfaces of both the cylinder 1 and the cylinder liner 23 and other contact portions.

  Furthermore, according to the hydraulic breaker 10, the oil grooves 30 formed in a plurality of stages in the cylinder axial direction are provided on the inner peripheral surface of the striking chamber 2, so that the grease is held in each oil groove 30. At the same time, the multi-stage oil groove 30 functions as a labyrinth seal by forming a wave shape as a whole, and foreign substances such as dust can be retained in the oil groove 30, and foreign substances such as dust that flowed in during the crushing operation are multi-staged. By staying in the oil groove 30, it is possible to prevent or suppress entry of foreign matter into the cylinder liner 23 side. Therefore, the entry of foreign matter to the hydraulic striking mechanism side is prevented or suppressed, which is more suitable for suppressing wear at the contact portion between the piston 5 and the cylinder liners 23 and 24.

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 washer 22 is described as an example in which the oil groove 31 is formed on all surfaces of the contact surface 22a with the cylinder 1, the contact surface 22b with the cylinder liner 23, and the outer peripheral surface 22c. However, the present invention is not limited thereto, and the oil groove 31 may not be provided in the washer 22, and at least one of the contact surface 22a with the cylinder 1, the contact surface 22b with the cylinder liner 23, and the outer peripheral surface 22c itself. The oil groove 31 may be provided. However, the lubricity is maintained and wear of the washer 22 itself is suppressed to improve durability, and foreign matters such as dust in the working atmosphere of the hydraulic breaker 10 and wear powder of built-in parts are retained in the oil groove 31. Above, it is preferable to form the oil grooves 31 on all surfaces of the contact surface 22a with the cylinder 1, the contact surface 22b with the cylinder liner 23, and the outer peripheral surface 22c as in the above embodiment.

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 wall surface) 31 Oil groove (Washer) groove 32 (Washer) chamfered part 41 Front head part 42 Cylinder part

Claims (2)

A hydraulic breaker comprising a cylinder in which a front head portion into which a chisel is inserted from the front end side of itself and a cylinder portion into which a piston is slidably fitted via a cylinder liner are integrated.
A steel washer having a steel type different from the material of the cylinder and the cylinder liner and having a low hardness between the surfaces of the front portion of the cylinder liner and the cylinder and the cylinder liner facing each other in the axial direction. A hydraulic breaker characterized by being interposed.   2. The hydraulic breaker according to claim 1, wherein the washer has an oil groove on at least one of a contact surface with the cylinder, a contact surface with the cylinder liner, and an outer peripheral surface thereof.

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