JP7529420B2 - Hydraulic Breaker - Google Patents

Description

The present invention relates to a hydraulic breaker.

Conventionally, split hydraulic breakers with a separate front head, cylinder, and back head are known (see, for example, Patent Document 1). This type of split hydraulic breaker has a cylinder in the axial center, with the front head connected to the front side of the cylinder and the back head connected to the rear side. The front head, cylinder, and back head are fastened to each other by long through bolts.

Also, in the case of a split-type hydraulic breaker, for example, a hydraulic breaker 100 shown in FIG. 4 is known in which a front head portion 101a and a cylinder portion 101b are integrated to form a cylinder 101, and a back head 103 is connected to the rear of this cylinder 101.
The type shown in the figure is called the flat top specification, in which a two-piece plate 160 is provided on both sides of the cylinder 101, and a bracket 170 for mounting a shovel is disposed on the rear end surface of the plate 160 that protrudes toward the rear end side of the back head 103, making it possible to hold the hydraulic breaker 100 from the rear (or from the top when mounted on the shovel).

The cylinder 101 and the back head 103 are fastened to each other by a bolt 121. A piston 105 is slidably fitted into the cylinder 101. A chisel 112 is inserted into the front head 102 from the tip side, and a striking chamber 111 is formed between the rear end side of the chisel 112 and the tip side of the piston 105.
A known hydraulic impact mechanism is provided in the cylinder 101, and the flow path of the pressure oil is switched by supplying pressure oil from a hydraulic supply source (not shown) so that the piston 105 can move forward and backward in the axial direction CL. The chisel 112 can move back and forth a predetermined distance in the axial direction by the impact of the piston 105.

JP 2008-114297 A

Here, in a hydraulic breaker, measures to increase the impact energy can be considered, first, by making the stroke of the piston longer, and, second, by increasing the pressure of the gas sealed in the back head.
However, in order to make the piston stroke longer, the machine length (the length in the axial direction of the hydraulic breaker) is increased, which is a trade-off in terms of making the structure small and compact. In particular, in the split-type hydraulic breaker 100 as described above, the cylinder 101 and the back head 103 are fastened to each other by the bolt 121.

Therefore, there is a potential problem that the extension of the machine length may cause twisting of the bolt 121 or loosening of the fastening of the bolt 121. In addition, the extension of the machine length may cause a problem that the handling operability becomes poor when the machine is attached to a shovel. In particular, such problems are more prominent in a hydraulic breaker in which the front head, the cylinder, and the back head are separated, as in the technology described in Patent Document 1.
On the other hand, while increasing the pressure of the gas sealed in the gas chamber of the back head is also an effective measure for increasing the impact energy, in the hydraulic breaker 100 having a separate back head 103 as described above, there is a risk of gas leakage from the separation portion between the cylinder and the back head due to the high pressure of the sealed gas.

In addition, the pressure of the gas (e.g., nitrogen gas) decreases with impact due to penetration into the oil film, and increasing the pressure increases the penetration into the oil film, making it more difficult to maintain the gas pressure. Furthermore, if the gas capacity is small, there is a problem that it is easily affected by changes in the outside air temperature, the temperature of the hydraulic breaker, and the temperature of the gas itself.
The present invention has been made in consideration of such problems, and has as its object to provide a hydraulic breaker that can increase the gas capacity of the gas chamber while having a small and compact structure.

In order to solve the above problems, a hydraulic breaker according to one embodiment of the present invention is characterized in that it comprises a breaker body having an integral structure including a front head portion into which a chisel is inserted from the tip side of the front head portion, a cylinder portion into which a piston is slidably fitted via a cylinder liner, and a back head portion within which a gas chamber is defined.
According to one aspect of the hydraulic breaker of the present invention, the breaker body has a front head section, a cylinder section, and a back head section which are integrated into one body, eliminating the need for long through bolts and enabling the gas capacity of the gas chamber to be increased while still maintaining a small and compact configuration.

In the hydraulic breaker according to one aspect of the present invention, it is preferable that the outer shape of the back head portion is wider than the outer shape of the cylinder portion. With this configuration, the back head portion of the breaker body is wider than the width of the cylinder portion, which is preferable in terms of significantly increasing the gas volume of the charged gas.
In addition, in a hydraulic breaker according to one aspect of the present invention, it is preferable that the breaker body has a cylinder section cover that covers the rear end opening of the cylinder section to prevent leakage of pressurized oil from within the cylinder section, and a back head section cover that covers the rear end opening of the back head section to prevent leakage of gas from within the back head section, and that the gas chamber is defined between the cylinder section cover and the back head section cover.

With this configuration, the gas chamber inside the back head portion is defined between the cylinder portion cover and the back head portion cover, so that the entire internal space of the rear back head portion can be used as a gas chamber, which is advantageous in enabling a significant increase in the gas volume of the enclosed gas.
Furthermore, by closing the front and rear of the gas chamber with a cylinder cover and a back head cover, respectively, the cooperation of these dedicated front and rear covers prevents leakage of pressurized oil from inside the cylinder section and prevents leakage of gas from inside the back head section. This is advantageous in that it increases the gas capacity of the gas chamber while maintaining a small and compact configuration without extending the length of the aircraft, and prevents or suppresses leakage of the sealed gas from the back head.

As described above, the present invention allows the gas volume of the gas chamber to be increased while maintaining a small, compact configuration.

1A and 1B are explanatory diagrams of a first embodiment of a hydraulic breaker according to one aspect of the present invention, in which FIG. 1A is a cross-sectional view taken along an axis line as viewed from the front, and FIG. 1B is a plan view. 2A to 2C are diagrams illustrating the breaker body of the hydraulic breaker in FIG. 1, in which FIG. 2A is a plan view, FIG. 2B is a cross-sectional view taken along the axis as viewed from behind, and FIG. 2C is a right side view of FIG. 5A and 5B are explanatory diagrams of a second embodiment of a hydraulic breaker according to an aspect of the present invention, in which FIG. 5A is a cross-sectional view taken along an axis line as viewed from behind, and FIG. 5B is a right side view of FIG. 5A. FIG. 1 is a diagram illustrating an example of a conventional split-type hydraulic breaker (with a split structure for the cylinder section and the back head section), in which (a) is a front view with the bracket attached, (b) is a plan view, and (c) is a cross-sectional view along the axis of the breaker body as viewed from behind with the bracket not attached. FIG. 5 is a diagram for explaining a seal structure at a joint between a cylinder portion and a back head portion in a conventional split-type hydraulic breaker (an enlarged view of a main portion of FIG. 4(c)).

Hereinafter, an embodiment of the present invention will be described with reference to the drawings. Note that the drawings are schematic. Therefore, it should be noted that the relationship and ratio between thickness and planar dimensions are different from the actual ones, and the drawings include parts where the relationship and ratio of dimensions are different from each other.
Furthermore, the embodiments described below are merely examples of devices and methods for embodying the technical ideas of the present invention, and the technical ideas of the present invention do not limit the materials, shapes, structures, arrangements, etc. of the components to the embodiments described below.

As shown in FIG. 1, this hydraulic breaker 10 has a breaker body 1 which is integrally formed with a front head portion 41 into which a chisel 12 is inserted from the tip side of the front head portion 41, a cylinder portion 42 into which a piston 5 is slidably fitted, and a back head portion 43 within which a gas chamber 60 is defined.
That is, the hydraulic breaker 10 of this embodiment has an integral structure in which the axial rear side of one breaker body 1 is the back head part 43, the front side of the cylinder part 42 is the front head part 41, and the part between the front head part 41 and the back head part 43 is the cylinder part 42. A flange part 1f is formed at the rear end of the breaker body 1, and a bracket 70 for mounting a shovel is directly attached to the rear end surface of the flange part 1f.

As shown in FIG. 2, the chisel 12 is inserted from the tip side into the front head portion 41, and the chisel 12 is held by an integral front bushing 3 on the same axis CL as the piston 5. The chisel 12 is restricted in its axial movement by a rod pin (not shown), and its reciprocating movement range is limited. Note that while the example in the figure shows an integral front bushing 3, this is not limiting, and the front bushing 3 may be made up of multiple bushings that support the front and rear of the axial direction, respectively.

The piston 5 is slidably fitted in the cylinder portion 42 via the cylinder liner 23. Between the front head portion 41 and the cylinder portion 42, 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 striking chamber 2 of this hydraulic breaker 10 is not processed to enlarge the inside diameter of the striking chamber 2 as a whole, and has approximately the same dimensions as the outer shape of the piston 5 with only a small gap therebetween.

The cylinder section 42 of the breaker body 1 is provided with a known hydraulic impact mechanism in which a switching control valve 6 constituting the hydraulic impact mechanism is arranged coaxially with the piston 5. By supplying pressure oil to the cylinder section 42 from a hydraulic supply source (not shown), the switching control valve 6 switches the flow path of the pressure oil, allowing the piston 5 to move forward and backward on the axis line CL. The chisel 12 can then be moved back and forth a predetermined distance in the axial direction by the impact of the piston 5.

The breaker body 1 of this embodiment has a cylinder cover 52 that covers the rear end opening of the cylinder 42 to prevent leakage of pressurized oil from within the cylinder 42, and a back head cover 53 that covers the rear end opening of the back head 43 to prevent leakage of gas from within the gas chamber 60 of the back head 43. A gas seal 90 is provided between the cylinder 1 and the piston 5, and the cylinder cover 52 is fixed to the rear end surface of the cylinder 42 by multiple bolts 51 (four in this example).

2, the back head section 43 is formed with a width wider than that of the cylinder section 42, and a gas chamber 60 is defined between the cylinder section cover 52 and the back head section cover 53. In this embodiment, the rear end surface of the back head section cover 53 is flush with the rear end surface of the breaker body 1. The rear end surface of the back head section cover 53 may be formed closer to the tip side than the position flush with the rear end surface of the breaker body 1.

As shown in Fig. 1C, the back head cover 53 is circular so as to cover the rear end surface of the widened back head portion 43, and an O-ring seal portion 80 is provided around the periphery. Appropriate locations around the periphery of the back head cover 53 are fixed by a plurality of bolts 54 (eight locations in this example). The heads of the bolts 54 are embedded in recessed steps formed in the back head cover 53 so as not to protrude rearward.
The back head portion 43 has a communication hole 61 formed in a position facing the side surface of the cylinder portion cover 52, the communication hole 61 communicating with the gas chamber 60, and a gas filling valve 62 is attached to this communication hole 61.

Next, the operation and effects of the hydraulic breaker 10 of this embodiment will be described.
When the hydraulic breaker 10 of this embodiment is driven, pressure oil is supplied from a hydraulic supply source (not shown) to the hydraulic impact mechanism of the cylinder section 42. As a result, the flow path of the pressure oil is switched by the hydraulic impact mechanism, the piston 5 moves forward and backward on the axis line CL, and the chisel 12 reciprocates a predetermined distance in the axial direction due to the impact of the piston 5, thereby performing the desired impact operation.

The hydraulic breaker 10 of this embodiment has a breaker body 1 which is integrally formed with the front head portion 41 into which the chisel 12 is inserted from the tip side, the cylinder portion 42 into which the piston 5 is slidably fitted via the cylinder liner 23, and the back head portion 43, so that a long through bolt is not required and problems with twisting and loosening of the bolt can be eliminated. Also, the breaker body 1 can be constructed small and compact.
In the hydraulic breaker 10 of this embodiment, the bracket 70 for mounting the shovel is directly attached to the rear end surface of the flange portion 1f of the breaker body 1. Therefore, compared to the hydraulic breaker 100 shown in Figure 4, parts such as the bolt 121 for fastening the back head 103 and the two-piece plate 160 are not required, and the breaker body 1 can be made smaller and more compact.

In particular, in the hydraulic breaker 10 of this embodiment, the rear end surface of the back head cover 53 is flush with the rear end surface of the flange portion 1f of the breaker body 1 or is closer to the tip side than flush with the rear end surface. This is suitable for making the axial length (machine length) of the hydraulic breaker compact in a configuration in which a bracket 70 for mounting a shovel is attached to the rear end surface of the breaker body 1. Since the machine length affects the handling operability when mounted on the shovel, a shorter machine length and a center of gravity closer to the shovel mounting portion provide better handling operability.

Furthermore, according to the hydraulic breaker 10 of this embodiment, the back head section 43 is formed with a width greater than that of the cylinder section 42, and the gas chamber 60 inside the back head section 43 is defined between the cylinder section cover 52 and the back head section cover 53, so that the entire internal space of the back head section 43 rearward of the cylinder section 42 is made into the gas chamber 60, making it possible to significantly increase the gas capacity.
Furthermore, according to the hydraulic breaker 10 of this embodiment, the front and rear of the gas chamber 60 are closed by the cylinder cover 52 and the back head cover 53, respectively, which prevents leakage of pressurized oil from inside the cylinder section 42 and prevents leakage of gas from inside the gas chamber 60 of the back head section 43. Therefore, according to the hydraulic breaker 10 of this embodiment, it is possible to significantly increase the gas capacity of the gas chamber 60 while shortening the machine length to achieve a small and compact configuration.

Here, in the hydraulic breaker 100 shown in FIG. 4, as shown in FIG. 4(c), the back head 103 is fixed to the cylinder 101 by the fastening bolts 121. Therefore, the back head 103 and the fastening bolts 121 not only have the function of fixing the back head 103, but also have the function of withstanding pressure against the pressure of the pressurized oil on the piston 105 side and the gas pressure in the gas chamber 160.
In contrast, according to the hydraulic breaker 10 of this embodiment, the front side of the gas chamber 60 is closed by a dedicated cylinder cover 52, and the rear side of the gas chamber 60 is closed by a dedicated back head cover 53, so that a so-called "division of roles" is achieved, whereby the cylinder cover 52 exclusively bears the pressure of the pressurized oil on the piston 5 side, and the back head cover 53 exclusively bears the gas pressure of the gas chamber 60.

In other words, in the hydraulic breaker 100 shown in FIG. 4, the sealing of the gas chamber in the back head 103 is provided by an O-ring seal 180 provided at the spigot portion at the boundary between the back head 103 and the cylinder 101, and a gas seal 190 provided between the cylinder 101 and the piston 105, as shown in an enlarged view of the main parts in FIG.
Here, if we focus on the O-ring seal portion 180, if a biased external force acts on this seal portion 180, its sealing function will be reduced. However, in this hydraulic breaker 100, the back head 103 and the cylinder 101 are fastened with bolts 121. Therefore, if an external force in the twisting direction acts on the back head 103, this is transmitted to the seal portion 180, and the biased external force acts on the seal portion 180, reducing its sealing function.

In contrast, the hydraulic breaker 10 of this embodiment does not have a back head to begin with, and instead has a structure in which the gas chamber 60 is closed by the back head cover 53. As described above, the back head cover 53 is fixed to the breaker body 1 by a plurality of bolts 54, so that no external force in the twisting direction is applied to the seal portion 80 of the back head cover 53.
Therefore, the sealing function of the seal portion 80 of the back head cover 53 is stable, and as a result, gas leakage can be prevented or suppressed. In other words, the above-mentioned "division of roles" allows the dedicated back head cover 53 to specialize in the pressure resistance function against the gas pressure of the gas chamber 60 when the enclosed gas is pressurized. This makes it possible to set the gas pressure higher than before.

The dedicated cylinder cover 52 is also fixed to a position within the gas chamber 60 of the breaker body 1 by multiple bolts 51, so that it receives the pressure of the pressurized oil on the piston 105 side while preventing the gas from penetrating into the oil film due to the high pressure of the enclosed gas (e.g., nitrogen gas), and therefore has its own role as a dedicated part, which is more suitable for preventing or suppressing gas leakage from the gas chamber 60 than the hydraulic breaker 100 shown in Figure 4. Therefore, it can be said that this structure is excellent in terms of shortening the machine length and achieving a small and compact configuration while significantly increasing the gas capacity of the gas chamber 60 to more reliably perform its function.

In particular, as shown in FIG. 2(b), the outer shape of the back head portion 43 is wider than the outer shape of the cylinder portion 42, and as shown in FIG. 2(c), a circular back head cover 53 is provided to cover the rear end face of the wider back head portion 43. This significantly increases the gas capacity of the gas chamber 60, making it more reliable in functioning, while shortening the machine length to make it compact and compact, making it an excellent structure for use as a pressure-resistant cover for high-pressure gas.

In this way, according to the hydraulic breaker 10 of this embodiment, the gas chamber 60 is defined between the dedicated cylinder cover 52 and the dedicated back head cover 53, and the cooperation between these two covers 52, 53 has an effect that cannot be achieved with the hydraulic breaker 100 shown in Figure 4, and this greatly increases the gas capacity of the gas chamber 60, allowing it to perform its function more reliably while shortening the machine length and achieving a small, compact configuration.

As described above, according to the hydraulic breaker 10 of this embodiment, while maintaining a small and compact configuration without increasing the length of the breaker, it is possible to increase the gas capacity of the gas chamber and prevent or suppress leakage of the sealed gas from the back head.
The hydraulic breaker according to the present invention is not limited to the above-mentioned embodiment, and various modifications are possible without departing from the spirit of the present invention. For example, in the above-mentioned first embodiment, the switching control valve 6 constituting the hydraulic impact mechanism is arranged coaxially with the piston 5, but the present invention is not limited to this, and the switching control valve 6 constituting the hydraulic impact mechanism can be formed non-coaxially with the piston 5, as shown in the second embodiment in FIG.

Reference Signs List 1 Breaker body 2 Striking chamber 3 Front bush 5 Piston 6 Control valve 10 Hydraulic breaker 12 Chisel 23 Cylinder liner 41 Front head portion 42 Cylinder portion 43 Back head portion 52 Cylinder portion cover 53 Back head portion cover 60 Gas chamber 61 Communication hole 62 Gas charging valve 70 Bracket CL Axis

Claims (6)

The breaker body is provided with a front head portion into which a chisel is inserted from the tip side of the front head portion, a cylinder portion into which a piston is slidably fitted via a cylinder liner, and a back head portion in which a gas chamber is defined, the front head portion being integrally constructed with the cylinder portion ,
the breaker body includes a cylinder cover that covers a rear end opening of the cylinder portion so as to prevent leakage of pressure oil from within the cylinder portion, and a back head cover that covers a rear end opening of the back head portion so as to prevent leakage of gas from within the back head portion,
The gas chamber is defined between the cylinder portion cover and the back head portion cover,
A bracket for mounting a shovel is directly attached to the rear end surface of the breaker body,
A hydraulic breaker characterized in that a rear end surface of the back head cover is flush with a rear end surface of the breaker body or is closer to the tip side than the flush position . The breaker body is provided with a front head portion into which a chisel is inserted from the tip side of the breaker body, a cylinder portion into which a piston is slidably fitted, and a back head portion in which a gas chamber is defined, the front head portion being integrally constructed,
the breaker body includes a cylinder cover that covers a rear end opening of the cylinder portion so as to prevent leakage of pressure oil from within the cylinder portion, and a back head cover that covers a rear end opening of the back head portion so as to prevent leakage of gas from within the back head portion,
The gas chamber is defined between the cylinder portion cover and the back head portion cover,
A hydraulic breaker characterized in that the cylinder cover is fixed to the breaker body . 3. The hydraulic breaker according to claim 2, further comprising a cylinder liner disposed between the cylinder portion and the piston. A bracket for mounting a shovel is directly attached to the rear end surface of the breaker body,
4. The hydraulic breaker according to claim 2, wherein the rear end surface of the back head cover is flush with the rear end surface of the breaker body or is closer to the tip side than the flush position. 5. The hydraulic breaker according to claim 1, wherein the outer shape of the back head portion is formed to be wider than the outer shape of the cylinder portion. 6. A hydraulic breaker according to claim 1, wherein a communication hole communicating with the gas chamber is formed at a position opposite to a side surface of the cylinder cover, and a gas filling valve is attached to the communication hole.

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