JP2009144335A - Working device of construction machinery - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a working device of construction machinery, which can suppress resonance inside a front structure without infilling a damping material and a sound absorbing material. <P>SOLUTION: This working device of the construction machinery is equipped with the front structure 5 which is composed of a hollow structure, which is provided in a vertically revolvable manner in a revolving superstructure 2 as a vehicle body of a hydraulic excavator, and inside which a bulkhead 12 for increasing strength is provided. A partition plate 20 for reducing noises is provided in a prescribed position based on a standing wave 21 generating along with the drive of the hydraulic excavator, in a closed space section 18 formed of the bulkhead 12. <P>COPYRIGHT: (C)2009,JPO&INPIT

Description

  The present invention relates to a working device for a construction machine that reduces vibrations generated by a hollow structure and noise caused by resonance during operation of the construction machine.

As a working device of this type of construction machine, there is one shown in Patent Document 1. Patent Document 1 discloses a front structure of a hydraulic excavator that is a construction machine. Examples of the front structure include an arm made of a hollow structure and a boom. Inside these arms and booms, there are partition plates as strength members, that is, partition walls, and a sound absorbing material such as damping material or urethane is filled in the substantially central portion in the longitudinal direction formed by the partition walls. . Thereby, the vibration generated inside the arm and the boom can be reduced without filling the entire area of the arm and the boom with the damping material and the sound absorbing material, so that the resonance can be suppressed. The noise generated from the is reduced.
JP 2002-274441 A

  However, in the conventional construction machine working apparatus as shown in Patent Document 1 described above, in order to reduce noise generated from an arm, a boom, or the like, which is a front structure of a hydraulic excavator, a damping material, a sound absorbing material, or the like is used. In addition to the need for members, there is a problem in that the number of work steps required for manufacturing the front structure increases due to the complicated work of filling the inside of the hollow structure with the damping material and the sound absorbing material.

  The present invention has been made in consideration of the actual state of the prior art as described above, and its purpose is construction that can suppress resonance inside the front structure without being filled with a damping material or a sound absorbing material. It is to provide a working device for a machine.

  In order to achieve this object, the present invention is a construction machine comprising a front structure having a partition wall which is formed of a hollow structure and is pivotally provided in a vehicle body of the construction machine so as to be pivotable in the vertical direction. In this working apparatus, a noise reduction partition plate for partitioning the closed space portion is provided at a predetermined position in the closed space portion formed by the partition wall based on a standing wave generated when the construction machine is driven. It is characterized by that.

  The inventors of the present invention have the above-mentioned noise generated from the front structure when vibrations generated during the operation of the construction machine having the front structure, for example, the operation of an engine, a pump, a cooler, etc. are propagated to the front structure. These frequencies and the natural frequency of the enclosed space inside the hollow structure of the front structure coincide with each other, so that a resonance state is reached, and a node where the amplitude of the sound pressure level is maximum and a node where the amplitude is minimum are obtained. Focusing on the fact that the standing wave that is generated in the enclosed space inside the front structure is the cause, the standing wave generated inside the front structure during the operation of the construction machine is predicted in advance by calculation and analysis. Since the partition plate for noise reduction for partitioning the inside of the enclosed space portion is provided at a predetermined position based on the predicted standing wave, the area of the enclosed space in the enclosed space portion can be changed. It is possible to change the resonance frequency to produce a standing wave. Thereby, the vibration inside the front structure can be reduced and the resonance inside the front structure can be suppressed without filling the inside of the front structure with the damping material or the sound absorbing material.

  In the present invention, the front structure may be a box-shaped hollow structure including an upper plate, a lower plate, and left and right side plates, and the partition wall may include a plurality of internal spaces of the hollow structure. It is characterized by being provided so as to be divided into closed spaces.

  Furthermore, the present invention is characterized in that, in the above invention, the partition plate is provided orthogonal to the longitudinal direction of the front structure. In the present invention configured as described above, the strength of the front structure can be further increased by the partition plate.

  Further, in the present invention according to the above invention, the cab is provided in the vehicle body, the front structure is provided so as to rotate in the vicinity of a side surface of the cab, and the partition plate It is provided in the closed space that passes through the side of the cab and the vicinity of the side when the structure is rotated.

  Furthermore, the present invention is characterized in that, in the above invention, the partition also serves as the partition plate. The present invention configured as described above can reduce the number of partition plates.

  Moreover, the present invention is characterized in that, in the above-mentioned invention, the partition plate is arranged at a position corresponding to a node of a standing wave generated in the hollow structure or an antinode.

  The present invention provides a noise reduction partition plate that is provided in a closed space portion inside a front structure of a construction machine and partitions the closed space portion at a predetermined position based on a standing wave generated when the construction machine is driven. Thus, the partition plate can change the region of the closed space in the closed space portion described above, thereby changing the resonance frequency that generates the standing wave. Resonance inside the front structure can be suppressed without filling a vibration material or a sound absorbing material. Therefore, the conventional work of filling the inside of the front structure with the vibration damping material and the sound absorbing material is not required, and the work of installing the partition plate inside the front structure is a process of manufacturing the front structure. Therefore, the number of work steps required for manufacturing the front structure can be reduced as compared with the prior art.

  The best mode for carrying out the construction machine working apparatus according to the present invention will be described below with reference to the drawings.

  FIG. 1 is a side view of a hydraulic excavator cited as an example of a construction machine provided with an embodiment of a construction machine working apparatus according to the present invention. FIG. 2 is a side view of a boom constituting the working device according to the present embodiment provided in the hydraulic excavator shown in FIG. 1, and FIG. 3 is a cross-sectional view of the main part as viewed from the arrow A in FIG. FIG. 4 is a diagram illustrating an example of an installation position of a noise reduction partition plate provided in the present embodiment, and FIG. 5 is a diagram illustrating a changed standing wave obtained in the present embodiment.

  As shown in FIG. 1, the construction machine provided with the present embodiment, for example, a hydraulic excavator, turns as a vehicle body having a traveling body 1 and a cab 3, a counterweight 4, and the like disposed on the traveling body 1. A body 2 and a front structure 5 provided on the swivel body 2 so as to be rotatable in the vertical direction are provided. The front structure 5 includes a boom 6 which will be described later and an arm 7 which is rotatably provided on the boom 6, and a bucket 8 as a work tool is rotatably provided on the arm 7. The front structure 5 is a hollow structure. Each of the aforementioned boom 6, arm 7, and bucket 8 can be rotated by a telescopic operation of a hydraulic actuator, that is, a boom cylinder 9, an arm cylinder 10, and a bucket cylinder 11. The front structure 5 having the boom 6 and the arm 7 is provided with a partition wall 12 as a strength member that increases the strength of the front structure 5 and closes the internal space.

  In addition, the boom 6 is provided in the center front part of the turning body 2 by making the vicinity of the side surface of the cab 3 into a rotation range.

  The principal part of this embodiment is demonstrated with the boom 6 shown to FIG. As shown in FIGS. 2 and 3, the boom 6 is provided with a boss 13 through which a foot pin (not shown) is inserted on the base end side, and the foot pin is inserted into the boss 13 so that the revolving body 2 can be rotated. Connected to Further, the boom 6 is formed as a box-shaped hollow structure by an upper plate 6a, a lower plate 6b and left and right side plates 6c whose base end portions are fixed to the boss 13, and in the inside thereof, 2 as a strength member described above is formed. A single partition 12 is provided. The partition 12 divides the internal space of the hollow structure into a plurality of closed space portions 17, closed space portions 18, and closed space portions 19. The aforementioned closed space portion 17 forms a foot pin side portion 14 located in the vicinity of the boss 13, and the aforementioned closed space 18 is located at the center of the boom 6 and has an intermediate portion 15 having an attachment portion for the boom cylinder 9. The above-described closed space portion 19 is formed at the tip end of the boom 6 and forms a tip end portion 16 having an attachment portion of the arm 7.

  Further, as illustrated in FIG. 3, the intermediate portion 15 of the boom 6 has a hollow structure having a square cross-sectional portion 18 a by an upper plate 6 a, a lower plate 6 b, and two side plates 6 c. The above-described two partition walls 12 are made of, for example, a rectangular steel plate made of the same material as the upper plate 6a, the lower plate 6b, and the two side plates 6c forming the hollow structure, and the extending direction (longitudinal direction) of the boom 6 is the same. The four sides are welded to the upper plate 6a, the lower plate 6b, and the two side plates 6c so as to be perpendicular to (direction) (see FIG. 2).

  In addition, the above-described closed space portions 17, 18, and 19 usually have their own resonances depending on the box shape of the respective closed space portions, the density of a substance (for example, air) contained in these closed space portions 17, 18, and 19, and the like. Have a frequency. For example, when vibrations caused by operations of an engine, a pump, a cooler, etc. (not shown) are transmitted to the boom 6 and are in a resonance state by matching with the inherent resonance frequency of the closed space portion 18 of the intermediate portion 15 described above, for example, As shown in FIG. 4, the standing wave 21 having the antinode 21b having the maximum amplitude of the sound pressure level and the node 21a having the minimum amplitude is generated, and a large noise is generated.

  In order to reduce the noise generated by the standing wave 21, particularly in the present embodiment, the hydraulic excavator is driven in the closed space 18 of the intermediate portion 15 formed by the partition wall 12 as a strength member, for example, as described above. In consideration of the standing wave 21 generated during operation of the engine, pump, cooler, etc., a noise reduction partition plate 20 for partitioning the closed space 18 is provided at a predetermined position based on the standing wave 21. . For example, the partition plate 20 is made of the same material as the upper plate 6a, the lower plate 6b, the two side plates 6c of the boom 6, and the two partition walls 12. Further, as shown in FIG. 2, the partition plate 20 divides the aforementioned closed space portion 18 into a first closed space portion 18 b and a second closed space portion 18 c.

  Further, the partition plate 20 is provided separately from the partition wall 12 of the boom 6, and is provided orthogonal to the longitudinal direction of the boom 6.

The installation position of the partition plate 20 is based on the standing wave as described above, and is provided, for example, at a position that becomes the node 21a of the standing wave 21 as shown in FIGS. In addition, you may make it provide the partition plate 20 in the position of the antinode 21b of the standing wave 21 shown in FIG. The installation position of the partition plate 20 is determined as described below in consideration of the wavelength λ of the standing wave 21 generated in the closed space portion 18 of the intermediate portion 15 described above. For example, if a standing wave 21 having a frequency f is generated in the closed space portion 18 of the intermediate portion 15 and the sound velocity in the closed space 18 is predicted to be c by analysis or calculation, the wavelength λ of the standing wave is ,
Standing wave wavelength λ = sonic velocity c in closed space 18 / frequency f of standing wave 21
It is calculated by the following formula. And, as shown in FIG. 4, when the partition plate 20 is provided at the node 21a of the standing wave 21 that is separated from the partition wall 12 on the right side in the figure by the installation distance L in the longitudinal direction of the boom 6, for example, The installation distance L of the partition plate 20 is
In L = λ × n / 4, n = 1,
L = λ × 1/4
It is calculated by the following formula. In addition, when installing in the antinode 21b of the standing wave 21, the installation position of the partition plate 20 shall be n = 2,
What is necessary is just to obtain | require by the type | formula of L = (lambda) * 2/4 = (lambda) * 1/2.

  The aforementioned partition plate 20 is provided in the closed space portion 18 of the intermediate portion 15 by the following procedure.

  First, the standing wave 21 generated in the intermediate portion 15 and the sound velocity c in the intermediate portion 15 are predicted by the above-described analysis and calculation due to vibrations generated as the hydraulic excavator is driven. Next, the partition plate 20 is fixed to the upper plate 6a, the lower plate 6b, and the two side plates 6c by welding or the like at the position of the node 21a of the standing wave 21 that is separated from the predicted partition wall 12 by the installation distance L.

  As a result, the closed space portion 18 is divided into two regions, a first closed space portion 18b and a second closed space portion 18c. As shown in FIG. 5, the waveform of the standing wave 21 that is generated when the hydraulic excavator is driven. Is deformed. Thereby, the specific resonant frequency which the closed space part 18 in the intermediate part 15 has can be changed, and resonance inside the boom 6 can be suppressed.

  In the present embodiment configured as described above, the partition plate 20 for noise reduction that partitions the inside of the closed space portion 18 of the intermediate portion 15 of the boom 6 is provided in the standing wave node 21a. Thus, the area in the closed space portion 18 can be changed into two areas of the closed space portion 18b and the closed space portion 18c. Thus, as described above, the resonance frequency that generates the standing wave 21 can be changed, so that the intermediate portion can be obtained without filling the boom 6 as the front structure 5 with a damping material, a sound absorbing material, or the like. 15 can be suppressed. Since the partition plate 20 can be attached relatively easily by welding or the like in the process of manufacturing the boom 6, after the boom 6 is formed as a hollow structure, the damping material and the sound absorbing material are attached to the boom. No complicated work is required to fill the middle part 15 of the six, and the number of work steps required to manufacture the boom 6 can be reduced.

  In this embodiment, the partition plate 20 is provided at the node 21a of the standing wave 21 generated in the closed space portion 18 of the intermediate portion 15 described above. However, as described above, the partition plate 20 of the standing wave 21 shown in FIG. Even if it is provided on the belly 21b, noise generated in the intermediate portion 15 of the boom 6 can be reduced.

  Also, when the partition plate 20 is provided for the closed space portions 17 and 19, it can be provided in the same manner as described above.

  In the above description, the partition plate 20 is provided in the closed space portion 18 of the intermediate portion 15 described above. In particular, this closed plate 20 passes through the side or the vicinity of the cab 3 when the boom 6 rotates. By providing in the part 17, the noise of this part can be reduced, the noise which propagates to a driver's cab can be reduced, and the noise with respect to an operator can be reduced.

  Further, although the partition plate 20 is provided separately from the partition wall 12 of the boom 6, the partition plate 12 may be configured to also serve as the partition plate 20. When configured in this way, noise can be reduced as in the above-described embodiment, and the number of partition plates can be reduced. As a result, the manufacturing cost can be reduced and the number of work steps required for manufacturing the boom 6 can be reduced.

  Further, by making the partition plate 20, the upper plate 6a, the lower plate 6b, the two side plates 6c of the boom 6 and the partition wall 12 the same material, it is possible to reduce labor for manufacturing and recycling the boom 6. Can do.

  Moreover, although the partition plate 20 is provided so as to be orthogonal to the longitudinal direction of the boom 6, noise generated in the boom 6 can be reduced even if the partition plate 20 is provided along the longitudinal direction of the boom 6. Can do.

  Further, the partition plate 20 is made of a steel plate made of the same material as the upper plate 6a, the lower plate 6b, the two side plates 6c, and the partition wall 12 of the boom 6, and the partition plate 20 is made of, for example, wood. The noise generated from the boom 6 can be reduced as a member made of another material.

  In this embodiment, the boom 6 is provided with the partition plate 20 for noise reduction, but may be applied to the arm 7. In such a case, noise generated from the arm 7 can be reduced.

1 is a side view of a hydraulic excavator cited as an example of a construction machine including an embodiment of a construction machine working device according to the present invention. It is a side view of the boom which comprises the working device which concerns on this embodiment with which the hydraulic shovel shown in FIG. 1 is equipped. It is principal part sectional drawing seen from A arrow of FIG. It is a figure which shows an example of installation of the partition plate for noise reduction with which this embodiment is equipped. It is a figure which shows the changed standing wave obtained in this embodiment.

Explanation of symbols

3 cab 5 front structure 6 boom 6a upper plate 6b lower plate 6c side plate 7 arm 12 partition 13 foot pin 14 foot pin side portion 15 intermediate portion 16 front end side portion 17 closed space portion 18 closed space portion 18b first closed space portion 18c first 2 Blocking space portion 19 Blocking space portion 20 Partition plate 21 Standing wave 21a Node 21b Abdomen

Claims (6)

In a construction machine working apparatus comprising a front structure having a hollow structure and a front structure having a partition wall which is provided in a body of the construction machine so as to be pivotable in the vertical direction and increases the strength thereof.
A noise reduction partition plate for partitioning the closed space portion is provided at a predetermined position in the closed space portion formed by the partition wall based on a standing wave generated when the construction machine is driven. Construction equipment working equipment. In the invention of claim 1,
The front structure includes a box-shaped hollow structure including an upper plate, a lower plate, and left and right side plates, and the partition is provided so as to divide an internal space of the hollow structure into a plurality of closed spaces. A working device for construction machinery. In the invention according to claim 1 or 2,
The working device for a construction machine, wherein the partition plate is provided orthogonal to a longitudinal direction of the front structure. In the invention according to any one of claims 1 to 3,
The vehicle body is provided with a cab, and the front structure is provided so as to rotate in the vicinity of a side surface of the cab,
The work apparatus for a construction machine, wherein the partition plate is provided in the closed space that passes through a side of the cab and the vicinity of the side when the front structure rotates. In the invention of claim 1,
The working device for a construction machine, wherein the partition wall also serves as the partition plate. In the invention according to any one of claims 1 to 5,
A working device for a construction machine, characterized in that the partition plate is arranged at a position corresponding to a node of a standing wave generated in the hollow structure body or an antinode.

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