JP5781295B2 - Construction machinery - Google Patents

Description

  The present invention relates to a construction machine such as a crane, and more particularly to a structure for reducing vibration of a cab (cab) of a construction machine and noise in the cab.

  With regard to this type of technology, for example, there are those described in Patent Documents 1 to 3. Patent Document 1 describes a construction machine in which a sound insulating material is attached to the entire bottom surface of a cab floor plate and a porous under cover is attached to the bottom surface of a vehicle body frame. In the construction machine described in Patent Document 2, the space below the cab is used as a passage for introducing cooling air into the engine room, and a sound absorbing material is attached to the inner surface of the passage, or a branch is attached to the passage. The noise from the engine compartment is reduced by installing side branch type resonance. Moreover, in patent document 3, the sound insulation chamber which attached the sound insulation material is provided in the circumference | surroundings of a cab, and it prevents that a noise penetrate | invades directly into a cab.

Japanese Utility Model Publication 3-55654 JP 2008-155790 A JP 2000-355955 A

  The techniques described in Patent Documents 1 to 3 have the following problems, respectively. In the technique described in Patent Document 1, the propagation of noise from under the cab into the cab is suppressed by a sound insulating material attached to the entire lower surface of the cab floor board. On the other hand, there are cases where openings such as operation pipes for construction machines and openings for air conditioning are provided in the cab floor board. In this case, even if a sound insulating material is attached to the lower surface of the cab floor plate, noise enters from the opening into the cab. In addition, the sound insulating material described in Patent Document 1 has a frequency band in which the sound insulating effect is reduced due to the coincidence effect. When the frequency of the excitation force overlaps with the frequency band, the noise in the cab may not be reduced. There is.

  Further, the sound absorbing material described in Patent Document 2 has a small sound absorbing effect with respect to noise in a low frequency band. The side-branch type resonator basically has a small silencing effect other than the sound of the target frequency. When it is necessary to reduce the sound of a plurality of frequencies, a plurality of resonance rods must be provided. In this case, it is difficult to secure a place for installing the resonance rods. Further, the technique described in Patent Document 2 cannot reduce the vibration of the cab due to the vibration propagating from the engine room or the like.

  In the sound insulation chamber provided around the cab as described in Patent Document 3, when the high-pressure hydraulic piping is extended from the rear of the cab to the bottom of the cab, and the piping passes through the interior of the sound insulation chamber, the hydraulic piping is supported. It is necessary to provide the part in the sound insulation chamber. In Patent Document 3, since no special vibration reduction measures are taken for the sound insulation chamber and the cab itself, the vibration transmitted through the hydraulic pipe is transmitted from the pipe support to the member under the cab floor, and the member under the cab floor is vibrated. Vibration and noise will be generated. Further, when cooling the engine room by introducing cooling air from behind the cab or the lower side of the cab, the passage area of the cooling air is reduced by providing the sound insulation chamber, so there is a possibility that the air volume of the cooling air is insufficient.

  The present invention has been made in view of the above circumstances, and an object thereof is to reduce both vibration and noise propagating from under the cab into the cab in a construction machine in which an engine room is arranged behind the cab. It is to provide a cab structure that can.

  The present invention relates to a construction machine in which an upper swing body is mounted on a lower traveling body, and the upper swing body includes a cab provided at a front portion, an engine chamber provided behind the cab, A deck having a space in which the cab and the engine room are mounted, and a square member having a C-shaped or quadrangular cross section is fixed to the lower surface of the floor plate of the cab, and the deck has an internal space. The construction machine is characterized in that the square members are arranged in the left-right direction.

  According to this configuration, the square member having a C-shaped or quadrangular cross section is fixed to the lower surface of the floor plate of the cab, thereby increasing the rigidity of the floor plate of the cab, and as a result, the floor plate is less likely to vibrate. Further, the vertical space between the square member fixed to the lower surface of the cab floor plate and the bottom plate of the deck is narrower than the vertical space between the cab floor plate and the deck bottom plate. That is, the volume inside the deck changes between where the square member is present and where the square member is not present, and a sound reduction effect can be obtained by forming the expansion silencer structure inside the deck.

  That is, by fixing a square member having a C-shaped or quadrangular cross section to the lower surface of the cab floor plate, the rigidity of the cab floor plate can be improved and an expansion type sound reduction effect can be obtained. Both noises can be reduced. As a result, the vibration of the cab and the noise in the cab are reduced. In addition, the noise radiated from under the cab to the surroundings of the construction machine can be reduced by providing an expansion type sound reduction effect inside the deck.

  Further, in the present invention, a plurality of the square members are fixed to the lower surface of the floor board at intervals in the front-rear direction of the deck, and the intervals between the adjacent square members are all different, It is preferable that the interval ratio not be a multiple ratio.

  In the expansion type sound reduction, the frequency to be reduced is determined by the length of the expansion portion. According to this configuration, it is possible to reduce sounds having a plurality of frequencies. In other words, the frequency band where the sound reduction effect is reduced can be reduced, and as a result, noise is further reduced.

  Further, in the present invention, the square member is a C-shaped member having a C-shaped cross section, and is spaced in the front-rear direction of the deck in a state where the opening is directed to the front direction or the rear direction of the deck. The plurality of C-shaped members are fixed to the lower surface of the floor plate, and extend from the back plate portion of one of the C-shaped members to the inside of the opening of the other adjacent C-shaped member in the front-rear direction of the deck. It is preferable that the plate member is extended along, and the said plate member is arrange | positioned below the up-down direction intermediate position of the back plate part of the said C-shaped member.

  According to this configuration, the plate member described above serves as a sound insulating plate, and noise that has entered the cab (inside the deck) can be prevented from entering the cab directly from under the cab floor. Moreover, the noise transmitted into the cab can be more effectively reduced by disposing the plate member below the intermediate position in the vertical direction of the back plate portion of the C-shaped member.

  Further, in the present invention, the square member is a C-shaped member having a C-shaped cross section, and a saddle plate is provided at an end of a portion forming the opening of the C-shaped member, and the opening is directed upward. In this state, it is preferable that the C-shaped member is fixed to the lower surface of the floor board via a gutter.

  According to this configuration, the rigidity of the cab floor can be further increased, and as a result, the vibration of the cab is further reduced.

  Further, in the present invention, a second square member having a C-shaped or quadrangular cross section is provided below the square member and on the upper surface of the bottom plate of the deck, so that the longitudinal direction of the deck is aligned with the position of the square member. It is preferable that the second square member is disposed in the internal space of the deck together with the square member.

  According to this configuration, the rigidity of the bottom plate of the deck is increased by the second rectangular member, the bottom plate is less likely to vibrate, the volume change inside the deck is increased, and the expansion type sound reduction effect is improved. As a result, noise transmitted into the cab and noise radiated from under the cab to the surroundings of the construction machine are further reduced.

  Further, in the present invention, the second rectangular member is a second C-shaped member having a C-shaped cross section, and a plurality of the second C-shaped members in a state where the opening is directed in the front direction or the rear direction of the deck. Is fixed to the upper surface of the bottom plate of the deck, and from the back plate portion of one of the second C-shaped members to the inside of the opening of the other adjacent second C-shaped member along the front-rear direction of the deck. Preferably, the two plate members are extended, and the second plate member is disposed above the intermediate position in the vertical direction of the back plate portion of the second C-shaped member.

  According to this configuration, the second plate member serves as a sound insulating plate, and noise that has entered the cab (inside the deck) can be prevented from leaking outside the deck. Moreover, the noise which leaks outside a deck can be more effectively reduced by arrange | positioning a 2nd board member above the up-down direction intermediate position of the backplate part of a 2C-shaped member. As a result, noise radiated from under the cab around the construction machine is further reduced.

  Further, in the present invention, the second rectangular member is a second C-shaped member having a C-shaped cross section, and a saddle plate is provided at an end of a portion forming the opening of the second C-shaped member, and the downward direction It is preferable that the second C-shaped member is fixed to the upper surface of the bottom plate of the deck through a gutter plate with the opening directed to the top.

  According to this configuration, the rigidity of the bottom plate of the deck is further increased by the second C-shaped member, and the bottom plate is more difficult to vibrate.

  According to the present invention, both the vibration and noise propagating from under the cab into the cab are reduced by fixing the constituent elements of the present invention, in particular, a square member having a C-shaped or quadrangular cross section to the lower surface of the cab floor. can do. As a result, the vibration of the cab and the noise in the cab are reduced.

It is a figure which shows the structure under the cab of the construction machine which concerns on 1st Embodiment of this invention. It is a figure which shows the structure under the cab of the construction machine which concerns on 2nd Embodiment of this invention. It is a figure which shows the structure under the cab of the construction machine which concerns on 3rd Embodiment of this invention. It is a figure which shows the structure under the cab of the construction machine which concerns on 4th Embodiment of this invention. It is a figure which shows the structure under the cab of the construction machine which concerns on 5th Embodiment of this invention. It is a figure which shows the structure under the cab of the construction machine which concerns on 6th Embodiment of this invention. It is a graph which shows the result of having compared the vibration level of a cab floor board with the case where there is a C-shaped member and the case where it does not exist. It is a graph which shows the result of having compared the noise level transmitted from the under floor space of a cab to a cab floor board. It is a graph which shows the result of having compared the noise level transmitted to the cab floor board from the under floor space of a cab at the time of changing the position of the board member fixed to the backplate part of a C-shaped member.

  Hereinafter, embodiments for carrying out the present invention will be described with reference to the drawings. The structure under the cab according to the present invention can be applied to various construction machines including cranes.

(First embodiment)
The structure under the cab of the construction machine according to the first embodiment of the present invention will be described with reference to FIG. FIG. 1 shows a part of the upper swing body 1 mounted on the lower traveling body of the construction machine. The lower traveling body is for traveling a construction machine, and there are traveling bodies such as a crawler type and a wheel type. Fig.1 (a) is a side view, FIG.1 (b) is AA sectional drawing of Fig.1 (a).

  Here, the upper swing body 1 includes a cab 2 that is provided at a front portion thereof and accommodates a seat 7, and an engine room 3 that is provided at the rear of the cab 2. A deck 4 that houses the operation system rod 11, the hydraulic piping 21, the valve 22 (for hydraulic piping) and the like is provided. Although illustration is omitted, for example, a boom is attached to the upper swing body 1 so as to be raised and lowered.

  The operation system rod 11 is passed from the engine chamber 3 into the cab 2 through the deck 4. A piping cover 11 a is attached to the floor plate 2 a of the cab 2. For example, the operation system rod 11 is raised from the inside of the deck 4 into the cab 2 from this portion. Here, hydraulic vibration is transmitted to the floor plate 2 a from the valve 22 and the support portion of the hydraulic pipe 21 accommodated in the deck 4. Further, the vibration of the engine 10 in the engine room 3 is transmitted to the floor board 2a, and the floor board 2a vibrates.

  The floor 2a of the cab 2 is provided with an opening 2b. The opening 2b is for passing a cable or the like, for example. The noise of the engine 10, the noise of the hydraulic piping, etc. enter the cab 2 from the opening 2b.

  An engine chamber 3 provided behind the cab 2 accommodates an engine 10 and a radiator 9. Air for cooling the engine 10 is introduced from an intake port 8 provided on the back side surface of the cab 2. In addition, a hole (opening) such as a slit may be provided in the front plate 4c of the deck 4 to be described later, and air for cooling the engine 10 may be introduced from the front plate 4c into the engine chamber 3 through the deck 4.

  The deck 4 includes a bottom plate 4b, a side plate 4a, a front plate 4c, and a back plate (not shown). The deck 4 and the cab 2 are partitioned by the floor plate 2 a of the cab 2. The front plate 4c is inclined with respect to the vertical direction, but is not limited thereto.

(C-shaped member)
Here, a plurality of metal C-shaped members 5 are fixed to the lower surface of the floor plate 2 a of the cab 2, and the C-shaped members 5 are arranged in the internal space of the deck 4. The C-shaped member 5 is a long member, and is a U-shaped member including a back plate portion 5c and side plate portions 5a and 5b on both sides of the back plate portion 5c. Examples of the material of the C-shaped member 5 include carbon steel and stainless steel. Three plate members may be joined together by welding or the like to form the C-shaped member 5, or a channel (grooved steel) may be used as the C-shaped member 5. (The same applies to the second C-shaped member 6 described later)

  The C-shaped member 5 is fixed to the lower surface of the floor plate 2 a so that its longitudinal direction is parallel to the width direction of the deck 4. Both ends in the longitudinal direction of the C-shaped members 5 in the second and third rows counted from the front side of the deck 4 are fixed in contact with the side plates 4 a of the deck 4. The length of the C-shaped member 5 in the first row is shorter than the length of the C-shaped members 5 in the second and third rows in order to avoid the position of the piping cover 11a. The openings S of the C-shaped member 5 are all directed in the front direction of the deck 4. Note that the opening S of the C-shaped member 5 may be directed to the rear side of the deck 4.

  In the present embodiment, three C-shaped members 5 are fixed to the lower surface of the floor plate 2 a of the cab 2 with an interval in the front-rear direction of the deck 4. When the interval between adjacent C-shaped members 5 is L1 and L2 in order from the front side of the deck 4, L1 = L2.

(2C type member)
A plurality of second C-shaped members 6 made of metal are fixed to the upper surface of the bottom plate 4 b of the deck 4 at a portion below the cab 2, and a plurality of second C-shaped members 6 together with the plurality of C-shaped members 5 are fixed. Are arranged in the internal space of the deck 4. The second C-shaped member 6 is a long member, and is a U-shaped member including a back plate portion 6c and side plate portions 6a and 6b on both sides of the back plate portion 6c. Examples of the material of the second C-shaped member 6 include carbon steel and stainless steel.

  The second C-shaped member 6 is fixed to the upper surface of the bottom plate 4 b so that its longitudinal direction is parallel to the width direction of the deck 4. Both ends in the longitudinal direction of the second C-shaped member 6 are in contact with and fixed to the side plates 4 a of the deck 4. In addition, regarding the position of the deck 4 in the front-rear direction, the second C-shaped member 6 is arranged in accordance with the position of the upper C-shaped member 5. The opening S of the second C-shaped member 6 is directed in the front direction of the deck 4. Note that the opening S of the second C-shaped member 6 may be directed to the rear side of the deck 4. In the present embodiment, three second C-shaped members 6 are fixed to the upper surface of the bottom plate 4 b of the deck 4 with an interval in the front-rear direction of the deck 4.

  Further, the C-shaped member 5 and the second C-shaped member 6 arranged above and below are members having the same shape and dimensions except for the C-shaped member 5 in the first row. In addition, the dimension of the C-shaped member 5 and the dimension of the 2nd C-shaped member 6 which are paired up and down may differ. For example, the C-shaped member 5 may be larger than the second C-shaped member 6. Further, the cross-sectional shapes of the C-shaped member 5 and the second C-shaped member 6 are both C-shaped, but at least one of these members may have a rectangular cross-sectional shape. Further, the second C-shaped member 6 is not necessarily a necessary member, and only the C-shaped member 5 may be provided. Furthermore, there may be only one C-shaped member 5.

(Action / Effect)
According to the present invention, since the C-shaped member 5 is fixed to the lower surface of the floor plate 2a of the cab 2, the rigidity of the floor plate 2a of the cab 2 is increased, and as a result, the floor plate 2a is less likely to vibrate. Further, the vertical space between the C-shaped member 5 and the second C-shaped member 6 inside the deck 4 is narrower than the vertical space between the floor plate 2 a of the cab and the bottom plate 4 b of the deck 4. That is, the volume inside the deck 4 changes depending on where the C-shaped member 5 and the second C-shaped member 6 are present, and an expansion type sound reduction effect is obtained inside the deck 4.

  Thus, by fixing the C-shaped member 5 to the lower surface of the floor plate 2a of the cab 2, the rigidity of the cab floor plate 2a can be improved and an expansion-type noise reduction effect can be obtained, and the hydraulic piping 21, the valve 22, the engine 10, etc. It is possible to suppress the vibration from being transmitted to the floor plate 2a and to suppress the vibration of the floor plate 2a, and it is possible to reduce noise from under the cab of the hydraulic pipe 21, the valve 22, the engine 10, and the like by the expansion type sound reduction effect. As a result, the vibration of the cab 2 and the noise in the cab 2 are reduced.

  Note that the vertical distance between the C-shaped member 5 and the second C-shaped member 6 (the vertical distance between the C-shaped member 5 and the bottom plate 4b when the second C-shaped member 6 is not provided). The ratio of the vertical spacing between the floor plate 2a and the bottom plate 4b (expansion ratio) is preferably 2.5 or more.

  Further, the second C-shaped member 6 increases the rigidity of the bottom plate 4b of the deck 4, and the bottom plate 4b is less likely to vibrate. In addition, the C-shaped member 5 and the second C-shaped member 6 provide an expansion-type sound reduction effect inside the deck, so that noise radiated from under the cab around the construction machine is also reduced.

(Second Embodiment)
Next, the structure under the cab according to the second embodiment will be described with reference to FIG. FIG. 2 is a side view showing a part of the upper swing body 102 according to the second embodiment. Differences from the first embodiment will be described below.

  A plurality of C-shaped members 5 and second C-shaped members 6 are fixed to the lower surface of the floor plate 2a of the cab 2 and the upper surface of the bottom plate 4b of the deck 4 with a space in the front-rear direction of the deck 4, respectively. Common to the first embodiment and the second embodiment. In the second embodiment, assuming that the distance between adjacent C-shaped members 5 and the distance between adjacent second C-shaped members 6 are L1 and L2 in order from the front side of the deck 4, L1> L2 and L1 The ratio between L2 and L2 is not set to be a multiple ratio. In addition, it is good also as L1 <L2 by the ratio which does not become a multiple ratio.

  Here, in the expansion type sound reduction, the frequency to be reduced is determined by the length (L1, L2) of the expansion portion. According to the present embodiment, it is possible to reduce sound having a plurality of frequencies. In other words, the frequency band in which the sound reduction effect is reduced can be reduced, and as a result, noise can be further reduced. It should be noted that the sound reduction effect can be further improved by setting L1 and L2 to be ¼ wavelength lengths of noise from the engine 10, hydraulic pump, hydraulic piping, and the like, which are noise reduction targets.

(Third embodiment)
Next, the structure under the cab according to the third embodiment will be described with reference to FIG. FIG. 3 is a side view showing a part of the upper swing body 103 according to the third embodiment. Differences from the first embodiment will be described below.

  In this embodiment, the plate members (12, 13) are disposed between adjacent C-shaped members. Specifically, the plate member 12 extends from the back plate portion 5c of the C-shaped member 5 in the first row to the inside of the opening of the C-shaped member 5 in the adjacent second row. The plate member 12 is parallel to the floor plate 2a of the cab 2 in the horizontal direction, and is disposed below the intermediate position in the vertical direction of the back plate portion 5c of the C-shaped member 5 in the vertical direction. Yes. The same applies to the plate member 12 between the C-shaped member 5 in the second row and the C-shaped member 5 in the third row.

  Similarly, the second plate member 13 extends from the back plate portion 6c of the second C-shaped member 6 in the first row to the inside of the opening of the second C-shaped member 6 in the adjacent second row. The second plate member 13 is parallel to the bottom plate 4b of the deck 4 in the horizontal direction, and is arranged above the intermediate position in the vertical direction of the back plate portion 6c of the second C-shaped member 6 in the vertical direction. Has been. The same applies to the second plate member 13 between the second C-shaped member 6 in the second row and the second C-shaped member 6 in the third row.

  According to the present embodiment, the plate member 12 serves as a sound insulating plate, and noise that has entered the cab (inside the deck 4) from the engine room 3 or the like can be prevented from entering the cab directly from the bottom of the cab 2. . Further, by disposing the plate member 12 below the intermediate position in the vertical direction of the back plate portion 5c of the C-shaped member 5, noise transmitted to the cab can be more effectively reduced.

  Similarly to the plate member 12, the second plate member 13 also serves as a sound insulating plate, and this second plate member 13 prevents noise that has entered under the cab (inside the deck 4) from leaking outside the deck. By disposing the second plate member 13 above the intermediate position in the vertical direction of the back plate portion 6c of the second C-shaped member 6, noise leaking outside the deck can be more effectively reduced.

  In addition, the plate member 12 is attached to the back plate portion 5c of one C-shaped member 5 and the plate member 12 is not in contact with the other adjacent C-shaped member 5 because of vibration between adjacent C-shaped members 5. This is to avoid transmission (the same applies to the second plate member 13).

(Fourth embodiment)
Next, the structure under the cab according to the fourth embodiment will be described with reference to FIG. FIG. 4 is a side view showing a part of the upper swing body 104 according to the fourth embodiment. Differences from the first embodiment will be described below.

  In the present embodiment, the hat-shaped member is a member that is fixed to the lower surface of the floor plate 2a of the cab 2 by attaching the roof plate 14 to the end of the portion of the C-shaped member 5 where the opening S is formed. Specifically, a hat plate 14 is attached to the ends of the side plate portions 5a and 5b constituting the C-shaped member 5 on the opening S side, and the C-shaped member 5 and the two rib plates 14 as a whole are hat-shaped members. It is said. And this hat-shaped member is being fixed to the lower surface of the floor board 2a via the girder board 14 with the opening S facing upward.

  The same applies to the second C-shaped member 6, and a saddle plate is attached to the end of the portion forming the opening of the second C-shaped member 6, and the opening S is directed downward on the upper surface of the bottom plate 4 b of the deck 4. The 2C-shaped member 6 is fixed via a saddle plate.

  According to this embodiment, compared to the arrangement of the C-shaped member 5 (second C-shaped member 6) in the first embodiment (the opening S faces the front-rear direction of the deck 4), the floor board 2a of the cab 2 (deck 4). The rigidity of the bottom plate 4b) can be further increased, and the vibration of the cab 2 (deck 4) can be further reduced. An expansion type sound reduction effect can be obtained at the same time.

(Fifth embodiment)
Next, the structure under the cab according to the fifth embodiment will be described with reference to FIG. FIG. 5 is a side view showing a part of the upper swing body 105 according to the fifth embodiment. Differences from the first embodiment will be described below.

  In the present embodiment, the reinforcing plate 15 is attached to the end on the opening side of one side plate portion 5b constituting the C-shaped member 5. Then, the C-shaped member 5 is fixed to the lower surface of the floor plate 2a with the opening of the C-shaped member 5 facing downward, and the other side plate portion 5a constituting the C-shaped member 5 and the adjacent C-shaped member 5 A cushioning material 16 is interposed therebetween. The side plate portion 5b and the reinforcing plate 15 may be integrally formed. That is, the reinforcing plate 15 (bending portion) may be provided by bending the plate material. The buffer material 16 is, for example, a urethane rubber mat. As shown in FIG. 5, the second C-shaped member 6 is similarly reinforced and provided with a cushioning material 16.

  According to the present embodiment, by attaching the reinforcing plate 15 to the side plate portion 5b of the C-shaped member 5 (or by providing a bent portion at the end of the side plate portion 5b of the C-shaped member 5), the C-shaped member 5 As a result, the rigidity of the floor 2a of the cab 2 can be further increased, and the vibration of the cab 2 can be further reduced. Further, when the length of the C-shaped member 5 in the front-rear direction of the deck 4 is increased in order to increase the rigidity of the floor plate 2 a, the cushioning material 16 is inserted between the adjacent C-shaped members 5, thereby the C-shaped member 5. The vibration transmission between the cab 2 and the cab 2 can be further reduced.

  A reinforcing plate is attached to one side plate portion of the second C-shaped member 6, and a cushioning material is inserted between the other side plate portion of the second C-shaped member 6 and the adjacent second C-shaped member 6. The effect of is also the same as described above.

(Sixth embodiment)
Next, the structure under the cab according to the sixth embodiment will be described with reference to FIG. FIG. 6 is a side view showing a part of the upper swing body 106 according to the sixth embodiment. Differences from the fifth embodiment will be described below.

  In the present embodiment, a further reinforcing plate 17 is attached from the end of the reinforcing plate 15 toward the back plate portion 5c. The reinforcing plate 17 and the back plate portion 5 c are fixed via a flange plate 18 provided at the end of the reinforcing plate 17. Note that the side plate portion 5b, the reinforcing plate 15, the reinforcing plate 17, and the flange plate 18 may be integrally formed. That is, the reinforcing plate 15 part, the reinforcing plate 17 part, and the flange plate 18 part may be provided by bending the plate material. As shown in FIG. 6, the same reinforcement is made for the second C-shaped member 6.

  According to the present embodiment, the rigidity of the floor plate 2a of the cab 2 and the bottom plate 4b of the deck 4 can be further increased.

(Effectiveness verification results)
FIG. 7 is a graph showing a result of comparing the vibration level of the floor board 2a by numerical analysis when the C-shaped member 5 is provided on the lower surface of the floor board 2a of the cab 2 and when it is not provided. As can be seen from FIG. 7, when the C-shaped member 5 is provided on the lower surface of the floor plate 2 a of the cab 2, the vibration level of the floor plate 2 a is generally smaller than when the C-shaped member 5 is not provided. Moreover, most of the peak values of the vibration level are small.

  FIG. 8 is a graph showing the result of a numerical analysis comparing the noise level transmitted from the space under the cab 2 (inside the deck 4) to the cab floor plate 2a. Case 1 is a case where no C-shaped member is provided. Case 2 is a case where the three C-shaped members 5 and the second C-shaped members 6 are provided at equal intervals. Case 3 is a case where the three C-shaped members 5 and the second C-shaped members 6 are provided at unequal intervals. As can be seen from FIG. 8, in Case 2 and Case 3, the noise level is reduced by about 8 dB compared to Case 1. In Case 2 and Case 3, the noise level reduction amount is larger in Case 3.

  FIG. 9 shows the noise level transmitted from the space under the cab 2 (inside the deck 4) to the cab floor plate 2a when the position of the plate member 12 fixed to the back plate portion 5c of the C-shaped member 5 is changed in the vertical direction. It is a graph which shows the result compared by numerical analysis. As can be seen from FIG. 9, the noise level is reduced by about 10 dB when the plate member 12 is disposed below the intermediate position in the vertical direction of the back plate portion 5 c of the C-shaped member 5.

  Although the embodiments of the present invention have been described above, the present invention is not limited to the above-described embodiments, and various modifications can be made as long as they are described in the claims. .

1: Upper swing body 2: Cab 2a: Floor board 3: Engine room 4: Deck 5: C-shaped member 6: Second C-shaped member 7: Seat 8: Inlet 9: Radiator 10: Engine 11: Operating rod 11a: Piping Cover 21: Hydraulic piping 22: Valve 2b: Opening

Claims (7)

In a construction machine in which an upper turning body is mounted on a lower traveling body,
The upper swing body has a cab provided at the front, an engine room provided at the rear of the cab, and a deck having a space in which the cab and the engine room are mounted.
A square member having a C-shaped or quadrangular cross section is fixed to the lower surface of the floor plate of the cab, and the square member is arranged in the left-right direction in the internal space of the deck,
The space below the square member in the internal space communicates with the space located in front of and behind the space in the front-rear direction of the deck, and
The construction machine according to claim 1, wherein a height of the space below the square member in the internal space is lower than a maximum height of a space located in front of and behind the space in the front-rear direction of the deck . The construction machine according to claim 1,
A plurality of the square members are fixed to the lower surface of the floor board at intervals in the front-rear direction of the deck,
The construction machine is characterized in that the intervals between the adjacent square members are all different intervals, and the ratio of the intervals is not a multiple ratio. The construction machine according to claim 1 ,
The square member is a C-shaped member having a C-shaped cross section,
A plurality of the C-shaped members are fixed to the lower surface of the floor board with an interval in the front-rear direction of the deck with the opening directed in the front direction or the rear direction of the deck,
A plate member extends along the front-rear direction of the deck from the back plate portion of one of the C-shaped members to the inside of the opening of the other adjacent C-shaped member,
A construction machine, wherein the plate member is disposed below an intermediate position in a vertical direction of a back plate portion of the C-shaped member. The construction machine according to claim 1 or 2,
The square member is a C-shaped member having a C-shaped cross section,
A saddle plate is provided at the end of the portion forming the opening of the C-shaped member,
A construction machine, wherein the C-shaped member is fixed to a lower surface of the floor board through a gutter with an opening directed upward. In the construction machine in any one of Claims 1-4,
A second square member having a C-shaped or quadrangular cross section is fixed below the square member on the top surface of the bottom plate of the deck according to the position of the square member in the front-rear direction of the deck, and The construction machine, wherein the second square member is arranged in the internal space of the deck together with the square member. The construction machine according to claim 5,
The second square member is a second C-shaped member having a C-shaped cross section,
A plurality of the second C-shaped members are fixed to the upper surface of the bottom plate of the deck, with the opening directed in the front direction or the rear direction of the deck,
The second plate member extends along the front-rear direction of the deck from the back plate portion of one of the second C-shaped members to the inside of the opening of the other adjacent second C-shaped member,
The construction machine, wherein the second plate member is disposed above an intermediate position in the vertical direction of the back plate portion of the second C-shaped member. The construction machine according to claim 5,
The second square member is a second C-shaped member having a C-shaped cross section,
A saddle plate is provided at the end of the portion forming the opening of the second C-shaped member,
The construction machine, wherein the second C-shaped member is fixed to the upper surface of the bottom plate of the deck through a gutter plate with the opening directed downward.

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