JPH07174191A - Vibration isolation supporting device for operator's cab in construction machine - Google Patents

Abstract

PURPOSE:To provide a vibration isolation device in a plurality of portions in a horizontal structural member of closed sectional structure, so that the device can be mounted with its height position to make flatness accurately to each other, and further to improve rigidity and strength of the horizontal structural member on which this vibration isolating device is mounted. CONSTITUTION:A mounting bracket 30, welded to horizontal structural members 3b, 3c of closed sectional structure, is formed of a mounting part 30a of mounting a vibration isolating device 10, securing part 30b of welding peripheral locations to the members 3b, 3c and reinforcing part 30c. A through hole is left as drilled in the mounting part 30a, a bolt inserting hole is provided in four parts in the periphery of this through hole, a bolt is inserted from downward, further in the vibration isolating device 10, its cylindrical main unit is inserted into the through hole, the bolt inserting holes are made to agree with each other in a condition that a mounting plate 18 is brought into contact with a surface of the mounting part 30a, the bolts are protruded from downward toward upward, and nuts 20 are screwed.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a driver's cab anti-vibration support device for supporting a driver's cab of a construction machine such as a hydraulic excavator via a vibration isolator.

[0002]

2. Description of the Related Art In construction machines such as hydraulic excavators, an upper revolving structure is rotatably provided on a lower traveling structure provided with crawler tracks for traveling, and the upper revolving structure comprises a boom, an arm and a bucket. A front working mechanism is provided. In addition to the front working mechanism described above, the upper revolving structure is provided with a driver's cab, and in addition to this, machines such as an engine and a hydraulic pump are provided, and members such as a counterweight are mounted. ing.

FIG. 4 shows the structure of the upper swing body. In the same figure, as the structure 1 of the upper swing body, a plurality of main structural members 2 extending in the front-rear direction of the vehicle and a plurality of appropriate main body members 2 are stretched over at appropriate positions. And the lateral structural member 3 thus provided. Two brackets 4 and 4 are fixedly provided on the two main structural members 2 at the substantially central position, and the base end portions of the booms constituting the front working mechanism are attached to the brackets 4 and 4. Be connected. The driver's cab 5 is installed at a portion between the main structural member (indicated by reference numeral 2a in the drawing) to which the bracket 4 is attached and the main structural member on the end side (indicated by reference numeral 2b in the drawing). There is.

Although the vehicle vibrates violently during running and working, the driver's cab 5 is mounted on the structure 1 via a vibration-proof support mechanism in order to prevent this vibration from being transmitted to the driver's cab 5 as much as possible. ing. That is, as shown in FIG. 5, the structure 1 has six (or four) vibration-damping devices 1.
0 is provided, and the driver's cab 5 is supported on the structure 1 by this vibration isolation device 10. Here, the vibration isolation device 10
As for the mounting position of (1), since it is necessary to first provide a through hole for mounting this vibration isolator 10, it cannot be installed on the side of the main structural members 2a, 2b that must maintain extremely high strength. In addition, it is provided on the lateral structural member 3 side.

Here, when the vehicle is traveling or when excavating earth and sand and other work, a considerably large load is applied to the lateral structural member 3. Moreover, although the lateral structural member 3 is supported by the driver's cab 5 though the vibration isolator 10 is interposed, the lateral structural member 3 is subjected to a twisting force or a bending force, which results in the driving. Low-frequency vibrations are transmitted to the room 5, which makes the ride quality uncomfortable for the operator. For this reason, the lateral structure member 3 is required to have high rigidity, and therefore, of the three lateral structure members 3 provided at the site where the cab 5 is mounted, the lateral structure member 3a at the most distal end is provided.
Regardless, the other lateral structural members 3b and 3c have a closed cross-sectional structure to improve the rigidity.

FIG. 6 shows a cross section of the vibration isolator 10 mounted on the lateral structural members 3b (and 3c). The vibration isolation device 10 has a cylindrical main body 11 formed in a cylindrical shape.
A bottom plate 12 is connected to the lower part of the above, and an elastic member 13 such as rubber is adhered to the upper part thereof to form a sealed damping force generating chamber 14 inside. And this damping force generation chamber 1
A working fluid having a high viscosity, such as silicon oil, is enclosed in the inside 4. The elastic member 13 includes a connecting member 1
5 is fixedly provided, and the lower end of the connecting member 15 faces the inside of the damping force generation chamber 14 and is connected to the movable plate 16. A receiving plate 17 is connected to a portion of the connecting member 15 that protrudes outward from the elastic member 13, and a tip end side of the receiving plate 17 is a screw portion. Further, a mounting plate 18 having a substantially square outer shape is fixedly provided near the upper end of the cylindrical main body 11. Bolt insertion holes 18 a for inserting the bolts 19 are formed at four corners of the mounting plate 18.

The vibration isolator 10 has the above structure, and the lateral structure member 3 to which the vibration isolator 10 is fixed is fixed.
b and 3c are body portions 3b whose cross section is bent in an inverted U shape.
A flat bottom plate 3bB, 3cB is welded and fixed to M, 3cM to form a closed cross-sectional structure with a hollow inside. Then, through holes 6 through which the cylindrical main body 11 of the vibration isolator 10 can be inserted are formed in the upper surface portions of the main body portions 3bM and 3cM, and four bolt through holes 7 are provided around the through holes 6. It is provided. Then, the bolt 19 is inserted from the inside of the lateral structural members 3b, 3c into the bolt insertion hole 7
The vibration isolator 10 is fixed by projecting it upward through the bolt insertion hole 18a of the mounting plate 18 and screwing the nut 20 into the bolt. In this state, a through hole is provided in the bottom plate 5a of the operator's cab 5, and the through hole is attached to the connecting member 15 so as to be in contact with the receiving plate 17, and the nut 21 is screwed into the screw portion of the connecting member 15. The driver's cab 5 is supported by the structure 1 of the upper revolving structure via the vibration isolator 10 by being screwed into.

As described above, the cab 5 is elastically supported by the structure 1 via the elastic member 13 which constitutes the vibration isolator 10, and when vibration occurs due to running of the vehicle, the connecting member 15 is formed. The movable plate 16 connected to the movable plate 16 moves up and down in the damping force generating chamber 14. At this time, the working fluid flows to the upper and lower parts partitioned by the movable plate 16, but this working fluid has a high viscosity. Also, since the flow path of the working fluid is restricted by the movable plate 16, the viscous resistance and flow resistance thereof exert a damping force for the vertical movement of the connecting member 15, and together with this and the elastic force of the elastic member 13, the cab. It is possible to prevent the vibration from being transmitted to 5.

[0009]

By the way, the above-mentioned conventional mounting structure of the vibration isolator has the following drawbacks.

First, the vibration isolator 10 has its mounting plate 18 fixed to the upper surface portion of the lateral structural member, but the three lateral members provided between the main structural members 2a and 2b. If the upper surfaces of the structural members 3a, 3b, 3c are not exactly in the same plane, the receiving plates 17 of the respective vibration isolation devices 10 will not be at the same height position, so that the driver's cab 5 is mounted in a tilted state. As a result, the load received by each vibration isolation device 10 is not uniform, and smooth vibration isolation support cannot be performed. Here, welding is performed to assemble the lateral structural members 3b and 3c into a can and to connect to the main structural member 2 after the can is assembled, but distortion or the like occurs during this welding.
Due to this welding strain and the like, it is extremely difficult to assemble all the lateral structural members 3a to 3c so that they are exactly at the same height position. Therefore, in practice, it is not possible to prevent variations in the height position of each vibration isolation device 10.

Second, in order to mount the vibration isolation device 10,
Since the through hole 6 is provided in the lateral structural members 3b and 3c having the closed cross-section structure, even if the through hole 6 is covered by the mounting plate 18 of the vibration isolator 10, this portion is not completely removed. Can not be sealed in. If this part cannot be sealed, rainwater will enter inside and rust will occur. Of course, if rust-preventive coating is applied, the generation of rust can be suppressed, but it is impossible to apply rust-preventive coating to the inside of the lateral structure members 3b and 3c having a closed cross-section structure.

Thirdly, in the first place, the lateral structural member is
From the viewpoint of riding comfort, etc., it has a closed cross-section structure because it is necessary to improve the rigidity in order to prevent low-frequency vibrations, and it can be said that the vibration isolator is mounted on such a structural member. Providing a through hole is not preferable because it lowers rigidity and strength accordingly.

The present invention has been made in view of the above points, and it is an object of the present invention to mount the vibration damping devices provided at a plurality of positions so that the height positions of the vibration damping devices can be accurately adjusted to each other. Moreover, it is possible to improve the rigidity and strength of the structural member to which the vibration isolator is attached.

[0014]

In order to achieve the above-mentioned object, according to the present invention, a horizontal structural member having a closed cross-section is stretched between a plurality of main structural members extending in the front-rear direction of a vehicle. Provided, in which a vibration isolator for vibration isolating and supporting the operator cab is mounted on the lateral structure member, a mounting bracket is fixedly attached to the side surface of the lateral structure member by welding means,
The feature is that the vibration isolator is fixedly provided on the mounting bracket.

[0015]

The lateral structural member constitutes the structural body of the entire upper revolving structure together with the main structural member, and the rigidity is improved by having the closed cross-section structure. A vibration-isolating device for vibration-isolating and supporting the driver's cab is supported by this horizontal structural member.
Instead of directly attaching to the lateral structural member, the mounting bracket is fixed by welding means, and the vibration isolator is attached to the mounting bracket. As a result, it is not necessary to provide a through hole in the horizontal structural member, and the strength and rigidity of the horizontal structural member can be improved. In addition, since no through hole is provided, the cavity inside the horizontal structural member can be sealed, preventing rainwater and the like from entering, and the inner surface of the horizontal structural member can be protected without special rust prevention coating. Does not rust.

[0016] Not all horizontal structural members can be assembled at the same height position due to distortion caused by welding performed when the horizontal structural members are assembled into the can or after connecting the main structural members after the can is assembled. Absent. Even if the horizontal structural member is not assembled with high precision, the height position can be easily controlled by adjusting the fixing position of the mounting bracket to the horizontal structural member. Therefore, by mounting the mounting brackets so as to be strictly at the same height position, it is possible to make all the vibration isolation devices at the same height position. As a result, the operator's cab is mounted exactly horizontally with respect to the structure.

[0017]

Embodiments of the present invention will now be described in detail with reference to the drawings. The structure of the upper revolving structure of the vehicle is substantially the same as that shown in FIG. 4. Therefore, the same or equivalent members as those in FIG. Is omitted. Further, since the same structure as that shown in FIG. 6 is used also for the configuration itself of the vibration isolator, the same reference numerals are used for the same or equivalent members as in FIG.

Thus, as shown in FIGS. 1 and 2, of the horizontal structural members 3 of the upper swing body 1, the horizontal structural members 3b and 3c having the closed cross-section structure are directly attached to the vibration isolator. 1
0 is not mounted, and a mounting bracket 30 is fixedly provided on the side surfaces of the main body portions 3bM and 3cM by welding means, and the vibration damping device 10 is attached to the mounting bracket 30.
Is installed. As shown in FIG. 3, the mounting bracket 30 includes a mounting portion 30a on which the vibration damping device 10 is mounted,
The fixing portion 30b is bent perpendicularly to the mounting portion 30a and welded and fixed to the lateral structural members 3b and 3c. A reinforcing portion 30c is provided so as to bridge between the mounting portion 30a and the fixed portion 30b.

Mounting portion 30a of the mounting bracket 30
A through hole 31 for inserting the cylindrical main body 11 of the vibration isolator 10 is bored therethrough, and bolt through holes 32 are provided at four locations around the through hole 31. Then, the bolt 19 is inserted from below the bolt insertion hole 32. To mount the vibration isolator 10, the cylindrical main body 11 of the vibration isolator 10 is inserted into the through hole 31 to be attached. The plate 18 is brought into contact with the mounting portion 30, and the bolt insertion hole 18a provided in the mounting plate 18 is aligned with the bolt insertion hole 32. Then, the bolt 19 is projected upward from the lower side, and the nut 20 is fixed. It can be attached by screwing.

The present embodiment is constructed as described above, and the lateral structure members 3b, 3c having a closed cross-section structure.
Since the through hole for mounting the vibration isolation device 10 is not provided in the, the lateral structural members 3b and 3c can have sufficient rigidity and strength, and the function as the structural body 1 is fully appreciated. By virtue of the improved rigidity, it is possible to prevent low frequency vibration from occurring in the cab 5 when the cab 5 is mounted and the vehicle is traveling, and the ride comfort of the operator is improved. There is no danger of getting worse. Further, since the horizontal structural members 3b and 3c can be made into a closed structure, there is no risk of rainwater or the like entering, so there is no risk of rusting even without anti-rust coating.

Since the mounting brackets 30 are fixed to the side surfaces of the horizontal structural members 3b and 3c by welding means, after the horizontal structural members 3b and 3c are assembled into a can,
After being connected to the main structural member 2, this mounting bracket 30 can be welded. Therefore, the fixing portion 30b of the mounting bracket 30 can be welded to an arbitrary position, so that the position of the mounting bracket 30 is adjusted so that the height positions of the receiving plates 17 of all the vibration damping devices 10 are accurately aligned. It becomes possible to weld in the state. As a result,
When the bottom plate a of the cab 5 is placed on the receiving plate 17, the flatness can be accurately obtained without tilting. As a result, all the vibration damping devices 10 can bear the load evenly, and the good vibration damping function can be surely exhibited.

Here, the fixing portion 30 of the mounting bracket 30
By using b as a wide surface to a certain extent and welding the entire circumference of the edge portion, the mounting bracket 3
0 is firmly fixed to the lateral structural members 3b and 3c. Moreover, since the reinforcing portion 30c is provided so as to extend between the fixing portion 30b and the mounting portion 30a, the connecting portion of the mounting portion 30a to the fixing portion 30b is not deformed by the load. Moreover, of the loads received by the entire structure 1, the load on the driver's cab 5 is not so large, and even if the mounting bracket 30 is fixed to the horizontal structural members 3b and 3c by welding in this manner, sufficient strength is achieved. Hold. On the other hand, what is particularly required for the lateral structural member 3 is that the member constituting the structure 1 is required to have extremely high rigidity against torsion, bending, etc. It is necessary to give strength and rigidity to withstand a load 10 times or more than the load for supporting the operator's cab 5, so that the lateral structural member 3 can sufficiently exert its function as a structural body. The horizontal structure member 3 is provided with no through holes that lead to a reduction in strength, and the vibration isolation device 10 that supports the operator cab 5, which has a relatively light load, is mounted on the horizontal structure member 3 by welding. By providing the structure 30 in the upper revolving structure, the structure 1 in the upper revolving structure can have an extremely rational structure.

In the above-described embodiment, the vibration isolator attached to the mounting bracket is fixed by four bolts, but it may be fixed by two thick bolts. . Further, although the vibration isolator is provided at three locations on the three horizontal structural members, it may be provided only at four locations depending on the load of the cab. Further, since the lateral structural member located at the forefront does not have a closed cross-section structure, the vibration isolator attached thereto has a structure in which a through hole is directly provided in this lateral structural member and the structure is directly attached to this lateral structural member. However, it may be configured such that a mounting bracket for mounting the anti-vibration device is also provided on the horizontal structural member located at the most distal end, and when the horizontal structural member itself also has a closed cross-section structure. The vibration proof device may be attached to the mounting bracket.

[0024]

As described above, according to the present invention, the mounting bracket for mounting the vibration isolator is fixedly provided on the lateral structural member having the closed cross-section structure by the welding means. Since it is not necessary to form a through hole that leads to a decrease in strength in this lateral structure member and the inside can be hermetically sealed, it is possible to reliably prevent generation of rust due to intrusion of rainwater and the like. Even if welding distortion occurs at the time of forming and assembling, it does not affect the mounting position of the anti-vibration device, so that there is an effect such that the driver's cab can be reliably anti-vibrated in a planar shape.

[Brief description of drawings]

FIG. 1 is a plan view of a driver's cab vibration-isolating support device according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line XX of FIG.

FIG. 3 is an external view showing a configuration of a mounting bracket on which a vibration isolation device is mounted.

FIG. 4 is a structural explanatory view of an upper swing body of a hydraulic excavator as a construction machine.

FIG. 5 is a plan view of a driver's cab anti-vibration support device according to the prior art.

6 is a sectional view taken along line YY of FIG.

[Explanation of symbols]

 1 structure 2,2a, 2b main structural member 3,3a, 3b, 3c lateral structural member 5 driver's cab 10 vibration damping device 18 mounting plate 18a bolt insertion hole 19 bolt 30 mounting bracket 30a mounting portion 30b fixing portion 30c reinforcing portion 31 Through hole 32 Bolt insertion hole

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Kenichi Kimura Inventor Kenichi Kimura 650 Jinrachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory

Claims (1)

[Claims] 1. A horizontal structural member having a closed cross-section is stretched between main structural members extending in the front-rear direction of a vehicle, and the horizontal structural member is provided with a vibration preventive support for vibration-proofing and supporting the cab. A construction in which a vibration device is mounted, wherein a mounting bracket is fixedly provided on the side surface of the lateral structural member by welding means, and the vibration damping device is fixedly provided on the mounting bracket. Machine driver's cab anti-vibration support device.