JPH0858451A - Work machine provided with operator cab - Google Patents

Abstract

PURPOSE: To improve the comfortableness in driving by preventing an operator cab from vibrating back and forth and right and left to cause pitching or rolling, and also, attenuating its vertical vibration. CONSTITUTION: This work machine is so constituted as to support an operator cab body 21 on a turning frame 4 in the vicinity of the center of gravity G by elastically coupling the support face 25 of a support stand 24 erected on a turning frame 4 and the seat 29 of a hollow projection 28 provided integrally on the floor board 26 of the operator cab body 21 through each shock absorbing support 32. Hereby, even in the case that back and forth or right and left vibration occurs in the operator cab body 21 during work, etc., the moment working on the center of gravity G of the operator cab body 21 caused by this vibration can be reduced, and the operator cab body 21 can be prevented from causing pitching or rolling, and besides the vertical vibration can be attenuated by the shock absorbing support 32, so that the comfortableness in driving can be remarkably improved.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a working machine with a driver's cab such as a hydraulic excavator, and more particularly to a working machine with a driver's cab for absorbing vibration transmitted from a frame of the working machine to the driver's cab.

[0002]

2. Description of the Related Art A hydraulic excavator is shown as an example of a conventional working machine with a cab in FIGS.

In the figure, 1 is a lower traveling structure, 2 is a turning device, 3
Is an upper revolving structure which is rotatably mounted on the lower traveling structure 1 via the revolving device 2 and constitutes a working machine main body. The upper revolving structure 3 is a revolving frame 4 as a frame having a frame structure. , A machine room 5 provided on the swivel frame 4
And an operation including a driver's cab main body 8 to be described later, which is provided on the front left side of the machine room 5 on the revolving frame 4 and various operating levers and instruments provided in the operator's cab main body 8. It comprises a chamber 6 and a counterweight 7 provided at the rear of the revolving frame 4 which is located on the rear side of the machine room 5. The counterweight 7 balances the entire upper revolving structure 3 with a working device 12 described later. It is designed to let you.

Reference numeral 8 denotes a driver's cab main body which is disposed on the swivel frame 4 and constitutes a main body of the driver's cab 6. The operator's cab main body 8 is formed as a box-shaped cab box as shown in FIG. There is. A door 9 is provided on the left side surface of the driver's cab body 8, and a floor plate 10 forming a part of the driver's cab body 8 is disposed on the lower surface side of the driver's cab body 8.

The buffer supports 11 elastically support the driver's cab body 8 on the swivel frame 4, and each of the buffer supports 11 includes a vibration-proof rubber, a spacer, a stopper, etc. (all shown). No)). The buffer supports 11 are separated from each other, for example, between the floor plate 10 of the cab body 8 and the revolving frame 4 in the front-rear direction and the left-right direction, for a total of four.
The number (only two are shown) is provided so as to attenuate the transmission of the vibration from the revolving frame 4 to the cab body 8.

Reference numeral 12 denotes a working device provided in the front part of the upper swing body 3, and the working device 12 can be lifted and lowered on a highly rigid bracket portion (not shown) forming a part of the swing frame 4. A boom 12A provided, an arm 12B provided at the tip of the boom 12A so as to be able to move up and down, and the arm 1
A backhoe type bucket 12C rotatably provided at the tip of 2B. These boom 12A, arm 12B and bucket 12C are operated by a boom cylinder 12D, an arm cylinder 12E and a bucket cylinder 12F, respectively. There is. The working device 12 is used for boom cylinders 12D, when excavating earth and sand.
Boom 12A and arm 1 by arm cylinder 12E
While raising and lowering 2B, the bucket cylinder 12F rotates the bucket 12C, and the bucket 12C excavates earth and sand and the like.

In the hydraulic excavator constructed as above,
A prime mover and a hydraulic pump (not shown) driven by the prime mover are provided in a machine chamber 5 of the upper swing body 3, and pressure oil discharged from the hydraulic pump is supplied to a traveling hydraulic motor of the lower traveling body 1 ( (Not shown) and the cylinders 12D, 12E, 12F, etc. of the working device 12 are supplied to and discharged from the cylinders 12D, 12E, 12F, etc., to operate them so as to drive the vehicle and excavate earth and sand.

The cushioning supports 11 provided between the floor plate 10 of the cab body 8 and the swivel frame 4 are swung by vibrations from the engine, vibrations during traveling, and vibrations due to excavation reaction force during work. Vibration transmitted from the frame 4 side to the driver's cab body 8 is buffered by a vibration-proof rubber to reduce vibration and noise at this time so as not to deteriorate the riding comfort of the driver's cab 6.

[0009]

By the way, in the above-mentioned prior art, the floor plate 1 of the operator cab body 8 is mounted on the revolving frame 4.
, For example, four buffer supports 11, 11, ... Are arranged to prevent external vibration from being transmitted to the operator's cab 6, but in practice There is a problem based on natural frequencies.

That is, the weight W of the operator's cab 6 and each buffer support 1
Assuming that the total spring constant of 1 is k and the gravitational acceleration is G, the vertical natural frequency f of the cab 6 is

[0011]

[Equation 1] It is represented by.

Here, the driver's cab body 8 is approximated by a one-degree-of-freedom vibration model as shown in FIG. 7, and when a forced vibration a ₀ cos ωt having an amplitude a ₀ is applied in the vertical direction from below,
When the amplitude of the vibration transmitted to the operator's cab 6 is a, the vibration transmission rate τ is

[0013]

[Equation 2] It is represented by.

At this time, the relationship between the frequency ratio η and the vibration transmissibility τ is that the frequency ratio η is η = 1 as shown by the characteristic line in FIG.
The vibration increases due to resonance before and after, and the frequency ratio η increases, and if the frequency ratio is √2 or more, the vibration transmissibility τ is 1
It can be seen that the vibration becomes less likely to be transmitted as follows.

The weight W of the entire cab 6 is 400 to
500 kg, the total spring constant k of each buffer support 11 is 2
Under the condition of 000 to 8000 kgf / cm, the natural frequency f of the operator's cab 6 is about 20 to 45 Hz from the above equation 1.

However, the vibration frequency generated when the hydraulic excavator operates is usually included within the range of the natural frequency that can be taken by the operator cab 6 as described above. The difference from the natural frequency of the operator's cab 6 becomes small, and the value of the above-mentioned frequency ratio η approaches η = 1. As a result, there is a problem in that the driver's cab 6 vibrates greatly due to the vibration generated when the hydraulic excavator operates, and the riding comfort deteriorates.

The revolving frame 4 to which the cab 6 is attached is supported in a cantilever state with respect to the revolving device 2, and the cab main body 8 is provided between the floor plate 10 and the revolving frame 4. Since it is supported on the revolving frame 4 by each buffer support 11, the distance between the supporting position of the cab main body 8 on the revolving frame 4 and the center of gravity of the cab main body 8 becomes relatively large, and the revolving frame 4 When the vibration propagates to the cab main body 8 via 4, the moment acting on the cab main body 8 due to the vibration tends to increase. Therefore, in addition to the vertical vibrations described above, vibrations in the front-rear direction (pitching) and vibrations in the left-right direction (rolling) are also propagated due to torsional vibrations that act on the revolving frame 4. . Here, for example, the natural frequency of the operator's cab 6 due to rolling takes a value around 10 Hz, which is lower than the natural frequency due to vertical vibration, but the natural frequency around 10 Hz is the drive wheel during traveling of the hydraulic excavator. When the hydraulic excavator travels, the driver's cab 6 vibrates greatly due to rolling and the riding comfort deteriorates when the hydraulic excavator travels.

On the other hand, for example, when the spring constant k of each buffer support 11 is set to be small and the natural frequency f in the vertical direction of the cab 6 is set to be small, the cab 6 Although the vibration in the up and down direction can be dampened, pitching and rolling increase.

As described above, when the driver's cab 6 undergoes large pitching or rolling, not only the riding comfort is deteriorated, but also the driver's cab body 8 is largely tilted due to the pitching or rolling during work, etc. For example, a bracket portion (not shown) provided on the revolving frame 4 to support the working device 12 interferes with the cab body 8,
The cab body 8 may be damaged. Therefore, in the conventional technique, the stopper provided on each cushion support 11 collides with the swivel frame 4 to regulate the amount of deformation of the antivibration rubber. Even if it works, it is possible to prevent the driver's cab body 8 from being greatly tilted.

However, when the stopper of each buffer support 11 collides with the swivel frame 4, the vibration transmitted to the swivel frame 4 is directly transmitted to the driver's cab body 8, so that the riding comfort of the cab body 8 is improved. Has a problem that it becomes significantly worse.

The present invention has been made in view of the above-mentioned problems of the prior art. It is possible to prevent the driver's cab main body from vibrating back and forth, left and right to cause pitching and rolling, and to prevent vertical vibration of the cab main body. It is also an object of the present invention to provide a working machine with a cab that can effectively reduce the noise and improve the riding comfort during work.

[0022]

In order to solve the above-mentioned problems, a working machine with a cab according to the present invention comprises a frame of a working machine body and a floor board provided on the lower surface of the frame. It is composed of a room main body and a driver's seat located inside the operator's room main body and arranged on the floor plate.

The feature of the configuration adopted by the invention of claim 1 is that it stands upright from the frame in the vicinity of the center of gravity of the cab body in order to support the cab body near its center of gravity. A support base on which a support surface is formed, a seat portion provided on the cab main body so as to face the support surface portion of the support base, and between the seat portion and the support surface portion of the support base. And a buffer support that elastically damps transmission of vibrations from the frame to the cab body.

Further, as in the invention described in claim 2,
The support base is formed in a convex shape so as to project upward from the frame, and the seat portion is integrally provided on the floor plate so as to cover the support base from above, and It can be formed on the upper end side of the hollow protrusion that protrudes toward the center of gravity.

Further, as in the invention described in claim 3, it is desirable that the driver's seat is arranged on the seat portion.

Further, as in the invention described in claim 4, a lower cushion support having a spring constant different from that of the cushion support is provided between the frame and the floor plate of the cab body. it can.

[0027]

With the above structure, according to the first aspect of the present invention, the support surface portion of the support stand erected on the frame and the seat portion provided on the cab main body are coupled via the buffer support. Since the driver's cab main body can be supported on the frame near its center of gravity, even if vibration is applied to the driver's cab main body in the front-back and left-right directions during work, the moment that acts on the center of gravity of the driver's cab due to this vibration Can be reduced, and the cab body can be prevented from pitching or rolling during work. Moreover, each of the cushioning supports interposed between the support surface portion of the support base and the seat portion can also dampen the vertical vibration acting on the cab body.

Further, according to the second aspect of the present invention, a hollow projecting portion is integrally provided on the floor plate of the operator's cab body so as to cover the convex support base from the upper side, and the hollow protrusion is provided toward the center of gravity of the operator's cab body. Since the receiving portion is provided on the upper end side of the projecting hollow protruding portion and the receiving portion is connected to the supporting surface portion of the supporting base through the buffer support, the receiving base operates on the supporting base of the frame. The room main body can be reliably supported at a position close to its center of gravity, and vibration of the cab main body can be reliably reduced.

Further, according to the third aspect of the present invention, by providing the driver's seat on the seat near the center of gravity of the driver's cab main body, the driver's cab main body is subjected to longitudinal and lateral vibrations. Also, it is possible to prevent the driver's seat from pitching or rolling due to this vibration.

Further, according to the structure of claim 4, by providing the lower cushion support between the floor plate of the cab body and the frame, the cab body can be supported on the frame in a wide area range. Therefore, for example, even when a large shock or the like is applied to the cab body from the outside and the buffer support is largely deformed and the cab body is inclined, the cab body can be kept in a stable posture. At this time,
If the spring constant of the lower cushion support is set smaller than the spring constant of the cushion support, the driver's cab main body can be maintained in a stable posture at all times, and the vertical vibration acting on the cab main Can also be attenuated.

[0031]

Embodiments of the present invention will be described below with reference to FIGS. In the embodiments, the same components as those of the above-described conventional technique are designated by the same reference numerals, and the description thereof will be omitted.

First, a first embodiment of the present invention will be described with reference to FIGS.

In the figure, reference numeral 21 denotes a driver's cab main body which is arranged on the revolving frame 4 and constitutes a main body of the driver's cab 22,
As shown in FIG. 1, the operator cab body 21 is formed by pressing and welding a thin steel plate to form a rectangular ceiling portion 21A extending in the front-rear direction and an upper and lower intermediate portion projecting forward. According to the shapes of the rear surface portion 21C and the front surface portion 21B, and the vertically long rectangular rear surface portion 21C substantially vertical to the revolving frame 4. It is formed as a box-shaped cab box including substantially pentagonal left and right side surface portions 21D, 21D and the like provided with protruding portions.

The left side surface portion 21D of the operator's cab body 21
A door 23 is provided so as to be openable and closable, and a floor plate 26 which will be described later and constitutes a part of the cab body 21 is provided on the lower surface side of the cab body 21 via a floor plate bracket 21E.

Reference numeral 24 denotes a support stand that is erected on the revolving frame 4. The support stand 24 has a high rigidity with a convex shape and a closed upper end side, for example, by bending a steel plate or the like. The U-shaped box is formed, and the lower end side thereof is fixed to the upper surface portion 4A of the revolving frame 4 by welding or the like. Then, the upper end side of the support base 24 extends to a height position corresponding to the center of gravity G of the cab main body 21 (position above the upper surface portion 4A of the revolving frame 4 by a distance T), and is buffered as described later. The support surface portion 25 supports the cab main body 21 via the support body 32, and the support surface portion 25 has four mounting holes 25A, 25A, ... For mounting the buffer support body 32 as shown in FIG. Has been drilled.

Reference numeral 26 denotes a floor plate provided on the lower surface side of the cab main body 21, and the floor plate 26 is a floor surface portion 27 attached to the cab main body 21 via a floor plate bracket 21E, and a central portion of the floor surface portion 27. And a hollow projecting portion 28 projecting upward. Here, the hollow protruding portion 28 has a rectangular parallelepiped shape with a high rigidity, which has a U-shaped cross section so as to cover the support base 24 from the upper side, for example, by pressing a plate material for the floor plate 26. Are formed as protrusions of the support base 24 and
The two outer surfaces face each other at equal intervals. Then, the upper end side of the hollow protrusion 28 is
The seat 29 is located inside the cab main body 21, reaches the vicinity of the center of gravity G, and faces the support surface 25 of the support base 24. Further, the seat portion 29 is provided with four mounting holes 29A, 29A, ... For mounting the buffer support 32.

Reference numeral 30 denotes a driver's seat pedestal disposed in the driver's cab main body 21 and disposed on the seat portion 29. The driver's seat pedestal 30 is formed of, for example, a steel plate in a rectangular parallelepiped box shape, and is seated. Part 29
The four bolt insertion holes 30A, 3 are provided on the lower surface side facing the
0A, ... Are drilled. A driver's seat 31 is attached to the upper surface side of the driver's seat base 30.

32, 32, ... Support surface portions 2 of the support base 24.
5, which is provided between the seat 5 and the seat 29 of the hollow protrusion 28, and which elastically supports the cab body 21 on the swivel frame 4.
As shown in FIG. 3, each buffer support 32 is roughly composed of a pair of anti-vibration rubbers 33, 33, a pair of stoppers 34, 34, a spacer 35, etc., which will be described later. ing.

Reference numerals 33 and 33 denote anti-vibration rubbers. Each anti-vibration rubber 33 is made of an elastic material such as synthetic rubber into a short and thick columnar shape, and a central portion thereof has an insertion hole extending in the axial direction. 33A is drilled. Then, the anti-vibration rubber 33
Are arranged so as to sandwich the support surface portion 25 from the vertical direction.

Reference numerals 34 and 34 denote bottomed cylindrical stoppers for sandwiching the anti-vibration rubbers 33 from both sides in the vertical direction.
4 is a disk-shaped member having a diameter larger than that of the vibration-proof rubber 33, and has a bottom portion 34B having a bolt insertion hole 34A formed at the center thereof, and an axially extending portion from the outer peripheral side of the bottom portion 34B. 33
And a tubular portion 34C having a shorter length than
An opening 34D is formed on the tip side of the cylindrical portion 34C. The stoppers 34 are arranged so as to sandwich the supporting surface portion 25 with the anti-vibration rubbers 33 interposed therebetween, and the opening 34D of each stopper 34 is spaced from the supporting surface portion 25 by a gap S of, for example, about 2 to 3 mm. By facing each other, the operator cab main body 21 supported on the revolving frame 4 via the respective cushioning supports 32 rolls laterally (rolling) in the left-right direction over the gap S, or pitches longitudinally in the front-back direction. (Pitching) is regulated.

Reference numeral 35 denotes a spacer made of a metal cylinder having a bolt insertion hole 35A in the axial direction.
Has a lengthwise intermediate portion loosely fitted in each mounting hole 25A formed in the support surface portion 25, and upper and lower ends thereof are fitted in the insertion holes 33A of each anti-vibration rubber 33. Also, the spacer 3
The upper and lower end surfaces of 5 are in contact with the bottom portions 34B of the stoppers 34, respectively.

Reference numeral 36 is a mounting bolt, and the bolt 36 is inserted downward from each bolt insertion hole 30A formed in the driver's seat pedestal 30 and mounted in each seat 29 of the floor plate 26. Hole 29A and spacer 35 bolt insertion hole 35A
Is inserted inside. The lower end side of the bolt 36 projects from the lower side of the bottom portion 34B of the stopper 33 located in the support base 24, and the nut 37 is screwed onto the lower end side of the bolt 36 to tighten the support surface portion of the support base 24. 25 and the seat portion 29 of the hollow projecting portion 28 are coupled to each other via the buffer supports 32, and a driver seat 30 is attached to the seat portion 29.

.. are located at the four corners of the cab body 21 and are provided between the floor surface portion 27 of the floor plate 26 and the revolving frame 4 and four lower buffer supports (only two are shown). Each of the lower cushioning supports 38 is similar to each of the above-mentioned cushioning supports 32, and has a pair of anti-vibration rubbers 39, 39 and a bottomed cylinder that holds the anti-vibration rubbers 39 from both sides in the vertical direction. -Shaped stoppers 40, 40, a cylindrical spacer (not shown) fitted in each of the anti-vibration rubbers 39, a bolt 41 inserted into the stopper 40, and a nut screwed into the bolt 41. However, the spring constant of each anti-vibration rubber 39 is set to be smaller than the spring constant of each anti-vibration rubber 33 of the buffer support 32.

The lower cushioning supports 38 are arranged in such a manner that the anti-vibration rubbers 39 and the respective stoppers 40 are arranged so as to sandwich the upper surface 4A of the revolving frame 4 in the cab main body 21.
Of the floor plate bracket 21E, the floor surface portion 27 of the floor plate 26, and the spacers, and the bolt 41 is inserted into the swivel frame 4.
The swivel frame 4 and the floor plate 26 of the operator's cab body 21 are elastically coupled to each other by screwing and tightening the nut 42 on the lower end side of the bolt 41 protruding from the stopper 40 located inside.

In this way, in this embodiment, the support 24 is erected on the revolving frame 4, and the floor plate 26 of the cab body 21 is integrally provided with the hollow protrusion 28.
The support surface portion 25 of the support base 24 and the seat portion 2 of the hollow protruding portion 28
By connecting 9 and 9 via each buffer support 32,
The lower cushion support bodies 3 elastically support the cab body 21 on the swivel frame 4 in the vicinity of the center of gravity G, and the four corners of the cab body 21 have lower spring constants than the cushion supports 32.
It is configured to be supported on the revolving frame 4 via 8.

The hydraulic excavator provided with the operator cab 22 constructed as described above generates vibrations from the engine during operation, vibrations during traveling, and excavation reaction force during operation. 4 propagates to the cab main body 21 via the support base 24 and the respective buffer supports 32, but the cab main body 21 is located near the center of gravity G of the hollow seat 28 provided on the floor plate 26 by the seat 29. At each buffer support 32
Since it is supported on the support surface portion 25 of the support base 24 via the, the moment acting on the center of gravity G of the cab body 21 due to the vibration can be reduced. Therefore, the vibration propagating from the swivel frame 4 to the support base 24 is reduced while propagating to the cab body 21 via the respective cushioning supports 32, which prevents the cab body 21 from pitching or rolling. It can be prevented and the riding comfort at the time of work can be improved.

Further, a supporting base 24 is erected on the revolving frame 4, a hollow projecting portion 28 is provided on a floor plate 26 of the cab main body 21, and a supporting surface portion 25 provided on the supporting base 24 and the supporting surface portion 25. The seat portion 29 of the hollow protruding portion 28 facing the above is coupled via each buffer support 32, so that the cab main body 21 is elastically supported in the vicinity of its center of gravity G on the revolving frame 4. Can be installed at

Further, by connecting the four corners of the cab body 21 to the revolving frame 4 via the respective lower cushion supports 38, the cab body 21 is wide at the front, rear, left and right corners. It can be reliably supported on the revolving frame 4 with an area range. Therefore, for example, when a large shock is applied to the driver's cab main body 21 from the outside, each buffer support 3
Even when the vibration damping rubber 33 of 2 is largely deformed and the driver's cab body 21 is inclined, the driver's cab body 21 can be kept in a stable posture by the respective lower cushion supports 38. At this time, the spring constant of the anti-vibration rubber 39 that constitutes each lower cushion support 38 is equal to the spring constant of the anti-vibration rubber 33 that constitutes each cushion support 32.
Since it is set to be smaller than the spring constant of, the vertical vibration acting on the cab body 21 can be damped.

Moreover, since it is possible to prevent the operator's cab main body 21 from being greatly tilted, the anti-vibration rubber 33 of each buffer support 32 is deformed and each stopper 34 collides with the support surface portion 25 of the support base 24 and is damaged. In addition, it is possible to prevent each vibration-proof rubber 33 from being deformed and damaged beyond the elastic limit.

Furthermore, by disposing the driver seat 31 on the upper side of the seat portion 29, the driver seat 31 is moved to the driver's cab main body 21.
Since the positioning can be performed in the vicinity of the center of gravity G of the driver's cab, even if vibration is applied to the driver's cab main body 21 during the work, the driver's seat 31 can be prevented from pitching or rolling due to the vibration. It is possible to greatly improve the riding comfort of time.

Next, FIG. 4 shows a second embodiment of the present invention. In this embodiment, the same components as those in the first embodiment shown in FIGS. 1 to 3 described above are designated by the same reference numerals, and the description thereof will be omitted.

In the figure, reference numeral 51 denotes a driver's cab according to this embodiment, and the driver's cab 51 is the driver's cab 22 according to the first embodiment.
The driver's cab body 21, the support 24, the floor plate 26,
Although it is composed of the hollow projecting portion 28 and each cushioning support body 32 and the like, the configuration of the lower cushioning support body 53 provided between the floor surface portion 27 of the floor plate 26 and the turning frame 52 to be described later is the same as that of the first embodiment. Are different.

Reference numeral 52 denotes a revolving frame of the present embodiment. The revolving frame 52 has a frame structure as a whole substantially similar to the revolving frame 4 according to the first embodiment, but the revolving frame 52 has a lower beam portion 52A. And an upper beam portion 52B that reinforces the lower beam portion 52A. In the present embodiment, the lower beam portion 5 of the turning frame 52 is located at the lower end side of the support base 24.
It is fixed to 2A by welding or the like.

Reference numerals 53, 53, ... Denote lower cushioning supports provided at four corners of the cab body 21 and provided between the floor surface portion 27 of the floor plate 26 and the lower beam portion 52A of the revolving frame 52,
The lower cushioning supports 53 are shock absorbers 54 which are arranged in front of, behind, behind, left and right of the floor plate 26, respectively.
And integrally provided on each shock absorber 54,
The spring constant of each coil spring 55 is set to be smaller than the spring constant of the anti-vibration rubber 33 of each buffer support 32, for example. Has been done.
Then, each shock absorber 54 is provided with a damping force generating portion 54A projecting above the floor surface portion 27 of the floor plate 26,
Each damping force generating portion 54A is configured to damp the cab main body 21 when it vibrates in the vertical direction.

Reference numerals 56, 56, ... Show stoppers arranged at the four corners of the cab main body 21 in parallel with the respective lower cushioning supports 53, and the stoppers 56 serve as stroke ends of the shock absorbers 54. The shock absorbers 54 are prevented from excessively expanding and contracting together with the coil springs 55. The stoppers 56 prevent the cab main body 21 from vibrating beyond the stroke ends of the shock absorbers 54 when a large impact is applied to the cab main body 21 from the outside.

Also in the present embodiment configured as described above, the vibration generated during the work of the hydraulic excavator and propagated to the revolving frame 52 is transmitted through the buffer supports 32 through the respective buffer supports 32, as in the first embodiment. Reduced while propagating to the body 21,
As a result, it is possible to prevent the driver's cab main body 21 from causing pitching or rolling, and it is possible to improve the riding comfort during work.

Also, for example, when a large shock is applied to the driver's cab body 21 from the outside, the antivibration rubber 33 of each buffer support 32 is largely deformed and the driver's cab body 21 is inclined, The lower cushion supports 53 can keep the cab body 21 in an appropriate posture. At this time, in this embodiment, since each lower cushioning support body 53 is composed of the shock absorber 54 and the coil spring 55,
Even if a large shock is applied to the cab body 21 from the outside, the vibration acting on the cab body 21 due to this shock can be damped by the shock absorber 54, so that the cab body 21 should be kept in a stable posture. You can

Other constitutions and effects in this embodiment are the same as those in the first embodiment.

In each of the above-mentioned embodiments, the hydraulic excavator has been described as an example of the working machine provided with the operator's cab, but the present invention is not limited to this, and working machines such as wheel type hydraulic excavators and hydraulic cranes, for example. May be applied to.

[0060]

As described in detail above, according to the present invention as set forth in claim 1, a supporting surface portion of a supporting stand erected on a frame,
By elastically coupling the seating portion provided in the cab main body through the buffer support, the cab main body is supported on the frame near the center of gravity of the cab. Even when vibrations in the front-rear direction and the left-right direction are applied, the moment acting on the center of gravity of the cab main body due to the vibrations can be reduced, and the cab main body can be effectively prevented from pitching or rolling.

According to the second aspect of the present invention, a hollow projecting portion is integrally provided on the floor plate of the operator's cab body so as to cover the convex supporting base from above, and the center of gravity of the operator's cab main body is provided. Since the seat portion provided on the upper end side of the hollow projecting portion projecting toward the position is coupled to the support surface portion of the support base via the buffer support, the cab main body is located at a position close to its center of gravity. It can be reliably supported on the frame, and vibration of the driver's cab body during work can be reliably reduced.

Further, according to the invention of claim 3,
By providing the driver's seat on the seat part of the hollow protrusion near the center of gravity of the cab body, even if vibration in the front-rear direction or the left-right direction acts on the cab body, the driver seat is caused by this vibration. It can prevent pitching and rolling, and can greatly improve the riding comfort during work.

Further, according to the invention of claim 4, by providing the lower cushion support between the floor plate of the cab body and the frame, the cab body can be supported on the frame in a wide area range. Because of the configuration, even when a large shock is applied to the driver's cab body from the outside and the buffer support body is largely deformed and the driver's cab body is inclined, the driver's cab body can be kept in a stable posture. . Moreover, when the spring constant of the lower cushion support is set to be smaller than the spring constant of the cushion support, the vertical vibration acting on the driver's cab main body can also be damped, and a comfortable ride is always obtained. be able to.

[Brief description of drawings]

FIG. 1 is an external view of a broken main part showing a swivel frame of a hydraulic excavator, a driver's cab body, and the like according to a first embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II in FIG.

FIG. 3 is an enlarged vertical sectional view showing a buffer support in FIG.

FIG. 4 is an external view of a broken main part showing a swivel frame of a hydraulic excavator, a cab body, and the like according to a second embodiment of the present invention.

FIG. 5 is an external view showing a hydraulic excavator according to a conventional technique.

6 is a partially cutaway external view showing an enlarged view of a swivel frame, a cab body, and the like in FIG.

FIG. 7 is an explanatory diagram for analyzing vibration in a cab.

FIG. 8 is a characteristic diagram showing the relationship between the frequency ratio of forced vibration to the natural frequency of the cab and the vibration transmissibility.

[Explanation of symbols]

 4,52 Revolving frame (frame) 21 Driver's cab body 24 Supporting stand 25 Supporting surface part 26 Floor plate 28 Hollow protruding part 29 Receiving part 32 Buffer support 38,53 Lower buffer support

Claims (4)

[Claims] 1. A frame of a work machine main body, a driver's cab main body provided on the frame and provided with a floor plate on a lower surface side, and a driver's seat located on the floor plate inside the operator's cab main body. In a working machine with a driver's cab consisting of, in order to support the driver's cab main body near its center of gravity position, a support base that is erected upward from the frame and has a support surface portion formed near the center of gravity of the driver's cab main body, , A seat portion provided in the cab main body so as to face the support surface portion of the support base, and provided between the seat portion and the support surface portion of the support base, and vibration from the frame is driven. A working machine with a driver's cab, comprising: a buffer support that elastically buffers transmission to the room main body. 2. The support base is formed in a convex shape so as to project upward from the frame, and the seat portion is
The driver's cab according to claim 1, wherein the supporter is integrally provided on the floor plate so as to cover the supporter from the upper side, and is formed on an upper end side of a hollow protruding portion protruding toward the center of gravity of the operator's cab body. Working machine. 3. The working machine with a cab according to claim 1, wherein the driver's seat is arranged on the seat. 4. The cab according to claim 1, wherein a lower cushion support having a spring constant different from that of the cushion support is provided between the frame and the floor plate of the cab body. With working machine.