JPH0642012A - Cab of work machine - Google Patents

Abstract

(57) [Summary] [Purpose] To reduce the natural frequency of the driver's cab to improve riding comfort and prevent pitching and rolling in the driver's cab. [Structure] The floor plate 24 of the cab main body 22 includes a bottom plate 25 and a support plate 26 with vibration damping rubbers 33, 33, ...
And a lower cushioning support body 27 including a leaf spring 28 and a shock absorber 32 is provided between the revolving frame 21 and the support plate 26 on both left and right sides. The swivel frame 21 is provided with columns 34 near the corners 22F of the cab body 22, and the columns 34 and the cab body 2 are provided.
A laminated seismic isolation rubber 39 is provided between the second rear surface portion 22C and the rear surface portion 22C to buffer the longitudinal vibration with a large spring constant and to buffer the vertical vibration with a small spring constant.

Description

Detailed Description of the Invention

[0001]

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

[0002]

2. Description of the Related Art FIGS. 9 to 13 show a hydraulic excavator as an example of a conventional working machine with a cab.

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 main body of the working machine. The upper revolving structure 3 is a revolving frame 4 as a main body frame having a frame structure. A machine room 5 provided on the swivel frame 4, a machine room 5 located on the left side of the front part of the machine room 5 on the swivel frame 4, and a driver's cab body 8 and a driver's cab body 8 which will be described later. A driver's cab 6 including various operating levers and instruments provided, and a revolving frame 4 located behind the machine room 5.
The counterweight 7 is provided at the rear part of the upper part, and the counterweight 7 balances the entire upper swing body 3 with respect to a working device 17 described later.

Reference numeral 8 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 6. The driver's cab main body 8 is formed by pressing a thin steel plate and welding it. , A rectangular ceiling portion 8A extending in the front-rear direction, a substantially U-shaped front surface portion 8B in which an intermediate portion in the up-down direction protrudes forward, and a vertically long rectangular shape substantially vertical to the revolving frame 4. From the rear surface portion 8C and the substantially pentagonal left and right side surface portions 8D, 8D (only one is shown), etc., which are provided with forwardly projecting portions according to the shapes of the rear surface portion 8C and the front surface portion 8B. It is formed as a box-shaped cab box. A door 9 is provided on the left side surface portion 8D of the driver's cab body 8, and a floor plate 10 forming a part of the driver's cab body 8 is attached to the lower surface of the driver's cab body 8 via a floor plate bracket 8E. ing.

Reference numerals 11, 11, ... Show lower cushion supports that elastically support the cab main body 8 on the swivel frame 4, and each of the lower cushion supports 11 is, as shown in FIG. 12, a spacer 13, each stopper 14, and the like. The lower cushion supports 11 are provided between the floor plate 10 of the cab body 8 and the revolving frame 4 in the front and rear,
There are a total of four (only two are shown) spaced apart from each other on the left and right,
The vibration from the revolving frame 4 is attenuated so that it is transmitted to the cab body 8.

Reference numerals 12 and 12 denote anti-vibration rubbers. Each anti-vibration rubber 12 is formed of an elastic material such as synthetic rubber into a short and thick columnar shape, and its central portion has an axial direction as shown in FIG. An insertion hole 12A extending in the direction is formed. And
The anti-vibration rubbers 12 are arranged so as to be coaxial with the mounting holes 4B formed in the upper surface portion 4A of the revolving frame 4, and sandwich the upper surface portion 4A of the revolving frame 4 from above and below.

Reference numeral 13 denotes a spacer made of a metal cylinder having a bolt insertion hole 13A in the axial direction.
3, the middle portion in the longitudinal direction is loosely fitted in the mounting hole 4B of the revolving frame 4, and the upper and lower ends are the through holes 12 of the respective rubber vibration isolator 12.
It is fitted in A. The upper and lower end surfaces of the spacer 13 are in contact with the bottom portions 14B of the stoppers 14 described later.

Reference numerals 14 and 14 denote stoppers formed in a cylindrical shape with a bottom by press-molding a metal plate or the like, and each stopper 14 is a disk having a diameter larger than that of the vibration-proof rubber 12 as shown in FIG. Bottom portion 14B formed in a circular shape and having a bolt insertion hole 14A formed in the center, and a cylindrical portion extending axially from the outer peripheral side of the bottom portion 14B and having a length dimension shorter than that of the vibration isolating rubber 12. 14C, and the front end side of the cylindrical portion 14C is an opening 14D. The stoppers 14 are mounted so that the openings 14D are opposed to each other with the upper surface portion 4A of the revolving frame 4 interposed therebetween with the anti-vibration rubbers 12 interposed therebetween, and the upper and lower anti-vibration rubbers 12 are covered from the outside. Has been.

The bolts 15, 15 ... Are inserted into the respective bolt insertion holes 8F of the floor plate bracket 8E from the inside of the operator's cab main body 8, and the bolt insertion holes 13A of each spacer 13 and the floor plate. 10 bolt insertion holes 10A,
The inside of each mounting hole 4B of the upper surface portion 4A of the swivel frame 4 is extended, and the lower side of the lower cushion support 11, that is, the stopper 14
The operator's cab main body 8 is positioned on the revolving frame 4 by screwing and tightening the nut 16 from the bottom of the bottom portion 14B.

Reference numeral 17 denotes a working device provided in the front portion of the upper swing body 3, and the working device 17 is a boom provided on a high-rigidity bracket portion 4C forming a part of the swing frame 4 so as to be able to move up and down. 17A, an arm 17B provided at the tip of the boom 17A so as to be able to move downward, and a backhoe type bucket 17 provided at the tip of the arm 17B so as to be rotatable.
C, and these boom 17A, arm 17B,
The bucket 17C is operated by a boom cylinder 17D, an arm cylinder 17E, and a bucket cylinder 17F, respectively. Then, when excavating earth and sand or the like, the working device 17 rotates the bucket 17C by the bucket cylinder 17F while raising and lowering the boom 17A and the arm 17B by the boom cylinder 17D and the arm cylinder 17E, and the earth and sand by the bucket 17C. Is to be drilled.

In the hydraulic excavator constructed as above,
A prime mover and a hydraulic pump (not shown) driven by the prime mover are provided in the machine room 5 of the upper swing body 3, and the pressure oil discharged from the hydraulic pump is used for the traveling hydraulic motor of the lower traveling body 1 ( (Not shown) and the cylinders 17D, 17E, 17F, etc. of the working device 17 are supplied to and discharged from the cylinders 17D, 17E, 17F, etc., thereby operating them so as to drive the vehicle and excavate earth and sand.

The lower cushioning supports 11 provided between the floor plate 10 of the cab body 8 and the revolving frame 4 are subject to vibrations from the engine, vibrations during traveling, vibrations due to excavation reaction force during work, etc. The vibrations transmitted from the turning frame 4 side to the driver's cab main body 8 are buffered by the respective vibration isolating rubbers 12 to reduce vibration and noise at this time so as not to deteriorate the riding comfort of the driver's cab 6.

Further, as shown in FIG. 11, each lower cushioning support 11 has a gap S of about 2 to 3 mm between the opening 14D of each stopper 14 and the upper surface 4A of the revolving frame 4.
The driver's cab body 8 is restricted from rolling (rolling) to the left or right beyond the gap S, so that the driver's cab body 8 becomes a peripheral member such as the boom cylinder 17D. It is designed to prevent collisions and damage accidents.

[0014]

By the way, in the above-mentioned prior art, for example, four lower cushion supports 11, 11, are provided on the upper surface 4A of the revolving frame 4 and the floor plate 10 of the cab body 8. Are arranged to prevent external vibration from being transmitted to the cab 6, but there are the following problems.

That is, assuming that the weight W of the driver's cab 6, the total spring constant k of each lower cushion support 11 and the gravitational acceleration G, the natural frequency f of the driver's cab 6 is

[0016]

[Equation 1] It is represented by.

Here, the operator's cab body 8 is approximated by a one-degree-of-freedom vibration model as shown in FIG. 12, and the amplitude a _{0 is applied} from the lower side.
When the forced vibration a ₀ cosωt of is applied in the vertical direction (Z-axis direction), and the amplitude of the vibration transmitted to the cab 6 is a, the vibration transmissibility τ is

[0018]

[Equation 2] η: Frequency ratio ζ: Damping ratio ω _n : Natural angular frequency C: Damping coefficient C _c : Critical damping coefficient

When this is shown as a characteristic diagram, the frequency ratio η
The relationship between the vibration transmissibility τ and the vibration transmissibility τ is as shown in the characteristic line in FIG. 13. When the frequency ratio η is around η = 1, the vibration increases due to resonance, and when the frequency ratio η is large, the vibration transmissibility τ is large. It can be seen that is less than 1 and the vibration is less likely to be transmitted.

The weight W of the entire cab 6 is 400 to
500 kg, total spring constant k of each lower buffer support 11
Is 2000 to 8000 kg / cm, the above formula 1
Therefore, the natural frequency f of the cab 6 is about 20 to 45 Hz.

However, vibrations of about 20 to 45 Hz are included in many vibrations during the operation of the hydraulic excavator, and when the natural frequency f of the operator's cab 6 is in the above range, the frequency ratio η approaches η = 1. However, there is a problem that the vibration transmissibility τ becomes large and the riding comfort of the cab 6 is deteriorated.

On the other hand, if the spring constant k of each lower buffer support 11 is reduced in order to lower the natural frequency f, the vibration in the vertical direction can be damped, but the cab 6 moves in the front-back direction (Y
The pitching that vibrates in the axial direction and the rolling that vibrates the cab 6 in the left-right direction (the X-axis direction) become large, and the riding comfort deteriorates.

When the pitching or rolling becomes large, the cab main body 8 is moved to the boom cylinder 17
Since a collision accident occurs due to collision with a peripheral member such as D, the gap S between the opening 14D of each stopper 14 and the upper surface 4A of the revolving frame 4 is set to, for example, 2 to 2 as shown in FIG.
When the cab main body 8 vibrates beyond the gap S, the opening 14D of each stopper 14 collides with the upper surface 4A of the revolving frame 4 and the vibration from the revolving frame 4 is set to about 3 mm. There is a problem that it is directly transmitted to the main body 8 and the riding comfort of the driver's cab 6 becomes very poor.

The present invention has been made in view of the above-mentioned problems of the prior art. The present invention effectively prevents the cab body from vibrating in the front, rear, left, and right directions to cause pitching and rolling. It is also an object of the present invention to provide a working machine cab capable of effectively damping vertical vibrations and improving riding comfort.

[0025]

The features of the structure adopted by the present invention to solve the above-mentioned problems are that each lower cushion support is composed of a leaf spring and a shock absorber, and the body frame has a driver's cab. A vibration restricting body is provided near the corners on the rear side of the main body, and a large spring constant is provided between the vibration restricting body and the driver's cab body to prevent horizontal vibration of the operator's cab main body. The purpose is to provide an elastic cushioning body that cushions vertical vibrations with a small spring constant.

In this case, it is preferable that the elastic cushioning body is made of laminated seismic isolation rubber obtained by laminating a rubber plate and a metal plate each having a predetermined plate thickness.

Further, the floor plate of the operator's cab body is composed of upper and lower floor plate parts having a double structure, and between the respective floor plate parts,
It is preferable to provide an elastic member that elastically supports the operator's cab main body on the lower floor plate portion and buffers vibration of a higher frequency than the leaf spring.

[0028]

With the above structure, if the leaf spring of the lower cushioning support is formed by stacking a plurality of spring plates, the vertical vibration of the cab main body is quickly attenuated by the friction when the plate springs are bent. In particular, if the spring constant of the leaf spring is set to be relatively small, the natural frequency of the cab body can be reduced and the vibration transmitted to the cab can be reduced. Then, the vibration damping of the driver's cab body in the front-rear direction and the left-right direction can be restricted to a small level by the elastic shock absorber made of, for example, laminated seismic isolation rubber.

If elastic members are provided between the upper and lower floor plate portions of the operator's cab body, the elastic members can absorb vibrations at high frequencies that cannot be absorbed by the leaf springs of the lower buffer support. You can

[0030]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment 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, FIGS. 1 to 4 show a first embodiment of the present invention.

In the figure, reference numeral 21 denotes a revolving frame serving as a main body frame of the upper revolving structure 3. The revolving frame 21 has substantially the same structure as that of the revolving frame 4 described in the prior art, but the revolving frame 21 does not have the same structure. On the upper surface portion 21A, a concave accommodation portion 21B is formed on the left front side below the cab main body 22 described later, and a bottom portion 21C of the accommodation portion 21B is attached with a shock absorber 32 described later. A pair of screw seats 21E to which a bracket 21D and a leaf spring 28, which will be described later, are attached are provided one by one on the left and right sides.

The upper surface portion 21 of the revolving frame 21
As shown in FIGS. 2 and 3, a pair of working device brackets 21F, 21F is provided on the front side of A, and each bracket 21F supports the boom 17A and each boom cylinder 17D with high rigidity. ing.

Reference numeral 22 denotes a driver's cab body disposed on the front left side of the revolving frame 21, and the driver's cab body 22 is constructed in substantially the same manner as the driver's cab body 8 of the driver's cab 6 described in the prior art, and has a ceiling. It has a part 22A, a front part 22B, a rear part 22C and left and right side parts 22D, 22D. here,
At the lower ends of the front surface portion 22B, the rear surface portion 22C, and the side surface portions 22D, the floor plate brackets 22E, 22E,
Is provided, and a door 23 is provided on the left side surface portion 22D of the cab body 22. And the driver's cab body 2
2-4, laminated seismic isolation rubbers 39 and 40, which will be described later, are attached to the rear surface portion 22C and the right side surface portion 22D near the corner 22F on the rear right side.

Reference numeral 24 denotes a floor plate which constitutes a part of the cab body 22, and the floor plate 24 has a double structure,
Bottom plate 25 as an upper floor plate part that closes the lower surface side of 2
And a support plate 26 as a lower floor plate portion which is separated from the bottom plate 25 and is arranged between the bottom plate 25 and the upper surface portion 21A of the revolving frame 21.

Here, the bottom plate 25 has a cylindrical shape with a lid to accommodate each of the vibration-proof rubbers 33, which will be described later, at four corners inside the portion where the bottom plate 25 is fixed to the floor plate bracket 22E of the operator cab body 22. The housing portions 25A, 25A ... Are provided so as to project upward. Further, on the upper surface of the bottom plate 25, mounting brackets 25B (only the left side is shown) are located on the front side between the front and rear accommodating portions 25A, 25A so as to be spaced apart from each other in the left and right directions and project upward. Each shock absorber 32 described below is attached to the bracket 25B.

On the other hand, the support plate 26 is formed with a predetermined plate thickness so as to support the entire cab main body 22 on the swivel frame 21, and the support plate 26 has each accommodating portion 2 of the bottom plate 25.
Spring mounting brackets 26A and 26B are provided so as to project downward from the lower surface side of the portion facing 5A. In addition, the shock absorber 32 is provided on the support plate 26 at a position spaced apart in the left-right direction and facing the mounting bracket 25B of the bottom plate 25.
An insertion hole 26C through which the is inserted is formed.

Reference numeral 27 denotes a lower cushion support provided between the floor plate 24 and the swivel frame 21, and the lower cushion support 27 includes a leaf spring 28 formed by stacking a plurality of spring plates. , And a shock absorber 32 described later.

Here, the leaf spring 28 is the support plate 2
Two leaf springs 28 are provided apart from each other on the right and left sides of 6 and extending in the front-rear direction (only one is shown). Each leaf spring 28 is a main leaf 28A as a spring plate having front and rear ends as mounting portions.
And auxiliary leaves 28B, 28C, 28D as, for example, four spring plates, which are provided on the lower side of the main leaf 28A so as to be successively shortened in length, and the main leaf 2
The main leaf 28A and each auxiliary leaf 2 on both end sides of 8A
8B to 28D and a clip band 28E provided so as not to be laterally displaced, and the leaf spring 28 has a center bolt in a bolt insertion hole (not shown) formed in the vertical direction from the center of the main leaf 28A to the auxiliary leaf 28D at the lowermost stage. It is firmly fixed by inserting 29 into the screw seat 21E and tightening it with a nut 30. Further, in each leaf spring 28, the front mounting portion of the main leaf 28A is pin-coupled to the spring mounting bracket 26A of the support plate 26 via a rubber bush or the like (not shown), and the rear mounting portion of the main leaf 28A is connected via the shackle 31. Support plate 2
6 is pin-connected to the spring mounting bracket 26B. The shackle 31 absorbs a change in length that occurs when the leaf spring 28 bends.

Each leaf spring 28 has a main leaf 28A and auxiliary leaves 28B, 28C, 28D when the cab body 22 vibrates in the vertical direction (Z-axis direction).
This vibration is absorbed and quickly damped by the friction generated between them. Further, the spring constant of each leaf spring 28 can be appropriately changed by increasing or decreasing the number of auxiliary leaves 28B to 28D and the like. In particular, in the present embodiment, the spring constant of each leaf spring 28 is set to be smaller than the spring constant of the lower cushion support 11 described in the conventional art by providing the laminated seismic isolation rubbers 39 and 40, which will be described later, in the cab body 22. Can also be set smaller.

Reference numeral 32 denotes a shock absorber mounted between the mounting bracket 21D of the revolving frame 21 and the mounting bracket 25B of the bottom plate 25. The shock absorber 32 is elastically supported on the revolving frame 21 by the leaf spring 28. The operator's cab main body 22 expands and contracts as it vibrates in the vertical direction.
The vibration of the vertical direction of 2 is buffered.

33, 33 ... Are bottom plates 2 which constitute the floor plate 24.
5 shows an anti-vibration rubber (only two are shown) as an elastic member provided between the accommodating portion 25A of 5 and the supporting plate 26, and each anti-vibrating rubber 33 extends from the accommodating portion 25A of the bottom plate 25 to the supporting plate 26 side. And elastically supports between the bottom plate 25 and the support plate 26. The anti-vibration rubbers 33 are used as the main leaf 28A and the auxiliary leaf 2 of the leaf spring 28.
The squeak noise generated by the friction between 8B and 28D and the vibration of a high frequency that cannot be absorbed by the leaf spring 28 are absorbed.

Numerals 34 and 35 denote struts as vibration restricting members fixed to the working device bracket portion 21F, which is a high-rigidity portion of the revolving frame 21, through bolts (not shown) or the like. 2 to 4, it is formed of a highly rigid metal plate material having a U-shaped cross section, and extends upward from the revolving frame 21 with a predetermined height dimension. The struts 34, 35 are located in the vicinity of the corner 22F on the rear right side of the cab main body 22, and the struts 34 face the rear surface 22C of the cab main body 22 at a predetermined interval.
The support column 35 faces the right side surface portion 22D at a predetermined interval.

Here, as shown in FIG. 4, the column 34 has a predetermined width dimension in the left-right direction of the revolving frame 21, and a flat plate portion 34A extending in the vertical direction by a predetermined length, and the left side of the flat plate portion 34A. , And includes reinforcing plate portions 34B and 34C which are formed by bending both right end sides into a substantially L shape and extend to the rear of the cab body 22, and the lower end side of the reinforcing plate portion 34C is a working device bracket portion. It is fixed to the left side surface of 21F. Further, a bolt insertion hole 34D is formed at a predetermined height position in the flat plate portion 34A of the support column 34, and a mounting bolt 3 for a laminated seismic isolation rubber 39 described later is provided in the bolt insertion hole 34D.
9A is inserted.

On the other hand, the support column 35 has a predetermined width dimension in the front-rear direction of the revolving frame 21, and a flat plate portion 35A extending vertically with a predetermined length, and the front and rear end sides of the flat plate portion 35A are substantially formed. Formed by bending into an L shape,
Reinforcing plate portions 35B, 35 extending to the right of the cab body 22
C, and the lower end side of the flat plate portion 35A is fixed to the right side surface of the working device bracket portion 21F via a flat plate-shaped spacer 36. Then, the flat plate portion 35A of the support column 35
Has a bolt insertion hole 35D at a predetermined height position,
A mounting bolt 40A for a laminated seismic isolation rubber 40, which will be described later, is inserted through the bolt insertion hole 35D.

Reference numerals 37 and 38 denote corners 22 of the cab body 22.
A screw seat located near F and fixed to the rear surface portion 22C and the side surface portion 22D by means of welding or the like is shown.
7 and 38 are formed in a columnar shape or a prismatic shape having a predetermined wall thickness, and bottomed screw holes 37A and 38A are formed in the center thereof. The screw seats 37 and 38 are arranged at a predetermined height position between the rear surface portion 22C and the side surface portion 22D, and the screw holes 37A and 38A are the bolt insertion holes 3 of the columns 34 and 35.
It faces 4D and 35D.

Further, 39 and 40 denote laminated seismic isolation rubbers as elastic cushioning members provided between the columns 34 and 35 and the screw seats 37 and 38. The laminated seismic isolation rubbers 39 and 40 are mounting bolts 39A. , 39B, and between the mounting bolts 40A, 40B, rubber plates 39C, 39C ,.
C, 40C, ... and steel plates 39D, 39 as metal plates
, 40D, 40D, ... are alternately laminated, and have a large spring constant for tensile and compressive loads in the plate thickness direction, and a small spring for shearing loads. Has a constant.

Here, in the laminated seismic isolation rubbers 39 and 40, the mounting bolts 39A and 40A are fixed to the columns 34 and 35 by the nuts 41 and 42, respectively, and the mounting bolts 39B and 40B.
Is fixed to the screw holes 37A and 38A of the screw seats 37 and 38, and is disposed between the columns 34 and 35 and the screw seats 37 and 38 in a state where an initial load is applied to the rubber plates 39C and 40C. . The laminated seismic isolation rubber 39 is used for the driver's cab body 22.
Vibrates in the front-back direction (Y-axis direction) with a large spring constant, and the laminated seismic isolation rubber 40 buffers vibration of the cab body 22 in the left-right direction (X-axis direction) with a large spring constant. Further, the laminated seismic isolation rubbers 39 and 40 buffer the vibration of the cab main body 22 in the vertical direction (Z-axis direction) together with the lower cushioning supports 27 and the vibration-proof rubber 33 with a relatively small spring constant. .

The hydraulic excavator according to the present embodiment has the above-mentioned construction, and its basic operation is not different from that of the prior art.

In the present embodiment, however, the floor plate 24 of the operator cab body 22 is composed of the bottom plate 25 and the support plate 26 with the anti-vibration rubbers 33, 33 ,.
1 and the support plate 26, lower cushioning supports 27 including leaf springs 28 and shock absorbers 32 are provided on both left and right sides, while the revolving frame 21 is located near the corners 22F of the cab body 22. The columns 34 and 35, and the columns 34 and 35 and the rear surface portion 22 of the cab body 22.
The laminated seismic isolation rubbers 39 and 40 that buffer horizontal vibrations with a large spring constant and buffer vertical vibrations with a small spring constant are provided between C and the side surface portion 22D. Play.

That is, the swivel frame 21 and the cab body 22
By setting the spring constant of each leaf spring 28 provided between the cab main body 22 and the floor plate 24 to be small and supporting the cab main body 22 via the laminated seismic isolation rubbers 39 and 40, the natural frequency f of the cab main body 22 is set. It can be made small, and the vibration transmissibility τ is kept small for the vertical vibration transmitted from the revolving frame 21 to the cab main body 22 when working or running the hydraulic excavator, and the vertical vibration of the cab 6 is effectively damped. it can.

In particular, the leaf spring 28 is provided for the main leaf 28A when the cab body 22 vibrates in the vertical direction.
Large vibrations can be absorbed and quickly damped by the friction generated between the auxiliary leaves 28B to 28D, and the anti-vibration rubbers 33 interposed between the support plate 26 and the bottom plate 25 are the main parts of the leaf spring 28. Leaf 28
It is possible to absorb and damp a squeak sound generated by friction between the A and the auxiliary leaves 28B to 28D and a high frequency vibration that cannot be absorbed by the leaf spring 28 and the shock absorber 32.

Further, from the swing frame 21 to the cab main body 2
When the vibration in the front-rear direction is transmitted to 2, the vibration can be regulated by the laminated seismic isolation rubber 39 between the column 34 and the screw seat 37 so as to have a small spring amplitude so that the amplitude of the leaf spring 28 is reduced. Even if the spring constant is set to a small value, it is possible to prevent the leaf springs 28 from vibrating in a wavy manner by tilting in the front-rear direction, and effectively suppressing large vibrations (pitching) in the operator's cab body 22 in the front-rear direction. be able to. And the turning frame 21
When a horizontal vibration is transmitted from the driver's cab body 22 to the driver's cab body 22, this vibration can be regulated by the laminated seismic isolation rubber 40 between the column 35 and the screw seat 38 with a large spring constant to reduce the amplitude. It is possible to effectively suppress the large vibration (rolling) of 22 in the left-right direction.

Therefore, in this embodiment, it is possible to effectively prevent the driver's cab main body 22 from pitching in the front-rear direction or rolling in the left-right direction, and the driver's cab main body 22 is boom cylinder 17D (see FIG. 4) or the like. In addition to solving the problem of collision with surrounding members of the vehicle, the natural frequency of the driver's cab 6 can be reduced to reliably reduce the vertical vibration transmitted to the driver's cab main body 22, thereby significantly improving the riding comfort of the vehicle. Various effects such as being possible can be achieved.

Next, FIGS. 5 to 8 show a second embodiment of the present invention. In this embodiment, the same components as those of the first embodiment are designated by the same reference numerals, and the description thereof will be omitted. However, the feature of the present embodiment is that the corner portion 2 of the operator cab body 22 is attached to the working device bracket portion 21F of the revolving frame 21.
The screw seat 5 provided on the corner portion 22F of the operator cab body 22 is provided with a support column 51 as a vibration restrictor so as to face the 2F.
There is a laminated seismic isolation rubber 53 as an elastic buffer between the column 2 and the column 51.

Here, the support column 51 is formed in substantially the same manner as the support column 34 described in the first embodiment and has the flat plate portion 51A, the reinforcing plate portions 51B and 51C and the bolt insertion hole 51D. The flat plate portion 51A of the support column 51 has its lower end side fixed to the working device bracket portion 21F in a state of being inclined at an angle of, for example, 45 degrees. Also, the screw seat 52
Is fixed to a corner portion 22F of the operator cab body 22 so as to face the flat plate portion 51A of the support column 51 at a predetermined interval. From the rear surface portion 22C and the right side surface portion 22D of the operator cab body 22, as shown in FIG. It projects with an inclination of 45 degrees. Then, a mounting bolt 53B described later is attached to the screw seat 52.
The screw hole 52A into which the is screwed is the bolt insertion hole 5 of the column 51.
It is formed so as to face 1D.

In addition, the laminated seismic isolation rubber 53 is similar to the laminated seismic isolation rubber 39 (40) described in the first embodiment, and the rubber plates 53C and 5 are provided between the mounting bolts 53A and 53B, respectively.
3C, ... And steel plates 53D, 53D, ... are laminated, and the mounting bolt 53A is fixed to the flat plate portion 51A of the support column 51 with a nut 54, and the mounting bolt 53B.
Is screwed into a screw hole 52A of the screw seat 52. The laminated seismic isolation rubber 53 is mounted between the corner portion 22F on the rear right side of the cab main body 22 and the support column 51 at an angle of, for example, 45 degrees, so that the cab main body 22
Vibrates (pitches) in the front-back direction (Y-axis direction),
Vibration (rolling) in the horizontal direction (X-axis direction) is buffered with a large spring constant, and vibration in the vertical direction is buffered with a small spring constant.

Thus, in this embodiment having the above-described structure, it is possible to obtain substantially the same effect as that of the first embodiment, but in this embodiment, in particular, a single laminated seismic isolation rubber 53 is used. Both front-rear and left-right vibrations of the cab main body 22 can be restricted to be small, and the number of parts such as the support column 51, the screw seat 52, and the laminated seismic isolation rubber 53 can be reduced.

In each of the above embodiments, the cab body 22
The case where the anti-vibration rubber 33, 33, ... Is provided as an elastic buffer between the bottom plate 25 and the support plate 26 that form the floor plate 24 has been described as an example, but the present invention is not limited to this. For example, the lower cushion support 11 made of the vibration-proof rubber 12 or the like shown in FIG. 11 described in the prior art may be used, or the same as the laminated seismic isolation rubber 39 (40) may be used.

Further, in each of the above-mentioned embodiments, the hydraulic excavator has been described as an example, but the present invention is not limited to this, and is also applied to a working machine such as a wheel type hydraulic excavator having a cab or a hydraulic crane. it can.

[0061]

As described in detail above, according to the present invention, each lower cushioning support is composed of a leaf spring and a shock absorber, and the main body frame is provided in the vicinity of the rear corners of the cab main body. Positioned and provided with a vibration regulator,
Between the vibration regulator and the driver's cab main body, there is an elastic buffer that buffers horizontal vibration of the driver's cab main body with a large spring constant and buffers vertical vibration with a small spring constant. Since it is provided, the vertical vibration of the driver's cab main body can be quickly attenuated by the leaf spring and the shock absorber that constitute the lower cushioning support. Especially, if the spring constant of the leaf spring is set low, the driver's natural vibration The number can be reduced, and the vibration transmitted to the cab can be effectively reduced.

Further, by constructing the elastic cushioning member with laminated seismic isolation rubber or the like, it is possible to prevent the operator's cab body from pitching in the front-rear direction or rolling in the left-right direction, and it is possible to prevent collision with surrounding members. In addition to being surely preventable,
The natural frequency of the driver's cab can be reduced to effectively dampen the vertical vibrations and improve the ride comfort of the vehicle.

If elastic cushioning members are provided between the upper and lower floor plate portions of the operator's cab body, the elastic member can absorb vibrations at high frequencies that cannot be absorbed by the lower cushioning support. The driver's cab with improved ride comfort can be provided.

[Brief description of drawings]

FIG. 1 is a partially cutaway external view showing a cab body, a swivel frame, and the like according to a first embodiment of the present invention.

FIG. 2 is a perspective view showing a driver's cab body and the like provided on a swing frame.

FIG. 3 is a plan view of FIG.

FIG. 4 is an enlarged cross-sectional view of a pillar, laminated seismic isolation rubber and the like shown in FIG.

FIG. 5 is an external view similar to FIG. 1 showing a second embodiment.

FIG. 6 is a perspective view similar to FIG. 2 showing a second embodiment.

FIG. 7 is a plan view of FIG.

FIG. 8 is an enlarged cross-sectional view of the column, laminated seismic isolation rubber and the like shown in FIG.

FIG. 9 is an overall view showing a hydraulic excavator according to a conventional technique.

FIG. 10 is a partially broken external view showing an enlarged view of the swivel frame, the cab body, and the like in FIG.

FIG. 11 is an enlarged cross-sectional view of the lower cushioning support and the like shown in FIG.

FIG. 12 is an explanatory diagram for analyzing vibration in a cab.

FIG. 13 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]

 21 swivel frame (main body frame) 22 driver's cab main body 22F corner portion 24 floor plate 25 bottom plate (upper floor plate portion) 26 support plate (lower floor plate portion) 27 lower buffer support 28 leaf spring 28A main leaf 28B, 28C, 28D Auxiliary leaf 28E Clip band 29 Center bolt 31 Shackle 33 Anti-vibration rubber (elastic member) 34, 35 Strut (vibration restrictor) 37, 38 Screw seat 39, 40, 53 Laminated seismic isolation rubber (elastic cushion) 39C, 40C , 53C rubber plate 39D, 40D, 53D steel plate (metal plate)

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Zenji Kaneko 650 Jinrachicho, Tsuchiura City, Ibaraki Prefecture Tsuchiura Plant, Hitachi Construction Machinery Co., Ltd. Machinery Company Tsuchiura Factory

Claims (3)

[Claims] 1. A main body frame of a working machine, a box-shaped driver's cab main body provided on the main body frame and provided with a floor plate on the lower surface side, and between the floor plate of the operator's cab main body and the main body frame. In a driver's cab of a working machine, each of which is provided with a plurality of lower cushioning supports that dampen transmission of vibrations from the body frame to the operator's cab body, each of the lower cushioning supports includes a leaf spring and a shock absorber. And a vibration restricting body is provided on the main body frame near the rear side corner of the cab main body, and the cab main body is horizontal between the vibration restricting body and the cab main body. An operator's cab of a working machine, which is provided with an elastic cushioning body that buffers vibration in a vertical direction with a large spring constant and buffers vibration in a vertical direction with a small spring constant. 2. The operator's cab of a working machine according to claim 1, wherein the elastic buffer body is made of laminated seismic isolation rubber formed by laminating a rubber plate and a metal plate each having a predetermined plate thickness. 3. The floor plate of the cab body is composed of upper and lower floor plate parts having a double structure, and the cab body is elastically arranged on the lower floor plate part between the floor plate parts. The operator's cab of the working machine according to claim 1 or 2, further comprising an elastic member that supports and cushions vibration of a frequency higher than that of the leaf spring.