JPH07166581A - Work machine with driver's cab - Google Patents

Abstract

PURPOSE:To improve the riding comfortableness by restricting the longitudinal and lateral vibrations of a driver's cab due to the vibration from a frame, and reducing the natural frequency of the driver's cab. CONSTITUTION:A swivel frame 21 and a driver's cab main body 22 are rotatably connected by a link mechanism 32 on the front side and rotatably connected via a hydraulic cylinder 35 on the rear side. A selector valve switching the feed/discharge position and the stop position of the pressure oil is provided in the middle of a pipe connecting the hydraulic cylinder 35 to a hydraulic pump and a tank. When the selector valve is set to the feed/discharge position, a piston is fixed to the tube 36 of the hydraulic cylinder 35, and a parallel link is formed with the hydraulic cylinder 35 and the link mechanism 32. When the selector valve is set to the stop position, the expanding/shrinking action of the rod 38 of the hydraulic cylinder 35 is allowed, and it elastically supports the driver's cab main body 22 on the swivel frame 21 together with lower cushioning supporters 25.

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 located on the rear side of the machine room 5. The counterweight 7 balances the entire upper revolving structure 3 with a working device 17 described later. It is designed to let you.

Reference numeral 8 denotes a driver's cab main body which is disposed on the revolving frame 4 and constitutes a main body of the driver's cab 6. The operator cab main body 8 is formed by pressing a thin steel plate as shown in FIG. By welding by welding, a rectangular ceiling portion 8A extending in the front-rear direction and a rectangular front portion 8 extending vertically.
B, a vertically long rectangular rear surface portion 8C which is a surface substantially vertical to the revolving frame 4, and substantially rectangular left and right side surfaces provided 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 including parts 8D, 8D (only one is shown). 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 provided on the lower surface side of the driver's cab body 8 via a floor plate bracket 8E. Installed.

Reference numerals 11, 11, ... Show lower cushion supports that elastically support the cab body 8 on the swivel frame 4, and each of the lower cushion supports 11 will be described later as shown in FIGS. 14 and 15. Anti-vibration rubber 12, spacer 13 and each stopper 1
It is composed of 4 etc. And, each of the lower cushioning supports 11 is spaced apart between the floor plate 10 of the cab body 8 and the revolving frame 4 in the front, rear, left, and right, for a total of four (only two are shown).
It is provided so as to damp transmission of vibrations from the swivel frame 4 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.

Numeral 13 is a spacer made of a metal cylinder having a bolt insertion hole 13A in the axial direction. The spacer 13 has an intermediate portion in the longitudinal direction loosely fitted in the mounting hole 4B of the revolving frame 4, and the upper and lower parts are formed. Both end sides are fitted into the insertion holes 12A of the anti-vibration rubbers 12. 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 pressing a metal plate or the like, and each stopper 14 has a disk-like shape having a diameter larger than that of the vibration-proof rubber 12 as shown in FIG. A bottom portion 14B formed with a bolt insertion hole 14A in the center and a cylindrical portion 14C axially extending from the outer peripheral side of the bottom portion 14B and having a length dimension shorter than that of the vibration isolating rubber 12. 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, ...
5 is inserted into each bolt insertion hole 8F of the floor plate bracket 8E from the inside of the operator's cab main body 8, and the bolt insertion hole 13A of each spacer 13, each bolt insertion hole 10A of the floor plate 10, and the upper surface portion 4A of the swivel frame 4 are provided. The operator cab main body 8 is positioned on the revolving frame 4 by extending the inside of each mounting hole 4B and screwing and tightening the nut 16 from the lower side of the lower buffer support 11, that is, the lower side of the bottom portion 14B of the stopper 14. ing.

Reference numeral 17 denotes a working device provided in the front portion of the upper swing body 3, and the working device 17 can be lifted and lowered on a highly rigid bracket portion (not shown) forming a part of the swing frame 4. A boom 17A provided, an arm 17B provided at the tip of the boom 17A so as to be able to move up and down, and the arm 1
7B and a bucket 17C of a backhoe type rotatably provided at the tip of 7B. These boom 17A, arm 17B, and bucket 17C are operated by a boom cylinder 17D, an arm cylinder 17E, and a bucket cylinder 17F, respectively. ing. The working device 17 is used for boom cylinder 17 during excavation work such as earth and sand.
While the boom 17A and the arm 17B are raised and lowered by the D and arm cylinders 17E, the bucket 17C is rotated by the bucket cylinder 17F, and the earth and sand are excavated by the bucket 17C.

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. 15, each lower buffer support 11 has an opening 14D of each stopper 14 with respect to the upper surface 4A of the revolving frame 4 with a gap S of, for example, about 2 to 3 mm.
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 operator's cab 6, but in reality, the following problems based on natural frequencies occur.

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 vertical natural frequency f of the driver's cab 6 is

[0016]

[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. 16, and the amplitude a _{0 is applied} from the lower side.
When the forced vibration a ₀ cos ωt of is applied in the vertical direction, and the amplitude of the vibration transmitted to the cab 6 is a, the vibration transmissibility τ is

[0018]

[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 =
The vibration increases due to resonance before and after 1, and the frequency ratio η increases. Especially, if it is √2 or more, the vibration transmissibility τ
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 kgf / cm, the natural frequency f of the operator's cab 6 is about 20 to 45 Hz from the above formula 1.

However, since the vibration of the hydraulic excavator during operation, especially during traveling, includes a large amount of vibration of 5 to 9 Hz, if the natural frequency f of the cab 6 is within the above range, the frequency ratio η
Is 0.11 to 0.45, and the vibration transmissibility τ is 1 or more, so that the vibration damping effect cannot be obtained and the riding comfort is deteriorated.

Therefore, when the hydraulic excavator is running, 5 to 9H
For the vibration of z, in order to set the vibration transmissibility τ to 1 or less, it is necessary to reduce the spring constant k of each lower cushioning support 11 so that the natural frequency f of the cab 6 is 3.5 Hz or less. There is. However, in such a case, although vibration in the vertical direction can be attenuated, pitching in which the cab 6 vibrates in the front-rear direction on the swivel frame 4 and rolling in which the cab 6 vibrates in the left-right direction become large, which deteriorates the riding comfort. Will end up.

When the pitching or rolling becomes large, the cab main body 8 is moved to the boom cylinder 17
Since it may collide with a peripheral member such as D and cause a damage accident, as shown in FIG. 15, the gap S between the opening 14D of each stopper 14 and the upper surface 4A of the revolving frame 4 is, for example, 2 to
When the driver's cab body 8 vibrates beyond the gap S, the openings 14D of the stoppers 14 collide with the upper surface 4A of the swivel frame 4 and the swivel frame 4 is set to about 3 mm.
The vibration from the vehicle is directly transmitted to the driver's cab body 8, and the ride 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 can effectively prevent the driver's cab body from vibrating to the front, rear, left, and right to cause pitching and rolling. At the same time, it is an object of the present invention to provide a working machine with a driver's cab that can effectively damp vertical vibrations and improve riding comfort.

[0025]

In order to solve the above-mentioned problems, the invention according to claim 1 is a box shape in which a frame of a work machine main body and a floor plate provided on the lower surface of the frame are provided on the frame. Work with a driver's cab comprising a driver's cab main body and a plurality of lower cushion supports that are provided between the floor plate and the frame of the driver's cab main body and buffer the vibration from the frame transmitted to the driver's cab main body In the machine, between the cab body and the frame, a link mechanism extending in the front-rear direction and rotatably connected at both ends to the cab body and the frame, and from the link mechanism to the cab body A hydraulic cylinder, which is separated in the front-rear direction and is rotatably connected to the cab main body and the frame at both ends, and constitutes a parallel link together with the link mechanism, is provided with a tube and a tube. A piston that defines the inside of the valve into two oil chambers, a rod that has one end side fixed to the piston and the other end side that protrudes outside the tube, and pressure oil that flows between the oil chambers when the rod expands and contracts. A damping force generating mechanism for generating a damping force, and a pressure oil supply / discharge position and a stop position are provided in the middle of a pipeline connecting each oil chamber of the hydraulic cylinder to a hydraulic pressure source and a tank. A switching valve that can be switched is provided, and the switching valve supplies and discharges the pressure oil from the hydraulic pressure source to and from each oil chamber of the hydraulic cylinder at the supply / discharge position, and the respective hydraulic chambers of the hydraulic cylinder to the hydraulic source at the stop position. It employs a configuration that shuts off and communicates with the tank.

Further, in the invention according to claim 2, an operating state detecting means for detecting an operating state of the working machine is provided in the working machine body, and the operating state detecting means is provided between the operating state detecting means and the switching valve. There is provided control means for controlling switching of the switching valve based on a signal from the means.

Further, in the invention according to claim 3, the running / stopping state detector for detecting the running / stopping state of the working machine from the operating position of the running lever provided in the cab body in the operating state detecting means. And a work / stop state detector that detects the work / stop state of the work machine from the operating position of the work lever provided in the operator's cab body.

Further, in the invention according to claim 4, the operating state detecting means is provided on the frame of the driver's cab body, and is constituted by inclination detecting means for detecting the inclination of the frame.

On the other hand, in the invention according to claim 5, a pressure from the hydraulic source is applied to the hydraulic cylinder so that the piston is automatically returned to the intermediate position in the tube when the switching valve is at the supply / discharge position. A piston position control valve that supplies and discharges oil to and from each oil chamber is provided.

Further, in the invention according to claim 6, the valve casing of the piston position control valve according to claim 5 is constituted by the tube of the hydraulic cylinder, and the spool integrally forms with the piston.

In the invention according to claim 7, the link mechanism includes a pair of link members extending in the front-rear direction between the floor plate of the cab body and the frame and spaced apart in the left-right direction, and the link members. A linking member that links the link members in the left-right direction so that the rotations of the link members are synchronized,
Both ends of each of the link members in the front-rear direction are rotatably connected to the floor plate and the frame of the cab body.

Further, in the invention according to claim 8, the hydraulic cylinder is arranged between the frame of the working machine main body and the floor plate of the operator's cab main body.

On the other hand, in the invention according to claim 9, the hydraulic cylinder is disposed between the support column standing upright from the frame of the working machine body and the rear surface portion of the cab body.

According to the tenth aspect of the present invention, each of the lower buffer supports is composed of a coil spring and an oil damper that buffer the vibration of the cab body with a relatively small spring constant.

[0035]

With the above construction, in the invention according to claims 1 to 4, the changeover valve is automatically changed over according to the vibration state or the sloped state of the terrain when the working machine is traveling or working, and the changeover is performed. When the valve is switched to the supply / discharge position, the piston is fixed in the tube of the hydraulic cylinder, and the hydraulic cylinder and the link mechanism form a parallel link, so that the parallel link is generated when the cab body vibrates on the frame. When the driver's cab vibrates in the horizontal direction, for example, the vibration in the front-back direction is converted into vertical vibration, horizontal vibration can be restricted to a small level, and the driver's cab body vibrates in the front-back direction. (Pitching) can be reliably reduced. On the other hand, when the switching valve is switched to the stop position, the rod of the hydraulic cylinder can be expanded and contracted, and it is possible to allow the hydraulic cylinder and the link mechanism to perform different rotational movements from each other. It is possible to elastically support the frame via the lower cushion supports, and softly absorb vibrations from the frame by the lower cushion supports and the hydraulic cylinders.

According to the invention of claim 5, the hydraulic cylinder can be fixed to a fixed length simply by switching the switching valve to the supply / discharge position, and the hydraulic cylinder and the link mechanism quickly form a parallel link. be able to.

According to the invention described in claim 6,
It is possible to reduce the number of components and form the entire device in a small size.

Further, according to the invention of claim 7,
For example, even if a force that oscillates the driver's cab body in the left-right direction acts on the frame, the link members that connect the link members can rotate the link members in synchronization with each other. It is possible to regulate rolling of the chamber body in the left-right direction.

According to the eighth aspect of the present invention, the damping force variable hydraulic cylinder is disposed between the frame of the working machine body and the floor plate of the operator's cab body, whereby the hydraulic cylinder is provided. Can be compactly accommodated.

According to the invention described in claim 9, the damping force variable hydraulic cylinder is disposed between the support column standing upright from the frame of the working machine body and the rear surface portion of the cab body. As a result, the distance between the link mechanism and the hydraulic cylinder can be increased, and the operator cab main body can be stably supported against vibration of large amplitude.

According to the tenth aspect of the present invention, since each of the lower cushioning supports is composed of the coil spring and the oil damper, the vertical vibration of the cab main body can be supported with a small spring constant, and the operation can be performed. By reducing the natural frequency of the entire room, it is possible to satisfactorily dampen the vertical vibration transmitted to the operator's cab main body especially when the working machine is traveling.

[0042]

Embodiments of the present invention will be described below with reference to FIGS. In addition, in the embodiment, 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 10 show a first embodiment of the present invention.

In the figure, reference numeral 21 denotes a swivel frame which constitutes a frame of the upper swivel body 3, and the swivel frame 21 is substantially the same as the swivel frame 4 described in the prior art, and the swivel device 2 is provided.
The portion on the center side that is attached to the is formed as a thick high-rigidity portion 21A having high rigidity (FIGS. 1 and 2).
reference). The swivel frame 21 has a high rigidity portion 21.
A bearing portion 21B is provided on the left side of the front portion of A for supporting a driver's cab body 22 described below from below. The bearing portion 21B is separated from the front and the rear to extend in the left-right direction and has a substantially U-shaped cross section. Two beam portions 21B1 and 21B2 having a shape, and each beam portion 21
Side frame 2 that connects the left ends of B1 and 21B2 in the front-rear direction
1B3 and a front frame portion 21B4 provided in front of the beam portion 21B1 and the like.

Further, brackets 21C, 21C are integrally formed on the frame 21 on the front side of the high-rigidity part 21A and on the right side of the support part 21B, and the booms 17A of the working device 17 and the boom cylinders are formed on the brackets 21C. 1
7D is attached by pin connection.

Reference numeral 22 denotes a driver's cab main body provided on the swivel frame 21, and the driver's cab main body 22 is substantially the same as the driver's cab main body 8 of the driver's cab 6 described in the prior art.
Front part 22B, rear part 22C and left and right side parts 22
D, 22D, and a door 23 is provided on the left side surface portion 22D. Further, a floor plate 24 forming a part of the cab main body 22 is provided on the lower surface side of the cab main body 22, and the floor plate 24 is mounted on the high-rigidity portion 21A and the support portion 21B of the revolving frame 21 and the lower portions described later. It is configured to support the entire cab 6 via the buffer support 25.

Reference numerals 25, 25, ... Show lower buffer supports provided between the swivel frame 21 and the floor plate 24 of the cab body 22, and each of the lower buffer supports 25 is shown in FIGS. As described above, between the support portion 21B and the high-rigidity portion 21A of the swivel frame 21 and the floor plate 24 of the cab body 22,
It is composed of an oil damper 26, which is provided separately from each other on the left and right sides, and is composed of hydraulic shock absorbers, and a coil spring 27 that constantly urges the oil damper 26 in the extension direction. It is formed with a relatively small spring constant.

Among the lower buffer supports 25,
The lower cushion support 25 located on the right side of the rear portion in FIG. 2 is disposed on the high-rigidity portion 21A of the revolving frame 21, and the other lower cushion supports 25 are disposed on the support 21B.

Reference numerals 28 and 28 denote link-mounting brackets which are erected downward from the lower side surface of the floor plate 24. Each bracket 28 is composed of two plates facing each other in parallel as shown in FIG. Are separated from each other on the left and right sides and fixed by means such as welding, and project toward the revolving frame 21 side with a predetermined height.

Reference numeral 29 is another bracket provided on the floor plate 24. The bracket 29 is composed of two plates similar to the bracket 28, and the bracket 29 is equidistantly spaced from the left and right brackets 28 to the rear side. Is provided.

Reference numerals 30 and 30 denote brackets for mounting links provided on the swivel frame 21. Each bracket 30 is composed of two plates, and is formed so as to project forward from the beam portion 21B1 so as to face the bracket 28. ing.

Reference numeral 31 denotes a shock absorber mounting bracket provided on the beam portion 21B2. Each of the brackets 31 is on the rear side of the cab main body 22 with respect to the bracket 29 so that the beam portion is opposed to the bracket 29. It is provided so as to project forward from 21B2.

Reference numeral 32 denotes the swivel frame 21 and the cab body 22.
Shows a link mechanism that is rotatably connected to the floor plate 24 of the vehicle through brackets 28 and 30.
2 is a pair of link members 33, 33 extending in the front-rear direction between the floor plate 24 of the cab body 22 and the swivel frame 21, and fixed to the center of each of the link members 33, 33 spaced apart left and right. It is formed in a substantially H shape with a flat plate-like connecting member 34 that connects the link members 33 in the left-right direction. Here, the connecting member 34 imparts an anti-twisting force to each link member 33 when the cab main body 22 tries to vibrate in the left-right direction on the revolving frame 21, so that each link member 33 rotates independently. Is regulated to prevent the cab main body 22 from rolling in the left-right direction and vibrating.

Reference numeral 35 denotes a hydraulic cylinder rotatably provided between the mounting brackets 29 and 31 by connecting both ends with a pin. The hydraulic cylinder 35 includes a tube 36, a piston 37, a rod 38, etc., which will be described later. It is roughly composed.

Reference numeral 36 denotes a bottomed tubular tube which constitutes the hydraulic cylinder 35. The tube 36 is provided with a bottom side port 36A, an intermediate port 36B and a rod side port 36C which are axially separated from each other. Each port 36A
To 36C, a supply side conduit 43A and a return side conduit 4 which will be described later.
3B and the branch conduit 43C are switchably connected.

Reference numeral 37 denotes a piston slidably fitted in the tube 36 and defining the inside of the tube 36 into a bottom side oil chamber A and a rod side oil chamber B. The piston 37 is provided outside the tube 36. A protruding rod 38 is fixedly provided. As shown in FIG. 4, annular oil grooves 37A and 37B are formed on the outer peripheral surface of the piston 37 so as to be axially separated from each other, and the outer peripheral surface between the oil grooves 37A and 37B is land 37.
C, the outer peripheral surface on the bottom side of the oil groove 37A is the land 37
D, the outer peripheral surface on the rod side of the oil groove 37B is a land 37E.
Has become.

Reference numerals 39 and 40 respectively denote oil passages formed in the piston 37. The oil passages 39 are the oil chamber A and the oil groove 3 respectively.
The oil passage 40 communicates between the oil chamber B and the oil groove 37A. Here, the oil passage 39 is provided with a throttle portion 39A as a damping force generating mechanism, and the oil passage 40 is provided with a throttle portion 40A as a damping force generating mechanism.

Reference numeral 41 denotes a hydraulic pump as a hydraulic source for supplying and discharging pressurized oil to and from the hydraulic cylinder 35, and 42 denotes a tank for storing hydraulic oil. The hydraulic pump 41 and the tank 42 are connected to the hydraulic cylinder 35 by a conduit 43 described later. It is connected to the.

43 is the tube 3 of the hydraulic cylinder 35.
6 is a pipe line connecting the hydraulic pump 41 and the tank 42, and the pipe line 43 is a tank 42 and an electromagnetic switching valve 4 described later.
4 is connected to the pump side port, and the supply side pipeline 43A is provided with the hydraulic pump 41 on the way, and the return side pipeline 43B is connected to the pump side ports of the tank 42 and the electromagnetic switching valve 44.
And the intermediate port 36B of the tube 36 and the electromagnetic switching valve 44
Supply / discharge conduit 43 connecting the actuator side port of
C, a bottom side port 36A of the tube 36, and another supply / discharge pipe line 43D that connects the rod side port 36C to the actuator side port of the electromagnetic switching valve 44. The supply / discharge pipe lines 43C and 43D are connected to the electromagnetic switching valve 44 when the electromagnetic switching valve 44 is in the stop position (a).
Further, the other supply / discharge pipe line 43D is branched on the way and is individually connected to the bottom side port 36A and the rod side port 36C.

Reference numeral 44 denotes an electromagnetic switching valve as a switching valve provided in the middle of the pipe 43, and the electromagnetic switching valve 44 is connected to a controller 50 described later, and the controller 5
A command signal from 0 switches between the stop position (a) and the supply / discharge position (b). Here, the electromagnetic switching valve 44
Is in the stop position (a), the supply side conduit 43A is shut off, and the supply / discharge conduits 43C and 43D are connected to the return conduit 43B.
When the cab main body 22 vibrates, the rod 38 of the hydraulic cylinder 35 expands and contracts,
When the rod 38 expands and contracts, a damping force is generated as described below.

That is, when the rod 38 extends from the contracted position shown in FIG. 5, the pressure oil in the oil chamber B is transferred to the oil passage 40,
It moves to the other supply / discharge pipe line 43D via the oil groove 37A and the bottom side port 36A, and returns from the supply / discharge pipe line 43D via the electromagnetic switching valve 44 via the one supply / discharge pipe line 43C. It moves to the inside of the passage 43B, and from the return side pipeline 43B through the inside of the electromagnetic switching valve 44, one supply / discharge pipeline 43C, the intermediate port 3
6B, the oil groove 37A, and the oil passage 40 to flow into the oil chamber B. Then, during this time, a damping force is generated in the piston 37 by the flow resistance when the pressure oil flows through the throttle portions 39A, 40A.

Further, at this time, the hydraulic cylinder 35 is rotated between the brackets 29 and 31 independently of the link mechanism 32, and like the oil damper 26 of each lower cushion support 25, the hydraulic cylinder 35 is mounted above the operator cab body 22. ， It is designed to dampen downward vibration.

On the other hand, the electromagnetic switching valve 44 is at the supply / discharge position (b).
When the hydraulic cylinder 35 is in the
The tube 36 provided with 6C functions as a valve casing, and the piston 37 provided with the oil grooves 37A and 37B, the lands 37C to 37E, and the oil passages 39 and 40 functions as a spool. Depending on the position of the piston 37, the oil grooves 37A and 37B and the lands 37C to 37E are arranged in the oil chambers A and B and the ports 36A to 3 respectively.
6C is switched and connected, and operates as a piston position control valve that automatically returns the piston 37 to the neutral position in the tube 36.

That is, as shown in FIG. 7, when the rod 38 is in the contracted position, the pressure oil from the supply-side conduit 43A causes the electromagnetic switching valve to supply and discharge conduit 43C, the oil groove 37B, and the oil passage. Three
9 into the bottom side oil chamber A, the rod side oil chamber B, the oil passage 40, the oil groove 37A, the bottom side port 36A, the other supply and discharge conduit 43D, the electromagnetic switching valve 44, the return side conduit 43B. Flow out into the tank 42 via the
Move in the direction of extension. If the central land 37C of the piston 37 closes the intermediate port 36B, the piston 3
7 stops moving, and the rod 38 of the hydraulic cylinder 35 returns to the intermediate position shown in FIG. Also, as shown in FIG.
When the rod 38 is in the extended position, the supply side pipe 43A
The pressure oil from the oil flows into the rod side oil chamber B through the electromagnetic switching valve 44, the one supply / discharge pipe line 43C, the oil groove 37A, and the oil passage 40, and the bottom side oil chamber A has the oil passage 39 and the oil groove 37B. , The rod side port 36C, and the other supply / discharge pipe line 43D through the tank 4
2, the piston 37 is moved in the contracting direction of the rod 38 until the land 37C at the center of the piston 37 closes the intermediate port 36B, and the hydraulic cylinder 35 returns to the intermediate position shown in FIG.

Thus, when the electromagnetic switching valve 44 is at the supply / discharge position (b), the pressure of the pressure oil discharged from the hydraulic pump 41 keeps the hydraulic cylinder 35 at a constant length, and the hydraulic cylinder 35 is kept in the cab body. It rotates in parallel with the link mechanism 32 in response to the vibration of 22. As a result, horizontal vibration with respect to the cab body 22 can be converted into upward and downward vibrations to prevent the cab body 22 from pitching in the front-rear direction.

In FIG. 3, reference numeral 45 designates a bypass conduit for connecting the supply-side conduit 43A and the return-side conduit 43B.
Reference numeral 6 is a relief valve provided in the middle of the bypass pipe 45, and the relief valve 46 sets the maximum discharge pressure of the hydraulic pump 41.

Next, in FIG. 3, reference numeral 47 denotes an inclination angle sensor as an inclination state detector provided on the revolving frame 21, and the inclination angle sensor 47 is connected to the controller 50 and the inclination angle α of the revolving frame 21. Is output to the controller 50.

Reference numeral 48 denotes a pressure sensor as a work / stop state detector. The pressure sensor 48 supplies the boom cylinder 17D, arm cylinder 17E, bucket cylinder 17F, turning motor (not shown) and the like of the working device 17. The pressure sensor 48 is provided in the middle of a pilot switching valve or a pilot pipe (not shown) for controlling the pressure oil, and the output side of the pressure sensor 48 is connected to the controller 50. Then, the pressure sensor 48 detects the pilot pressure β which changes according to the operation position of the work lever provided in the cab main body 22, and the pilot pressure β is detected by the controller 50.
It is designed to output to.

Reference numeral 49 denotes a pressure sensor as a running / stopping state detector, which is provided in the middle of a pilot switching valve or pilot pipe (not shown) for controlling the pressure oil supplied to the running motor. The output side of the pressure sensor 49 is connected to the controller 50.
The pressure sensor 49 detects a pilot pressure γ that changes according to the operating position of a traveling lever provided in the cab main body 22, and the pilot pressure γ is used as the controller 5
It outputs to 0.

Reference numeral 50 designates a controller as a control means composed of a microcomputer and the like.
0 indicates that each of the sensors 47 to 49 has an input side as shown in FIG.
The output side is connected to the electromagnetic switching valve 44. Then, the controller 50 stores the program and the like shown in FIG. 10 in its storage circuit and controls the switching of the electromagnetic switching valve 44. In the storage circuit of the controller 50, the allowable value α0 as a dead zone for the tilt angle α of the turning frame 21 is stored in the storage area 50A, and whether or not the tilt angle α of the turning frame 21 is larger than the allowable value α0. To judge. In the storage area 50A, an allowable value β0 for the operation amount of the work lever is stored, and when the pilot pressure β is larger than the allowable value β0, the swing motor and the hydraulic cylinders 17D to 17F of the working device 17 are operating. I am able to judge that. Further, the allowable value γ0 as a dead zone for the operation amount of the traveling lever is stored in the storage area 50A, and when the operation amount of the traveling lever (pilot pressure γ) is smaller than the allowable value γ0, the lower traveling body 1 is It is possible to determine when it is time to stop or to start running.

The present embodiment has the configuration described above. Next, the control processing of the electromagnetic switching valve 44 by the controller 50 will be described.

First, when the processing operation is started, the tilt angle α of the revolving frame 21 is read from the tilt angle sensor 47 in step 1, and the pilot pressure β corresponding to the operation position of the work lever is read from the pressure sensor 48 in step 2. Put in. Then, in step 3, the pilot pressure γ that changes according to the operating position of the traveling lever is read from the pressure sensor 49.

In step 4, it is judged whether or not the tilt angle α of the turning frame 21 is larger than the allowable value α0, and "NO".
If it is determined that the tilt angle α of the revolving frame 21 is within the allowable range and is in the horizontal state, the process proceeds to step 5.

In the next step 5, it is judged whether or not the pilot pressure β according to the operating position of the work lever is larger than the allowable value β0. When the judgment is "NO", the lower traveling body 1 is in the traveling state. Since it can be determined that there is, the process proceeds to step 6.

In the next step 6, it is determined whether or not the amount (pilot pressure γ) is larger than the allowable value γ0 according to the operating position of the traveling lever. When the determination is "YES", the lower traveling body 1 Since it can be determined that the vehicle is running, the process proceeds to step 7 and the electromagnetic switching valve 44 is set to the stop position (a).
A command signal for switching to is output, and the process proceeds to step 8 and returns. As a result, the hydraulic cylinder 35 operates as a hydraulic shock absorber that generates a desired damping force.

On the other hand, if "YES" is determined in step 4, it means that the inclination angle α is out of the allowable value α 0 range and the revolving frame 21 is largely inclined. Therefore, the process proceeds to step 9 and the electromagnetic switching valve 44 is moved. A command signal for switching to the feeding / discharging position (B) is output, and the process proceeds to step 8 and returns.

If "YES" is determined in step 5, it means that the working device 17 or the like of the hydraulic excavator is in operation. Therefore, the process proceeds to step 9 and the electromagnetic switching valve 44 is moved to the supply / discharge position (b). A command signal for switching is output, and the process proceeds to step 8 and returns.

Further, when it is determined to be "NO" in step 6, it can be determined that the traveling lever is operated within the allowable value γ0 and the lower traveling body 1 is stopped (or the traveling is started). In step 9, a command signal for switching the electromagnetic switching valve 44 to the feeding / discharging position (b) is output, and in step 8, the process returns. By setting the electromagnetic switching valve 44 to the supply / discharge position (b) in this manner, the hydraulic cylinder 35 is locked and operates as a rigid body.

Thus, in the present embodiment, the revolving frame 2
Brackets 30, 30 provided on the support portion 21B of No. 1 and brackets 28 provided on the front side of the floor plate 24 of the cab body 22,
And a bracket 29 provided on the rear side of the floor plate 24 of the operator's cab body 22 by rotatably connecting them to each other via a link mechanism 32.
A hydraulic cylinder 35 is rotatably connected between the hydraulic cylinder 35 and the bracket 31 provided on the support portion 21B of the swivel frame 21, and the oil chambers A and B of the hydraulic cylinder 35 are connected to the hydraulic pump 41.
A switching valve 4 for switching between a pressure oil supply / discharge position (b) and a stop position (a) in the middle of a pipeline 43 connected to the tank 42 and the tank 42.
4 is provided, for example, when the hydraulic excavator starts running,
At the time of stopping the traveling, at the time of working by operating the working device 17,
When the driver's cab main body 22 vibrates greatly in the front-back direction on the support portion 21B of the revolving frame 21, the electromagnetic switching valve 44 is switched to the supply / discharge position (b) to prevent the vibration transmitted to the driver's cab main body 22 in the front-rear direction. By the parallel link including the hydraulic cylinder 35 and the link mechanism 32, it is possible to convert the vibration to the vertical direction, and it is possible to reliably prevent the operator's cab main body 22 from being greatly pitched in the front-rear direction.

A link mechanism 32 for connecting the floor plate 24 of the cab body 22 to the support portion 21B of the swivel frame 21.
The left and right link members 33, 33 and the respective link members 3
And a connecting member 34 for connecting the three to form a substantially H shape,
Since the connection member 34 is configured to apply an anti-twisting force between the link members 33, even if the operator cab body 22 vibrates in the left-right direction, for example, when the upper swing body 3 makes a swing motion, It is possible to effectively prevent the driver's cab body 22 from rolling in the left-right direction by restricting each link member 33 from rotating independently by the anti-twisting force of the connecting member 34. The safety and strength problems such as the collision of 22D with surrounding members such as the boom cylinder 17D can be reliably solved.

By providing the damping force variable hydraulic cylinder 35 between the revolving frame 21 and the floor plate 24,
The hydraulic cylinder 35 can be housed compactly, and the cab 6
The riding comfort can be improved without increasing the size of the vehicle.

Further, the tilt angle sensor 47 and the pressure sensor 4
Since the signals from 8 and 49 are processed by the controller 50 to control the switching of the electromagnetic switching valve 44, for example, when the hydraulic excavator is on a sloping ground, the electromagnetic switching valve 44 is set to the supply / discharge position (b). By switching and forming a parallel link with the hydraulic cylinders 35, it is possible to prevent the operator's cab main body 22 from greatly tilting or coming into contact with the working device 17 or the like on the revolving frame 21. In addition, the hydraulic cylinder 3 can be operated according to the conditions of vibration applied to the cab body 22 during traveling or work.
It is possible to automatically control so that the riding comfort is always good by giving 5 a damping force or by fixing it to a fixed length to form a parallel link.

Then, each lower cushion support 25 for supporting the cab body 22 on the swivel frame 21 via the floor plate 24.
Is composed of the oil damper 26 and the coil spring 27, and the vertical vibration of the cab main body 22 can be buffered with a small spring constant, so that the natural frequency of the entire cab 6 can be more reliably compared with that of the prior art. It is possible to reduce the size, and in particular, it is possible to effectively dampen the vertical vibration transmitted to the cab main body 22 during traveling of the hydraulic excavator.

Therefore, according to this embodiment, the cab body 2
It is possible to reliably suppress the pitching of 2 on the revolving frame 21 in the front-rear direction by the parallel link formed by the combination of the link mechanism 32 and the hydraulic cylinder 35, and each link member 33 of the link mechanism 32 is separated by the connecting member 34. It is possible to prevent the driver's cab main body 22 from rolling in the left-right direction by preventing the driver's cab main body 22 from rolling in the horizontal direction, and it is possible to solve a problem in safety and strength such as the driver's cab main body 22 colliding with surrounding members.

By using the oil damper 26 and the coil spring 27 in combination as the lower cushioning supports 25, the natural frequency of the entire cab 6 can be reduced and the vertical vibration can be effectively damped. The riding comfort of the vehicle can be significantly improved.

Next, FIGS. 11 and 12 show the second embodiment of the present invention.
This embodiment is characterized in that a shock absorber between the cab body and the swing frame is provided on the rear surface portion of the cab body. 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.

In the figure, reference numerals 51 and 51 denote brackets provided on the lower surface of the floor plate 24. The bracket 51 is composed of two parallel plates substantially like the bracket 28 described in the first embodiment. Although each of the brackets 51 is provided so as to project from the 24 toward the turning frame 21 side, each bracket 51 is formed with a projecting dimension larger than that of the bracket 28.

Further, between the brackets 51, 51 and the brackets 30, 30 of the revolving frame 21 are shown in FIG.
As shown in, the link mechanism 32 is rotatably attached so that each link member 33 becomes horizontal when the cab main body 22 is in a stationary state.

Reference numeral 52 denotes a support column which is erected on the revolving frame 21 so as to be separated from the rear surface portion 22C of the cab main body 22 to the rear side, and a bracket 53 formed of two plates is projectingly formed on the uppermost part of the support column 52. Has been done.

Reference numeral 54 denotes a bracket provided on the rear surface portion 22C of the cab main body 22 so as to face the bracket 53. Between the bracket 54 and the bracket 53, as shown in FIG. The hydraulic cylinder 55, which is similar to the hydraulic cylinder 35 described in the embodiment of FIG.
The tube 56 and the rod 57 are pin-joined and rotatably connected to each other so as to form a parallel link with 2. Then, the hydraulic cylinder 55 processes the detection signals from the tilt angle sensor 47 and the pressure sensors 48 and 49 by the controller 50, as in the first embodiment, and sets the electromagnetic switching valve 44 to the stop position (a). Switching control is performed to the feeding / discharging position (b).

Although this embodiment having the above-described structure has substantially the same effect as that of the first embodiment, the hydraulic cylinder 55 is especially used in the cab main body 2 in this embodiment.
Since the hydraulic cylinder 55 and the link mechanism 32 form a parallel link provided on the rear surface portion 22C of the second rear surface 22C, the distance between the link mechanism 32 and the hydraulic cylinder 55 can be set large, and vibrations with a large amplitude can be prevented. Also, the cab main body 22 can be stably supported on the revolving frame 21.

Further, the link mechanism 3 forming a parallel link
Since the hydraulic cylinder 55 and the hydraulic cylinder 55 are combined so as to be horizontal when the cab body 22 is stationary, the displacement of the cab body 22 in the front-rear direction when the parallel link rotates can be restricted to a small amount. .

In each of the above-mentioned embodiments, each lower cushioning support 25 is described as being constituted by the oil damper 26 and the coil spring 27, but the present invention is not limited to this, and for example, the drawings described in the prior art. Anti-vibration rubber 12 shown in 15
The lower cushioning support 11 made of, for example, may be used. In this case, the gap S shown in FIG. 15 may be increased to about 5 to 30 mm, and the spring constant of the antivibration rubber 12 may be set small. . Further, in each of the above-described embodiments, the hydraulic excavator has been described as an example, but the present invention is not limited to this, and can be applied to, for example, a work machine such as a wheel hydraulic excavator provided with a cab or a hydraulic crane.

Further, as the switching valve, the electromagnetic switching valve 44 having 4 ports and 2 positions has been exemplified, but a directional switching valve of other type such as a switching port having 4 ports and 3 positions may be used, or the switching valve may be replaced with an electromagnetic switching valve. Alternatively, a hydraulic directional control valve or a manual directional control valve may be used.

[0095]

As described above in detail, according to the first to fourth aspects of the present invention, the cab main body and the frame are extended by extending in the front-rear direction between the cab main body and the frame. A link mechanism that is movably connected, and a hydraulic cylinder that is separated from the link mechanism in the front-rear direction of the cab body and is rotatably connected to the cab body and the frame, and that forms a parallel link with the link mechanism. Is provided, and a switching valve for switching between the pressure oil supply / discharge position and the stop position is provided in the middle of the pipeline connecting each oil chamber of the hydraulic cylinder to the hydraulic source and the tank. By controlling the switching of the switching valve based on the above, for example, the switching valve is automatically switched according to the vibration state of the working machine or the working state or the sloped state of the terrain, and the switching valve is set at the supply / discharge position. Hydraulic oil is supplied from the hydraulic source. When the switching valve is switched to the supply / discharge position, the hydraulic cylinder is connected to the tank by shutting off the oil chamber of the hydraulic cylinder from the hydraulic source at the stop position and communicating with the tank. The piston is fixed in the tube of, and the parallel link is constituted by the hydraulic cylinder and the link mechanism, so that when the driver's cab main body vibrates on the frame, the parallel link rotates in conjunction with the driver's cab main body. The vibration in the horizontal direction, for example, the vibration in the front-rear direction can be converted into the vibration in the vertical direction, whereby the vibration in the horizontal direction can be restricted to a small level, and the vibration (pitching) in the front-rear direction of the cab main body can be reliably reduced. On the other hand, when the switching valve is switched to the stop position, the rod of the hydraulic cylinder can be expanded and contracted, and it is possible to allow the hydraulic cylinder and the link mechanism to perform different rotational movements from each other. It is possible to elastically support the frame via the lower cushion supports, and softly absorb vibrations from the frame by the lower cushion supports and the hydraulic cylinders.

Further, according to the invention described in claim 5, the hydraulic cylinder is provided with the hydraulic power source so as to automatically return the piston to the intermediate position in the tube when the switching valve is at the supply / discharge position. By providing a piston position control valve that supplies and discharges pressure oil from each oil chamber, the hydraulic cylinder can be fixed to a fixed length simply by switching the switching valve to the supply and discharge position.
A parallel link can be quickly constructed from the hydraulic cylinder and the link mechanism.

According to the invention described in claim 6,
If the valve casing of the piston position control valve according to the fifth aspect is configured by the tube of the hydraulic cylinder and the spool is integrally formed by the piston, the number of components can be reduced and the overall size can be reduced.

According to a seventh aspect of the invention, the link mechanism includes a pair of link members extending in the front-rear direction between the floor plate of the cab body and the frame and spaced apart in the left-right direction. Even if a force that vibrates the driver's cab main body in the left-right direction acts on the frame, the link member is composed of a connecting member that connects the link members in the left-right direction so that the rotation of the link member is synchronized. Further, it is possible to prevent the driver's cab body from rolling in the left-right direction, and it is possible to solve the safety and strength problems such as the driver's cab body colliding with surrounding members.

Further, in the invention according to the eighth aspect, by disposing the hydraulic cylinder between the floor plate and the frame, it is possible to prevent the cab from becoming large.

Further, in the invention according to claim 9, the battle hydraulic cylinder is provided between the pillar standing upright from the frame and the rear surface portion of the operator's cab body, so that the operator's cab body is protected against a large vibration. Can be supported in a stable state, and an effective vibration damping effect can be obtained.

According to the tenth aspect of the present invention, each of the lower cushioning supports is composed of a coil spring and an oil damper for cushioning the vibration of the cab body with a relatively small spring constant. The natural frequency of the whole can be surely made smaller than that of the prior art, and the vertical vibration transmitted to the cab body can be effectively damped.

[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 sectional view taken along line II-II in FIG.

[Fig. 3] A controller for a hydraulic cylinder, an electromagnetic switching valve, etc.
It is a hydraulic circuit diagram shown with each sensor.

FIG. 4 is a vertical sectional view showing a structure of a hydraulic cylinder.

FIG. 5 is a view for explaining a communication state between each port and the oil passage when the electromagnetic switching valve is at the stop position and the rod is at the contracted position.
It is a longitudinal cross-sectional view similar to FIG.

FIG. 6 is a view for explaining a communication state between each port and the oil passage when the electromagnetic switching valve is at the stop position and the rod is at the extension position.
It is a longitudinal cross-sectional view similar to FIG.

FIG. 7 is a view for explaining a communication state between each port and the oil passage when the electromagnetic switching valve is at the supply / discharge position and the rod is at the contracted position.
It is a longitudinal cross-sectional view similar to FIG.

FIG. 8 is a view for explaining a communication state between each port and the oil passage when the electromagnetic switching valve is at the supply / discharge position and the rod is at the intermediate position.
It is a longitudinal cross-sectional view similar to FIG.

FIG. 9 is a view for explaining a communication state between each port and the oil passage when the electromagnetic switching valve is in the supply / discharge position and the rod is in the extended position.
It is a longitudinal cross-sectional view similar to FIG.

FIG. 10 is a flowchart showing a control process of an electromagnetic switching valve by a controller.

FIG. 11 is a partially cutaway external view showing a cab body, a swivel frame, and the like according to a second embodiment of the present invention.

12 is a sectional view taken along the arrow XII-XII in FIG.

FIG. 13 is an overall view showing a hydraulic excavator according to a conventional technique.

FIG. 14 is a partially broken external view showing an enlarged view of the swivel frame and the cab body in FIG.

FIG. 15 is an enlarged cross-sectional view of the lower cushioning support and the like shown in FIG.

FIG. 16 is an explanatory diagram for analyzing vibration in a cab.

FIG. 17 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]

 1 Lower Traveling Body 3 Upper Revolving Body (Work Machine Main Body) 6 Driver's Cab 21 Revolving Frame (Frame) 22 Operator's Cabin Body 24 Floor Plate 25 Lower Buffer Support 26 Oil Damper 27 Coil Spring 28, 30, 51, 53 Bracket 32 Link Mechanism 33 Link member 34 Connection member 35,55 Hydraulic cylinder (piston position control valve) 36,56 Tube (valve casing) 37 Piston (spool) 38,57 Rod 39A, 40A Throttling part (damping force generating mechanism) 41 Hydraulic pump (hydraulic pressure) Source) 42 Tank 43 Pipe line 44 Electromagnetic switching valve (switching valve) 47 Tilt angle sensor (tilt state detector) 48 Pressure sensor (work / stop state detector) 49 Pressure sensor (run / stop state detector) 50 Controller ( Control means) 52 Strut A Bottom side oil chamber B Rod side oil chamber

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Zenji Kaneko 650 Jinrachi-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd. Tsuchiura factory (72) Inventor Koji Tahara 650 Kintate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction (72) Inventor Fumio Fukusa, 650 Kintate-cho, Tsuchiura-shi, Ibaraki Hitachi Construction Machinery Co., Ltd., Tsuchiura Plant

Claims (10)

[Claims] 1. A frame of a work machine main body, a box-shaped driver's cab main body provided on the frame and provided with a floor plate on the lower surface side, and a plurality of boxes between the floor plate of the operator's cab main body and the frame. A working machine with a cab provided with a lower cushioning support for cushioning transmission of vibrations from the frame to the cab main body, in a front-back direction extending between the cab main body and the frame. , A link mechanism rotatably connected to the cab body and the frame at both ends, and spaced apart from the link mechanism in the front-rear direction of the cab body, and both ends rotatable to the cab body and the frame, respectively And a hydraulic cylinder that forms a parallel link together with the link mechanism. The hydraulic cylinder includes a tube, a piston that defines the inside of the tube into two oil chambers, and one end side fixed to the piston. , A rod whose other end projects outside the tube, and a damping force generation mechanism that generates a damping force in the pressure oil flowing between the oil chambers when the rod expands and contracts, and each of the hydraulic cylinders A switching valve for switching between a pressure oil supply / discharge position and a stop position is provided in the middle of a pipeline connecting the oil chamber to the oil pressure source and the tank. Work with a cab characterized in that oil is supplied to and discharged from each oil chamber of the hydraulic cylinder, and at the stop position each oil chamber of the hydraulic cylinder is shut off from the hydraulic pressure source and communicated with the tank. Machine. 2. The working machine main body is provided with an operating state detecting means for detecting an operating state of the working machine main body, and between the operating state detecting means and the switching valve, the operating state detecting means is provided. The working machine with a cab according to claim 1, further comprising control means for switching and controlling the switching valve based on a signal. 3. A running / stopping state detector for detecting a running / stopping state of a working machine from an operating position of a running lever provided in the driver's cab main body; 2. The work machine with a cab according to claim 1, comprising a work / stop state detector for detecting a work / stop state of the work machine from an operating position of a work lever provided on the work machine. 4. The working machine with a cab according to claim 1, wherein the operating state detecting means is provided on a frame of the working machine main body, and is composed of a tilt detecting means for detecting a tilt of the frame. 5. The hydraulic cylinder is provided with pressure oil from the hydraulic source in each oil chamber so that the piston automatically returns to an intermediate position in the tube when the switching valve is at the supply / discharge position. The working machine with a cab according to claim 1, further comprising a piston position control valve for supplying and discharging. 6. The piston position control valve comprises a valve casing constituted by a tube of the hydraulic cylinder, and a spool integrally formed by the piston.
Work machine with cab as described in. 7. The link mechanism extends in the front-rear direction between the floor plate of the cab body and the frame, and a pair of link members spaced apart in the left-right direction is synchronized with the rotation of each link member. A linking member that links the link members in the left-right direction, and both ends of the link member in the front-rear direction are rotatably connected to the floor plate and the frame of the cab body. The working machine with a cab according to 1. 8. The hydraulic cylinder is arranged between the frame of the working machine body and the floor plate of the cab body.
Work machine with cab as described in. 9. The work machine with a cab according to claim 1, wherein the hydraulic cylinder is arranged between a support column standing upright from a frame of the work machine main body and a rear surface portion of the cab main body. 10. The work machine with a cab according to claim 1, wherein each of the lower cushioning supports is composed of a coil spring and an oil damper that cushion a vibration of the cab body with a relatively small spring constant. .