KR20140145976A - Oil pressure device of multi-stage arm and deeply excavating excavator - Google Patents

Abstract

There is an improvement in operational efficiency of an oil pressure cylinder of an oil pressure device having a multi-stage arm. The present invention is characterized by being provided with a multi-stage arm driving mechanism configured to contract the multi-stage arm by extending the oil pressure cylinder and to extend the multi-stage arm by contracting the oil pressure cylinder; an oil pressure circuit configured to extend and contract the oil pressure cylinder; the oil pressure circuit having a control valve to control the flow of pressurized oil into the oil pressure cylinder; a counterbalance valve provided in a first flow path between a bottom side fluid chamber of the oil pressure cylinder and the control valve; a relief valve wherein a first side is connected to a flow path between the bottom side fluid chamber and the counterbalance valve, among the first flow path, and a second side connected to a second flow path; and a conversion valve configured to flow pressurized oil in the second flow path to a low pressure side when the oil pressure cylinder is extended.

Description

TECHNICAL FIELD [0001] The present invention relates to a multi-stage hydraulic system and a deep excavator,

The present invention relates to a hydraulic apparatus for a multi-stage arm and a deep drawing excavator.

Generally, in the case of digging ground depth deep in civil works, a deep excavator is suitably used. This deep excavator has a boom which is installed so as to be freely buoyable to the vehicle body, a boom which is installed so as to extend in the upward and downward directions of the boom, and which is capable of being stretched inside the outer cylinder and the outer cylinder A retractable cylinder having a plurality of inner cylinders accommodated therein, a retractable arm fixed to the outer cylinder, a retractable cylinder arranged along the longitudinal direction of the outer cylinder, and a sheave mounting member mounted on the retractable cylinder and moving in the longitudinal direction of the outer cylinder And the other end side of the movable sheave is engaged with the outer cylinder and the other end side of the movable sheave is engaged with the inner cylinder. And a stretch rope wound around the movable sheave for stretching and shrinking.

In this deep excavator according to the related art, the expansion / contraction cylinder is contracted in a state where the expansion / contraction arm provided at the front end side of the boom is held perpendicular to the ground, thereby extending the inner cylinder of the expansion / contraction arm from the outer cylinder. A clam shell bucket is mounted on the distal end portion (lower end portion) of the inner tube, and the clam shell bucket can excavate the gravel.

After holding the excavated soil by grasping the clay shell bucket, the expansion and contraction cylinder is extended, and the clam shell bucket is opened in a state in which the inner cylinder is pulled up into the outer cylinder by the expansion and contraction rope, (See Patent Document 1).

Japanese Patent Application Laid-Open No. 62-82131

In the deep-drawn excavator according to the above-described prior art, a tube of the extensible cylinder is mounted on the outer cylinder of the extensible arm, and a sheave mount (hanger) for supporting the extendable movable sheave is mounted on a rod projecting downward from the tube .

Therefore, in the deep-drawn excavator according to the related art, the rod of the extensible cylinder is extended downward to move the sheave mount downward, so that the distance between the movable sheave for expansion and contraction supported by the sheave mount and the fixed sheave for expansion The rope for retracting and shrinking is wound on the inner surface of the outer tube and the inner tube to which the rope for retracting is held can be pulled up into the outer tube.

However, in the deep-drawn excavator of the prior art, since the tube of the extensible cylinder is mounted on the outer cylinder, the sheave mount is moved downward by the extensible cylinder, and the stretchable rope The weight of the sheave mount is applied to the stretch rope, but the weight of the tube of the stretch cylinder does not act. In this way, when lifting the inner cylinder to the outer cylinder together with the soil excavated by the clam shell bucket, the weight of the extensible cylinder itself can not be used as a pulling force, and there is a possibility that the lifting operation of the inner cylinder by the extensible cylinder can not be efficiently performed .

(1) According to a first aspect of the present invention, there is provided a hydraulic device for a multi-stage arm, comprising: a multi-stage arm driving mechanism for shrinking a multi-stage arm by extension of a hydraulic cylinder and extending the multi- The hydraulic circuit is provided with an extension position for extending the hydraulic cylinder to control the flow of the pressure oil to the hydraulic cylinder, a contraction position for contraction of the hydraulic cylinder, and supply of pressure oil to the hydraulic cylinder, A second flow path between the oil chamber of the bottom side of the hydraulic cylinder and the control valve and a second flow path between the load side chamber of the hydraulic cylinder and the control valve, A counterbalance valve installed in the first flow path, and a primary side connected to a flow path between the bottom side chamber and the counterbalance valve in the first flow path, A relief valve to which the secondary side is connected to the two-way valve, a permitting position allowing the pressure oil of the second flow path to flow to the low pressure side at the time of extension of the hydraulic cylinder, And a switching valve which is switched to a forbidden position for prohibiting flow of the refrigerant.

(2) According to a second aspect of the present invention, in the hydraulic apparatus of the multi-stage arm according to the first aspect, the hydraulic circuit is installed in series with the counterbalance valve and the control valve in the flow path between the counterbalance valve and the control valve And a slow return valve having a variable throttle.

(3) According to a third aspect of the present invention, in the hydraulic apparatus of the multi-stage arm according to the first aspect, the switching valve is switched to the permitting position when the control valve is switched to the extension position, .

(4) According to a fourth aspect of the present invention, a deep excavator according to the invention comprises: a body which can be freely installed; a boom provided so as to be able to stow the vehicle body; A hydraulic cylinder arranged along the longitudinal direction of the outer cylinder constituting the multi-stage arm, a fixed sheave for extension and retraction fixed to the outer cylinder, and a hydraulic cylinder And a movable sheave for expanding and retracting, which is provided in the sheave mounting opening, and a movable sheave which has one end engaged with the outer cylinder and the other end of which is connected to the other end of the inner cylinder And a stretchable rope wound around a movable sheave for stretching and retracting, the stretchable rope being engaged with an inner tube serving as an inner side, In the deep drawing excavator, the hydraulic cylinder has a tube, a rod having one side fixed to the piston in the tube and the other side projecting from the tube to the outside, and the rod of the hydraulic cylinder in an upward state , The distal end portion of the rod is mounted on the outer cylinder of the stretching arm and the tube of the hydraulic cylinder is made a free end while the sheave mounting portion is mounted on the tube of the hydraulic cylinder and the multi- And a hydraulic device of the present invention.

(5) According to a fifth aspect of the present invention, in the deep groove excavator described in the fourth aspect, the front end of the rod of the hydraulic cylinder is mounted on the upper side of the outer cylinder.

According to the present invention, the hydraulic cylinder can be operated efficiently.

1 is a side view showing a deep drawing excavator according to an embodiment of the present invention in a state in which the expansion and contraction arm is minimized.
2 is a side view showing the deep drawing excavator in a state in which the stretching arm is extended most.
Fig. 3 is a side view showing the expansion and contraction arm in Fig. 1 alone. Fig.
Fig. 4 is a front view of the telescopic arm seen in the direction of arrows IV-IV in Fig. 3;
5 is a perspective view showing the stretching and contracting arm as a single body.
6 is a perspective view of a main portion enlarged view showing an outer cylinder, a stretching cylinder, a retracting fixed sheave, a sheave mounting opening, a retractable movable sheave, a sheave mounting guide rail, and the like in Fig.
7 is a perspective view of a main portion enlarged view showing a sheave mount, a movable sheave for stretching, a movable sheave for pushing, a sheave mounting guide rail, and the like.
Fig. 8 is a front view of a main portion enlarged view showing the expansion sheave for expansion and contraction in Fig. 4 and the like.
9 is a schematic diagram showing a telescopic arm extension / contraction mechanism in a state in which the telescopic arm is contracted.
10 is a schematic diagram showing a telescopic arm extending and contracting mechanism in a state in which the telescopic arm is stretched.
11 is a cross-sectional view of the telescopic arm, the boom bracket, and the like as viewed in the direction of arrows XI-XI in FIG.
12 is a sectional view of the telescopic arm, the telescopic cylinder, the sheave mount, the telescopic sheave, and the like as viewed in the direction of arrows XII-XII in Fig.
Fig. 13 is a sectional view of the telescopic arm, the telescopic cylinder, the sheave mount, the movable sheave for pushing, and the like as viewed in the direction of arrows XIII-XIII in Fig.
Fig. 14 is a cross-sectional view of the telescopic arm, sheave mounting opening, pushing fixed sheave, and the like as viewed in the direction of arrows XIV-XIV in Fig. 3;
Fig. 15 is a side view showing a state in which the expandable arm is placed on the ground with the deep-drawn excavator as a transport posture.
Fig. 16 is a front view showing a modification in which a stretching cylinder, a retracting fixed sheave, a sheave attaching squeeze, a movable sheave for stretching, and a sheave mounting guide rail are arranged on the front side of the outer cylinder.
17 is a diagram showing the entire configuration of a hydraulic device.

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, embodiments of a hydraulic apparatus and a deep drawing excavator according to the present invention will be described in detail with reference to the accompanying drawings.

1, reference numeral 1 denotes a deep shovel excavator according to the present embodiment. The deep shovel excavator 1 comprises a lower traveling body 2 of a crawler type which can be freely freely pivoted on the lower traveling body 2, And a vehicle body composed of an upper swing body 3 mounted thereon.

The upper revolving structure 3 includes a revolving frame 3A as a base and a cap 3B disposed on the left side of the revolving frame 3A at the front side, A counterweight 3C, and a structure cover 3D that houses therein equipment such as an engine, a hydraulic pump, etc. (all of which are not shown in Fig. 1).

4 shows a boom installed on the front side of the upper revolving structure 3 so as to be able to move. The proximal end side of the boom 4 is attached to the front side of the revolving frame 3A and the excavator device 11 to be described later is attached to the distal end side of the boom 4. A boom cylinder 4A is provided between the boom 4 and the revolving frame 3A and the boom 4 moves to the upper revolving body 3 by expanding and contracting the boom cylinder 4A. The bottom side of the excavator rocking cylinder 4B is mounted on the upper face side of the boom 4 and the rod side of the excavator rocking cylinder 4B is mounted on the excavator 11. [

Next, a description will be given of an excavator 11 mounted on the front end side of the boom 4 for excavating deep-sea deep wells.

Reference numeral 11 denotes an excavating apparatus mounted on the front end side of the boom 4. The excavating apparatus 11 includes a multi-stage arm (stretching arm) 12, a stretching cylinder 25, a sheave mounting hole 29 , A fixed sheave (31) for expansion and contraction, a movable sheave (33) for expansion and contraction, and a stretchable rope (34). Reference numeral 111 denotes a multi-stage arm driving mechanism. The multi-stage arm drive mechanism 111 includes the extensible cylinder 25, the sheave mount 29, the fixed sheave 31 for expansion and contraction, the movable sheave 33 for expansion and contraction, And the like.

Reference numeral 12 denotes a telescopic multistage arm (telescopic arm) which is mounted so as to extend in the upward and downward directions on the distal end side of the boom 4. As shown in FIG. 9 and the like, the stretching arm 12 includes an outer tube 13 positioned at the outermost position and a first-stage (second-stage) outer tube 13 which is accommodated in the inner peripheral side of the outer tube 13 in a longitudinal direction And an inner cylinder 23, which will be described later, which is accommodated in the inner circumferential side of the first-stage inner cylinder 21 in such a manner as to extend and retract in the longitudinal direction.

Here, as shown in Figs. 11 to 14, the outer cylinder 13 has a rear surface 13A mounted on the front end side of the boom 4 and a front surface 13A facing the rear surface 13A A left side face 13C and a right side face 13D facing each other in the left and right directions with the front face 13B interposed between the rear face 13A and the front face 13B and between the rear face 13A and the left face 13C And has a hexagonal cross-sectional shape surrounded by a right-side slope 13E arranged obliquely at an oblique angle and a right-side slope 13F slanted at an angle between the rear 13A and the right side 13D.

In this way, a left-side slope 13E is provided between the rear face 13A and the left side face 13C mounted on the front end side of the boom 4, and a right-side slope face 13E is provided between the rear face 13A and the right side face 13D. The buckling strength against the load acting on the outer cylinder 13 can be increased by providing the inclined surface 13F. On the other hand, the upper end portion (upper end portion) 13G and the lower end portion (lower end portion) 13H of the outer cylinder 13 are open ends.

And reference numeral 14 denotes an upper flange plate integrally provided on the outer circumferential side of the outer cylinder 13 in the middle of the outer cylinder 13 in the longitudinal direction. On this upper flange plate 14, one end side 42A of the pushing rope 42 to be described later is engaged. And reference numeral 15 denotes a lower flange plate integrally provided at the lower end of the outer cylinder 13. [ The lower flange plate 15 is engaged with one end 37A of the support rope 37 described later.

And 16 is a sheave mounting opening provided on the lower side of the outer cylinder 13. [ 14, the sheave mounting opening 16 has a portion where the left side 13C and the left side slope 13E constituting the outer cylinder 13 intersect with each other and a portion where the right side 13D and the right side slope 13F intersect, And opens in the inside of the outer cylinder 13. [0051] A part of a pushing sheave 39 for pushing, which will be described later, is inserted into the sheave mounting opening 16.

Reference numeral 17 denotes a pair of left and right boom brackets provided on the outer side of the outer cylinder 13 and below the sheave fittings 29 to be described later. The pair of boom brackets 17 are provided at the front end of the boom 4 Respectively. 5 and 11, the pair of boom brackets 17 are formed of a plate facing each other at intervals in the left-right direction. Each of the brackets 17 is provided with a cylindrical boom- Both sides in the left and right direction of the main body 17A are fixed. The pair of boom brackets 17 are integrally fixed to the rear face 13A of the outer cylinder 13 by means of welding or the like and the boom connecting portion 17A of the boom bracket 17 is fixed to the pin 18 (See Fig. 1). A gap 17B is formed between the pair of boom brackets 17 and a later-described stretching and shrinking cylinder 25 is disposed in the gap 17B.

Reference numeral 19 denotes a pair of left and right cylinder brackets located on the outer side of the outer cylinder 13 and located on the upper side of the boom bracket 17. The pair of cylinder brackets 19 are disposed on the upper side of the boom bracket 17, And is mounted on the rod side. Here, the pair of the cylinder brackets 19 are formed of a plate facing each other at intervals in the left and right directions, and the rod front end portion of the excavator rocking cylinder 4B is connected to a pin hole And is integrally fixed to the rear surface 13A of the outer cylinder 13 at a position near the upper side of the boom bracket 17 by means of welding or the like. The rod end of the excavator rocking cylinder 4B is pin-coupled to the pair of the cylinder brackets 19 so as to be rotatable using the pin 20 (see Fig. 1).

Therefore, by expanding and contracting the excavator rocking cylinder 4B, the outer cylinder 13 of the expansion and contraction arm 12 is moved in the forward and backward directions or in the upward and downward directions about the pin 18 at the tip end side of the boom 4 As shown in Fig. The cylinder bracket 19 may be provided below the boom bracket 17 depending on the mounting position of the excavator rocking cylinder 4B.

Reference numeral 21 denotes an inner cylinder of the first stage as the outermost inner cylinder movably received in the outer cylinder 13 with an appropriate gap therebetween. 11 to 14, the inner cylinder 21 is formed as square cylinders having a rectangular sectional shape surrounded by the rear surface 21A, the front surface 21B, the left surface 21C, and the right surface 21D, Both end portions in the up and down directions are open ends. The inner cylinder 21 is received in the inner side of the outer cylinder 13 from the lower end portion 13H of the outer cylinder 13 and is movable in the longitudinal direction (up and down direction) with respect to the outer cylinder 13. [

A slide plate (not shown) is provided between the inner surface of the outer tube 13 and the outer surface of the inner tube 21 to smoothly slide the inner tube 21 along the outer tube 13. [ On the other hand, a lower flange plate 22 is provided at the lower end portion of the inner cylinder 21, and a later-described fixing securing sheave 35 for support is attached to the lower flange plate 22. [

Reference numeral 23 denotes an inner cylinder located at the innermost position of the inner cylinder 21 which is movably accommodated in the inner cylinder 21 with a suitable gap therebetween. The inner cylinder 23 is formed as an angular cylinder surrounded by the rear face 23A, the front face 23B, the left side face 23C and the right side face 23D and having a rectangular cross sectional shape that is brighter than the inner cylinder 21 have. The inner cylinder 23 is accommodated in the inner cylinder 21 from the lower end side of the inner cylinder 21 and is movable in the longitudinal direction (up and down direction) with respect to the inner cylinder 21. [

A slide plate (not shown) is provided between the inner surface of the inner tube 21 and the outer surface of the inner tube 23 to smoothly slide the inner tube 23 along the inner tube 21. [ On the other hand, a mounting eye 24 is provided on the lower end of the inner cylinder 23, and a clam shell bucket 43 described later is mounted on the mounting eye 24.

Next, a description will be given of the extensible cylinder 25 according to the present embodiment, the tube guide 26 attached to the extensible cylinder 25, the sheave mounting hole guide rail 27, the sheave mounting hole 29, and the like.

And reference numeral 25 denotes a stretching cylinder arranged along the longitudinal direction of the outer cylinder 13 constituting the stretching arm 12. The stretching cylinder 25 includes a tube 25A and a piston 25E slidably installed in the tube 25A (see FIG. 17). One side of the piston 25E is fixed to the piston in the tube 25A, And a rod 25B protruding outward from the outer cylinder 25A.

The extensible cylinder 25 has a structure in which the rod 25B is upwardly moved from the rear face 13A side of the outer cylinder 13 provided with the boom bracket 17 to the center position in the left and right direction of the outer cylinder 13 As shown in Fig. The distal end portion 25C of the rod 25B of the stretching and shrinking cylinder 25 is inserted into the bracket 13J provided in the vicinity of the upper end portion 13G of the outer cylinder 13 with the pin 25D interposed therebetween And is pin-coupled.

On the other hand, the tube 25A of the extensible cylinder 25 extends in the downward direction as a free end and is disposed in the gap 17B formed between the pair of boom brackets 17 in the left and right directions. Further, on the upper side of the tube 25A, a sheave mounting hole 29 described later is mounted. The tube 25A is extended along the outer tube 13 together with the sheave mounting hole 29 by expanding and contracting the extensible cylinder 25 between the latest state shown in Fig. 1 and the state of minimized as shown in Fig. And moves upward and downward.

When the extensible cylinder 25 is brought into the minimized state shown in Fig. 2, the length dimension from the bottom of the tube 25A to the tip end portion 25C (position of the pin 25D) of the rod 25B (The position of the pin 25D connected to the outer cylinder 13) from the upper vicinity portion 13G1 of the outer cylinder 13 (the length of the pin 25D connected to the outer cylinder 13) The length L1 of the extensible cylinder 25 in the minimized state is set to be equal to or smaller than the length L2 of the outer cylinder 13 when the length of the outer cylinder 13 to the lower end portion 13H And is set to approximately one half of the length dimension.

That is, the length L1 of the extensible cylinder 25 in the minimized state and the length L2 of the outer cylinder 13 are set in the following relationship.

More preferably, the length L1 of the extensible cylinder 25 in the minimized state and the length L2 of the outer cylinder 13 are set in the following relationship.

Thus, by setting the length L1 of the minimized cylinder 25 to a length of about 1/2 of the length L2 of the outer cylinder 13, the stroke of the cylinder 25 Can be largely secured. Thus, only by retracting the stretch rope 34 four times between the later-described retractable fixed sheave 31 and the retractable movable sheave 33, the retractable arm 12 is moved to the minimized state shown in Fig. 1 And the latest state shown in Fig.

Reference numeral 26 denotes a tube guide provided on the outer side of the rear surface 13A of the outer cylinder 13. The tube guide 26 accommodates the tube 25A of the stretching and shrinking cylinder 25 movably. 12 and 13, the tube guide 26 is formed by a cylindrical body having a substantially square cross-sectional shape, and is disposed in a gap 17B formed between a pair of boom brackets 17 And is fixed to the rear face 13A of the outer cylinder 13 along its longitudinal direction. The tube 25A of the stretchable cylinder 25 which is a free end can be moved in the longitudinal direction of the outer tube 13 while being guided by the tube guide 26. [

Reference numeral 27 denotes two sheave mounting hole guide rails provided on the outer side of the outer cylinder 13 and each sheave mounting hole guide rail 27 guides a sheave mounting hole 29 to be described later. These two sheave mounting guide rails 27 are arranged on the left and right sides of the rear face 13A of the outer cylinder 13 with the extensible cylinder 25 therebetween.

Here, the sheave mounting guide rail 27 is formed by the respective cylinders having a rectangular cross-sectional shape. The upper end portion of the sheave mounting guide rail 27 is fixed via a bracket 27A in the vicinity of the upper end portion 13G of the outer cylinder 13 and the lower end portion of the sheave mounting port guide rail 27 is fixed to the outer cylinder 13, And is fixed to the upper flange plate 14 via a bracket 27A. The sheave mounting guide rail 27 extends in the longitudinal direction in parallel with the rear surface 13A in a state in which the sheave mounting guide rail 27 is spaced apart from the rear surface 13A of the outer cylinder 13 by a predetermined distance. In this case, by securing the two sheave mounting port guide rails 27 made of square pipes to the outer cylinder 13, the strength of the outer cylinder 13 can be increased.

Reference numeral 28 denotes a sheave mounting substrate fixed to the upper end 13G of the outer cylinder 13. The sheave mounting substrate 28 is to be mounted with a later-described fixed sheave 31 for expansion and the like. The sheave mounting board 28 has a sheave mounting portion 28A extending from the rear face 13A of the outer cylinder 13 to the rear side (boom 4 side), and a sheave mounting portion 28A And a rope lock portion 28B. The sheave mounting portion 28A of the sheave mounting board 28 is rotatably supported by a sheave 31 for expansion and contraction and the rope locking portion 28B is provided with one end side 34A of a later- .

Reference numeral 29 denotes a sheave mount fitted to the tube 25A of the extensible cylinder 25. The sheave mount 29 is mounted with a movable sheave 33 for expansion and contraction which will be described later. 7, 12, and 13, the sheave attachment port 29 includes a main body portion 29A fixed to the upper side of the tube 25A of the extensible cylinder 25, An upper side sheave support portion 29B located on the upper side of the main body portion 29A and rotatably supporting the movable sheave 33 for extension and contraction; a movable sheave 41 for pushing, And a lower sheave support portion 29C for rotatably supporting the lower sheave support portion 29C.

In this case, as shown in Fig. 12, the main body portion 29A of the sheave mounting opening 29 is provided with a pair of left and right sieve mounting opening guide rails 27 slidably inserted into the left and right sieve mounting opening guide rails 27, And the sheave mounting portion 29D is guided by the left and right sheave mounting portion guide rails 27 and is movable in the longitudinal direction (up and down direction) of the outer cylinder 13 .

11 to 13, a tube 25A of a stretching cylinder 25 having a free end provided with a slide plate 30 is provided on an inner side surface of the slide plate 30 So that it can smoothly move along the tube guide 26 in the longitudinal direction of the outer cylinder 13. [

Next, the outer cylinder 13 constituting the stretching arm 12, the inner cylinder 21 of the first stage, the fixed sheave 31 for expansion and contraction for connecting the inner cylinder 23 of the second stage in a stretchable manner, The movable sheave 33, the stretching rope 34, the supporting fixed sheave 35, and the supporting rope 37 will be described.

Here, the stretchable sheave 31, the stretchable sheave 33, the stretchable rope 34, the fixed sheave for support 35 and the support rope 37 are fixed to the outer cylinder 13, Two sets are provided so as to be symmetrical with respect to the left and right sides with respect to the center line 25, and have the same structure. The movable sheave 33 for expansion and contraction, the stretchable rope 34, the fixed sheave for support 35 and the support rope 37 disposed on the left side of the outer cylinder 13 ), And the elements arranged on the right side are denoted by the reference character '' ', and the description thereof is omitted.

Reference numeral 31 denotes a stretchable sheave for extension and retraction which is fixed to the upper end side of the outer cylinder 13 via a sheave mounting substrate 28. The stretchable sheave 31 for expansion and contraction is formed by two fixed sheaves 31A, 31B. One of the fixed sheaves 31A is rotatably supported by the sheave mounting portion 28A of the sheave mounting board 28 via a bracket 32A while the other fixed sheave 31B is supported by the other bracket 32B And is rotatably supported. In this case, the support shafts (not shown) of the respective fixed sheaves 31A and 31B are arranged so as to be non-parallel to the rear surface 13A of the outer cylinder 13, respectively.

Reference numeral 33 denotes an expandable movable sheave rotatably supported by a sheave mount 29. The expandable movable sheave 33 is composed of two movable sheaves 33A and 33B having the same diameter . 12, the one movable sheave 33A and the other movable sheave 33B are connected to one support shaft 33C mounted on the upper sheave support portion 29B of the sheave mounting hole 29, And is rotatably supported adjacent thereto. In this case, the support shafts 33C of the movable sheaves 33A and 33B are arranged parallel to the rear surface 13A of the outer cylinder 13. [ The movable sheave 33 for expanding and shrinking moves up and down the sheave mounting opening 29 as the expansion and contraction cylinder 25 expands and contracts so as to move toward or away from the expansion sheave 31 for expansion and contraction.

In this case, the movable sheave 33 for expansion and contraction supported by the sheave mount 29 is disposed on the outer side of the left side face 13C of the outer cylinder 13, · Face to face in the right direction. This prevents the movable sheave 33 for extension and contraction from projecting greatly toward the rear surface 13A side of the outer cylinder 13 and can reduce the size of the periphery of the movable sheave 33 for expansion and contraction.

Reference numeral 34 denotes a stretch rope connecting between the outer tube 13 and the innermost tube 23 located on the innermost side. The stretchable rope 34 is constituted by a wire rope. 9 and 10, the one end side 34A of the stretchable rope 34 is connected to the rope lock portion 28B of the sheave mounting board 28 provided on the upper end portion 13G of the outer cylinder 13. [ And the other end side 34B of the stretchable rope 34 is retained on the upper side of the inner cylinder 23 which is inserted into the outer cylinder 13 and the inner cylinder 21. [ The intermediate portion of the rope 34 for extension and contraction is composed of two fixed sheaves 31A and 31B constituting the fixed sheave 31 for expansion and contraction and two movable sheaves 31A and 31B constituting the movable sheave 33 for expansion and contraction, And is wrapped about four times between the first and second cams 33A and 33B.

That is, the stretch rope 34 having the one end 34A of which is fixed to the sheave mounting substrate 28 is held by one of the movable sheave 33A of the stretchable movable sheave 33, The other movable sheave 33B of the movable sheave 33 for extension and contraction and the other fixed sheave 31B of the extension and retraction sheave 31 are sequentially wound. The other end side 34B of the stretchable rope 34 is inserted into the outer tube 13 and the inner tube 21 from the other fixed sheave 31B of the retractable fixed sheave 31, As shown in Fig.

As described above, the two movable sheaves 33A and 33B are constituted by the two fixed sheaves 31A and 31B, and the movable sheave 33 for expansion and contraction is constituted by the two movable sheaves 33A and 33B The rope 34 for extension and contraction is wound around the two fixed sheaves 31A and 31B and the two movable sheaves 33A and 33B four times so that the rope for stretching 4 The number of times the stretch rope 34 is brought into contact with the sheave can be reduced by half as compared with a configuration in which the sheave is wiped eight times between the fixed sheave for stretching for shrinking and the movable sheave for stretching for four times.

And reference numeral 35 denotes one support securing sheave provided on the lower flange plate 22 of the inner cylinder 21 of the first stage. The support securing sheave 35 is rotatably supported by a bracket 36 fixed to the lower flange plate 22 of the inner tube 21. [

Reference numeral 37 denotes a supporting rope for supporting the inner cylinder 21 between the outer cylinder 13 and the inner cylinder 23. The supporting rope 37 is constituted by a wire rope. 9 and 10, the one end 37A of the support rope 37 is engaged with the lower flange plate 15 of the outer tube 13, and in the middle of the support rope 37 The portion is wound around the support securing sheave 35. The other end 37B of the support rope 37 is inserted into the inner tube 21 from the support securing sheave 35 and is inserted from the inner side of the inner tube 21 to the upper side of the inner tube 23 It has been locked.

Next, a pushing mechanism 38 for pushing the inner cylinder 21 in the stretching direction when the inner cylinder 21 is extended from the outer cylinder 13 by the stretching and shrinking cylinder 25 will be described.

38 shows a pushing mechanism provided between the outer cylinder 13 and the inner cylinder 21 of the first stage and the pushing mechanism 38 is configured such that the inner cylinder 21 is connected to the outer cylinder 13 , The inner tube 21 is maintained in a stretched state.

The pushing mechanism 38 is composed of a pushing sheave 39 for pushing, a movable sheave 41 for pushing, and a pushing rope 42, Two sets are provided so as to be symmetrical in the left and right directions with the cylinder 25 therebetween, and they have the same structure. For this reason, the pushing mechanism 38 arranged on the left side of the outer cylinder 13 will be described below, and the elements arranged on the right side are denoted by the same reference numerals " " .

And reference numeral 39 denotes one pushing sheave for pushing installed on the lower side of the outer cylinder 13. [ 14, the pushing securing sheave 39 pushes the support shaft 39A against the bracket 40 fixed to the outer cylinder 13 over the sheave attachment opening 16 formed in the outer cylinder 13, And is rotatably supported. In this case, the support shaft 39A of the pushing sheave 39 for pushing is disposed at an inclined angle of the angle? With respect to the left side face 13C of the outer cylinder 13. That is, the support shaft 39A of the pushing sheave 39 for pushing is disposed non-parallel to the rear surface 13A of the outer cylinder 13, and is fixed to the pushing sheave 39 for pushing supported by the support shaft 39A Is partially housed inside the outer cylinder 13. The outer cylinder 13 is formed of a resin.

And reference numeral 41 denotes a pushing movable sheave provided on the sheave mounting opening 29 at a position lower than the movable sheave 33 for expansion and contraction. As shown in Fig. 13, the pushing movable sheave 41 is rotatably supported on the lower sheave support portion 29C of the sheave mounting hole 29 via a support shaft 41A. In this case, the support shaft 41A of the pushing movable sheave 41 is arranged parallel to the rear surface 13A of the outer tube 13. [ The pushing movable sheave 41 is moved toward or away from the pushing fixed sheave 39 by moving the sheave attaching opening 29 upward and downward as the expanding and contracting cylinder 25 expands and shrinks .

Reference numeral 42 denotes a pushing rope connecting the outer tube 13 and the inner tube 21, and the pushing rope 42 is constituted by a wire rope. 9 and 10, the one end side 42A of the pushing rope 42 is engaged with the upper flange plate 14 of the outer tube 13 and the pushing rope 42 is engaged with the pushing rope 42, Is wound around the pushing movable sheave 41 and the pushing sheave 39 for pushing. The other end side 42B of the pushing rope 42 is inserted from the pushing sheave 39 for pushing into the inside of the outer cylinder 13 and the inner side of the inner cylinder 21 Respectively.

1 and 9, the tube 25A of the extensible cylinder 25 is moved upward together with the sheave mounting hole 29, and the tube 25A of the extensible cylinder 25 is moved upward The movable sheave 33 approaches the fixed sheave 31 for expansion and contraction. The expansion and contraction rope 34 wound on the movable sheave 33 for expansion and contraction and the fixed sheave 31 for expansion and contraction are released and the inner cylinder 23 extends downward from the outer cylinder 13 by its own weight. At this time, since the other end side 37B of the support rope 37 engaged with the upper side of the inner cylinder 23 moves downward together with the inner cylinder 23, the inner cylinder 21 supported by the support rope 37, And extends downward from the outer cylinder 13 by self weight. Thus, as shown in Figs. 2 and 10, the tube 25A is moved to the upper limit position and the extensible cylinder 25 reaches the minimized state, so that the extensible arm 12 is in the latest state.

When the sheave mount 29 approaches the retractable securing sheave 31, the pushing rope 42 is wound between the pushing movable sheave 41 and the pushing sheave 39 for pushing, And the other end side 42B of the pushing rope 42 moves downward along the inner tube 21. [ As a result, the pushing rope 42 always maintains a constant tension. Further, since the inner tube 21 is stretched while being supported by the support rope 37, the support rope 37 always maintains a constant tension.

Therefore, in the state where the inner cylinders 21 and 23 are extended from the outer cylinder 13, excavation work is performed using the clam shell bucket 43 described later, whereby an upward excavating reaction force acts on the inner cylinders 21 and 23 It is possible to suppress the movement of the inner tubes 21 and 23 to the reduction side due to the tension of the pushing rope 42 and the support rope 37. [

2 and 10, the tube 25A of the extensible cylinder 25 is moved downward together with the sheave attachment port 29, and the tube 25A of the extensible cylinder 25 is moved downward together with the sheave attachment port 29, The movable sheave 33 for expansion and contraction is separated from the fixed sheave 31 for expansion and contraction. As a result, the stretch rope 34 is wound between the movable sheave 33 for expansion and contraction and the fixed sheave 31 for expansion and contraction, and the inner cylinder 23 moves upward and is accommodated in the inner cylinder 21. [ At this time, since the other end side 37B of the support rope 37 engaged with the upper side of the inner cylinder 23 moves upward together with the inner cylinder 23, the inner cylinder 21 supported by the support rope 37, So that it is accommodated in the outer cylinder 13. Thus, as shown in Figs. 1 and 9, the tube 25A moves to the lower limit position and the extensible cylinder 25 reaches the latest length state, so that the extensible arm 12 is in the minimized state.

On the other hand, when the telescopic arm 12 is stretched or shrunk between the minimized state and the latest state, the telescopic cylinder is provided with a telescoping sheave 31 'disposed on the right side of the telescopic cylinder 25, The push rope 34 ', the supporting sheave 35', the supporting rope 37 ', the pushing sheave 39' for pushing, and the pushing mechanism 38 ' The loading movable sheave 41 'and the pushing rope 42' also operate in the same manner as described above.

Here, as shown in Figs. 13 and 14, the outer cylinder 13 is supported by the rear surface 13A, the front surface 13B, the left and right side surfaces 13C and 13D and the left and right oblique surfaces 13E and 13F And the pushing movable sheave 41 is arranged at a position facing the left-side slope 13E in the left-right direction. Therefore, as shown by the arrow X in FIG. 13, the pushing movable sheave 41 can be arranged close to the left-side slope 13E, and preferably the left and right sides 13C and 13D and It may be installed at an equal position or at a more inner position. The supporting shaft 39A of the pushing sheave 39 for pushing the pushing rope 42 between the support sheave 41 and the pushing movable sheave 41 and the left side surface 13C of the outer tube 13 The portion of the pushing sheave 39 for pushing which is accommodated in the outer cylinder 13 can be sufficiently separated from the inner cylinder 21 as indicated by the arrow Y in Fig. 14 The amount of protrusion of the portion of the pushing sheave 39 for pushing the outside from the outer cylinder 13 from the left and right side faces 13C and 13D of the outer cylinder 13 can be reduced. As a result, without increasing the dimension between the left and right side surfaces 13C and 13D of the outer tube 13, a sufficient gap is secured between the pushing fixed sheave 39 and the inner tube 21 so that they do not interfere with each other The entire stretchable arm 12 can be made compact. This also applies to the pushing movable sheave 41 'and the pushing rope 42' disposed on the right side with the extensible cylinder 25 in between.

Reference numeral 43 denotes a clam shell bucket which is mounted on the mounting eye 24 provided on the front end side (lower end side) of the inner cylinder 23 so as to be swingable. The clam shell bucket 43 is opened and closed by expanding and contracting the bucket cylinder 44 to excavate the gravel.

The deep drawing excavator 1 according to the present embodiment has the structure described above and will hereinafter be described with reference to a work for excavating the vertical arcs 101 by using the deep drawing excavator 1 with respect to the ground drawing surface 100 do. The hydraulic circuit for stretching and contracting the extensible cylinder 25 will be described in detail later.

First, as shown in Fig. 1, the deep drawing excavator 1 has a construction in which the expansion / contraction cylinder 25 is latest placed to bring the expansion / contraction arm 12 into a state of minimization, Thereby holding the telescopic arm 12 in a vertical posture.

In this state, the tube 25A of the stretching and shrinking cylinder 25 is moved upward together with the sheave mounting opening 29 by contracting the stretching and shrinking cylinder 25, 31). This causes the expansion and contraction rope 34 wound on the movable sheave 33 for expansion and contraction and the fixed sheave 31 for expansion and contraction to be released and the inner cylinder 23 to extend downward from the outer cylinder 13 by its own weight The inner tube 21 supported by the support rope 37 also extends downward from the outer tube 13 by its own weight.

At this time, the pushing rope 42 is wound between the pushing movable sheave 41 supported by the sheave mount 29 and the pushing sheave 39 for pushing, Always maintain a constant tension. The support rope 37 that supports the inner tube 21 between the outer tube 13 and the inner tube 23 also maintains a constant tension at all times.

As a result, the inner cylinders 21, 23 can be maintained in a stretched state from the outer cylinder 13 by the tension of the push rope 42 and the support rope 37, (Not shown). In this state, by opening and closing the clam shell bucket 43 by the bucket cylinder 44, the clam shell bucket 43 can be used to deeply drill the vertical shaft 101, It is possible to leave a large amount of soil.

The tube 25A of the stretching and shrinking cylinder 25 is moved downward together with the sheave mounting opening 29 by stretching the stretching and contracting cylinder 25 after the clay shell bucket 43 releases the gravel, The sheave 33 is separated from the fixed sheave 31 for expansion and contraction.

As a result, the stretch rope 34 is wound between the movable sheave 33 for expansion and contraction and the fixed sheave 31 for expansion and contraction, and the inner cylinder 23 moves upward and is accommodated in the inner cylinder 21. [ At this time, the other end side 37B of the support rope 37 connecting between the outer cylinder 13 and the inner cylinder 23 is moved upward together with the inner cylinder 23 to be supported by the support rope 37 The inner cylinder 21 also moves upward and is accommodated in the outer cylinder 13.

1, after the extensible cylinder 25 reaches the latest length state and the extensible arm 12 is brought into the minimized state, the distal end side of the boom 4 is lifted up and the clamshell bucket 43 is lifted up, Is extracted from the vertical shaft (101). Then, the soil is held frequently by the lower traveling body 2 to a desired soil site, and then the soil held by the clamshell bucket 43 is discharged to the soil site.

Here, in the deep groove excavator 1 according to the present embodiment, the distal end portion 25C of the rod 25B of the extensible cylinder 25 is fixed to the bracket 13J provided on the outer cylinder 13 of the expansion arm 12 And a sheave mounting hole 29 for supporting the movable sheave 33 for expansion and contraction is mounted on the free end tube 25A. Therefore, when the stretchable cylinder 25 is stretched to shrink the stretchable arm 12 in order to lift up the gravel excavated by the clam shell bucket 43 onto the ground, the tube 25A, which is a heavy material, (29) move together downward. As a result, a downward load due to the weight of the tube 25A and the sheave mounting hole 29 acts on the stretch rope 34 wound around the movable sheave 33 for expansion and contraction and the sheave 31 for expansion and contraction do. As a result, the pulling force of the inner cylinders 21 and 23 can be increased by using the weight of the tube 25A and the sheave mount 29, and the pulling action of the inner cylinders 21 and 23 by the extensible cylinder 25 Can be efficiently performed.

The digging excavator 1 according to the present embodiment is constituted by the two fixed sheaves 31A and 31B and the movable sheave 33 for expansion and contraction And the stretch ropes 34 are constituted by the movable sheaves 33A and 33B so as to be wound around the two fixed sheaves 31A and 31B and the two movable sheaves 33A and 33B four times . As a result, for example, as compared with the construction in which the rope for extension and contraction is wound eight times between four pieces of the fixed sheave for expansion and contraction and the movable sheave for extension and contraction, as in the prior art, .

In addition, between the two fixed sheaves 31A and 31B constituting the fixed sheave 31 for expansion and contraction and the two movable sheaves 33A and 33B constituting the movable sheave 33 for expansion and contraction, The lifting amount when the inner tubes 21 and 23 are lifted by using the stretching rope 34 can be made four times as large as the stroke of the stretching and contracting cylinder 25 by winding the inner tube 34 , 23 can be efficiently pulled up.

In the present embodiment, the rod 25B of the extensible cylinder 25 is fixed to the upper side of the outer cylinder 13 and below the fixed sheave 31 for expansion and contraction. This makes it possible to move the tube 25A of the extensible cylinder 25 on which the sheave mountings 29 are mounted in the upward and downward directions in the range of substantially the upper half of the outer cylinder 13 extending in the upward and downward directions . 1, the operator in the cap 3B of the upper revolving structure 3 can be moved in the direction of the axis of the elongated shaft 3 in the direction of the axis of the elongated shaft 3, The expansion and contraction operations of the cylinder 25 can be visually confirmed, and workability and safety of the excavation work can be enhanced.

In the present embodiment, two sheave mounting hole guide rails 27 extending in the longitudinal direction in parallel with the outer cylinder 13 are fixed and installed on the outer side of the outer cylinder 13, and the sheave mounting holes 29 And moves in the longitudinal direction of the outer cylinder 13 along the sheave mounting port guide rail 27 as the expansion and contraction cylinder 25 expands and shrinks.

Therefore, the sheave mount 29 is guided by the sheave mount guide rail 27 and can always move on a constant orbit. As a result, the stretch rope 34 wound around the telescopic sheave 31 and the telescopic sheave 33 can smoothly follow the movement of the telescopic sheave 33, The stability of the expansion and contraction operation of the inner tubes 21 and 23 can be enhanced. In addition, since the strength of the outer cylinder 13 can be increased by the two sheave mounting port guide rails 27 fixed to the outer cylinder 13, the reliability of the entire stretchable arm 12 can be enhanced.

On the other hand, the tube 25A of the extensible cylinder 25, on which the sheave mount 29 is mounted, can also move on a constant orbit along the sheave mount guide rail 27. As a result, it is possible to increase the strength against the buckling and the lateral load of the stretching and shrinking cylinder 25, thereby enhancing the reliability of the stretching and contracting cylinder 25.

In the present embodiment, a pair of boom brackets 17 are provided on the rear surface 13A of the outer tub 13 located on the cab 3B side of the upper turn body 3, The bracket 17 is mounted on the end side of the boom 4 and the extensible cylinder 25 is disposed in the gap 17B formed between the boom brackets 17.

The sheave mount 29 attached to the tube 25A of the extensible cylinder 25, the movable sheave 33 for expansion and contraction supported by the sheave mount 29, the fixed sheave 31 for expansion and contraction, The rope 34 and the like that are wound around the movable sheave 33 can be seen directly from the side of the cap 3B of the upper revolving structure 3. [ This allows the operator in the cap 3B to expand and contract the inner cylinders 21 and 23 relative to the outer cylinder 13 while visually observing the extensible cylinder 25 or the like.

The extension cylinder 25, the fixed sheave 31 for expansion and contraction, the sheave attachment hole 29, and the sheave attachment hole 29 are provided on the front surface 13B of the outer tube 13 opposite to the rear surface 13A where the boom bracket 17 is provided. It is not necessary to provide the movable sheave 33 for expansion and contraction. Therefore, during the excavation of the vertical shaft 101, these extensible cylinders 25 and the like are prevented from coming into contact with the obstacle and are not damaged, and workability of excavation work can be enhanced.

On the other hand, as shown in Fig. 15, when the front surface 13B on the opposite side to the rear surface 13A mounted on the boom 4 in the outer cylinder 13 is placed on the ground to make the deep excavator 1 in the transportation posture The movable sheave 33 and the like for stretching and shrinking can be used as the stretchable cylinder 25, the sheave attaching member 29, the retracting fixed sheave 31 and the stretchable and movable sheave 33 without using a special stand or the like It can be maintained in an upward posture.

Therefore, in the state in which the deep drawing excavator 1 is in the transporting posture, the extensible cylinder 25, the fixed sheave 31 for expansion and contraction, the sheave mounting hole 29, the movable sheave 33 for expansion and contraction, Etc. can be performed at a position close to the ground, and the workability of this maintenance work can be enhanced.

In this embodiment, a square tube guide 26 is provided on the rear face 13A of the outer cylinder 13 and the tube 25A of the extensible cylinder 25 is moved ). As a result, the tube 25A of the extensible cylinder 25 as a free end can be guided in the longitudinal direction of the outer tube 13 by the tube guide 26, 25A can be smoothly moved.

In addition, since the tube 25A of the extensible cylinder 25 can move along a predetermined orbit along the tube guide 26, the strength of the extensible cylinder 25 against buckling or lateral load can be increased. In addition, the tube 25A can be protected from falling stones or the like due to excavation work of the vertical shaft 101 by accommodating the tube 25A in the tube guide 26. [

In the present embodiment, the outer cylinder 13 is formed in a cylindrical shape having a hexagonal cross-sectional shape, and is arranged between the rear face 13A mounted on the front end side of the boom 4 and the left and right side faces 13C and 13D And left and right slant surfaces 13E and 13F are provided. As a result, the buckling strength can be increased with respect to the load acting on the outer cylinder 13 and the life of the outer cylinder 13 can be prolonged, so that the reliability of the entire stretchable arm 12 can be enhanced.

The movable sheave 33 for expansion and contraction is disposed on the outer side of the left side face 13C of the outer cylinder 13 so that the movable sheave 33 for expansion and contraction is slightly spaced from the left side face 13C of the outer cylinder 13 And face to face in the left and right directions. This makes it possible to prevent the movable sheave 33 for extension and contraction from projecting greatly toward the rear surface 13A side of the outer cylinder 13. Even when the expandable movable sheave 33 having a large diameter is used, The periphery of the sheave 33 can be downsized. As a result, the life of the stretch rope 34 can be prolonged by using the stretchable movable sheave 33 having a large diameter.

As described above, since the deep drawing excavator 1 according to the present embodiment has a structure capable of extending the life of the stretch rope 34, the load acting on the stretch rope 34 can be set large. As a result, the capacity of the clamshell bucket 43 mounted on the tip end side of the inner cylinder 23 to which the rope for extension and contraction is connected can be increased, and the digging efficiency can be increased by digging a large amount of gravel.

The shim excavator 1 according to the present embodiment is provided with the sheave mounting opening 16 on the lower side of the outer cylinder 13 and part of the pushing sheave 39 for pushing the sheave mounting opening 16 And is disposed on the inner side of the outer cylinder 13. Therefore, even when the diameter of the pushing sheave 39 for pushing is set to be large, the pushing sheave 39 for pushing can be mounted compactly on the outer cylinder 13. As a result, the life of the push rope 42 can be prolonged by using the push-in securing sheave 39 with a large diameter.

Further, by disposing the pushing sheave 39 for pushing at the position of the sheave attaching opening 16 provided at the lower side of the outer cylinder 13, it is necessary to arrange the pushing sheave for pushing in the lower end portion of the outer cylinder as in the prior art There is no. This prevents the lower flange plate 22 provided at the lower end portion of the inner tube 21 from interfering with the pushing sheave 39 for pushing when the inner tube 21 is housed in the outer tube 13, 21 can be brought close to the vicinity of the lower end portion 13H of the outer cylinder 13. [ As a result, the entire length of the telescopic arm 12 when the telescopic arm 12 is minimized can be shortened. For example, a compact telescopic attitude can be achieved when the deep-drawn excavator 1 is transported.

In the above-described embodiment, the outer cylinder 13 constituting the stretchable arm 12 is provided with the extensible cylinder 25, the sheave mounting hole guide rail 27 A sheave mount 29, a fixed sheave 31 for expansion and contraction, a movable sheave 33 for expansion and contraction, and the like are arranged. However, the present invention is not limited to this. For example, as shown in the modification shown in Fig. 16, the front face 13B, which is the opposite side of the rear face 13A on which the boom bracket 17 is mounted, A sheave mounting guide rail 27, a sheave mounting hole 29, a fixed sheave 31 for expansion and contraction, a movable sheave 33 for expansion and contraction, and the like may be disposed. As a result, the operator who is accustomed to the existing telescopic arm has no discomfort when the digging excavator is operated, and the operability thereof can be enhanced.

In the above-described embodiment, the movable sheaves 33 and 33 ', the stretching ropes 34 and 34', the supporting sheaves 35 and 35 'for stretching and shrinking, The supporting ropes 37 and 37 ', the pushing sheaves 39 and 39', the pushing movable sheaves 41 and 41 ', and the pushing ropes 42 and 42' , And two sets of the outer cylinder 13 are provided so as to be symmetrical with respect to the left and right with the extensible cylinder 25 therebetween. However, the present invention is not limited to this, and the present invention is not limited to this, and may be applied to a case in which the fixed sheave 31 for expansion and contraction, the movable sheave 33 for expansion and contraction, the stretching rope 34, the fixed sheave for support 35, It is also possible to provide a constitution in which one set of the respective members such as the fixed sheave 39 for pushing, the movable sheave 41 for pushing, the pushing rope 42 and the like are provided at the central portion in the left and right direction of the outer cylinder 13.

--- About hydraulic circuit ---

The hydraulic circuit for stretching and contracting the extensible cylinder 25 will be described below. 17 shows an overall configuration of a hydraulic device 300 including a schematic configuration of a hydraulic circuit 200 of the present embodiment and a multi-stage arm driving mechanism 111 whose expansion and contraction is controlled by the hydraulic circuit 200 FIG. 17, for the sake of convenience, the above-described multi-stage arm driving mechanism, that is, the extensible cylinder 25, the sheave mount 29, the fixed sheave 31 for expansion and contraction, And the rope 34 for expansion and contraction are omitted and partially omitted.

The hydraulic circuit 200 includes a hydraulic pump 201, a control valve 210, a first flow path 241, a second flow path 242, a counterbalance valve 221, a relief valve 222, A switching valve 232, and a slow return valve 231 having a variable throttle.

The control valve 210 is a control valve for controlling the flow of pressure oil from the hydraulic pump 201 to the extensible cylinder 25 and the position and amount of movement of the spool are changed based on the operation of the operation member . In this embodiment, the control valve 210 is a hydraulic pilot operated control valve, and based on the pilot pressure oil pressure supplied by the pilot pipes 261 and 262 in accordance with the operation of the operating member, Is changed. Examples of the operating member include an operation lever, an operation pedal, and the like. The control valve 210 is switched to a contracted position (a position) for contracting the extensible cylinder 25 based on the pressure of the pilot pressure supplied by the pilot line 261 and supplied to the pilot line 262 (B position) in which the expansion cylinder 25 is extended, and the supply of the pilot pressure oil to the pilot pipes 261 and 262 is stopped, based on the pilot pressure of the pilot pressure in the expansion cylinder 25 (C position) for inhibiting the supply of the pressure oil and the return of the pressure oil from the expansion cylinder 25.

The extensible cylinder 25 and the control valve 210 are connected via a first flow path 241 and a second flow path 242. The first flow path 241 is a first flow path between the extensible cylinder 25 and the control valve 210 and is connected to the bottom side oil chamber 251 of the extensible cylinder 25. The second flow path 242 is a second flow path between the extensible cylinder 25 and the control valve 210 and is connected to the rod side oil chamber 252 of the extensible cylinder 25. The control valve 210 and the working oil tank 202 are connected by a flow path 245. The second oil passage 242 is connected to oil passages 243 and 244 for guiding the pressure oil of the second oil passage 242 to the hydraulic oil tank 202 without passing through the control valve 210. [ In the present embodiment, the piping that leads to the hydraulic oil tank 202, that is, the hydraulic pressure circuit that becomes the pressure of the tank, is referred to as the low-pressure side of the hydraulic circuit 200.

The counterbalance valve 221 is provided in the first flow path 241. The counterbalance valve 221 incorporates a check valve 221a and permits the flow of pressure oil toward the bottom side chamber 251 of the extensible cylinder 25. The pilot port of the counterbalance valve 221 is connected to the second flow path 242 by the pilot flow path 221p and the counterbalance valve 221 is connected to the second flow path 242 The valve is opened. The relief valve 222 has a primary port 222a connected to the flow path between the bottom side chamber 251 and the counterbalance valve 221 of the first flow path 241 and a second port 242 connected to the second flow path 242 And the second port 222b is connected. The counterbalance valve 221 and the relief valve 222 are integrally provided as a valve block 220 so that the bottom side oil chamber 251 and the rod side oil chamber 252 of the extensible cylinder 25 As shown in Fig.

The switching valve 232 is provided between the oil line 243 and the oil line 244 and is switched by the pilot oil supplied to the pilot line 261 so that the oil line 243 and the oil line 244 It is a hydraulic pilot operated switching valve that connects / disconnects. The switching valve 232 is connected to a permitting position (a position) permitting the pressure oil of the second flow path 242 to flow to the low pressure side of the hydraulic circuit 200 and to a low pressure side of the hydraulic circuit 200, (B position) for inhibiting the flow of the pressurized oil from the pressurizing chamber 242 is prohibited. The flow path 243 is a flow path for connecting the second flow path 242 to the switching valve 232 and the flow path 244 is a flow path for connecting the switching valve 232 and the working oil tank 202, Pressure side of the circuit (200).

The slow return valve 231 having the variable throttle is provided in the flow path between the counterbalance valve 221 and the control valve 210 in the first flow path 241. That is, the slow return valve 231 having the variable throttle is installed in series with the counterbalance valve 221 and the control valve 210. Since the slow return valve 231 having the variable throttle incorporates the check valve 223a, the flow rate is not controlled for the pressure to the bottom side chamber 251 of the extensible cylinder 25.

--- Stretching and stopping of the stretching arm 12 ---

Next, the operation of the hydraulic circuit 200 will be described. The pilot pressure oil is not supplied to the pilot pipes 261 and 262 when the operation member (not shown) of the operator is not operated. As a result, the control valve 210 is switched to the position c. Therefore, the control valve 210 blocks the pressure oil from the hydraulic pump 201 so that the pressurized oil from the hydraulic pump 201 is not supplied to the bottom side oil chamber 251 and the rod side oil chamber 252, The oil returning from the side oil chamber 251 and the rod side oil chamber 252 to the tank 202 via the oil passage 245 is blocked.

The pressurized oil of the bottom side oil chamber 251 is blocked by the counterbalance valve 221 and the control valve 210 so as not to flow out to the oil line connected to the low pressure side of the oil line 244 or the oil line 245, .

Since the pilot pressure oil is not supplied to the pilot pipe 261, the switch valve 232 is switched to the a position by the biasing force of the built-in spring. The second flow path 242 is shut off from the flow path 245 by the control valve 210. The second flow path 242 is connected to the low pressure side via the flow path 243, the switching valve 232, (Not shown).

The rod 25B is contracted by the self weight of the inner shells 21 and 23 of the telescopic arm 12 and the clam shell bucket 43 mounted on the lower end of the inner cylinder 23 Load is acting. Therefore, the pressure oil of the bottom side oil chamber 251 is compressed via the piston 25E. However, as described above, the bottom side oil chamber 251 is blocked by the counterbalance valve 221 from the oil passage on the low pressure side. Therefore, when the operating member (not shown) is not operated by the operator, the inner tubes 21, 23 and the clamshell bucket 43 of the telescopic arm 12 stop against gravity.

When the excavator 11 is raised by driving the above-described boom cylinder 4A or excavator rocking cylinder 4B while the expansion and contraction of the expansion and contraction arm 12 is stopped, the clam shell bucket 43 (Downward direction) acts on the telescopic arm 12 at the time of detaching it from the ground. Therefore, when the clam shell bucket 43 is detached from the ground, a large pressure acts on the bottom side oil chamber 251. However, in the present embodiment, as described above, the primary port 222a of the relief valve 222 is connected to the flow path between the bottom side oil chamber 251 and the counterbalance valve 221, and the second flow path 242 And the secondary side port 222b is connected to the secondary side port 222b. Therefore, even if the pressure in the bottom side oil chamber 251 rises, the relief valve 222 allows the high pressure fluid to flow to the second flow path 242. The pressure oil flowing from the bottom side oil chamber 251 to the second flow path 242 through the relief valve 222 is supplied to the hydraulic circuit 200 via the oil path 243, the switching valve 232, Pressure side.

--- Extension of the telescopic arm 12 ---

When an operation member (not shown) is operated by the operator to extend the telescopic arm 12, that is, to retract the telescopic cylinder 25, a pilot pressure oil of a pressure corresponding to the operation amount of the operating member is supplied to the pilot pipe 261 do. As a result, the control valve 210 is switched to the a position and the switching valve 232 is switched to the b position. The pressurized oil from the hydraulic pump 201 does not flow to the low pressure side of the hydraulic circuit 200 through the switching valve 232 and is supplied to the rod side oil chamber 252 via the second flow path 242. [

The pressure oil from the hydraulic pump 201 flows to the second flow path 242 so that the pressure oil from the hydraulic pump 201 is supplied to the counterbalance valve 221 via the flow path 221p connected to the second flow path 242, As a pilot pressure. The counterbalance valve 221 is opened and the pressure oil in the bottom side oil chamber 251 is supplied to the variable throttle valve 251 via the counterbalance valve 221, To the slow return valve 231, which is provided with a check valve. The expansion and contraction cylinder 25 can be smoothly started without being affected by the weight of the inner shells 21 and 23 of the expansion and contraction arm 12 and the clam shell bucket 43 and the like.

Since the control valve 210 is switched to the position a, the first flow path 241 is connected to the flow path 245 via the control valve 210. The pressure of the bottom side oil chamber 251 is controlled by the slow return valve 231 having the variable throttle via the counterbalance valve 221 and flows out to the low pressure side of the hydraulic circuit 200 .

In this embodiment, the speed at the time of extension is increased by using a dynamic pulley as the multi-stage stretching arm driving mechanism 111. [ Thus, the operator can adjust the variable throttling amount of the slow return valve 231 having the variable throttle to select the desired arm extension speed.

Therefore, when the operation member (not shown) is operated by the operator so that the expansion and contraction arm 12 is extended, that is, the expansion and contraction cylinder 25 is contracted, the compression oil supplied to the rod- And the stretching arm 12 is stretched.

--- contraction of the stretching arm 12 ---

When the operating member (not shown) is operated by the operator so that the expansion and contraction arm 12 is contracted, that is, the expansion cylinder 25 is extended, the pilot pressure oil of the pressure corresponding to the operation amount of the operating member is supplied to the pilot pipe 262 do. As a result, the control valve 210 is switched to the position b. Therefore, the pressure oil from the hydraulic pump 201 is supplied to the backflow prevention valve 231a built in the slow return valve 231 having the variable throttle of the first flow path 241 and the back flow prevention valve 231a built in the counter balance valve 221 And is supplied to the bottom side oil chamber 251 through the valve 221a.

Since the pilot pressure oil is not supplied to the pilot pipe 261, the switch valve 232 is switched to the a position by the biasing force of the built-in spring. Further, as described above, the control valve 210 is switched to the b position. Therefore, the second flow path 242 is connected to the tank 202 via the control valve 210 and the flow path 245, and the flow path 243, the switching valve 232, And is connected to the tank 202. This allows the pressure oil in the rod side oil chamber 252 to flow to the low pressure side of the hydraulic circuit 200 via the control valve 210 and the switching valve 232. The hydraulic fluid in the rod side oil chamber 252 is supplied to the hydraulic circuit 200 via the switching valve 232 without being affected by the back pressure by the control valve 210 Pressure side.

Therefore, when the operation member (not shown) is operated by the operator so that the expansion and contraction arm 12 contracts, that is, the expansion and contraction cylinder 25 is stretched, the compression oil supplied to the bottom side oil chamber 251 causes the expansion cylinder 25 And the telescopic arm 12 is contracted.

Even if the pressure in the bottom side oil chamber 251 rises more than necessary when the clam shell bucket 43 is raised from the ground by shrinking the telescopic arm 12, (242).

The hydraulic circuit 200 and the hydraulic device 300 of the present embodiment have the following operational effects.

(1) A counterbalance valve 221 is provided in the first flow path 241 connected to the bottom side oil chamber 251 of the extensible cylinder 25. The primary side port 222a of the relief valve 222 is connected to the flow path between the bottom side oil chamber 251 and the counterbalance valve 221 in the first flow path 241 and the relief valve 222 is connected to the second flow path 242, And the secondary port 222b of the secondary battery 222 is connected. In addition, the switching valve 232 is provided in the flow path 243 branching from the second flow path 242.

That is, the pressure oil of the bottom side oil chamber 251 is blocked by the counterbalance valve 221 and the control valve 210 having the neutral position (position c). Therefore, even if there is a problem in the first flow path 241 between the counterbalance valve 221 and the control valve 210, for example, the pressure oil of the bottom side oil chamber 251 can be held by the counterbalance valve 221 . Further, even if a problem occurs in the counterbalance valve 221, for example, the pressure oil of the bottom side oil chamber 251 can be held by the control valve 210 at the neutral position (position c). As a result, the expansion and contraction arm 12 and the clamshell bucket 43 mounted on the lower end side of the telescopic arm 12 can be held against gravity to improve the reliability of the deep groove excavator 1.

The switching valve 232 is switched to the position b when the expandable arm 12 is extended, that is, when the expandable cylinder 25 is contracted. This allows the pressure oil from the hydraulic pump 201 to flow to the low pressure side of the hydraulic circuit 200 via the switching valve 232 at the time of extension of the expansion and contraction arm 12, And is supplied to the rod-side oil chamber 252 via the second flow path 242. Further, the switching valve 232 is configured to be switched to the position a when the expandable arm 12 is contracted, that is, when the expandable cylinder 25 is extended. This prevents the pressure oil in the rod side oil chamber 252 from being influenced by the switching valve 232 without being affected by the back pressure by the control valve 210 at the time of extension of the expansion and contraction arm 12, Pressure side of the hydraulic circuit 200 via the oil passage. Therefore, the back pressure acting on the pressure in the rod-side oil chamber 252 can be reduced at the time of stretching of the telescopic arm 12 without adversely affecting elongation of the telescopic arm 12, The efficiency can be improved and the energy efficiency of the deep drawing excavator 1 can be improved.

The pressure oil flows from the relief valve 222 to the second flow path 242 even if the pressure in the bottom side oil chamber 251 rises. Therefore, when the clam shell bucket 43 is raised in the ground by, for example, raising the excavating apparatus 11 by the boom lifting operation or contracting the stretching arm 12, the pressure in the bottom side oil chamber 251 Can be suppressed. Therefore, the durability of the extensible cylinder 25 and the counterbalance valve 221 can be improved, so that the durability and reliability of the deep groove excavator 1 can be improved.

(2) In the first flow path 241, a slow return valve 231 having a variable throttle is provided in the flow path between the counterbalance valve 221 and the control valve 210. Therefore, the elongation speed of the elongating and contracting arm 12, that is, the contracting speed of the elongating and contracting cylinder 25 can be set arbitrarily. For example, by setting the operator at a desired speed, the operability and working efficiency of the deep drawing excavator 1 can be improved can do. Further, even if a problem occurs in the counterbalance valve 221, for example, the flow rate of pressurized oil in the slow return valve 231 having a variable throttle is reduced and the elongation speed of the stretchable arm 12 is suppressed, The reliability of the deep excavator 1 can be improved.

(3) Since the configuration of the hydraulic circuit 200 is simple and each of the functions described above can be efficiently exhibited, the manufacturing cost of the hydraulic circuit 200 can be suppressed and the reliability of the hydraulic circuit 200 can be improved can do. Also, the maintenance cost of the hydraulic circuit 200 can be suppressed. Therefore, the manufacturing cost and the running cost of the deep drawing excavator 1 can be suppressed, and the reliability can be improved.

In the above description, the pressure oil from the hydraulic pump 201 acts as the pilot pressure to the counterbalance valve 221 through the oil passage 221p branching from the second oil passage 242. However, But is not limited thereto. The pilot pressure oil supplied to the pilot pipe 261 is supplied to the counterbalance valve 221 via the pilot valve 261 by operating the unillustrated operating member so that the expansion and contraction arm 12 is extended, It may be configured to act as a pressure.

In the above description, the control valve 210 and the switching valve 232 are hydraulic pilot operated valves, but the present invention is not limited thereto. For example, the control valve 210 and the switching valve 232 may be electromagnetically operated valves. In this case, the operation signal may be input to the switch valve 232 so that the switch valve 232 is switched to the b position by the operation signal for switching the control valve 210 to the a position.

In the above description, the setting operation of the slow return valve 231 having a variable throttle is not specifically mentioned. For example, the setting operation may be performed from within the cap 3B, It is also possible to perform the setting operation at the arrangement position of the slow return valve 231 having the opening.

Further, in the present invention, it is not essential to provide a slow return valve 231 having a variable throttle, and a slow return valve having a fixed throttle may be used. Further, the slow return valve 231 having a variable throttle need not be provided. The above-described embodiments and modifications may be combined with each other.

In addition, the present invention is not limited to the above-described embodiment, but may be applied to a multi-stage arm driving mechanism that shrinks the multi-stage arm by extension of the hydraulic cylinder and extends the multi- A hydraulic device of a multistage arm of various structures provided with a hydraulic circuit for contracting and a hydraulic excavator of various structures including the hydraulic device of the multi-stage arm. In order to control the flow of pressure oil to the hydraulic cylinder, the hydraulic circuit inhibits the extension of the hydraulic cylinder, the contraction position of the hydraulic cylinder to contract, and the supply of pressure to the hydraulic cylinder and the return of the pressure from the hydraulic cylinder A second flow path between the load side chamber of the hydraulic cylinder and the control valve and a second flow path between the load side chamber of the hydraulic cylinder and the counterbalance valve installed in the first flow path, A relief valve in which a primary side is connected to a flow path between the bottom side oil chamber and the counterbalance valve and a secondary side is connected to the second flow path of the first flow path, And a prohibiting position for prohibiting the pressure oil of the second flow path from flowing to the low pressure side at the time of contraction of the hydraulic cylinder And a switching valve.

2: Lower traveling body (body)
3: Upper revolving body (body)
4: Boom
12: Multistage arm (telescopic arm)
13: outer tube
13A: Rear
13B: Front
13C: Left side
13D: Right side
13E:
13F: Right slope
13G:
13H: Lower end
16: Sheave mounting opening
17: Boom bracket
21: inner tube (outermost inner tube)
23: My heart
25: Extension cylinder
25A: tube
25B: Load
26: Tube guide
27: Sheave mounting guide rail
29: Sheave mounting hole
31, 31 ': a fixed sheave for stretching
33, 33 ': retractable movable sheave
34, 34 ': stretch rope
35, 35 ': a fixed sheave for supporting
38, 38 ': a pushing mechanism
39, 39 ': Fixing sheave for pushing
41, 41 ': a movable sheave for pushing
42, 42 ': Push-in rope
111: Multistage arm driving mechanism
200: Hydraulic circuit
210: control valve
221: Counter balance valve
222: relief valve
231: Slow return valve with variable throttle
232: Switching valve
241: First Euro
242:
300: Hydraulic device

Claims (5)

A multi-stage arm driving mechanism that shrinks the multi-stage arm by extension of the hydraulic cylinder and extends the multi-stage arm by shrinkage of the hydraulic cylinder,
And a hydraulic circuit for extending / contracting the hydraulic cylinder,
The hydraulic circuit includes:
A control unit for prohibiting an extension position for extending the hydraulic cylinder to control the flow of pressure oil to the hydraulic cylinder, a contraction position for contraction of the hydraulic cylinder, and supply of pressure oil to the hydraulic cylinder and return of the pressure cylinder from the hydraulic cylinder A control valve that is switched to a neutral position,
A first flow path between the bottom side chamber of the hydraulic cylinder and the control valve,
A second flow path between the load side chamber of the hydraulic cylinder and the control valve,
A counterbalance valve installed in the first flow path,
A relief valve having a primary side connected to a flow path between the bottom side chamber and the counterbalance valve and a secondary side connected to the second flow path,
A permitting position permitting the pressure oil of the second flow path to flow to the low pressure side when the hydraulic cylinder is extended, and a prohibiting position prohibiting the pressure oil of the second flow path from flowing to the low pressure side at the time of contraction of the hydraulic cylinder And a switching valve that is switched between the first position and the second position. The method according to claim 1,
The hydraulic circuit further comprises a slow return valve having a variable throttle provided in series with the counterbalance valve and the control valve in a flow path between the counterbalance valve and the control valve in the first flow path The hydraulic device of the multi-stage arm. The method according to claim 1,
Wherein the switching valve is switched to the permitting position when the control valve is switched to the extension position and is switched to the inhibition position when the control valve is switched to the contracting position. A boom provided so as to be able to freely move in the vehicle body; a plurality of inner cylinders provided so as to extend in the upward and downward directions on the leading end side of the boom and accommodated in the outer cylinder and the inner cylinder in such a manner as to extend and retract in the longitudinal direction, A hydraulic cylinder arranged along the longitudinal direction of the outer cylinder constituting the multi-stage arm; a fixed sheave for extension and retraction provided on the outer cylinder; and a hydraulic cylinder mounted on the hydraulic cylinder, A movable sheave for retracting and retracting, which is provided in the sheave mounting opening, and an inner cylinder whose one end is engaged with the outer cylinder and whose other end is the innermost one of the inner cylinders, , A portion of which is located at a midway point between the fixed sheave for expansion and contraction and the stretchable rope wound on the movable sheave for expansion and contraction In groups Isaac,
The hydraulic cylinder includes a tube, a rod having one side fixed to the piston in the tube and the other side projecting outward from the tube,
The rod of the hydraulic cylinder is mounted in the upper end of the rod in the upward direction and the tube of the hydraulic cylinder is made free,
The sheave mount is mounted on a tube of the hydraulic cylinder,
A deep-drawn excavator further comprising the multi-stage hydraulic device according to any one of claims 1 to 3. 5. The method of claim 4,
And the front end of the rod of the hydraulic cylinder is mounted on the upper side of the outer cylinder.

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