JPH11222847A - Soil improving machine having excavation means - Google Patents

Abstract

PROBLEM TO BE SOLVED: To keep agitation efficiency in a continuous treating tank constant even when workload of an excavation means or the like is fluctuated, and to generate improved soil having high quality extremely efficiently when the agitating and mixing means of a treating unit are driven by using a hydraulic motor for agitation operated by pressure oil from the same hydraulic pump as the driving source of the excavation means. SOLUTION: A front working mechanism is operated by using the soil improving machine, soil and sand are excavated and excavation-treatment composite works for agitating and mixing soil and sand and a soil improving material by working a hydraulic motor 28 for agitation in a continuous treating tank is conducted. The hydraulic motor 28 for agitation is connected on the priority flow path side of diversion control valves 72a, 72b constituting a flow-rate priority means 70 for surely supplying the motor 28 for agitation with pressure oil at a specified flow rate even when workload at the time of excavation is fluctuated at that time, and variable throttles 73a, 73b are mounted on the priority flow path side.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a soil improvement machine provided with an excavating means used for excavating earth and sand at a civil engineering site or a construction site, improving the soil quality of the excavated soil, and backfilling the soil. It is.

[0002]

2. Description of the Related Art Conventionally, as a method for improving a soft ground to a solid ground, there is a conventional method in which a soil improving material such as cement is mixed with the soil constituting the ground and solidified. Known from. In this method, the earth and sand that compose the ground is dug up to a predetermined depth, cement and other soil improvement materials that solidify the soil are uniformly mixed with this earth and sand, backfilled and leveled, and finally tightened. It is common practice to consolidate. This soil improvement method requires a means for excavating the earth and sand, a means for supplying the soil improvement material, a means for uniformly mixing the excavated soil and the soil improvement material, and a means for leveling and compacting. .

Here, in the soil improvement method, at least means for excavating earth and sand is required, and a hydraulic excavator is generally used as the excavating means. here,
Traveling means in a hydraulic shovel include a crawler type using a crawler belt and a wheel type having a wheel. Generally, the ground at a work site is soft and irregular on uneven terrain. Therefore, it is necessary to use a crawler type using a crawler as a traveling means in view of poor traveling conditions, the necessity of securing the stability of the vehicle body due to excavation resistance, and the like.

[0004] An improved soil is produced by supplying a soil improving material and uniformly mixing it with earth and sand. The method of producing the improved soil is roughly divided into a method of stirring and mixing using a mixing device. Conventionally, a method has been used in which a soil improving material is sprayed on the ground, and then the soil and the soil improving material are mixed by digging and stirring the soil.

[0005] The mixing apparatus includes, at a minimum, a mixing tank equipped with a stirring means and a means for supplying a soil improvement material. And earth and sand are thrown into a mixing tank, and since earth and sand excavation is performed by a hydraulic shovel, earth and sand can be thrown directly into a mixing device from this hydraulic shovel. However, since the positional relationship between the excavation position of the excavator and the arrangement position of the mixing device constantly changes, it is necessary to deposit excavated earth and sand by a hydraulic excavator at a predetermined location and to take in the accumulated sediment. Is common. Here, as this type of mixing device, for example, a device disclosed in Japanese Patent Publication No. 1-49538 is known.

[0006] This mixing device includes a sediment supply mechanism provided with a bucket for supplying sediment, a mixing tank and a supply unit for soil improvement material, and a self-propelled mixing device provided with a wheel type traveling means. The earth and sand supply mechanism is rotatable in a horizontal direction by a limited angle of the vehicle body. Furthermore, in this mixing tank, after putting a certain amount of earth and sand and a certain amount of soil improvement material, an improved soil is generated by stirring and mixing with stirring means, and discharged to a predetermined position. Processing is performed in a batch system.

[0007] On the other hand, in a method in which the soil improvement material is sprayed on the ground and mixed with the earth and sand, the soil improvement material is sprayed, and then the earth and sand are excavated to be stirred and mixed. In this case, agitation of soil and soil improvement material
Mixing can also be performed using a digging mechanism having a bucket in a hydraulic shovel, but it is difficult to uniformly stir and mix the earth and sand with the soil improvement material over a wide area, and requires a high degree of skill. Therefore, a method of stirring and mixing the soil improvement material sprayed by using the excavation mixing and stirring means with earth and sand is disclosed in, for example, Japanese Utility Model Laid-Open No. 56-733. This known excavating and mixing means has a rotor in which a number of cutters are radially connected to a rotating shaft, and can be attached to a tip of an arm connected to a boom as a front attachment in a front working mechanism of a hydraulic shovel. Has become. Then, while running the hydraulic excavator, operating the boom and the arm to press the cutter in the rotor against the ground, rotating the rotary shaft to rotate the cutter, thereby digging up the soil to improve soil quality. The material can be mixed with the earth and sand.

[0008] However, in order to obtain high quality improved soil, it is necessary to mix the earth and sand with the soil improving material as uniformly as possible. Therefore, the soil and the soil improving material are sufficiently stirred, but it is quite difficult to uniformly stir and mix the soil and the soil improving material by a method of mixing the soil and the soil improving material using a drilling and mixing means including a rotor equipped with a cutter. In addition, there is a problem that the ground cannot be improved to a deep part because of the limitation of the length of the cutter. In contrast, when a self-propelled mixing device is used, if the soil and soil improvement soil in the mixing tank are stirred for a long time by the stirring means, the soil and soil improvement material can be completely homogenized. Will be able to mix. However, in the case of a large plant where a large-capacity mixing tank is fixedly installed, the processing capacity of the mixing tank mounted on a self-propelled vehicle must be extremely low because its size is limited. Therefore, there is a problem in terms of processing efficiency in performing soil improvement at the construction site.

[0009]

In consideration of the above points,
The present applicant stirred and worked a work vehicle equipped with earth and sand excavation means.
A soil improvement machine equipped with a processing unit having a continuous processing tank having a mixing means and performing mixing in the continuous processing tank was developed, and a patent application was filed as Japanese Patent Application No. 9-156125. This soil improvement machine has a work vehicle equipped with excavating means, and thus has substantially the same configuration as a hydraulic excavator, and the processing unit is mounted on the lower traveling body side. Therefore, by moving the work vehicle, excavating the earth and sand by the excavating means, and throwing it into the continuous treatment tank, adding the soil improvement material, and operating the stirring / mixing means, the earth and sand in the tank are operated. An improved soil in which the soil improving material is uniformly mixed can be generated, and the improved soil can be backfilled at the excavation site. For this reason, the stirring / mixing means not only stirs the inside of the continuous treatment tank, but also discharges the improved soil from a portion of the continuous treatment tank where the earth and sand is charged through a portion where the soil improvement material is added. It also functions as a conveyor that transports up to.

Since the working vehicle has a function as a hydraulic excavator, the operation of the traveling, turning and excavating means is as follows.
It is driven by a hydraulic actuator composed of a hydraulic cylinder or a hydraulic motor. For this,
A hydraulic pump provided as a hydraulic source driven by the engine and a direction switching valve unit including a plurality of direction switching valves are provided. The direction switching valves constituting the direction switching valve unit are switched and operated to be provided on the work vehicle. The respective hydraulic actuators are driven.
As described above, in the continuous treatment tank, the stirring / mixing means is operated to mix the excavated soil and the soil improvement material, and the stirring / mixing means is also driven by the hydraulic motor, thereby providing the entire machine. Is simplified.

In performing soil improvement such as roadbed improvement work, it is necessary to uniformly mix excavated soil and soil improvement material. If stirring is not performed sufficiently, high quality improved soil can be obtained. Can not. However, since the continuous processing tank is installed on the lower traveling body of the work vehicle, its dimensional shape is limited by the overall length of the vehicle. Therefore, in order to uniformly mix the earth and sand with the soil improving material using a small-sized continuous processing tank, it is necessary to efficiently perform stirring by the stirring / mixing means.

By the way, since the soil is improved by the continuous treatment, the excavation work of the earth and sand and the stirring and mixing work in the tank are performed in parallel. Moreover, for excavation of earth and sand, the excavation means of earth and sand is driven by a hydraulic actuator,
The stirring and mixing means is also driven by a hydraulic actuator called a stirring hydraulic motor. Further, a common hydraulic pump is used as a hydraulic source of a hydraulic actuator composed of a hydraulic cylinder for driving the excavating means and a hydraulic source of a hydraulic motor for stirring. Then, when excavating earth and sand, since the excavation resistance acts, the work load on the hydraulic actuator on the excavation means side changes. Accordingly, when the work load increases, the discharge flow rate from the hydraulic pump decreases, which affects the operation such as a decrease in the supply flow rate to the hydraulic motor for stirring, and stabilizes the operation of the hydraulic motor for stirring. No longer. As a result, it becomes impossible to stir and mix the earth and sand in the continuous treatment tank with the soil improving material uniformly and efficiently. For this reason, in order to obtain high-quality improved soil, it is necessary to set the stirring time so that the sand and the soil improving material are evenly mixed in consideration of the fluctuation of the work load.

[0013] From the above, the above-mentioned soil improvement machine of the prior application has an excellent feature that the soil improvement can be performed easily and quickly with a small size. Due to the relationship with the quality of the improved soil, there are still unsolved problems as described above.

The present invention has been made in view of the above points, and an object of the present invention is to operate a stirring / mixing means of a processing unit by pressure oil from the same hydraulic pump as a drive source of a drilling means. In driving by using the hydraulic motor for stirring, even if the work load of the excavation means and the like fluctuates, the stirring efficiency in the continuous treatment tank can be kept constant, so that high-quality improved soil can be extremely efficiently used. Is to be able to generate it.

[0015]

In order to achieve this object, according to the present invention, an upper revolving structure is pivotally mounted on a lower traveling structure having a pair of left and right crawler tracks, and excavating means is mounted on the upper revolving structure. At least the excavating means has a hydraulically driven work vehicle operated by pressurized oil from a hydraulic pump, and the work vehicle is charged with the earth and sand excavated by the excavating means and mixed with the soil improving material. A processing unit that generates improved soil by the above-mentioned processing unit is equipped with a continuous processing tank and a hydraulic motor for stirring to mix and mix with the soil improvement material while moving excavated soil in the continuous processing tank. The stirring hydraulic motor is connected to the hydraulic pump via the flow rate priority means so as to be constant irrespective of the fluctuation of the load acting on the excavation means. It is an its features that it has a structure for supplying the hydraulic motor agitation flow.

Here, the flow priority means can be composed of a flow control valve and a throttle. The hydraulic motor for stirring is connected to the priority flow path side of the flow control valve via a control valve, and the throttle is provided between the control valve and the flow control valve. In addition, when stirring and mixing with the stirring hydraulic motor, for example, the stirring resistance changes depending on the viscosity of the injected earth and sand, and the earth and the soil improving material by stirring based on the moisture and the like contained in the earth and sand. The degree of mixing may change, and it is necessary to adjust the supply flow rate to the stirring hydraulic motor in consideration of this point. For this purpose, it is preferable that the restrictor provided on the priority flow path side is constituted by a variable restrictor so that the flow rate supplied to the hydraulic motor for stirring can be adjusted according to the properties of the soil and the like to be treated.

Driven by the stirring hydraulic motor is a stirring and mixing means for stirring the earth and sand and the soil improving material.
There is a possibility that the stirring / mixing means may be locked.
Therefore, it is necessary to provide a relief valve upstream of the throttle to protect the hydraulic circuit. However, there is a case where the processing unit is stopped and the excavating means is driven, and in this case, since the state becomes substantially the same as the state where the stirring / mixing means is locked, the pressure on the priority flow path side increases. The relief valve will open. When this happens,
The discharge flow rate from the hydraulic pump will be reduced, and the operation of the excavating means and the like cannot be performed smoothly. Therefore,
In order to prevent this, a configuration in which a vent flow path is connected to a relief valve provided on the downstream side of the throttle and the other end of the vent flow path is connected to a hydraulic oil tank via an on-off valve can be adopted. Therefore, when the agitation hydraulic motor is operated, the on-off valve is closed so that the relief valve is not operable, and when the agitation hydraulic motor is stopped, the relief valve is opened to substantially set the pressure of the relief valve to the tank pressure. It is preferable that the on-off valve be configured to open and close in conjunction with a direction switching valve for controlling the operation of the stirring hydraulic motor.

[0018]

Embodiments of the present invention will be described below with reference to the drawings. Here, the excavation mechanism provided in the soil improvement machine of the present invention has the same configuration as the excavation mechanism in the hydraulic excavator. Therefore, the basic configuration of the soil improvement machine is a conventionally known hydraulic excavator. The soil improvement mechanism is mounted without impairing the function as a hydraulic excavator and without making any special modifications to the configuration as a hydraulic shovel.

FIGS. 1 to 3 show the overall construction of the soil improvement machine of the present invention. As is apparent from these drawings, a work vehicle is constituted by the lower traveling body 1 and the upper revolving superstructure 2, and a front work mechanism 3 as an excavation mechanism is provided on the upper revolving superstructure 2 in this work vehicle. Further, a processing unit 4 is provided on the lower traveling unit 1 side, and the upper revolving unit 2 is provided.
On the side, soil improvement material supply means 5 is installed. Further, an operator's cab 6 and a machine room 7 are installed in the upper revolving superstructure 2, and the machine room 7 accommodates equipment for driving the machine such as an engine and a hydraulic pump. After boarding, the entire machine is operated.
The upper revolving unit 2 can be turned with respect to the lower traveling unit 1 by a turning device 8.

The lower traveling body 1 has crawler-type traveling bodies 10 provided on the left and right sides. The both traveling bodies 10 include sprockets 12 and idlers 13 provided at both ends of a track frame 11, and these sprockets 12 and idlers 13 The sprocket 12 is driven by a hydraulic motor. The left and right track frames 11 are connected by a center frame 15, and the turning device 8 is attached to the center frame 15. Here, the center frame 15 is connected to the turning device 8.
The track frame 11 is connected to both ends of the horizontal portion where the horizontal frame is installed, so that a wide space is secured below the center frame 15.

The front working mechanism 3 constitutes excavating means, and is connected to a boom 16 provided on the frame 2a of the upper swing body 2 so as to be capable of raising and lowering, and to the tip of the boom 16 so as to be rotatable vertically. Arm 17 and this arm 1
The boom 16, the arm 17, and the bucket 18 are driven by hydraulic cylinders 16a, 17a, and 18a, respectively, to perform operations such as excavation of earth and sand.

The processing unit 4 has the configuration shown in FIGS. The processing unit 4 is shown in FIGS.
As can be seen from FIG. 1, it is composed of a sediment charging section 20, a continuous processing tank 21, and a discharging means 22. Continuous treatment tank 2
As shown in FIG. 6, reference numeral 1 denotes a shallow container whose length in the length direction is longer than that in the width direction, and the upper surface and the rear end are open. A screw conveyor 23 as stirring / mixing means for stirring / mixing while being transferred from the front side to the rear side in the continuous processing tank 21.
Are provided in parallel. As described above, since the continuous processing tank 21 is installed on the lower traveling body 1, its longitudinal dimension is limited, and in order to efficiently stir and mix in the restricted transfer path. These screw conveyors 23 are intermittently arranged on the outer peripheral surface of the rotating shaft 23a at a predetermined angle with respect to the axis thereof.
b. Each of the four screw conveyors 23 has a length substantially corresponding to the entire length of the continuous processing tank 21, and the blades 23b, 23b of the adjacent screw conveyors 23, 23 are inclined in opposite directions. As shown in FIG. 7, the blade 23b extends to a position close to the rotation shaft 23a of the screw conveyor 23 adjacent thereto.

Both ends of each screw conveyor 23 are bearings 2
The ends of the rotating shafts 23a are extended into the housing of the driving unit 25 provided at the front end of the continuous processing tank 21, as shown in FIG. I have. A transmission gear 26 is connected to the tip of each rotating shaft 23a, and the transmission gears 26, 26 at adjacent positions are arranged.
Are engaged with each other, so that when one rotation shaft is rotated, the other three rotation shafts are also driven to rotate.
However, adjacent rotating shafts 23a, 23a rotate in opposite directions. A pulley 27 is mounted on one rotating shaft, that is, a rotating shaft indicated by reference numeral 23a 'in FIG.
A hydraulic motor 28 for stirring is provided in the housing of the hydraulic motor 28. The output shaft of the hydraulic motor 28 for stirring has a pulley 2
A transmission member 30 such as a chain or a belt is provided between these pulleys 27 and 29 by winding. As a result, the entire inside of the continuous processing tank 21 having a predetermined width and length can be stirred by the single stirring hydraulic motor 28.

The charging section 20 is attached so as to be joined to the upper part of the front end of the continuous processing tank 21. The input section 20 is an input port 20a having an open upper end,
The entrance 20a is provided with a cage 31 to prevent a lump of rock, concrete or the like, metal or the like from entering. In addition, the inlet 20a is inclined obliquely downward toward the front, so that the lump or the like remaining on the pen 31 is likely to fall along this inclination. 9 is provided inside the charging section 20.
As shown in (1), forcible feeding means 32 for forcibly feeding earth and sand is provided. The forcible feeding means 32 has a large number of scraping claws 32b attached to a rotary shaft 32a. When the rotary shaft 32a is driven to rotate by a hydraulic motor, the earth and sand introduced into the input port 20a is forcibly removed from the continuous processing tank 21. It is to be sent to.
Therefore, even if the soil to be treated contains water and is in the form of clay, it can be taken in smoothly without causing a bridging phenomenon at the portion of the inlet 20a.

Further, the discharge means 22 is connected to the rear end of the continuous processing tank 21. The discharging means 22 includes a frame-shaped connecting portion 33 fitted into the continuous processing tank 21 and a connecting portion 3.
3 and a main body 34 connected to the main body 3. Main unit 34
Has a discharge passage 35 composed of front and rear wall surfaces and a bottom wall, and the discharge passage 35 is provided with a discharge conveyor 36 as forcible discharge means. As shown in FIG. 10, the discharge conveyor 36 has pulleys 38a and 38b attached to rotating shafts 37a and 37b provided at both ends of the discharge passage 35, and a discharge plate 39 is provided between the pulleys 38a and 38b. A large number of belts 40 projecting at pitch intervals are wound and provided. Therefore, the rotating shaft 37a or 37b
When the rotary shaft is driven by the hydraulic motor 41, the belt 40 is fed and passes from the continuous processing tank 21 through the connecting portion 33 of the discharging means 22 to the main body 3.
The improved soil sent into the discharge passage 35 from the communicating portion 42 formed on the wall surface of the fourth wall 4 is forcibly discharged from the discharge port 35a by the discharge plate 39. Here, the discharge passage 35 is formed in a direction orthogonal to the traveling direction of the work vehicle, and the discharge port 35a side is inclined in a rising direction, and the discharge port 35a is located at a position higher than the position of the continuous processing tank 21. ,
Moreover, it is located outside the ground contact surface of the crawler belt 14 in the lower traveling body 10. A guide member 43 is provided on the wall surface of the main body 34 to guide the belt 40 along the discharge passage 35.

FIGS. 11 and 12 show a structure for attaching the processing unit 4 to the lower traveling body 1. FIG. The charging section 20 is fixedly connected to the continuous processing tank 21, and the continuous processing tank 21 is connected to the discharging means 2.
2 so as to be slidable with respect to 2. And, the continuous processing tank 21 is provided with the center frame 1 of the undercarriage 1.
5, the continuous processing tank 21 is supported at a predetermined angle with respect to the center frame 15. Further, the frame-shaped connecting portion 33 in the discharging means 22
Are also fixed to the center frame 15 so as to be inclined at the same angle as the continuous processing tank 21. The inclination direction of the continuous processing tank 21 and the connecting portion 33 is the same as the charging portion 20.
Side faces downward, and the discharge means 22 side faces obliquely upward.

A mounting member 44 having an inclined surface is fixed to the lower surface of the center frame 15 by means of welding or the like. The connecting part 33 constituting the discharging means 22 is connected to the mounting member 44 by means of welding or the like. It is fixed by means. On the other hand, as shown in FIG. 11, the continuous processing tank 21 is mounted on the center frame 15 so as to be able to move back and forth, and for this purpose, brackets 45 are provided on the left and right side walls of the continuous processing tank 21. As shown in FIG. 12, the bracket 45 is provided with a plurality of rollers 46 at predetermined intervals. A pair of left and right guide rails 47 are fixedly provided on the lower surface of the center frame 15, and the rollers 46 roll on the guide rails 47. Here, the guide surface 47 a of the guide rail 47 on which the roller 46 rolls gives the continuous processing tank 21 an inclination.
It is inclined to fall forward. further,
Main body 34 having discharge passage 35 in discharge means 22
Is in a horizontal state.

The charging section 2 fixedly provided in the continuous processing tank 21
A hydraulic cylinder 48 for moving the continuous processing tank 21 is provided between the casing 0 and the center frame 15. When the hydraulic cylinder 48 is held in a contracted state, the continuous processing tank 21 is held in a state of being drawn toward the discharge means 22 side. As a result, during normal earth and sand excavation by the bucket 18, the charging unit 20 is moved rearward, so that the operation of the bucket 18 is not obstructed. Can be made wider. On the other hand, when the hydraulic cylinder 48 is extended, the continuous processing tank 21 projects obliquely downward, and the input section 20 is pushed forward. As a result, the earth and sand excavated by the bucket 18 can be smoothly injected into the input section 20.

When earth and sand are injected from the charging section 20 into the continuous processing tank 21, the earth and sand are conveyed rearward while being stirred by the operation of the screw conveyor 23, during which the state of lumps is loosened and the state of sand particles is released. become. Then, a soil improvement material such as cement is supplied at a position in the middle of transportation, and the soil improvement material is uniformly mixed with the earth and sand. For this purpose, a soil improving material supply means 5 is provided on the upper revolving superstructure 2 side. This soil improvement material supply means 5 is shown in FIG.
As shown in FIG. 3, a tank 50 for supplying soil improvement material is provided.
Is fixed to the frame 2a. The tank 50 has a cylindrical shape, and its lower end has a conical shape. The feeder 51 is connected to the lower end of the tank 50.

The feeder 51 is, as shown in FIG.
It is a cylindrical member, and is bent horizontally from the lower end of the tank 50. A screw 52 is provided in the horizontally extending portion, and the screw 52 is driven to rotate by a hydraulic motor 53. As a result, a constant amount of the soil improving material in the tank 50 can be continuously supplied. The feeder 51 is bent again and directed downward. The feeder 51 is located at a position higher than the upper surface of the center frame 15 of the lower traveling body 1, and a flexible cylinder 54 is connected to a lower end of the feeder 51 as a supply part of a soil improving material. This flexible cylinder 54 is formed of a rubber cylinder having a waist, and a plurality of cuts are formed in the axial direction to the lower end except for a part of the upper end thereof,
It has the shape of a streamer. When the upper revolving unit 2 is directed forward in the traveling direction of the vehicle, the flexible tubular body 54 is connected to the two central screw conveyors 2 in the continuous processing tank 21.
An opening is provided at an intermediate position between 3, 23. Also, when the upper swing body 2 is largely swung, the flexible tubular body 54 comes into contact with the center frame 15, but since the flexible tubular body 54 is formed of a blow-down rubber cylinder, it is easily deformed. As a result, the vehicle smoothly rides on the center frame 15 so that a bend or the like does not occur.

When performing soil improvement on a predetermined ground using the soil improvement machine configured as described above,
First, when the surface portion of the ground is high-quality soil, the soil in the surface portion is excavated. The surface soil is carried out of the site by a dump truck or the like and is deposited at a predetermined position.
Is provided and the crawler belt 14 having a large ground contact area is provided as a traveling means, so that the excavation of the surface soil can be performed by the soil improvement machine itself. In soft lands such as wetlands, the soil must be improved, including the surface layer. Here, the ground after excavation of the surface soil is uneven, and the running conditions are poor, and the running conditions are also poor on soft ground. However, the soil improvement machine according to the present invention is a running body 10 using the crawler belt 14. Therefore, the work vehicle can smoothly travel even in a place where the traveling conditions are poor.

Therefore, in order to perform ground improvement work using this soil improvement machine, for example, as shown in FIG. 15, earth and sand in a linear excavation area having a predetermined width B is excavated. Further, the excavated soil is uniformly mixed with the soil improvement material using the processing unit 4 so that the improved soil is parallel to the excavation area, and on the opposite side of the running area of the soil improvement machine. The improved soil is deposited on C. Then, after the improved soil is deposited in the area C, the improved soil is backfilled at the excavation site, and then the ground is leveled and compacted.

First, when excavating the surface soil, the continuous processing tank 21 is retracted by reducing the hydraulic cylinder 48, and the charging section 20 is retracted toward the work vehicle. By operating the front working mechanism 3 in this state, excavation of the surface soil can be performed. The excavated surface soil is carried out by a dump truck or the like. After all surface soil at the work site has been removed, the ground itself is soft and uneven.

The left and right traveling bodies 10 of the lower traveling body 1
10 to drive the entire work vehicle at a predetermined work position. Therefore, the charging section 20 is made to project forward by extending the hydraulic cylinder 48 and making the continuous processing tank 21 project. In this state, the front working mechanism 3 is operated to excavate earth and sand, and the excavated earth and sand is injected into the input section 20. Since the feeding section 20 is provided with the forced feeding means 32, the earth and sand fed into the feeding section 20 is smoothly fed into the continuous processing tank 21. Further, since the pond 31 is attached to the input port 20a, rocks, metals, and the like are separated, and only earth and sand are taken in. Since the four screw conveyors 23 are provided in the continuous processing tank 21, the earth and sand introduced by the rotation of the screw conveyor 23 is finely crushed and stirred, and becomes a state of sand grains toward the rear side. Transported. The earth and sand are sequentially charged into the charging section 20 by the operation of the bucket 18 of the front working mechanism 3 and supplied into the continuous processing tank 21.

The earth and sand supplied into the continuous treatment tank 21 is transported to the tank 5 constituting the soil improving material supply means 5 during the transportation.
From 0 through the feeder 51, the soil improvement material is
The water is continuously supplied by a constant amount into the inside, and is added to the earth and sand at a position on the way of being conveyed while stirring. Accordingly, the earth and sand and the soil improvement material are stirred by the rotation of the screw conveyor 23, and are uniformly mixed. Then, the soil improvement material is supplied from the tank 50 to the feeder 51 and the flexible cylinder 54.
Can be directly supplied to the continuous treatment tank 21 via the slag, and there is no possibility that the soil improvement material will be scattered around. Improved soil is generated by uniformly mixing the soil and soil improvement material,
This improved soil is discharged from the rear end of the continuous
You will be pushed out towards.

The continuous processing tank 21 is provided with four screw conveyors 23, and the adjacent screw conveyors are configured to rotate in opposite directions. By rotating as shown in FIG. 7, the lump of earth and sand can be completely broken, and it can be uniformly mixed with the soil improvement material. That is, between the two screw conveyors at the center, the earth and sand and the soil improvement material form a flow directed downward from above, and the flow between the screw conveyors at both ends thereof flows downward from above and reverse. Is formed, the agitation and mixing are performed very smoothly throughout the continuous processing tank 21. Here, supply of soil improvement material is
The position between the two central screw conveyors is convenient for uniformly stirring and mixing the whole. However, since the entire inside of the continuous processing tank 21 is uniformly stirred by the four screw conveyors 23, the upper revolving superstructure 2 is rotated during excavation, and the feed position of the soil improvement material by the feeder 51 is slightly different. Even if it is shifted to the left or right, there is no particular mixing unevenness.

Furthermore, the connecting portion 33 of the continuous processing tank 21 and the discharging means 22 connected thereto is inclined, and the conveying direction of the soil and soil improving material by the screw conveyor 23 of the continuous processing tank 21 is obliquely upward. ing. Therefore,
The earth and sand and the soil improvement material added thereto are transported in a direction against gravity. As a result, due to the resistance due to the inclination of the feed by the screw conveyor 23, the residence time of the earth and sand and the soil improvement material becomes substantially longer than when the continuous treatment tank 21 is arranged in the horizontal direction,
The efficiency of stirring the soil and soil improvement material per unit length is improved. In addition, the earth and sand which are not crushed by the screw conveyor 23 and are clumped will be exposed on the surface during the stirring, and such clumps will be returned by their own weight in the direction toward the base end in the transport direction. . And it is sent in the conveyance direction again by rotation of the screw conveyor 23, during which the lump is crushed smoothly and reliably, and is uniformly mixed with the soil improvement material.

Therefore, due to the mounting on the lower traveling body 1, the soil and the soil improving material can be uniformly and efficiently mixed in the continuous processing tank 21 which is small and has a short conveying path. This stirring / mixing is also carried out even after moving into the connecting portion 33 of the discharging means 22, during which the earth and sand and the soil improvement material are uniformly mixed to form an improved soil, and the improved soil is It is fed into the discharge passage 35 from the communication part 42 formed on the wall surface of the part 34.

In the discharging means 22 to which the improved soil generated as described above is sent out, a belt 40 provided with a discharging plate 39 is mounted. Is transported in a direction orthogonal to the traveling of the work vehicle, discharged from the discharge opening 43 and deposited. Here, the opening 43 is located outside the crawler belt 10 and the continuous processing tank 21.
Is located at the uppermost portion inclined obliquely upward, and is open at a higher place than the continuous processing tank 21, so that the crawler belt 10 does not step on the improved soil on which the crawler belt 10 has been deposited, and has a predetermined height. Improved soil can be deposited up to. Moreover,
Since the processing unit 4 is provided on the lower traveling body 1 side, even if the upper rotating body 2 is turned, the discharge position of the improved soil does not change. Further, the inclined portion from the continuous processing tank 21 to the connecting portion 33 of the discharging means 22 is inclined, but the main body portion 34 is in a horizontal state, so that the improved soil to be discharged is uniformly discharged from the entire opening 43. .

While the work vehicle is running, the work is excavated to a predetermined depth by the front work mechanism 3, and the soil can be continuously improved to deposit the improved soil in parallel with the excavation area. When the work consisting of one line-shaped excavation and accumulation of the improved soil is completed, returning the work vehicle,
Backfill the improved soil at the excavation site. When the ground improvement by excavation and backfilling of one linear excavation area having a predetermined width is completed, the excavation area adjacent to this excavation area is similarly excavated to a line and backfilling of the improved soil is performed. . Thus, the excavation is continuously excavated by the bucket 18 while the work vehicle is self-propelled, and the agitation of the soil and the mixing of the soil improvement material by the continuous treatment tank 21 can be continuously performed. Since the reclaimed soil that can be generated and backfilled is located on the side of the work vehicle, the backfill work can be performed smoothly and quickly.

As described above, the soil improvement work on the ground is performed using the soil improvement machine. The work involved in this work includes excavation work alone and excavation of soil and the continuous treatment tank 21. There is a combined excavation and treatment operation in which the earth and sand and the soil improvement material are agitated and mixed. Here, at the time of the excavation alone operation, the processing unit 4 is held in a stopped state, and the operation is performed by traveling by the lower traveling body 1, turning the upper revolving body 2, and operating the front operation mechanism 3. On the other hand, at the time of the excavation-processing combined work, at least the front working mechanism 3 is operated, and the traveling by the lower traveling body 1 and the turning of the upper revolving body 2 are performed as necessary.
Further, the processing unit 4 operates. Therefore,
In order to smoothly and efficiently perform the excavation alone operation and the excavation-processing combined operation, the hydraulic drive device is configured as shown in FIGS. 16 to 18.

First, FIG. 16 shows a schematic configuration of the entire hydraulic drive circuit. In the figure, 60a and 60b are main pumps, 61 is a direction switching valve unit, and 62 is a hydraulic oil tank. Main pump 60a, 60b
Is driven by an engine (not shown) to pressurize and discharge the hydraulic oil sucked from the hydraulic oil tank 62, and the pressure oils from both the main pumps 60a and 60b merge on the way. In addition, both main pumps 60
The pumps a and 60b are constituted by variable displacement pumps, and the discharge flow rates thereof are controlled by operating the regulators 63a and 63b of the main pumps 60a and 60b in accordance with the discharge pressure. Further, 64 is a pilot pump, and 65 is a fixed displacement pump for operating, for example, the hydraulic motor 41 for driving the discharging means.

The directional control valve unit 61 comprises a plurality of directional control valves, each of which is connected to a hydraulic actuator. Accordingly, the hydraulic oil supplied from the main pumps 60a and 60b can drive the hydraulic actuators provided in the respective working units constituting the work vehicle by performing the switching operation of these directional switching valves. . And
In order to perform a switching operation of each directional switching valve constituting the directional switching valve unit 61, operating means such as an operating lever is provided in the cab 6, and an operator controls the supply of pressure oil to each hydraulic actuator. I can do it.
Here, as hydraulic actuators controlled by the direction switching valve unit 61, left and right traveling hydraulic motors constituting the lower traveling body 1 and a turning hydraulic motor for rotating the upper rotating body 2, and excavation of earth and sand, etc. , A hydraulic cylinder 16 a for driving the boom 16, the arm 17 and the bucket 18 constituting the front working mechanism 3,
17a and 18a.

In addition to the above hydraulic actuator, a hydraulic motor 28 for stirring is provided for rotationally driving a screw conveyor 23 for stirring the inside of the continuous processing tank 21 in the processing unit 4. The agitation hydraulic motor 28 drives the four screw conveyors 23 to agitate the earth and sand and the soil improvement material, so that a large load is applied. It is configured to be driven by the pumps 60a and 60b. Thus, the stirring hydraulic motor 2
8 can be driven smoothly, and the entire hydraulic circuit configuration can be simplified.

The stirring hydraulic motor 28 is
0a and 60b are connected to each other through a flow rate priority means 70 and a control valve 71, whereby the flow rate is preferentially assigned to other hydraulic actuators. Thus, the flow priority means 70 has the diversion control valves 72a, 72b, and these two diversion control valves 72a, 72b.
The discharge ports of the main pumps 60a and 60b are connected to the input ports P ₁ and P ₂ of 2b, respectively. Flow control valve 72
a and 72b have first output ports A ₁ and A ₂ and second output ports B ₁ and B ₂ . First output port A
₁ and A ₂ are respectively connected to the directional control valve unit 61, and the second output ports B ₁ and B ₂ are merged on the way,
It is connected to the control valve 71. The variable apertures 73a and 73b are connected to the second output ports B ₁ and B _2.
The variable throttles 73a and 73b make the flow rate of the pressure oil supplied to the stirring hydraulic motor 28 constant. Therefore, the first output port A ₁ ,
A ₂ The remaining pressure oil is adapted to be supplied with supply pressure oil of a predetermined amount of agitation hydraulic motor 28.

Here, as a specific configuration of the flow control valves 72a and 72b, a spool 75 is slidably mounted in a valve casing 74, as is apparent from FIGS. Spool 75 in valve casing 74
By moving the input ports P ₁ and P ₂
The second output ports B ₁ and B ₂ are connected to each other, the first output ports A ₁ and A ₂ are cut off, and the second output ports B ₁ and B ₂ and the first output port A ₁ , A _2, and the opening ratio of both ports is changed according to the position of the spool 75. Here, the spool 75 is provided with the variable throttles 73a and 73b.
The spool 75 is moved based on the differential pressure between before and after the pressure action chambers 76 and 77. The upstream and downstream pressures of the variable throttles 73a and 73b are led to the pressure action chambers 76 and 77, respectively. Further, a spring 78 is provided on the pressure application chamber 77 side where the pressure on the upstream side of the variable throttles 73a and 73b acts, and this spring 78 moves the spool 75 leftward in the drawing, that is, the input ports P ₁ and P _2.
Are connected to the second output ports B ₁ and B ₂ , and are turned off so as to be cut off from the _first output ports A ₁ and A ₂ .

Further, a relief valve 80 is connected to the flow path 79 to the pressure action chamber 77 side, and the second output port B
When _1, B ₂ of the output pressure exceeds the set value, the relief valve 8
0 is opened and the hydraulic oil tank 62 is relieved. Thus, even if the screw conveyor 23 connected to the agitating hydraulic motor 28 is locked due to, for example, biting in rocks, the relief valve 8
When the pressure rises above the set pressure of 0, the relief valve 8
Since 0 is opened, there is no inconvenience that each part of the hydraulic circuit is damaged due to abnormally high pressure.

For example, when the control valve 71 is switched to operate the agitation hydraulic motor 28 while the excavation alone operation is being performed, a predetermined amount of pressure oil is supplied through the diversion control valves 72a and 72b. In order to be able to supply to the hydraulic motor 28 for stirring,
A state in which a small amount of pressure oil flows through 3a and 73b is maintained. Then, when the control valve 71 is held at the neutral position in a state where the operation of the stirring hydraulic motor 28 is stopped, for example, when the front working mechanism 4 is driven to excavate earth and sand, the stirring hydraulic motor 2 is stopped.
8 is locked, and the second output ports B ₁ and B ₂ are close to the pump pressure. As a result,
The relief valve 80 operates, and the pressure on the pump side rises at least to the set pressure of the relief valve 80 even though the second output ports B ₁ and B ₂ are not working. . As a result, the regulators 63a, 6
3b operates to reduce the discharge flow rate of the main pumps 60a and 60b, and there is a possibility that the work efficiency at the time of excavating earth and sand by the front work mechanism 4 may decrease.

In order to prevent the above inconvenience, a vent flow path 81 is connected upstream of the relief valve 80, and this vent flow path 81 is connected to the hydraulic oil tank 62 via an on-off valve 82. It is configured as follows. The on-off valve 82 opens and closes in conjunction with the control valve 71. When the control valve 71 is in the neutral position,
That is, when the operation of the stirring hydraulic motor 28 is stopped, the on-off valve 82 is opened, and when the control valve 71 is switched to the left or right switching position, the on-off valve 82 is closed. As a result, when the stirring hydraulic motor 28 is operating, a predetermined set pressure is given to the relief valve 80. When the operation of the stirring hydraulic motor 28 is stopped, the relief pressure of the relief valve 80 is substantially reduced to the tank pressure. Pressure.
When the pressure of the relief valve 80 is substantially equal to the tank pressure, the pressure of the pressure action chamber 77 is also equal to the tank pressure, so that the spool 75 of the flow dividing control valves 72a and 72b is displaced to the rightmost position. And the second output port B
_1, B ₂ and the first output port A _1, of the opening ratio of A _2, the first output port A _1, A ₂ is held in a state of opening to the maximum, the supply main pump 60a, from 60b The pressure oil to be supplied is substantially all of the directional valve unit 61.
To the side. As a result, when the switching operation of each direction switching valve constituting the direction switching valve unit 61 is performed,
A required amount of pressure oil is supplied to each hydraulic actuator. Therefore, for example, the boom 16, the arm 17, and the bucket 18 constituting the front working mechanism 4 are driven to perform the excavation alone work without performing the soil improvement. In addition, during the excavation alone operation, of course, a combined operation such as the turning of the upper revolving unit 2 and the traveling of the lower traveling unit 1 can be performed.

On the other hand, when performing a combined excavation-processing operation in which excavation of earth and sand and soil improvement processing are performed in parallel, the above-described front working mechanism 4 and the like are operated and the processing unit 4 is operated.
The screw conveyor 23 constituting the stirring / mixing means in the continuous processing tank 21 constituting the above is operated. For this,
At least a boom 16, which constitutes the front working mechanism 4,
The hydraulic cylinders 16a, 17a, 18a, which are hydraulic actuators for the arm 17 and the bucket 18, and the agitation hydraulic motor 28 for operating the screw conveyor 23 operate simultaneously in parallel.

To start the combined excavation and processing work, the control valve 71 is switched from the neutral position to one of the left and right switching positions. Since the on-off valve 82 is closed in conjunction with the switching of the control valve 71, communication of the vent flow path 81 with the hydraulic oil tank 62 is cut off.
The relief valve 80 comes to a state having a predetermined set pressure which is an original characteristic thereof. Here, even during the above-described excavation alone operation, although the flow rate is only a very small amount, a flow path is formed through the second output ports B ₁ and B ₂ . The pressurized oil is returned to the hydraulic oil tank 62, but when the on-off valve 82 is closed and the vent flow path 81 is closed, pressure rises upstream of the relief valve 80, and this pressure acts as a pressure action. As a result of being guided to the chamber 77, the pressure in the pressure action chamber 77 increases, and the spool 75 is pushed toward the pressure action chamber 76.

Here, the spool 7 is located on the pressure action chamber 77 side.
5, the second output ports B ₁ , B are provided as long as the main pumps 60a, 60b supply hydraulic oil at a flow rate equal to or greater than the flow rate set by the variable throttles 73a, 73b. ₂ to the stirring hydraulic motor 28,
Pressurized oil at a flow rate necessary for rotating the screw conveyor 23 in the rated state is preferentially supplied. When the pressure oil at or above this flow rate is supplied, the spool 75
The amount of movement of the pressure oil becomes large, and the excess pressure oil is supplied to the first output ports A ₁ and A ₂ . As a result, the operation of the front working mechanism 4 and the like becomes possible. Therefore, the screw conveyor 23 provided in the continuous treatment tank 21 is driven by the stirring hydraulic motor 28 in parallel with the excavation of the earth and sand, and the earth and soil introduced by the excavation are stirred and soil-improved.
A combined excavation-processing operation of mixing can be performed.

When excavating earth and sand by operating the front working mechanism 4, large excavation resistance may be generated depending on the excavation location and the like. When the excavation resistance is large, the pressure of the pressurized oil supplied from the main pumps 60a and 60b increases, so that the discharge flow rate decreases. Even if the flow rate is reduced in this manner, the operation of the screw conveyor 23 is performed because the required amount of pressure oil is always supplied to the stirring hydraulic motor 28 by the action of the flow rate priority means 70. The earth and sand and the soil improvement material are uniformly stirred and mixed at a predetermined efficiency without any influence. Therefore, it is possible to always produce improved soil with a constant quality. In addition, the excavated soil and the soil improvement material can be uniformly stirred and mixed with a predetermined efficiency in the continuous processing tank 21 regardless of the fluctuation of the work load by the front working mechanism 4 or the like, so that the excavated soil and the soil There is no need for the improvement material to stay in the continuous treatment tank 21 for a required time or more, and a high-quality improved soil can be generated in a minimum time using the small and compact continuous treatment tank 21.

In addition, since the flow rate of the pressure oil supplied to the stirring hydraulic motor 28 can be adjusted by the flow rate priority means 70, the flow rate of the pressure oil can be adjusted according to the type and properties of the soil to be treated.
By appropriately adjusting the throttle amounts of the variable throttles 73a and 73b, it is possible to secure the flow rate required for the uniform and efficient stirring and mixing of the stirring hydraulic motor 28 in the continuous processing tank 21.

FIGS. 19 and 20 show relief valves which are attached to the respective valve casings 74 constituting the flow dividing control valves 72a and 72b and which exert a relief function only when the stirring hydraulic motor 28 is operated. It can also be configured as follows. As is clear from these figures, the relief valve 90 has a poppet 94 which comes into contact with and separates from a valve seat 93 formed in a relief flow passage 92 formed in a casing 91, and the poppet 94 is seated on the valve seat 93. The spring 95 acts in the direction. The other side of the spring 95 is in contact with the balance piston 96. The balance piston 96 can move in the direction approaching or separating from the poppet 94 along the casing 91 by the pressure acting on the back pressure chamber 97. A vent passage 9 is provided in the back pressure chamber 97.
8 is connected, and this vent passage 98 is connected to a switching valve 99.
Through the hydraulic oil tank 62 or the pilot pump 1
00 is selectively connected.

The switching valve 99 is opened and closed in conjunction with the control valve 71 (see FIG. 16). When the control valve 71 is in the neutral position, that is, when the operation of the stirring hydraulic motor 28 is stopped. The switching valve 99 connects the back pressure chamber 97 to the hydraulic oil tank 62, and when the control valve 71 is switched to one of the left and right switching positions, the switching valve 99 receives the back pressure from the pilot pressure from the pilot pump 100. It is led to the room 97.

Therefore, when the agitation hydraulic motor 28 is operated, the discharge pressure from the pilot pump 100 acts on the back pressure chamber 97, and this pressure is applied to the balance piston 9.
6, the balance piston 96 is displaced in a direction against the spring 95, so that the spring 95 is bent by a predetermined amount. As a result, the spring 95 acts on the poppet 94 in the direction of pressing against the valve seat 93, so that a predetermined relief pressure is applied to the relief valve 90 by bending of the spring 95. Here, since the pilot pump 100 is constituted by a fixed displacement pump, the pressure acting on the back pressure chamber 97 via the vent passage 98 is constant, so that the relief pressure is always kept constant.

On the other hand, during the excavation alone operation, the switching valve 99 is switched to a state in which the vent flow path 98 is connected to the hydraulic oil tank 62, and the back pressure chamber 97 is substantially at the tank pressure. As a result, the spring 95 expands and displaces the balance piston 96 in a direction away from the poppet 94, so that the balance piston 96 comes into contact with the wall surface of the back pressure chamber 97 as shown in FIG. Since the distance between the balance piston 94 and the balance piston 96 increases, the spring 95
Becomes substantially natural. As a result, the function as the relief valve is lost, and there is no possibility that the amount of oil supplied to each hydraulic actuator constituting the front working mechanism 4 and the like is reduced.

[0059]

As described above, according to the present invention, the improved soil is continuously produced by charging the earth and sand excavated by the excavating means and mixing and stirring with the soil improving material. In this continuous treatment tank, the agitation / mixing means for agitating / mixing the soil and soil improvement material is driven by a hydraulic motor for agitation. By using the same hydraulic motor as the hydraulic power source for the excavating means as the hydraulic power source for the agitation hydraulic motor, the configuration of the drive mechanism is simplified, and the agitation hydraulic motor is provided via the flow rate priority means. Because it is connected to a hydraulic pump, a constant flow of hydraulic oil is always supplied to the agitation hydraulic motor even if the work load caused by the excavation means fluctuates. Using a continuous processing tank In addition, it is possible to efficiently mix and mix the earth and sand with the soil improvement material, and to produce a uniform and high quality improved soil in which the soil and the soil improvement material are mixed extremely uniformly. Play.

[Brief description of the drawings]

FIG. 1 is a side view of a soil improvement machine with excavation means showing one embodiment of the present invention.

FIG. 2 is a front view of FIG. 1 omitting a front working mechanism.

FIG. 3 is a plan view of FIG. 1 omitting a front working mechanism.

FIG. 4 is a plan view of a processing unit.

FIG. 5 is a side view of FIG. 4;

FIG. 6 is an exploded perspective view of the processing unit.

FIG. 7 is a cross-sectional view of a continuous processing tank.

FIG. 8 is an explanatory diagram of a configuration of a driving mechanism of a screw conveyor.

FIG. 9 is a sectional view of a charging section.

FIG. 10 is a cross-sectional view of the discharging means.

FIG. 11 is a structural explanatory view showing a forward and backward movement drive mechanism of the continuous processing tank.

FIG. 12 is a sectional view taken along line XX of FIG. 11;

FIG. 13 is an external view showing a configuration of a soil improving material supply unit.

FIG. 14 is a sectional view of a feeder.

FIG. 15 is an explanatory diagram showing a procedure of soil improvement by a soil improvement machine.

FIG. 16 is a hydraulic circuit diagram showing a hydraulic drive mechanism of the soil improvement machine.

FIG. 17 is a circuit configuration diagram of a flow rate priority unit.

FIG. 18 is a cross-sectional view showing a configuration of a flow dividing control valve constituting a flow rate prioritizing means.

FIG. 19 is a circuit configuration diagram showing another configuration example of the flow rate prioritizing means.

20 is a cross-sectional view showing the configuration of a flow dividing control valve constituting a flow priority means in FIG. 19 and a relief valve attached thereto.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 Lower traveling body 2 Upper revolving superstructure 3 Front working mechanism 4 Processing unit 5 Soil improving material supply means 10 Traveling body 16 Boom 17 Arm 18 Bucket 20 Input section 21 Continuous processing tank 22 Discharge means 23 Screw conveyor 25 Drive section 28 Stirring hydraulic pressure Motor 60a, 60
b Main pump 61 Direction switching valve unit 62 Hydraulic oil tank 70 Flow rate priority means 71 Control valve 72a, 72b Dividing control valve 73a, 73
b Variable throttle 74 Valve casing 75 Spool 76, 77 Pressure action chamber 80, 90
Relief valve 81,98 Vent flow path 82 On-off valve 99 Switching valve 100 Pilot pump

 ──────────────────────────────────────────────────続 き Continued on the front page (72) Inventor Satoshi Sekino 650, Kandamachi, Tsuchiura-shi, Ibaraki Pref.

Claims (7)

[Claims] 1. An upper revolving structure is installed on a lower traveling structure having a pair of left and right crawler tracks so as to be revolvable, and excavating means is mounted on the upper revolving structure, and at least the excavating means is operated by pressure oil from a hydraulic pump. The work vehicle has a hydraulically driven work vehicle, and the work vehicle is equipped with a processing unit that generates improved soil by receiving the earth and sand excavated by the excavation means and mixing with the soil improvement material. Is composed of a continuous treatment tank and stirring / mixing means driven by a stirring hydraulic motor for stirring / mixing with the soil improvement material while moving the excavated soil in the continuous treatment tank. By connecting a hydraulic motor to the hydraulic pump through a flow priority means, a constant flow rate is supplied to the stirring hydraulic motor regardless of fluctuations in the load acting on the excavating means. Soil improvement machine with excavation means. 2. The flow rate prioritizing means includes a flow dividing control valve connected to a discharge side of the hydraulic pump, for diverting pressure oil from the hydraulic pump, and a control valve on a priority flow path side of the flow dividing control valve. The agitation hydraulic motor is connected via the control valve, and a throttle is provided between the diversion control valve and the control valve for flowing a predetermined amount of pressure oil to the agitation hydraulic motor. A soil improvement machine provided with the excavating means according to claim 1. 3. The soil improvement machine with excavating means according to claim 2, wherein said throttle is a variable throttle. 4. A relief valve is provided downstream of the throttle and connected to the vent valve, and the other end of the vent channel is connected to a hydraulic oil tank via an on-off valve. The opening / closing valve is configured to be in a closed state when the agitation hydraulic motor is operating, and to connect the vent flow path to the hydraulic oil tank when the agitation hydraulic motor is stopped. A soil improvement machine comprising the excavation means according to 3. 5. The soil improvement machine with excavation means according to claim 4, wherein said on-off valve is configured to open and close in conjunction with a direction switching valve for controlling operation of said agitation hydraulic motor. 6. A relief valve is connected to a downstream side of the throttle, and a relief valve is connected to a vent passage. The other end of the vent passage is connected to a hydraulic oil tank and a pilot pump via a switching valve. The switching valve is connected to the pilot pump when the agitation hydraulic motor is operating, and the vent passage is connected to the hydraulic oil tank when the pilot pump is stopped. The soil improvement machine provided with the excavating means according to claim 2 or 3, wherein the machine is configured to be switched. 7. The soil improvement machine with excavating means according to claim 6, wherein said switching valve valve is configured to switch in conjunction with a direction switching valve for controlling operation of said agitation hydraulic motor. .