JP7219257B2 - Rod rotary drive device and ground improvement machine - Google Patents

Description

TECHNICAL FIELD The present invention relates to a rod rotation drive device and a ground improvement machine, and more particularly, to a rod rotation drive device that can be moved up and down along a leader erected on the front part of a base machine, and a ground improvement machine equipped with the device.

Conventionally, in a rod rotation drive device (auger) used in a ground improvement machine, a square shaft portion provided on a rod can be inserted and engaged with a drive device body equipped with a rotary drive source such as a hydraulic motor or a reduction gear. A rod rotation driving device is known that includes a rod rotating part (output shaft) having a square hole and a chuck plate that can be engaged with a circumferential groove part provided in the lower part of the square shaft part so as to rotate integrally therewith. . The chuck plate is engaged by the force of a spring to fix the rod to the rod rotating portion, and the release of this fixation is performed by a cone-shaped chuck release member receiving portion provided on the chuck plate. This structure is performed by press-fitting and expanding the chuck plate against the force of the spring (see Patent Document 1).

The engagement groove structure having such a chuck plate has a problem that the position for chucking the rod is limited due to its structure. For this reason, a rod rotation drive device has been developed which has a mechanism for chucking a rod at an arbitrary position by means of a wedge member that protrudes and retracts in the radial direction. The wedge member has a structure in which a conical spring generates a clamping force and a hydraulic cylinder bends the conical spring to release the rod (see Patent Document 2).

JP-A-7-189576 Japanese Patent No. 6316220

In recent years, small-sized soil improvement machines are required to increase the rotational torque and thrust of the rod rotation drive device in response to the needs for high output and increased excavation length. However, in the rod chuck mechanism described in Patent Document 2, although there is a degree of freedom in the gripping position of the rod, when mud adheres to the outer peripheral surface of the rod, the frictional force between the rod and the wedge member decreases, resulting in insufficient thrust. The problem was that I didn't get it. In addition, if the length of the rod is longer than the leader, the rod that protrudes upward from the rod rotation driving device will swing and cause a whirling motion, which will reduce the durability of the rod and cause damage to the main body of the driving device and its surroundings. was likely to be damaged.

Therefore, an object of the present invention is to provide a rod rotation drive device and a ground improvement machine equipped with the rod rotation drive device that can reliably grip the rod and suppress the shake of the upper part of the rod.

In order to achieve the above object, the rod rotation driving device of the present invention is a rod rotation driving device provided so as to be able to move up and down along a leader erected in front of a base machine, wherein the rod rotation driving device comprises a rod and a pair of upper and lower rod chuck mechanisms rotatably provided on the drive shaft , wherein the rod chuck mechanism includes the rod a plurality of wedge members arranged to face the outer peripheral surface of the wedge member; The inclined surface and the tapered surface are provided movably inward in the rod radial direction by being pressed in the axial direction of the rod. The pair of upper and lower rod chuck mechanisms are characterized in that they are vertically symmetrically provided so that one faces upward and the other faces downward, and chucks the rods at the same time .

Further, the pair of upper and lower rod chuck mechanisms are provided at the upper and lower ends of the drive shaft. Further, the drive shaft has a gear that transmits a rotational driving force to an intermediate portion in the axial direction of the rod, and the pair of upper and lower rod chuck mechanisms are spaced apart from the gear at a nearly equal interval. It is characterized by

Further, the ground improvement machine of the present invention is characterized by comprising the rod rotation drive device, and further, the rod has a flat portion formed by notching the outer circumference of the circular cross section at even intervals in the circumferential direction. The plurality of wedge members are provided over the entire length, and the plurality of wedge members are the same number of wedge members as the flat portions arranged to face the flat portion.

According to the present invention, since the rod rotation drive device is provided with a pair of upper and lower rod chuck mechanisms that rotate integrally with the drive shaft, even long rods protruding from the upper surface of the main body of the drive device can be stably gripped. It is possible to suppress the swing of the upper part of the rod. In addition, since the upper and lower rod chuck mechanisms are provided at the upper and lower ends of the drive shaft, the long rod can be stably and reliably gripped by the upper and lower rod chuck mechanisms separated from each other as much as possible.

In addition, since the upper and lower rod chuck mechanisms are separated from the power transmission gears at nearly equal intervals, not only is the rotational torque transmitted to the rods in a well-balanced manner, but also the bearing housing that houses the gears is subjected to an unreasonable load. Therefore, it is advantageous for improving the rigidity and durability of the main body of the driving device. In addition, since the rod chuck mechanism has a plurality of wedge members that move in the rod radial direction, it is possible to chuck the rod at any position in the length direction as in the rod rotation drive device of Patent Document 2.

In particular, since the inclined surfaces of the outer surfaces of the wedge members in the upper and lower rod chuck mechanisms are vertically symmetrical so that one faces upward and the other faces downward, the wedge effect is achieved in both the pushing direction and the pulling out direction of the rod. and the rod and the drive shaft can be more strongly integrated.

In addition, since the rod mounted on the rod rotation driving device has four planar portions formed by notching the outer circumference of the circular cross section at equal intervals in the circumferential direction, four wedges facing each of the four plane width planes are provided. The rod can be stably chucked by the member, and greater rotational torque and thrust can be handled. Moreover, since it is easy to clean the mud adhering to the outer peripheral surface of the rod, it prevents the reduction of the frictional force between the rod and the wedge member, which may occur in the conventional hexagonal cross-section structure, and the necessary rotational torque and thrust are prevented. can be reliably transmitted to the rod.

BRIEF DESCRIPTION OF THE DRAWINGS It is a side view of the ground improvement machine to which the rod rotation drive which shows the example of a 1st form of this invention is applied. Similarly, it is front sectional drawing of a rod rotation drive. It is a principal part cross-sectional front view which shows the chuck|zipped state of a rod, and a chuck|chuck release state. FIG. 4 is a cross-sectional plan view of a main part showing a chucked state and a chuck-released state of a rod; It is a front view of the rod rotation drive which shows the example of the 2nd form of this invention. FIG. 4 is a circuit diagram showing a hydraulic circuit that similarly operates the chuck cylinder;

1 to 4 show a first embodiment in which the rod rotation drive device of the present invention is applied to a soil improvement machine. As shown in FIG. 1 , the soil improvement machine 11 has a leader 13 erected at the front of a base machine 12 having a crawler traveling section, and the leader 13 is supported by a backstay 14 . A rod rotation driving device (auger) 15 is connected via a guide gib 16 to a pair of left and right guide pipes 13a provided along the longitudinal direction of the leader 13, and a chain stretched over the leader 13 in the longitudinal direction. 13b to be able to move up and down. A lower guide 18 is provided below the leader 13 to guide the rod 17 rotated by the rod rotation drive device 15 .

The rod 17 is a pipe-shaped one having a soil improvement agent flow path inside, and is formed longer than the leader 13 by connecting a plurality of rods, and has an excavating blade 19a and a stirring blade 19b at the lower end. A drilling head 19 is provided. Further, as shown in FIG. 4, the outer periphery of the rod 17 is provided with flat portions 17a which are formed by cutting out four portions of the outer periphery of a circular cross section at equal intervals in the circumferential direction over the entire length. The four-sided width dimension of the portion 17a is slightly smaller than the outer diameter dimension of the circumferential portion of the circular cross section. As a result, the outer peripheral surface of the rod 17 is largely occupied by the area formed by the arc curved surface portion 17b, and is formed in a substantially curved surface shape with substantially no angular portions.

In addition, the upper end of the rod 17 is provided with a swivel joint 21 that introduces a soil improvement agent from an injection hose (grout hose) 20, and one end of a detent rod 22 that prevents co-rotation of the swivel joint 21 is driven to rotate the rod. It is fixed to the device 15 and the other end is attached to a mounting member 23 provided on the upper end of the rod 17 .

In order to perform ground improvement work using the ground improvement machine 11, the rod 17 is held rotatably and vertically movable by the lower guide 18 while the intermediate portion of the rod 17 is gripped by the rod rotation drive device 15. , an injection hose 20 is connected to a swivel joint 21 at the upper end of the rod 17 (FIG. 1). In this operation start state, the rod 17 is rotated and lowered along the leader 13, and the soil improvement agent sent through the rod 17 is injected from the tip of the excavation head 19 into the excavation hole, thereby The earth and sand excavated by the excavating blade 19a of 19 and the soil improvement agent are mixed by the stirring blade 19b.

When the rod rotation driving device 15 reaches the lower end of the leader 13, the rod rotation driving device 15, which has released the gripping of the intermediate portion, is lifted and re-gripped to grip the upper portion. At this time, the rod 17 is gripped by the fixing means of the lower guide 18 to keep the rod 17 fixed in that position. After switching the gripping position of the rod 17 to the upper side by moving the rod rotation drive device 15, the rod 17 is lowered while rotating again, and the soil excavated by the excavation blade 19a and the soil improvement agent are mixed by the stirring blade 19b. do. Then, after lowering the excavation head 19 to a predetermined depth, the excavation head 19 is pulled up in the reverse order to complete the ground improvement work.

In order to smoothly proceed with such ground improvement work, the rod rotation driving device 15 is required to have a structure that reliably transmits the necessary rotational torque and thrust to the rod 17 . A specific configuration of the rod rotation driving device 15 will be described below with reference to FIGS. 2 to 4. FIG.

The rod rotation drive device 15 includes a drive device body 25 rotatably provided with a drive shaft 24 having a circular rod insertion hole 24a, and a pair of upper and lower rod chuck mechanisms 26, 26 rotatably provided on the drive shaft 24. , a pair of upper and lower chuck releasing mechanisms 27, 27 corresponding to the rod chucking mechanisms 26, 26; there is Although not shown, each mechanism has a dust-proof and waterproof sealing structure, a lubricating structure for ease of maintenance, and the like.

The drive shaft 24 has a length approximately equal to the height (total height) of the mounting portion 30 of the rod rotation drive device 15, and has a symmetrical shape at both ends (upper and lower ends) with a thick intermediate portion interposed therebetween. It is formed in a cylindrical shape and is rotatably provided in a housing (gear case) 25a of the drive device main body 25 via upper and lower bearings 31,31. The rod 17 is inserted through the rod insertion hole 24a, and the upper and lower rod chuck mechanisms 26, 26 are operated to hold the outer circumference of the rod 17. Then, the gear 32 attached to the outer circumference of the intermediate portion of the drive shaft 24 and the rotation drive A gear 34 driven by a rotary shaft 33 of the hydraulic motor 29 is engaged with the rotary drive hydraulic motor 29 to transmit the rotation of the rotary drive hydraulic motor 29 to the drive shaft 24 to rotate the rod 17 .

The pair of upper and lower rod chuck mechanisms 26, 26 are vertically spaced apart from the intermediate gear 32 at the upper and lower ends of the drive shaft 24 at nearly equal intervals so as not to apply an excessive load to the drive shaft 24. Although the components are the same, they have a vertically symmetrical shape in which the mounting directions are different from each other by 180 degrees in the axial direction of the rod. A corresponding pair of upper and lower chuck release mechanisms 27, 27 also have the same component parts, but have a vertically symmetrical shape in which the mounting directions are different from each other by 180 degrees in the axial direction of the rod. Therefore, the specific configuration and action of the mechanisms 26 and 27, which are designed to be common parts on the upper and lower sides, will be described with reference to the lower end portion side.

As shown in FIGS. 3 and 4, the rod chuck mechanism 26 includes a cylindrical body 24b, which is the lower end of the drive shaft 24, and four wedge members 35 supported by guide holes 24c provided in the cylindrical body 24b. and a cylindrical slide member 36 provided outside the wedge member 35 in the rod radial direction and in contact with the outer surface of the wedge member 35 to guide the wedge member 35 inward in the rod radial direction; and a spring member 37 that biases upward.

The cylindrical body 24b has a rod insertion hole 24a inside, and four rectangular guide holes 24c are formed at equal intervals in the side wall thereof for supporting the wedge member 35 so as to be movable in the radial direction of the rod. Each wedge member 35 has a rod-side inner surface facing the outer peripheral surface of the rod 17 , and has a downward-facing surface that is inclined inward in the rod radial direction from the upper end to the lower end in a side view on the outer surface opposite to the rod side. It has a substantially trapezoidal cross section with an inclined surface 35a. Further, a spring (not shown) is provided between the upper end of the wedge member 35 and the outer wall of the cylindrical body 24b as biasing means for biasing the wedge member 35 outward in the rod radial direction.

The slide member 36 is provided with a shaft insertion hole 36a (FIG. 2) through which the cylindrical body 24b is inserted in the central portion thereof. A tapered surface 36b having substantially the same gradient as the inclined surface 35a contacting the surface 35a is partially formed.

The spring member 37 is composed of six disk springs 37a stacked in the axial direction of the rod and arranged between a ring-shaped support member 38 provided at the lower end of the cylindrical body 24b and the lower end of the slide member 36. Thus, the slide member 36 is biased upward in the rod axial direction. A ring-shaped receiving plate 40 that is pressed by a pressing plate 42, which will be described later, is provided on the lower outer periphery of the slide member 36, and a cover cylinder 41 that covers the spring member 37 is provided on the lower side of the peripheral edge of the receiving plate 40. is provided.

The chuck release mechanism 27 is attached to a set of two chuck cylinders (the opposite side is not shown) 39 arranged opposite to the lower end surface of the drive device main body 25 and the tip end of the piston rod 39a of the chuck cylinder 39. and the receiving plate 40. The pressing plate 42 is provided so as to move up and down in the axial direction of the rod by extension and contraction of the piston rod 39a of the chuck cylinder 39, and is formed in a ring shape through which the slide member 36 can be inserted. In the contracted state of the chuck cylinder 39, the pressing plate 42 and the receiving plate 40 are vertically separated from each other. When the piston rod 39a of the chuck cylinder 39 extends, the pressing plate 42 contacts the upper surface of the receiving plate 40 while resisting the biasing force (elastic force) of the spring member 37, and presses the receiving plate 40 downward in the rod axial direction.

The rod rotation drive device 15 configured in this manner simultaneously extends or contracts a total of four chuck cylinders 39 provided in pairs at the upper and lower ends of the drive shaft 24 to extend or contract the rods inserted through the drive shaft 24 . 17 chucks and unclamps are performed.

During rod chucking, the planar portion 17a of the rod 17 and the wedge member 35 are aligned in the rotational direction as the rod 17 is inserted, and then chucked in surface contact with each other. Specifically, as shown in FIGS. 3A and 4A, the chuck cylinder 39 is contracted, and the slide member 36 biased upward in the rod axial direction by the spring member 37 moves upward, The tapered surface 36b of the slide member 36 presses the downward inclined surface 35a of the wedge member 35 in the axial direction of the rod. As a result, the four wedge members 35 arranged to face the flat portion 17a of the rod 17 simultaneously move inward in the rod radial direction to chuck the rod 17 .

Here, since the configuration on the upper end side has a symmetrical shape obtained by vertically inverting the configuration on the lower end side, the slide member 36 biased downward in the rod axial direction by the spring member 37 moves downward and slides. The tapered surface 36b of the member 36 presses the upward inclined surface 35a of the wedge member 35 in the axial direction of the rod. As a result, the four wedge members 35 arranged to face the flat portion 17a of the rod 17 simultaneously move inward in the rod radial direction to chuck the rod 17 .

On the other hand, when the chuck is released by extending the chuck cylinder 39, as shown in FIGS. weakens. As a result, the four wedge members 35 are simultaneously moved outward in the rod radial direction by the biasing force of the biasing means, and the chucking of the rod 17 is released. Such action is the same for the configuration of the upper end portion side.

In such vertically symmetrical rod chuck mechanisms 26, 26, the rod chuck mechanisms 26, 26 rotate integrally with the rotation of the rod 17 during construction, and the rod chuck mechanisms 26, 26 have a pushing force and a pulling force. It takes Then, an upward force (reaction force) acts in the pushing direction, and the frictional force between the tapered surface 36b of the slide member 36 and the upward inclined surface 35a of the wedge member 35 increases, and the wedge on the upper end side The pressing force of the member 35 is strengthened. That is, the wedge effect in the structure of the upper end portion is remarkably obtained, and the surface pressure acting on the flat portion 17a of the rod 17 is increased. On the other hand, a downward force (reaction force) acts in the pull-out direction, and the frictional force between the tapered surface 36b of the slide member 36 and the downward inclined surface 35a of the wedge member 35 increases, and the wedge on the lower end side The pressing force of the member 35 is strengthened. That is, the wedge effect in the structure of the lower end side is remarkably obtained, and the surface pressure acting on the flat portion 17a of the rod 17 is increased.

Thus, according to the first configuration of the present invention, since the rod rotation drive device 15 is provided with a pair of upper and lower rod chuck mechanisms 26, 26 that rotate integrally with the drive shaft 24, the movement of light from the upper surface of the drive device main body 25 Even a long rod with a large amount of protrusion can be stably gripped, and vibration of the upper part of the rod can be suppressed. In addition, since the upper and lower rod chuck mechanisms 26, 26 are provided at the upper and lower ends of the drive shaft 24, the long rod is stably and reliably gripped by the upper and lower rod chuck mechanisms 26, 26 separated from each other as much as possible. be able to.

Furthermore, since the upper and lower rod chuck mechanisms 26, 26 are spaced apart from the power transmission gear 32 at nearly equal intervals, not only is the rotational torque transmitted to the rod 17 in a well-balanced manner, but also the bearing housing housing the gear 32, etc. This is advantageous in improving the rigidity and durability of the driving device main body 25 because no excessive load is applied to the drive device main body 25 . In addition, since the rod chucking mechanism 26 is provided with a plurality of wedge members 35 that move in the rod radial direction, the rod 17 can be chucked at any position in the longitudinal direction as in the rod rotation driving device of Patent Document 2. can be done.

In particular, the inclined surfaces 35a on the outer surfaces of the wedge members 35 in the upper and lower rod chuck mechanisms 26, 26 are symmetrically shaped so that one faces upward and the other faces downward. In any case, the wedge effect is enhanced, and the rod 17 and the drive shaft 24 can be more firmly integrated.

In addition, since the rod 17 mounted on the rod rotation driving device 15 has flat portions 17a formed by notching the outer circumference of the circular cross section at four locations at equal intervals in the circumferential direction, the flat portions 17a are opposed to the four flat surfaces. The rod 17 can be stably chucked by the four wedge members 35, and greater rotational torque and thrust can be handled. Moreover, since it is easy to clean the mud adhering to the outer peripheral surface of the rod 17, it is possible to prevent the decrease in the frictional force between the rod 17 and the wedge member 35, which may occur in the conventional hexagonal cross-sectional structure, and to prevent the required rotation. Torque and thrust can be reliably transmitted to the rod.

5 and 6 show a second embodiment of the rod rotation driving device of the present invention. FIG. 5 is a front view of a rod rotation driving device having a rod chuck mechanism, and FIG. 6 is a hydraulic circuit diagram for operating a chuck cylinder. In the following description, the same reference numerals are given to the same components as those shown in the above-described embodiment, and detailed description thereof will be omitted.

In the rod rotation drive device 50 of this embodiment, a pair of upper and lower rod chuck mechanisms 53, 53 having a plurality of wedge members 52 are provided at the upper and lower ends of the drive shaft 51 so as to be rotatable together, as in the previous embodiment. In particular, a hydraulic system is adopted in which the chucked state of the rod 17 is held by the hydraulic pressure of the chuck cylinder 54 instead of the elastic force of the spring member.

The drive shaft 51 has a length sufficient to pass through the drive device main body 25 of the rod rotation drive device 50, and is formed in a cylindrical shape with both ends (upper and lower ends) having a symmetrical shape with an intermediate portion interposed therebetween. Inside the housing 25a of the apparatus main body 25, it is rotatably provided via upper and lower bearings 31,31. The pair of upper and lower rod chuck mechanisms 53, 53 are vertically spaced apart from each other at the upper and lower ends of the drive shaft 51, and although the components are the same, they are mounted 180 degrees in the axial direction of the rod. They have different vertically symmetrical shapes. Therefore, the specific configuration and action of the rod chuck mechanism 53, which has parts common to the upper and lower parts, will be described with reference to the lower end part side.

The rod chuck mechanism 53 includes four wedge members 52 arranged to face the outer peripheral surface of the rod 17, and provided outside the wedge members 52 in the rod radial direction, specifically, on the inner peripheral side of the lower end portion of the drive shaft 51. and has a tapered surface 51a that contacts the inclined surface 52a on the outer surface of the wedge member 52. As shown in FIG. Each wedge member 52 has an inner surface on the rod side facing the flat portion 17a of the rod 17, and an outer surface on the counter-rod side that is inclined radially outward from the upper end to the lower end of the wedge member 52 in a side view. has a substantially triangular cross-section with an inclined surface 52a. The tapered surface 51a has an upper end continuous with the lower end of the rod insertion hole 51b and has substantially the same gradient as the inclined surface 52a of each wedge member 52 that contacts the inclined surface 52a.

One end (upper end) of a link member 55 is rotatably connected to each wedge member 52 via a support pin 56 , and the other end (lower end) of the link member 55 is connected to the inner frame via a support pin 57 . It is rotatably connected to member 58 . The inner frame member 58 is formed in the center in a ring shape through which the rod 17 can be inserted, and is rotatably provided on the outer frame member 59 coaxial therewith via a bearing 60 .

The outer frame member 59 and the driving device main body 25 are connected via a pair of left and right chuck cylinders 54, 54 and a total of four guide cylinders 61 arranged in front and behind the chuck cylinders 54, 54. there is The chuck cylinder 54 is a double acting hydraulic cylinder capable of supplying hydraulic oil to both sides of the piston. are connected to the outer frame member 59 via support pins 62 .

In such a link type rod chuck mechanism 53, even when the chuck cylinder 54 is fully extended, the inclined surface 52a of the wedge member 52 and the tapered surface 51a of the drive shaft 51 overlap in the vertical direction. (not shown) urges the wedge member 52 outward in the rod radial direction. As a result, the wedge member 52 slides on the tapered surface 51a due to the expansion and contraction of the chuck cylinder 54, and at the time of maximum extension, the rod 17 inserted through the rod insertion hole 51b can be moved while maintaining the state of engagement with the tapered surface 51a. Located away from the outer peripheral surface.

In the rod chuck mechanism 53 configured as described above, the upwardly moved wedge member 52 is inserted between the tapered surface 51a of the drive shaft 51 and the flat portion 17a of the rod 17 when the chuck cylinder 54 is contracted and chucked. The tapered surface 51a presses the upward inclined surface 52a of the wedge member 52 in the axial direction of the rod. As a result, the four wedge members 52 simultaneously move inward in the rod radial direction to chuck the rod 17 (FIG. 5). On the other hand, when the chuck is released by extending the chuck cylinder 54, the wedge member 52 moves downward in the axial direction of the rod, and the pressing against the wedge member 52 in the radial direction of the rod is weakened. As a result, the four wedge members 52 simultaneously move outward in the rod radial direction, and the chuck of the rod 17 is released. Such action is the same for the configuration of the upper end portion side.

When the chuck cylinder 54 is operated to chuck the rod 17 for a long period of time, working oil may gradually leak from the valves of the hydraulic circuit over time, and the holding pressure of the chuck cylinder 54 may decrease. Therefore, as shown in FIG. 6, an accumulator (pressure accumulator) 64 is provided in a hydraulic circuit 63 for operating the chuck cylinder 54 to assist pressure retention during chucking.

The hydraulic circuit 63 includes a pilot check valve 65 capable of opening and closing a flow path between an operation valve (not shown) and the chuck cylinder 54, and a flow path connecting the pilot check valve 65 and the chuck cylinder 54. , a chuck cylinder gripping passage 66 for operating (retracting) the chuck cylinder 54 in the direction of chucking the rod 17 with hydraulic oil of a predetermined pressure, and a chuck cylinder operating (extending) the chuck cylinder 54 in the direction of releasing the chuck. and an open channel 67 . The accumulator 64 is a device that converts hydraulic pressure energy into gas pressure energy such as nitrogen gas and accumulates the pressure energy, and is provided in the chuck cylinder gripping flow path 66 .

When hydraulic oil is supplied to the rod-side oil chamber of the chuck cylinder 54 through the chuck cylinder gripping flow path 66, the piston rod 54b is contracted, and the wedge member 52 moves accordingly, thereby chucking the rod 17. As shown in FIG. At this time, part of the hydraulic oil also flows into the accumulator 64 and is stored therein. When the operation valve is returned to the neutral position, the operating oil in the chuck cylinder 54 is sealed by the closing action of the pilot check valve 65, and the pressure accumulation action (hydraulic pressure release) of the accumulator 64 causes the rod-side oil chamber of the chuck cylinder 54 to is held at a predetermined pressure. In this case, the chuck cylinder release flow path 67 functions as a return flow path upon receiving the operation of the chuck cylinder 54, and the oil discharged from the bottom side oil chamber is returned to the tank.

On the other hand, when hydraulic oil is supplied to the bottom-side oil chamber of the chuck cylinder 54 through the chuck cylinder release passage 67, the piston rod 54b extends, and the wedge member 52 moves accordingly, releasing the chuck of the rod 17. When the operation valve is returned to neutral, the operating oil in the chuck cylinder 54 is sealed by the closing action of the pilot check valve 65 . In this case, the chuck cylinder gripping channel 66 functions as a return channel in response to the operation of the chuck cylinder 54, and the oil discharged from the rod-side oil chamber is returned to the tank.

In the second configuration as described above, the same effect as in the case of using the spring member 37 of the first configuration can be exhibited. Therefore, the rod 17 can be strongly chucked. Moreover, due to the pressure accumulation action of the accumulator 64, the rod-side oil chamber of the chuck cylinder 54 is held at the chucking pressure, so that the chucked state of the rod 17 does not loosen. Further, when releasing the chuck, since hydraulic pressure is supplied to the bottom side oil chamber of the chuck cylinder 54, the chuck can be released by obtaining a greater cylinder driving force than when chucking. Therefore, even if the wedge member 52 is strongly bitten by the pushing force or the pulling force, the wedge member 52 can be easily released.

In addition, the present invention is not limited to the above embodiments, and the rod rotation drive device may have a structure in which rod chuck mechanisms are provided at the upper and lower ends of the drive shaft to increase the number of support points for the rod. The spacing between the supporting points can also be changed as appropriate. In addition, regarding the cross-sectional shape of the rod, in this embodiment, a circular cross-section is formed, which is easy to manufacture. can be done. Furthermore, in the structure for supporting pressure retention during chucking, a replenishment circuit other than the accumulator can be provided in the hydraulic circuit.

DESCRIPTION OF SYMBOLS 11... Soil improvement machine, 12... Base machine, 13... Leader, 13a... Guide pipe, 13b... Chain, 14... Back stay, 15... Rod rotation drive device, 16... Guide gib, 17... Rod, 17a... Flat part, 17b Circular curved surface portion 18 Lower guide 19 Excavation head 19a Excavation blade 19b Stirring blade 20 Injection hose 21 Swivel joint 22 Anti-rotation rod 23 Mounting member 24 Drive shaft , 24a Rod insertion hole 24b Cylindrical body 24c Guide hole 25 Drive device main body 25a Housing 26 Rod chuck mechanism 27 Chuck release mechanism 28 Reduction mechanism 29 Rotary drive hydraulic pressure Motor 30 Mounting portion 31 Bearing 32 Gear 33 Rotating shaft 34 Gear 35 Wedge member 35a Inclined surface 36 Slide member 36a Shaft insertion hole 36b Tapered surface 37... Spring member 37a... Disc spring 38... Support member 39... Chuck cylinder 39a... Piston rod 40... Receiving plate 41... Cover tube 42... Pressing plate 50... Rod rotation drive device 51... Drive Shaft 51a Tapered surface 51b Rod insertion hole 52 Wedge member 52a Inclined surface 53 Rod chuck mechanism 54 Chuck cylinder 54a Cylinder tube 54b Piston rod 55 Link member 56 , 57... Support pin, 58... Inner frame member, 59... Outer frame member, 60... Bearing, 61... Guide tube, 62... Support pin, 63... Hydraulic circuit, 64... Accumulator, 65... Pilot check valve, 66... Chuck Cylinder gripping channel, 67... Chuck cylinder releasing channel

Claims (4)

A rod rotation driving device provided so as to be able to move up and down along a leader erected in front of a base machine,
The rod rotation drive device includes a drive device main body rotatably provided with a drive shaft having an insertion hole through which a rod is inserted, and a pair of upper and lower rod chuck mechanisms provided rotatably integrally with the drive shaft ,
The rod chuck mechanism includes a plurality of wedge members arranged to face the outer peripheral surface of the rod, and a tapered surface provided outside the wedge member in the rod radial direction and in contact with the inclined surface of the outer surface of the wedge member. with
The wedge member is provided movably inward in the rod radial direction by pressing the inclined surface and the tapered surface in the axial direction of the rod,
The pair of upper and lower rod chuck mechanisms are vertically symmetrically provided so that one inclined surface of the outer surface of the wedge member faces upward and the other slopes downward,
The pair of upper and lower rod chuck mechanisms simultaneously chuck the rods.
A rod rotation drive device characterized by: 2. The rod rotation drive device according to claim 1, wherein the pair of upper and lower rod chuck mechanisms are provided at upper and lower end portions of the drive shaft. The drive shaft has a gear that transmits a rotational driving force to an intermediate portion in the axial direction of the rod, and the pair of upper and lower rod chuck mechanisms are spaced apart from the gear at a substantially equal interval. 3. The rod rotation driving device according to claim 1 or 2. A soil improvement machine equipped with the rod rotation drive device according to any one of claims 1 to 3 , wherein the rod has a flat portion formed by notching the outer circumference of the circular cross section at even intervals in the circumferential direction. A ground improvement machine having the same number of wedge members as the number of said flat portions disposed facing said flat portion.

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