JP2022092343A - Rod rotation drive device and ground improvement machine - Google Patents

Abstract

To provide a ground improvement machine equipped with a rod rotation drive device and a rod rotation drive device capable of reliably gripping a rod and suppressing runout of an upper part of the rod.SOLUTION: In a rod rotation drive device 15 provided so as to be able to move up and down along a leader installed at a front of a base machine, the rod rotation drive device includes a drive device main body 25 rotatably provided with a drive shaft 24 having a rod insertion hole 24a through which the rod is inserted, and a pair of upper and lower rod chuck mechanisms 26 rotatably provided on the drive shaft. Further, the drive shaft has a gear 32 that transmits a rotational driving force to an intermediate portion in the rod axial direction. The pair of upper and lower rod chuck mechanisms are provided at the upper and lower ends of the drive shaft at intervals close to equal intervals from the gears.SELECTED DRAWING: Figure 2

Description

The present invention relates to a rod rotation drive device and a ground improvement machine, and more particularly to a rod rotation drive device provided so as to be able to move up and down along a reader erected in front of a base machine, and a ground improvement machine provided with the device.

Conventionally, in a rod rotation drive device (auger) used for a ground improvement machine, a square shaft portion provided on a rod can be inserted and engaged with a drive device main body equipped with a rotation drive source such as a hydraulic motor or a speed reducer. A rod rotation drive device is known in which a rod rotating portion (output shaft) having a square hole and a chuck plate that can be engaged with a groove portion in the circumferential direction provided at the lower portion of the square shaft portion are integrally rotatable. .. The chuck plate is engaged by the force of the spring to fix the rod to the rod rotating portion, and this fixing is released by the receiving portion of the cone-shaped chuck release member provided with the conical cone-shaped chuck release member on the chuck plate. It is a structure that is press-fitted and the chuck plate is pushed and expanded against the force of the spring (see Patent Document 1).

The engaging groove structure having such a chuck plate has a problem that the position for chucking the rod is limited due to the structure. For this reason, a rod rotation drive device having a mechanism capable of chucking a rod at an arbitrary position by a wedge member that appears and disappears in the radial direction has been developed. The wedge member has a structure in which a tightening force is generated by a disc spring and the disc spring is flexed by a hydraulic cylinder to release the rod (see Patent Document 2).

Japanese Unexamined Patent Publication No. 7-189576 Japanese Patent No. 6316220

In recent years, in small ground improvement machines, it is required to increase the rotational torque and thrust of the rod rotation drive device in response to the needs for high output and increase in 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 drops, and sufficient thrust is obtained. There was a problem that it could not be obtained. In addition, if the length of the rod is longer than that of the leader, the rod protruding above the rod rotation drive device swings and precession occurs, which reduces the durability of the rod and the drive device main body and its peripheral parts. Was at risk of being damaged.

Therefore, an object of the present invention is to provide a ground improvement machine provided with a rod rotation drive device and a rod rotation drive device capable of reliably gripping the rod and suppressing the runout of the upper portion of the rod.

In order to achieve the above object, the rod rotation drive device of the present invention is a rod rotation drive device provided so as to be able to move up and down along a reader erected at the front of the base machine, and the rod rotation drive device is a rod. It is characterized by including a drive device main body rotatably provided with a drive shaft having an insertion hole through which the rod is inserted, and a pair of upper and lower rod chuck mechanisms rotatably provided on the drive shaft.

Further, the pair of upper and lower rod chuck mechanisms are characterized in that they are provided at the upper and lower end portions of the drive shaft. Further, the drive shaft has a gear that transmits a rotational driving force to an intermediate portion in the rod axial direction, and the pair of upper and lower rod chuck mechanisms are provided at intervals close to equal intervals from the gear. It is characterized by that.

Further, the rod chuck mechanism is provided with a plurality of wedge members arranged facing the outer peripheral surface of the rod and on the outer side in the rod radial direction of the wedge member, and is a taper that comes into contact with the inclined surface of the outer surface of the wedge member. The wedge member is provided with a surface so that the inclined surface and the tapered surface can be moved inward in the radial direction of the rod by being pressed in the axial direction of the rod. Further, the pair of upper and lower rod chuck mechanisms are characterized in that the inclined surfaces of the outer surface of the wedge member are provided vertically symmetrically so that one faces upward and the other faces downward.

Further, the ground improving machine of the present invention is characterized by including the rod rotation driving device, and further, the rod has a flat surface portion formed by cutting out an even number of points on the outer circumference of a circular cross section at equal intervals in the circumferential direction. The plurality of rust members are characterized by having the same number of rust members as the plane portion arranged so as to face the plane 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 a long rod having a large protrusion amount from the upper surface of the drive device main body can be stably gripped. It can suppress the runout of the upper part of the rod. Further, since the upper and lower rod chuck mechanisms are provided at the upper and lower ends of the drive shaft, the long rods can be stably and reliably gripped by the upper and lower rod chuck mechanisms that are separated from each other as much as possible.

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

In particular, the inclined surface of the outer surface of the wedge member in the upper and lower rod chuck mechanism has a vertically symmetrical shape so that one side faces upward and the other side faces downward, so that the wedge effect can be obtained in either the pushing direction or the pulling direction of the rod. It is enhanced and the rod and the drive shaft can be more firmly integrated.

Further, since the rod mounted on the rod rotation drive device has a flat surface portion formed by cutting out the outer circumference of the circular cross section at four points at equal intervals in the circumferential direction, four rusts facing each plane having a four-sided width are formed. The rod can be stably chucked by the member to cope with a larger rotational torque and thrust. Moreover, since the mud adhering to the outer peripheral surface of the rod can be easily cleaned, the frictional force between the rod and the wedge member, which may occur in the conventional hexagonal cross-sectional structure, is prevented from decreasing, and the required rotational torque and thrust are required. Can be reliably transmitted to the rod.

It is a side view of the ground improvement machine to which the rod rotation drive device which shows the 1st embodiment example of this invention is applied. Similarly, it is a front sectional view of a rod rotation drive device. It is sectional drawing front view of the main part which shows the chuck state and the chuck release state of a rod. It is sectional drawing of the main part which shows the chuck state and the chuck release state of a rod. It is a front view of the rod rotation drive device which shows the 2nd Embodiment example of this invention. It is a circuit diagram which also shows the hydraulic circuit which operates a chuck cylinder.

1 to 4 show an example of a first embodiment in which the rod rotation drive device of the present invention is applied to a ground improvement machine. As shown in FIG. 1, in the ground improvement machine 11, a leader 13 is erected on the front portion of a base machine 12 provided with a traveling portion for crawler running, and the leader 13 is supported by a backstay 14. A rod rotation drive device (auger) 15 is connected to a pair of left and right guide pipes 13a provided along the longitudinal direction of the leader 13 via a guide give 16, and a chain spanned in the longitudinal direction of the leader 13. It is provided so as to be able to move up and down by 13b. Further, a lower guide 18 for guiding the rod 17 rotated by the rod rotation driving device 15 is provided in the lower portion of the reader 13.

The rod 17 is a pipe-shaped rod having a flow path of the ground improving agent inside, and is formed to be longer than the leader 13 by connecting a plurality of rods, and has an excavation blade 19a and a stirring blade 19b at the lower end. A provided excavation head 19 is provided. Further, as shown in FIG. 4, the outer periphery of the rod 17 is provided with a flat surface portion 17a formed by cutting out the outer periphery of the circular cross section at four points at equal intervals in the circumferential direction over the entire length, and the four points are flat surfaces. The four-plane width dimension including 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 formed in a substantially curved surface shape in which the region formed by the arc curved surface portion 17b is largely occupied and substantially no angular portion is generated.

Further, a swivel joint 21 for introducing a ground improving agent from an injection hose (grout hose) 20 is provided at the upper end of the rod 17, and one end of a detent rod 22 for preventing the swivel joint 21 from rotating is driven by rod rotation. It is fixed to the device 15 and the other end is attached to the attachment member 23 provided at 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 held by the rod rotation drive device 15. , The injection hose 20 is connected to the swivel joint 21 at the upper end of the rod 17 (FIG. 1). In this work start state, the rod 17 is rotationally driven and lowered along the leader 13, and the ground improving agent sent through the rod 17 is sprayed from the tip of the excavation head 19 into the excavation hole to drive the excavation head. The earth and sand excavated by the excavation blade 19a of 19 and the ground improving agent are mixed by the stirring blade 19b.

When the rod rotation drive device 15 reaches the lower end portion of the reader 13, the rod rotation drive device 15 that has released the gripping of the intermediate portion is raised, and the grip is changed so that the upper portion is gripped. At this time, in order to fix the rod 17 at that position, the rod 17 is gripped by the fixing means of the lower guide 18. 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 being rotationally driven again, and the earth and sand excavated by the excavation blade 19a and the ground improving agent are mixed by the stirring blade 19b. do. Then, after the excavation head 19 is lowered to a predetermined depth, the excavation head 19 is pulled up in the reverse procedure to complete the ground improvement work.

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

The rod rotation drive device 15 includes a drive device main 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 release mechanisms 27, 27 corresponding to the rod chuck mechanisms 26, 26, and two rotary drive hydraulic motors 29, 29 connected to the deceleration mechanism 28 in the drive device main body 25 are provided. There is. Although not shown, each mechanism is provided with a dustproof / waterproof seal structure and a greasing structure in consideration of maintainability.

The drive shaft 24 has a length similar to the height (total height) of the mounting portion 30 of the rod rotation drive device 15, and both end portions (upper and lower end portions) form a symmetrical shape with a thick intermediate portion interposed therebetween. It is formed in a cylindrical shape and is rotatably provided in the housing (gear case) 25a of the drive device main body 25 via the upper and lower bearings 31 and 31. With the rod 17 inserted through the rod insertion hole 24a and the upper and lower rod chuck mechanisms 26 and 26 being operated to grip the outer periphery of the rod 17, the gear 32 attached to the outer periphery of the intermediate portion of the drive shaft 24 and the rotary drive By meshing with the gear 34 driven by the rotary shaft 33 of the hydraulic motor 29, the rotation of the rotary drive hydraulic motor 29 is transmitted to the drive shaft 24 to rotate the rod 17.

The pair of upper and lower rod chuck mechanisms 26, 26 are vertically separated from the gear 32 in the intermediate portion at an interval close to equal intervals at the upper end and the lower end of the drive shaft 24 so as not to apply an excessive load to the drive shaft 24. It is provided and has the same components, but has a vertically symmetrical shape in which the mounting directions differ from each other by 180 degrees in the rod axial direction. The corresponding upper and lower pairs of chuck release mechanisms 27 and 27 have the same components, but have a vertically symmetrical shape in which the mounting directions differ by 180 degrees in the rod axial direction. Therefore, the specific configuration and operation of the mechanisms 26 and 27, which are designed to be common to the upper and lower parts, will be described by taking up the lower end side.

As shown in FIGS. 3 and 4, the rod chuck mechanism 26 has four wedge members 35 supported by a cylindrical body 24b which is a lower end portion of the drive shaft 24 and a guide hole 24c provided in the cylindrical body 24b. A cylindrical slide member 36 provided on the outer side of the wedge member 35 in the radial direction of the rod, which comes into contact with the outer surface of the wedge member 35 to guide the wedge member 35 inward in the radial direction of the rod, and the slide member 36 as a rod shaft. It is composed of a spring member 37 that is urged upward in the direction.

The cylindrical body 24b has a rod insertion hole 24a inside, and four square guide holes 24c for supporting the wedge member 35 so as to be movable in the radial direction of the rod are formed on the side wall at equal intervals. The inner surface of each wedge member 35 is arranged so that the inner surface on the rod side faces the outer peripheral surface of the rod 17, and the outer surface on the opposite rod side is downwardly inclined inward in the rod radial direction from the upper end to the lower end in the side view. It has a substantially trapezoidal shape 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 an urging means for urging the wedge member 35 outward in the radial direction of the rod.

The slide member 36 is provided with a shaft insertion hole 36a for inserting the cylindrical body 24b in the central portion (FIG. 2), and the shaft insertion hole 36a is inclined according to the arrangement of each wedge member 35. A tapered surface 36b having substantially the same slope as the inclined surface 35a in contact with the surface 35a is partially formed.

The spring member 37 is composed of six disc springs 37a stacked in the rod axial direction, and is arranged between the ring-shaped support member 38 provided at the lower end of the cylindrical body 24b and the lower end of the slide member 36. As a result, the slide member 36 is urged upward in the rod axial direction. A ring-shaped receiving plate 40 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 covering the spring member 37 is provided on the lower side of the peripheral edge of the receiving plate 40. It is provided.

The chuck release mechanism 27 is attached to a set of two chuck cylinders (the opposite side is not shown) 39 and the tip of the piston rod 39a of the chuck cylinder 39, which are arranged opposite to each other on the lower end surface of the drive device main body 25. It is composed of a holding plate 42 to be pressed and the receiving plate 40. The presser plate 42 is provided so as to be able to move up and down in the rod axial direction by expanding and contracting the piston rod 39a of the chuck cylinder 39, and is formed in a ring shape in the center through which the slide member 36 can be inserted. In the reduced state of the chuck cylinder 39, the holding plate 42 and the receiving plate 40 are vertically separated from each other. When the piston rod 39a of the chuck cylinder 39 is extended, the pressing plate 42 abuts on the upper surface of the receiving plate 40 while resisting the urging 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 way is a rod inserted into the drive shaft 24 by simultaneously expanding or contracting a total of four chuck cylinders 39 provided in pairs at the upper and lower ends of the drive shaft 24. 17 chucks and their release are performed.

At the time of rod chucking, the flat surface portion 17a of the rod 17 and the wedge member 35 are aligned in the rotational direction according to the insertion of the rod 17, and then chucked by surface contact with each other. Specifically, as shown in FIGS. 3A and 4A, the chuck cylinder 39 is reduced, and the slide member 36 urged 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 rod axial direction. As a result, the four wedge members 35 arranged to face the flat surface portion 17a of the rod 17 move inward in the radial direction of the rod at the same time, and chuck the rod 17.

Here, since the configuration on the upper end side is a symmetrical shape in which the configuration on the lower end side is inverted upside down, the slide member 36 urged 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 rod axial direction. As a result, the four wedge members 35 arranged to face the flat surface portion 17a of the rod 17 move inward in the radial direction of the rod at the same time, and chuck the rod 17.

On the other hand, when the chuck cylinder 39 is extended and the chuck is released, the slide member 36 moves downward in the rod axial direction as shown in FIGS. 3 (B) and 4 (B), and the slide member 36 is pressed against the wedge member 35. Is weakened. As a result, the four wedge members 35 are simultaneously moved outward in the rod radial direction by the urging force of the urging means, and the chuck of the rod 17 is released. This effect is the same for the configuration on the upper end side.

In such a vertically symmetrical rod chuck mechanism 26, 26, the rod chuck mechanism 26, 26 also rotates integrally in response to the rotation of the rod 17 during construction, and the rod chuck mechanism 26, 26 has 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, resulting in wedges on the upper end side. The pressing of the member 35 is strengthened. That is, the wedge effect in the configuration on the upper end side is remarkably obtained, and the surface pressure acting on the flat surface portion 17a of the rod 17 is increased. On the other hand, a downward force (reaction force) acts in the pulling 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, resulting in wedges on the lower end side. The pressing of the member 35 is strengthened. That is, the wedge effect in the configuration on the lower end side is remarkably obtained, and the surface pressure acting on the flat surface portion 17a of the rod 17 is increased.

As described above, according to the first configuration of the present invention, since the rod rotation drive device 15 includes a pair of upper and lower rod chuck mechanisms 26, 26 that rotate integrally with the drive shaft 24, the rod rotation drive device 15 is provided from the upper surface of the drive device main body 25. Even a long rod with a large protrusion can be stably gripped, and the runout of the upper part of the rod can be suppressed. Further, since the upper and lower rod chuck mechanisms 26 and 26 are provided at the upper and lower ends of the drive shaft 24, the upper and lower rod chuck mechanisms 26 and 26 separated from each other as much as possible to stably and reliably grip the long rod. be able to.

Further, since the upper and lower rod chuck mechanisms 26 and 26 are separated from the power transmission gear 32 at close intervals, not only the rotational torque is transmitted to the rod 17 in a well-balanced manner, but also the bearing housing for accommodating the gear 32 and the like. Since no unreasonable load is applied to the drive device body 25, it is advantageous for improving the rigidity and durability of the drive device main body 25. In addition, since the rod chuck mechanism 26 includes a plurality of wedge members 35 that move in the rod radial direction, the rod 17 can be chucked at an arbitrary position in the length direction as in the rod rotation drive device of Patent Document 2. Can be done.

In particular, the inclined surface 35a on the outer surface of the wedge member 35 in the upper and lower rod chuck mechanisms 26 and 26 has a vertically symmetrical shape so that one faces upward and the other faces downward, so that the rod 17 is in the pushing direction and the pulling direction. In either case, the wedge effect is enhanced, and the rod 17 and the drive shaft 24 can be more firmly integrated.

Further, since the rod 17 mounted on the rod rotation drive device 15 has a flat surface portion 17a formed by cutting out the outer periphery of the circular cross section at four points at equal intervals in the circumferential direction, the rod 17 faces each of the four planes. The rod 17 can be stably chucked by the four rust members 35 to cope with a larger rotational torque and thrust. Moreover, since the mud adhering to the outer peripheral surface of the rod 17 can be easily cleaned, it is possible to prevent a 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 perform the necessary rotation. Torque and thrust can be reliably transmitted to the rod.

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

In the rod rotation drive device 50 in this embodiment, as in the above embodiment, a pair of upper and lower rod chuck mechanisms 53, 53 provided with a plurality of wedge members 52 are integrally rotatable at the upper and lower ends of the drive shaft 51. In particular, a hydraulic method is adopted in which the chuck state of the rod 17 is replaced with the elastic force of the spring member and is held by the hydraulic pressure of the chuck cylinder 54.

The drive shaft 51 has a length sufficient to penetrate the drive device main body 25 of the rod rotation drive device 50, and both end portions (upper and lower end portions) are formed in a symmetrical tubular shape with the intermediate portion interposed therebetween to drive. It is rotatably provided in the housing 25a of the apparatus main body 25 via the upper and lower bearings 31 and 31. The pair of upper and lower rod chuck mechanisms 53, 53 are provided vertically separated from each other at the upper end and the lower end of the drive shaft 51, and although the components are the same, the mounting orientation of the drive shaft 51 is 180 degrees in the rod axial direction. It has a different vertically symmetrical shape. Therefore, the specific configuration and operation of the rod chuck mechanism 53, in which the upper and lower parts are standardized, will be described by taking up the lower end side.

The rod chuck mechanism 53 is provided with four wedge members 52 arranged facing the outer peripheral surface of the rod 17 and outside the wedge member 52 in the rod radial direction, specifically, on the inner peripheral side of the lower end portion of the drive shaft 51. It is provided with a tapered surface 51a that comes into contact with the inclined surface 52a on the outer surface of the wedge member 52. The inner surface of each wedge member 52 is arranged so that the inner surface on the rod side faces the flat surface portion 17a of the rod 17, and the outer surface on the opposite rod side is upwardly inclined outward in the rod radial direction from the upper end to the lower end in the side view. It has a substantially triangular cross section having an inclined surface 52a of. Further, the tapered surface 51a has an upper end continuous with the lower end of the rod insertion hole 51b and has substantially the same slope as the inclined surface 52a in contact with the inclined surface 52a of each wedge member 52.

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

The outer frame member 59 and the drive 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 of and behind the chuck cylinders 54, 54. There is. The chuck cylinder 54 is a reactive hydraulic cylinder capable of supplying hydraulic oil to both sides of the piston, and the bottom portion of the cylinder tube 54a is fixed (directly attached) to the lower surface of the housing 25a of the drive device main body 25, and the tip of the piston rod 54b is attached. The portion is connected to the outer frame member 59 via the support pin 62.

In such a link type rod chuck mechanism 53, the inclined surface 52a of the wedge member 52 and the tapered surface 51a of the drive shaft 51 overlap each other in the vertical direction even when the chuck cylinder 54 is maximally extended, and the spring incorporated in the link member 55. (Not shown) urges the wedge member 52 outward in the radial direction of the rod. 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 the rod 17 inserted into the rod insertion hole 51b while maintaining the engaged state with the tapered surface 51a at the time of maximum extension. It is located away from the outer peripheral surface.

In the rod chuck mechanism 53 configured in this way, when the chuck cylinder 54 is reduced to chuck, the wedge member 52 that has moved upward is inserted between the tapered surface 51a of the drive shaft 51 and the flat surface portion 17a of the rod 17. The tapered surface 51a presses the upward inclined surface 52a of the wedge member 52 in the rod axial direction. As a result, the four wedge members 52 move inward in the radial direction of the rod at the same time to chuck the rod 17 (FIG. 5). On the other hand, when the chuck cylinder 54 is extended and the chuck is released, the wedge member 52 moves downward in the rod axial direction, and the pressing against the wedge member 52 in the rod radial direction is weakened. As a result, the four wedge members 52 move outward in the radial direction of the rod at the same time, and the chuck of the rod 17 is released. This effect is the same for the configuration on the upper end side.

By the way, when the rod 17 is chucked for a long time by the operation of the chuck cylinder 54, the hydraulic oil may gradually leak from the valve or the like of the hydraulic circuit with the passage of time, and the holding pressure of the chuck cylinder 54 may decrease. Therefore, as shown in FIG. 6, the hydraulic circuit 63 that operates the chuck cylinder 54 is provided with an accumulator (accumulator) 64 to support pressure holding during chucking.

The hydraulic circuit 63 includes a pilot check valve 65 capable of opening and closing the flow path between the operation valve (not shown) and the chuck cylinder 54, and the flow path connecting the pilot check valve 65 and the chuck cylinder 54. The chuck cylinder gripping flow path 66 operates (reduces) the chuck cylinder 54 in the direction of chucking the rod 17 with hydraulic oil of a predetermined pressure, and the chuck cylinder 54 operates (extends) the chuck cylinder 54 in the direction of releasing the chuck. It is provided with an open flow path 67. The accumulator 64 is a device that converts hydraulic pressure energy into pressure energy of a gas such as nitrogen gas and stores the pressure, 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 shrinks, and the rod 17 is chucked by the movement of the wedge member 52 accompanying this. At this time, a part of the hydraulic oil also flows into and is stored in the accumulator 64. Then, when the operation valve is returned to the neutral position, the hydraulic oil in the chuck cylinder 54 is sealed by the closing action of the pilot check valve 65, and the oil chamber on the rod side of the chuck cylinder 54 is sealed by the accumulator 64's accumulator action (hydraulic pressure release). Is held at a predetermined pressure. In this case, the chuck cylinder open flow path 67 functions as a return flow path in response to 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 oil chamber on the bottom side of the chuck cylinder 54 through the chuck cylinder open flow path 67, the piston rod 54b is extended, and the chuck of the rod 17 is released by the movement of the wedge member 52 accompanying this. Then, when the operation valve is returned to the neutral position, the hydraulic 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 flow path 66 functions as a return flow path 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.

Even in such a second configuration, the same effect as when the spring member 37 of the first configuration is used can be exhibited, and further, in the case of this embodiment, the chuck of the rod 17 is directly hydraulically pressed. Therefore, the rod 17 can be strongly chucked. Moreover, due to the accumulator action of the accumulator 64, the oil chamber on the rod side of the chuck cylinder 54 is held at the pressure at the time of chucking, and the chuck state of the rod 17 does not loosen. Further, when the chuck is released, hydraulic pressure is supplied to the oil chamber on the bottom side of the chuck cylinder 54, so that the chuck can be released by obtaining a cylinder propulsive force larger than that at the time of chucking. Therefore, even in a state where the wedge member 52 strongly bites into the wedge member 52 due to the action of the pushing force and the pulling force, it is easy to release the wedge member 52.

The present invention is not limited to the above-mentioned examples, and the rod rotation drive device may have a configuration in which a rod chuck mechanism is provided at the upper and lower ends of the drive shaft to increase the support points of the rod. The spacing between the support points can also be changed as appropriate. In addition, the cross-sectional shape of the rod is basically formed in a circular cross-section that is easy to manufacture in this embodiment, but if the conventional polygonal cross-sectional shape is used, the number of wedge members should be increased or decreased accordingly. Can be done. Further, in the configuration for supporting the pressure holding at the time of chucking, a supply circuit other than the accumulator can be provided in the hydraulic circuit.

11 ... Ground improvement machine, 12 ... Base machine, 13 ... Leader, 13a ... Guide pipe, 13b ... Chain, 14 ... Backstay, 15 ... Rod rotation drive device, 16 ... Guide give, 17 ... Rod, 17a ... Flat part, 17b ... Arc curved surface, 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 body, 25a ... Housing, 26 ... Rod chuck mechanism, 27 ... Chuck release mechanism, 28 ... Deceleration mechanism, 29 ... Rotational drive hydraulic pressure Motor, 30 ... Mounting part, 31 ... Bearing, 32 ... Gear, 33 ... Rotating shaft, 34 ... Gear, 35 ... Rabbit member, 35a ... Inclined surface, 36 ... Slide member, 36a ... Shaft insertion hole, 36b ... Tapered surface, 37 ... Spring member, 37a ... Countersunk spring, 38 ... Support member, 39 ... Chuck cylinder, 39a ... Piston rod, 40 ... Receiving plate, 41 ... Cover cylinder, 42 ... Presser plate, 50 ... Rod rotation drive device, 51 ... Drive Shaft, 51a ... Tapered surface, 51b ... Rod insertion hole, 52 ... Rabbit 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 cylinder, 62 ... Support pin, 63 ... Hydraulic circuit, 64 ... Accumulator, 65 ... Pilot check valve, 66 ... Chuck Cylinder gripping flow path, 67 ... Chuck cylinder open flow path

Claims (7)

It is a rod rotation drive device that can be raised and lowered along a reader installed at the front of the 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 rotatably provided on the drive shaft. A rod rotation drive device characterized by being The rod rotation drive device according to claim 1, wherein the pair of upper and lower rod chuck mechanisms are provided at the upper and lower ends of the drive shaft. The drive shaft has a gear that transmits a rotational driving force to an intermediate portion in the rod axial direction, and the pair of upper and lower rod chuck mechanisms are provided at intervals close to equal intervals from the gear. The rod rotation drive device according to claim 1 or 2, wherein the rod rotation drive device is characterized. The rod chuck mechanism includes a plurality of wedge members arranged facing the outer peripheral surface of the rod, and a tapered surface provided on the outer side of the wedge member in the radial direction of the rod and in contact with an inclined surface on the outer surface of the wedge member. Equipped with
The wedge member is any one of claims 1 to 3, wherein the inclined surface and the tapered surface are provided so as to be movable inward in the radial direction of the rod by being pressed in the rod axial direction. The rod rotation drive according to description. The rod according to claim 4, wherein the pair of upper and lower rod chuck mechanisms are provided vertically symmetrically so that one of the inclined surfaces of the outer surface of the wedge member faces upward and the other faces downward. Rotational drive. A ground improvement machine comprising the rod rotation drive device according to any one of claims 1 to 3. The ground improvement machine provided with the rod rotation drive device according to claim 4 or 5, wherein the rod has a flat surface portion formed by cutting out an even number of outer circumferences of a circular cross section at equal intervals in the circumferential direction. The wedge member is the same number of wedge members as the flat surface portion arranged to face the flat surface portion.

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