JP2007284909A - Turning mechanism and excavator - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide an excavator capable of continuously obtaining the excavation of circular and noncircular cross sections at a low cost while reducing the rotational swing and vibrations of a driving system. <P>SOLUTION: When a rotating shaft 33 is rotated in the counterclockwise direction centering around a fixed center line P by a driving section, an annular shaft 32 engaged with the first outer peripheral section 331 of the rotating shaft is turned in the same direction as the rotating shaft centering around a moving center line G under the state in which the annular shaft 32 is held to a holding member 34. The outer peripheral section 322 of the annular shaft is engaged with the inner peripheral section 311 of a bearing 31, and the annular shaft is revolved in the opposite direction to the rotating shaft in the periphery of the fixed center line P along the inner peripheral section of the bearing. Consequently, an excavating cutter 2 fitted to the annular shaft forms an approximately rectangular locus as a noncircular shape by a rotation and a revolution. Then, the moving center line is conformed to the fixed center line and the annular shaft is moved so that the outer peripheral section is separated from the inner peripheral section of the bearing, and the driving force of the driving section is transmitted to the annular shaft, thus forming a circular locus by the rotation centering around the fixed center line by the excavating cutter fitted to the annular shaft. <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

  The present invention relates to a rotation mechanism that forms circular and non-circular trajectories at the same center, and an excavator that excavates the ground using the rotation mechanism.

  A general excavator is known in which a cutter head is rotated by a rotating mechanism and the ground is excavated by the cutter head. Such an excavator inevitably has a circular cross-section because the cutter head rotates about a predetermined center. However, in tunnel use spaces such as railways and roads, the required cross-sectional shape is often non-circular, and a non-circular railway or road space is constructed within the circular excavation cross-section. . For this reason, since excavation more than utilization space is performed, in addition to requiring a lot of land area, there exists a problem that construction cost increases.

  2. Description of the Related Art Conventionally, for example, there is a square drilling device for forming a square hole in a workpiece by providing a cutting tool on a Rouleau triangle rotating body such as a Rouleau triangle and rotating the Rouleau triangle rotating body (for example, patents) Reference 1).

  In addition, there is an excavator in which a machining member is attached to a machining member rotation support device so as to be rotatable about its center, and the machining member rotation support device is attached to the machining member revolution support device. The processed member is provided with an excavation working surface by providing excavation blades at the apexes of substantially equilateral triangles concentric with the center and inward thereof. The processed member rotation support device is attached to the processed member revolving support device so that the center rotates at a radius ((1/2) / cos30 ° − (1/2)) times one side of the equilateral triangle. is there. And the drive means which revolves 3 times in the direction opposite to the rotation direction while rotating a process member is provided (for example, refer patent document 2).

  In addition, a circular arc centered on each vertex of the regular triangle and having the length of one side as a radius is drawn on the outside of each opposite side, and a cutter having an outline of a Rouleau triangle surrounded by these three circular arcs is defined as a rectangle. There is a rectangular shield method in which excavation is performed by rotating while revolving around the central axis of the shape skin plate. The eccentric distance of the rotation axis of the cutter with respect to the center axis of the skin plate is set so as to satisfy (L / 2) / cos 30 ° − (L / 2) (L: distance between vertices of the Rouleau triangle). The revolution number of the cutter is three times the revolution number, and the revolution direction and the revolution direction are opposite directions (see, for example, Patent Document 3).

  Furthermore, there is a free section shield method in which a main cutter excavates a circular center part of an excavation section and a plurality of planetary cutters excavate an outer peripheral part thereof. The planetary cutter revolves while rotating around the outer periphery of the main cutter as the main cutter rotates. This revolution trajectory can be arbitrarily changed by adjusting the angle of the swing arm provided with the planetary cutter. As a result, various excavation cross-sectional shapes, such as a rectangle, an ellipse, a horseshoe shape, and an egg shape, can be selected at the same center (for example, refer nonpatent literature 1).

JP-A-11-267950 JP-A-1-158196 Japanese Patent No. 2926125 Shield Construction Method Association, “Free Section Shield Construction Method”, [online], searched on September 16, 2005, Internet <URL: http://www.shield-method.gr.jp/pdf_data/jiyu.pdf>

  By the way, when digging into a non-circular, substantially rectangular shape using the rouleau triangle, it is necessary to rotate the rouleau triangle around its center of gravity and revolve the lureau triangle center of gravity around the center of the square. There is.

  In the invention of Patent Document 1, a shaft for transmitting the torque of the motor and a shaft at the center of gravity of the Rouleau triangle rotating body are connected by a universal joint. However, in this configuration, rotational vibration and vibration are generated in the drive transmission system, and in an excavator that requires a larger torque, the universal joint is expensive and the manufacturing cost increases.

  In the invention of Patent Document 2, a revolution device is configured by transmitting torque from a motor to a machining member by a crankshaft. However, cranking causes shearing force and bending moment to the rotating shaft member, which causes rotational vibration and vibration.

  In the invention of Patent Document 3, a revolution drive board is provided at the center of a rectangular skin plate, and a cutter rotation shaft is provided on the revolution drive board. A motor for rotating the revolution drive board and a motor for rotating the cutter rotating shaft are provided. However, since the motor for rotating the cutter rotating shaft is provided on the revolution drive board, it is necessary to design the wiring and pipes after careful examination. Furthermore, it is necessary to synchronize by adjusting the rotation speed and rotation direction of each motor. As a result, the design cost increases.

  As described above, although there is an application for a rotation mechanism that uses the principle of the Rouleau triangle to form a substantially rectangular locus, none of them realizes rational driving. Further, in excavators that require a large torque, a square frame requires a large space in the excavation hole, so a mechanism without a square frame is desired. Furthermore, there is no realization of a rotating mechanism that forms a polygonal locus including a rectangular shape and an excavator using the rotating mechanism, not limited to rectangular excavation.

  In addition, the method of Non-Patent Document 1 corresponds to rectangular or elliptical excavation, but in order to obtain a plurality of planetary cutters that revolve while rotating around the outer periphery of the main cutter as the main cutter rotates, It has a complicated structure using an arm. As a result, there is a problem that the manufacturing cost increases.

  In view of the above circumstances, the present invention provides a rotary mechanism that forms circular and non-circular trajectories at low cost while reducing rotational shake and vibration of a drive system, and circular and non-circular using the rotary mechanism. An object of the present invention is to provide an excavator capable of continuously obtaining excavation of a cross section having a shape.

  In order to achieve the above object, a rotating mechanism according to claim 1 of the present invention includes a fixed bearing having an annular inner periphery centered on a predetermined fixed center line, and a predetermined parallel to the fixed center line. The first rotation position where the outer peripheral portion is engaged with the inner peripheral portion of the bearing is fixed with the inner peripheral portion and the outer peripheral portion around the moving center line. An annular shaft provided so that the movement center line coincides with the center line and the outer peripheral part can be moved to a second rotational position separated from the inner peripheral part of the bearing, and provided so as to be rotatable about the fixed center line. Abutment engagement along the entire circumference of the first outer peripheral portion that abuts and engages with a part of the inner peripheral portion of the annular shaft at the first rotational position and the inner peripheral portion of the annular shaft at the second rotational position. A rotating shaft that is disposed along a fixed center line, a driving unit that rotationally drives the rotating shaft, The engagement between the outer peripheral portion of the annular shaft and the inner peripheral portion of the bearing is maintained while maintaining the engagement between the inner peripheral portion of the annular shaft and the first outer peripheral portion of the rotary shaft when the shaft is in the first rotation position. A holding member for holding the joint, and maintaining or releasing the holding form of the holding member, moving the annular shaft to the first rotational position or the second rotational position, and further rotating the annular shaft according to each rotational position of the annular shaft Rotation mode changing means for moving the shaft along a fixed center line, and an extension line provided at the annular shaft and connecting at least the center and the apex of a Rouleau triangle centered on the moving center line And a blade member.

  The rotating mechanism according to a second aspect of the present invention is characterized in that, in the first aspect, the blade member is formed so as to be extendable and contractable within a range of a locus formed by a rouleau triangle.

  The excavator according to a third aspect of the present invention uses the rotating mechanism according to the first or second aspect, and arranges the annular member while disposing the blade member outside the tube and forming the other components inside. It is characterized by comprising a trunk portion provided so that its outer shape can be changed in accordance with the trajectory of the blade member at each rotational position of the shaft, and an excavation cutter in which a cutter is disposed on the blade member.

  According to the present invention, the rotation shaft rotates about the fixed center line by transmitting the driving force of the drive unit to the rotation shaft in the form in which the annular shaft is at the first rotation position. Then, the annular shaft that engages with the first outer peripheral portion of the rotating shaft rotates in the same direction as the rotating shaft around the movement center line in a form held by the holding member. Further, since the outer peripheral portion of the annular shaft that rotates about the moving center line is engaged with the inner peripheral portion of the bearing, it is opposite to the rotating shaft around the fixed center line along the inner peripheral portion of the bearing. It will rotate in the direction (revolution). For this reason, the blade member provided on the annular shaft rotates and revolves as the annular shaft rotates. The tip of the moving blade member has a substantially rectangular locus that is non-circular. And if it is set as the excavator provided with the excavation cutter which provided the cutter to the blade member, a substantially rectangular excavation hole can be excavated.

  On the other hand, by transmitting the driving force of the drive unit to the rotating shaft in the form in which the annular shaft is at the second rotating position, the rotating shaft rotates around the fixed center line. Then, the annular shaft engaged with the second outer peripheral portion of the rotating shaft rotates in the same direction as the rotating shaft about the fixed center line. Here, the annular shaft rotating around the fixed center line does not rotate (revolve) because its outer peripheral portion is separated from the inner peripheral portion of the bearing. For this reason, the blade member provided on the annular shaft rotates only around the fixed center line. The tip of the moving blade member has a circular trajectory. And if it is set as the excavator provided with the excavation cutter which provided the cutter on the blade member, a circular excavation hole can be excavated.

  In addition, when obtaining a circular trajectory or excavation hole, a circular trajectory (excavation hole) can be obtained within the range of a substantially rectangular trajectory (excavation hole) by reducing the length of the blade member. . Further, in the excavator, when excavating a substantially rectangular excavation hole, a trunk portion is provided along the shape of the excavation hole, and when excavating a circular excavation hole, the excavator along the shape of the excavation hole is provided. Is provided.

  Thus, according to the present invention, in the form in which the annular shaft is in the first rotation position, a non-circular substantially rectangular locus (excavation hole) can be obtained, while the annular shaft is rotated second. In the form of the position, a circular locus (excavation hole) can be obtained at the same center as the substantially rectangular shape. As a result, in the excavator, a series of continuous excavation holes can be obtained by combining substantially rectangular and circular excavation sections.

  Exemplary embodiments of a rotating mechanism and an excavator according to the present invention will be described below in detail with reference to the accompanying drawings. Note that the present invention is not limited to the embodiments.

  FIG. 1 is a schematic sectional side view showing a first rotation position of an excavator using a rotation mechanism according to the present invention, and FIG. 2 is a view of the rotation mechanism shown in FIG. 1 from the axial direction (forward direction). FIG. 3 is a schematic side sectional view showing a second rotational position of the excavator using the rotating mechanism according to the present invention, and FIG. 4 is a schematic view of the rotating mechanism shown in FIG. It is the conceptual diagram seen from (direction).

  As shown in FIGS. 1 and 2, the excavator includes a trunk portion 1 and an excavation cutter 2. The trunk portion 1 drives the excavation cutter 2 while supporting the excavation cutter 2. The trunk portion 1 forms an outline of the excavator and includes a rotating mechanism 3 in a cylindrical shape. The rotation mechanism 3 in the present embodiment forms a substantially rectangular (non-circular) locus shown by a two-dot chain line in FIG. 2 and a circular locus as shown in FIG. The excavator using the rotating mechanism 3 excavates substantially rectangular and circular excavation holes.

  The rotation mechanism 3 includes a bearing 31, an annular shaft 32, a rotation shaft 33, a holding member 34, a drive unit 35, and a rotation form changing unit 36.

  The bearing 31 is fixed to the body 1 and has a hole formed in a substantially circular shape around a predetermined fixed center line P arranged along the front-rear direction of the body 1. On the inner peripheral surface of the hole of the bearing 31, an inner peripheral portion 311 that forms an internal gear is provided along the circumference of the circle.

  The annular shaft 32 is formed in a substantially annular shape around a predetermined movement center line G arranged along the front-rear direction of the body portion 1 in parallel with the fixed center line P. On the inner peripheral surface of the annular shaft 32, an inner peripheral portion 321 that forms an internal gear is provided along the circumference of the circle. Further, the outer peripheral surface of the annular shaft 32 is provided with an outer peripheral portion 322 that forms an external gear along the circumference of the circle. The annular shaft 32 is arranged in the bearing 31 so that a part of the outer peripheral part 322 abuts and engages with a part of the inner peripheral part 311 of the bearing 31.

  Further, as shown in FIGS. 1 and 2, the annular shaft 32 has a first rotational position where a part of the outer peripheral part 322 is engaged with a part of the inner peripheral part 311 of the bearing 31, and FIGS. 3 and 4. As shown in FIG. 4, the outer peripheral portion 322 is provided so as to be movable to the second rotational position separated from the inner peripheral portion 311 of the bearing 31 with the moving center line G coinciding with the fixed center line P.

  The rotation shaft 33 is provided so as to be rotatable about a fixed center line P as a rotation center. The rotating shaft 33 has a first outer peripheral portion 331 and a second outer peripheral portion 332 that form an external gear along a circle around the fixed center line P. The first outer peripheral portion 331 is configured so as to be abutted and engaged with a part of the inner peripheral portion 321 of the annular shaft 32 by being housed inside the annular shaft 32. The second outer peripheral portion 332 is configured to be fitted in the annular shape of the annular shaft 32 so as to abut and engage along the entire circumference of the inner peripheral portion 321 of the annular shaft 32. The first outer peripheral portion 331 and the second outer peripheral portion 332 are arranged along the fixed center line P.

  Further, as shown in FIGS. 1 and 2, the rotation shaft 33 is engaged with the inner periphery 321 of the annular shaft 32 at the first rotation position, and the position where the first outer periphery 331 is engaged, as shown in FIGS. As shown in FIG. 5, the second outer peripheral portion 332 is engaged with the inner peripheral portion 321 of the annular shaft 32 at the second rotational position and is movable along the fixed center line P.

  The holding member 34 is formed in a disk shape centered on the fixed center line P, and has an outer peripheral surface having the same diameter as the inner peripheral surface of the bearing 31 around the fixed center line P. A convex portion 341 that is in sliding contact and a hole portion 342 that has an inner peripheral surface that is substantially the same diameter as the outer peripheral surface of the annular shaft 32 around the movement center line G and that is in sliding contact with the outer peripheral surface are provided. The holding member 34 has an annular support portion 344 attached to a disc-shaped outer peripheral edge 343. The support portion 344 and the outer peripheral edge 343 of the holding member 34 are provided to be relatively rotatable. The holding member 34 has a support portion 344 attached to the bearing 31 around the fixed center line P, and a part of the outer peripheral portion 322 of the annular shaft 32 is formed on the inner periphery of the bearing 31 as shown in FIGS. The outer peripheral surface of the annular shaft 32 is brought into sliding contact with the inner peripheral surface of the bearing 31 while being in contact with and engaged with a part of the portion 311 (first rotation position). The inner peripheral surface of the hole 342 is brought into sliding contact. That is, the holding member 34 is rotatable about the fixed center line P, and is rotatably inserted through the annular shaft 32 around the movement center line G so as to rotate with the inner peripheral portion 321 of the annular shaft 32. While maintaining engagement with the first outer peripheral portion 331 of the shaft 33, engagement between the outer peripheral portion 322 of the annular shaft 32 and the inner peripheral portion 311 of the bearing 31 is maintained.

  Further, as shown in FIGS. 3 and 4, the holding member 34 is configured so that the sliding contact between the outer peripheral surface of the convex portion 341 and the inner peripheral surface of the bearing 31 is separated when the annular shaft 32 is in the second rotation position. It is provided so as to be movable along the fixed center line P. The annular shaft 32 is provided with a recess 323 that prevents contact interference with the hole 342 of the holding member 34 when the holding member 34 moves as described above and moves to the second rotational position. .

  The drive unit 35 rotates the rotation shaft 33 around the fixed center line P, and includes a drive source provided in the body 1 such as a motor. The drive unit 35 supports the rotary shaft 33 so as to be movable along the fixed center line P while transmitting rotational force to the rotary shaft 33. Note that the drive unit 35 may have a speed reduction mechanism as appropriate between the drive source and the rotary shaft 33 although not shown in the figure.

  The rotation form changing means 36 is for changing the rotation form of the rotation mechanism 3 by moving the annular shaft 32, the rotation shaft 33, and the holding member 34, and includes the annular shaft moving unit 361, the rotating shaft moving unit 362, and the holding unit. A member moving part 363 is provided. The annular shaft moving part 361 is composed of a jack provided on the bearing 31 (or the body part 1) on the fixed side, and the annular shaft 32 is moved to a first rotational position (see FIG. 1) and a second rotational position (see FIG. 3). Move to. The rotary shaft moving part 362 is composed of a jack built in the rotary shaft 33, and moves the rotary shaft 33 (the first outer peripheral part 331 and the second outer peripheral part 332) in the front-rear direction along the fixed center line P. The first outer peripheral portion 331 of the rotary shaft 33 is engaged with the inner peripheral portion 321 of the annular shaft 32 in the rotational position (see FIG. 1), while rotating to the inner peripheral portion 321 of the annular shaft 32 in the second rotational position. The second outer peripheral portion 332 of the shaft 33 is engaged (see FIG. 3). The holding member moving part 363 is composed of a jack provided on the bearing 31 (or the trunk part 1) on the fixed side, and the holding member 34 is moved in the front-rear direction along the fixed center line P so that the annular shaft 32 is the first. When in the rotational position, the engagement of the annular shaft 32, the bearing 31 and the rotational shaft 33 is maintained (see FIG. 1), while the retained state is released when the annular shaft 32 is in the second rotational position (see FIG. 1). (See FIG. 3).

  The excavation cutter 2 includes a blade member 21 provided at the front end of an annular shaft 32 extending to the front side of the body portion 1. The blade member 21 is within a virtual roulau triangular shape (indicated by a one-dot chain line in FIG. 2) with the center (center of gravity) placed on the movement center line G, and at least the center (movement center line G) and apex (T ) Are arranged along an extension line (not necessarily a straight line). The excavation cutter 2 is configured by providing an excavation bit (not shown) in front of the blade member 21. As shown by the alternate long and short dash line in FIG. 2, the rouleau triangle has a shape in which an arc connecting the other vertices T with each vertex T of the regular triangle as the center, and the outer width (passing width) is constant. Is. In addition, the blade member 21 is formed so that it can be expanded and contracted within the range of the locus formed by the Rouleau triangle.

  The blade member 21 is fixed to the front end of the annular shaft 32 via the support shaft 22. The support shaft 22 is supported by a slide member 37 provided on the bearing 31 (or the body portion 1) on the fixed side. The slide member 37 supports the annular shaft 32 so that the support shaft 22 coincides with the movement center line G and the fixed center line P when the annular shaft 32 moves to the first rotation position and the second rotation position. Supports rotation of the support shaft 22 about the movement center line G when in the first rotation position and rotation of the support shaft 22 about the fixed center line P when the annular shaft 32 is in the second rotation position. .

  Here, the dimensions of the bearing 31, the annular shaft 32 and the blade member 21 are set at the center (fixed center line P) of the inner peripheral portion 311 of the bearing 31 and the first outer peripheral portion 331 of the rotating shaft 33 as shown in FIG. [R] is the distance (eccentric amount) from the center of the annular shaft 32 to the center of the annular shaft 32 (movement center line G), the diameter of the outer peripheral portion 322 of the annular shaft 32 is [6r], and the diameter of the inner peripheral portion 311 of the bearing 31 is [ 8r]. And the extension line L which connects the center (movement center line G) of the virtual roulau triangle which arrange | positions the blade | wing member 21 and the vertex T is set to [L = 0.5a + r]. Here, [a] is the outer width (square side length) of the rouleau triangle.

  The excavator having the above configuration excavates a substantially rectangular excavation hole H1 in the form shown in FIGS. 1 and 2 with the annular shaft 32 in the first rotation position. In this case, by transmitting the driving force of the driving unit 35 to the rotating shaft 33 in the rotating mechanism 3, the rotating shaft 33 rotates around the fixed center line P (for example, counterclockwise in FIG. 2). Then, the annular shaft 32 that engages with the first outer peripheral portion 331 of the rotating shaft 33 is held by the holding member 34 in the same direction as the rotating shaft 33 (for example, counterclockwise in FIG. 2) about the movement center line G. Direction). Further, the annular shaft 32 that rotates about the movement center line G has an outer peripheral portion 322 engaged with an inner peripheral portion 311 of the bearing 31, and therefore, the bearing 31 extends along the inner peripheral portion 311 of the bearing 31. A rotary motion (revolution) is performed around the fixed center line P in the direction opposite to the rotation shaft 33 (for example, the clockwise direction in FIG. 2). For this reason, the excavation cutter 2 (blade member 21) provided on the annular shaft 32 rotates and revolves as the annular shaft 32 rotates. The tip T of the excavating cutter 2 that moves moves in a substantially rectangular (substantially square) locus.

  Specifically, since the ratio of the diameter [6r] of the outer peripheral portion 322 of the annular shaft 32 and the diameter [8r] of the inner peripheral portion 311 of the bearing 31 is set to 3: 4, FIG. 2 and FIG. As shown in FIG. 8, when the annular shaft 32 makes one rotation around the movement center line G, the annular shaft 32 revolves around the fixed center line P by 1/3 rotation. Accordingly, as shown in the movement position of the tip T (A, B, C) of the excavation cutter 2 in FIG. 2 and FIG. 5 to FIG. 8, the excavation cutter 2 similarly revolves and rotates, and has an angle as shown in FIG. It forms a rectangular (square) trajectory of an arc. As a result, the excavator H1 (see FIG. 8) having a substantially rectangular (substantially square) excavation section can be excavated by propelling the excavator forward (see FIG. 1).

  On the other hand, the excavator having the above configuration excavates the circular excavation hole H2 in the form shown in FIGS. 3 and 4 in which the annular shaft 32 is set at the second rotational position. In this case, by transmitting the driving force of the driving unit 35 to the rotating shaft 33 in the rotating mechanism 3, the rotating shaft 33 rotates around the fixed center line P (for example, counterclockwise in FIG. 4). Then, the annular shaft 32 engaged with the second outer peripheral portion 332 of the rotating shaft 33 rotates in the same direction as the rotating shaft 33 (for example, counterclockwise in FIG. 4) about the fixed center line P. Here, the annular shaft 32 rotating around the fixed center line P does not rotate (revolve) because the outer peripheral portion 322 is not engaged with the inner peripheral portion 311 of the bearing 31. For this reason, the excavation cutter 2 (blade member 21) provided on the annular shaft 32 rotates around the fixed center line P. The tip T of the excavating cutter 2 that moves is a circular locus. As a result, it becomes possible to dig a circular excavation hole H2 (see FIG. 4) by propelling the excavator forward (see FIG. 3). In addition, when obtaining the circular locus | trajectory and the excavation hole H2, the circular locus | trajectory (in the range of the substantially rectangular locus | trajectory (excavation hole H1) is shortened by shortening the length of the blade member 21 (excavation cutter 2). It is possible to form a drilling hole H2). Further, in the excavator, the body portion 1 is provided along the shape of the excavation hole H1 when excavating the substantially rectangular excavation hole H1, and the shape of the excavation hole H2 is provided when excavating the circular excavation hole H2. The trunk | drum 1 along is provided.

  Thus, the rotation mechanism 3 in the above-described embodiment can form a substantially rectangular locus that is non-circular when the annular shaft 32 is in the first rotation position. On the other hand, in the form in which the annular shaft 32 is set to the second rotational position, a circular locus can be formed at the same center as the substantially rectangular shape. In the excavator using this rotating mechanism 3, the excavator H1 having a substantially rectangular shape (substantially square shape) that is non-circular and the circular excavation hole H2 is excavated at the same center by one excavator. It becomes possible to do. As a result, a series of continuous excavation holes can be obtained by combining substantially rectangular and circular excavation sections. In this case, for example, a subway line can be constructed by the circular excavation hole H2, and a subway station part and a vehicle branching part can be constructed by the substantially rectangular excavation hole H1. Further, by combining the rotation mechanism 3 and the conventional rotation mechanism for circular excavation, it is possible to obtain an excavation hole having an oblong excavation cross section by combining a substantially rectangular shape and a circular shape.

  Further, the rotation mechanism 3 in the above-described embodiment can change the noncircular shape by changing the amount of eccentricity [r] which is the distance between the fixed center line P and the movement center line G. Here, the eccentricity [r] will be described.

  As described above, when the rotating shaft 33 rotates, the annular shaft 32 that engages with the first outer peripheral portion 331 of the rotating shaft 33 revolves, and the moving center line G that is the center moves on a predetermined track. In order to obtain a substantially rectangular locus, the center (fixed center line P) of the rotation shaft 33 with respect to the movement center line G, which is the center (center of gravity) of the rouleau triangle, on the virtual rouleau triangle forming the blade member 21. It is geometrically known that the movement locus is almost circular and its radius [r] is about 7.7% to 8.2% of the outer width [a] of the virtual roulau triangle.

  In other words, as shown in FIG. 9, in the coordinate system in which the horizontal side of the square with the outer width [a] of the Ruroe triangle is the X coordinate and the vertical side is the Y coordinate, the Ruroux triangle is rotated in a form inscribed in the square. The locus of the center position of the square (the center of the rotation axis 33 (fixed center line P)) on the Rouleau triangle is observed. In FIG. 9, the locus indicated by a broken line is obtained by making the distance (the amount of eccentricity) [r] between the center (fixed center line P) of the rotation shaft 33 and the movement center line G constant at 0.0774a expressed by the following equation (1). is there.

  However, there are three trajectories indicated by broken lines in FIG. 9 with respect to the locus (indicated by a solid line in FIG. 9) of the center position of the square (the center of the rotation axis 33 (fixed center line P)) on the actual Rouleau triangle. Only matches. And in the case of the locus | trajectory shown with a broken line, each side of a substantially rectangular locus | trajectory will be formed in a slightly concave shape toward the inner side. The excavation hole excavated along this locus is not preferable because the strength is mechanically reduced.

  The locus shown by the solid line includes 0.0816a expressed by the following formula 2, and the distance (eccentric amount) between the center of the rotating shaft 33 (fixed center line P) and the center of the annular shaft 32 (moving center line G) [ r] is 0.0774a to 0.0816a. Therefore, if the eccentric amount [r] is 6% to 8% of the outer width [a] of the virtual ruler triangle, the cross-sectional shape of the excavated hole H1 is an ideal substantially rectangular shape having sufficient strength. .

  The rotary mechanism 3 of the excavator moves in a form in which the rotary shaft 33 is driven to rotate about the fixed center line P and the annular shaft 32 is held by the holding member 34 as the rotary shaft 33 rotates. Revolving around the fixed center line P while rotating around the center line G. As a result, the rotating shaft 33 rotates on the fixed center line P without shifting its axis, so that it is possible to reduce rotational shake and vibration. Further, since the annular shaft 32 revolves around the fixed center line P while rotating around the moving center line G in the form of being held by the holding member 34 as the rotating shaft 33 rotates, the rotation of the annular shaft 32 and Since the conventional universal joint is not required for the revolving movement, the cost related to the universal joint can be reduced.

  Further, the rotation mechanism 3 of the excavator is configured to revolve and rotate in a form in which the annular shaft 32 provided with the excavation cutter 2 (blade member 21) is held by the holding member 34. For this reason, it is not necessary to support and rotate the axis of the Rouleau triangle in a square frame having one side of the outer width of the Rouleau triangle so as to form a conventional approximately square locus. That is, a frame is not necessary. For this reason, it becomes possible to form the outline of the body part 1 of an excavator small in front view with respect to the cross-sectional shape of the excavated drill hole H1. As a result, since the trunk portion 1 can pass through the excavation hole H1 that the excavation cutter 2 has excavated in advance, it is possible to obtain an excavator that excavates the excavation hole H1 having an oval cross section. Further, the rotating mechanism 3 of the excavator obtains a non-circular locus with a configuration in which the annular shaft 32 provided with the excavating cutter 2 (blade member 21) is revolved and rotated in the form of being held by the holding member 34. For this reason, it is possible to reduce the manufacturing cost without using a complicated configuration using a swing arm as before. That is, the rotation mechanism 3 of the excavator obtains a non-circular rectangular trajectory and a circular trajectory by a simple mechanism, and forms a substantially rectangular cross-section excavation hole H1 and a circle with a non-circular cross-section. Since the excavation hole H2 having the shape cross section is dug, failure is unlikely to occur, the reliability is high, and the cost can be reduced.

It is an embodiment of an excavator using the rotating mechanism according to the present invention, and is a schematic side sectional view showing a first rotation position. It is the conceptual diagram which looked at the rotation mechanism shown in FIG. 1 from the axial direction (front direction). It is embodiment of the excavator using the rotation mechanism which concerns on this invention, Comprising: It is a schematic sectional side view which shows a 2nd rotation position. It is the conceptual diagram which looked at the rotation mechanism shown in FIG. 3 from the axial direction (front direction). It is a conceptual diagram which shows operation | movement of the rotation mechanism shown in FIG. It is a conceptual diagram which shows operation | movement of the rotation mechanism shown in FIG. It is a conceptual diagram which shows operation | movement of the rotation mechanism shown in FIG. It is a conceptual diagram explaining the rotation mechanism shown in FIG. It is a figure which shows the locus | trajectory of the center position of the square on a virtual roulau triangle.

Explanation of symbols

DESCRIPTION OF SYMBOLS 1 Body part 2 Excavation cutter 21 Blade member 22 Support shaft 3 Rotating mechanism 31 Bearing 311 Inner peripheral part 32 Annular shaft 321 Inner peripheral part 322 Outer peripheral part 323 Recessed part 33 Rotating shaft 331 First outer peripheral part 332 Second outer peripheral part 34 Holding member 341 Convex part 342 Hole part 343 Outer peripheral edge 344 Support part 35 Drive part 36 Rotation form changing means 361 Annular shaft moving part 362 Rotating shaft moving part 363 Holding member moving part 37 Slide member a Outer width of rouleau triangle r Eccentric amount G Moving center line H1, H2 Drilling holes L Extension line connecting the center and vertex of the rouleau triangle P Fixed centerline T Tip of the blade member (the apex of the rouleau triangle)

Claims (3)

A fixed bearing having an annular inner periphery centered on a predetermined fixed center line;
An inner periphery and an outer periphery centering on a predetermined movement center line parallel to the fixed center line are arranged inside the bearing, and the outer periphery is associated with the inner periphery of the bearing. An annular shaft provided so as to be movable to a second rotation position where the outer peripheral portion is separated from the inner peripheral portion of the bearing with the first rotation position and the fixed center line aligned with the movement center line
A first outer peripheral portion that is rotatably provided with the fixed center line as a center of rotation, and abuts and engages with a part of the inner peripheral portion of the annular shaft at the first rotational position, and the annular shaft at the second rotational position. A second outer peripheral portion that abuts and engages along the entire circumference of the inner peripheral portion of the rotating shaft disposed along the fixed centerline;
A drive unit that rotationally drives the rotary shaft;
When the annular shaft is in the first rotational position, the engagement between the inner peripheral portion of the annular shaft and the first outer peripheral portion of the rotary shaft is maintained between the outer peripheral portion of the annular shaft and the inner peripheral portion of the bearing. A holding member that holds the engagement;
The holding form of the holding member is maintained or released, the annular shaft is moved to the first rotational position or the second rotational position, and the rotational shaft is moved along the fixed center line in accordance with each rotational position of the annular shaft. A rotating form changing means for moving;
A rotating mechanism comprising: a vane member provided on the annular shaft and disposed along an extension line connecting at least the center and the apex of a Rouleau triangle centered on the moving center line.   The rotating mechanism according to claim 1, wherein the blade member is formed to be extendable and contractable within a range of a locus formed by a Rouleau triangle. Using the rotation mechanism according to claim 1 or 2,
A barrel portion that is arranged so that the outer shape can be changed in accordance with the trajectory of the blade member at each rotational position of the annular shaft while the blade member is arranged outside the tube and the other components are arranged inside.
An excavator comprising: an excavation cutter in which a cutter is disposed on the blade member.

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