Patent Publication Number: US-10322488-B2

Title: Rotating tool, and polishing tool

Description:
FIELD 
     The present invention relates to a rotating tool configured to process the inner circumferential surface of a hole formed in a workpiece, and relates to a polishing tool included in the rotating tool. Furthermore, the present invention relates to a processing method of processing the inner circumferential surface of a hole formed in a workpiece with the rotating tool. 
     BACKGROUND 
     When a tool is inserted into a hole formed in a workpiece to polish the inner circumferential surface of the hole or to deburr the edge of another hole intersecting with the above-mentioned hole, a rotating tool including grinding members at the front end thereof is employed. Patent Literature 1 describes a rotating tool including a plurality of linear grinding members, a grinding member holder to bundle the rear ends of the plurality of linear grinding members, and a shank extending backward coaxially from the grinding member holder. 
     CITATION LIST 
     Patent Literature 
     Patent Literature 1: Japanese Unexamined Patent Application Publication No. 2007-75954 (JP 2007-75954 A) 
     SUMMARY 
     Technical Problem 
     When the bottom of a hole formed in a workpiece is polished, a rotating tool needs to include a shank having a length corresponding to the depth of the hole so as to bring the front ends of grinding members into contact with the bottom of the hole. However, in the case where the shank has a longer length, when the rotating tool attached to a machine tool is rotationally driven, large run-outs can easily occur on the front side of the rotating tool due to centrifugal force. Here, when a run-out occurs in the rotating tool, the position of the polishing tool including a grinding member and a grinding member holder becomes unstable, and accordingly, the accuracy of processing is lowered. Furthermore, there is a possibility that the run-out polishing tool comes into contact with a workpiece, thereby damaging the workpiece. Furthermore, there is a possibility that the run-out causes the shank to be badly bent or broken. 
     In view of these problems, an object of the present invention is to provide a rotating tool capable of controlling the run-out caused by centrifugal force when the inner circumferential surface of a hole formed in a workpiece is processed. Furthermore, an object of the present invention is to provide a polishing tool included in the rotating tool. Furthermore, an object of the present invention is to provide a processing method of processing the inner circumferential surface of a hole formed in a workpiece while controlling the run-out of the rotating tool. 
     Solution to Problem 
     To solve the problems, the present invention relates to a rotating tool configured to be inserted into a hole having a certain depth formed in a workpiece so as to process an inner circumferential surface of the hole, the rotating tool including: a tool body; and a spacer to maintain a certain spacing between a rotation center axial line of the tool body and a peripheral wall surface of the hole, in which the tool body includes a grinding member, a grinding member holder to hold a rear end of the grinding member, and a shank extending backward coaxially from the grinding member holder. 
     According to the present invention, when the inner circumferential surface of a hole formed in a workpiece is processed, a certain spacing between the rotation center axial line of the rotating tool and the peripheral wall surface of the hole is maintained by the spacer. With this configuration, the run-out range of the tool body is regulated, whereby a decrease in the accuracy of processing is reduced. Furthermore, since the run-out of the tool body is reduced, a workpiece can be prevented from being damaged by a contact of the workpiece with the grinding member holder or the shank. Furthermore, the shank can be prevented from being bent or broken due to the run-out. 
     In the present invention, the spacer may be integrally formed with the tool body, or may be detachably attached to the tool body. With this configuration, in the case where a run-out of the tool body occurs due to the rotation thereof, the spacer comes into contact with the peripheral wall surface of the hole, whereby the run-out range of the tool body can be regulated. 
     In the present invention, the spacer is preferably attached to the tool body in a state of being movable in a direction of the rotation center axial line. With this configuration, when the spacer comes into contact with the peripheral wall surface of the hole, the spacer moves independently of the tool body, and thus, the movement of the tool body in the forward and backward directions can be prevented from being inhibited. 
     In the present invention, the spacer is preferably attached to the tool body in a state of being rotatable about the rotation center axial line. With this configuration, when the spacer comes into contact with the peripheral wall surface of the hole, the spacer moves independently of the tool body, and thus, the rotation of the tool body can be prevented from being inhibited. 
     In the present invention, the spacer may include a fixed part to be fixed to the peripheral wall surface of the hole, and the tool body may penetrate the spacer in a freely rotatable state. That is, the spacer may not be attached to the tool body. In this case, for example, the spacer having a center hole is inserted into a hole of a workpiece and fixed to the peripheral wall surface of the hole. Thereafter, the tool body is made to penetrate the center hole of the spacer and rotate, whereby the inner circumferential surface of the hole can be processed. 
     In the present invention, the spacer may be shrinkable around the axial line in a radial direction. With this configuration, in the case where the inner circumferential surfaces of a plurality of holes having different inner diameters are continuously processed, the spacer is made to shrink in accordance with the diameters of the holes and inserted into the holes, whereby a certain spacing between the rotation center axial line of the tool body and the peripheral wall surfaces of the holes can be maintained. Accordingly, the frequency of change of the spacer in accordance with the inner diameters of the holes to be processed can be decreased. 
     In the present invention, the spacer may have an outer diameter that increases gradually continuously or step by step from the grinding member side toward the shank side along the axial line. With this configuration, in the case where the inner circumferential surfaces of a plurality of holes having different inner diameters are continuously processed, the spacer is inserted partially into the holes, whereby a certain spacing between the rotation center axial line of the tool body and the peripheral wall surface of the holes can be maintained. Accordingly, the frequency of change of the spacer in accordance with the inner diameters of the holes to be processed can be decreased. 
     In the present invention, the spacer preferably includes a plurality of spacers disposed so as to be spaced from each other in a direction of the rotation center axial line. With this configuration, for example, in the case where the inner circumferential surface of a deep hole is processed with a tool body having a long shank, the plurality of spacers can maintain a certain spacing between the rotation center axis of the tool body and the peripheral wall surface of the hole, thereby preventing the run-out of the tool body. 
     In the present invention, the tool body may include a through hole that penetrates in a direction of the rotation center axial line. With this configuration, even when the opening of a hole is blocked by the insertion of the spacer into the hole, machining oil and air can be supplied into the hole via the through hole, and a processed part can be cooled. 
     In the present invention, the grinding member holder may include: an annular holder body part holding the rear end of the grinding member; a bar-shaped part penetrating the holder body part and slidably supporting the holder body part in a direction of the rotation center axial line; and a fixing mechanism fixing the holder body part to the bar-shaped part, and the shank may extend backward from the bar-shaped part. With this configuration, the holder body part is slid in the direction of the rotation center axial line and fixed to the bar-shaped part, whereby the front end of the grinding member can be disposed at a desired position corresponding to the depth of a hole. Furthermore, also in the case where the grinding member is worn out by processing operation, the front end of the grinding member can be disposed at a desired position by sliding the holder body part forward. Furthermore, in the case where the grinding member is worn out, it is only required to pull out the holder body part from the bar-shaped part and replace the holder body part with a new one, and thus, the bar-shaped part can be reused. 
     In the present invention, the grinding member preferably includes a plurality of linear grinding members, and the grinding member holder preferably holds rear ends of the plurality of linear grinding members in a bundle. When the tool body is a brush-shaped grindstone including a plurality of linear grinding members, processing, such as polishing of the bottom of a hole, polishing of a corner between the bottom and the peripheral wall surface of a hole, and deburring of the edge of a hole intersecting with this hole, can be performed with high accuracy. 
     In the present invention, the grinding member holder and the grinding member preferably constitute a polishing tool, and the polishing tool preferably includes a connecting part configured to detachably connect the shank to the grinding member holder. With this configuration, a plurality of shanks having different lengths is prepared, and a shank corresponding to the depth of a hole is connected to the polishing tool, whereby the inner circumferential surfaces of a plurality of holes having different depths can be processed. Furthermore, in the case where the grinding member is worn out, the polishing tool can be replaced with a new one. 
     Next, the present invention provides a polishing tool included in the rotating tool. 
     The polishing tool of the present invention includes a connecting part to a shank, thereby being attachably and detachably connected to the shank, whereby the shank can be changed in accordance with the depth of a hole. 
     Furthermore, the present invention provides a processing method of processing the inner circumferential surface of a hole having a certain depth formed in a workpiece with a rotating tool including a grinding member, a grinding member holder holding rear ends of the grinding member, and a shank extending backward coaxially from the grinding member holder, the processing method including inserting a spacer into the hole, and rotating the tool body in a state that a certain spacing between the rotation center axial line of the tool body and the peripheral wall surface of the hole is maintained by the spacer. 
     According to the present invention, when the inner circumferential surface of a hole formed in a workpiece is processed, a certain spacing between the rotation center axial line of the tool body and the peripheral wall surface of the hole is maintained by the spacer. With this configuration, the run-out of the tool body is reduced, whereby a decrease in the accuracy of processing is reduced. Furthermore, since the run-out of the tool body is reduced, a workpiece can be prevented from being damaged by a contact of the workpiece with the grinding member holder or the shank. Furthermore, the shank can be prevented from being bent or broken due to the run-out. 
    
    
     
       BRIEF DESCRIPTION OF DRAWINGS 
         FIG. 1  is a perspective view and a cross-sectional view of a rotating tool of Embodiment 1. 
         FIG. 2  is an exploded perspective view of the rotating tool illustrated in  FIG. 1 . 
         FIG. 3  is an illustration of a processing method using the rotating tool illustrated in  FIG. 1 . 
         FIG. 4  is a perspective view and a cross-sectional view of a rotating tool of Embodiment 2. 
         FIG. 5  is a perspective view of a rotating tool of Embodiment 3 and a perspective view of an annular member. 
         FIG. 6  is an illustration of a processing method using the rotating tool illustrated in  FIG. 5 . 
         FIG. 7  is a perspective view of a rotating tool of Embodiment 4 and a perspective view of an annular member. 
         FIG. 8  is an illustration of a processing method using the rotating tool illustrated in  FIG. 7 . 
         FIG. 9  is a perspective view and a cross-sectional view of a rotating tool of Embodiment 5. 
         FIG. 10  is an illustration of a processing method using the rotating tool illustrated in  FIG. 9 . 
         FIG. 11  is a perspective view of a rotating tool of Embodiment 6. 
         FIG. 12  is a cross-sectional view of the rotating tool illustrated in  FIG. 11 . 
         FIG. 13  is an illustration of a processing method using the rotating tool illustrated in  FIG. 11 . 
         FIG. 14  is a perspective view and a cross-sectional view of a rotating tool of Embodiment 7. 
         FIG. 15  is an exploded perspective view of the rotating tool illustrated in  FIG. 14 . 
         FIG. 16  is a perspective view and a cross-sectional view of a rotating tool of Embodiment 8. 
         FIG. 17  is an exploded perspective view of the rotating tool illustrated in  FIG. 16 . 
     
    
    
     DESCRIPTION OF EMBODIMENTS 
     Rotating tools according to the present invention are described below with reference to the drawings. 
     Embodiment 1 
       FIG. 1( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 1( b )  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line of the rotating tool.  FIG. 2  is an exploded perspective view of the rotating tool illustrated in  FIG. 1 .  FIG. 3  is an illustration of a method of processing the inner circumferential surface of a hole with this rotating tool  1  of the present embodiment. The rotating tool  1  of the present embodiment is attached to a machine tool such as a machining center, or to a manual rotating machine tool to perform polishing of the inner circumferential surface of a hole formed in a workpiece and deburring of the edge of another hole intersecting with the above-mentioned hole. As illustrated in  FIG. 1( a ) , the rotating tool  1  includes a polishing tool  2  and a shank  3  which are coaxially connected to each other in the direction of an axial line L, and a flange part  4 . The polishing tool  2  and the shank  3  constitute a tool body  5 , and the flange part  4  is provided at some point in the tool body  5  in the direction of the axial line L (rotation center axial line). The flange part  4  is a part projecting toward the outer circumference side, and, in the present embodiment, the flange part  4  is composed of an annular member (spacer)  8 , which is a component separate from the tool body  5 . Hereinafter, the rotating tool  1  is described with the polishing tool  2  side as the front and the shank  3  side as the rear. 
     The polishing tool  2  includes a plurality of linear grinding members (grinding members)  6 , and a grinding member holder  7  holding the rear ends of the linear grinding members  6 . In the present embodiment, the flange part  4  is an annular member  8 , which is coaxially attached to the grinding member holder  7 . 
     The linear grinding members  6  each are such that an aggregate of inorganic filaments, such as aluminum filaments, is impregnated with a resin binder, such as an epoxy resin or a silicone resin, and cured to be shaped in a line. The linear grinding members  6  are held by the grinding member holder  7 , thereby being brush-shaped. Note that, as the linear grinding members held by the grinding member holder  7 , nylon, abrasive grain-containing nylon, abrasive grain-containing rubber, or a metal wire made of stainless steel, brass, or the like may be used. Furthermore, an annular grindstone may be used in place of the linear grinding members. Examples of the grindstone include a rubber grindstone containing abrasive grains. 
     The grinding member holder  7  is made of metal and has a cylindrical external shape. As illustrated in  FIG. 1( b ) , the grinding member holder  7  includes a grinding member holding part  11  on the front side thereof to hold the linear grinding members  6 . Furthermore, as illustrated in  FIG. 2 , the grinding member holder  7  includes a tool-side threaded part  12  at the rear end thereof. The tool-side threaded part  12  is a connecting part on the polishing tool  2  side to connect the shank  3  to the polishing tool  2 . The tool-side threaded part  12  has a cylindrical shape, and a male thread is formed in the outer circumferential surface of the tool-side threaded part  12 . A fitted part  13  to fit the annular member  8  therein is provided between the tool-side threaded part  12  and the grinding member holding part  11 . The outer diameter of the fitted part  13  is smaller than the outside dimension of the grinding member holding part  11 . The outer diameter of the tool-side threaded part  12  is smaller than the outer diameter of the fitted part  13 . Accordingly, a first stage (a first movement-regulation part)  14  including a first annular end surface facing backward is formed between the grinding member holding part  11  and the fitted part  13 . A second stage  15  including a second annular end surface facing backward is formed between the fitted part  13  and the tool-side threaded part  12 . Note that the grinding member holder  7  may also be made of resin. 
     As illustrated in  FIG. 1( b ) , a grinding member holding recess  16  having a circular shape and being recessed in the direction of the axial line L is formed at the center of the front end surface of the grinding member holder  7 , that is, the front end surface of the grinding member holding part  11 . The rear ends of the plurality of linear grinding members  6  are inserted in a bundle into the grinding member holding recess  16 , and fixed thereto by an adhesive. In the outer circumferential surface of the grinding member holding part  11 , a pair of cut-out portions  17  cut from the outer circumference side is formed on both sides across the axial line L. Each of the cut-out portions  17  in a pair has a cut-out surface parallel to the axial line L. The grinding member holder  7  includes a holder through hole  18  that penetrates the tool-side threaded part  12 , the fitted part  13 , and the grinding member holding part  11  in the direction of the axial line L. The front end opening of the holder through hole  18  is formed in the bottom of the grinding member holding recess  16 . The front end of the grinding member holding part  11  and a portion of the linear grinding members  6  that is adjacent to the grinding member holding part  11  are covered with a heat shrinkable tube  19 . 
     The annular member  8  is made of resin. The annular member  8  is held by the grinding member holder  7  in a state that the fitted part  13  is inserted in a center hole  8   a  of the annular member  8 . The inner diameter of the center hole  8   a  of the annular member  8  is larger than the outer diameter of the fitted part  13 , and smaller than the outer diameter of the grinding member holding part  11 . The length of the annular member  8  in the direction of the axial line L is shorter than the length of the fitted part  13  in the direction of the axial line L. Hence, the annular member  8  is rotatable relative to the grinding member holder  7  in a state of being fitted to the fitted part  13 . Furthermore, the annular member  8  is movable relative to the fitted part  13  in the direction of the axial line L in a state of being fitted to the fitted part  13 . The annular member  8  may also be made of rubber or metal. 
     In the outer circumferential edge of the front end surface of the annular member  8 , a first tapered surface  8   b  widening backward toward the outer circumference side is formed. In the outer circumferential edge of the rear end surface of the annular member  8 , a second tapered surface  8   c  widening forward toward the outer circumference side is formed. The annular member  8  has a shape having symmetry with respect to a virtual plane perpendicular to the axial line L at the center in the direction of the axial line L. 
     The shank  3  is made of metal and has a cylindrical external shape. The outer diameter of the shank  3  is equal to the outside dimension of the grinding member holding part  11  of the grinding member holder  7 . In the outer circumferential surface on the front side of the shank  3 , a pair of cut-out portions  21  cut from the outer circumference side is formed on both sides across the axial line L. Each of the cut-out portions  21  in a pair has a cut-out surface parallel to the axial line L. 
     At the center of the front end surface of the shank  3 , a circular connecting recess  22  recessed in the direction of the axial line L is formed as illustrated in  FIG. 1( b ) . In the inner circumferential surface of an annular wall  23  surrounding the connecting recess  22 , a female thread into which the tool-side threaded part  12  is screwed is formed. The connecting recess  22  is a connecting part on the shank  3  side to connect the shank  3  to the polishing tool  2 , and constitutes a connecting part  24  of the polishing tool  2  and the shank, together with the tool-side threaded part  12  of the polishing tool  2 . Furthermore, the shank  3  includes a shank through hole  25  penetrating in the direction of the axial line L. The front end opening of the shank through hole  25  is formed in the bottom of the connecting recess  22 . The shank  3  may also be made of carbon fiber reinforced plastics. 
     (Assembly of Rotating Tool) 
     In the assembly of the rotating tool  1 , the shank  3  having a length corresponding to the depth of a hole H to be processed (refer to  FIG. 3 ) that is provided in a workpiece W is prepared. Furthermore, the annular member  8  having an outer diameter corresponding to the inner diameter of the hole H to be processed is prepared. The outer diameter of the annular member  8  is preferably set such that the outer circumferential surface of the annular member  8  fits with the peripheral wall surface of the hole H, or the outer circumferential surface of the annular member  8  faces the peripheral wall surface with a small clearance therebetween. 
     Next, the rear end of the grinding member holder  7  is inserted into the center hole  8   a  of the annular member  8  so that the annular member  8  is held by the fitted part  13 . Subsequently, the tool-side threaded part  12  of the polishing tool  2  is screwed into the connecting recess  22  of the shank  3  so as to bring the front end surface of the annular wall  23  of the connecting recess  22  into contact with the second stage  15  between the fitted part  13  and the tool-side threaded part  12 . Here, the contact of the front end surface of the annular wall  23  of the connecting recess  22  with the second stage  15  can prevent axial displacement between the shank  3  and the grinding member holder  7  by loose fit tolerance. The screwing of the tool-side threaded part  12  into the connecting recess  22  is performed by engaging a tool such as a spanner in the cut-out portions  17  and the cut-out portions  21  formed in the grinding member holder  7  and the shank  3 , respectively. 
     The shank  3  is connected to the grinding member holder  7  to constitute the tool body  5 , so that the annular member  8  is attached to the grinding member holder  7  in a state that the movement of the annular member  8  in the direction of the axial line L is regulated in the range of the fitted part  13 . That is, when the annular member  8  moves forward, the annular member  8  comes into contact with the first stage  14  (the first movement-regulation part) between the fitted part  13  and the grinding member holding part  11 , whereby the forward movement of the annular member  8  is regulated. When the annular member  8  moves backward, the annular member  8  comes into contact with a front end surface  23   a  (a second movement-regulation part) of the annular wall  23  of the shank  3 , whereby the backward movement of the annular member  8  is regulated. Furthermore, when the shank  3  is connected to the grinding member holder  7 , the shank through hole  25  of the shank  3  communicates with the holder through hole  18  of the grinding member holder  7 . 
     (Processing Operation) 
     When the inner circumferential surface of the hole H formed in the workpiece W is polished, the shank  3  of the tool body  5  is connected to a rotating head of a machine tool via a tool holder  26  or the like, as illustrated in  FIG. 3 . Subsequently, the polishing tool  2  and the annular member  8  are inserted into the hole H. The insertion of the annular member  8  into the hole H can be performed using the first tapered surface  8   b  as a guide face. 
     Thereafter, the tool body  5  is rotationally driven to polish the inner circumferential surface of the hole H by the linear grinding members  6 . Here, in the case where the shank  3  is made longer for the purpose of polishing a portion near the bottom of the inner circumferential surface of the hole H, large run-outs can sometimes occur on the front side of the tool body  5  due to centrifugal force when the tool body  5  is driven. Such a run-out of the tool body  5  makes the position of the polishing tool  2  unstable, thereby causing a decrease in the accuracy of processing. Furthermore, when such a run-out occurs, there is a possibility that the grinding member holder  7  or the shank  3  may come into contact with the workpiece W, whereby the workpiece W may be damaged. Furthermore, the shank  3  is sometimes bent or broken due to the run-out. 
     To solve these problems, in the present embodiment, the annular member  8  is inserted into the hole H at the time of processing, whereby a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the annular member  8 , so that the run-out range of the tool body  5  is regulated. That is, in the case where the run-out on the front side of the tool body  5  occurs due to the rotation of the tool body  5 , the annular member  8  comes into contact with the peripheral wall surface of the hole H, thereby regulating the range of the run-out. As a result, the run-out of the polishing tool  2  is reduced, whereby the position of the polishing tool  2  is stabilized, and a decrease in the accuracy of processing can be prevented. Furthermore, the run-out of the tool body  5  is reduced, whereby the workpiece W can be prevented from being damaged by a contact of the grinding member holder  7  or the shank  3  with the workpiece W. Furthermore, the shank  3  can be prevented from being bent or broken due to the run-out. 
     In the present embodiment, the annular member  8  is attached to the grinding member holder  7  in a state of being movable in the direction of the axial line L and rotatable about the axial line L. With this configuration, when the annular member  8  comes into contact with the peripheral wall surface of the hole H, the annular member  8  moves independently of the grinding member holder  7 , and accordingly, the rotation of the polishing tool  2  can be prevented from being inhibited. That is, the annular member  8  plays the role of a sliding bearing to support the grinding member holder  7  in the hole H, thereby reducing the run-out of the tool body  5 . Furthermore, since the annular member  8  moves independently of the grinding member holder  7 , when the annular member  8  comes into contact with the peripheral wall surface of the hole H, the movement of the tool body  5  in the direction of the axial line L can be prevented from being inhibited. 
     Furthermore, in the present embodiment, the movement range of the annular member  8  in the direction of the axial line L is regulated, and therefore, although the annular member  8  is movable relative to the grinding member holder  7  in the direction of the axial line L, the annular member  8  can be prevented from moving toward the linear grinding member  6  side and interfering with the linear grinding members  6  during processing operation. Furthermore, the annular member  8  can be prevented from moving toward the shank  3  side and coming out of the hole H during processing operation. 
     In the present embodiment, the shank  3  is connected to the polishing tool  2  with the threads, and therefore can be easily attached thereto and detached therefrom. Hence, in the case where the linear grinding members  6  are worn out by repeating polishing, the polishing tool  2  can be easily replaced with a new one. 
     Furthermore, in the present embodiment, the shank through hole  25  of the shank  3  communicates with the holder through hole  18  of the grinding member holder  7 , and therefore, even when the opening of the hole H is blocked by the insertion of a member into the hole H during processing, machining oil and air can be supplied into the hole H via the shank through hole  25  and the holder through hole  18 . 
     Modification of Embodiment 1 
     In the above-mentioned embodiment, the connecting recess  22  having a female thread is formed on the shank  3  side, and the tool-side threaded part  12  into which a female thread is screwed is formed on the grinding member holder  7  side. However, a connecting recess having a female thread may be formed on the grinding member holder  7  side, and a threaded part to be screwed into a female thread may be formed on the shank  3  side. 
     Furthermore, in the case where a connecting recess having a female thread is formed on the grinding member holder  7  side and a threaded part to be screwed into a female thread is formed on the shank  3  side, a configuration may be adopted in which a fitted part having a small diameter is provided on the shank  3  side and the annular member  8  is held on the shank  3  side. 
     Embodiment 2 
       FIG. 4( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 4( b )  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line of the rotating tool. The rotating tool  1 A of the present embodiment differs from the rotating tool  1  of Embodiment 1 in the configuration of the connecting part  24  to connect the shank  3  to the grinding member holder  7 . Furthermore, the rotating tool  1 A of the present embodiment differs from the rotating tool  1  of Embodiment 1 in that the rotating tool  1 A is not provided with the cut-out portions  17  and the cut-out portions  21 , and is not provided with the shank through hole  25  and the holder through hole  18 . Note that the rotating tool  1 A of the present embodiment has the same configuration, other than the above, as that of the rotating tool  1 . Therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     The grinding member holder  7  includes a small-diameter cylindrical part (insertion part)  31  having an outside dimension smaller than that of the fitted part  13  on the rear side of the fitted part  13 , as illustrated in  FIG. 4( b ) . The small-diameter part  31  is a connecting part on the polishing tool  2  side to connect the shank  3  to the polishing tool  2 . At the center of the front end surface of the shank  3 , the circular connecting recess  22  recessed in the direction of the axial line L is formed. The connecting recess  22  is a connecting part on the shank  3  side to connect the shank  3  to the polishing tool  2 , and has a shape fittable with the small-diameter tubular part. In the annular wall  23  surrounding the connecting recess  22 , two threaded holes  32  that penetrate the annular wall  23  in a direction perpendicular to the axial line L are formed. The two threaded holes  32  are provided to be spaced at an angle of 90° about the axial line L. A connecting screw  33  is screwed into each of the threaded holes  32  from the outer circumference side. Note that the spacing angle between the two threaded holes  32  is not limited to 90°, and the threaded holes may be spaced at an angle of 120°. However, a spacing angle of 180° easily causes looseness, and therefore, a spacing angle of 180° is preferably avoided. 
     In the assembly of the rotating tool  1 A, the small-diameter part  31  of the polishing tool  2  is inserted into the connecting recess  22  of the shank  3 . Next, each of the connecting screws  33  is screwed into the corresponding one of the threaded holes  32  from the outside of the annular wall  23 . Then, the tip ends of the connecting screws  33  come into contact with the small-diameter part  31 , whereby the grinding member holder  7  and the shank  3  are fixed. 
     According to the present embodiment, the same operational effects as those of the rotating tool  1  of Embodiment 1 can be achieved. Furthermore, according to the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  to the shank  3  can be made simpler, whereby the cost of manufacturing the polishing tool  2 , which is a consumable, can be reduced. 
     In the case where the grinding member holder  7  is connected to the shank  3  by the threaded hole  32  provided in one of the shank  3  and the grinding member holder  7  and a threaded part provided in the other, the connection between the shank  3  and the grinding member holder  7  is sometimes loosened by the rotational driving of the tool body  5 . However, when the grinding member holder  7  is connected to the shank  3  by the connecting screws  33 , such looseness can be avoided. 
     Modification of Embodiment 2 
     As is the case with the rotating tool  1 , the rotating tool  1 A of the present embodiment may have a configuration in which the grinding member holder  7  has the holder through hole  18 ; the shank  3  has the shank through hole  25 ; and, when the grinding member holder  7  is connected to the shank  3 , the holder through hole  18  is connected to the shank through hole  25 . 
     Furthermore, in the embodiment above, the grinding member holder  7  includes the small-diameter part (insertion part)  31 , and the front end surface of the shank  3  is provided with the connecting recess  22 . However, a configuration may be adopted in which the rear end surface of the grinding member holder  7  is provided with a connecting recess having a threaded hole; the front side of the shank  3  is provided with a small-diameter part (insertion part), and the grinding member holder  7  is connected to the shank  3  by a screw screwed into the threaded hole. 
     Embodiment 3 
       FIG. 5( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 5( b )  is a perspective view of an annular member. A rotating tool  1 B of the present embodiment differs from the rotating tool  1  of Embodiment 1 in the shape of an annular member  41  included in the flange part  4 . Note that the rotating tool  1 B of the present embodiment has the same configuration, except the annular member  41 , as that of the rotating tool  1  of Embodiment 1. Therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     The annular member  41  includes: an annular part  42  in which the fitted part  13  is inserted into the center hole  8   a ; and a plurality of plate-shaped extension parts  43  extending radially backward from the annular part  42  to the outer circumference side. In the outer circumferential edge of the annular front end surface of the annular part  42 , a tapered surface  42   a  inclined backward to the outer circumference side is provided. In the present embodiment, four sheets of the extension part  43  are provided. Each of the extension parts  43  has a tapered surface on the outer circumference side. Thus, the outer diameter of the annular member  41  gradually continuously increases backward. Furthermore, the rear end of each of the extension parts  43  is positioned at the rear of the rear end of the annular part  42 . Here, the annular member  41  is an integrally molded product made of resin, and the extension part  43  can bend, with the spring property, to the inner circumference side toward the annular part  42 . That is, the annular member  41  is shrinkable in the radial direction about the axial line L. 
     The annular member  41  is held by the grinding member holder  7  in a state of being rotatable about the axial line L and in a state that the movement of the annular member  41  in the forward and backward directions along the axial line L is regulated. That is, contact among the annular part  42 , the fitted part  13 , and the first stage  14  regulates the forward movement of the annular member  41 , and contact between the annular part  42  and the front end surface  23   a  of the annular wall  23  of the shank  3  regulates the backward movement of the annular member  41 . 
     (Processing Method) 
       FIG. 6  is an illustration of a processing method using the rotating tool  1 B of the present embodiment. In the present embodiment, when the annular member  41  is inserted into the hole H to be processed, the extension parts  43  are brought into contact with the peripheral wall surface of the hole H, and the extension parts  43  are bent to the inner circumference side in accordance with the inner diameter of the hole H and inserted into the hole H. Thus, while the position of the polishing tool  2  is stabilized by the annular member  41 , the polishing tool  2  can be guided into the hole H. In the present embodiment, the extension parts  43  of the annular member  41  are in contact with the peripheral wall surface of the hole H. When the annular member  41  comes into contact with the peripheral wall surface of the hole H, a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the annular member  41 . 
     Thereafter, the tool body  5  is rotationally driven to polish the inner circumferential surface of the hole H with the linear grinding members  6 . Here, the annular member  41  plays the role of a sliding bearing to support the grinding member holder  7  in the hole H. Accordingly, the run-out of the tool body  5  is reduced. 
     Furthermore, in the present embodiment, the extension parts  43  bend to the inner circumference side in accordance with the inner diameter of the hole H, and therefore, in the case where the inner circumferential surfaces of a plurality of holes H having different inner diameters are continuously processed, the frequency of change of the annular member  41  in accordance with the inner diameters of the holes H can be decreased. 
     Note that, in the rotating tool  1 B of the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  and the shank  3  may be a configuration using the connecting screws  33  as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. 
     Embodiment 4 
       FIG. 7( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 7( b )  is a perspective view of an annular member. A rotating tool  1 C of the present embodiment differs from the rotating tool  1  of Embodiment 1 in the shape of an annular member  51  included in the flange part  4 . Note that the rotating tool  1 C of the present embodiment has the same configuration, except the annular member  51 , as that of the rotating tool  1  of Embodiment 1. Therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     The annular member  51  includes: a first annular part  52  in which the fitted part  13  is inserted into a center hole  52   a ; a second annular part  53  which is disposed so as to be spaced backward from the first annular part  52  in the direction of the axial line L and into whose center hole  53   a  the shank  3  is inserted; and a plurality of linear connecting parts  54  configured to connect the first annular part  52  to the second annular part  53 . The first annular part  52  and the second annular part  53  are coaxially disposed, and the inner diameter of the second annular part  53  is larger than the inner diameter of the first annular part  52 . 
     The plurality of linear connecting parts  54  are annularly disposed so as to surround the axial line L. Each of the linear connecting parts  54  includes: a front side portion  54   a  extending backward from the first annular part  52  to the outer circumference side; and a rear side portion  54   b  extending backward from the rear end of the front side portion  54   a  to the inner circumference side to be continuous to the second annular part  53 . Here, the annular member  51  is an integrally molded product made of resin, and each of the linear connecting parts  54  can bend to the inner circumference side with spring property. That is, the annular member  51  is shrinkable in the radial direction about the axial line L taken as a center. Note that the annular member  51  may also be made of metal. 
     The first annular part  52  is fitted to the fitted part  13  in a state that the movement of the first annular part  52  in the forward and backward directions along the axial line L is regulated. That is, the contact of the first annular part  52  with the first stage  14  between the fitted part  13  and the grinding member holding part  11  regulates the forward movement of the annular member  51 , and the contact of the first annular part  52  with the front end surface  23   a  of the annular wall  23  of the shank  3  regulates the backward movement of the annular member  51 . 
     Here, the second annular part  53  has an inner diameter larger than the outside diameter of the shank  3 . Therefore, the second annular part  53  is held by the shank  3  in a state that the second annular part  53  and the first annular part  52  are rotatable about the axial line L in an integrated manner. Furthermore, the second annular part  53  is movable relative to the shank  3  in the direction of the axial line L, and is capable of changing a distance from the first annular part  52  within a range that the linear connecting parts  54  bend. 
     (Processing Method) 
       FIG. 8  is an illustration of a processing method using the rotating tool  1 C of the present embodiment. In the present embodiment, the annular member  51  is inserted into the hole H with each of the linear connecting parts  54  being brought into contact with the peripheral wall surface of the hole H and each of the linear connecting parts  54  being bent to the inner circumference side in accordance with the inner diameter of the hole H. The insertion of the annular member  51  into the hole H can be performed using the front side portions  54   a  of the annular member  51  as a guide face. Thus, the polishing tool  2  is inserted into the hole H in a state that the position of the polishing tool  2  is stable. Furthermore, in the present embodiment, the linear connecting parts  54  serve as a fixed part of the annular member  51  to the peripheral wall surface of the hole H. That is, when the linear connecting parts  54  come into contact with the peripheral wall surface of the hole H, reaction force acting on the linear connecting parts  54  allows the annular member  51  to be fixed to the hole H. When the annular member  51  is fixed to the hole H, a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the annular member  51 . 
     Thereafter, the tool body  5  is rotationally driven to polish the inner circumferential surface of the hole H by the linear grinding member  6 . Here, the annular member  51  plays the role of a sliding bearing to support the grinding member holder  7  in the hole H, and reduces the run-out of the tool body  5 . Therefore, also in the present embodiment, the same operational effects as in Embodiment 1 can be achieved. 
     Furthermore, in the present embodiment, the linear connecting parts  54  bend to the inner circumference side in accordance with the inner diameter of the hole H, and therefore, in the case where the inner circumferential surfaces of a plurality of holes H having different inner diameters are continuously processed, the frequency of change of the annular member  51  in accordance with the inner diameters of the holes H can be decreased. Furthermore, in the present embodiment, each of the linear connecting parts  54  is linear and flexibly bends, thereby allowing the tool body  5  to be inclined in the hole H. Therefore, even when the hole H has a bottom-projecting shape, the bottom-projecting portion can be processed. 
     Note that, in the rotating tool  1 C of the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  and the shank  3  may be a configuration using the connecting screw  33 , as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. 
     Embodiment 5 
       FIG. 9( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 9( b )  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line L of the rotating tool. A rotating tool  1 D of the present embodiment differs from the rotating tool  1  of Embodiment 1 in the configuration of the flange part  4 . Note that the rotating tool  1 D of the present embodiment has the same configuration, except an annular member  61 , as that of the rotating tool  1  of Embodiment 1. Therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     As illustrated in  FIG. 9( a ) , the flange part  4  includes a first annular member  61  to a sixth annular member  66 , which are arranged in this order from the front to the rear. Any of the annular members  61  to  66  have an annular shape. In the outer circumferential edge of the annular front end surface of each of the annular members  61  to  66 , the corresponding one of tapered surfaces  61   a  to  66   a  inclined backward to the outer circumference side is formed. 
     The first annular member  61  is fitted to the fitted part  13  of the grinding member holder  7  in a state of being movable in the direction of the axial line L and rotatable about the axial line L. That is, as illustrated in  FIG. 9( b ) , the forward movement of the first annular member  61  from the first stage  14  between the fitted part  13  and the grinding member holding part  11  is regulated, and the backward movement of the first annular member  61  is regulated by the front end surface  23   a  of the annular wall  23  of the shank  3 . 
     The second annular member  62  has an outer diameter larger than that of the first annular member  61 , the third annular member  63  has an outer diameter larger than that of the second annular member  62 , and the fourth annular member  64  has an outer diameter larger than that of the third annular member  63 . Furthermore, the fifth annular member  65  has an outer diameter larger than that of the fourth annular member  64 , and the sixth annular member  66  has an outer diameter larger than that of the fifth annular member  65 . Hence, the outer diameter of the flange part  4  gradually increases backward along the axial line L. Any of the second annular member  62  to the sixth annular member  66  are held by the shank  3  in a state that any of the annular members  62  to  66  are movable in the direction of the axial line L and rotatable about the axial line L. Furthermore, the first annular member  61  regulates the forward movement of the second annular member  62  to the sixth annular member  66  in the direction of the axial line L. 
     (Processing Method) 
       FIG. 10  is an illustration of a processing method using the rotating tool  1 D of the present embodiment. As illustrated in  FIG. 10 , the present embodiment is such that, in the processing of the inner circumferential surface of the hole H, among the first annular member  61  to the sixth annular member  66 , the first annular member  61  to the fifth annular member  65 , each having an outer diameter smaller than the inner diameter of the hole H, are dropped into the hole H by self-weight. 
     Thereafter, the rotating tool  1 D is rotationally driven to polish the inner circumferential surface of the hole H by the linear grinding members  6 . Here, when some of the annular members  61  to  65  are dropped into the hole H, a certain spacing between the axial line L of the rotating tool  1 D and the peripheral wall surface of the hole H is maintained by the annular member  65  which has the largest diameter among the annular members  61  to  65  arranged in the hole H, whereby the run-out range of the rotating tool  1 D is regulated. That is, when the rotating tool  1 D is rotated, the annular member  65  comes into contact with the peripheral wall surface of the hole H, thereby preventing the run-out of the rotating tool  1 D. Therefore, also in the present embodiment, the same operational effects as in Embodiment 1 can be achieved. 
     Furthermore, in the present embodiment, in the case where the inner circumferential surfaces of a plurality of holes H having different inner diameters are continuously processed, the frequency of change of the annular members in accordance with the inner diameters of the holes H can be decreased. That is, in the present embodiment, one or a plurality of the annular members  61  to  66  are inserted into the hole H in accordance with the inner diameter of the hole H, whereby the run-out of the rotating tool  1 D can be reduced. 
     Note that the number of the annular members included in the flange part  4  is not limited to six. 
     Note that, in the rotating tool  1 D of the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  and the shank  3  may be a configuration using the connecting screw  33 , as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. 
     Embodiment 6 
       FIG. 11  is a perspective view of a rotating tool of the present embodiment.  FIG. 12  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line L of the rotating tool. Note that a rotating tool  1 E of the present embodiment has the same configuration as that of the rotating tool  1  of Embodiment 1, and therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     As illustrated in  FIG. 11 , the rotating tool  1 E of the present embodiment includes the polishing tool  2  and the shank  3  which are coaxially connected in the direction of the axial line L. In the present embodiment, the shank  3  includes a first shank  71 , and a second shank  72  coaxially connected to the first shank  71  on the rear side of the first shank  71 . Hence, the polishing tool  2 , the first shank  71 , and the second shank  72  constitute the tool body  5 . Furthermore, in the present embodiment, as the flange part  4 , a first annular member  73  provided in the tool body  5  and a second annular member  74  provided in the shank  3  are included. The second annular member  74  is provided in the rear end of the first shank  71 . 
     The polishing tool  2  includes the plurality of linear grinding members  6 , and the grinding member holder  7  holding the rear ends of the plurality of linear grinding members  6 . The polishing tool  2  of the present embodiment has the same configuration as that of the polishing tool  2  of Embodiment 1. The first annular member  73  provided in the polishing tool  2  is composed of a first annular member  75 , and attached to the fitted part  13  of the grinding member holder  7 . The first annular member  75  has the same configuration as that of the annular member  8  of Embodiment 1, and is fitted to the fitted part  13  of the grinding member holder  7  in a state of being movable in the direction of the axial line L and rotatable about the axial line L. As illustrated in  FIG. 12 , the grinding member holder  7  includes the tool-side threaded part  12  adjacent to the rear side of the fitted part  13 . Furthermore, the grinding member holder  7  includes the holder through hole  18  penetrating in the direction of the axial line L. 
     The first shank  71  is made of metal and has a cylindrical external shape. As illustrated in  FIG. 12 , the first shank  71  includes, from the front to the rear: a tube part  77  having an outer diameter equal to the outside dimension of the grinding member holding part  11  of the grinding member holder  7 ; a shank-side fitted part  78  having a diameter smaller than that of the tube part  77 ; and a shank-side threaded part  79  having a diameter smaller than that of the shank-side fitted part  78 . Here, a second annular member  80  included in the second annular member  74  is fitted to the shank-side fitted part  78 . The second annular member  80  is the same member as the first annular member  75 . The length of the second annular member  80  in the axial line L direction is shorter than the length of the shank-side fitted part  78  in the axial line L direction. A male thread is formed in the outer circumferential surface of the shank-side threaded part  79 . 
     In the outer circumferential surface on the front side of the tube part  77 , a pair of first cut-out portions  81  cut from the outer circumference side is provided on both sides across the axial line L. Each of the first cut-out portions  81  in a pair has a cut-out surface parallel to the axial line L. At the center of the front end surface of the tube part  77 , the circular connecting recess  22  recessed in the direction of the axial line L is formed. In the inner circumferential surface of the annular wall  23  surrounding the connecting recess  22 , a female thread into which the tool-side threaded part  12  is screwed is formed. 
     In the outer circumferential surface on the rear side of the tube part  77 , a pair of second cut-out portions  82  cut from the outer circumference side is provided on both sides across the axial line L. Each of the second cut-out portions  82  in a pair has a cut-out surface parallel to the axial line L. Between the shank-side fitted part  78  and the tube part  77 , a shank-side stage  83  having an annular end surface facing backward is formed. Furthermore, the first shank  71  includes a first shank through hole  84  penetrating the shank-side threaded part  79 , the shank-side fitted part  78 , and the tube part  77  in the direction of the axial line L. The front end opening of the first shank through hole  84  is formed in the bottom of the connecting recess  22 . Note that the first shank  71  may also be made of carbon fiber reinforced plastics. 
     The second shank  72  is made of metal and has a cylindrical external shape. The outer diameter of the second shank  72  is equal to the outside dimension of the tube part  77  of the first shank  71 . In the outer circumferential surface on the front side of the first shank  71 , a pair of cut-out portions  86  cut from the outer circumference side is provided on both sides across the axial line L. Each of the cut-out portions  86  in a pair has a cut-out surface parallel to the axial line L. 
     At the center of the front end surface of the second shank  72 , a second circular connecting recess  87  recessed in the direction of the axial line L is formed. In the inner circumferential surface of an annular wall  88  surrounding the second connecting recess  87 , a female thread into which the shank-side threaded part  79  is screwed is formed. Furthermore, the second shank  72  includes a second shank through hole  89  penetrating in the direction of the axial line L. The front end opening of the second shank through hole  89  is formed in the bottom of the second connecting recess  87 . Note that the second shank  72  may also be made of carbon fiber reinforced plastics. 
     (Assembly of Rotating Tool) 
     When the rotating tool  1 E of the present embodiment is assembled, the rear end of the grinding member holder  7  is inserted into a center hole  75   a  of the first annular member  75  so that the first annular member  75  is held by the fitted part  13 . Thereafter, the tool-side threaded part  12  of the polishing tool  2  is screwed into the connecting recess  22  of the first shank  71 . The screwing of the tool-side threaded part  12  into the connecting recess  22  is performed by engaging a tool such as a spanner in the cut-out portions  17  of the grinding member holder  7  and the first cut-out portions  81  of the first shank  71 . 
     The grinding member holder  7  is connected to the first shank  71 , so that the first annular member  75  is attached to the grinding member holder  7  in a state that the movement of the first annular member  75  in the forward and backward directions along the axial line L is regulated in the range of the fitted part  13 . That is, the first stage  14  between the fitted part  13  and the grinding member holding part  11  of the grinding member holder  7  regulates the forward movement of the first annular member  75 , and the front end surface  23   a  of the annular wall  23  of the first shank  71  regulates the backward movement of the first annular member  75 . Furthermore, when the first shank  71  is connected to the grinding member holder  7 , the first shank through hole  84  of the first shank  71  communicates with the holder through hole  18  of the grinding member holder  7 . 
     Next, the rear end of the first shank  71  is inserted into a center hole  80   a  of the second annular member  80 , so that the second annular member  80  is held by the shank-side fitted part  78 . Thereafter, the shank-side threaded part  79  of the first shank  71  is screwed into the second connecting recess  87  of the second shank  72 . The screwing of the shank-side threaded part  79  into the second connecting recess  87  is performed by engaging a tool such as a spanner in the second cut-out portions  82  of the first shank  71  and the cut-out portions  86  of the second shank  72 . 
     The first shank  71  is connected to the second shank  72 , so that the second annular member  80  is attached to the first shank  71  in a state that the movement of the second annular member  80  in the forward and backward directions along the axial line L is regulated in the range of the shank-side fitted part  78 . That is, the shank-side stage  83  between the shank-side fitted part  78  and the tube part  77  of the first shank  71  regulates the forward movement of the second annular member  80 , and the front end surface  88   a  of the annular wall  88  of the second shank  72  regulates the backward movement of the second annular member  80 . Furthermore, when the first shank  71  is connected to the second shank  72 , the first shank through hole  84  of the first shank  71  communicates with the second shank through hole  89  of the second shank  72 . With this configuration, the first shank through hole  84 , the second shank through hole  89 , and the holder through hole  18  communicate with each other. 
     (Processing Method) 
       FIG. 13  is an illustration of a method of processing the inner circumferential surface of the hole H using the rotating tool  1 E of the present embodiment. When the inner circumferential surface of the hole H formed in the workpiece W is polished using the rotating tool  1 E of the present embodiment, the polishing tool  2 , the first annular member  75 , the first shank  71 , and the second annular member  80  are inserted into the hole H as illustrated in  FIG. 12 . Thereafter, the rotating tool  1 E is rotationally driven to polish the inner circumferential surface of the hole H by the linear grinding members  6 . 
     Here, the first annular member  75  and the second annular member  80  are inserted into the hole H, so that a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the first annular member  75  and the second annular member  80 , whereby the run-out range of the tool body  5  is regulated. That is, in the case where the run-out on the front side of the tool body  5  occurs due to the rotation of the tool body  5 , the first annular member  75  and the second annular member  80  come into contact with the peripheral wall surface of the hole H, thereby regulating the range of the run-out. As a result, the run-out of the polishing tool  2  is reduced, whereby a decrease in the accuracy of processing can be reduced. Furthermore, since the run-out of the tool body  5  is reduced, the workpiece W can be prevented from being damaged by a contact of the grinding member holder  7  or the shank  3  with the workpiece W. Furthermore, the shank  3  can be prevented from being bent or broken due to the run-out. 
     In the present embodiment, the first annular member  75  and the second annular member  80  are attached to the grinding member holder  7  and the shank  3 , respectively, in a state of being movable in the direction of the axial line L and rotatable about the axial line L. Accordingly, when the first annular member  75  and the second annular member  80  come into contact with the peripheral wall surface of the hole H, the annular members  75  and  80  move independently of the grinding member holder  7  and the shank  3 , respectively, and thus, the rotation of the polishing tool  2  can be prevented from being inhibited. That is, the first annular member  75  plays the role of a sliding bearing to support the grinding member holder  7  in the hole H, and the second annular member  80  plays the role of a sliding bearing to support the shank  3  in the hole H, whereby the run-out of the tool body  5  is reduced. Furthermore, since the annular members  75  and  80  move independently of the grinding member holder  7 , when the annular members  75  and  80  come into contact with the peripheral wall surface of the hole H, the movement of the tool body  5  in the direction of the axial line L can be prevented from being inhibited. 
     Furthermore, in the present embodiment, the movement range of the annular members  75  and  80  in the direction of the axial line L is regulated, and therefore, although the annular members  75  and  80  are movable in the direction of the axial line L, the annular members  75  and  80  can be prevented from moving toward the linear grinding member  6  side and interfering with the linear grinding members  6  during processing operation. Furthermore, the annular members  75  and  80  can be prevented from moving toward the second shank  72  side and coming out of the hole H during processing operation. 
     In the present embodiment, the polishing tool  2  is connected to the first shank  71  with the threads, and the first shank  71  is connected to the second shank  72  with the threads, and therefore, the polishing tool  2 , the first shank  71 , and the second shank  72  can be easily detached from each other. Hence, in the case where the linear grinding members  6  are worn out by repeating polishing, the polishing tool  2  can be easily replaced with a new one. Furthermore, a plurality of first shanks  71  and second shanks  72  having different lengths can be easily used in combination to connect to each other in accordance with the depth of the hole H. 
     Furthermore, in the present embodiment, the second shank through hole  89  of the second shank  72 , the first shank through hole  84  of the first shank  71 , and the holder through hole  18  of the grinding member holder  7  communicate with each other, and therefore, even when the opening of the hole H is blocked by the insertion of the annular members  75  and  80  into the hole H during processing, machining oil and air can be supplied into the hole H via the second shank through hole  89 , the first shank through hole  84 , and the holder through hole  18 . 
     Modification of Embodiment 6 
     In the rotating tool  1 E of the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  and the first shank  71  may be a configuration using the connecting screw  33 , as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. Furthermore, the configuration of the connecting part  90  of the first shank  71  and the second shank  72  may be a configuration using the connecting screw  33 , as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. 
     In the present embodiment, the shank  3  includes two shanks  3 , namely, the first shank  71  and the second shank  72 , but, may include three or more shanks. In this case, an annular member is preferably provided as the flange part  4  in the rear end of the two shanks connected in the forward and backward directions. 
     In the embodiment above, the connecting recess  22  including a female thread is formed on the first shank  71  side, and the tool-side threaded part  12  to be screwed into the female thread is formed on the grinding member holder  7  side. However, a connecting recess including a female thread may be formed on the grinding member holder  7  side, and a threaded part to be screwed into a female thread may be formed on the first shank  71  side. In this case, a configuration may be adopted in which a fitted part having a small diameter is provided on the first shank  71  side, so that the first annular member  75  is held on the first shank  71  side. 
     In the embodiment above, the second connecting recess  87  including a female thread is formed on the second shank  72  side, and the shank-side threaded part  79  to be screwed into the female thread is formed on the first shank  71  side. However, a connecting recess including a female thread may be formed on the first shank  71  side, and a threaded part to be screwed into a female thread may be formed on the second shank  72  side. In this case, a configuration may be adopted in which a fitted part having a small diameter is provided on the second shank  72  side, so that the second annular member  80  is held on the second shank  72  side. 
     Furthermore, in the embodiment above, the second shank through hole  89  is provided in the second shank  72 , the first shank through hole  84  is provided in the first shank  71 , and the holder through hole  18  is provided in the grinding member holder  7 . However, if a decrease in the rigidity of the shank  3  is caused by the through holes  84  and  89 , the through holes  18 ,  84 , and  89  may be omitted. 
     Embodiment 7 
       FIG. 14( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 14( b )  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line L of the rotating tool.  FIG. 15  is an exploded perspective view of the rotating tool illustrated in  FIG. 14 . Note that a rotating tool  1 F of the present embodiment has the same configuration as that of the rotating tool  1  of Embodiment 1, and therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     As illustrated in  FIG. 14( a ) , the rotating tool  1 F of the present embodiment includes the polishing tool  2  and the shank  3  which are coaxially connected in the direction of the axial line L, and the flange part  4  provided over the grinding member holder  7  and the shank  3 . That is, the polishing tool  2  and the shank  3  constitute the tool body  5 , and the flange part  4  is provided at some point in the tool body  5  in the direction of the axial line L. The flange part  4  is an annular member  95  coaxially attached to the connecting part  24  of the polishing tool  2  and the shank  3 . In the rotating tool  1 F, a first O-ring  96  is attached to the front side of the annular member  95  and a second O-ring  97  is attached to the rear side of the annular member  95  so that the annular member  95  is sandwiched between the first O-ring  96  and the second O-ring  97  in the direction of the axial line L. 
     The polishing tool  2  includes the plurality of linear grinding members  6 , and the grinding member holder  7  holding the rear ends of the plurality of linear grinding members  6 . The grinding member holder  7  has a cylindrical shape, and as illustrated in  FIG. 14( b ) , includes: the grinding member holding part  11  holding the linear grinding members  6 ; and the tool-side threaded part  12  having a diameter smaller than that of the grinding member holding part  11 , in this order from the front to the rear. The rear ends of the plurality of linear grinding members  6  are inserted in a bundle into the grinding member holding recess  16  of the grinding member holding part  11 , and fixed by an adhesive. Between the grinding member holding part  11  and the tool-side threaded part  12 , a stage  98  having an annular end surface facing backward is formed. The grinding member holder  7  includes the holder through hole  18  penetrating in the direction of the axial line L. 
     The shank  3  is made of metal and has a cylindrical external shape. The outer diameter of the shank  3  is equal to the outside dimension of the grinding member holding part  11  of the grinding member holder  7 . At the center of the front end surface of the shank  3 , the circular connecting recess  22  recessed in the direction of the axial line L is formed. In the inner circumferential surface of the annular wall  23  surrounding the connecting recess  22 , a female thread into which the tool-side threaded part  12  is screwed is formed. Furthermore, the shank  3  includes the shank through hole  25  penetrating in the direction of the axial line L. The front end opening of the shank through hole  25  is formed in the bottom of the connecting recess  22 . The shank  3  may also be made of carbon fiber reinforced plastics. 
     Here, the annular member  95  has the same configuration as that of the annular member  8  of the rotating tool  1  of Embodiment 1, but, the inner diameter of a center hole  95   a  of the annular member  95  is larger than the inner diameter of the center hole  8   a  of the annular member  8  of Embodiment 1, and the shank  3  and the grinding member holding part  11  of the grinding member holder  7  can be inserted into the center hole  95   a . Thus, the annular member  95  is held by the connecting part  24  of the polishing tool  2  and the shank  3  in a state of being movable in the direction of the axial line L and rotatable about the axial line L. 
     (Assembly of Rotating Tool) 
     When the rotating tool  1 F of the present embodiment is assembled, the first O-ring  96  is inserted into the grinding member holder  7  of the polishing tool  2  from the rear. Thereafter, the rear end of the grinding member holder  7  is inserted into the center hole  95   a  of the annular member  95  so that the annular member  95  is partially held by the grinding member holding part  11  of the grinding member holder  7 . Meanwhile, the second O-ring  97  is inserted into the shank  3  from the front, and, in this state, the tool-side threaded part  12  of the polishing tool  2  is screwed into the connecting recess  22  of the shank  3 . The screwing of the threaded part into the connecting recess  22  is performed by engaging a tool such as a spanner in the cut-out portions  17  of the grinding member holder  7  and the cut-out portions  21  of the shank  3 . 
     The shank  3  is connected to the grinding member holder  7 , so that the annular member  95  is attached to the shank  3  and the grinding member holder  7  in a state that the movement of the annular member  95  in the forward and backward directions along the axial line L is regulated in the range between the first O-ring  96  and the second O-ring  97 . That is, when the annular member  95  moves forward, the annular member  95  comes into contact with the first O-ring  96 , whereby the forward movement of the annular member  95  is regulated, whereas when the annular member  95  moves backward, the annular member  95  comes into contact with the second O-ring  97 , whereby the backward movement of the annular member  95  is regulated. Furthermore, when the shank  3  is connected to the grinding member holder  7 , the shank through hole  25  of the shank  3  communicates with the holder through hole  18  of the grinding member holder  7 . 
     (Processing Method) 
     When the inner circumferential surface of a hole H formed in the workpiece W is polished using the rotating tool  1 F of the present embodiment, the polishing tool  2  and the annular member  95  are inserted into the hole H, as is the case illustrated in  FIG. 3 . Thereafter, the tool body  5  is rotationally driven to polish the bottom of the hole H by the linear grinding members  6 . 
     Also in the present embodiment, the annular member  95  is inserted into the hole H, so that a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the annular member  95 , whereby the range of the run-out of the tool body  5  is regulated. Therefore, also in the present embodiment, the same effects as in Embodiment 1 can be achieved. 
     Furthermore, in the present embodiment, a position to attach the first O-ring  96  and a position to attach the second O-ring  97  each can be moved in the direction of the axial line L. Accordingly, the position of the annular member  95  can be adjusted in accordance with the depth of the hole H. Furthermore, the movement range of the annular member  95  in the direction of the axial line L can be adjusted. 
     Note that both the first O-ring  96  and the second O-ring  97  are inserted into the grinding member holder  7  so that the annular member  95  is positioned between the first O-ring  96  and the second O-ring  97 , whereby the annular member  95  can be held by the grinding member holder  7 . Furthermore, both the first O-ring  96  and the second O-ring  97  are inserted into the shank  3  so that the annular member  95  is positioned between the first O-ring  96  and the second O-ring  97 , whereby the annular member  95  can be held also by the shank  3 . 
     Furthermore, in the rotating tool  1 F of the present embodiment, the configuration of the connecting part  24  of the polishing tool  2  and the shank  3  may be a configuration using the connecting screw  33 , as is the case with the connecting part  24  of the polishing tool  2  and the shank  3  in Embodiment 2. 
     Embodiment 8 
       FIG. 16( a )  is a perspective view of a rotating tool of the present embodiment, and  FIG. 16( b )  is a cross-sectional view of the rotating tool of the present embodiment, including the axial line L of the rotating tool.  FIG. 17  is an exploded perspective view of the rotating tool illustrated in  FIG. 16 . A rotating tool  1 G of the present embodiment differs from the rotating tool  1  of Embodiment 1 in the configuration of the front end surface of the shank  3  and the configuration of the grinding member holder  7 . Note that the rotating tool  1 G of the present embodiment has the same configuration as that of the rotating tool  1  of Embodiment 1, and therefore, common reference signs are given to common constituents, and descriptions thereof are omitted. 
     As illustrated in  FIG. 16( a ) , the rotating tool  1 G includes the polishing tool  2  and the shank  3  which are coaxially connected in the direction of the axial line L, and the flange part  4 . The polishing tool  2  and the shank  3  constitute the tool body  5 . The flange part  4  is provided at some point in the tool body  5  in the direction of the axial line L (rotation center axial line). The flange part  4  is the annular member  8  which is a component separate from the tool body  5 . 
     The polishing tool  2  includes a plurality of grinding member bundles  101  each formed of a circular bundle of the plurality of linear grinding members (grinding members)  6 . Furthermore, the polishing tool  2  includes the grinding member holder  7  holding the rear ends of the plurality of grinding member bundles  101 . As illustrated in  FIG. 16( b ) , the grinding member holder  7  includes: an annular holder body part  102  to hold the rear ends of the grinding member bundles  101 ; a bar-shaped part  103  penetrating the holder body part  102  and slidably supporting the holder body part  102  in the direction of the axial line L (rotation center axial line); and two set screws  104  to fix the holder body part  102  to the bar-shaped part  103 . The shank  3  is connected to the rear end of the bar-shaped part  103 , and the shank  3  coaxially extends together with the bar-shaped part  103 . 
     The holder body part  102  and the bar-shaped part  103  are made of metal or resin. In the front end surface of the holder body part  102 , a plurality of circular grinding member holding recesses  16  recessed in the direction of the axial line L is formed. The grinding member holding recesses  16  are annularly arranged at equiangular intervals. The rear end of each of the grinding member bundles  101  is inserted into the corresponding one of the grinding member holding recesses  16 , and fixed by an adhesive. With this configuration, the grinding member bundles  101  protrude forward from the holder body part  102  in a state of being annularly arranged. The holder body part  102  and the grinding member bundles  101  constitute a cup-shaped polishing brush  105 . 
     Furthermore, two threaded holes  106  are formed in the outer circumferential surface of the holder body part  102 . The two threaded holes  106  are provided on opposite sides of the axial line L. Each of the threaded holes  106  penetrates in the radial direction perpendicular to the axial line L to communicate with a center hole  102   a  of the holder body part  102 . 
     As illustrated in  FIG. 17 , the bar-shaped part  103  includes an insertion part  107  on the front side which is inserted into the center hole  102   a  of the holder body part  102  to coaxially support the holder body part  102 . Two flat surfaces  107   a  extending in the direction of the axial line L are formed in the outer circumferential surface of the insertion part  107 . The two flat surfaces  107   a  are provided on opposite sides of the axial line L. Each of the flat surfaces  107   a  extends in parallel to the axial line L. 
     Furthermore, the bar-shaped part  103  includes the tool-side threaded part  12  in the rear end. The tool-side threaded part  12  is a connecting part on the polishing tool  2  side to connect the polishing tool  2  to the shank  3 . The tool-side threaded part  12  has a cylindrical shape, and a male thread is formed in the outer circumferential surface of the tool-side threaded part  12 . 
     The fitted  13  is formed between the insertion part  107  and the tool-side threaded part  12 . The outer diameter of the fitted part  13  is smaller than the outside dimension of the insertion part  107 . The outer diameter of the tool-side threaded part  12  is smaller than the outer diameter of the fitted part  13 . Thus, the first stage (first movement-regulation part)  14  including the first annular end surface facing backward is formed between the insertion part  107  and the fitted part  13 , and the second stage  15  including the second annular end surface facing backward is formed between the fitted part  13  and the tool-side threaded part  12 . Furthermore, the bar-shaped part  103  includes the holder through hole  18  penetrating in the direction of the axial line L. 
     In the assembly of the polishing tool  2 , first, the insertion part  107  of the bar-shaped part  103  is inserted into the center hole  102   a  of the holder body part  102 . Next, the holder body part  102  is slid along the bar-shaped part  103  so as to be disposed at a desired position in the direction of the axial line L. Thereafter, the set screws  104  are screwed into the threaded holes  106  of the holder body part  102 , and as illustrated in  FIG. 16( b ) , the ends (tips) on the inner circumference side of the set screws  104  are brought into contact with the flat surface  107   a  of the bar-shaped part  103 . With this configuration, the holder body part  102  is fixed to the bar-shaped part  103 . Here, the threaded holes  106  of the holder body part  102 , the set screws  104 , and the flat surface  107   a  of the bar-shaped part  103  constitute a fixing mechanism  108  configured to attachably and detachably fix the holder body part  102  to the bar-shaped part  103 . 
     The shank  3  is made of metal or resin. The shank  3  includes a shank-side fitted part  111  in the front end which has an outer diameter equal to that of the fitted part  13  of the grinding member holder  7 . A shank body part  112  is arranged at the rear of the shank-side fitted part  111  in the shank  3  and has the same outer diameter as that of the insertion part  107  of the grinding member holder  7 . In the outer circumferential surface on the front side of the shank body part  112 , a pair of the cut-out portions  21  cut from the outer circumference side is formed on both sides across the axial line L. Each of the cut-out portions  21  in a pair has a cut-out surface parallel to the axial line L. 
     At the center of the front end surface of the shank  3  (the front end surface of the shank-side fitted part  111 ), the circular connecting recess  22  recessed in the direction of the axial line L is formed as illustrated in  FIG. 16( b ) . In the inner circumferential surface of the annular wall  23  surrounding the connecting recess  22 , a female thread into which the tool-side threaded part  12  is screwed is formed. The connecting recess  22  is a connecting part on the shank  3  side to connect the shank  3  to the polishing tool  2 , and constitutes the connecting part  24  of the polishing tool  2  and the shank  3 , together with the tool-side threaded part  12  of the polishing tool  2 . Accordingly, when the tool-side threaded part  12  of the bar-shaped part  103  of the grinding member holder  7  is screwed into the connecting recess  22 , the polishing tool  2  is connected to the shank  3 . The shank  3  includes the shank through hole  25  penetrating in the direction of the axial line L. The front end opening of the shank through hole  25  is formed in the bottom of the connecting recess  22 . 
     The annular member  8  is made of resin, rubber, or metal. The annular member  8  is supported by the polishing tool  2  in a state that the fitted part  13  of the grinding member holder  7  and the shank-side fitted part  111  of the shank  3  are inserted into the center hole  8   a  of the annular member  8 . The outer diameter of the annular member  8  is larger than the outer diameter of the holder body part  102 . 
     The inner diameter of the center hole  8   a  of the annular member  8  is larger than the outer diameters of the fitted part  13  and the shank-side fitted part  111 , and smaller than the outer diameters of the insertion part  107  and the shank body part  112 . The length of the annular member  8  in the direction of the axial line L is shorter than the total of the length of the fitted part  13  in the direction of the axial line L and the length of the shank-side fitted part  111  in the direction of the axial line L. Hence, the annular member  8  is rotatable relative to the polishing tool  2  in a state of being fitted to the fitted part  13  and the shank-side fitted part  111 . Furthermore, the annular member  8  is movable relative to the polishing tool  2  in the direction of the axial line L in a state of being fitted to the fitted part  13  and shank-side fitted part  111 . 
     In the outer circumferential edge of the front end surface of the annular member  8 , the first tapered surface  8   b  widening backward toward the outer circumference side is formed. In the outer circumferential edge of the rear end surface of the annular member  8 , the second tapered surface  8   c  widening forward toward the outer circumference side is formed. The annular member  8  has a shape having symmetry with respect to a virtual plane perpendicular to the axial line L at the center of the annular member  8  in the direction of the axial line L. 
     In the assembly of the rotating tool  1 G, the rear end of the bar-shaped part  103  of the grinding member holder  7  is inserted into the center hole  8   a  of the annular member  8  so that the annular member  8  is held by the fitted part  13 . Thereafter, the tool-side threaded part  12  of the polishing tool  2  is screwed into the connecting recess  22  of the shank  3  so as to bring the front end surface of the annular wall  23  of the connecting recess  22  into contact with the second stage  15  between the fitted part  13  and the tool-side threaded part  12 . With this configuration, the annular member  8  is held by the fitted part  13  and the shank-side fitted part  111 . The screwing of the tool-side threaded part  12  into the connecting recess  22  is performed by engaging a tool such as a spanner in the cut-out portions  21  formed in the shank  3 . 
     The grinding member holder  7  is connected to the shank  3  to constitute the tool body  5 , so that the annular member  8  is supported by the tool body  5  in a state that the movement of the annular member  8  in the direction of the axial line L is regulated in the range of the fitted part  13  and the shank-side fitted part  111 . That is, when the annular member  8  moves forward, the annular member  8  comes into contact with the first stage  14  (the first movement-regulation part) between the fitted part  13  and the insertion part  107 , whereby the forward movement of the annular member  8  is regulated, whereas when the annular member  8  moves backward, the annular member  8  comes into contact with a stage  113  (a second movement-regulation part) between the shank body part  112  and the shank-side fitted part  111  in the shank  3 , whereby the backward movement of the annular member  8  is regulated. Furthermore, when the shank  3  is connected to the grinding member holder  7 , the shank through hole  25  of the shank  3  communicates with the holder through hole  18  of the grinding member holder  7  (the bar-shaped part  103 ). 
     The rotating tool  1 G of the present embodiment can bring about the same operational effects as the rotating tool  1  of Embodiment 1 does. The rotating tool  1 G of the present embodiment includes the plurality of grinding member bundles  101  annularly arranged around the axial line L, and is therefore more suitable for processing the hole H having a large inner diameter, compared with the rotating tool  1  of Embodiment 1. 
     Furthermore, in the present embodiment, the holder body part  102  to hold the grinding member bundles  101  is slidably supported in the direction of the axial line L by the bar-shaped part  103  of the grinding member holder  7 . Therefore, when the set screws  104  are loosened to move the holder body part  102  along the insertion part  107 , the front ends of the grinding member bundles  101  can be disposed at a desired position corresponding to the depth of the hole H to be processed. Furthermore, also in the case where the grinding member bundles  101  are worn out by processing operation, the set screws  104  are loosened to slide the holder body part  102  forward, whereby the front ends of the grinding member bundles  101  can be disposed at a desired position in the direction of the axial line L. Furthermore, when the grinding member bundles  101  are worn out, the holder body part  102  is pulled out from the bar-shaped part  103 , and the holder body part  102  (the polishing brush  105 ) can be replaced with a new one. Thus, the bar-shaped part  103  can be reused. 
     Note that the configuration of Embodiment 2 may be adopted for the connecting part  24  of the polishing tool  2  and the shank  3 . 
     Other Embodiments 
     In the embodiment above, the annular members included in the flange part  4  are movably attached relative to the grinding member holder  7  and the shank  3 , but, may be immovably attached relative to the grinding member holder  7  and the shank  3 . The annular members may be made immovable by, for example, equalizing the length of each of the annular members in the direction of the axial line L and the length of the fitted part in the direction of the axial line L. Furthermore, in the rotating tool  1 F, the annular member may be made immovable by adjusting a spacing between the first O-ring and the second O-ring which are disposed on opposite sides of the annular member. Furthermore, the flange part  4  may be integrally formed with the grinding member holder  7 , and the flange part  4  may be integrally formed with the shank  3 . Also in the case of such configurations, when the run-out on the front side of a rotating tool occurs due to the rotation of the rotating tool, a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the flange part  4 , whereby the range of the run-out of the rotating tool is regulated. 
     Note that, in the embodiment above, the tool body  5  configured by attachably and detachably connecting the shank  3  to the polishing tool  2  includes the flange part  4 , but, a tool body  5  in which the polishing tool  2  is integral with the shank  3  may include the flange part  4 . 
     Furthermore, in the embodiment above, the annular member included in the flange part  4  is attached to the tool body  5 , but, the annular member may not be attached to the tool body  5 . For example, an annular member having an outer diameter practically equal to the inner diameter of the hole H is prepared, and the outer circumferential surface of the annular member is applied as a fixed part to the peripheral wall surface of the hole H. Furthermore, the inner diameter of the center hole of the annular member is such that the tool body  5  can penetrate the hole. In this case, first, the annular member is inserted into the hole H of the workpiece W, and the annular member is fixed to the peripheral wall surface of the hole H by the fixed part. Thereafter, the tool body  5  is made to penetrate the center hole of the annular member, and rotate therein, whereby the inner circumferential surface of the hole H is processed. 
     Also with this configuration, a certain spacing between the axial line L of the tool body  5  and the peripheral wall surface of the hole H is maintained by the annular member, whereby the range of the run-out of the rotating tool can be regulated.