JP7319168B2 - friction tool - Google Patents

Description

The present invention relates to friction tools. More specifically, at the end of the body tube, there is provided a friction body made of a low-wear elastic material capable of thermally discoloring the image or handwriting by rubbing the thermochromic ink image or handwriting with the frictional heat generated at that time. Regarding friction tools.

Patent Literature 1 discloses a friction tool configured such that a friction body is slidably housed in a case body penetrating back and forth. The friction body is made of an elastic material capable of thermally discoloring the thermochromic handwriting by rubbing the thermochromic handwriting formed on the paper surface using the thermochromic ink and generating frictional heat. . The friction body has a substantially elliptical cross section and has friction portions at the front and rear ends thereof. The case body has a substantially elliptical cross section and has a window on the longer diameter side of the ellipse. The friction body is accommodated in the through-hole of the case body, and the friction part is exposed from the front or rear opening of the case body by pushing the friction body exposed through the window of the case body. It is designed to be rolled out.

Further, a projection extending in the front-rear direction is formed on the inner surface of the case body opposite to the window or on the outer surface of the friction body adjacent to the inner surface, and the friction body is attached to the projection. It is designed to be in sliding contact.

Further, the friction portion of the friction body is positioned inside the front and rear end surfaces of the case body, and protrusions are formed on the inner surfaces of the front and rear parts of the case body, and the friction body abuts on the protrusions. It is designed to be

According to the friction tool, it is possible to easily thermally discolor only the target portion of the handwriting by the thermochromic ink on the paper surface, whether it is a wide area or a narrow area, and it is possible to prevent the friction part of the friction body from being soiled. be able to. In addition, it is possible to prevent the friction body from undesirably falling out of the through hole.

JP 2013-116588 A

In the configuration disclosed in Patent Document 1, the case body and the friction body housed in the case body do not have a clip. For this reason, the friction tool has poor portability and may be lost during transportation.

The present invention is intended to solve the above-mentioned conventional problems. In addition to improving the portability of the friction tool, when the friction tool is inserted into a pocket or the like of clothes, the friction part is stored in the pocket and exposed to the outside. To provide a friction tool capable of preventing contamination of a friction part because there is no need to clean the friction part. In the present invention, "front" refers to the side of the friction portion, and "rear" refers to the opposite side.

The present invention is a friction tool comprising a friction body made of a low-wear elastic material capable of thermally discoloring an image or handwriting of a thermochromic ink by rubbing the image or handwriting generated at that time with frictional heat generated at that time, A body tube that accommodates the friction body, a friction body holding portion that is provided at the front end of the body tube and holds the friction body, and a clip that clamps an object to be clamped on the outer surface of the body tube. It is a friction tool characterized by

According to this, the portability of the friction tool is improved, and when the friction tool of the present embodiment is inserted into a pocket of clothes or the like, the friction part is stored in the pocket and is not exposed to the outside. contamination can be prevented.

In the present invention, the front end of the friction body has a cut-out edge shape in which the upper end is located forward of the lower end in a side view, and at least the front end of the friction body holding portion on the lower end side is aligned with the front end of the friction body. , are preferably parallel in side view.

According to this, it becomes easy to visually recognize the image or handwriting to be thermally discolored on the paper surface because of the cut-out blade shape in side view. In addition, the effect of suppressing excessive deformation of the front end of the cut-out blade-shaped friction body in a side view can be more effectively provided in all directions, and a form excellent in terms of design (beauty) can be provided. be able to.

Moreover, it is preferable that the front end of the upper end side of the friction body holding portion is not parallel to the front end of the friction body in a side view.

According to this, it is possible to expose the friction body only at the front end on the upper end side of the friction body holding portion, and by using the exposed portion, it is possible to thermally discolor the details.

Further, it is preferable that the friction body has a cylindrical shape extending in the axial direction, and the friction body holding portion has a cylindrical shape extending in the axial direction.

According to this, the rigidity of the friction body is increased, and the image or handwriting of the thermochromic ink can be thermally discolored efficiently at any position of the friction portion.

Further, it is preferable that the friction body has a polygonal column shape extending in the axial direction, and the friction body holding portion has a polygonal cylinder shape extending in the axial direction.

According to this, since the corner portion appears on the friction body, partial friction becomes possible, and only the portion of the thermochromic handwriting or image desired to be thermally discolored can be reliably thermally discolored.

According to the present invention, the portability of the friction tool is improved, and when the friction tool is inserted into a pocket or the like of clothes, the friction part is stored in the pocket and is not exposed to the outside. can be prevented.

1 is a side view of a friction tool in a first embodiment of the invention; FIG. 2 is a schematic longitudinal sectional view of the friction tool of FIG. 1; FIG. FIG. 2 is an enlarged view showing the vicinity of the friction body in FIG. 1; 4 is a cross-sectional view taken along line AA of FIG. 3; FIG. FIG. 5 is an enlarged view of a B portion in FIG. 4; FIG. 5 is a perspective view of a friction tool in a second embodiment of the invention; FIG. 7 is a schematic vertical cross-sectional view of the friction tool of FIG. 6; 7 is an enlarged view showing the vicinity of the friction body in FIG. 6; FIG. FIG. 9 is a cross-sectional view taken along line CC of FIG. 8; FIG. 10 is an enlarged view of part D in FIG. 9 ; FIG. 11 is a side view of a friction tool in a third embodiment of the invention;

Two embodiments of the present invention will be described below with reference to the drawings. Note that the friction tool of the present invention does not have a writing function. That is, the main body of the friction tool does not contain the thermochromic ink, and is made of a low-wear elastic material capable of thermally discoloring the image or the handwriting by rubbing the image or the handwriting of the thermochromic ink and generating frictional heat at that time. It is a friction tool provided with a friction body.

<First embodiment>
A friction tool 1 according to a first embodiment of the present invention will be described in detail with reference to FIGS. 1 to 5. FIG.

The friction tool 1 mainly includes a friction body 2 , a main tube 3 , a friction body holding portion 4 holding the friction body 2 , an operating member 5 , a delivery mechanism 6 and a clip 7 . Further, the body cylinder 2 is composed of a front shaft 31 and a rear shaft 32 . The friction body holding portion 4 is press-fitted to the front end of the front shaft 31 . An opening 41 through which the friction body 2 can protrude is provided at the front end of the friction body holding portion 4 . The friction tool 1 is provided with a delivery mechanism 6 that allows the friction body 2 to be delivered from the opening 41 by operating the operating member 5 .

Friction Body The friction body 2 is made of a low-wear elastic material that can thermally discolor the image or handwriting by rubbing the thermochromic ink image or handwriting with frictional heat generated at that time. One end (front portion 22) of the friction body 2 projects forward as the friction part 21 from a front edge 42 of a front opening 41 of the friction body holding part 4, which will be described later. A front end portion of a core rod 62 described later is connected to the other end portion (rear portion 23) of the friction body 2 in a stabbing manner.

The form of the friction tool of the present invention is not limited to the illustrated example, and may be a double-headed friction tool in which friction bodies of different shapes are attached to both ends of the friction tool. For example, one end of the friction tool is provided with a friction body made of a low-wear elastic material, and the other end of the friction tool is provided with a friction body having a lower hardness than the friction body provided at one end of the friction tool. good too. According to this, it is possible to select and use a friction body having a desired friction performance with a single friction tool.

Further, for example, one end of the friction tool may be provided with a chisel-shaped friction body, and the other end of the friction tool may be provided with a multi-sided note-shaped friction body such as a triangular prism. According to this, it is possible to select and use a friction body suitable for rubbing a friction range desired by the user with a single friction tool.

In this embodiment, the friction body 2 has a cylindrical shape extending in the axial direction, and the friction body holding portion 4 has a cylindrical shape extending in the axial direction. As shown in FIG. 2, the friction body 2 has a cylindrical front portion 22 having a friction portion 21 at its tip, and a cylindrical rear portion 23 that is connected to the front end of the core rod 62 in a stabbing manner. ing. A front portion 22 of the friction body 2 has a substantially circular cross section. According to this, the rigidity of the friction body 2 is increased, and the image or handwriting of the thermochromic ink can be thermally discolored efficiently at any position of the friction portion 21 . However, the friction body 2 (friction portion 21) is not limited to a cylindrical shape, and may be processed into other shapes such as a chisel shape, a cannonball shape, a rectangular shape, a quadrangular prism shape, a plate shape, or the like.

The elastic material constituting the friction body 2 is preferably a synthetic resin (rubber, elastomer) having elasticity. styrene copolymer), fluorine-based resins, chloroprene resins, nitrile resins, polyester-based resins, ethylene propylene diene rubber (EPDM), and the like. The elastic synthetic resin that constitutes the friction body 7 is made of a low-wear elastic material that produces almost no wear residue (eraser residue) during friction, rather than a high-wear elastic material (such as an eraser). It is preferable to be

Moreover, preferably, the friction body 2 is detachable from the friction tool 1 . As a result, when the friction body 2 becomes soiled or the like, it can be easily replaced with a new friction body. Also, the user can select and replace the desired shape of the friction body for use.

· Friction Body Holding Portion The friction body holding portion 4 that holds the friction body 2 is provided at the front end of the main body tube 3 . A front edge portion 42 of the friction body holding portion 4 is provided with an opening 41 through which the friction body 2 can protrude. In this embodiment, the friction body holding portion 4 is formed of a tubular body obtained by processing a thin metal plate. However, the material constituting the friction body holding portion 4 is not limited to metal, and examples thereof include synthetic resin (eg, polyacetal resin, polypropylene resin, polycarbonate resin, ABS resin), paper, and the like.

Further, it is effective that the thickness of the friction body holding portion is 0.1 mm or more and 1.0 mm or less, preferably 0.15 mm or more and 0.5 mm or less. Within such a preferable range, the desired strength of the friction body holding portion can be obtained, the thermally discolored image or handwriting can be easily seen on the paper surface, and a form excellent in design (aesthetics) can be provided. be able to. As a specific example of dimensions, the thickness of the friction body holding portion 4 is 0.3 mm if the material of the friction body holding portion 4 is metal, and 0.6 mm if the material is synthetic resin.

Also, the friction body holding portion 4 may be formed integrally with the main body tube 3 . That is, the friction body holding portion 4 may be integrally formed with the main body tube 3 by two-color molding, insert molding, or the like. Alternatively, the front end portion of the main tube 3 may also serve as the friction body holding portion.

An opening 41 through which the friction body 2 can protrude is provided at the front end of the friction body holding portion 4 . It is effective that the gap G1 between the opening 41 and the friction body 2 is 0.03 mm or more and 0.5 mm or less, preferably 0.03 mm or more and 0.3 mm or less. Within such a preferable range, it is possible to suppress "rattling" of the friction body 2 at the time of rubbing, and obtain a good feeling of friction and heat discoloration performance.

Moreover, it is preferable that the gap G1 between the opening 41 and the friction body 2 is substantially constant. According to this, the opening can effectively provide the effect of suppressing the "rattling" of the friction body during friction in all directions. In addition, it is possible to provide an excellent form in terms of design (beauty).

·Main body tube In this embodiment, the main body tube 3 is a cylindrical body with both ends opened, and is obtained by injection molding of a synthetic resin (for example, polypropylene resin, polycarbonate resin, ABS resin, etc.). Note that the main tube 3 may be made of metal. As shown in FIG. 2, the main tube 3 is composed of a front shaft 31 and a rear shaft 32. The inner surface of the rear end portion of the front shaft 31 is screwed with the outer surface of the front end portion of the rear shaft 32 (male screw portion 33). A female threaded portion 34 is formed. Further, the main tube 3 accommodates the friction body 2 and has a delivery mechanism that allows the friction body 2 to be delivered inside the main tube.

The body tube 3 may have a direction identifying portion for identifying the direction of the friction body 2 on its outer surface. For example, the orientation identifier may be provided by an axially extending projection. In this case, it is not necessary to visually confirm the orientation of the friction body 2 immediately before rubbing, and the friction can be performed immediately after the friction body 2 is exposed.

- Delivery Mechanism The friction tool 1 has a delivery mechanism 6 that enables the friction body 2 to be delivered from the opening 41 by operating the operation member 5 . In the feeding mechanism 6 of the present embodiment, when the operation member 5 provided at the rear portion of the main tube 3 is operated forward in the axial direction, the chuck 61 provided inside the main tube 3 advances and moves the friction body 2. It is characterized in that it can be drawn out by a predetermined amount. The delivery mechanism 6 of the first embodiment of the present invention will be described in detail below with reference to FIG.

In the feeding mechanism 6 of the present embodiment, the chuck 61 and the connector 67 are connected by press-fitting and fixing the connector 67 to the rear portion of the chuck 61 disposed inside the main body cylinder 3. The connector 67 and the wick tank are connected by press-fitting and fixing the wick tank 68 . The rear part of the core rod 62 is accommodated in the lead tank 68 , and the operation member 5 is press-fitted and fixed to the rear part of the lead tank 68 .

A front portion of the chuck 61 is divided into a plurality of parts, and a ring-shaped fastener 64 is fitted to the front portion of the chuck 61 . An elastic body 65 is tightly fitted between the partition wall 35 that receives the rear end of the fastener 64 and the front end of the connector 67 , and the front part of the chuck 61 urged rearward by the elastic body 65 holds the core rod 62 . ing. A guide sleeve 66 is provided inside the front shaft 31 , and the core rod holder 63 is arranged inside the guide sleeve 66 . A core rod holder 63 holds a core rod 62 connected to the friction body 2 .

When the friction member 2 is adjusted to the amount of protrusion desired by the user, the operation member 5 is pushed forward against the elastic force of the elastic member 65, and the operation member 5 is connected. Then, the lead tank 68 moves forward, the chuck 61 moves forward while gripping the core rod 62, the fastener 64 abuts against the inner surface of the guide sleeve 66 and stops moving, and the fastener 64 contacts the chuck. The core rod 62 is extended until it is released from the front and the front of the chuck is expanded. Even if the front portion of the chuck 61 expands, the core rod 62 is held by the core rod holder 63 , so the friction body 2 connected to the core rod 62 does not drop from the friction tool 1 . When the pressing of the operating member 5 is stopped, the lead tank 68 is moved rearward by the elastic force of the elastic body 65, the chuck 61 is moved rearward, and the fastener 64 comes into contact with the front end of the partition wall 35 to stop and chuck. 61, the front portion of the chuck 61 is closed, and the friction body 2 connected to the core rod 62 is fixed to enable friction.

It should be noted that the feeding mechanism of the friction tool of the present invention is not limited to the illustrated example of the present embodiment. For example, it comprises the body tube having a spiral groove on its inner surface, an inner tube rotatably provided in the body tube, and a slider having a support portion for gripping the friction body. A member may be integrally formed with the inner cylinder, and rotating the operation member in the circumferential direction may cause the slider to move forward, thereby allowing the friction body to be delivered.

Further, for example, a sliding groove extending in the axial direction in the main tube, a plurality of locking grooves intersecting with the sliding groove, and an axial groove built in the main tube and integrally formed with the operating member. and a protrusion formed on the retainer, the protrusion being engageable with the locking groove, the friction body being gripped by the retainer, The feeding mechanism may be characterized in that the holder moves forward by operating the operating member in the axial direction, and the friction body can be fed out by a predetermined amount.

Further, for example, a plurality of cam teeth and cam grooves formed on the inner surface of the main body cylinder and alternately arranged along the circumferential direction and extending in the front-rear direction, a holder to which the friction body is fixed at the front end, the holder and a rotating member having a plurality of ridges alternately engageable with the cam teeth or the cam grooves, and a plurality of rotating members formed integrally with the operating member for rotating the rotating member. and a plurality of engaging projections engaged with the cam grooves on the inner surface of the main body cylinder so as to move back and forth; and an elastic body for urging the holder backward, The holder is housed inside the main tube and is movable in the axial direction of the main tube, and the friction body can be moved in and out of the main tube as the holder moves. It may be a feeding mechanism with a feature.

·Clip In this embodiment, a clip 7 is provided on the outer surface of the operation member 5 for clamping an object to be clamped . The clip 7 has a base portion connected to the operating member, a clip portion extending in the axial direction, and a clamping portion for clamping an object to be clamped in the front portion of the clip 7. The clip 7 opens forward in the axial direction. there is As a result, the portability of the friction tool is improved, and when the friction tool of the present embodiment is inserted into a pocket or the like of clothes, the friction part is stored in the pocket and is not exposed to the outside. can be prevented.

(Action and effect of the first embodiment of the friction tool)
The friction tool 1 configured as described above can produce the following effects.

According to this embodiment, the feeding mechanism 6 is provided so that the friction body 2 can be fed out from the opening 41 by operating the operation member 5 that can be operated in the longitudinal direction or in the rotational direction with respect to the main tube 3 . As a result, the friction body 2 can be extended with a desired force and by a desired amount.

In addition, by setting the gap G1 between the opening 41 and the friction body 2 in an appropriate range, it is possible to suppress the "rattling" of the friction body 2 during friction, thereby providing good friction feeling and thermal discoloration performance. is obtained.

Further, since the gap G1 between the opening 41 and the friction body 2 is substantially constant, the effect of suppressing the "rattling" of the friction body 2 during friction can be obtained in all directions by the opening 41. can be effectively provided in In addition, it is possible to provide an excellent form in terms of design (beauty).

The friction body has a columnar shape extending in the axial direction, and the friction body holding portion has a cylindrical shape extending in the axial direction. According to this, the rigidity of the friction body is increased, and the image or handwriting of the thermochromic ink can be thermally discolored efficiently at any position of the friction portion.

The friction body has a polygonal columnar shape extending in the axial direction, and the friction body holding portion has a polygonal cylinder shape extending in the axial direction. According to this, since the corner portion appears on the friction body, partial friction becomes possible, and only the portion of the thermochromic handwriting or image desired to be thermally discolored can be reliably thermally discolored.

Further, the front end of the friction body has a cutting edge shape with the upper end located forward of the lower end in side view, and at least the front end on the lower end side of the friction body holding portion is parallel to the front end of the friction body in side view. It has become. According to this, it becomes easy to visually recognize the image or handwriting to be thermally discolored on the paper surface because of the cut-out blade shape in side view. In addition, the effect of suppressing excessive deformation of the front end of the cut-out blade-shaped friction body in a side view can be more effectively provided in all directions, and a form excellent in terms of design (beauty) can be provided. be able to.

Further, the front end on the upper end side of the friction body holding portion is not parallel to the front end of the friction body in a side view. According to this, it is possible to expose the friction body only at the front end on the upper end side of the friction body holding portion, and by using the exposed portion, it is possible to thermally discolor the details.

<Second embodiment>
The friction tool 101 according to the second embodiment of the present invention will be described in detail with reference to FIGS. 6 to 10. FIG.

In the second embodiment of the present invention, the cross-sectional shape of the friction body 102, the side view shape of the friction body 102, and the attachment position of the clip 107 are different from those of the first embodiment. Other configurations of the second embodiment are substantially the same as those of the friction tool 1 of the first embodiment. 6 to 10, the same components as in the first embodiment are denoted by the same reference numerals, and detailed description thereof will be omitted.

Friction Body In the present embodiment, the friction body 102 has a polygonal column shape extending in the axial direction, and the friction body holding portion 104 has a polygonal cylinder shape extending in the axial direction. As shown in FIG. 7, the friction body 102 includes a polygonal prism-shaped front portion 122 having a friction portion 121 at its tip, and a polygonal prism-shaped rear portion 123 that is connected to the front end of the core rod 62 in a stabbing manner. have. The front portion 122 of the friction body 102 has a generally polygonal cross section. According to this, since the corner portion appears on the friction body 102, partial friction becomes possible, and only the portion of the thermochromic handwriting or image desired to be thermally discolored can be reliably thermally discolored. However, the friction body 102 (friction portion 121) is not limited to a polygonal prismatic shape, and may be processed into other shapes such as a chisel shape, cannonball shape, rectangular shape, square prism shape, plate shape, etc., according to the purpose. .

The front end of the friction body 102 has a cut-out edge shape in which the upper end is located forward of the lower end in a side view, and at least the front end of the friction body holding portion 104 on the lower end side is aligned with the front end of the friction body 102 in a side view. parallel. According to this, it becomes easy to visually recognize the image or handwriting to be thermally discolored on the paper surface because of the cut-out blade shape in side view. In addition, the effect of suppressing excessive deformation of the front end of the cut-out edge-shaped friction body in a side view can be more effectively provided in all directions.

If only the front end of the friction body 102 had a cutting edge shape and the front end of the friction body holding portion 104 (that is, the front edge portion 142) was non-parallel to the front end of the friction body 102, the friction body 102 The protruding length of the friction body from the front edge portion 142 becomes uneven, and the degree of deflection of the friction portion varies depending on the contact portion of the friction portion 121 with the paper surface, which may prevent uniform thermal discoloration.

Moreover, it is preferable that the front end of the upper end side of the friction body holding portion is not parallel to the front end of the friction body in a side view.

According to this, it is possible to expose the friction body only at the front end on the upper end side of the friction body holding portion, and by using the exposed portion, it is possible to thermally discolor the details. Here, the "front end on the upper end side of the friction body holding portion" in this embodiment is shown as a non-parallel portion 143 in FIG.

·Clip In this embodiment, a clip 107 for clamping an object to be clamped is provided on the outer surface of the main tube 3 (specifically, the rear shaft 32). The clip 107 has a base portion connected to the rear shaft 32, a clip portion extending in the axial direction, and a holding portion for holding an object to be held in the front portion of the clip 107. The clip 107 opens forward in the axial direction. ing. As a result, the portability of the friction tool is improved, and when the friction tool of the present embodiment is inserted into a pocket or the like of clothes, the friction part is stored in the pocket and is not exposed to the outside. can be prevented.

Moreover, a clip 107 for holding an object to be held may be provided on the outer surface of the main tube 3 (specifically, the front shaft 31). The clip 107 has a base portion connected to the front shaft 31, a clip portion extending in the axial direction, and a clamping portion for clamping an object to be clamped at the rear portion of the clip 107. The clip 107 opens toward the rear in the axial direction. good too.

In this case, when gripping the body tube 3 (front shaft 31) and rubbing the thermochromic ink image or handwriting, the vicinity of the clip 107 is gripped with fingers, and the orientation of the friction portion 121 and the orientation of the paper surface naturally occur. It is possible to grasp the grounding situation. That is, the clip 107 has a direction identifying function for identifying the orientation of the friction body 2. FIG. In this case, it is not necessary to visually confirm the orientation of the friction body 2 immediately before rubbing, and the friction can be performed immediately after the friction body 2 is exposed.

<Third Embodiment>
Referring to FIG. 11, the friction tool 201 according to the third embodiment of the invention will be described in detail.

The friction tool 201 shown in FIG. 11 includes a friction body 202 made of a low-wear elastic material capable of thermally discoloring the image or handwriting by rubbing the thermochromic ink image or handwriting with the frictional heat generated at that time. A friction tool characterized in that the friction body 202 has a clip function for clamping an object to be clamped , and the clip 207 contains a low-wear elastic material at least in part. .

For example, as shown in FIG. 11, the friction tool 201 has a friction body 202 having a clip function for holding an object to be held, and a friction part 221 made of a low-wear elastic material at the top of the clip 207. may Alternatively, the entire clip 207 may be the friction portion 221 made of an elastic material. As a result, the locations of the friction tool 201 that can be rubbed are diversified, and various usage methods desired by the user can be accommodated. The clip is obtained by injection molding of metal or synthetic resin (eg, polypropylene resin, polycarbonate resin, ABS resin, etc.). As a result, the portability of the friction tool is further improved, and the clip function is also improved, thereby improving the convenience.

1, 101, 201 Friction implements 2, 102, 202 Friction bodies 21, 121, 221 Friction parts 22, 122 Front parts 23, 123 Rear part 3 Main tube 31 Front shaft 32 Rear shaft 33 Male screw 34 Female screw 35 Partition wall 4 , 104 friction body holding portions 41, 141 openings 42, 142 front edge portion 145 non-parallel portions G1, G2 interval 5 operation member
6 feeding mechanism 61 chuck 62 core rod 63 core rod holder 64 fastener 65 elastic body 66 guide sleeve 67 connector 68 core tank 7, 107, 207 clip

Claims (3)

A friction tool comprising a friction body made of a low-wear elastic material capable of thermally discoloring the image or handwriting by rubbing an image or handwriting of thermochromic ink and generating frictional heat,
a main tube that accommodates the friction body; a friction body holding portion that is provided at the front end of the main tube and holds the friction body; and a clip that clamps an object to be clamped on the outer surface of the main tube. ,
The front end of the friction body has a cutting edge shape in which the upper end is located forward of the lower end in side view, and at least the front end on the lower end side of the friction body holding portion are parallel,
A friction tool , wherein the front end of the upper end side of the friction body holding portion is non-parallel to the front end of the friction body in a side view . 2. The friction tool according to claim 1 , wherein said friction body has a cylindrical shape extending in the axial direction, and said friction body holding portion has a cylindrical shape extending in the axial direction. 2. The friction tool according to claim 1 , wherein said friction body has a polygonal prismatic shape extending in the axial direction, and said friction body holding portion has a polygonal cylindrical shape extending in the axial direction.

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