Abrasive brush and method of abrading

Abstract

A polishing brush (1) has a rod-shaped member (2) and an abrasive bundle (4) composed of a plurality of linear abrasives (3). The rod-shaped member (2) has a holding hole (6) that holds the abrasive bundle (4) at a front side portion (2a). The holding hole (6) has a bottom surface (7) and a cylindrical peripheral wall surface (8) that extends from the bottom surface (7) in a tilt direction (S). The abrasive bundle (4) has a housed portion (4a) that is housed in the holding hole (6) and a protruding portion (4b) that protrudes from an opening (6a) of the holding hole (6) in the tilt direction (S). A front end of the protruding portion (4b) is located outside the rod-shaped member (2) when viewed in a direction from an axis (L0).

Description

TECHNICAL FIELD

[0001] The present disclosure relates to an abrasive brush provided with a linear abrasive bundle and an abrasive method using the abrasive brush. BACKGROUND

[0002] Patent Document 1 describes an abrasive brush provided with an abrasive bundle in which linear abrasives are bundled. The abrasive brush of this document is provided with a brush-shaped grindstone having an abrasive bundle and a rod-shaped polishing device that holds the brush-shaped grindstone. The polishing device is provided with a holding portion that holds the brush-shaped grindstone at a front end portion. The brush-shaped grindstone held in the holding portion projects the abrasive bundle forward from the front end of the rod-shaped member. The projecting direction of the abrasive bundle is the axial direction of the polishing device.

[0003] PRIOR ART DOCUMENTS

[0004] PATENT DOCUMENT

[0005] Patent Document 1: Japanese Patent Application Publication No. 2004-142042 SUMMARY

[0006] PROBLEMS TO BE SOLVED BY THE INVENTION

[0007] In the case of polishing the inner peripheral surface of a pipe member using the abrasive brush described in Patent Document 1, the axis of the polishing device is inclined with respect to the pipe axis to insert the abrasive bundle into the workpiece. Thereby, the front end portion of the abrasive bundle is brought into contact with the inner wall surface of the pipe member. In this case, in the case where it is intended to polish the inner peripheral surface of the pipe member to a deep portion using the abrasive brush described in Patent Document 1, the polishing device inclined with respect to the pipe axis can be interfered with by the opening rim of the pipe member, and there is a problem that the front end portion of the abrasive bundle cannot reach the deep portion of the pipe member.

[0008] In view of this point, the technical problem of the present invention is to provide an abrasive brush that can avoid interference with the opening rim of a pipe member when polishing the inner peripheral surface of the pipe member, and the like. Further, an abrasive method using the abrasive brush is proposed.

[0009] TECHNICAL SOLUTION

[0010] To solve the above-described technical problem, the abrasive brush of the present application is characterized by having: an abrasive bundle composed of a plurality of linear abrasives; and a rod-shaped member, when a direction along an axis of the rod-shaped member is set as an axial direction, a direction orthogonal to the axis is set as a radial direction, a direction intersecting the axial direction and the radial direction is set as an oblique direction, one of the axial direction is set as a front side, and the other is set as a rear side, the rod-shaped member has a holding hole holding the abrasive bundle at a front side portion thereof, the holding hole has a bottom surface, a cylindrical peripheral wall surface extending from the bottom surface to the oblique direction, and an opening toward one direction of the radial direction, the abrasive bundle has a housed portion housed in the holding hole and a protruding portion protruding from the opening of the holding hole to the oblique direction, an oblique angle formed by a hole axis of the holding hole and the axis is 45° or less, and a front end portion of the protruding portion is located outside the rod-shaped member when viewed from the axial direction. In addition, in the present application, the abrasive bundle can be one.

[0011] According to the present application, the abrasive bundle is held in the holding hole extending to the oblique direction and protrudes from the opening of the holding hole to the oblique direction. In addition, in the abrasive bundle, the front end of the protruding portion protruding from the holding hole is located outside the rod-shaped member when viewed from the axial direction. Therefore, in the case of the inner peripheral surface of the pipe member, the abrasive bundle can be inserted into the pipe member with the axis of the rod-shaped member parallel to the pipe axis of the pipe member, and the front end portion of the abrasive bundle can be brought into contact with the inner wall surface. Here, as long as the axis of the rod-shaped member is parallel to the pipe axis of the pipe member, the opening edge of the rod-shaped member and the opening edge of the pipe member do not interfere with each other. In addition, the holding hole holding the abrasive bundle is provided at the front side portion of the rod-shaped member. Therefore, the rear end portion of the rod-shaped member can be connected to the machine tool. Thus, the rod-shaped member can be inserted into the pipe member to a deep portion. Therefore, the inner peripheral surface of the pipe member can be polished to a deep portion by the abrasive brush. In addition, the peripheral wall surface of the holding hole of the rod-shaped member holding the abrasive bundle extends in the oblique direction. Therefore, if the abrasive bundle is held in the holding hole, the abrasive bundle can protrude in the oblique direction. In addition, if the oblique angle of the abrasive bundle is 45° or less, the abrasive bundle is easily bent to the axial side when polishing the inner peripheral surface of the pipe member. Therefore, it is possible to prevent or suppress the inner peripheral surface of the pipe member from being excessively polished by the front end portion of the abrasive bundle.

[0012] In the present application, the peripheral wall surface of the holding hole can have a peripheral wall surface portion that opposes the accommodation portion from the inner side of the radial direction compared to the hole axis of the holding hole. In this way, when the front end portion of the protruding portion of the abrasive beam is brought into contact with the inner peripheral surface of the pipe member in order to grind the inner peripheral surface of the pipe member, even in the case where the abrasive beam is deflected in the direction approaching the axis under the action of the load acting on the abrasive beam from the inner peripheral surface of the pipe member, the deflection range of the abrasive beam can be limited by the peripheral wall surface portion of the holding hole. Therefore, the grinding force of the abrasive beam that grinds the inner peripheral surface of the pipe member can be maintained.

[0013] Here, in the case where the entire region of the peripheral wall surface portion of the holding hole is in contact with the accommodation portion of the abrasive beam, when the abrasive beam is deflected under the action of the load acting on the abrasive beam from the inner peripheral surface of the pipe member, there is a problem in that the abrasive beam is easily broken from the portion thereof that abuts against the opening rim of the holding hole. In view of such a problem, in the present application, it is desirable that the opening side region of the peripheral wall surface portion that is a prescribed width from the opening opposes the accommodation portion with a gap. In this way, when a load acts on the abrasive beam from the inner peripheral surface of the pipe member, the abrasive beam is allowed to be deflected within the holding hole. Therefore, it is possible to prevent or inhibit the case where the abrasive beam is broken from the portion thereof that abuts against the opening rim of the holding hole.

[0014] In the present application, it is desirable that there be an abrasive beam holder that holds the end portion of the accommodation portion on the side opposite to the protruding portion, and the abrasive beam is detachably held in the holding hole by the abrasive beam holder. In this way, the brush-like grinding stone constituted by the abrasive beam holder and the abrasive beam held in the abrasive beam holder can be attached to and detached from the rod-like member. Therefore, when the abrasive beam is worn due to grinding of the inner peripheral surface of the pipe member, a new brush-like grinding stone can be replaced.

[0015] In the present application, it can be provided that the abrasive beam holder has a cylindrical portion that surrounds the end portion of the accommodation portion on the side opposite to the protruding portion from the outer peripheral side, and a bottom portion that seals the opening of one side of the cylindrical portion, the bottom portion abutting against the bottom surface, the cylindrical portion being in contact with the peripheral wall surface portion of the holding hole on the side of the bottom surface from the opening side region. In this way, the bottom portion of the abrasive beam holder that holds the abrasive beam is brought into abutment with the bottom surface of the holding hole, whereby the brush-like grinding stone can be held to the rod-like member. Further, in the case where the brush-like grinding stone is held to the holding hole, the exposed portion of the abrasive beam that is exposed from the cylindrical portion within the holding hole is separated from the holding hole by a gap of an amount of the thickness of the cylindrical portion from the peripheral wall surface portion of the holding hole. Therefore, as long as the brush-like grinding stone is held to the holding hole, the opening side region of the peripheral wall surface portion can be separated from the accommodation portion.

[0016] In the present application, it is desirable to have a screw fixing mechanism that fixes the abrasive beam holder to the rod-shaped member in a state where it cannot rotate around the hole axis of the holding hole. In this way, the inner peripheral surface of the pipe member can be polished with high accuracy compared to a case where the brush-shaped grindstone held in the holding hole rotates around the hole axis.

[0017] In this case, it can be provided that the cylindrical portion is a cylindrical shape, the bottom portion is a disc shape, and the screw fixing mechanism has a fixing screw, a screw hole that penetrates the bottom portion in a direction orthogonal to the hole axis of the holding hole, and a fixing hole that extends in the rod-shaped member in a direction orthogonal to the hole axis of the holding hole and penetrates the holding hole from the outside of the rod-shaped member, and the fixing screw penetrates the bottom portion by being screwed into the screw hole through the fixing hole so as to abut against the peripheral wall surface. In this way, the brush-shaped grindstone held in the holding hole can be fixed to the holding member in a state where it cannot rotate around the hole axis of the holding hole. Furthermore, the screw hole penetrates the abrasive beam holder, so when the front end portion of the abrasive beam is worn due to polishing of the inner peripheral surface of the pipe member, the brush-shaped grindstone can be rotated 180° around the hole axis and reused. That is, when the front end portion of the abrasive beam is worn, the fixing screw is removed from the opening of one side of the screw hole, the brush-shaped grindstone is rotated 180° around the hole axis of the holding hole, and then the fixing screw is screwed into the screw hole from the opening of the other side of the screw hole. As a result, in the brush-shaped grindstone, the face on the outer side in the radial direction of the abrasive beam is replaced. As a result, in the front end portion of the abrasive beam, the portion that is less worn can be brought into contact with the inner peripheral surface of the pipe member, so the brush-shaped grindstone can be reused.

[0018] In the present application, the tubular portion can be cylindrical, the bottom portion can be disc-shaped, the screw fixing mechanism can include a fixing screw, a screw hole that penetrates the bottom portion in a direction orthogonal to the hole axis of the holding hole, and a fixing hole that extends in the rod-shaped member in a direction orthogonal to the hole axis of the holding hole and penetrates the holding hole from the outside of the rod-shaped member, the fixing screw can include a shaft portion that has a male screw that can be screwed into the screw hole on an outer peripheral surface, and a head portion that is provided at an end portion of one side of the shaft portion, the shaft portion is screwed into the screw hole through the fixing hole, and the head portion abuts against the rod-shaped member from the outer peripheral side. In this way, the brush-shaped grinding stone that is held in the holding hole can be fixed to the holding member in a state in which it cannot rotate around the hole axis of the holding hole. In addition, the screw hole penetrates the abrasive bundle support, so when the front end portion of the abrasive bundle is worn due to polishing of the inner peripheral surface of the pipe member, the brush-shaped grinding stone can be rotated 180° around the hole axis to be used again. That is, when the front end portion of the abrasive bundle is worn, the fixing screw is removed from one opening of the screw hole, the brush-shaped grinding stone is rotated 180° around the hole axis of the holding hole, and then the fixing screw is screwed into the screw hole from the other opening of the screw hole. As a result, in the brush-shaped grinding stone, the face on the outer side in the radial direction of the abrasive bundle is replaced. As a result, in the front end portion of the abrasive bundle, the portion that is less worn can be brought into contact with the inner peripheral surface of the pipe member, so the brush-shaped grinding stone can be used again.

[0019] In the present application, the tubular portion can be cylindrical, the screw fixing mechanism can include a fixing screw and a screw hole that extends in the rod-shaped member in a direction orthogonal to the hole axis of the holding hole, the screw hole can include a communication portion that communicates with the holding hole at a portion in the circumferential direction of the screw hole, the fixing screw can include a protruding portion of the fixing screw that protrudes into the holding hole from the communication portion when screwed into the screw hole, and the protruding portion of the fixing screw can abut against the tubular portion from the opening side of the holding hole in the inclined direction. In this way, the brush-shaped grinding stone that is held in the holding hole can also be fixed to the holding member in a state in which it cannot rotate around the hole axis of the holding hole. In addition, when the fixing screw is removed from the screw hole, the abutting state between the protruding portion of the fixing screw and the tubular portion of the abrasive bundle support is released, so the brush-shaped grinding stone can be rotated at an arbitrary angle around the hole axis. Therefore, when the front end portion of the abrasive bundle is worn due to polishing of the inner peripheral surface of the pipe member, the brush-shaped grinding stone can be rotated around the hole axis to bring the portion that is less worn into contact with the inner peripheral surface of the pipe member in the front end portion of the abrasive bundle. As a result, the brush-shaped grinding stone can be used again.

[0020] In the present application, the rod-shaped member can be provided with a small-diameter hole that has an inner diameter smaller than that of the holding hole and extends linearly from the bottom surface to the side opposite the opening of the holding hole and penetrates the rod-shaped member. If such a small-diameter hole is provided, when the brush-shaped grindstone is held in the holding hole, air in the holding hole can escape to the outside through the small-diameter hole. Therefore, it is easy to hold the brush-shaped grindstone in the holding hole. Furthermore, by inserting a pin into the small-diameter hole and bringing the abrasive beam support into contact with the bottom surface of the holding hole, and then projecting the tip of the pin into the holding hole, the brush-shaped grindstone can be pushed out toward the opening side of the holding hole. Therefore, it is easy to detach the brush-shaped grindstone.

[0021] In the present application, the holding hole can be provided with a second opening that communicates the holding hole with the outside of the rod-shaped member at a portion of the peripheral direction of the annular corner portion where the peripheral wall surface intersects the bottom surface, and a support corner portion of the abrasive beam support that includes a portion of the peripheral direction of the bottom portion is exposed to the outside from the rod-shaped member through the second opening. If the holding hole is provided with a second opening, when the brush-shaped grindstone is held in the holding hole, air in the holding hole can escape to the outside through the second opening. Therefore, it is easy to hold the brush-shaped grindstone in the holding hole. Furthermore, when the brush-shaped grindstone is held in the holding hole, the abrasive beam support can be visually confirmed through the second opening. Therefore, it is possible to confirm whether the brush-shaped grindstone is reliably held in the holding hole by visual confirmation. Furthermore, by pressing the support corner portion of the abrasive beam support that is exposed to the outside of the rod-shaped member from the second opening in the inclined direction, the brush-shaped grindstone can be pushed out toward the opening side of the holding hole. Therefore, it is easy to detach the brush-shaped grindstone.

[0022] In this case, it is desirable that, when viewed from a normal direction perpendicular to an imaginary plane that includes the axis and the hole axis of the holding hole, the rod-shaped member have a cutout portion on the side opposite the opening of the holding hole with the axis interposed therebetween, the second opening open on the inside of the cutout portion, and the support corner portion located on the inside of the cutout portion. In this way, when the polishing brush is inserted into the pipe member, it is possible to prevent the support corner portion of the abrasive beam support exposed to the outside from the rod-shaped member from being interfered with by the opening rim or the like of the pipe member.

[0023] In the present application, the rod-shaped member can be provided with a front-side opening provided on the rear side of the opening of the front-side portion of the rod-shaped member, a rear-side opening provided on the rear end portion of the rod-shaped member, and an internal flow path that communicates the front-side opening with the rear-side opening. In this way, air or coolant can be supplied from the rear-side opening provided on the rear-side portion of the rod-shaped member to the abrasive beam side through the internal flow path.

[0024] In the present application, the protruding portion can protrude from the opening of the holding hole toward the front. In this case, the protruding portion of the abrasive beam extends toward the front, and thus, when the inner peripheral surface of the pipe member is polished, the tip end portion of the abrasive beam can reach a deep portion of the pipe member.

[0025] In this case, the rod-shaped member can be provided with a recess that is located at the rear of the opening at a front side portion of the rod-shaped member when viewed in a normal direction that is perpendicular to a virtual plane that includes a hole axis of the holding hole and the axis, a front end surface of the rod-shaped member is parallel to the hole axis when viewed in the normal direction, and the recess has an inclined surface that is inclined toward the side on which the axis is located from the side of the opening toward the rear when viewed in the normal direction, and the front end surface is parallel to the inclined surface. In this case, the rod-shaped member is held in a predetermined posture by gripping a portion between the front end surface and the inclined surface of the rod-shaped member by the jig, and thus, the abrasive beam is easily held in the holding hole of the rod-shaped member held by the jig.

[0026] In the present application, the protruding portion can protrude from the opening of the holding hole toward the rear. In this case, the protruding portion of the abrasive beam extends toward the rear. Thus, for example, in a case where the pipe member has a ring-shaped stepped portion in the inner peripheral surface, if the polishing brush is inserted into the pipe member and the abrasive beam is arranged at a position deeper than the stepped portion, the stepped portion can be polished from the deep side of the pipe member.

[0027] In the present application, the end portion on the outer side of the abrasive beam can be parallel to the axis when viewed in a normal direction that is perpendicular to a virtual plane that includes a hole axis of the holding hole and the axis. In this case, when the inner peripheral surface of the pipe member is polished, the tip end portion of the abrasive beam can contact the inner peripheral surface with a relatively wide area.

[0028] In the present application, the tip end portion of the protruding portion can have a conical shape that becomes thin toward the tip end side in the inclined direction. In this case, when the inner peripheral surface of the pipe member is polished, the tip end portion of the abrasive beam can contact the inner peripheral surface with a relatively wide area. In this case, the tip end portion of the abrasive beam is easily adjusted to a conical shape, and thus, the abrasive beam whose tip end portion is inclined is easily manufactured.

[0029] In the present application, the angle of inclination at which the hole axis of the holding hole and the axis intersect can be 15° or more. If the angle of inclination is 15° or more, the tip end portion of the abrasive beam is easily brought into contact with the inner peripheral surface of the pipe member on the outer peripheral side of the rod-shaped member.

[0030] Next, in the present application, a polishing method for polishing an inner peripheral surface of a tubular portion of a workpiece using the above-described polishing brush is characterized in that an axis of the rod-shaped member is made parallel to a tube axis of the tubular portion, and the abrasive beam is inserted into the tubular portion, and the workpiece is rotated around the tube axis in a state where the abrasive beam contacts the inner peripheral surface.

[0031] Further, as another aspect of the present application, a polishing method for polishing an inner peripheral surface of a tubular portion of a workpiece using the above-described polishing brush is characterized in that an axis of the rod-shaped member is made parallel to a tube axis of the tubular portion, and the abrasive beam is inserted into the tubular portion, and the workpiece is rotated around the tube axis in a state where the abrasive beam contacts the inner peripheral surface.

[0032] Effects of Invention

[0033] In the present application, the holding hole that holds the abrasive beam is provided at the front side portion of the rod-shaped member. Further, if the axis of the rod-shaped member is made parallel to the tube axis of the tube member that is the polishing object, the rod-shaped member and the opening edge of the tube member do not interfere with each other. Therefore, the rod-shaped member can be inserted into the deep portion of the tube member. Therefore, the inner peripheral surface of the tube member can be polished by the polishing brush up to the deep portion. Further, when the front end portion of the protruding portion of the abrasive beam is made to contact the inner peripheral surface of the tube member in order to polish the inner peripheral surface of the tube member, the abrasive beam can be flexed. Therefore, the polishing force of the abrasive beam that polishes the inner peripheral surface of the tube member can be maintained. BRIEF DESCRIPTION OF DRAWINGS

[0034] Figure 1 is a perspective view of the polishing brush in a case where it is observed from the side of the protruding side of the abrasive beam.

[0035] Figure 2 is a perspective view of the polishing brush in a case where it is observed from the rear side.

[0036] Figure 3 is a perspective view of the polishing brush in a case where it is observed from the side opposite to the abrasive beam.

[0037] Figure 4 is a rear view of the polishing brush.

[0038] Figure 5 is a sectional view of the polishing brush after being cut along the axis of the rod-shaped member.

[0039] Figure 6 is a perspective view of the brush-shaped grindstone.

[0040] Figure 7 is an explanatory view of a screw fixing mechanism that fixes the brush-shaped grindstone to the rod-shaped member.

[0041] Figure 8 is an explanatory view of a polishing method based on the polishing brush.

[0042] Figure 9 is a diagram of a polishing method which is a modification example.

[0043] Figure 10 is a diagram of a polishing brush which is a modification example 1.

[0044] Figure 11 is a diagram of a polishing brush which is a modification example 2.

[0045] Figure 12 is a perspective view of a polishing brush which is a modification example 3, as viewed from the abrasive bundle side.

[0046] Figure 13 is a perspective view of a polishing brush which is a modification example 3, as viewed from the opposite side. Figure 12

[0047] Figure 14 is a cross-sectional view of a polishing brush which is a modification example 3.

[0048] Figure 15 is a diagram of a polishing brush which is an embodiment 2.

[0049] Figure 16 is a diagram of a polishing brush which is an embodiment 3.

[0050] Figure 17 is a perspective view of a polishing brush which is an embodiment 4, as viewed from the abrasive bundle side.

[0051] Figure 18 is a cross-sectional view of a polishing brush which is an embodiment 4.

[0052] Figure 19 is a diagram of a polishing method based on a polishing brush which is an embodiment 4.

[0053] Figure 20 is a diagram of another example of a screw fixing mechanism.

[0054] Figure 21 is a diagram of still another example of a screw fixing mechanism.

[0055] Figure 22 is a diagram of still another example of a screw fixing mechanism. DETAILED DESCRIPTION

[0056] Hereinafter, with reference to the drawings, a polishing brush according to an embodiment of the present application will be described.

[0057] (Embodiment 1)

[0058] Figure 1 is a perspective view of a polishing brush, as viewed from the side of the abrasive bundle protrusion. Figure 2 ​is a perspective view of the abrasive brush in the case of viewing from the rear. Figure 3 is a perspective view of the abrasive brush in the case of viewing from the side opposite to the side where the abrasive bundle protrudes. Figure 4 is a rear view of the abrasive brush. Figure 5 is a sectional view of the abrasive brush after cutting along the axis of the rod-shaped member and the hole axis of the holding hole. Figure 6 is a perspective view of the brush-shaped grinding stone.

[0059] The abrasive brush 1 of this example is used for grinding processing of the inner peripheral surface of a pipe member, i.e., a workpiece, and grinding processing of the inner peripheral surface of the tubular portion of the workpiece. The workpiece is, for example, a cast product made of metal. The abrasive brush 1 is used while being attached to the head of a machine tool not shown. The head of the machine tool is, for example, the spindle head of a machining center. Further, the head of the machine tool is, for example, the tool holder of an NC turret lathe.

[0060] As shown in Figures 1 to 3 , the abrasive brush 1 has a rod-shaped member 2 and an abrasive bundle 4 composed of a plurality of wire-shaped abrasives 3. The abrasive bundle 4 is held in a holding hole 6 provided to the rod-shaped member 2. As shown in Figure 5 , the abrasive bundle 4 has a housed portion 4a housed in the holding hole 6 and a protruding portion 4b protruding from an opening 6a of the holding hole 6. The protruding portion 4b is inclined with respect to the axis L0 of the rod-shaped member 2.

[0061] Here, the end portion of the abrasive bundle 4 on the side opposite to the protruding portion 4b is held by an abrasive bundle holder 5. Thus, the abrasive bundle 4 is held in the holding hole 6 by the abrasive bundle holder 5. The abrasive bundle 4 and the abrasive bundle holder 5 constitute a brush-shaped grinding stone 20. Thus, it can be said that the rod-shaped member 2 holds the brush-shaped grinding stone 20 in the holding hole 6. The brush-shaped grinding stone 20 is detachably held in the rod-shaped member 2.

[0062] In the following description, the direction along the axis L0 of the rod-shaped member 2 will be referred to as the axis direction X. Further, one side of the axis direction X will be referred to as the front side X1, and the other side will be referred to as the rear side X2. Further, the direction orthogonal to the axis L0 will be referred to as the radial direction R. Further, the direction intersecting the axis direction X and the radial direction R, i.e., the direction in which the abrasive bundle 4 is inclined, will be referred to as the inclined direction S. Thus, the holding hole 6 is provided to the front side portion 2a of the rod-shaped member 2. The rear end portion of the rod-shaped member 2 is clamped by the head of the machine tool. In this example, the protruding portion 4b of the abrasive bundle 4 extends toward the front side X1 from the opening 6a of the holding hole 6. As shown in Figure 4 , the front end portion 4c of the protruding portion 4b is located on the outer peripheral side of the rod-shaped member 2 in the case of viewing from the axis direction X.

[0063] (Rod-shaped member)

[0064] The rod-shaped member 2 is entirely in a cylindrical shape. As shown in Figure 4As shown, the rod-shaped member 2 has a pair of flat portions 2e, 2f on both sides across the axis L0. Each of the pair of flat portions 2e, 2f extends in the axis direction X with a certain width. The rod-shaped member 2 does not have a portion that protrudes outward in the peripheral direction from the rear end surface 2c of the rod-shaped member 2 when viewed from the rear X2.

[0065] As shown, Figure 1 , Figure 2 , Figure 5 As shown, the holding hole 6 is located between the pair of flat portions 2e, 2f in the circumferential direction. As shown, Figure 5 the holding hole 6 has a bottom surface 7 and a cylindrical peripheral wall surface 8 that extends from the bottom surface 7 in the inclined direction S. The bottom surface 7 is orthogonal to the inclined direction S. The end portion of the peripheral wall surface 8 on the side opposite the bottom surface 7 is an opening 6a of the holding hole 6. The opening 6a is located at the front X1 side from the bottom surface 7. The inner diameter dimension of the peripheral wall surface 8 is constant.

[0066] The center line of the peripheral wall surface 8 is a hole axis L1 of the holding hole 6. The hole axis L1 extends in the inclined direction S. Thus, the holding hole 6 extends in the inclined direction S. Here, the inclined angle θ1 at which the hole axis L1 and the axis L0 of the rod-shaped member 2 intersect is 15° or more and 45° or less. In the present example, the inclined angle θ1 is 20°. In addition, it is preferable that the inclined angle θ1 be 20° or more and 30° or less.

[0067] Further, as shown, Figure 5 the rod-shaped member 2 has a small-diameter hole 9 that is smaller in diameter than the holding hole 6 and that extends linearly from the bottom surface 7 of the holding hole 6 to the side opposite the opening 6a. The small-diameter hole 9 penetrates the rod-shaped member 2. Thus, as shown, Figure 3 the rod-shaped member 2 has an opening 9a of the small-diameter hole 9 at the side opposite the opening 6a of the holding hole 6 across the axis L0. In the present example, the small-diameter hole 9 and the holding hole 6 are coaxial.

[0068] The front end surface 2b of the rod-shaped member 2 is a plane that intersects the axis L0. As shown, Figure 5 when the rod-shaped member 2 is viewed from an orthogonal direction V that is perpendicular to a virtual plane N that includes the hole axis L1 and the axis L0, the front end surface 2b is parallel to the hole axis L1.

[0069] The rod-shaped member 2 is provided with a recess 10 at a position X2 behind the opening 6a in the front side portion 2a of the rod-shaped member 2. The recess 10 has, when viewed from the orthogonal direction V, a front side inner wall surface 10a (inclined surface) inclined toward the direction in which the axis L0 is approached from the opening 6a side toward the rear side X2, a rear side inner wall surface 10b opposed to the front side inner wall surface 10a at the rear side X2 of the front side inner wall surface 10a and inclined toward the outer peripheral side toward the rear side X2, and a curved inner wall surface 10c connecting a rear end edge of the front side inner wall surface 10a and a front end edge of the rear side inner wall surface 10b. The front end surface 2b of the rod-shaped member 2 is parallel to the front side inner wall surface 10a.

[0070] Further, the rod-shaped member 2 is provided with a rear side opening 11a provided to the rear end surface 2c of the rod-shaped member 2, a front side opening 11b provided to the rear side inner wall surface 10b of the recess 10, and an internal flow path 11 that communicates the rear side opening 11a and the front side opening 11b. Note that the formation position of the rear side opening 11a is not limited to the rear end surface 2c. The rear side opening 11a can also be provided to a surface that faces the radial outer side at the rear end portion of the rod-shaped member 2.

[0071] Further, as shown in Figure 1 , Figure 2 , Figure 3 indicated, the rod-shaped member 2 is provided with a fixing hole 12 that communicates with the holding hole 6. The fixing hole 12 is provided to an intermediate portion between the front end surface 2b of the rod-shaped member 2 and the front side inner wall surface 10a of the recess 10 when viewed from the orthogonal direction V. The fixing hole 12 extends in a direction orthogonal to the hole axis L1 of the holding hole 6 and penetrates from the one planar portion 2e of the rod-shaped member 2 to the holding hole 6. In this example, the fixing hole 12 extends in the orthogonal direction V.

[0072] (Brush-shaped grinding stone)

[0073] As shown in Figure 6 , the abrasive beam holder 5 is provided with a cylindrical portion 21 that surrounds the end portion of the accommodation portion 4a of the abrasive beam 4 from the outer peripheral side and a bottom portion 22 that seals one opening of the cylindrical portion 21. The cylindrical portion 21 is in a cylindrical shape. The bottom portion 22 is in a disc shape. The end portion of the abrasive beam 4 abuts against the bottom portion 22. The abrasive beam 4 is fixed to the abrasive beam holder 5 by an adhesive. A screw hole 23 is provided to the bottom portion 22. The screw hole 23 penetrates the bottom portion 22. One opening 23a and the other opening 23b of the screw hole 23 are separated from each other by 180° in the circumferential direction of the bottom portion 22.

[0074] The abrasive bundle 4 is a bundle of a plurality of linear abrasives 3. The linear abrasive 3 is a linear abrasive obtained by impregnating a bundle of inorganic long fibers with a resin to harden. That is, the linear abrasive 3 has a bundle of inorganic long fibers and a resin impregnated in the bundle. As the inorganic long fibers, in addition to alumina fibers, silicon carbide fibers, boron fibers, or glass fibers can be used. In this example, the inorganic long fibers are alumina fibers. Further, as the linear abrasive 3, abrasives made of nylon, nylon with abrasive grains, rubber with abrasive grains, stainless steel, brass can be used.

[0075] The abrasive bundle 4 is bundled in a circular shape in accordance with the shape of the cylindrical portion 21 of the abrasive bundle holder 5. In this example, the front end portion 4c of the abrasive bundle 4 (the front end portion 4c of the protruding portion) has a conical shape that becomes slender toward the front end side.

[0076] (Installation of brush stone toward holding hole)

[0077] Figure 7 is a diagram illustrating a screw fixing mechanism that fixes the brush stone 20 to the rod-shaped member 2. In Figure 7 , the holding hole 6 is cut perpendicularly to the hole axis L1. As Figure 1 , Figure 2 illustrated, the brush stone 20 is held to the rod-shaped member 2 in a state where the abrasive bundle holder 5 is inserted into the holding hole 6. The brush stone 20 is fixed to the rod-shaped member 2 in a state where it cannot rotate around the hole axis L1 of the holding hole 6 by the screw fixing mechanism 25.

[0078] As Figure 7 illustrated, the screw fixing mechanism 25 has a fixing screw 15, a screw hole 23 provided to the bottom portion 22, and a fixing hole 12 provided to the rod-shaped member 2. The fixing screw 15 is cylindrical and has a male screw thread on the outer peripheral surface. The screw hole 23 penetrates the bottom portion 22 in a direction orthogonal to the hole axis L1 of the holding hole 6. The fixing hole 12 extends in a direction orthogonal to the hole axis L1 of the holding hole 6 from the one planar portion 2e of the rod-shaped member 2 to the holding hole 6. In this example, the fixing hole 12 extends in the orthogonal direction V.

[0079] The fixing screw 15 is screwed into the screw hole 23 through the fixing hole 12 to penetrate the bottom portion 22 of the abrasive bundle holder 5. Thereby, the end portion of the fixing screw 15 on the side opposite to the fixing hole 12 protrudes from the bottom portion 22. Therefore, the front end of the fixing screw 15 abuts against the peripheral wall portion 8c of the peripheral wall surface 8 on the side opposite to the fixing hole 12. Here, if the fixing screw 15 is further screwed in a state where the front end of the fixing screw 15 abuts against the peripheral wall portion 8c, a state where the abrasive bundle holder 5 is pressed against the peripheral wall portion 8d of the peripheral wall surface 8 including the opening edge of the fixing hole 12 is formed. Therefore, the brush stone 20 is fixed to the rod-shaped member 2.

[0080] In a state where the abrasive beam holder 5 is held to the holding hole 6, as shown in Figure 5 the bottom 22 abuts against the bottom face 7 of the holding hole 6. The cylindrical portion 21 contacts the peripheral wall face 8 of the holding hole 6. Here, the hole axis L1 of the holding hole 6 extends in the inclined direction S. Therefore, if the abrasive beam holder 5 is held to the holding hole 6, the abrasive beam 4 extends in the inclined direction S. Therefore, the protruding portion 4b of the abrasive beam 4 extending outward from the opening 6a at the holding hole 6 protrudes in the forward direction X1 in the inclined direction S.

[0081] Further, in a state where the brush-shaped grinding stone 20 is held to the holding hole 6, as shown in Figure 5 the end portion 4d of the abrasive beam 4 radially outward of the front end portion 4c is inclined toward the outer peripheral side in the rearward direction X2 at an angle smaller than 30° with respect to the axis L0.

[0082] Further, in a state where the brush-shaped grinding stone 20 is held to the holding hole 6, the peripheral wall face 8 of the holding hole 6 has a peripheral wall face portion 8a which opposes the accommodation portion 4a of the abrasive beam 4 from the radially inner side of the rod-shaped member 2 as compared with the hole axis L1 of the holding hole 6. In the present example, the peripheral wall face portion 8a opposes the accommodation portion 4a of the abrasive beam 4 from the front X1. An opening side region 8b of the peripheral wall face portion 8a which is a region of a prescribed width from the opening is opposed with a gap from the accommodation portion 4a.

[0083] The opening side region 8b is a region of the peripheral wall face portion 8a between the opening 6a of the holding hole 6 and the cylindrical portion 21 of the abrasive beam holder 5. In other words, the opening side region 8b is a region which opposes the portion of the accommodation portion 4a which protrudes from the abrasive beam holder 5. Here, the opening side region 8b of the peripheral wall face portion 8a is separated from the accommodation portion 4a of the abrasive beam 4 by a dimension corresponding to the thickness of the cylindrical portion 21. That is, in the present example, the inner diameter dimension of the inner peripheral wall of the holding hole 6 is constant. Further, in a state where the brush-shaped grinding stone 20 is held to the holding hole 6, the cylindrical portion 21 of the abrasive beam holder 5 contacts the peripheral wall face portion 8a of the holding hole 6 which opposes the brush-shaped grinding stone 20 from the front X1. Therefore, if the brush-shaped grinding stone 20 is held to the holding hole 6, the portion of the accommodation portion 4a of the abrasive beam 4 which protrudes from the abrasive beam holder 5 opposes the region of the peripheral wall face portion 8a from the opening 6a of the holding hole 6 to the cylindrical portion 21 of the abrasive beam holder 5 (the opening side region 8b) with a gap of an amount of dimension corresponding to the thickness of the cylindrical portion 21.

[0084] Furthermore, when retaining the brush-like grinding stone 20 in the retaining hole 6, the rod-shaped member 2 is gripped by a clamp so that the rod-shaped member 2 assumes a predetermined posture. The brush-like grinding stone 20 is then retained in the retaining hole 6 from a predetermined orientation. Specifically, the front end face 2b of the rod-shaped member 2 is parallel to the front inner wall surface 10a of the recess 10. Therefore, the area between the front end face 2b and the front inner wall surface 10a is gripped by the clamp using the front end face 2b and the front inner wall surface 10a. Thus, the rod-shaped member 2 is retained in a predetermined posture by the clamp. Consequently, the brush-like grinding stone 20 can be retained in the retaining hole 6 of the rod-shaped member 2 using an automatic machine or the like.

[0085] Furthermore, the rod-shaped member 2 includes a small-diameter hole 9 extending from the bottom surface 7 of the holding hole 6 toward the side opposite the opening 6a and penetrating the rod-shaped member 2. Therefore, when the brush-like grindstone 20 is held in the holding hole 6, air within the holding hole 6 escapes to the outside through the small-diameter hole 9. Consequently, the abrasive bundle 4 is easily retained in the holding hole 6.

[0086] In addition, if Figure 5 As shown, when the rod-shaped member 2 is viewed from the orthogonal direction V, the dimension M1 of the opening side region 8b in the direction along the hole axis L1 is greater than or equal to the diameter M2 of the abrasive bundle 4. In other words, the dimension M1 of the region within the retaining hole 6 where the abrasive bundle 4 is separated from the peripheral wall portion 8a of the retaining hole 6 is greater than or equal to the diameter M2 of the abrasive bundle 4.

[0087] (Grinding method)

[0088] Figure 8 This is an explanatory diagram of a grinding method using a grinding brush 1. In the following example, the workpiece is a long and narrow pipe member 30 (a tubular portion). The pipe member 30 has an opening 31 extending in a direction intersecting the pipe axis L midway along its material axis. Figure 8 , the pipe member 30 is shown in a cross section along the pipe axis L. Burrs are generated at the opening edge 31a of the opening 31 of the inner peripheral surface 30a of the pipe member 30. The polishing brush 1 is used for polishing to remove the burrs.

[0089] When the inner circumferential surface 30a of the pipe member 30 is polished by the polishing brush 1, the abrasive bundle 4 is inserted into the pipe member 30, with the pipe axis L of the pipe member 30 and the axis L0 of the rod-shaped member 2 aligned parallel to each other. The tip 4c of the abrasive bundle 4 is then brought into contact with the inner circumferential surface 30a. When or after the tip 4c of the abrasive bundle 4 is brought into contact with the inner circumferential surface 30a, the pipe member 30 is rotated about the pipe axis L, as indicated by arrow T1. Then, as indicated by arrow M, the polishing brush 1 is moved in the axial direction X as needed.

[0090] Further, at the time of the polishing process, air or coolant is supplied from the rear side opening 11a of the internal flow path 11 as needed. Thereby, the air or coolant is supplied toward the abrasive grain bundle 4 side through the front side opening 11b of the internal flow path 11 and the recess 10.

[0091] Here, the front end portion 4c of the abrasive grain bundle 4 protrudes outward from the rod-shaped member 2 when viewed from the axis L0 direction. Further, the rod-shaped member 2 does not have a portion that protrudes outward from the rear end surface 2c when viewed from the axis L0 direction. Therefore, if the axis L0 of the rod-shaped member 2 is made parallel with respect to the pipe axis L of the pipe member 30, the rod-shaped member 2 can be inserted deep into the pipe member 30 while avoiding interference between the rod-shaped member 2 and the opening rim 30b of the pipe member 30. Therefore, the inner peripheral surface 30a of the pipe member 30 can be polished deep with the polishing brush 1.

[0092] Further, since the abrasive grain bundle 4 is inclined with respect to the axis L0, when the front end portion 4c of the abrasive grain bundle 4 is brought into contact with the inner peripheral surface 30a of the pipe member 30 at the time of the polishing process, the abrasive grain bundle 4 is bent in a direction close to the axis L0. Therefore, the inner peripheral surface 30a of the pipe member 30 can be polished with the shape restoring force of the abrasive grain bundle 4. Further, since the abrasive grain bundle 4 is bent, it is possible to prevent or suppress the case where the abrasive grain bundle 4 excessively grinds the inner peripheral surface 30a of the pipe member 30.

[0093] Here, the inclination angle θ1 at which the hole axis L1 intersects with the axis L0 is 20°. In other words, the inclination angle θ1 at which the abrasive grain bundle 4 held in the holding hole 6 is inclined with respect to the axis L0 is 20°. In the present example, the inclination angle θ1 is 45° or less, and therefore, when the front end portion 4c of the abrasive grain bundle 4 is brought into contact with the inner peripheral surface 30a of the pipe member 30, the abrasive grain bundle 4 is easily bent toward the axis L0 side. Further, in the present example, the inclination angle θ1 is 30° or less, and therefore, the abrasive grain bundle 4 is more easily bent. Further, the inclination angle θ1 is 45° or less, and therefore, the front end portion 4c of the abrasive grain bundle 4 easily reaches deep into the pipe member 30. Further, the inclination angle θ1 is 15° or more, and therefore, the front end portion 4c of the abrasive grain bundle 4 easily comes into contact with the inner peripheral surface 30a of the pipe member 30 located on the outer peripheral side of the rod-shaped member 2.

[0094] Further, the peripheral wall surface 8 of the holding hole 6 has a peripheral wall surface portion 8a which opposes the accommodation portion 4a of the abrasive beam 4 from the radially inner side of the rod-shaped member 2 compared to the hole axis line Ll. In other words, the holding hole 6 has a peripheral wall surface portion 8a which opposes the accommodation portion 4a of the abrasive beam 4 from the front Xl. Therefore, even in the case where the abrasive beam 4 is deflected in the direction of approaching the axis line L0 under the action of the load from the inner peripheral surface 30a of the pipe member 30 to the abrasive beam 4, the deflection range of the abrasive beam 4 can be limited by the peripheral wall surface portion 8a. Therefore, the polishing power of the abrasive beam 4 to polish the inner peripheral surface 30a of the pipe member 30 can be maintained.

[0095] Here, in the case where the peripheral wall surface portion 8a of the holding hole 6 contacts the accommodation portion 4a of the abrasive beam 4, when the abrasive beam 4 is deflected under the action of the load from the inner peripheral surface 30a of the pipe member 30 to the abrasive beam 4, the abrasive beam 4 is easily broken from the portion which touches the opening edge of the holding hole 6. In this regard, in the present example, the opening side region 8b of the peripheral wall surface portion 8a which is a prescribed width from the opening opposes the accommodation portion 4a of the abrasive beam 4 with a gap. Therefore, when the abrasive beam 4 is acted upon by a load from the inner peripheral surface 30a of the pipe member 30, deflection of the abrasive beam 4 within the holding hole 6 is permitted. Thus, the case where the abrasive beam 4 is broken from the portion which touches the edge of the opening 6a of the holding hole 6 can be prevented or suppressed. Further, in the present example, the dimension Ml in the direction along the hole axis line Ll of the opening side region 8b is equal to or greater than the diameter M2 of the abrasive beam 4. Therefore, deflection of the abrasive beam 4 within the holding hole 6 is easily permitted.

[0096] Further, in the present example, the front end portion 4c of the abrasive beam 4 is a conical shape which becomes slender toward the front end side. Thus, when viewed from a direction which is perpendicular to the virtual plane N which contains the hole axis line Ll and the axis line L0, the end portion 4d on the radially outer side of the abrasive beam 4 is inclined toward the outer peripheral side rearward X2 at an angle of less than 30° with respect to the axis line L0. Therefore, when polishing the inner peripheral surface 30a of the pipe member 30, the front end portion 4c of the abrasive beam 4 can be brought into contact with the inner peripheral surface 30a in a relatively wide area from the start of polishing. Here, the front end portion 4c of the abrasive beam 4 is easily adjusted to a conical shape, and therefore, according to the present example, the manufacture of the abrasive beam 4 in which the front end is inclined is easy.

[0097] Further, the brush-shaped grindstone 20 is fixed to the rod-shaped member 2 in a state where it cannot rotate around the hole axis line Ll of the holding hole 6 by the screw fixing mechanism 25. Therefore, during polishing, the brush-shaped grindstone 20 does not rotate around the hole axis line Ll. Therefore, compared to the case where the brush-shaped grindstone 20 which is held in the holding hole 6 rotates around the hole axis line Ll within the holding hole 6, the inner peripheral surface 30a of the pipe member 30 can be polished with high precision.

[0098] (Replacement of the brush-shaped grindstone)

[0099] Next, the brush-shaped grindstone 20 is detachably attached to the rod-shaped member 2. Therefore, in the case where the abrasive beam 4 is worn due to the grinding process, the brush-shaped grindstone 20 can be replaced.

[0100] When the brush-shaped grindstone 20 is replaced, after the fixing of the fixing screw 15 is released, the pin is inserted from the opening 9a of the small-diameter hole 9. Then, the pin is caused to protrude from the bottom surface 7 of the holding hole 6 to the inside of the holding hole 6. Thereby, the abrasive beam holder 5 is pushed to the opening 6a side of the holding hole 6. Therefore, even in the case where the brush-shaped grindstone 20 is embedded in the holding hole 6, the grinding brush 1 can be caused to come off from the holding hole 6.

[0101] Here, when the abrasive beam 4 is worn, by rotating the brush-shaped grindstone 20 by 180° around the hole axis Ll, the unworn portion of the abrasive beam 4 can be caused to abut on the pipe member 30. That is, in the case where the abrasive beam 4 is worn, the fixing screw 15 is pulled out from one opening 23a of the screw hole 23 of the abrasive beam holder 5, the brush-shaped grindstone 20 is rotated by 180° around the hole axis Ll, and then the fixing screw 15 is screwed into the screw hole 23 from the other opening 23b. Thereby, the grinding brush 1 is fixed to the rod-shaped member 2 in a posture in which the unworn portion of the abrasive beam 4 faces the radially outer side. Therefore, the same brush-shaped grindstone 20 can be used to grind the inner peripheral surface 30a of the pipe member 30 again.

[0102] (Modified example of the grinding method)

[0103] Figure 9 is a diagram illustrating a modified example of the grinding method. As shown in Figure 9 , in the modified example of the grinding method, first, the axis L0 of the rod-shaped member 2 of the grinding brush 1 is set to be parallel to the pipe axis L of the pipe member 30, and the abrasive beam 4 is inserted into the pipe member 30. Then, the front end portion 4c of the abrasive beam 4 is caused to contact the inner peripheral surface 30a. Further, at the time of causing the front end portion 4c of the abrasive beam 4 to contact the inner peripheral surface 30a, or after the contact, the grinding brush 1 is caused to rotate around the pipe axis L of the rod-shaped member 2 as shown by an arrow T2. Then, as shown by an arrow M, the grinding brush 1 is moved in the axis direction X as necessary. In this way, the inner peripheral surface 30a of the pipe member 30 can also be ground in the same way as the grinding method shown in Figure 8 .

[0104] (Modified examples 1 and 2)

[0105] Figure 10 is a diagram illustrating a grinding brush of the modified example 1. Figure 11 is a diagram illustrating a grinding brush of the modified example 2. The grinding brush 1A of the modified example 1 and the grinding brush 1B of the modified example 2 differ from the above-described grinding brush 1 in the shape of the front end portion of the abrasive beam 4. However, the other configurations are the same as those of the above-described grinding brush 1. Therefore, hereinafter, the shape of the front end portion 4c of the abrasive beam 4 is described, and the other descriptions are omitted.

[0106] As Figure 10 shown in the modification example 1, the end portion 4d of the abrasive bundle 4 on the radially outer side is adjusted to be flat. When viewed from a direction perpendicular to the virtual plane N containing the hole axis L1 and the axis L0, the end portion 4d of the abrasive bundle 4 on the radially outer side is parallel to the axis L0. In this way, when the inner peripheral surface 30a of the pipe member 30 is polished, the leading end portion 4c of the abrasive bundle 4 can be brought into contact with the inner peripheral surface 30a with a relatively wide area from the start of polishing.

[0107] As Figure 11 shown in the modification example 2, the leading end surface 4e of the abrasive bundle 4 of the polishing brush 1B is adjusted to be flat perpendicular to the center line of the abrasive bundle 4. In other words, the leading end surface 4e of the abrasive bundle 4 is perpendicular to the hole axis L1 of the holding hole 6. In this example, a plurality of linear abrasives 3 of the same size can be bundled to form the abrasive bundle 4. Therefore, the manufacture of the brush-shaped grindstone 20 is easy. In this example, if the wear of the leading end portion 4c of the abrasive bundle 4 progresses due to polishing of the inner peripheral surface 30a of the pipe member 30, the leading end portion 4c of the abrasive bundle 4 can be brought into contact with the inner peripheral surface 30a with a wider area.

[0108] (Modification Example 3)

[0109] Figure 12 is a perspective view of the polishing brush of the modification example 3 as viewed from the side from which the abrasive bundle 4 protrudes. Figure 13 is a perspective view of the polishing brush of the modification example 3 as viewed from the side opposite to the side from which the abrasive bundle 4 protrudes. Figure 14 is a cross-sectional view of the polishing brush 1C of the modification example 3. The shape of the front side portion 2a of the rod-shaped member 2 of the polishing brush 1C of the modification example 3 is different from that of the above-described polishing brush 1, but the other structures are the same. Therefore, the shape of the front side portion 2a of the rod-shaped member 2 will be described, and the other descriptions will be omitted. Further, the same symbols are attached to the structures corresponding to the polishing brush 1 and described.

[0110] As Figure 12 , Figure 13 shown in the modification example 3, the rod-shaped member 2 has a cutout portion 41 at the side opposite to the opening 6a of the holding hole 6 across the axis L0. Further, as Figure 14 shown, the holding hole 6 has a second opening 42 that communicates the holding hole 6 to the outside of the rod-shaped member 2 at a part of the circumferential direction of the annular corner portion where the peripheral wall surface 8 and the bottom surface 7 intersect. More specifically, the holding hole 6 has the second opening 42 at the corner portion between the peripheral wall surface portion 8a opposite to the front X1 and the bottom surface 7 from the accommodation portion 4a of the abrasive bundle 4. As Figure 13 shown, the second opening 42 opens inside the cutout portion 41. In other words, the second opening 42 is formed in the inner peripheral surface of the cutout portion 41.

[0111] Here, the brush-shaped grindstone 20 is detachably attached to the rod-shaped member 2 by the screw fixing mechanism 25. In the brush-shaped grindstone 20 fixed to the holding hole 6, the holder corner portion 5a including a part of the circumference of the bottom portion 22 in the abrasive beam holder 5 is exposed to the outside of the rod-shaped member 2 from the second opening 42. In this example, the holder corner portion 5a is exposed to the outside from the rod-shaped member 2 on the inside of the cutout portion 41. In other words, the holder corner portion 5a does not protrude from the cutout portion 41 to the outer circumferential side of the rod-shaped member 2.

[0112] According to this example, when the brush-shaped grindstone 20 is held in the holding hole 6, air in the holding hole 6 can escape to the outside from the second opening 42. Therefore, it is easy to hold the brush-shaped grindstone 20 in the holding hole 6. Further, when the brush-shaped grindstone 20 is held in the holding hole 6, the abrasive beam holder 5 can be visually recognized through the cutout portion 41 and the second opening 42. Therefore, it is possible to visually confirm whether the brush-shaped grindstone 20 is reliably held in the holding hole 6. Further, the abrasive beam holder 5 has the holder corner portion 5a which is exposed from the rod-shaped member 2 through the cutout portion 41 and the second opening 42. Therefore, it is possible to push the holder corner portion 5a in the inclination direction S from the outside of the rod-shaped member 2. Here, if the holder corner portion 5a is pushed in the inclination direction S, the abrasive beam holder 5 moves to the opening 6a side of the holding hole 6. Therefore, it is easy to detach the brush-shaped grindstone 20.

[0113] Further, in this example, the holder corner portion 5a exposed to the outside from the rod-shaped member 2 is located on the inside of the cutout portion 41. Therefore, when the polishing brush 1C is inserted into the pipe member 30, it is possible to prevent interference between the holder corner portion 5a and the opening edge of the pipe member 30 or the like.

[0114] In addition, in this example as well, the rod-shaped member 2 can have the cutout recess portion 10. Further, the rod-shaped member 2 can have the internal flow path 11 which has the front opening 1 lb in the cutout recess portion 10. In this example as well, the same effect as the above-described polishing brush 1C can be obtained.

[0115] (Example 2)

[0116] Figure 15is an explanatory view of the abrasive brush of Example 2. The abrasive brush 50 of this example has a shape corresponding to the abrasive brush 1 described above. Therefore, the same symbols are assigned to the corresponding parts, and the description thereof is omitted. In the abrasive brush 50 of Example 2, the holding hole 6 is provided at the front end of the rod-shaped member 2. That is, the opening 6a of the holding hole 6 is provided at the front end surface 2b of the rod-shaped member 2. The holding hole 6 is recessed from the front end surface 2b toward the inclined direction S. The holding hole 6 has a bottom surface 7 and a cylindrical peripheral wall surface 8 extending from the bottom surface 7 toward the inclined direction S. The end portion of the peripheral wall surface 8 on the side opposite to the bottom surface 7 is the opening 6a. The opening 6a is formed at the front end surface 2b of the rod-shaped member 2. The opening 6a is located at a position X1 further forward than the bottom surface 7. The inner diameter dimension of the peripheral wall surface 8 is constant.

[0117] The abrasive bundle holder 5 of the brush-shaped abrasive stone 20 is held in the holding hole 6. In this example, the abrasive bundle holder 5 is fitted in the holding hole 6. Therefore, the portion of the abrasive bundle 4 held in the abrasive bundle holder 5 is accommodated in the accommodation portion 4a of the holding hole 6. Further, the portion of the abrasive bundle 4 exposed from the abrasive bundle holder 5 is a protruding portion 4b protruding forward from the front end surface 2b of the rod-shaped member 2.

[0118] In this example as well, the abrasive bundle 4 held in the holding hole 6 of the rod-shaped member 2 extends in the inclined direction S. Further, the front end portion 4c of the protruding portion 4b is located outside the rod-shaped member 2 when viewed from the axial direction X. Therefore, in the case of the inner peripheral surface 30a of the polishing pipe member 30, as long as the axis L0 of the rod-shaped member 2 is made parallel to the pipe axis L of the pipe member 30 to insert the abrasive bundle 4 into the pipe member 30, the front end portion 4c of the abrasive bundle 4 can be brought into contact with the inner peripheral surface 30a. Thus, the inner peripheral surface 30a of the pipe member 30 can be polished by the abrasive brush 50 of this example. Further, the holding hole 6 of the rod-shaped member 2 holding the abrasive bundle 4 is recessed in the inclined direction S. Therefore, as long as the brush-shaped abrasive stone 20 is held in the holding hole 6, the abrasive bundle 4 can be made to protrude from the opening 6a of the holding hole 6 toward the inclined direction S.

[0119] (Example 3)

[0120] Figure 16 is an explanatory view of the abrasive brush of Example 2. In the abrasive brush 51 of this example, the abrasive bundle 4 is directly held in the holding hole 6 of the rod-shaped member 2. In addition, the abrasive brush 51 of Example 3 has a structure corresponding to the abrasive brush 1, and therefore, the same symbols are assigned to the corresponding parts, and the description thereof is omitted.

[0121] As Figure 16As shown, the abrasive brush 51 is provided with the rod-shaped member 2 and the abrasive bundle 4 composed of a plurality of linear abrasives 3. The abrasive bundle 4 is held in the holding hole 6 provided to the rod-shaped member 2. The abrasive bundle 4 is provided with the housed portion 4a housed in the holding hole 6 and the protruding portion 4b protruding from the opening 6a of the holding hole 6. The protruding portion 4b is inclined with respect to the axis L0 of the rod-shaped member 2.

[0122] The holding hole 6 is provided with the large-diameter hole portion 55 from the opening 6a side toward the bottom surface 7 and the small-diameter hole portion 56 coaxial with the large-diameter hole portion 55 and having a smaller inner diameter than the large-diameter hole portion 55. The end portion of the abrasive bundle 4 on the side opposite the protruding portion 4b of the housed portion 4a is inserted into the small-diameter hole portion 56. Further, the end portion of the abrasive bundle 4 on the side opposite the protruding portion 4b of the housed portion 4a is fixed to the small-diameter hole portion 56 by an adhesive or the like.

[0123] In this example as well, the peripheral wall surface 8 of the holding hole 6 is provided with the peripheral wall surface portion 8a which opposes the housed portion 4a of the abrasive bundle 4 from the radially inner side of the rod-shaped member 2 than the hole axis L1. In other words, the holding hole 6 is provided with the peripheral wall surface portion 8a which opposes the housed portion 4a of the abrasive bundle 4 from the front X1. Further, the opening side region 8b of the peripheral wall surface portion 8a of a prescribed width from the opening 6a opposes the housed portion 4a with a gap. In this example, the opening side region 8b is the inner peripheral surface of the large-diameter hole portion 55 and is a region which opposes the housed portion 4a of the abrasive bundle 4 from the front X1.

[0124] In this example, the abrasive bundle 4 is directly fixed to the rod-shaped member 2, and thus, when the abrasive bundle 4 is worn, it is not easy to replace the new abrasive bundle 4. However, except for this point, the abrasive brush 51 of this example is able to obtain the same functional effects as the above-described abrasive brush 1. Here, the abrasive brush 51 of this example is not provided with the abrasive bundle holder 5. Thus, correspondingly, it is possible to suppress the manufacturing cost of the abrasive brush 51.

[0125] (Embodiment 4)

[0126] Figure 17 is a perspective view of the abrasive brush of Embodiment 4 as viewed from the abrasive bundle 4 side. Figure 18 is a cross-sectional view of the abrasive brush of Embodiment 4. In the abrasive brush 60 of the modified example 4, the protruding portion 4b of the abrasive bundle 4 extends toward the rear X2. Further, the abrasive brush 60 of Embodiment 4 is provided with the structure corresponding to the above-described abrasive brush 1, and thus, the same symbols are marked for the corresponding portions, and the explanation thereof is omitted.

[0127] As Figure 17As shown, the abrasive brush 60 of this embodiment includes a rod-shaped member 2 and an abrasive bundle 4 composed of multiple linear abrasives 3. The abrasive bundle 4 is held in a holding hole 6 provided in the front portion 2a of the rod-shaped member 2. The abrasive bundle 4 includes a receiving portion 4a received in the holding hole 6 and a protruding portion 4b protruding from the opening 6a of the holding hole 6. The abrasive bundle 4 extends in an inclined direction S that intersects the axial direction X and the radial direction R. In this embodiment, the protruding portion 4b is inclined from the opening 6a of the holding hole 6 toward the outer periphery and rearward in a direction X2. When viewed from the axial direction X, the front end 4c of the protruding portion 4b is located outside the rod-shaped member 2.

[0128] like Figure 18 As shown, the end of the receiving portion 4a opposite the protruding portion 4b is held by an abrasive bundle holder 5. The abrasive bundle 4 is removably held in the holding hole 6 by the abrasive bundle holder 5. The abrasive bundle 4 and the abrasive bundle holder 5 constitute a brush-like grindstone 20. Therefore, the rod-like member 2 removably holds the brush-like grindstone 20 in the holding hole 6. The brush-like grindstone 20 is the same as the brush-like grindstone 20 of the aforementioned grinding brush 1.

[0129] Here, the retaining hole 6 provided in the rod-shaped member 2 includes a bottom surface 7 and a cylindrical peripheral wall surface 8 extending from the bottom surface 7 in an inclined direction S. Therefore, the retaining hole 6 extends in the inclined direction S. The bottom surface 7 is perpendicular to the inclined direction S. The end of the peripheral wall surface 8 opposite the bottom surface 7 is the opening 6a of the retaining hole 6. In this example, the opening 6a of the retaining hole 6 is located at a position X2 behind the bottom surface 7. The inner diameter of the peripheral wall surface 8 is constant. Here, the hole axis L1 extends in the inclined direction S. The inclination angle θ1 formed by the intersection of the hole axis L1 and the axis L0 of the rod-shaped member 2 is greater than 15° and less than 45°. In this example, the inclination angle θ1 is 20°.

[0130] like Figure 17 As shown, the front end face 2b of the rod-shaped member 2 is a plane perpendicular to the axis L0. The rod-shaped member 2 includes a fixing hole 12 between the front end face 2b and the opening 6a in the axial direction X, which is connected to the retaining hole 6. The fixing hole 12 extends in a direction perpendicular to the hole axis L1 of the retaining hole 6. In this example, the fixing hole 12 extends in a perpendicular direction V perpendicular to a virtual plane N including the axis L0 and the hole axis L1.

[0131] Here, if Figure 18 As shown, the holding hole 6 has a second opening 42 at a portion of the circumference of the annular corner where the peripheral wall surface 8 and the bottom surface 7 intersect, thereby connecting the holding hole 6 to the outside of the rod-shaped member 2. In this example, the holding hole 6 has the second opening 42 at the corner between the portion of the peripheral wall surface 8 located closer to the opening 6a than the axis L0 of the rod-shaped member and the bottom surface 7. Figure 17 As shown, the second opening 42 opens at the front end surface 2 b of the rod-shaped member 2 .

[0132] (Install the brush-like grinding stone toward the retaining hole)

[0133] like Figure 18 As shown, the brush-like grindstone 20 is held by the rod-like member 2 with the abrasive bundle holder 5 inserted into the holding hole 6. The brush-like grindstone 20 is fixed to the rod-like member 2 by a screw fixing mechanism 25 so that it cannot rotate about the hole axis L1 of the holding hole 6. Specifically, the fixing screw 15 of the screw fixing mechanism 25 is screwed into the screw hole 23 of the abrasive bundle holder 5 through the fixing hole 12 of the rod-like member 2. The fixing screw 15 is cylindrical and has a male thread on its outer circumference.

[0134] When the abrasive bundle holder 5 is held in the holding hole 6, the bottom portion 22 abuts against the bottom surface 7 of the holding hole 6. Furthermore, the cylindrical portion 21 contacts the peripheral wall surface 8 of the holding hole 6. Here, the hole axis L1 of the holding hole 6 extends in the inclined direction S. Therefore, when the abrasive bundle holder 5 is held in the holding hole 6, the abrasive bundle 4 extends in the inclined direction S. Consequently, the protruding portion 4b extending outward from the opening 6a in the holding hole 6 protrudes rearwardly X2 in the inclined direction S.

[0135] With the brush-like grindstone 20 held in the holding hole 6 , the radially outer end of the front end portion 4 c of the abrasive bundle 4 is inclined forward X1 toward the outer circumference at an angle smaller than 30° relative to the axis L0 .

[0136] Furthermore, when the brush-like grinding stone 20 is held in the holding hole 6, the peripheral wall surface 8 of the holding hole 6 includes a peripheral wall surface portion 8a that faces the housing portion 4a of the abrasive bundle 4 from the radially inner side of the rod-shaped member 2 relative to the hole axis L1 of the holding hole 6. In this example, the peripheral wall surface portion 8a faces the housing portion 4a of the abrasive bundle 4 from the rear X2. An opening-side region 8b of the peripheral wall surface portion 8a, having a predetermined width from the opening, faces the housing portion 4a with a gap therebetween.

[0137] The opening-side region 8b is a region of the peripheral wall surface portion 8a between the opening 6a of the holding hole 6 and the cylindrical portion 21 of the abrasive beam holder 5. In other words, the opening-side region 8b is a region opposite to the portion of the accommodation portion 4a exposed from the abrasive beam holder 5. Here, the opening-side region 8b of the peripheral wall surface portion 8a is separated from the accommodation portion 4a of the abrasive beam 4 by a dimension corresponding to the thickness of the cylindrical portion 21. That is, in the present example, the inner diameter dimension of the inner peripheral wall of the holding hole 6 is constant. Further, in a state where the brush-shaped grinding stone 20 is held to the holding hole 6, the cylindrical portion 21 of the abrasive beam holder 5 is in contact with the peripheral wall surface portion 8a of the holding hole 6 opposite to the brush-shaped grinding stone 20 from the rear X2. Therefore, if the brush-shaped grinding stone 20 is held to the holding hole 6, the portion of the accommodation portion 4a of the abrasive beam 4 exposed from the abrasive beam holder 5 is opposed to the region of the peripheral wall surface portion 8a of the holding hole 6 from the opening 6a to the cylindrical portion 21 of the abrasive beam holder 5 (the opening-side region 8b) with a gap of an amount corresponding to the dimension of the thickness of the cylindrical portion 21.

[0138] Further, in a state where the brush-shaped grinding stone 20 is held to the holding hole 6, the holder corner portion 5a including a portion of the peripheral direction of the bottom portion 22 of the abrasive beam holder 5 is exposed to the outside of the rod-shaped member 2 from the second opening 42. In the present example, the holder corner portion 5a protrudes from the rod-shaped member 2 to the front X1. Therefore, in a case where the polishing brush 60 is observed from the axial direction X, the holder corner portion 5a does not protrude from the rod-shaped member 2 to the outer peripheral side.

[0139] (Polishing method)

[0140] Figure 19 is a diagram illustrating a polishing method of the polishing brush 60 of Example 4. Even in a case where the polishing brush 60 of the present example is used, the inner peripheral surface 30a of the pipe member 30 can be polished by the polishing method illustrated in Figure 8 , Figure 9 Further, in a case where the polishing brush 60 of the present example is used, as illustrated in Figure 19 , the step portion 32 provided to the inner peripheral surface 30a of the pipe member 30 can be polished from the deep side of the pipe member 30.

[0141] That is, in a case where the step portion 32 is provided to the inner peripheral surface 30a of the pipe member 30, as illustrated in Figure 19As shown, the axis L0 of the rod-shaped member 2 is set to be parallel with respect to the pipe axis L of the pipe member 30, and the abrasive brush 60 is inserted into the pipe member 30 until the abrasive bundle 4 is located at a position deeper than the step portion 32. Then, the leading end portion 4c of the abrasive bundle 4 is caused to contact the step portion 32 from the deep side of the pipe member 30. Further, at the time when the leading end portion 4c of the abrasive bundle 4 contacts the inner peripheral surface 30a, or after the contact, the pipe member 30 is caused to rotate around the pipe axis L as shown by an arrow T1. Further, as needed, the abrasive brush 60 is caused to move in the axis direction X as shown by an arrow M. In addition, at the time when the leading end portion 4c of the abrasive bundle 4 contacts the inner peripheral surface 30a, or after the contact, the abrasive brush 60 is caused to rotate around the axis L0 of the rod-shaped member 2 as shown by an arrow T2, or the abrasive brush 60 is caused to move in the axis direction X as shown by an arrow M. Figure 9 As shown, the abrasive brush 60 is caused to rotate around the axis L0 of the rod-shaped member 2, and as needed, the abrasive brush 60 is caused to move in the axis direction X.

[0142] (EFFECTS)

[0143] In the present example as well, the leading end portion 4c of the abrasive bundle 4 protrudes outward from the rod-shaped member 2 when viewed from the axis L0 direction. Further, the rod-shaped member 2 does not have a portion that protrudes outward from the rear end surface 2c to the outer peripheral side when viewed from the axis L0 direction. Therefore, if the axis L0 of the rod-shaped member 2 is set to be parallel with respect to the pipe axis L of the pipe member 30, it is possible to insert the rod-shaped member 2 into the deep portion of the pipe member 30 while avoiding interference between the rod-shaped member 2 and the opening edge 30b of the pipe member 30. Therefore, it is possible to grind the inner peripheral surface 30a of the pipe member 30 with the abrasive brush 60 until the deep portion.

[0144] Further, in the present example, the abrasive bundle 4 is inclined with respect to the axis L0, and therefore, when the leading end portion 4c of the abrasive bundle 4 is caused to contact the inner peripheral surface 30a of the pipe member 30 at the time of grinding processing, the abrasive bundle 4 is caused to flex in the direction close to the axis L0. Therefore, it is possible to grind the inner peripheral surface 30a of the pipe member 30 with the shape restoring force of the abrasive bundle 4. Further, since the abrasive bundle 4 is caused to flex, it is possible to prevent or suppress the case where the abrasive bundle 4 excessively grinds the inner peripheral surface 30a of the pipe member 30. In this regard, the inclination angle θ1 in the present example is 45° or less. Therefore, when the leading end portion 4c of the abrasive bundle 4 is caused to contact the inner peripheral surface 30a of the pipe member 30, it is easy to cause the abrasive bundle 4 to flex.

[0145] Further, the peripheral wall surface 8 of the holding hole 6 has a peripheral wall surface portion 8a which opposes the accommodation portion 4a of the abrasive grain bundle 4 from the radially inner side of the rod-shaped member 2 compared to the hole axis Ll of the holding hole 6. In other words, the holding hole 6 has a peripheral wall surface portion 8a which opposes the accommodation portion 4a of the abrasive grain bundle 4 from the rear X2. Therefore, even in the case where the abrasive grain bundle 4 is deflected in the direction close to the axis L0 under the load applied to the abrasive grain bundle 4 from the inner peripheral surface 30a of the pipe member 30, the deflection range of the abrasive grain bundle 4 can be limited by the peripheral wall surface portion 8a. Therefore, the polishing power of the abrasive grain bundle 4 to polish the inner peripheral surface 30a of the pipe member 30 can be maintained.

[0146] Further, in the present example, an opening side region 8b of the peripheral wall surface portion 8a which is a region of a prescribed width from the opening opposes the accommodation portion 4a with a gap. Therefore, when the load is applied to the abrasive grain bundle 4 by the inner peripheral surface 30a of the pipe member 30, the abrasive grain bundle 4 is allowed to be deflected within the holding hole 6. Thereby, the case where the abrasive grain bundle 4 is broken from the portion which abuts against the opening edge of the holding hole 6 can be prevented or suppressed.

[0147] Further, in the present example, a second opening 42 which communicates with the holding hole 6 is provided at the front end surface 2b of the rod-shaped member 2. Therefore, when the brush-shaped abrasive stone 20 is held in the holding hole 6, the air within the holding hole 6 can escape to the outside from the second opening 42. Therefore, it is easy to hold the brush-shaped abrasive stone 20 in the holding hole 6. Further, when the brush-shaped abrasive stone 20 is held in the holding hole 6, the abrasive grain bundle holder 5 can be visually confirmed through the cutout portion 41 and the second opening 42. Therefore, it is possible to confirm whether the brush-shaped abrasive stone 20 is reliably held in the holding hole 6 by visual confirmation. Further, the abrasive grain bundle holder 5 has a holder corner portion 5a which is exposed from the rod-shaped member 2 through the second opening 42. Therefore, the holder corner portion 5a can be pushed in the tilting direction S from the outside of the rod-shaped member 2. Here, if the holder corner portion 5a is pushed in the tilting direction S, the abrasive grain bundle holder 5 moves to the opening 6a side of the holding hole 6. Therefore, it is easy to detach the brush-shaped abrasive stone 20.

[0148] Here, in the present example, the holder corner portion 5a which is exposed to the outside from the rod-shaped member 2 protrudes from the front end surface 2d of the rod-shaped member in the front direction Xl. Therefore, when the polishing brush 51 is inserted into the pipe member 30, the holder corner portion 5a can be prevented from being interfered with the opening edge or the like of the pipe member 30.

[0149] Further, in the present example as well, the brush-shaped abrasive stone 20 is detachably attached to the rod-shaped member 2 by the screw fixing mechanism 25. Therefore, during polishing, the brush-shaped abrasive stone 20 does not rotate around the hole axis Ll. Therefore, compared to the case where the brush-shaped abrasive stone 20 held in the holding hole 6 rotates around the hole axis Ll within the holding hole 6, the inner peripheral surface 30a of the pipe member 30 can be polished with high accuracy.

[0150] Further, in a case where the abrasive beam 4 is worn out due to grinding, the brush-shaped grinding stone 20 can be replaced. Further, at the outer peripheral surface of the bottom 22 of the abrasive beam holder 5, one-side opening 23a and other-side opening 23b of a screw hole 23 are provided at positions separated 180° from each other in the circumferential direction. Therefore, when the abrasive beam 4 is worn out, by rotating the brush-shaped grinding stone 20 by 180° around the hole axis line LI to be installed again in the holding hole 6, it is possible to make the part of the abrasive beam 4 which is not worn out abut against the inner peripheral surface 30a of the pipe member 30.

[0151] Further, in the present example as well, the cutout recess 10 can be provided in the front side portion 2a of the rod-shaped member 2 at the rear X2 of the opening 61 of the holding hole 6. Further, in this case, the rod-shaped member 2 can be provided with the internal flow path 11 which is provided with the front side opening lib at the cutout recess 10. In this way, it is possible to supply air or coolant to the side of the abrasive beam 4 through the internal flow path 11.

[0152] Further, the holding hole 6 can be provided with the second opening 42 which communicates with the outside of the rod-shaped member 2 through the cutout portion 41 at the corner between the peripheral wall surface portion 8a which opposes the housing portion 4a of the abrasive beam 4 from the rear X2 and the bottom surface 7. In this case, as with the grinding brush 1C of the modified example 3, the rod-shaped member 2 is provided with the cutout portion 41 on the side opposite to the opening 6a of the holding hole 6 across the axis line LO. Further, the second opening 42 is opened inside the cutout portion 41. In this way, when the brush-shaped grinding stone 20 is held in the holding hole 6, the holder corner portion 5a of the abrasive beam holder 5 which includes a part of the circumference of the bottom 22 is exposed to the outside from the rod-shaped member 2 inside the cutout portion 41.

[0153] (Another example of screw fixing mechanism)

[0154] Figure 20 is a diagram illustrating another example of a screw fixing mechanism. Figure 21 and Figure 22 is a diagram illustrating still another example of a screw fixing mechanism. In Figure 20 , the holding hole 6 is cut perpendicularly to the hole axis line LI. In Figure 21 , the periphery of the holding hole 6 is cut along the axis line LO of the rod-shaped member 2 and the hole axis line LI of the holding hole 6. In Figure 22 , the holding hole 6 is cut obliquely with respect to the hole axis line LI.

[0155] Figure 20 the screw fixing mechanism 25A illustrated in Figure 21 and Figure 22 the screw fixing mechanism 25B illustrated in can be used instead of the above-described screw fixing mechanism 25 when fixing the brush-shaped grinding stone 20 in the holding hole 6 of the rod-shaped member 2.

[0156] As Figure 20As shown, the screw fixing mechanism 25A includes a fixing screw 15, a screw hole 23 provided in the base 22, and a fixing hole 12 provided in the rod-shaped member 2. The fixing screw 15 includes a shaft portion 15a having a male thread on its outer circumference that is threadably engaged with the screw hole 23, and a head portion 15b provided at one end of the shaft portion 15a. The outer diameter of the head portion 15b is larger than that of the shaft portion 15a. The screw hole 23 extends through the base 22 in a direction perpendicular to the hole axis L1 of the retaining hole 6. The fixing hole 12 extends in a direction perpendicular to the hole axis L1 of the retaining hole 6, extending from a flat portion 2e on one side of the rod-shaped member 2 to the retaining hole 6. In this example, the fixing hole 12 includes a small-diameter portion 12a having a larger diameter than the shaft portion 15a and a smaller diameter than the head portion 15b, and a large-diameter portion 12b located on the outer circumference of the small-diameter portion 12a and having a larger inner diameter than that of the small-diameter portion 12a. Furthermore, the fixing hole 12 includes an annular surface 12 c between the small-diameter portion 12 a and the large-diameter portion 12 b .

[0157] The shaft portion 15a of the fixing screw 15 is screwed into the screw hole 23 through the fixing hole 12. The head portion 15b is accommodated in the large-diameter portion 12b. The head portion 15b abuts against the annular surface 12c of the rod-shaped member 2 from the outer circumference. As a result, the brush-like grindstone 20 is fixed to the rod-shaped member 2, with the abrasive bundle holder 5 pressed against the peripheral wall portion 8d of the peripheral wall surface 8, which includes the opening edge of the fixing hole 12.

[0158] Even when the screw fixing mechanism 25A of this embodiment is used, the brush-like grinding stone 20 is fixed to the rod-like member 2 in a state in which it cannot rotate about the hole axis L1. Furthermore, when the abrasive bundle 4 wears, the brush-like grinding stone 20 can be rotated 180° about the hole axis L1 and retained in the retaining hole 6 again. This allows the brush-like grinding stone 20 to be reused.

[0159] Then, if Figure 21 、 Figure 22 As shown, screw fixing mechanism 25B includes a fixing screw 15 and a screw hole 27 provided in rod-shaped member 2. Fixing screw 15 is axially shaped, and has a male thread on its outer circumference that is threadably engaged with screw hole 27. Screw hole 27 extends in a perpendicular direction V, which is perpendicular to the hole axis L1 of retaining hole 6. Furthermore, screw hole 27 includes a connecting portion 27a, which communicates with retaining hole 6, at a portion of its circumference. Connecting portion 27a is located midway along screw hole 27 in perpendicular direction V.

[0160] Here, the fixing screw 15 has a protruding portion 15c that, when screwed into the screw hole 27, protrudes from the connecting portion 27a into the retaining hole 6. The protruding portion 15c contacts the abrasive bundle holder 5 from the opening 6a of the retaining hole 6. In other words, the protruding portion 15c contacts the front end of the cylindrical portion 21 from the opening 6a of the retaining hole 6. As a result, the brush-like grindstone 20 is fixed to the rod-shaped member 2 in a state in which it cannot rotate about the hole axis L1 of the retaining hole 6.

[0161] In the case of the screw fixing mechanism 25B of this example as well, the brush-shaped grindstone 20 is fixed to the rod-shaped member 2 in a state in which it cannot rotate around the hole axis line L1. Furthermore, when the abrasive beam 4 is worn, the brush-shaped grindstone 20 can be rotated by a desired angle around the hole axis line L1 and be held again in the holding hole 6. Thereby, the brush-shaped grindstone 20 can be used again.

Claims

1. A polishing brush characterized by, Having: an abrasive bundle composed of a plurality of linear abrasives; and a rod-shaped member, when a direction along an axis of the rod-shaped member is set as an axial direction, a direction orthogonal to the axis is set as a radial direction, a direction intersecting the axial direction and the radial direction is set as an oblique direction, one of the axial direction is set as a front direction, and the other is set as a rear direction, the rod-shaped member has a holding hole that holds the abrasive bundle at a front side portion thereof, the holding hole has a bottom surface, a cylindrical peripheral wall surface that extends from the bottom surface to the oblique direction, and an opening toward one direction of the radial direction, the abrasive bundle has a housed portion that is housed in the holding hole and a protruding portion that protrudes from the opening of the holding hole to the oblique direction, an oblique angle at which a hole axis of the holding hole intersects the axis is 45° or less, a front end portion of the protruding portion is located outside the rod-shaped member when viewed from the axial direction.

2. The abrasive brush according to claim 1, wherein the abrasive bundle is one.

3. The abrasive brush according to claim 1 or 2, wherein the peripheral wall surface of the holding hole has a peripheral wall surface portion that opposes the housed portion from an inner side of the radial direction compared to the hole axis of the holding hole.

4. The abrasive brush according to claim 3, wherein an opening side region of the peripheral wall surface portion that is a prescribed width from the opening opposes the housed portion with a gap.

5. The abrasive brush according to claim 4, having an abrasive bundle holder that holds an end portion of the housed portion on a side opposite the protruding portion, the abrasive bundle is detachably held in the holding hole by the abrasive bundle holder.

6. The abrasive brush according to claim 5, wherein the abrasive bundle holder has a cylindrical portion that surrounds the end portion of the housed portion on a side opposite the protruding portion from an outer peripheral side, and a bottom portion that seals an opening of one side of the cylindrical portion, the bottom portion abuts against the bottom surface, the cylindrical portion contacts a portion of the peripheral wall surface portion that is on a side closer to the bottom surface than the opening side region.

7. The abrasive brush according to claim 6, having a screw fixing mechanism that fixes the abrasive bundle holder to the rod-shaped member in a state in which the abrasive bundle holder cannot rotate around the hole axis of the holding hole.

8. The abrasive brush according to claim 7, wherein the cylindrical portion is a circular cylindrical shape, the bottom portion is a circular disc shape, the screw fixing mechanism has a fixing screw, a screw hole that penetrates the bottom portion in a direction orthogonal to the hole axis of the holding hole, and a fixing hole that extends in the rod-shaped member in a direction orthogonal to the hole axis of the holding hole and penetrates from an outer side of the rod-shaped member to the holding hole, the fixing screw penetrates the bottom portion by being screwed into the screw hole through the fixing hole, thereby abutting against the peripheral wall surface.

9. The abrasive brush according to claim 7, wherein the cylindrical portion is a circular cylindrical shape, the bottom portion is a circular disc shape, ​ ​ The screw fixing mechanism includes a fixing screw, a screw hole that penetrates the bottom in a direction orthogonal to a hole axis of the holding hole, and a fixing hole that extends in the rod-shaped member in a direction orthogonal to the hole axis of the holding hole and penetrates the holding hole from the outside of the rod-shaped member, The fixing screw includes a shaft portion that includes a male screw thread that can be screwed into the screw hole on an outer peripheral surface, and a head portion that is provided at an end portion of one side of the shaft portion, The shaft portion is screwed into the screw hole through the fixing hole, The head portion abuts against the rod-shaped member from the outer peripheral side.

10. The abrasive brush according to claim 7, wherein The cylindrical portion is cylindrical in shape, The screw fixing mechanism includes a fixing screw, and a screw hole that extends in the rod-shaped member in a direction orthogonal to a hole axis of the holding hole, The screw hole includes a communication portion that communicates with the holding hole at a portion of a circumference of the screw hole, The fixing screw includes a protruding portion of the fixing screw that protrudes into the holding hole from the communication portion when screwed into the screw hole, The protruding portion of the fixing screw abuts against the cylindrical portion from an opening side of the holding hole in the inclined direction.

11. The abrasive brush according to any one of claims 6 to 10, wherein The rod-shaped member includes a small-diameter hole that has an inner diameter smaller than an inner diameter of the holding hole and that extends linearly from the bottom surface to the side opposite the opening of the holding hole and penetrates the rod-shaped member.

12. The abrasive brush according to any one of claims 6 to 10, wherein The holding hole includes a second opening that communicates the holding hole with the outside of the rod-shaped member at a portion of a circumference of a ring-shaped corner portion where the peripheral wall surface intersects the bottom surface, A holder corner portion of the abrasive grain bundle holder, including a portion of a circumference of the bottom portion, is exposed to the outside from the rod-shaped member through the second opening.

13. The abrasive brush according to claim 12, wherein The rod-shaped member includes a cutout portion on the side opposite the opening of the holding hole across the axis when viewed in an orthogonal direction perpendicular to an imaginary plane that includes the axis and a hole axis of the holding hole, The second opening is open on the inside of the cutout portion, The holder corner portion is located on the inside of the cutout portion.

14. The abrasive brush according to any one of claims 1, 2, 4 to 10, and 13, wherein The rod-shaped member includes a front-side opening provided on the rear side of the opening of the front-side portion of the rod-shaped member, a rear-side opening provided on a rear end portion of the rod-shaped member, and an internal flow path that communicates the front-side opening with the rear-side opening.

15. The abrasive brush according to any one of claims 1, 2, 4 to 10, and 13, wherein The protruding portion protrudes toward the front from the opening of the holding hole.

16. The abrasive brush according to claim 15, wherein ​ The rod-shaped member has a recess located behind the opening at a front side portion of the rod-shaped member when viewed from a normal direction perpendicular to a virtual plane including a hole axis of the holding hole and the axis, a front end surface of the rod-shaped member is parallel to the hole axis when viewed from the normal direction, the recess has an inclined surface inclined from the opening side toward the rear side to the side where the axis is located when viewed from the normal direction, the front end surface is parallel to the inclined surface.

17. The abrasive brush according to any one of claims 1, 2, 4 to 10, and 13, wherein the protruding portion protrudes from the opening of the holding hole toward the rear side.

18. The abrasive brush according to any one of claims 1, 2, 4 to 10, 13, and 16, wherein an end portion of an outer side of the abrasive beam is parallel to the axis when viewed from a normal direction perpendicular to a virtual plane including a hole axis of the holding hole and the axis.

19. The abrasive brush according to any one of claims 1, 2, 4 to 10, 13, and 16, wherein a front end portion of the protruding portion has a conical shape that becomes slender toward a front end side in the inclined direction.

20. The abrasive brush according to any one of claims 1, 2, 4 to 10, 13, and 16, wherein an inclined angle at which the hole axis of the holding hole and the axis intersect is 15° or more.

21. An abrasive method of polishing an inner peripheral surface of a tubular portion of a workpiece using the abrasive brush according to any one of claims 1 to 20, wherein the axis of the rod-shaped member is made parallel to a pipe axis of the tubular portion, and the abrasive beam is inserted into the tubular portion, the workpiece is rotated around the pipe axis in a state where the abrasive beam contacts the inner peripheral surface.

22. An abrasive method of polishing an inner peripheral surface of a tubular portion of a workpiece using the abrasive brush according to any one of claims 1 to 20, wherein the axis of the rod-shaped member is made parallel to a pipe axis of the tubular portion, and the abrasive beam is inserted into the tubular portion, the abrasive brush is rotated around the axis in a state where the abrasive beam contacts the inner peripheral surface.

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