CN114007811A

CN114007811A - Inner surface grinding device for metal pipe and metal pipe

Info

Publication number: CN114007811A
Application number: CN202080046512.5A
Authority: CN
Inventors: 福本泰治; 中岛实; 川口忠士
Original assignee: Osaka Health Co ltd
Current assignee: Osaka Health Co ltd
Priority date: 2019-06-25
Filing date: 2020-06-25
Publication date: 2022-02-01
Anticipated expiration: 2040-06-25
Also published as: JP6663067B1; JP2021003748A; EP3991914A1; EP3991914A4; CN114007811B; WO2020262562A1

Abstract

The jig (21) is provided with a brush (44) and a tube (46), wherein the brush (44) protrudes in a radial direction perpendicular to the shaft (23) and has elasticity, and the tube (46) is arranged at a position closer to the inner side of the brush (44) in the radial direction. The dimension between the shaft (23) and the front end of the brush (44) is more than half of the inner diameter of the stainless steel pipe (1). When the jig (21) is disposed inside the stainless steel pipe (1), the pipe (46) presses the brush (44) radially outward, and the tip of the brush (44) abuts against the inner surface of the stainless steel pipe (1) in an upright state, thereby applying internal pressure. Thereby, the abrasive supplied from the pump (12) adheres to the inner surface of the stainless steel pipe (1). The polishing agent attached to the inner surface of the stainless steel pipe (1) is pressed against the inner surface of the stainless steel pipe (1) by a brush (44).

Description

Inner surface grinding device for metal pipe and metal pipe

Technical Field

The present invention relates to an inner surface grinding apparatus for a metal pipe and a metal pipe having an inner surface ground by using the same.

Background

Conventionally, when an inner surface of a metal pipe is polished, a method of performing a base treatment using an abrasive having a small particle size number and then finish-polishing the inner surface using an abrasive having a large particle size number is known. Such a polishing method is adopted in so-called vertical polishing (see patent document 1), in which the inner surface of a metal pipe is polished by pressing a polishing tape against the inner surface of the metal pipe and moving the polishing tape in the longitudinal direction of the metal pipe.

Documents of the prior art

Patent document

Patent document 1: japanese laid-open patent publication No. 11-188594

Disclosure of Invention

Technical problem to be solved by the invention

However, the longitudinal polishing described in patent document 1 has a problem that the inner surface of the metal pipe after polishing has a rough surface. Therefore, it is not preferable for a tube used in, for example, a manufacturing apparatus of a medicine or a food, and a metal tube of an inner surface having a smaller surface roughness is desired.

In addition, the longitudinal polishing described in patent document 1 has problems that: dust generated when the inner surface of the metal pipe is ground is scattered into the atmosphere, or the grinding time is increased in order to replace a worn grinding belt with a new one.

The present invention has been made to solve the above-described problems, and an object thereof is to provide a metal tube inner surface polishing apparatus capable of forming a metal tube whose inner surface is mirror-finished, and a metal tube whose inner surface is polished by using the same.

It is another object of the present invention to provide an apparatus for polishing an inner surface of a metal pipe, which can prevent dust generated during polishing from scattering into the atmosphere and can shorten a polishing time as compared with conventional longitudinal polishing, and a metal pipe whose inner surface is polished by using the apparatus.

Means for solving the problems

An apparatus for polishing an inner surface of a metal pipe as a material to be polished according to the present invention is an apparatus for polishing an inner surface of a metal pipe, comprising: a rotating body extending in an axial direction; a driving unit that rotates the rotating body about the shaft; and a supply unit that supplies a polishing liquid in which a granular polishing agent and a liquid are mixed to the inside of the metal tube, wherein the rotating body has a brush that protrudes in a radial direction orthogonal to the shaft and has elasticity, and an inner elastic body that is disposed at a position radially inward of the brush, a dimension between the shaft and a tip of the brush being at least half an inner diameter of the metal tube, and the inner elastic body presses the brush radially outward in a state in which the rotating body is disposed inside the metal tube, whereby a tip of the brush abuts against an inner surface of the metal tube in an upright state, and internal pressure is applied to the inner surface of the metal tube, whereby the polishing agent supplied from the supply unit to the inner surface of the metal tube adheres to the inner surface of the metal tube, and the inner surface of the metal tube is pressed by the tip of the brush, thereby abrading the inner surface.

In the present invention, the "metal pipe" refers to a metal pipe, a metal cylindrical member, or a metal pipe. In the present invention, the "metal pipe inner surface polishing device" refers to a "metal pipe inner surface polishing device", a "metal tubular member inner surface polishing device", or a "metal pipe inner surface polishing device".

In the present invention, the phrase "the brush having elasticity and projecting in a radial direction perpendicular to the axis" includes not only a case where all the brushes have elasticity and projecting in a radial direction perpendicular to the axis, but also a case where a part of the brush has elasticity and projecting in a radial direction perpendicular to the axis. For example, in the case where the brush has a plurality of bristles, a brush having elasticity and a part of the plurality of bristles protruding in a radial direction perpendicular to the axis is "a brush having elasticity and protruding in a radial direction perpendicular to the axis". In the case where the brush has a plurality of bristles, the brush in which all the bristles protrude in a radial direction orthogonal to the axis and have elasticity is "a brush protruding in a radial direction orthogonal to the axis and having elasticity".

In the present invention, the phrase "the tip of the brush abuts against the inner surface of the metal pipe" includes not only a case where the brush has a plurality of brush staples and the plurality of brush staples of the brush face the inner surface of the metal pipe, a case where the tip of all the brush staples of the brush abuts against the inner surface of the metal pipe, but also a case where the tip of a part of the brush staples of the brush abuts against the inner surface of the metal pipe. Preferably, the inner elastic body is elastically displaceable in the radial direction of the rotating body.

According to the internal surface grinding device of the present embodiment, the dimension between the shaft and the tip of the brush is equal to or more than half the inner diameter of the metal pipe, and the inner elastic body elastically displaces in the radial direction. When the rotating body is inserted into the metal pipe, the inner elastic body elastically displaced in the radial direction presses the brush in the radial direction, and thereby the tip of the brush is brought into contact with the inner surface of the metal pipe in a standing state, and an internal pressure is applied to the inner surface of the metal pipe. In this state, the rotating body is rotated by the driving unit, and thereby the polishing liquid supplied to the inside of the metal pipe is pressed against the inner surface of the metal pipe by the distal end portion of the brush, and adheres to the inner surface of the metal pipe. The brush is rotated around the shaft in a state where an internal pressure is applied to the inner surface of the metal pipe by the abrasive attached to the inner surface of the metal pipe. The abrasive located between the brush and the inner surface of the metal pipe moves in the circumferential direction together with the brush on the inner surface of the metal pipe in a state where the brush presses the inner surface of the metal pipe. Thus, the inner surface of the metal pipe is polished to form a stainless steel pipe having a mirror-finished inner surface.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that, in a state where the rotating body is disposed inside the metal pipe, the tip portion of the brush is in contact with the inner surface of the metal pipe in a standing state, and an internal pressure of 80N or more is applied to the inner surface of the metal pipe. Preferably, in a state where the rotating body is disposed inside the metal tube, a tip end portion of the brush is in contact with an inner surface of the metal tube in a standing state, and an internal pressure of 300N or less is applied to the inner surface of the metal tube. Further preferably, in a state where the rotating body is disposed inside the metal tube, a tip end portion of the brush abuts against an inner surface of the metal tube in a standing state, and an internal pressure of 80N or more and 300N or less is applied to the inner surface of the metal tube.

When the internal pressure is less than 80N, the force with which the tip of the brush presses the polishing agent against the inner surface of the stainless steel pipe becomes weak, and polishing tends to be difficult. By applying an internal pressure of 80N or more to the inner surface of the metal pipe, the inner surface of the metal pipe can be prevented from being polished with difficulty. When the internal pressure is more than 300N, the brush tends to bend and hardly stand up. By applying an internal pressure of 300N or less to the inner surface of the metal pipe, the brush can be prevented from becoming hard to bend.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the rotating body has a brush holder that supports the brush and the inner elastic body disposed radially inward of the brush, and the brush holder supports the brush so as to be movable in the radial direction.

When the inner elastic body elastically displaced in the radial direction presses the brush in the radial direction, the tip portion of the brush abuts against the inner surface of the metal pipe in a standing state by the brush holder, and the inner pressure is reliably applied to the inner surface of the metal pipe. Thereby, the abrasive is more easily pressed against the inner surface of the metal pipe.

In the inner surface grinding apparatus of a metal pipe of the present invention, it is preferable that the brush holder has side walls disposed on both sides of the brush, the side walls supporting the brush to be movable in a radial direction.

Since the side wall of the brush holder supports the brush so as to be movable in the radial direction, when the inner elastic body elastically displaced in the radial direction presses the brush in the radial direction, the tip portion of the brush abuts against the inner surface of the metal pipe in a standing state, and the inner pressure is reliably applied to the inner surface of the metal pipe. This makes it easier for the abrasive to be pressed against the inner surface of the metal pipe by the brush.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the rotating body has a main body extending in an axial direction of the rotating body, the brush is disposed radially outside the main body, and the inner elastic body is disposed between the main body and the brush.

According to the above configuration, the inner elastic body can press the brush radially outward. In the above configuration, the inner elastic body may directly press the brush. By adopting the structure in which the inner elastic body directly presses the brush, the abrasive can be more easily pressed against the inner surface of the metal pipe.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the brush is disposed along an axial direction of the rotating body, and the inner elastic body is disposed radially inside the brush along the axial direction of the rotating body.

According to the above configuration, the brush can be pressed by the inner elastic body in the entire axial direction of the rotating body. In addition, the brush can be pressed uniformly in the entire axial direction of the rotating body. This enables the entire abrasive between the brush and the inner surface of the metal pipe to be reliably pressed against the inner surface of the metal pipe.

In the inner surface polishing apparatus for a metal tube according to the present invention, it is preferable that the rotating body has a plurality of the brushes, the plurality of the brushes are arranged so as to be separated from each other in a radial direction of the rotating body, and a space is formed between 2 adjacent brushes in the radial direction of the rotating body.

According to the above configuration, in a state where the rotating body is disposed inside the metal pipe, a space is formed between 2 adjacent brushes of the rotating body. In the case where the polishing liquid is supplied to the inside of the metal tube by the supply unit, the polishing liquid spreads from one end to the other end of the metal tube through the space between the adjacent 2 brushes of the rotating body. This enables the abrasive to adhere to the inner surface of the metal pipe from one end to the other end of the metal pipe.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the plurality of brushes are arranged at equal intervals in the circumferential direction of the rotating body.

The plurality of brushes are arranged at equal intervals in the circumferential direction of the rotating body, so that the internal pressures applied to the inner surface of the metal pipe by the tip portions of the brushes are substantially the same. This enables uniform grinding of the inner surface of the metal pipe in the circumferential direction.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the rotating body includes a plurality of the brushes and a plurality of the brush holders, the plurality of the brush holders support the plurality of the brushes, respectively, and the plurality of the brushes and the brush holders supporting the brushes are arranged at equal intervals in a circumferential direction of the rotating body.

The plurality of brushes are arranged at equal intervals in the circumferential direction of the rotating body, and the internal pressures applied to the inner surface of the metal pipe by the tip portions of the brushes are substantially the same. In addition, since all the brushes are supported by the brush holder so as to be movable in the radial direction, the internal pressure can be reliably applied to the inner surface of the metal pipe by all the brushes. This enables uniform grinding of the inner surface of the metal pipe in the circumferential direction.

In the inner surface polishing apparatus for a metal tube according to the present invention, it is preferable that, in a state where the rotating body is disposed inside the metal tube, when the tip portion of the brush abuts against the inner surface of the metal tube, at least a part of the tip portion of the brush is perpendicular to a tangent line at a tangent point of the tip portion abutting against the inner surface of the metal tube.

When the tip portion of the brush is perpendicular to a tangent line at a tangent point of the inner surface of the metal pipe, the inner surface of the metal pipe is reliably pressed in a radial direction with respect to a portion perpendicular to the tangent line at the tangent point of the inner surface of the metal pipe. Thus, the abrasive located between the brush and the inner surface of the metal pipe is reliably pressed against the inner surface of the metal pipe, and thus the metal pipe having a mirror-finished inner surface can be formed.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the drive unit rotates the rotating body around the shaft and moves the rotating body along the shaft.

The drive unit rotates the rotating body around the shaft and moves the rotating body along the shaft, thereby enabling the inner surface of the metal pipe to be ground even if the metal pipe is longer than the rotating body.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the plurality of rotating bodies are connected to each other in the axial direction thereof by a shaft body. Preferably, the interval between the axially adjacent rotating bodies is shorter than the axial length of the rotating bodies.

According to the above configuration, the plurality of rotating bodies are connected according to the length of the metal pipe, and thus even in the case of an elongated metal pipe having a length of, for example, 4m or more, the plurality of rotating bodies can press the polishing agent against the inner surface of the metal pipe and polish the inner surface.

In the inner surface polishing apparatus for a metal pipe according to the present invention, it is preferable that the inner elastic body is compressed in a state where the rotating body is disposed inside the metal pipe, and the inner elastic body elastically presses the brush radially outward.

According to the above configuration, the internal pressure is reliably applied to the inner surface of the metal pipe by the brush. Thus, the abrasive disposed between the distal end portion of the brush and the inner surface of the metal pipe is reliably pressed against the inner surface of the metal pipe.

The metal pipe of the present invention has an arithmetic average roughness (Ra) of less than 0.1 μm on the inner surface polished by the inner surface polishing apparatus. The metal pipe having a mirror-finished inner surface can be obtained by the inner surface grinding device.

The metal pipe of the present invention has an inner surface polished by the inner surface polishing apparatus and has a length of 4m or more. The long metal tube having a mirror-finished inner surface can be obtained by the inner surface polishing apparatus.

The "metal pipe" of the present invention is a metal pipe, a metal tubular member, or a metal pipe.

Effects of the invention

In the present invention, the dimension between the shaft of the rotating body and the front end of the brush is more than half of the inner diameter of the metal tube, and the inner elastic body elastically displaces. Thus, when the rotating body is inserted into the metal pipe, the inner elastic body, which is elastically displaced by the inward movement of the brush, elastically presses the brush in the radially outward direction. Thus, the tip end portion of the brush pressed radially outward abuts against the inner surface of the metal pipe in a standing state, and an internal pressure is applied. When the rotating body disposed inside the metal pipe is rotated in a state where the polishing liquid is supplied, the distal end portion of the brush is held in an upright state and the polishing liquid is pressed against the inner surface of the metal pipe, thereby causing the polishing agent to adhere to the inner surface of the metal pipe. The brush applies internal pressure to the metal pipe by the abrasive and the rotating body rotates around the shaft, whereby the abrasive attached to the inner surface of the metal pipe abrades the inner surface of the metal pipe in the circumferential direction. This enables the formation of a metal pipe having a mirror-finished inner surface. Further, since the dust generated when the inner surface of the metal pipe is polished is mixed into the polishing liquid, the dust can be prevented from scattering into the atmosphere. The liquid can absorb frictional heat generated by polishing the inner surface of the metal pipe with the polishing agent and cool the metal pipe. On the other hand, if the inner surface of the metal pipe is ground using a file, there is a trouble of replacing the worn file with a new one. However, since the abrasive polishes the inner surface of the metal pipe, the rotating body itself is not worn. Therefore, the trouble of replacing the rotating body with a new one can be eliminated, and the grinding time can be shortened as compared with the case of using a file.

Drawings

Fig. 1 is a schematic cross-sectional view of an inner surface polishing apparatus for a metal pipe according to an embodiment of the present invention.

Fig. 2 is a partially enlarged plan view showing a plurality of jigs connected by a shaft body.

Fig. 3 is a sectional view of the clip taken along line a-a of fig. 2.

Fig. 4 is a sectional view of a metal pipe.

Fig. 5 is a schematic cross-sectional view showing an inner surface polishing apparatus in the middle of disposing a metal pipe.

Fig. 6 is a schematic cross-sectional view showing an inner surface polishing apparatus in which a metal pipe is disposed and fixed.

Fig. 7 is a partially enlarged plan view of the metal pipe moving from the other end to the one end of the clamp unit.

Fig. 8 is a partially enlarged plan view of the other end portion of the clamp unit showing a state where the metal pipe is positioned.

Fig. 9 is an enlarged sectional view showing a part of the jig inserted inside the metal pipe.

Fig. 10 is a partially enlarged sectional view showing a brush tip portion of fig. 9.

Fig. 11 is a cross-sectional view taken along line B-B of fig. 8 in a state where the polishing liquid is supplied to the inside of the metal pipe and the holder is rotated.

Fig. 12 is a partially enlarged sectional view of the clip of fig. 11.

Detailed Description

Hereinafter, embodiments of the present invention will be described with reference to the drawings.

The inner surface polishing apparatus 10 of the present embodiment shown in fig. 1 polishes the inner surface of an elongated metal tube (material to be polished) having a length of 4 m. Here, the metal pipe is exemplified as a stainless steel pipe. In the present embodiment, examples and comparative examples described later, the "stainless steel pipe" is a pipe made of stainless steel, a cylindrical member made of stainless steel, or a pipe made of stainless steel. The stainless steel pipe whose inner surface is polished by the inner surface polishing apparatus 10 is used in an apparatus for producing food or medicine, but the use is not particularly limited. The arithmetic mean roughness (Ra) of the inner surface of the stainless steel pipe polished by the inner surface polishing apparatus 10 is less than 0.1. mu.m.

The inner surface polishing apparatus 10 is not limited to a stainless steel pipe, and can polish the inner surface of a pipe, a cylindrical member, or a pipe made of a metal other than stainless steel such as titanium or brass. In the present embodiment, a long stainless steel pipe having a length of 4m is polished, but the length of the metal pipe to be polished is not particularly limited. The inner surface of the metal pipe shorter than 4m may be polished, or the inner surface of the metal pipe longer than 4m, for example, 6m may be polished.

As will be described later, the inner surface polishing apparatus 10 polishes the inner surface of the stainless steel pipe with a wet polishing agent mixed in a liquid. Therefore, the inner surface polishing apparatus 10 is covered with a box-shaped cover (not shown) to prevent the liquid from leaking to the outside, but the cover is omitted here for convenience of description.

Fig. 6 shows a state in which a stainless steel pipe (metal pipe) 1 is disposed in the inner surface polishing apparatus 10 shown in fig. 1. Referring also to fig. 6, the inner surface polishing apparatus 10 includes: a pump (supply means) 12 (see fig. 6) as supply means for supplying the polishing liquid to the inside of the stainless steel pipe 1 in a state where the stainless steel pipe 1 is disposed and fixed; a jig (rotating body) 21 (see fig. 1) as a rotating body that rotates inside the stainless steel pipe 1; and a motor (driving means) 30 (see fig. 1 and 6) as a driving means for driving the jig 21 to rotate around the shaft 23.

As shown in fig. 6, the pump 12 is in communication with a tank 13 for storing the slurry. The polishing liquid in the tank 13 is discharged from the tip 14 of the pump 12. In a state where the stainless steel pipe 1 is disposed in the inner surface polishing apparatus 10, the tip 14 of the pump 12 is connected to an end opening of the stainless steel pipe 1 on the side opposite to the motor 30 via a pipe (not shown). While the stainless steel pipe 1 is disposed and operated in the inner surface polishing apparatus 10, the pump 12 discharges and supplies the polishing liquid to the inside of the stainless steel pipe 1. The polishing liquid supplied to the stainless steel pipe 1 is discharged from the end opening of the stainless steel pipe 1 on the motor 30 side. The discharged slurry flows to a recovery unit 16 disposed below the stainless steel pipe 1 and the jig 21 (see fig. 1), and is stored in a drain pan 17. The recovery unit 16 is formed integrally with a cover, not shown.

The polishing liquid is a mixture of a liquid and a particulate polishing agent. In the present embodiment, water is used as the liquid, but is not limited thereto. The liquid may be, for example, acidic water or an organic solvent. In particular, the liquid may be an alcohol, oil, ethanol or nitric acid. The material of the liquid is not particularly limited as long as it can be used for polishing of metal by mixing with a polishing agent.

In the present embodiment, alumina is used as the polishing agent, but the present invention is not limited thereto. As the polishing agent, for example, a wet polishing agent is used. The polishing agent preferably has a higher specific gravity than water and a higher hardness than the metal to be polished. As such a polishing agent, for example, carbide or oxide is used. Specifically, as the abrasive, carbon or diamond may be used. The material of the polishing agent is not particularly limited as long as it can be used for polishing metal by being mixed with a liquid.

The inner surface of the stainless steel pipe 1 is polished by pressing a polishing agent against the inner surface of the stainless steel pipe 1 with a jig 21 (see fig. 1). The internal surface polishing apparatus 10 of the present embodiment includes 8 jigs 21, and these jigs 21 are connected to each other in the direction of a shaft 23 via a shaft body 22. That is, the inner surface of the stainless steel pipe 1 (see fig. 6) of 4m was polished using 8 jigs 21. For convenience of description, in the following description, the 8 jigs 21 and the shaft body 22 are collectively referred to as a jig unit 20.

As shown in fig. 1, one end portion (one end portion of the shaft body 22) of the gripper unit 20 on the motor 30 side is rotatably supported by the motor 30. The other end portion (the other end portion of the shaft body 22) of the jig unit 20 on the opposite side to the motor 30 is supported by a support leg 33c erected on the ground. In the jig unit 20, a part of the shaft body 22 is supported by a plurality of support legs, not shown, disposed at predetermined intervals between the motor 30 and the support leg 33 c. The tip end portion of the support leg 33c is supported by the clamping shaft body 22, and the support and release of the support of the gripper unit 20 can be performed by opening and closing the tip end portion. When the stainless steel pipe 1 is moved from the other end portion to the one end portion of the gripper unit 20 while covering the gripper unit 20 with the stainless steel pipe 1, the support legs 33c release the support of the gripper unit 20.

Fig. 2 is a partially enlarged plan view showing the other end side 3 jigs 21 arranged apart from the motor 30 in the jig unit 20. The gripper unit 20 has 8 grippers 21, but only 3 grippers 21 are shown here as a representative. Each of the 8 jigs 21 is of the same shape, and the length dimension of the jig 21 is L1. The adjacent jigs 21 are arranged at equal intervals of L2. The interval L2 between the clips 21 and the clips 21 is shorter than the length L1 of the clips 21.

Fig. 3 is a cross-sectional view taken along line a-a of fig. 2, and is an enlarged cross-sectional view of the jig 21 in a direction orthogonal to the axis 23. The jig 21 is fixed to the shaft body 22 and rotates together with the shaft body 22. The jig 21 has: a main body 41 extending in the direction of the shaft 23; a brush 44 which projects radially outward from the main body 41 and is provided radially outward and movable in the radial direction; and a tube (inner elastic body) 45 which is an inner elastic body disposed between the shaft 23 and the brush 44 and elastically pressing the brush 44 radially outward.

The main body 41 has a cylindrical cross section perpendicular to the shaft 23, and 3 brush holders 48 having concave cross sections are formed integrally with the main body 41 at equal intervals in the circumferential direction of the main body 41. The base 44a of the brush 44 and the pipe 45 are disposed inside the brush holder 48. The brush 44 and the tube 45 are supported by a brush holder 48.

The brush 44 is made of numerous resins (bristles) extending linearly, and has elasticity. Here, the brush 44 is a concept including a base 44a in which innumerable resins are implanted. Each resin constituting the brush 44 of the present embodiment has a circular cross section in a direction orthogonal to the extending direction. The diameter of each resin of the brush 44 (the diameter of a surface perpendicular to the longitudinal direction) is not particularly limited as long as the brush 44 can maintain the standing state when the jig 21 inserted inside the stainless steel pipe 1 rotates. For example, a resin having a diameter (hereinafter, referred to as a wire diameter) of 0.2mm or more and 0.6mm or less may be linearly extended.

The brush 44 is supported on the side wall 48a of the brush holder 48 so as to be movable in the radial direction. The brush 44 is arranged radially outward of the tube 45 and extends straight in parallel with the shaft 23. In the present embodiment, 3 brushes 44 are arranged at equal intervals in the circumferential direction of the main body 41. In addition, the number of brushes 44 is not limited to 3. The brush 44 supported by the brush holder 48 protrudes from the main body 41 in a direction (radial direction) orthogonal to the shaft 23, and stands up in the radial direction. The brush 44 is elastically pressed radially outward by the tube 45, and is locked to a stopper (not shown) provided in the brush holder 48, thereby maintaining a supported state by the brush holder 48. The dimension L3 between the tip of the brush 44 and the shaft 23 is larger than the dimension L4 (see fig. 4) which is half the inner diameter of the stainless steel pipe 1. In addition, the brush 44 and the front end portion thereof standing up means that the brush 44 and the front end portion thereof stand up, and the case where the brush 44 and the front end portion thereof are bent or bent is not included.

The inner elastic member is a resin tube 45 and has elasticity. The pipe 45 is disposed between the shaft 23 and the brush 44 in the brush holder 48, i.e., is disposed radially inward of the brush 44. The tube 45 disposed in the brush holder 48 is disposed between the bottom wall 48b of the brush holder 48 and the brush 44, and is elastically displaced. The tube 45 is in contact with the brush 44, and presses the brush 44 directly toward the radial outside. In addition, since the tube 45 extends from one end to the other end of the brush 44 in the longitudinal direction of the brush 44 (the direction parallel to the shaft 23), the tube 45 can uniformly press the brush 44 over the entire longitudinal direction of the brush 44.

Returning to fig. 1, the motor 30 rotates the gripper 21 about the shaft 23 and moves the gripper 21 along the shaft 23. The motor 30 is fixed to a base plate 32, and the base plate 32 is provided to be movable in the direction of the shaft 23 on a pair of guide rails 31. The pair of guide rails 31 are arranged side by side in the horizontal direction, and are fixed to a support plate 34, and the support plate 34 is attached to a support leg 33a and a support leg 33b erected on the ground.

In addition, the base plate 32 is driven along the shaft 23 by a rack and pinion. A motor, not shown, is mounted on the base plate 32, and rotates a pinion gear 37 via a shaft body 36. The motor 30 moves along the shaft 23 together with the base plate 32 by rotating a pinion 37 that meshes with a rack 38 mounted on the

support legs

33a and 33 b.

Hereinafter, a method of polishing the inner surface of the stainless steel pipe 1 by the inner surface polishing apparatus 10 will be described.

Fig. 5 is a schematic cross-sectional view showing the inner surface polishing apparatus 10 in the middle of installation of the stainless steel pipe 1. In fig. 5, the stainless steel pipe 1 is moved in the direction of the shaft 23 so as to cover the jig 21 from the other end to the one end of the jig unit 20 (see fig. 7) for positioning. Fig. 8 is a partially enlarged plan view showing the other end portion of the gripper unit 20 in a state where the stainless steel pipe 1 is positioned. When the stainless steel pipe 1 is positioned and fixed, all the jigs 21 are disposed inside the stainless steel pipe 1. When the stainless steel pipe 1 is positioned, the end opening of the stainless steel pipe 1 on the opposite side of the motor 30 is connected to the tip 14 (see fig. 6) of the pump 12 via a pipe (not shown), and the polishing liquid in the tank 13 can be supplied to the inside of the stainless steel pipe 1.

As shown in fig. 3, a dimension L3 between the tip of the brush 44 and the shaft 23 is larger than a dimension L4 that is half the inner diameter of the stainless steel pipe 1. Therefore, as shown in fig. 9, when the jig 21 is inserted into the stainless steel pipe 1, the brush 44 moves radially inward, and the pipe 45 is compressed. Thus, the tube 45 elastically presses the brush 44 radially outward, and the tip end portion of the brush 44 abuts against the inner surface of the stainless steel tube 1 in a state where the brush 44 stands up, thereby applying a constant internal pressure. At this time, as shown in fig. 10, the tip of at least a part of the brush 44 vertically abuts against the inner surface of the stainless steel pipe 1. In the present embodiment, the internal pressure applied to the inner surface of the stainless steel pipe 1 by the distal end portion of the brush 44 is preferably 80N or more. In the present embodiment, the internal pressure applied to the inner surface of the stainless steel pipe 1 by the distal end portion of the brush 44 is preferably set to 300N or less. When the internal pressure is less than 80N, the force with which the distal end portion of the brush 44 presses the polishing agent against the inner surface of the stainless steel pipe 1 becomes weak, and polishing tends to be difficult. On the other hand, when the internal pressure is greater than 300N, the brush 44 tends to bend and be hard to stand.

When the polishing liquid is supplied from the tank 13 shown in fig. 6 to the inside of the stainless steel pipe 1, the polishing liquid passes through a space S (see fig. 11) formed between the inner surface of the stainless steel pipe 1 and the surface of the jig 21, and spreads from one end to the other end of the stainless steel pipe 1. In this state, when the motor 30 rotates the holder 21 around the shaft 23, the polishing liquid moves to the tip of the brush 44 by centrifugal force and is collected. Then, the tip of the brush 44 presses the polishing liquid against the inner surface of the stainless steel pipe 1, whereby the polishing agent 2 adheres to the inner surface of the stainless steel pipe 1. Further, since the tube 45 elastically presses the brush 44 in the radially outward direction, the brush 44 and the tip end portion thereof are kept in the standing state while the jig 21 is rotated (see fig. 12). In this way, the brush 44 applies internal pressure to the stainless steel pipe 1 by the abrasives 2 and rotates around the shaft 23, so that the abrasives 2 adhering to the inner surface of the stainless steel pipe 1 polish the inner surface of the stainless steel pipe 1 in the circumferential direction.

As described above, in the present embodiment, when the jig 21 is inserted into the inside of the stainless steel pipe 1, the pipe 45 is elastically displaced (compressed) inward. The tube 45 elastically displaced inward elastically presses the brush 44 radially outward. Thus, the tube 45 is pressed radially outward, and the tip of the brush 44 is in contact with the inner surface of the metal tube in a standing state, thereby applying an internal pressure. When the polishing liquid is supplied into the stainless steel pipe 1 and the jig 21 is rotated, the tip of the brush 44 is rotated while being held in an upright state. At this time, the tip of the brush 44 presses the attached abrasive against the inner surface of the stainless steel pipe 1, thereby polishing the inner surface in the circumferential direction with the abrasive. That is, the present invention relates to an apparatus for grinding the inner surface of a metal pipe using only physical grinding.

The motor 30 rotates the gripper 21 about the shaft and moves the gripper 21 along the shaft 23. Since the adjacent jigs 21 are arranged at equal intervals, the motor 30 moves the jigs 21 in the direction of the shaft 23 by the interval L2 between the jigs 21 and the jigs 21. Thereby, the entire inner surface of the stainless steel pipe 1 is polished by the jig 21 and the polishing agent 2. By disposing the

adjacent jigs

21 and 21 at the interval L2 in this way, the driving force for rotating the jigs 21 about the shaft 23 can be suppressed, and the motor 30 can be downsized or the power consumption can be reduced, as compared with the case of using 1 jig extending in the entire longitudinal direction of the stainless steel pipe 1. In addition, the reaction force received from the inner surface of the stainless steel pipe 1 can be suppressed, and the clamp unit 20 can be prevented from being damaged.

[ features of the internal surface polishing apparatus of the present embodiment ]

The inner surface polishing apparatus 10 of the stainless steel pipe 1 of the present embodiment has the following features.

In the internal surface polishing apparatus 10 of the present embodiment, as shown in fig. 3, the dimension between the shaft 23 of the jig 21 and the tip of the brush 44 is equal to or more than half the inner diameter L4 of the stainless steel pipe 1, and the pipe 45 itself is elastically displaced. Thus, when the jig 21 is inserted into the stainless steel pipe 1, the pipe 45 elastically displaced inward presses the brush 44 radially outward. The tip of the brush 44 pressed radially outward abuts against the inner surface of the stainless steel pipe 1 in an upright state, and applies internal pressure. Therefore, when the jig 21 disposed inside the stainless steel pipe 1 is rotated in a state where the polishing liquid is supplied, the distal end portion of the brush 44 presses the polishing liquid against the inner surface of the stainless steel pipe 1, and the polishing agent can be attached to the inner surface of the stainless steel pipe 1. The brush 44 applies internal pressure to the stainless steel pipe 1 by the abrasives and the jig 21 rotates around the shaft 23, whereby the abrasives 2 attached to the inner surface of the stainless steel pipe 1 abrade the inner surface of the stainless steel pipe 1 in the circumferential direction. This enables the formation of the stainless steel pipe 1 having a mirror-finished inner surface.

In the inner surface polishing apparatus 10 of the present embodiment, dust generated when polishing the inner surface of the stainless steel pipe 1 is mixed into the polishing liquid, and therefore, the dust can be prevented from scattering into the atmosphere. The liquid can absorb frictional heat generated by polishing the inner surface of the stainless steel pipe 1 with the polishing agent 2 and cool the same. On the other hand, if the inner surface of the stainless steel pipe is ground using a file, there is a trouble of replacing the worn file with a new one. However, in the present invention, since the abrasive 2 polishes the inner surface of the stainless steel pipe 1, the jig 21 itself is not abraded. Therefore, the trouble of replacing the new jig 21 can be eliminated, and the grinding time can be shortened.

In the internal surface polishing apparatus 10 of the present embodiment, it is preferable that the tip end portion of the brush 44 is in contact with the inner surface of the metal pipe in a standing state, and an internal pressure of 80N or more is applied. In the internal surface polishing apparatus 10 of the present embodiment, it is preferable to apply an internal pressure of 300N or less. When the internal pressure is less than 80N, the force with which the distal end portion of the brush 44 presses the polishing agent against the inner surface of the stainless steel pipe 1 tends to be weak and difficult to polish, but this tendency can be suppressed. On the other hand, when the internal pressure is higher than 300N, the brush 44 tends to bend and hardly stand up, but this can be suppressed.

In the internal surface polishing apparatus 10 of the present embodiment, the tube 45 disposed between the shaft 23 and the brush 44 may extend in the longitudinal direction of the brush 44 (the direction parallel to the shaft 23). Thereby, the tube 45 can uniformly press the brush 44 in the entire length direction of the brush 44.

In the inner surface polishing apparatus 10 of the present embodiment, since the plurality of brushes 44 are arranged at equal intervals in the circumferential direction of the main body, the internal pressure applied by the tip portions of the plurality of brushes 44 contacting the inner surface of the stainless steel pipe 1 can be made uniform.

In the inner surface polishing apparatus 10 of the present embodiment, in a state where the jig 21 is disposed inside the stainless steel pipe 1, the fact that the tip portion of the brush 44 vertically abuts against the inner surface of the stainless steel pipe 1 means that the tip portion of the brush 44 abuts against the inner surface of the stainless steel pipe 1 in an upright state and internal pressure is applied. In this state, the brush 44 applies internal pressure to the stainless steel pipe 1 with the abrasives 2 and the jig 21 is rotated around the shaft 23, whereby the abrasives 2 attached to the inner surface of the stainless steel pipe 1 abrade the inner surface of the stainless steel pipe 1 in the circumferential direction. Therefore, the stainless steel pipe 1 having a mirror-finished inner surface can be formed.

In the internal surface polishing apparatus 10 of the present embodiment, the polishing liquid is injected from one end of the stainless steel pipe 1 toward the other end thereof in a state where the jig 21 is disposed inside the stainless steel pipe 1. As shown in fig. 11, since a space S is formed between the inner surface of the stainless steel pipe 1 and the surface of the jig 21, the polishing liquid injected into the stainless steel pipe 1 can flow from one end to the other end of the stainless steel pipe 1 through the space S.

In the internal surface polishing apparatus 10 of the present embodiment, as shown in fig. 1, the motor 30 rotates the jig 21 around the shaft 23 and moves the jig 21 along the shaft 23. Thus, the entire inner surface of the stainless steel pipe 1, which is longer than the jig 21, can be polished.

In the internal surface polishing apparatus 10 of the present embodiment, the jig 21 is connected to the shaft 23 direction thereof by the shaft body 22. By connecting the plurality of clamps 21 according to the length of the metal pipe, the plurality of clamps 21 can press the polishing agent 2 against the inner surface of the metal pipe to polish even an elongated metal pipe having a length of, for example, 4m or more.

< example >

The inventors of the present application measured the arithmetic mean roughness (Ra) of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing apparatus 10 and compared it with the arithmetic mean roughness (Ra) of the inner surface of the conventional stainless steel pipe.

< Table 1>

Table 1 shows a graph showing the arithmetic average roughness (Ra) in the circumferential direction of the inner surface of the stainless steel pipe polished by the conventional longitudinal polishing as a comparative example. In the longitudinal grinding, the inner surface of the stainless steel pipe was ground in 5 steps in total, using a 90 grit file in the 1 st step, a 120 grit file in the 2 nd step, a 140 grit file in the 3 rd step, a 240 grit file in the 4 th step, and a 400 grit file in the 5 th step. The particle size of the file is defined in "the specification of the particle size of the abrasive for polishing cloth and paper according to JISR 6010" in JIS standard. In a plurality of stainless steel pipes polished by such longitudinal polishing, when the arithmetic average roughness (Ra) in the circumferential direction was measured for arbitrary 2, the 1 st was 0.7576 μm, and the 2 nd was 0.6103 μm.

< Table 2>

Table 2 shows a graph in which the circumferential arithmetic mean roughness (Ra) of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing apparatus 10 of the present invention is measured. In this polishing, a polishing liquid in which water as a liquid and alumina as a polishing agent are mixed is used. In the first step 1, a brush 44 having a wire diameter of 0.5mm was used, and the jig 21 was rotated at 300rpm for 30 minutes. At any time, in the 1 st step, when the measuring brush 44 presses the internal pressure of the inner surface of the stainless steel pipe 1, the internal pressure is 120N or more and 160N or less. In the next 2 nd step, the brush 44 having a wire diameter of 0.4mm was used, and the jig 21 was rotated at 300rpm for 30 minutes. At any time, in the 2 nd step, when the measuring brush 44 presses the internal pressure of the inner surface of the stainless steel pipe 1, the internal pressure is 160N or more and 270N or less. When the arithmetic mean roughness (Ra) in the circumferential direction was measured for any 2 of the plurality of stainless steel pipes polished by these 2 steps, the 1 st was 0.093 μm, and the 2 nd was 0.096 μm. As is clear from the above, the arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe 1 of the present invention is less than 0.1. mu.m. The arithmetic average roughness (Ra) is based on the specification of JISB 0031 (1994).

While the embodiments of the present invention have been described above with reference to the drawings, the specific configurations should not be construed as being limited to these embodiments. The scope of the present invention is indicated not only by the description of the above embodiments but also by the claims, and all modifications within the meaning and scope equivalent to the claims are also included.

In the above embodiment, the inner surface of the stainless steel pipe 1 having a length of 4m was polished by 8 jigs 21, but is not limited thereto. It is also possible to use 1 jig of the same length as the length of the stainless steel tube. At this time, the motor 30 and the jig 21 may not be moved in the direction of the shaft 23 (see fig. 1 and the like). The number of jigs is not limited to 8, and a plurality of jigs such as 2, 3, and the like may be used.

In the above embodiment, as shown in fig. 2, the interval between the adjacent 2 jigs 21 is L2, and the interval L2 is shorter than the length L1 of the jig 21, but the present invention is not limited thereto. The interval L2 may be the same as the length L1 of the jig or longer than the length L1 of the jig as long as the motor 30 can be moved in the axial direction to grind the entire inner surface of the stainless steel pipe.

In the above embodiment, the dimension L3 (see fig. 3) between the tip of the brush 44 and the shaft 23 is larger than the dimension L4 (see fig. 4) which is half the inner diameter of the stainless steel pipe 1, but the dimension L3 and the dimension L4 may be equal to each other.

In the above embodiment, the inner elastic body disposed between the shaft 23 and the brush 44 is the tube 45 having elasticity (see fig. 3), but is not limited thereto. The inner elastic body may also be a spring or rubber, for example.

In the above embodiment, as shown in fig. 3, the case where the base portion 44a of the brush 44 is disposed inside the brush holder 48 is shown, but a part of the base portion 44a may be disposed inside the brush holder 48, or at least a part of the base portion 44a and a plurality of resins (bristles) implanted in the base portion 44a may be disposed.

In the above embodiment, as shown in fig. 3, the brush holder 48 has the side wall 48a and the bottom wall 48b, but the structure of the brush holder may be changed.

In the above embodiment, as shown in fig. 3, the base portion 44a of the brush 44 is disposed radially outside the tube 45, and the tube 45 directly presses the base portion 44a of the brush 44. However, another member may be disposed between the tube 45 and the brush 44.

In the above embodiment, as shown in fig. 3, the brush 44 and the brush holder 48 supporting the brush 44 are arranged at 3 positions at equal intervals in the circumferential direction of the jig 21. However, the brush 44 and the brush holder 48 supporting the brush 44 may not be arranged at equal intervals in the circumferential direction of the jig 21. The brush 44 and the brush holder 48 supporting the brush 44 may also be arranged at 1, 2, or 4 or more positions in the circumferential direction of the jig 21. The brush 44 and the pipe 45 disposed radially inward thereof may be disposed continuously over the entire circumference of the jig 21.

Description of the reference numerals

1 stainless steel tube (ground material)

2 abrasive

10 inner surface grinding device

12 pump (supply unit)

21 clamp (rotating body)

22 shaft body

23 shaft

30 Motor (drive unit)

41 main body

44 brush

45 tubes (inner elastomer)

S space

Claims

1. An inner surface polishing apparatus for polishing an inner surface of a metal pipe as a material to be polished, comprising:

a rotating body extending in an axial direction;

a driving unit that rotates the rotating body around a shaft; and

a supply unit for supplying a polishing liquid obtained by mixing a granular polishing agent and a liquid to the inside of the metal pipe,

the rotating body includes a brush having elasticity and projecting in a radial direction perpendicular to the axis, and an inner elastic body disposed radially inward of the brush,

the dimension between the shaft and the front end of the brush is more than half of the inner diameter of the metal tube,

in a state where the rotating body is disposed inside the metal pipe, the inner elastic body presses the brush radially outward, whereby a tip portion of the brush abuts against an inner surface of the metal pipe in a standing state, and internal pressure is applied to the inner surface of the metal pipe, whereby the abrasive supplied from the supply unit to the inner surface of the metal pipe adheres to the inner surface of the metal pipe, and the inner surface of the metal pipe is pressed by the tip portion of the brush, thereby polishing the inner surface.

2. The apparatus according to claim 1, wherein the brush has a tip portion that is in contact with the inner surface of the metal pipe in an upright state in a state in which the rotating body is disposed inside the metal pipe, and an internal pressure of 80N or more is applied to the inner surface of the metal pipe.

3. The apparatus according to claim 1 or 2, wherein the brush has a tip portion that is in contact with the inner surface of the metal pipe in an upright state in a state in which the rotating body is disposed inside the metal pipe, and an internal pressure of 300N or less is applied to the inner surface of the metal pipe.

4. The apparatus for grinding an inner surface of a metal pipe according to any one of claims 1 to 3,

the rotating body has a brush holder that supports the brush and the inner elastic body disposed radially inside the brush,

the brush holder supports the brush to be movable in a radial direction.

5. The apparatus for grinding the inner surface of a metal pipe according to claim 4,

the brush holder has side walls disposed at both sides of the brush,

the side wall supports the brush and enables it to move in a radial direction.

6. The apparatus for grinding an inner surface of a metal pipe according to any one of claims 1 to 5,

the rotating body has a main body extending in an axial direction of the rotating body,

the brush is disposed radially outward of the body,

the inner elastic body is disposed between the main body and the brush.

7. The apparatus for grinding an inner surface of a metal pipe according to any one of claims 1 to 6,

the brush is disposed along an axial direction of the rotating body,

the inner elastic body is disposed along the axial direction of the rotating body on the radially inner side of the brush.

8. The apparatus for grinding an inner surface of a metal pipe according to any one of claims 1 to 7,

the rotating body has a plurality of the brushes,

a plurality of the brushes are arranged separately in a radial direction of the rotating body,

a space is formed between 2 of the brushes adjacent in the radial direction of the rotating body.

9. The apparatus for grinding an inner surface of a metal pipe as recited in any one of claims 1 to 8, wherein the plurality of brushes are arranged at equal intervals in a circumferential direction of the rotating body.

10. The apparatus for grinding the inner surface of a metal pipe as claimed in claim 4 or 5,

the rotating body has a plurality of the brushes and a plurality of the brush holders,

the plurality of brush holders support the plurality of brushes respectively,

the plurality of brushes and brush holders supporting the brushes are arranged at equal intervals in the circumferential direction of the rotating body.

11. The apparatus according to any one of claims 1 to 10, wherein at least a part of the tip portion of the brush is perpendicular to a tangent line at a tangent point where the tip portion abuts the inner surface of the metal pipe when the tip portion of the brush abuts the inner surface of the metal pipe in a state where the rotating body is disposed inside the metal pipe.

12. The apparatus for grinding an inner surface of a metal pipe according to any one of claims 1 to 11, wherein the driving unit rotates the rotating body about the shaft and moves the rotating body along the shaft.

13. The apparatus for grinding an inner surface of a metal pipe as claimed in any one of claims 1 to 12, wherein a plurality of the rotating bodies are connected in an axial direction thereof by a shaft body.

14. The apparatus for grinding an inner surface of a metal pipe as set forth in claim 13, wherein an interval between the rotating bodies adjacent in the axial direction is shorter than a length of the rotating bodies in the axial direction.

15. The apparatus according to any one of claims 1 to 14, wherein the inner elastic body is compressed in a state where the rotating body is disposed inside the metal tube, and the inner elastic body elastically presses the brush radially outward.

16. A metal pipe characterized in that the arithmetic average roughness (Ra) of the inner surface ground by the inner surface grinding apparatus of any one of claims 1 to 15 is less than 0.1 μm.

17. A metal pipe characterized in that an inner surface is ground by the inner surface grinding device according to any one of claims 1 to 16 to have a length of 4m or more.