CN114007811B

CN114007811B - Inner surface grinding device for metal tube and metal tube

Info

Publication number: CN114007811B
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: 2023-12-08
Anticipated expiration: 2040-06-25
Also published as: EP3991914A1; EP3991914A4; WO2020262562A1; JP6663067B1; CN114007811A; JP2021003748A

Abstract

In the application, the clamp (21) is provided with a brush (44) and a tube (46), wherein the brush (44) protrudes in the radial direction orthogonal to the shaft (23) and has elasticity, and the tube (46) is arranged at the position on 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 tube (1). In a state where the jig (21) is disposed inside the stainless steel pipe (1), the pipe (46) presses the brush (44) radially outward, whereby the tip end of the brush (44) abuts against the inner surface of the stainless steel pipe (1) in a standing state and internal pressure is applied. Thereby, the abrasive supplied from the pump (12) adheres to the inner surface of the stainless steel pipe (1). The abrasive adhering 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 tube and metal tube

Technical Field

The present application relates to an apparatus for polishing an inner surface of a metal pipe and a metal pipe having an inner surface polished by the apparatus.

Background

Conventionally, in the case of polishing the inner surface of a metal pipe, there is known a method of finishing the inner surface with a polishing material having a large particle size after a substrate treatment with a polishing material having a small particle size. Such a polishing method is employed in so-called vertical polishing (see patent document 1), in which a polishing belt is pressed against the inner surface of a metal pipe, and the inner surface of the metal pipe is polished by moving the polishing belt in the longitudinal direction of the metal pipe.

Prior art literature

Patent literature

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

Disclosure of Invention

Technical problem to be solved by the application

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

Further, the problem in the vertical polishing described in patent document 1 is: dust generated when polishing the inner surface of the metal pipe is scattered into the atmosphere, or the polishing time is prolonged in order to replace the worn polishing belt with a new one.

Accordingly, the present application has been made to solve the above-mentioned problems, and an object of the present application is to provide a metal pipe inner surface polishing apparatus capable of forming a metal pipe having a mirror-finished inner surface, and a metal pipe having an inner surface polished by using the apparatus.

The present application also provides an inner surface polishing apparatus for a metal pipe capable of preventing dust generated during polishing from scattering into the atmosphere and reducing polishing time as compared with conventional vertical polishing, and a metal pipe for polishing an inner surface using the apparatus.

Means for solving the problems

The present application provides an apparatus for polishing an inner surface of a metal pipe, which is a material to be polished, comprising: a rotating body extending in an axial direction; a driving unit that rotates the rotating body around the shaft; and a supply unit that supplies the polishing liquid, in which the granular polishing agent and the liquid are mixed, to the inside of the metal pipe, wherein the rotating body includes a brush that protrudes in a radial direction orthogonal to the shaft and has elasticity, the inside elastic body is disposed at a position radially inward of the brush, a dimension between the shaft and a tip of the brush is half or more of an inner diameter of the metal pipe, and in a state in which the rotating body is disposed inside the metal pipe, the inside elastic body presses the brush radially outward, whereby the tip of the brush is brought into contact with the inner surface of the metal pipe in a standing state, and an inner pressure is applied to the inner surface of the metal pipe, whereby the polishing agent 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 is polished by pressing the tip of the brush against the inner surface of the metal pipe.

In the present application, the term "metal pipe" refers to a metal pipe, a metal tubular member, or a metal pipe. In the present application, the "inner surface polishing device for a metal pipe" refers to "an inner surface polishing device for a metal pipe", "an inner surface polishing device for a metal tubular member", or "an inner surface polishing device for a metal pipe".

In the present application, the term "brush having elasticity and protruding in a radial direction perpendicular to the axis" means not only a case where all brushes have elasticity and protruding in a radial direction perpendicular to the axis, but also a case where a part of the brushes have elasticity and protruding 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 in which a part of the plurality of bristles protrudes in a radial direction orthogonal to the axis is "a brush having elasticity in a radial direction orthogonal to the axis". In the case of a brush having a plurality of bristles, a brush having elasticity in which all the bristles protrude in a radial direction orthogonal to the axis is "a brush having elasticity in a radial direction orthogonal to the axis".

In the present application, the term "the tip portion of the brush abuts against the inner surface of the metal tube" includes not only a case where the brush has a plurality of bristles and the plurality of bristles of the brush face the inner surface of the metal tube, but also a case where the tip portions of all the bristles of the brush abut against the inner surface of the metal tube, and a case where the tip portions of a part of the bristles of the brush abut against the inner surface of the metal tube. Preferably, the inner elastic body is elastically displaceable in the radial direction of the rotating body.

According to the inner surface polishing apparatus of the present embodiment, the dimension between the shaft and the tip of the brush is half or more of the inner diameter of the metal pipe, and the inner elastic body is elastically displaced in the radial direction. When the rotor is inserted into the inner side of the metal pipe, the inner elastic body elastically displaced radially inward presses the brush radially outward, whereby the tip end portion of the brush abuts against 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 tip portion of the brush, and adheres to the inner surface of the metal pipe. The brush rotates around the shaft in a state that an inner 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 along with the brush at the inner surface of the metal pipe in a state of being pressed against the inner surface of the metal pipe by the brush. 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 device for a metal pipe according to the present application, it is preferable that the brush has a tip portion that abuts against the inner surface of the metal pipe in a raised state in a state where 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. Preferably, in a state where the rotating body is disposed inside the metal pipe, the tip end portion of the brush is in contact with the inner surface of the metal pipe in a standing state, and an internal pressure of 300N or less is applied to the inner surface of the metal pipe. Further preferably, in a state where the rotating body is disposed inside the metal pipe, the tip end 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 to 300N is applied to the inner surface of the metal pipe.

When the internal pressure is less than 80N, the force with which the polishing agent is pressed against the inner surface of the stainless steel pipe by the tip portion of the brush 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 suppressed from being difficult to polish. When the internal pressure is more than 300N, the brush tends to bend and be difficult to stand up. By applying an internal pressure of 300N or less to the inner surface of the metal pipe, it is possible to suppress the brush from becoming difficult to bend.

In the inner surface polishing apparatus for a metal pipe of the present application, 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 that the brush holder supports the brush so as to be movable in the radial direction.

When the brush is pressed radially outward by the inner elastic body elastically displaced radially inward, the tip end portion of the brush is brought into contact with the inner surface of the metal tube in a standing state by the brush holder, and the inner pressure is reliably applied to the inner surface of the metal tube. Thereby, the abrasive is more easily pressed against the inner surface of the metal tube.

In the metal pipe inner surface polishing apparatus of the present application, it is preferable that the brush holder has side walls arranged on both sides of the brush, the side walls supporting the brush so as to be movable in the 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 radially outward, the tip end portion of the brush abuts against the inner surface of the metal tube in a standing state, and the inner pressure is reliably applied to the inner surface of the metal tube. Thus, the abrasive is easily pressed against the inner surface of the metal pipe by the brush.

In the metal pipe inner surface polishing apparatus according to the present application, 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 outward of 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 is more easily pressed against the inner surface of the metal pipe.

In the metal pipe inner surface polishing device according to the present application, it is preferable that the brush is disposed along the axial direction of the rotating body, and the inner elastic body is disposed along the axial direction of the rotating body radially inward of the brush.

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

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

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

In the metal pipe inner surface polishing apparatus according to the present application, 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, whereby the inner pressure applied to the inner surface of the metal pipe by the tip portions of the brushes is substantially the same. Thereby, the inner surface of the metal pipe can be uniformly polished in the circumferential direction.

In the inner surface polishing device for a metal pipe according to the present application, it is preferable that the rotating body has a plurality of brushes and a plurality of brush holders, the plurality of brush holders respectively support the plurality of brushes, and the plurality of 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 inner pressure applied to the inner surface of the metal pipe by the tip portions of the brushes is substantially the same. In addition, since all brushes are supported by the brush holder so as to be movable in the radial direction, the inner pressure can be reliably applied to the inner surface of the metal tube by all brushes. Thereby, the inner surface of the metal pipe can be uniformly polished in the circumferential direction.

In the inner surface polishing device for a metal pipe according to the present application, it is preferable that, in a state where the rotating body is disposed inside the metal pipe, when the tip end portion of the brush is in contact with the inner surface of the metal pipe, at least a part of the tip end portion of the brush is perpendicular to a tangent line at a point of contact with the inner surface of the metal pipe.

When the distal end portion of the brush is in contact with the inner surface of the metal pipe in a state in which the rotating body is disposed inside the metal pipe, the inner surface of the metal pipe is reliably pressed in the radial direction against a portion perpendicular to a tangent line at a tangent point in contact with the inner surface of the metal pipe when at least a portion of the distal end portion of the brush is perpendicular to the tangent line at the tangent point in contact with the inner surface of the metal pipe. Thus, the abrasive agent 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 whose inner surface is mirror finished can be formed.

In the metal pipe inner surface grinding apparatus of the present application, it is preferable that the driving unit rotates the rotating body around the shaft and moves the rotating body along the shaft.

The driving unit rotates the rotating body around the shaft and moves the rotating body along the shaft, thereby grinding the inner surface of the metal pipe longer than the rotating body.

In the metal pipe inner surface polishing apparatus of the present application, it is preferable that the plurality of rotating bodies are connected in the axial direction thereof by a shaft body. Further, it is preferable that the interval between the rotating bodies adjacent in the axial direction is shorter than the length of the rotating body in the axial direction.

According to the above configuration, by connecting the plurality of rotating bodies according to the length of the metal pipe, even in the case of a long 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 same.

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

According to the above structure, the inner pressure is reliably applied to the inner surface of the metal pipe by the brush. Thus, the polishing agent disposed between the front end portion of the brush and the inner surface of the metal tube is reliably pressed against the inner surface of the metal tube.

The metal pipe of the present application has an arithmetic average roughness (Ra) of less than 0.1 μm on the inner surface polished by the inner surface polishing apparatus. The above-mentioned inner surface polishing apparatus can obtain a metal pipe having a mirror finished inner surface.

The metal tube of the present application has an inner surface polished by the inner surface polishing device and a length of 4m or more. The inner surface polishing apparatus can obtain a long metal pipe with a mirror-finished inner surface.

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

Effects of the application

In the present application, the dimension between the shaft of the rotating body and the front end of the brush is half or more of the inner diameter of the metal pipe, and the inner elastic body is elastically displaced. Thus, when the rotor is inserted into the inner side of the metal pipe, the inner elastic body that is elastically displaced by the inward movement of the brush elastically presses the brush radially outward. Thus, the tip end portion of the brush pressed radially outward abuts against the inner surface of the metal tube in a raised state, and 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 front end portion of the brush is kept in a standing state, and the polishing liquid is pressed against the inner surface of the metal pipe, so that the polishing agent adheres to the inner surface of the metal pipe. The brush applies internal pressure to the metal tube by the abrasive and the rotating body rotates around the shaft, whereby the abrasive attached to the inner surface of the metal tube abrades the inner surface of the metal tube in the circumferential direction. Thereby, a metal pipe with a mirror finished inner surface can be formed. In addition, dust generated when the inner surface of the metal pipe is polished is mixed into the polishing liquid, so that 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 same. On the other hand, if the inner surface of the metal tube is ground using the rasp, there is a problem in that the worn rasp is replaced with a new rasp. However, since the abrasive grinds the inner surface of the metal pipe, the rotating body itself is not worn. Therefore, the trouble of replacing the rotation body with a new one can be omitted, and thus the grinding time can be shortened as compared with the case of using the file.

Drawings

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

Fig. 2 is an enlarged partial top view showing a plurality of jigs connected by a shaft body.

Fig. 3 is a cross-sectional view of the clamp taken along line A-A of fig. 2.

Fig. 4 is a cross-sectional view of a metal tube.

Fig. 5 is a schematic cross-sectional view showing an inner surface polishing apparatus disposed midway in a metal pipe.

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

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

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

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

Fig. 10 is a partial enlarged sectional view showing a front end portion of the brush of fig. 9.

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

Fig. 12 is an enlarged partial cross-sectional view of the clamp of fig. 11.

Detailed Description

Hereinafter, embodiments of the present application 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 a long metal pipe (material to be polished) having a length of 4 m. Here, a case where the metal pipe is a stainless steel pipe is exemplified. In the present embodiment and examples and comparative examples described later, the "stainless steel pipe" is a pipe made of stainless steel, a tubular 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 a manufacturing apparatus of foods or medicines, but the use is not particularly limited. The arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe polished by the inner surface polishing apparatus 10 is less than 0.1 μm.

The inner surface polishing apparatus 10 is not limited to stainless steel pipes, and may be used for polishing inner surfaces of pipes, tubular members, or pipes made of metal other than stainless steel such as titanium and brass. In the present embodiment, the long stainless steel pipe having a length of 4m is polished, but the length of the polished metal pipe 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 or the like 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 into a liquid. Therefore, the inner surface polishing apparatus 10 is covered with a box-shaped cover (not shown) in order to prevent the liquid from leaking to the outside, but the cover is omitted here for convenience of explanation.

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 unit) 12 (see fig. 6) that is a supply unit 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) which is a rotating body that rotates inside the stainless steel pipe 1; and a motor (driving unit) 30 (see fig. 1 and 6) as a driving unit for driving the clamp 21 to rotate around the shaft 23.

As shown in fig. 6, the pump 12 is in communication with a tank 13 that stores the polishing liquid. The polishing liquid in the tank 13 is discharged from the front end 14 of the pump 12. In a state where the stainless steel pipe 1 is disposed in the inner surface polishing apparatus 10, the front end 14 of the pump 12 is connected to an end opening of the stainless steel pipe 1 on the opposite side of 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 motor 30 side end opening of the stainless steel pipe 1. The discharged polishing liquid flows to the recoverer 16 disposed below the stainless steel pipe 1 and the jig 21 (see fig. 1), and is stored in the drain pan 17. The recoverer 16 is integrally formed 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, an oil, ethanol or nitric acid. The material of the liquid is not particularly limited as long as it is a liquid that can be used for polishing of metals by mixing with a polishing agent.

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

The inner surface of the stainless steel pipe 1 is polished by pressing the polishing agent against the inner surface of the stainless steel pipe 1 by a jig 21 (see fig. 1). The inner surface polishing apparatus 10 of the present embodiment has 8 jigs 21, and these jigs 21 are connected to each other in the shaft 23 direction by a shaft body 22. That is, the inner surface of the 4m stainless steel pipe 1 (see fig. 6) was polished using 8 jigs 21. For convenience of explanation, in the following explanation, 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 of the clamp unit 20 on the motor 30 side (one end portion of the shaft body 22) is rotatably supported by the motor 30. The other end portion (the other end portion of the shaft body 22) of the clamp unit 20 on the opposite side from the motor 30 is supported by a support foot 33c provided upright 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, arranged between the motor 30 and the support legs 33c at predetermined intervals. The distal end portion of the support leg 33c is supported by the grip shaft 22, and by opening and closing the distal end portion, the support of the clamp unit 20 and the release of the support can be performed. When the stainless steel pipe 1 is moved from the other end portion to one end portion of the clamp unit 20 while the clamp unit 20 is covered with the stainless steel pipe 1, the support leg 33c releases the support of the clamp unit 20.

Fig. 2 is a partially enlarged plan view showing 3 jigs 21 on the other end side of the jig unit 20, which are arranged apart from the motor 30. The jig unit 20 has 8 jigs 21, but here, as a representative, only 3 jigs 21 are shown. Each of the 8 jigs 21 is the same shape, and the length dimension of the jig 21 is L1. Adjacent jigs 21 are arranged at equal intervals of L2. The gap L2 between the jigs 21 and 21 is shorter than the length L1 of the jigs 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 clamp 21 in a direction orthogonal to the axis 23. The jig 21 is fixed to the shaft 22 and rotates together with the shaft 22. The jig 21 has: a main body 41 extending in the direction of the shaft 23; a brush 44 that protrudes radially outward from the main body 41 and is disposed radially outward so as to be orthogonal to the shaft 23, and is movable in the radial direction; and a tube (inner elastic body) 45 as an inner elastic body disposed between the shaft 23 and the brush 44 to elastically press the brush 44 radially outward.

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

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

Brush 44 is supported radially movably on a side wall 48a of brush holder 48. The brush 44 is disposed radially outward of the tube 45 and extends straight parallel to 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 by 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) of half the inner diameter of the stainless steel pipe 1. Further, the brush 44 and its front end portion standing up means that the brush 44 and its front end portion stand up, and does not include the case where the brush 44 and its front end portion are bent or folded.

The inner elastic member is a tube 45 made of resin and has elasticity. The tube 45 is disposed between the shaft 23 and the brush 44 in the brush holder 48, that is, at a position 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 elastically displaces. Tube 45 is in contact with brush 44 and presses brush 44 directly radially outward. 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 in the entire longitudinal direction of the brush 44.

Returning to fig. 1, the motor 30 rotates the clamp 21 about the shaft 23 and moves the clamp 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 shaft 23 direction on a pair of guide rails 31. The pair of guide rails 31 are arranged side by side in the horizontal direction and fix a support plate 34, and the support plate 34 is mounted on a support leg 33a and a support leg 33b provided upright 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 substrate 32, and rotates the pinion 37 via the shaft 36. The motor 30 moves along the shaft 23 together with the base plate 32 by rotating the pinion 37 engaged with the racks 38 mounted on the support legs 33a and 33b.

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 (see fig. 7) so as to cover the jig 21 from the other end to one end of the jig unit 20, and is positioned. Fig. 8 is a partially enlarged plan view of the other end portion of the jig unit 20 showing a state in which the stainless steel pipe 1 is positioned. When the stainless steel pipe 1 is fixed in position, all the jigs 21 are disposed inside the stainless steel pipe 1. When the stainless steel pipe 1 is positioned, an end opening of the stainless steel pipe 1 opposite to the motor 30 is connected to the front end 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, the dimension L3 between the tip of the brush 44 and the shaft 23 is larger than the dimension L4 of 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. As a result, the brush 44 is elastically pressed radially outward by the tube 45, and thus the tip end portion of the brush 44 abuts against the inner surface of the stainless steel tube 1 in the raised state, and a constant internal pressure is applied. At this time, as shown in fig. 10, the tip of at least a part of the brush 44 is vertically abutted 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 tip 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 tip portion of the brush 44 is preferably 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, brush 44 tends to bend and be difficult to stand up.

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 the polishing liquid spreads from one end to the other end of the stainless steel pipe 1. In this state, when the motor 30 rotates the jig 21 around the shaft 23, the polishing liquid moves toward the tip end portion of the brush 44 by centrifugal force and is accumulated. The polishing liquid is pressed against the inner surface of the stainless steel pipe 1 by the tip portion of the brush 44, 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 radially outward, the brush 44 and the tip end portion thereof are kept in the standing state during rotation of the jig 21 (see fig. 12). In this way, the brush 44 applies internal pressure to the stainless steel pipe 1 by the abrasive 2 and rotates around the shaft 23, so that the abrasive 2 attached to the inner surface of the stainless steel pipe 1 abrades 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 displaced (compressed) inward Fang Danxing. The tube 45 elastically displaced inward elastically presses the brush 44 radially outward. Thus, the tube 45 abuts against the inner surface of the metal tube in a raised state at the tip end portion of the brush 44 pressed radially outward, and internal pressure is applied. When the jig 21 is rotated by supplying the polishing liquid into the stainless steel pipe 1, the tip end portion of the brush 44 is rotated while being held in the raised state. At this time, the front end portion of the brush 44 presses the attached abrasive against the inner surface of the stainless steel pipe 1, whereby the abrasive abrades the inner surface in the circumferential direction. That is, the present application relates to an apparatus for polishing an inner surface of a metal pipe using only physical polishing.

The motor 30 rotates the clamp 21 about the axis and moves the clamp 21 along the axis 23. Since the adjacent jigs 21 are arranged at equal intervals, the motor 30 moves the jigs 21 by the amount of the interval L2 between the jigs 21 and the jigs 21 in the shaft 23 direction. 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 jigs 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 miniaturized and the power consumption can be reduced, as compared with the case where 1 jig extending in the entire longitudinal direction of the stainless steel pipe 1 is used. In addition, the reaction force applied from the inner surface of the stainless steel pipe 1 can be suppressed, and breakage of the clamp unit 20 can be prevented.

[ characteristics of the inner surface polishing apparatus according to the present embodiment ]

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

In the inner 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 greater than half the dimension L4 of the inner diameter 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 end portion of the brush 44 pressed radially outward is brought into contact with the inner surface of the stainless steel pipe 1 in a raised state, and an internal pressure is applied. Therefore, when the jig 21 disposed inside the stainless steel pipe 1 is rotated in a state where the polishing liquid is supplied, the tip 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 abrasive and the jig 21 rotates around the shaft 23, whereby the abrasive 2 attached to the inner surface of the stainless steel pipe 1 abrades the inner surface of the stainless steel pipe 1 in the circumferential direction. Thereby, the stainless steel pipe 1 having the mirror-finished inner surface can be formed.

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, scattering of dust into the atmosphere can be prevented. In addition, 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 tube is ground using the rasp, there is a problem in that the worn rasp is replaced with a new rasp. However, in the present application, since the abrasive 2 abrades the inner surface of the stainless steel pipe 1, the jig 21 itself is not worn. Therefore, the trouble of replacing the new jig 21 can be omitted, and the polishing time can be shortened.

In the inner surface polishing apparatus 10 of the present embodiment, the tip end portion of the brush 44 preferably contacts the inner surface of the metal pipe in a raised state, and an internal pressure of 80N or more is applied. In the inner 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 becomes weak, and polishing tends to be difficult, but this tendency can be suppressed. On the other hand, when the internal pressure is more than 300N, the brush 44 tends to bend and be difficult to stand up, but this can be suppressed.

In the inner 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, the plurality of brushes 44 are arranged at equal intervals in the circumferential direction of the main body, and therefore the inner pressure applied by the tips of the plurality of brushes 44 in contact with 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 in which the jig 21 is disposed inside the stainless steel pipe 1, the vertical abutment of the distal end portion of the brush 44 with the inner surface of the stainless steel pipe 1 means that the distal end portion of the brush 44 abuts with the inner surface of the stainless steel pipe 1 in a standing state to apply an internal pressure. In this state, the brush 44 applies internal pressure to the stainless steel pipe 1 by the abrasive 2 and the jig 21 rotates around the shaft 23, whereby the abrasive 2 attached to the inner surface of the stainless steel pipe 1 abrades the inner surface of the stainless steel pipe 1 in the circumferential direction. Therefore, the stainless steel pipe 1 whose inner surface is mirror finished can be formed.

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

In the inner 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, even the stainless steel pipe 1 longer than the jig 21 can be polished over its entire inner surface.

In the inner surface polishing apparatus 10 of the present embodiment, the jig 21 is connected to the shaft body 22 in the direction of the shaft 23. By connecting the plurality of jigs 21 according to the length of the metal pipe, even in the case of a long metal pipe having a length of, for example, 4m or more, the plurality of jigs 21 can press the polishing agent 2 against the inner surface of the metal pipe and polish the same.

< example >

The inventors of the present application measured the arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing apparatus 10, and compared the arithmetic average 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 a stainless steel pipe polished by conventional longitudinal polishing, as a comparative example. In the longitudinal polishing, the inner surface of the stainless steel tube was polished in a total of 5 steps using a file having a particle size of 90 in step 1, a file having a particle size of 120 in step 2, a file having a particle size of 140 in step 3, a file having a particle size of 240 in step 4, and a file having a particle size of 400 in step 5. The particle size of the rasp is based on JIS standard "regulation of particle size of an abrasive for polishing cloth paper according to JISR 6010". Among the plurality of stainless steel pipes polished by such longitudinal polishing, when the arithmetic average roughness (Ra) in the circumferential direction was measured for any 2, the 1 st was 0.7576 μm and the 2 nd was 0.6103 μm.

< Table 2>

Table 2 shows graphs for measuring the arithmetic average roughness (Ra) in the circumferential direction of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing apparatus 10 of the present application. 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 timing, in step 1, when the measuring brush 44 presses the inner pressure of the inner surface of the stainless steel pipe 1, the inner pressure is 120N to 160N. In the next step 2, a brush 44 having a wire diameter of 0.4mm was used, and the jig 21 was rotated at 300rpm for 30 minutes. At any timing, in step 2, when the measuring brush 44 presses the inner pressure of the inner surface of the stainless steel pipe 1, the inner pressure is 160N or more and 270N or less. When the arithmetic average 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. From the above, the arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe 1 of the present application is less than 0.1 μm. The arithmetic average roughness (Ra) is defined by JISB 0031 (1994).

The embodiments of the present application have been described above with reference to the drawings, but the specific configuration is not limited to these embodiments. The scope of the present application is expressed not only by the description of the above embodiments but also by the claims, and also includes all modifications within the meaning and scope equivalent to the claims.

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 not limited thereto. 1 clamp of the same length as the stainless steel tube can also be used. At this time, the motor 30 and the clamp 21 may not be moved in the direction of the shaft 23 (see fig. 1, etc.). The number of jigs is not limited to 8, and a plurality of jigs such as 2 or 3 jigs 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 jigs 21, but the present application 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 polish 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 of the inner diameter of the stainless steel pipe 1, but the dimension L3 and the dimension L4 may be equal.

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

In the above embodiment, as shown in fig. 3, the base portion 44a of the brush 44 is disposed inside the brush holder 48, 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 resin (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 44a of the brush 44 is arranged radially outside the tube 45, and the tube 45 directly presses the base 44a of the brush 44. However, other members may be disposed between the tube 45 and the brush 44.

In the above embodiment, as shown in fig. 3, the brushes 44 and the brush holders 48 supporting the brushes 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 be disposed 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 disposed at 1, 2, or 4 or more positions in the circumferential direction of the jig 21. The brush 44 and the tube 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 agent

10. Inner surface grinding device

12. Pump (supply unit)

21. Cramp (rotating body)

22. Shaft body

23. Shaft

30. Motor (drive unit)

41. Main body

44. Brush with brush body

45. Tube (inner elastic body)

S space

Claims

1. An apparatus for polishing an inner surface of a metal pipe, which is 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, which is a mixture of a granular polishing agent and a liquid, to the inside of the metal pipe,

the rotating body has a brush protruding in a radial direction perpendicular to the shaft and having elasticity, 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,

the inner elastic body presses the brush radially outward in a state where the rotating body is disposed inside the metal pipe, whereby a tip end portion of the brush is brought into contact with the inner surface of the metal pipe in a standing state, and an inner pressure of 80N or more 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 polished by the tip end portion of the brush being pressed.

2. The apparatus according to claim 1, wherein the brush has a tip portion that abuts against the inner surface of the metal pipe in a raised 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.

3. The apparatus for polishing an inner surface of a metal pipe according to claim 1, wherein,

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

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

4. An inner surface grinding apparatus for a metal pipe according to claim 3,

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

the side walls support the brush and enable it to move radially.

5. The apparatus for polishing an inner surface of a metal pipe according to any one of claim 1 to 4, wherein,

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

the brush is arranged radially outside the body,

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

6. The apparatus for polishing an inner surface of a metal pipe according to any one of claim 1 to 4, wherein,

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

the inner elastic body is disposed radially inward of the brush along an axial direction of the rotating body.

7. The apparatus for polishing an inner surface of a metal pipe according to any one of claim 1 to 4, wherein,

the rotating body has a plurality of the brushes,

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

spaces are formed between 2 brushes adjacent in the radial direction of the rotating body.

8. The apparatus for polishing an inner surface of a metal pipe according to any one of claims 1 to 4, wherein a plurality of the brushes are arranged at equal intervals in a circumferential direction of the rotating body.

9. The apparatus for polishing an inner surface of a metal pipe according to claim 3 or 4, wherein,

the rotating body is provided with a plurality of the brushes and a plurality of the brush holders,

a plurality of brush holders respectively supporting a plurality of brushes,

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

10. The apparatus according to any one of claims 1 to 4, wherein in a state in which the rotating body is provided inside the metal pipe, when the front end portion of the brush abuts against the inner surface of the metal pipe, at least a part of the front end portion of the brush is perpendicular to a tangent line at a tangent point abutting against the inner surface of the metal pipe.

11. The apparatus according to any one of claims 1 to 4, wherein the driving unit rotates the rotating body around the shaft and moves the rotating body along the shaft.

12. The apparatus for grinding the inner surface of a metal pipe according to any one of claims 1 to 4, wherein a plurality of the rotating bodies are connected by a shaft body in the axial direction thereof.

13. The apparatus according to claim 12, wherein the interval between the rotating bodies adjacent in the axial direction is shorter than the length of the rotating bodies in the axial direction.

14. The apparatus according to any one of claims 1 to 4, wherein the inner elastic body is compressed in a state where the rotating body is provided inside the metal pipe, and the inner elastic body elastically presses the brush radially outward.