JP6663067B1 - Metal pipe inner surface polishing equipment - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a metal pipe inner surface polishing apparatus capable of forming a metal pipe having an inner surface mirror-finished, and a metal pipe having an inner surface polished by using the same. A rotating body (21) includes a brush (44) having elasticity and provided in a radial direction and orthogonal to a shaft (23) and provided outside in a radial direction, and an inner elastic body (46) provided inside in the radial direction with respect to the brush (44). However, when the size between the shaft 23 and the tip of the brush 44 is more than half the inner diameter of the metal pipe 1 and the rotating body 21 is installed inside the metal pipe 1, the inner elastic body 46 moves the brush 44 Is pressed radially outwardly, the tip of the brush 44 abuts against the inner surface of the metal pipe 1 while standing upright, and internal pressure is applied, so that the polishing agent supplied from the supply means 12 and adhered to the inner surface of the metal pipe 1 Is pressed against the inner surface of the metal pipe 1 to polish the inner surface. [Selection diagram] FIG.

Description

The present invention relates to an inner surface polishing equipment for metal pipe.

  Conventionally, in the case of polishing the inner surface of a metal pipe, there is known a method in which a ground treatment is performed with a polishing material having a smaller number and then the inner surface is finish-polished with a polishing material having a larger number. 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 polishing belt is moved in the longitudinal direction of the metal pipe to polish the inner surface of the metal pipe. Have been.

JP-A-11-188594

  However, the vertical polishing described in Patent Document 1 has a problem that the surface of the inner surface of the metal pipe after polishing is rough. Therefore, it is not preferable for a pipe used in, for example, a pharmaceutical or food manufacturing facility, and an inner metal pipe having a smaller surface roughness is desired.

  Further, in the vertical polishing described in Patent Document 1, there is a problem that dust generated when polishing the inner surface of the metal pipe is scattered in the air, and the polishing time is long because a worn polishing belt is replaced with a new polishing belt. is there.

Accordingly, the present invention has been made to solve the above problems, and an object thereof is to provide an inner surface polishing equipment for metal pipe capable of forming a metal pipe whose inner surface is mirror finished.

The invention further dust generated when the polishing is prevented from scattering to the atmosphere, and to provide an inner surface polishing equipment for metal pipe capable of shortening the polishing time in comparison with conventional vertical polishing.

  An inner surface polishing apparatus for a metal pipe according to the present invention is an inner surface polishing apparatus for a metal pipe for polishing an inner surface of a metal pipe which is a material to be polished, and a rotating body extending in an axial direction, and the rotating body being rotated around the axis. Driving means for rotating, and a supply means for supplying a polishing liquid in which a particulate abrasive and a liquid are mixed to the inside of the metal pipe, wherein the rotating body protrudes in a radial direction orthogonal to the axis, and A brush having elasticity provided radially outward, and an inner elastic body provided radially inward from the brush, wherein a dimension between the shaft and a tip of the brush is an inner diameter of the metal pipe. In the state where the rotating body is installed inside the metal pipe, the inner elastic body presses the brush radially outward, and the metal pipe is kept upright with the tip of the brush standing. Abut against the inner surface to increase the internal pressure By loading the abrasive adhering to the inner surface of the metal pipe supplied from said supply means it is pressed against the inner surface of the metal pipe, polishing the inner surface.

  In the apparatus for polishing an inner surface of a metal pipe according to the present invention, the rotating body is provided so as to protrude outward from the main body in a radial direction perpendicular to the axis and the main body extending in the axial direction, and to be movable in the radial direction. Preferably, the brush includes the brush and the inner elastic body, which is provided between the shaft and the brush and elastically presses the brush radially outward.

  With this configuration, the inner elastic body elastically presses the brush radially outward. With this, when the rotating body is inserted into the metal pipe, the inner elastic body elastically displaced inward in the radial direction presses the brush radially outward, and the brush comes into contact with the inner surface of the metal pipe while the tip of the brush stands upright. Internal pressure can be applied. In addition, the inner elastic body elastically presses the brush radially outward to prevent the brush from bending when the rotating body is rotated in the metal pipe, and the brush tip is in an upright state. The inner surface of the metal pipe can be polished while maintaining the condition.

  In the apparatus for polishing an inner surface of a metal pipe according to the present invention, the brush and the inner elastic body may come into contact with each other, and the inner elastic body may directly press the brush radially outward.

  In the above configuration, the brush and the inner elastic body come into contact with each other, and the inner elastic body directly presses the brush radially outward, so that the inner elastic body can surely press the brush.

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

  Since the plurality of brushes are provided at equal intervals in the circumferential direction of the main body, the internal pressure applied by the tips of the plurality of brushes coming into contact with the inner surface of the metal pipe can be made uniform.

  In the metal pipe inner surface polishing apparatus according to the present invention, it is preferable that a tip of the brush abuts perpendicularly to an inner surface of the metal pipe in a state where the rotating body is installed inside the metal pipe.

  When the rotating body is installed inside the metal pipe and the tip of the brush abuts vertically on the inner surface of the metal pipe, it is possible to apply the internal pressure by abutting the inner face of the metal pipe with the tip of the brush standing upright. Means to do. In this state, the rotating body rotates around the axis while the brush applies internal pressure to the metal pipe via the abrasive, so that the abrasive attached to the inner surface of the metal pipe polishes the inner surface of the metal pipe in the circumferential direction. I do. Therefore, a metal pipe whose inner surface is mirror-finished can be formed.

  In the metal pipe inner surface polishing apparatus according to the present invention, a space may be formed between the inner surface of the metal pipe and the surface of the rotating body while the rotating body is installed inside the metal pipe. preferable.

  The polishing liquid is injected from one end of the metal pipe to the other end while the rotating body is installed inside the metal pipe. Since the space is formed between the inner surface of the metal pipe and the surface of the rotating body, the polishing liquid injected into the metal pipe can pass from one end to the other end of the metal pipe through the space.

  In the metal pipe inner surface polishing apparatus according to the present invention, it is preferable that the driving unit moves the rotator along the axis while rotating the rotator about the axis.

  The driving means moves the rotating body along the axis while rotating the rotating body about the axis, so that the inner surface of even a metal pipe longer than the rotating body can be polished.

  In the apparatus for polishing the inner surface of a metal pipe according to the present invention, it is preferable that the plurality of rotating bodies are connected via a shaft in the axial direction.

  According to the above configuration, by connecting a plurality of rotating bodies according to the length of the metal pipe, even if the length is a long metal pipe having a length of, for example, 4 m or more, the plurality of rotating bodies apply abrasive to the metal pipe. Can be polished by pressing against the inner surface.

  In the metal pipe according to the present invention, the arithmetic mean roughness (Ra) of the inner surface polished by the inner surface polishing device is less than 0.1 μm. Thus, a metal pipe whose inner surface is mirror-finished can be obtained.

  The inner surface of the metal pipe according to the present invention is polished by the above inner surface polishing apparatus, and has a length of 4 m or more. This makes it possible to obtain a long metal pipe whose inner surface is mirror-finished.

  In the present invention, the dimension between the shaft of the rotating body and the tip of the brush is at least half the inner diameter of the metal pipe, and the inner elastic body is elastically displaced. Thus, when the rotating body is inserted into the metal pipe, the inner elastic body elastically displaced by the brush moving inward elastically presses the brush radially outward. Thus, the inner pressure is applied by contacting the inner surface of the metal pipe with the tip of the brush pressed radially outwardly standing upright. Then, when the rotating body installed inside the metal pipe is rotated while the polishing liquid is supplied, the polishing liquid is pressed against the inner surface of the metal pipe while the tip of the brush is maintained in an upright state, and Abrasive is attached to the inner surface. When the rotating body rotates around the axis while the brush applies internal pressure to the metal pipe via the abrasive, the abrasive attached to the inner surface of the metal pipe polishes the inner surface of the metal pipe in the circumferential direction. Thereby, a metal pipe whose inner surface is mirror-finished can be formed. Further, dust generated when polishing the inner surface of the metal pipe is mixed into the polishing liquid, so that it is possible to prevent the dust from scattering into the atmosphere. Further, the frictional heat generated by the abrasive polishing the inner surface of the metal pipe can be absorbed by the liquid and cooled. On the other hand, if the inner surface of the metal pipe is polished with a file, it takes time to replace the worn file with a new file. However, since the abrasive grinds the inner surface of the metal pipe, the rotating body itself does not wear. Therefore, it is not necessary to replace the rotating body with a new one, so that the polishing time can be reduced as compared with the case where a file is used.

1 is a schematic cross-sectional view of a metal pipe inner surface polishing apparatus according to an embodiment of the present invention. FIG. 5 is a partially enlarged top view showing a plurality of jigs connected via a shaft. FIG. 3 is a sectional view of the jig taken along line AA of FIG. 2. It is sectional drawing of a metal pipe. It is a schematic sectional drawing which shows the inner surface polishing apparatus in the middle of installing a metal pipe. It is a schematic sectional drawing which shows the inner surface polishing apparatus which fixed and installed the metal pipe. It is a partial enlarged top view in the middle of moving a metal pipe from the other end of a jig unit toward one end. It is a partial enlarged top view of the other end part of the jig unit which shows the state which positioned the metal pipe. It is an expanded sectional view showing a part of jig inserted in the inside of a metal pipe. FIG. 10 is a partially enlarged cross-sectional view illustrating a brush tip portion of FIG. 9. FIG. 9 is a cross-sectional view taken along the line BB of FIG. 8 in a state in which a polishing liquid is supplied into the metal pipe and the jig is rotated. FIG. 12 is a partially enlarged sectional view of the jig of FIG. 11.

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

  The inner surface polishing apparatus 10 of the present embodiment shown in FIG. 1 polishes the inner surface of a long stainless steel pipe (metal pipe which is a material to be polished) having a length of 4 m. The stainless steel pipe whose inner surface is polished by the inner surface polishing device 10 is used for a food or chemical manufacturing device, but the use is not particularly limited. The arithmetic average roughness (Ra) of the inner surface of the stainless pipe polished by the inner surface polishing device 10 is less than 0.1 μm.

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

  The inner surface polishing apparatus 10 polishes the inner surface of the stainless steel pipe using a wet abrasive mixed in a liquid, as described later. Therefore, in order to prevent the liquid from leaking to the outside, the inner surface polishing apparatus 10 is covered with a box-shaped cover (not shown), but the cover is omitted here for convenience of explanation.

  Referring also to FIG. 6, the inner surface polishing apparatus 10 includes a pump 12 serving as a supply unit that supplies a polishing liquid to the inside of the stainless steel pipe 1 in a state where the stainless steel pipe 1 is installed and fixed, and A jig 21 is a rotating body that rotates inside, and a motor 30 is a driving unit that drives the jig 21 to rotate around an axis 23.

  The pump 12 communicates with a tank 13 for storing the polishing liquid, and discharges the polishing liquid in the tank 13 from a tip 14. With the stainless steel pipe 1 installed in the inner surface polishing apparatus 10, the tip 14 of the pump 12 is connected to the end opening of the stainless steel pipe 1 opposite to the motor 30 via a pipe (not shown). The pump 12 discharges and supplies the polishing liquid into the stainless steel pipe 1 while the stainless steel pipe 1 is installed and operated in the inner surface polishing apparatus 10. 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 polishing liquid is guided to the recovery device 16 installed below the stainless steel pipe 1 (the jig 21), and is stored in the drain van 17. The collector 16 is formed integrally with a cover (not shown).

  The polishing liquid is a mixed liquid of a liquid and a granular abrasive. As the liquid, water is used in the present embodiment, but the liquid is not limited to this. The liquid may be acidic water or an organic solvent, specifically alcohol, oil, ethanol or nitric acid. However, the material of the liquid is not particularly limited as long as the liquid is used for polishing a metal by mixing an abrasive.

  In this embodiment, aluminum oxide is used as the abrasive, but the abrasive is not limited to this. Any wet abrasive may be used as the abrasive, as long as it has a higher specific gravity than water and a higher hardness than the metal to be polished. For example, carbide or oxide is used as such an abrasive, and specifically, carbon or diamond can be used. However, the material of the abrasive is not particularly limited as long as the abrasive is used for polishing metal by mixing with a liquid.

  The abrasive is pressed against the inner surface of the stainless steel pipe 1 by the jig 21 to polish the inner surface of the stainless steel pipe 1. The inner surface polishing apparatus 10 of the present embodiment has eight jigs 21, and these jigs 21 are connected via a shaft 22 in the direction of the axis 23. That is, the inner surface of the 4 m stainless steel pipe 1 is polished using eight jigs 21. For convenience of description, the eight jigs 21 and the shaft 22 will be collectively referred to as a jig unit 20 in the following description.

  As shown in FIG. 1, one end of the jig unit 20 on the motor 30 side (one end of the shaft 22) is rotatably supported by the motor 30. The other end of the jig unit 20 opposite to the motor 30 (the other end of the shaft 22) is supported by support legs 33c standing on the ground. In the jig unit 20, a portion of the shaft 22 is supported by a plurality of support legs (not shown) arranged at predetermined intervals between the motor 30 and the support legs 33c. The tip of the support leg 33c is supported by sandwiching the shaft 22, and the jig unit 20 can be supported and released by opening and closing the tip. When the stainless steel pipe 1 is moved from the other end to the one end of the jig unit 20 while covering the jig unit 20, the support leg 33c releases the support of the jig unit 20.

  FIG. 2 is a partially enlarged top view showing three jigs 21 on the other end side which are arranged apart from the motor 30 in the jig unit 20. The jig unit 20 has eight jigs 21, but here, only three jigs 21 are shown as a representative. Each of the eight jigs 21 has the same shape, and the length of the jig 21 is L1. Adjacent jigs 21 are arranged at equal intervals L2. The distance L2 between the jigs 21 is shorter than the length L1 of the jig 21.

  FIG. 3 is a cross-sectional view taken along line AA 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 a shaft 22 and rotates together with the shaft 22. The jig 21 includes a main body 41 extending in the direction of the shaft 23, a brush 44 protruding outward from the main body 41 in a radial direction orthogonal to the shaft 23, and provided movably in the radial direction, a shaft 23 and the brush 44. And a tube 45 which is an inner elastic body for elastically pressing the brush 44 radially outward.

  The main body 41 has a cylindrical cross section orthogonal to the shaft 23, and has three brush receivers 48 with concave cross sections at equal intervals in the circumferential direction of the main body 41. The brush receiver 48 is provided with a brush 44 and a tube 45.

  The brush 44 is made of countless resins extending linearly, and has elasticity. Here, the brush 44 is a concept including a base 44a in which countless resins are implanted. Each resin constituting the brush 44 of the present embodiment has a circular cross section in a direction perpendicular to the direction in which it extends, and has a diameter (hereinafter, referred to as a wire diameter) of 0.2 mm to 0.6 mm. The wire diameter of the brush 44 is not particularly limited as long as the brush 44 can maintain the upright state when the jig 21 inserted inside the stainless steel pipe 1 rotates.

  The brush 44 is supported on a side wall 48a of the brush receiver 48 so as to be movable in the radial direction. The brush 44 is disposed radially outside the tube 45 and extends straight parallel to the shaft 23. In the present embodiment, three brushes 44 are provided at equal intervals in the circumferential direction of the main body 41. Note that the number of brushes 44 is not limited to three. The brush 44 supported by the brush receiver 48 projects from the main body 41 in a direction (radial direction) perpendicular to the shaft 23 and stands up along the radial direction. The brush 44 is elastically pressed outward in the radial direction by the tube 45, and is engaged with a stopper (not shown) provided on the brush receiver 48, so that the support state of the brush receiver 48 is maintained. You. A dimension L3 between the tip of the brush 44 and the shaft 23 is larger than a dimension L4 (see FIG. 4) which is a half of the inner diameter of the stainless steel pipe 1. Note that raising the brush 44 and its tip means that the brush 44 and its tip rise, and does not include bending and bending of the brush 44 and its tip.

  The inner elastic member is a resin tube 45 having elasticity. The tube 45 is arranged inside the brush receiver 48 between the shaft 23 and the brush 44, that is, radially inside the brush 44. The tube 45 provided inside the brush receiver 48 is disposed between the bottom wall 48b of the brush receiver 48 and the brush 44, and is elastically displaced. The tube 45 contacts the brush 44 and presses the brush 44 directly radially outward.

  Returning to FIG. 1, the motor 30 moves the jig 21 along the shaft 23 while rotating the jig 21 around the shaft 23. The motor 30 is fixed on a substrate 32 movably mounted on the pair of rails 31 in the direction of the shaft 23. The pair of rails 31 are arranged side by side in the horizontal direction, and are fixed to a support leg 33a erected on the ground and a support plate 34 attached to the support leg 33b.

  The board 32 is driven along a shaft 23 by a rack and pinion. A motor (not shown) is mounted on the substrate 32, and the motor rotates a pinion gear 37 via a shaft 36. The rotation of the pinion gear 37 that meshes with the rack gear 38 attached to the support leg 33a and the support leg 33b causes the motor 30 to move along with the substrate 32 along the shaft 23.

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

  FIG. 5 is a schematic sectional view showing the inner surface polishing apparatus 10 during installation of the stainless steel pipe 1. 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), and is positioned. FIG. 8 is a partially enlarged top view of the other end of the jig unit 20 showing the state where the stainless steel pipe 1 is positioned. When the stainless steel pipe 1 is positioned and fixed, all the jigs 21 are installed inside the stainless steel pipe 1. When the stainless steel pipe 1 is positioned, the end opening of the stainless steel pipe 1 opposite to the motor 30 is connected to the tip 14 of the pump 12 via a pipe (not shown), and the polishing liquid in the tank 13 is supplied to the stainless steel pipe 1. It becomes possible to supply inside.

  A dimension L3 between the tip of the brush 44 and the shaft 23 is larger than a dimension L4 which is a half of 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 inward in the radial direction, and the tube 45 is compressed. As a result, the tube 45 elastically presses the brush 44 radially outward, so that the tip of the tube 44 abuts against the inner surface of the stainless steel pipe 1 and applies a constant internal pressure while the brush 44 is standing. At this time, as shown in FIG. 10, at least a part of the tip of the brush 44 is in vertical contact with 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 of the brush 44 is set to 80N to 300N. If the internal pressure is smaller than 80 N, the force of the tip of the brush 44 pressing the abrasive against the inner surface of the stainless steel pipe 1 is weakened, and the polishing cannot be performed. On the other hand, if the internal pressure is greater than 300 N, the brush 44 will bend and will not stand.

  When the polishing liquid is supplied from the tank 13 into 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. Spread from one end to the other. In this state, when the motor 30 rotates the jig 21 around the shaft 23, the polishing liquid moves to the tip of the brush 44 by the centrifugal force and collects. Then, the tip of the brush 44 presses the polishing liquid against the inner surface of the stainless steel pipe 1, and the abrasive 2 adheres to the inner surface of the stainless steel pipe 1. Further, since the tube 45 elastically presses the brush 44 outward in the radial direction, the brush 44 and the distal end thereof maintain the upright state while the jig 21 is rotating (see FIG. 12). As described above, the brush 44 rotates around the shaft 23 while applying an internal pressure to the stainless steel pipe 1 via the abrasive 2, so that the abrasive 2 attached to the inner surface of the stainless steel pipe 1 circulates around the inner surface of the stainless steel pipe 1. Polish in the direction.

  As described above, in this embodiment, when the jig 21 is inserted into the stainless steel pipe 1, the tube 45 elastically displaced inward elastically presses the brush 44 radially outward. Thus, the inner pressure is applied by contacting the inner surface of the metal pipe with the tip of the brush pressed radially outwardly standing upright. Then, when the polishing liquid is supplied into the stainless steel pipe 1 and the jig 21 is rotated, the tip of the brush 44 rotates while maintaining the 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 so that the abrasive grinds the inner surface in the circumferential direction. That is, the present invention relates to an apparatus for polishing an inner surface of a metal pipe using only physical polishing.

  The motor 30 moves the jig 21 along the shaft 23 while rotating the jig 21 around the axis. Since the adjacent jigs 21 are arranged at equal intervals, the motor 30 moves the jigs 21 in the direction of the axis 23 by an interval L2 between the jigs 21. Thus, the entire inner surface of the stainless steel pipe 1 is polished by the jig 21 and the abrasive 2. By arranging the adjacent jigs 21 at an interval L2 in this manner, the jig 21 is more axially moved than when one jig extending in the entire longitudinal direction of the stainless steel pipe 1 is provided. The driving force for rotating around 23 can be suppressed, and the size and power consumption of the motor 30 can be reduced. Further, the reaction force received from the inner surface of the stainless steel pipe 1 can be suppressed, and the jig unit 20 can be prevented from being damaged.

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

  In the inner surface polishing apparatus 10 of the present embodiment, 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 dimension L4 of the inner diameter of the stainless steel pipe 1, and the tube 45 itself is elastically displaced. Thereby, when the jig 21 is inserted into the stainless steel pipe 1, the tube 45 elastically displaced inward presses the brush 44 radially outward. Then, while the tip of the brush 44 pressed outward in the radial direction is upright, the brush 44 comes into contact with the inner surface of the stainless steel pipe 1 to apply the internal pressure. Therefore, when the jig 21 installed inside the stainless steel pipe 1 is rotated while the polishing liquid is supplied, the tip of the brush 44 presses the polishing liquid against the inner surface of the stainless steel pipe 1, and the inner surface of the stainless steel pipe 1 is pressed. An abrasive can be attached to the surface. The jig 21 rotates around the axis 23 while the brush 44 applies an internal pressure to the stainless steel pipe 1 via the abrasive, so that the abrasive 2 attached to the inner surface of the stainless steel pipe 1 rotates around the inner surface of the stainless steel pipe 1. Polish in the direction. Thereby, 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, dust generated when polishing the inner surface of the stainless steel pipe 1 is mixed into the polishing liquid, so that it is possible to prevent the dust from scattering into the atmosphere. Further, the frictional heat generated by the polishing agent 2 polishing the inner surface of the stainless steel pipe 1 can be absorbed by the liquid and cooled. On the other hand, if the inner surface of the stainless steel pipe is polished with a file, it takes time to replace the worn file with a new file. However, in the present invention, since the abrasive 2 polishes the inner surface of the stainless steel pipe 1, the jig 21 itself does not wear. Therefore, the labor for replacing the jig 21 with a new one can be omitted, and the polishing time can be reduced.

  In the inner surface polishing apparatus 10 of the present embodiment, the tube 45 elastically presses the brush 44 radially outward. Thus, when the jig 21 is inserted into the stainless steel pipe 1, the tube 45 elastically displaced inward in the radial direction presses the brush 44 outward in the radial direction, and the inner surface of the stainless steel pipe 1 with the tip of the brush 44 standing upright. To apply an internal pressure. In addition, the tube 45 elastically presses the brush 44 radially outward to prevent the brush 44 from bending when the jig 21 is rotated in the stainless steel pipe 1, and the tip of the brush 44 The inner surface of the stainless steel pipe 1 can be polished while maintaining the standing state of the portion.

  In the inner surface polishing apparatus 10 of the present embodiment, the brush 45 and the tube 45 come into contact with each other, and the tube 45 directly presses the brush 44 radially outward, so that the tube 45 surely presses the brush 44. be able to.

  In the inner surface polishing apparatus 10 of the present embodiment, since the plurality of brushes 44 are provided at equal intervals in the circumferential direction of the main body, the tips of the plurality of brushes 44 abut against the inner surface of the stainless steel pipe 1 to uniformly reduce the internal pressure applied. can do.

  In the inner surface polishing apparatus 10 of the present embodiment, when the jig 21 is installed inside the stainless steel pipe 1, the tip of the brush 44 abuts vertically on the inner surface of the stainless steel pipe 1. Means that the inner pressure is applied to the inner surface of the stainless steel pipe 1 while standing. In this state, the jig 21 rotates around the axis 23 while the brush 44 applies an internal pressure to the stainless steel pipe 1 via the abrasive 2, so that the abrasive 2 attached to the inner surface of the stainless steel pipe 1 is removed. 1 is polished 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, a polishing liquid is injected from one end of the stainless steel pipe 1 to the other end with the jig 21 installed inside the stainless steel pipe 1. 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 spreads from one end to the other end of the stainless steel pipe 1 through the space S. Can be.

  In the inner surface polishing apparatus 10 of the present embodiment, the jig 21 is moved along the axis 23 while the motor 30 rotates the jig 21 around the axis 23. Thereby, even if the stainless steel pipe 1 is longer than the jig 21, the entire inner surface thereof can be polished.

  In the inner surface polishing apparatus 10 of the present embodiment, the jig 21 is connected via the shaft 22 in the axis 23 direction. By connecting the plurality of jigs 21 according to the length of the metal pipe, even if the length is, for example, a long metal pipe having a length of 4 m or more, the plurality of jigs 21 apply the abrasive 2 to the metal pipe. It can be polished by pressing against the inner surface.

<Example>
The present inventors measured the arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing device 10 and compared it with the arithmetic average roughness (Ra) of the inner surface of the conventional stainless steel pipe.

<Table 1>

  Table 1 is a graph showing, as a comparative example, the arithmetic average roughness (Ra) in the circumferential direction of the inner surface of the stainless steel pipe polished by the conventional vertical polishing. In this vertical polishing, a file having a grain size of No. 90 in the first step, No. 120 in the second step, No. 140 in the third step, No. 240 in the fourth step, and No. 400 in the fifth step was used, and a total of five steps were used. Polished the inner surface of the stainless steel pipe. Note that the particle size of the file is based on the JIS standard “JIS R 6010 Regulation by particle size of abrasive for abrasive cloth”. Among a plurality of stainless steel pipes polished by such vertical polishing, the arithmetic mean roughness (Ra) in the circumferential direction of any two of the stainless steel pipes is 0.7576 μm for the first pipe and 0 for the second pipe. 0.6103 μm.

<Table 2>

  Table 2 is a graph in which the arithmetic mean roughness (Ra) in the circumferential direction of the inner surface of the stainless steel pipe 1 polished by the inner surface polishing device 10 according to the present invention is measured. In this polishing, a polishing liquid in which water as a liquid and aluminum oxide as an abrasive were mixed was used. In the first first step, the jig 21 was rotated at 300 rpm for 30 minutes using a brush 44 having a wire diameter of 0.5 mm. When the internal pressure at which the brush 44 pressed the inner surface of the stainless steel pipe 1 in the first step at an arbitrary time was measured, it was 120 N to 160 N. In the subsequent second step, the jig 21 was rotated at 300 rpm for 30 minutes using the brush 44 having a wire diameter of 0.4 mm. At an arbitrary time, in the second step, the internal pressure at which the brush 44 pressed the inner surface of the stainless steel pipe 1 was 160 N to 270 N. Of the plurality of stainless steel pipes polished by these two steps, the arithmetic mean roughness (Ra) in the circumferential direction of any two of the stainless steel pipes was 0.093 μm for the first pipe and 0.08 μm for the second pipe. It was 096 μm. From the above, it was found that the arithmetic average roughness (Ra) of the inner surface of the stainless steel pipe 1 according to the present invention was less than 0.1 μm. The arithmetic average roughness (Ra) is based on the provisions of JIS B 0031 (1994).

  As described above, the embodiments of the present invention have been described with reference to the drawings. However, it should be considered that the specific configuration is not limited to these embodiments. The scope of the present invention is shown not only by the description of the embodiment but also by the claims, and further includes meanings equivalent to the claims and all modifications within the scope.

  In the above embodiment, the inner surface of the stainless steel pipe 1 having a length of 4 m is polished with the eight jigs 21, but the present invention is not limited to this. One jig having the same length as the length of the stainless steel pipe may be used. At this time, the motor 30 and the jig 21 need not be moved in the direction of the shaft 23. The number of jigs is not limited to eight, and a plurality of jigs such as two or three may be used.

  Further, in the above-described embodiment, an interval L2 is provided between the adjacent jigs 21, and the interval L2 is shorter than the length L1 of the jig 21, but is not limited thereto. As long as the motor 30 can be moved in the axial direction to grind the entire inner surface of the stainless steel pipe, the interval L2 may be the same as the length L1 of the jig or may be longer than the length L1 of the jig.

  In the above embodiment, the dimension L3 between the tip of the brush 44 and the shaft 23 is larger than the dimension L4 which is half of the inner diameter of the stainless steel pipe 1, but is not limited thereto, and the dimension L3 may be equal to the dimension L4.

  In the above-described embodiment, the tube 45 having elasticity constitutes the inner elastic body. However, the present invention is not limited to this. For example, a spring or rubber may constitute the inner elastic body.

1 Stainless steel pipe (material to be polished)
2 abrasive 10 inner surface polishing device 12 pump (supply means)
21 Jig (rotating body)
22 shaft 23 axis 30 motor (drive means)
41 body 44 brush 45 tube (inner elastic body)
S space

Claims (9)

A metal pipe inner surface polishing apparatus for polishing an inner surface of a metal pipe that is a material to be polished,
A rotating body extending in the axial direction;
Driving means for rotating the rotating body about the axis,
Supply means for supplying a polishing liquid in which a granular abrasive and a liquid are mixed to the inside of the metal pipe,
With
The rotating body,
A brush having elasticity protruding in a radial direction orthogonal to the axis and provided radially outward, an inner elastic body provided radially inward from the brush, and integrally formed with the rotating body, A brush receiver provided with the inner elastic body, wherein a dimension between the shaft and the tip of the brush is at least half the inner diameter of the metal pipe;
While the rotating body is installed inside the metal pipe, the inner elastic body presses the brush radially outward, and the brush is supported on the side wall of the brush receiver so as to be movable in the radial direction. By applying an internal pressure of 80 N to 300 N while abutting on the inner surface of the metal pipe while the tip is upright, the abrasive supplied from the supply means and adhered to the inner surface of the metal pipe is pressed against the inner surface of the metal pipe. An inner surface polishing apparatus for a metal pipe, wherein the inner surface is polished. The rotating body,
A body extending in the axial direction;
The brush protruding from the main body radially outward perpendicular to the axis, and provided movably in the radial direction,
The inner elastic body provided between the shaft and the brush, and elastically presses the brush radially outward,
The apparatus for polishing the inner surface of a metal pipe according to claim 1, comprising:   The inner surface polishing of the metal pipe according to claim 1, wherein the brush and the inner elastic body come into contact with each other, and the inner elastic body directly presses the brush radially outward. apparatus. 4. The apparatus according to claim 1, wherein the plurality of brush receivers are provided at equal intervals in a circumferential direction of the rotating body . 5. In a state where the rotating body is installed inside the metal pipe,
5. The metal pipe inner surface polishing apparatus according to claim 1, wherein a tip portion of the brush abuts perpendicularly on an inner surface of the metal pipe. 6. In a state where the rotating body is installed inside the metal pipe,
The inner surface polishing apparatus for a metal pipe according to any one of claims 1 to 5, wherein a space is formed between an inner surface of the metal pipe and a surface of the rotating body.   The inner surface of a metal pipe according to any one of claims 1 to 6, wherein the driving unit moves the rotator along the axis while rotating the rotator about the axis. Polishing equipment.   The plurality of rotators are connected via a shaft in the axial direction, and an interval between adjacent rotators is shorter than a length of the rotator, wherein the number of the rotators is smaller than the length of the rotator. Polishing equipment for metal pipes.   2. The metal pipe according to claim 1, wherein the inner elastic body is compressed while the rotating body is installed inside the metal pipe, and elastically presses the brush radially outward. 3. Internal polishing equipment.