JPH04210367A - Magnetic tool for magnetic polishing device - Google Patents

Abstract

PURPOSE:To make polishing chip, worn abrasive grain, etc., not interrupt polishing by forming at least one groove at the contact part of a tool main body. CONSTITUTION:A tool main body 72 having a contact part 74 abutted directly or indirectly on the internal face of the body to be worked, and having magnetism is arranged. This tool main body 72 has at least one groove 78 at the contact part 74. Therefore, at the rotation time of a tool 70, this groove 78 acts as an escape way for polishing chips, worn abrasive grains, etc., so the polishing chips, worn abrasive grains, etc., do not become obstacle to polishing. Also, this groove 78 acts to feed to the contact part 74 of the tool the work liquid including new abrasive grains. Moreover, the bearing between the tool 70 and the face to be polished is large, because of the area abutting on the face to be polished directly or indirectly becoming less by the part of the groove 78.

Description

[Detailed description of the invention]

[0001]

[Industrial Application Field] The present invention relates to a magnetic polishing device for polishing the circular inner surface of a workpiece, such as a pipe, using a magnetic field that moves relative to the axis of the workpiece. Regarding magnetic tools. [0002]

[Prior Art] A magnetic tool for polishing is placed inside a non-magnetic workpiece having a circular inner surface, that is, a surface to be polished, and this tool is applied to the workpiece by a magnetic field rotating around the axis of the workpiece. A magnetic polishing device that polishes the surface to be polished by rotating the polishing device is described in the Journal of the Japan Society for Precision Engineering, Vol. 55, No. 10, 148-
It is described on page 153 and in JP-A-62-102969. [0003] In this type of magnetic polishing apparatus, means for generating a magnetic field for rotating the tool includes a plurality of electromagnets each having a coil wound around an iron core. The electromagnets are arranged at equal angular intervals around the axis of the workpiece so that the iron core extends radially with respect to the axis of the workpiece, and the end face of the iron core, that is, the magnetic pole face, is on the side of the axis of the workpiece. There is. [0004] When an alternating current, such as a three-phase alternating current, is supplied to the coil of an electromagnet, the magnetic field generated by the magnetic field generating means is
Rotated around the workpiece. The rotation of the magnetic field causes the tool to rotate about the axis of the workpiece while in contact with the surface to be polished, so that the surface to be polished is polished. [0005] In conventional magnetic tools, the contact part that comes into contact with the surface to be polished is a smooth surface, so polishing debris, abrasive grains, etc. are generated between the contact part of the tool and the surface to be polished. get inside and interfere with polishing. In addition, the total area in contact with the surface to be polished is large,
Abrasive grains may be uniformly supplied and distributed over the entire contact surface. Furthermore, when the total contact area between the contact portion and the surface to be polished is large, the pressing force of the tool on the surface to be polished, that is, the contact pressure between the tool and the surface to be polished becomes small, and as a result, the polishing efficiency is low. [0006]

[Problems to be Solved] The present invention prevents polishing debris, abrasive grains, etc. from interfering with polishing, and also allows machining fluid containing new abrasive grains to be supplied to the contact portion of a tool. An object of the present invention is to provide a magnetic tool for a magnetic polishing device, which increases the surface pressure between the tool and the surface to be polished, thereby increasing the polishing efficiency. [0007]

[Solution, operation, and effect] The magnetic tool for a magnetic polishing apparatus of the present invention has a magnetic tool main body that has a contact portion that comes into direct or indirect contact with the circular polishing surface of the workpiece. include. The tool body has at least one groove in the contact portion. [0008] During polishing, the tool is rotated around the axis of the workpiece by a rotating magnetic field generated by the magnetic field generating means, with the contact portion being in direct or indirect contact with the surface to be polished. . [0009] When the tool rotates, the groove acts as an escape route for polishing debris, abrasive grains, etc., so that the polishing debris, abrasive grains, etc. do not interfere with polishing. The grooves also serve to supply machining fluid containing fresh abrasive grains to the contact portion of the tool. Furthermore, since the area of the contact portion of the tool body that directly or indirectly contacts the surface to be polished is reduced by the groove, the contact pressure between the tool and the surface to be polished is large. [00101 As described above, according to the present invention, polishing waste,
Polishing efficiency is significantly improved because abrasive grains do not interfere with polishing, machining fluid containing new abrasive grains is constantly supplied to the contact area of the tool, and the contact pressure between the tool and the surface to be polished increases. do. [00111 A plurality of first grooves and a plurality of second grooves located between the first grooves and having a width and a depth smaller than the first grooves may be formed in the contact portion. [0012] The tool may further include a cover member disposed on the tool body so as to cover at least the contact portion. In this case, it is preferable that a notch corresponding to the groove is formed in the cover member. [0013] If a plurality of corner portions defined by the surface of the contact portion and the groove are formed in the contact portion, the magnetic flux that provides rotational force to the tool is dispersed to each corner portion, so that the tool and the workpiece are The contact pressure with the [0014]

[Example] Referring to FIGS. 1 and 2, reference numeral 70 will be described later.
A magnetic polishing apparatus 10 using a magnetic tool, which will be described in detail with reference to FIG. 1, includes a box-shaped frame 12 housing a power supply for the magnetic polishing apparatus. The frame 12 is
Using a plurality of casters 14 attached to the lower surface, it can be moved to any desired position on the floor and releasably installed at that position. [0015] A magnetic field generator 16 that generates a rotating magnetic field is mounted on the frame 12. Magnetic field generator 1
6 is an annular yoke 18 made of a magnetic material;
It is composed of a plurality of (six in the illustrated example) electromagnets 20 arranged at equal angular intervals, and a yoke 18.
A plurality of brackets 22 are arranged so that the axis of the brackets 22 extends almost horizontally.
It is attached to the frame 12 by. [0016] As shown in FIGS. 3 to 7, each electromagnet 20 has an iron core 24, a bobbin 26 made of an electrically insulating material through which the iron core is immovably penetrated in the longitudinal direction, and has a truncated quadrangular pyramid shape. and a coil 28 wound around a bobbin 26. [0017] Each iron core 24 is attached to the yoke 18 by a connector 30 so as to extend in the radial direction of the yoke 18, and is also magnetically connected to the yoke 18. [0018] In the illustrated example, each core 24 is formed by stacking a plurality of band-shaped magnetic plates electrically insulated from each other, but it may also be round or prismatic. The tip of each core 24 acts as a square magnetic pole surface. [0019] The pole faces jointly define a space within which the workpiece 32 is received. The workpiece 32 has a circular inner surface, that is, a polished surface, like a pipe, and is made of a non-magnetic material such as stainless steel. [00201 In the illustrated example, one magnetic field generator 16 is used, but a plurality of magnetic field generators 16 may be sequentially arranged in the axial direction of the workpiece 32. [0021] On the frame 12, there is also a workpiece 3
A drive mechanism 34 is disposed for gripping the workpiece 2, moving the workpiece in its axial direction, and rotating the workpiece 32 about its axis. [00221 As shown in FIG. 3, the drive mechanism 34 includes a slider 3 movable in a direction parallel to the central axis of the yoke 18.
6. Slider 36 is supported on a rail assembly 38 secured to frame 12. [0023] In the illustrated example, the rail assembly 38 includes a pair of rails 40 extending parallel to each other and parallel to the central axis of the yoke 18, supported by a pair of brackets 42 fixed to the frame 12; slider 36 to rail 4
Supports 0. [0024] The chuck 44 that grips the workpiece 32 is
It is arranged on a pair of support members 46 extending upward from the slider 36 in parallel with each other, and the workpiece 32 is supported by bearings (not shown) attached to the support members 46.
is rotatably supported around the axis of. [00251 As shown in FIG. 3, the moving mechanism 50 for moving the workpiece 32 in its axial direction includes a rotation source 52 including an electric motor and a speed reducer, a cam disc 54 attached to its rotating shaft, and a cam. A crankshaft 56 that converts the rotational motion of the disk 54 into reciprocating motion in the axial direction of the workpiece.
Equipped with. [0026] One end of the crankshaft 56 is connected to the outer peripheral edge of the cam disk 54, and the other end is connected to the slider 36 via a bracket 58. Therefore, the slider 36 rotates the workpiece 3 due to the rotation of the rotation source 52.
The chuck 44 is reciprocated in the axial direction of the chuck 44.
are also moved back and forth in the same direction. [00271 As shown in FIG. 3, the rotation mechanism 60 that rotates the workpiece 32 around its axis includes a rotation source 62 including an electric motor and a reduction gear, a pulley 64 attached to the rotation shaft, and a chuck 44. The chuck 44 is equipped with a pulley 66 attached to the outer peripheral surface of the workpiece 32 and an endless belt 68 wound around both the pulleys 64 and 66, and the chuck 44 is rotated around the axis of the workpiece 32 by rotation of the rotation source 62. . [00281 As shown in FIG. 4, the magnetic tool 70 has a rectangular parallelepiped tool main body 72 containing a magnetic material or a permanent magnet material.
including. The tool main body 72 has four arcuate parts 74
．． 74, 76.76, and the workpiece 32 is placed so that the portion 74.74 or 76.76 comes into contact with the surface to be polished.
placed within. [0029] A plurality of grooves 78 are formed in each of the portions 74.74 and 76.76. In the illustrated example, the grooves 78 are grooves that extend in the circumferential direction of the arc surface of the corresponding portion and are parallel to each other, as shown in FIG. 5A. [0030] The L ribs and grooves can have any shape. Alternatively, grooves may be formed on the entire outer surface of the main body of the tool. [00311 The grooves 80 shown in FIG. 5B extend in a direction perpendicular to the circumferential direction of the arc surface of the corresponding portion and are parallel to each other. Further, the grooves 82 shown in FIG. 5C extend in a direction intersecting the circumferential direction of the arc surface of the corresponding portion and intersect with each other. Furthermore, the grooves 84 and 86 shown in FIGS. 5E and 5B, respectively, cooperate with each other to form a special pattern. [0032] The tool body 72 can be formed by making itself a magnetic material or a permanent magnet material, or can be formed by molding a granular magnetic material or a permanent magnet material together with a synthetic resin material. can. When the tool body 72 includes a permanent magnet material, the permanent magnet material is magnetized to cause the tool body 72 to act as a permanent magnet. [00331 As shown in FIG. 1, prior to polishing, the workpiece 32 extends through the chuck 44 and the space defined by the magnetic pole face of the iron core 24, and is slightly inclined with respect to the horizontal. , is gripped by the chuck 44. [00341] Next, the tool 70 is placed inside the workpiece 32, and a predetermined amount of liquid containing abrasive grains, ie, machining fluid, is supplied into the workpiece 32 from one end in the longitudinal direction by the syringe 88. [0035] The injector 88 preferably includes a regulator such as a valve that regulates the amount of processing fluid supplied. A slurry containing abrasive grains can be used as the processing liquid. [00361 The workpiece 32 is supported such that the height of the part on the side where the syringe 88 is placed is slightly higher than the height of the part on the opposite side. Therefore, the machining fluid moves within the workpiece 32 over time. [0037] During polishing, three-phase alternating current is supplied to each coil 28 of the electromagnet 20 to generate a rotating magnetic field from the magnetic pole surface of the iron core 24. A method of connecting the coil 28 and a three-phase AC power source is described in, for example, Japanese Patent Laid-Open No. 102969/1983. [0038] As a result, a rotating magnetic field is generated by changing the polarity of the electromagnet 20, and the tool 70 placed within the workpiece 32 comes into contact with the inner surface of the workpiece 32 as the rotating magnetic field moves. rotated circumferentially along the inner surface. The rotational speed of tool 70 can be changed by changing the frequency of the alternating current supplied to the electromagnet. [0039] During polishing, slider 36 is reciprocated by movement mechanism 50 at a frequency lower than the rotational frequency of tool 70. As a result, the workpiece 32 is reciprocated in its axial direction. [0040] In L, the tool 70 disposed within the workpiece 32 is restrained by the magnetic flux generated by the magnetic field generator 16 and is not displaced in the axial direction of the workpiece 32 with respect to the magnetic field generator 16. Therefore, relative movement occurs between the workpiece 32 and the tool 70 in the axial direction of the workpiece 32. [00411 During polishing, the chuck 44 is also rotated about the axis of the workpiece 32 by the rotation mechanism 60 at a frequency lower than the rotation frequency of the tool 70. This causes the workpiece 32 to rotate around its axis. [0042] The rotational frequency of the tool 70, the reciprocating frequency of the workpiece 32, and the rotational speed of the workpiece 32 are, for example, 30 to 50H2, 1 to 2H2, and 0°1, respectively.
~IHz. [00431 The rotation direction of the workpiece 32 may be the same as the rotation direction of the tool 70, or may be opposite. Further, the rotation and reciprocating motion of the workpiece 32 may be continuous or intermittent. [0044] The machining fluid in the workpiece 32 is
Even when the particles are rotated, they gather at the bottom of the surface to be polished due to their own weight, and as the workpiece 32 rotates, they adhere to the entire circumferential direction of the surface to be polished. Moreover, the machining fluid in the workpiece 32 is
The relative reciprocating motion of the workpiece 32 and the tool 70 and the slight inclination of the workpiece 32 relative to the horizontal cause the workpiece 32 to be moved in the longitudinal direction. As a result, the machining fluid in the workpiece 32 adheres uniformly over the entire surface to be polished. [00451 Due to the rotation of the tool 70 and the reciprocating motion of the workpiece 32, there is a relative relationship between the workpiece 32 and the tool 70 such that the tool 70 draws a spiral trajectory on the surface to be polished. movement occurs. The trajectory of the tool when the workpiece is moved in one direction in its axial direction and the trajectory of the tool when it is moved in the other direction intersect with each other. [0046] When polishing within the stroke range of the workpiece 32 by the moving mechanism 50 is completed, the gripping position of the workpiece 32 on the chuck 44 is changed, and polishing within the next range is performed. [00471 The range of reciprocating movement of the workpiece 32 can be adjusted by, for example, making the attachment of the crankshaft 56 to the cam disk 54 changeable. [00481 During polishing, it is preferable to supply the machining liquid into the workpiece 32 continuously or intermittently. It is also preferred that a chute and a container for receiving the machining fluid flowing out from the workpiece 32 be located on the side opposite to the syringe 88. [00491 According to the tool 70, when the tool 70 rotates, polishing debris and abrasive grains in the workpiece 32 pass through the grooves 78 and do not interfere with polishing. In addition, among the contact parts of the tool body,
Since the area in direct or indirect contact with the surface to be polished is reduced by the groove, the contact pressure between the tool and the surface to be polished is large. Additionally, machining fluid containing fresh abrasive grains is supplied to the contact portion of the tool. [00501 If the contact portion and groove of the tool have a shape in which a plurality of corners are formed in the contact portion by the surface of the contact portion and the groove, the magnetic flux that provides rotational force to the tool will be dispersed to each corner. , the surface pressure between the tool and the workpiece increases. [00511 The main body of the tool may have any shape other than a rectangular parallelepiped. [00521 The tool main body 90 shown in FIG. 6 has an isosceles triangular cross-sectional shape. The tool main body 90 has arcuate surfaces 92 at corner portions corresponding to both ends of the base of an isosceles triangle,
Further, it is arranged within the workpiece so that both arcuate surfaces 92 come into contact with the surface to be polished. Therefore, the tool main body 90 also has grooves 94 on both arcuate surfaces, that is, on both liquid contact portions 92. [0053] The shape and size of the groove formed in the tool body are arbitrary. For example, if the groove has a square or triangular cross-sectional shape, the width and depth of the groove should be 1 to 3 mm.
It can be done to a certain extent. [00541 The tool main body 96 shown in FIG. 7 includes a plurality of first grooves 98 having a quadrangular cross-sectional shape and a plurality of second grooves 100 formed between the first grooves and having a triangular cross-sectional shape. and has. The second groove 100 is smaller in width and depth than the first groove 98. Therefore, the first groove 98 acts as an escape route for polishing debris and abrasive grains, and the second groove 10
0 acts as a storage part for abrasive grains. [0055] For example, the width and depth of the first groove 98 can be about 1 to 3 mm, and the width and depth of the second groove 100 can be about 0.01 to 0.2 mm. . [0056] The magnetic tool 102 shown in FIG. 8 further includes a cover member 106 disposed around the tool main body 104. The cover member 106 is made of a material having a function of storing machining fluid, such as felt, cloth, or leather, and also has a notch 110 corresponding to the groove 108 formed in the tool main body 104.
has. [00571 The force bar member 106 may be made of a metal material having a hardness close to that of abrasive grains, such as tin or copper. Further, the cover member 106 may be arranged so as to cover at least the contact portion of the main tool.

[Brief explanation of the drawing]

FIG. 1 is a front view showing an embodiment of a magnetic polishing apparatus using a magnetic tool of the present invention.

FIG. 2 is an enlarged view showing one embodiment of a magnetic field generator.

FIG. 3 is a perspective view showing one embodiment of a drive mechanism.

FIG. 4 is a perspective view showing an embodiment of the magnetic tool of the present invention.

FIG. 5 is an enlarged view showing various shapes of grooves.

FIG. 6 is a perspective view showing another embodiment of the magnetic tool.

FIG. 7 is an enlarged cross-sectional view of a part of another embodiment of the groove.

FIG. 8 is an enlarged cross-sectional view of a part of still another embodiment of the magnetic tool.

[Explanation of symbols]

10 Magnetic polishing device 16 Magnetic field generator 20 Electromagnet 32 Workpiece 70.102 Magnetic tool 72.90, 96, 104 Tool main body 74, 76,
92 Contact portion 78, 80, 82, 84, 86, 94, 98, 100° 108 groove 106 Cover member 110 Notch

[Figure 3]

Claims (4)

[Claims] 1. A magnetic tool for use in a magnetic polishing device for polishing a circular inner surface of a workpiece, the tool having magnetism and having a contact portion that comes into direct or indirect contact with the inner surface of the workpiece. A magnetic tool for a magnetic polishing device, comprising a main body, the tool main body having at least one groove in the contact portion. 2. The tool main body includes a plurality of first grooves formed in the contact portion and a plurality of first grooves formed between the first grooves and having a width and a depth smaller than the first grooves. The magnetic tool according to claim 1, having two grooves. 3. The tool further includes a cover member disposed on the tool body so as to cover at least the contact portion, the cover member having a notch portion formed to correspond to the groove.
The magnetic tool according to claim 1 or 2. 4. The contact portion has a plurality of corners formed by the surface thereof and the groove.
Magnetic tools described in .