JP2023144719A - Grinding apparatus and method of manufacturing rare earth-based sintered magnet - Google Patents

Abstract

To improve dimensional accuracy of grinding by increasing the positioning accuracy of a workpiece during grinding.SOLUTION: A grinding apparatus includes: a grinding wheel supported so as to be rotatable about a central axis; and a support table having a sliding surface for slidably supporting a workpiece, the support table being disposed so as to sandwich the workpiece between the sliding surface and an outer peripheral surface of the grinding wheel. The outer peripheral surface of the grinding wheel has an arch-shaped curve in a cross section taken along a plane including the central axis. The support table has a plurality of slits formed in the sliding surface and two guides extending in parallel on both sides of the workpiece positioned on the sliding surface, and the plurality of slits are inclined with respect to a direction in which the guides extend.SELECTED DRAWING: Figure 1

Description

The present application relates to a grinding device and a method for manufacturing a rare earth sintered magnet.

Various continuous processing methods have been proposed as methods for processing rare earth-based sintered magnets into tile-shaped shapes (Patent Documents 1 to 3).

Japanese Patent Application Publication No. 11-347900 Japanese Patent Application Publication No. 2010-234496 Japanese Patent Application Publication No. 2002-178246

In these continuous processing methods, processing waste tends to accumulate on the table (transport table) that transports the rare earth sintered magnet workpiece. If machining debris is present on the conveyance table, the machining debris caught between the workpiece and the conveyance table may cause the position and orientation of the workpiece to fluctuate, thereby reducing machining accuracy.

Furthermore, if the width of the conveyance table (the interval between the guides located on both sides of the conveyance path) is set to be approximately the same as the width of the workpiece, the workpiece may hit the guides of the conveyance table and the workpiece may not be conveyed properly. Therefore, the width of the transport table needs to be larger than the width of the workpiece. However, if the width of the transfer table is larger than the width of the workpiece, the position of the workpiece may move in the width direction of the transfer table while the workpiece is being transferred, which is a disadvantage in that the position and orientation of the workpiece in the width direction with respect to the grinding wheel are likely to change. was there.

Embodiments of the present invention provide a grinding device and a method for manufacturing a rare earth sintered magnet that can solve these problems.

In an exemplary and non-limiting embodiment, the grinding device of the present disclosure includes a grinding wheel rotatably supported around a central axis and a support table having a sliding surface that slidably supports a workpiece. and a support table arranged to sandwich the workpiece between the sliding surface and the outer peripheral surface of the grinding wheel. The outer circumferential surface of the grinding wheel has an arch-like curve in a cross section taken along a plane including the central axis. The support table has a plurality of slits formed on the sliding surface and two guides extending in parallel on both sides of the workpiece located on the sliding surface, and the plurality of slits include: The guide is inclined with respect to the direction in which it extends.

In one embodiment, the inclination angle of each slit with respect to the direction in which the guide extends is 10 degrees or more and 80 degrees or less.

In one embodiment, the distance between the centers of the plurality of slits is 2 mm or more and 50 mm or less, and the width of each slit is 1 mm or more and 10 mm or less.

In one embodiment, the interval between the two guides is wider than the width of the workpiece, and when the outer peripheral surface of the grinding wheel is grinding the upper surface of the workpiece, one of the two guides It contacts one end in the width direction of the workpiece.

In one embodiment, the difference between the interval between the two guides and the width of the workpiece is 200 μm or more and 1 mm or less.

In one embodiment, the shape of the curved line in the cross section is symmetrical with respect to a reference plane perpendicular to the central axis, and the distance from the guide that contacts the one end of the workpiece to the reference plane is: It is shorter than the distance from the other guide that does not contact the workpiece to the reference plane.

In one embodiment, each of the plurality of slits extends from one of the two guides to the other.

In one embodiment, the two guides are fixed to the sliding surface of the support table so as to intersect with the plurality of slits.

In one embodiment, a pair of rollers transmitting force to the work so that the work moves along the sliding surface of the support table, and a conveyor that supplies the work to a position sandwiched between the pair of rollers. A device.

In an exemplary embodiment, the method for manufacturing a rare earth sintered magnet of the present disclosure includes the steps of preparing a workpiece of a rare earth sintered magnet, and processing the workpiece using any of the grinding devices described above. Thereby, the method includes a step of forming a processed shape of the upper surface of the workpiece using the outer circumferential surface of the grinding wheel.

According to the embodiment of the present invention, processing waste is less likely to accumulate on the conveyance table. Further, since the position of the workpiece in the width direction during grinding is regulated, the present invention provides a grinding device and a method for manufacturing a rare earth sintered magnet that realizes an appropriate position and orientation of the workpiece with respect to the grinding wheel. I can do it.

FIG. 1 is a schematic diagram showing a configuration example of a grinding device in an embodiment of the present disclosure. 2 is a sectional view taken along the line II-II in FIG. 1. FIG. FIG. 3 is a top view schematically showing the support table in this embodiment. FIG. 2 is a perspective view schematically showing a support table in this embodiment. FIG. 3 is a schematic cross-sectional view showing the center-to-center distance P and width D of slits in the support table. FIG. 3 is a perspective view of a support table with a guide attached thereto; FIG. 3 is a top view schematically showing the movement of a workpiece moving on a support table.

Embodiments of the present invention will be described below. However, more detailed explanation than necessary may be omitted. For example, detailed descriptions of well-known matters and redundant descriptions of substantially the same configurations may be omitted. This is to avoid unnecessary redundancy in the following description and to facilitate understanding by those skilled in the art. The inventors have provided the accompanying drawings and the following description to enable those skilled in the art to fully understand the present disclosure, and are not intended to limit the subject matter recited in the claims. do not have. In the following description, components having the same or similar functions are given the same reference numerals.

The following embodiments are illustrative, and the technology of the present disclosure is not limited to the following embodiments. For example, the numerical values, shapes, materials, steps, order of steps, layout of display screens, etc. shown in the following embodiments are merely examples, and various modifications can be made as long as there is no technical contradiction. Moreover, it is possible to combine one aspect with another aspect as long as there is no technical contradiction.

First, an example of the configuration of the grinding device in this embodiment will be described with reference to FIGS. 1 and 2. FIG. 1 is a schematic diagram showing a configuration example of a grinding device in an embodiment of the present disclosure. FIG. 2 is a sectional view taken along line II-II in FIG. In the figure, the X, Y, and Z axes perpendicular to the difference are shown for reference.

The grinding device 100 in this embodiment includes a grinding wheel 10, a support table 30, and a conveyance table 40. The grinding wheel 10 is rotatably supported around a central axis C. In this example, central axis C is parallel to the X-axis. The grinding wheel 10 has a generally disk or cylindrical shape, and is axially symmetrical with respect to the central axis C. As shown in FIG. 2, the outer circumferential surface 10S of the grinding wheel 10 has an arch-like curve in a cross section taken along a plane including the central axis C. In this example, the arch-like curve has a convex shape toward the central axis C.

High-hardness abrasive grains such as diamond are fixed to the outer circumferential surface 10S of the grinding wheel 10. The outer circumferential surface 10S of the grinding wheel 10 contacts the upper surface of the workpiece 20 to grind the upper surface of the workpiece 20. Such grinding is sometimes called "shape processing." The upper surface of the workpiece 20 after the grinding process has a cross-sectional shape defined by the curved shape of the outer peripheral surface 10S of the grinding wheel 10. The workpiece 20 in this embodiment has an upwardly convex semicylindrical shape. The size, shape, and material of the work 20 are not particularly limited.

The grinding wheel 10 is driven by, for example, an electric motor. In FIG. 1, the grinding wheel 10 rotates counterclockwise. When the workpiece 20 is a rare earth sintered magnet, the rotational speed is, for example, 1000 to 5000 revolutions/minute. The diameter of the grinding wheel 10 is, for example, in the range of 100 to 300 mm. The speed (circumferential speed) at which the outer circumferential surface 10S of the grinding wheel 10 moves in the negative direction of the Z-axis relative to the upper surface of the workpiece 20 may be, for example, 1500 to 2000 m/min. These numerical values are merely examples, and can be changed as appropriate depending on the size, size, material, etc. of the workpiece 20.

The support table 30 has a sliding surface 30S that slidably supports the workpiece 20. The support table 30 is arranged so that the workpiece 20 is sandwiched between the sliding surface 30S and the outer peripheral surface 10S of the grinding wheel 10. Details of the configuration example of the support table 30 will be described later.

In this embodiment, a pair of rollers 50A, 50B transmitting force to the workpiece 20 so that the workpiece 20 moves along the sliding surface 30S of the support table 30, and a position between the pair of rollers 50A, 50B. 20. The pair of rollers 50A, 50B may be made of an elastic material such as urethane. The pair of rollers 50A and 50B are arranged so as to sandwich the workpiece 20 from above and below while rotating. An example of the conveyance device is a belt conveyor on which the workpiece 20 is placed and moved. The workpiece 20 that has been moving on the belt conveyor is pushed out in the positive direction of the Z-axis toward the processing position of the grinding wheel 10 by a pair of rotating rollers 50A and 50B. The workpiece 20 being processed by the grinding wheel 10 comes into contact with the workpiece 20 to be processed next, and the force by the rollers 50A and 50B (in the positive direction of the Z-axis) force) is transmitted.

Next, a configuration example and function of the support table 30 will be explained with reference to FIGS. 3 to 7. First, refer to FIGS. 3 and 4. FIG. 3 is a top view schematically showing the support table 30 in this embodiment. FIG. 4 is a perspective view schematically showing the support table 30 in this embodiment.

As shown in these figures, the support table 30 has a plurality of slits 32 formed in the sliding surface 30S. The slit 32 only needs to have a size that allows processing waste to be discharged downward. When the upper surface portion of the support table 30 is formed of, for example, a metal plate, the slit 32 is an opening that penetrates the metal plate from the upper surface to the lower surface. Machining waste is removed from the sliding surface 30S through this opening. Therefore, it is possible to suppress machining waste from entering between the sliding surface 30S and the workpiece 20, and improve the dimensional accuracy of the grinding process.

FIG. 5 is a schematic cross-sectional view showing the center-to-center distance P and width D of the slits in the support table 30. In this embodiment, the distance P between the centers of the plurality of slits 32 is 2 mm or more and 50 mm or less. Further, the width D of each slit 32 is 1 mm or more and 10 mm or less.

The sliding surface 30S of the support table 30 is on the same plane except for the slit 32, and is flat and smooth as a whole. The workpiece 20 is subjected to a grinding process by the grinding wheel 10 while moving on the sliding surface 30S of the support table 30. Therefore, the support table 30 functions as a "feed table" or "bottom surface reference jig" for the grinding process. The support table 30 may include a top plate in which a plurality of slits 30S are formed, and a support member that supports the top plate. In the support table 30, the structure other than the sliding surface 30S in which the slit 32 is formed is arbitrary. A container for collecting processing waste falling from the slit 32S may be arranged below.

Next, refer to FIGS. 6 and 7. FIG. 6 is a perspective view of a support table with a pair of guides attached thereto. FIG. 7 is a top view schematically showing the movement of the workpiece 20 moving on the support table 30.

As shown in FIGS. 6 and 7, the support table 30 has two guides 34A and 34B extending in parallel along the Z-axis direction on both sides of the workpiece 20 that moves on the sliding surface 30S. The plurality of slits 32 are inclined with respect to the direction in which the guides 34A and 34B extend (Z-axis direction). In this embodiment, the inclination angle θ of each slit 32 with respect to the direction in which the guides 34A and 34B extend is 10 degrees or more and 80 degrees or less. The lower limit of the inclination angle θ is, for example, 20 degrees or more, or 30 degrees or more. Further, the upper limit value of the inclination angle θ is, for example, 70 degrees or less, or 60 degrees or less. In the illustrated example, the tilt angle θ is 45 degrees.

In this embodiment, the plurality of slits 32 each extend from one of the two guides 34A, 34B to the other. More specifically, the two guides 34A and 34B are fixed to the sliding surface 30S of the support table 30 so as to intersect with the plurality of slits 32. This fixation may be performed using screws (not shown) or the like. In the case of screwing, it is also easy to change the fixing positions of the two guides 34A and 34B depending on the width of the workpiece 20 to be processed.

According to the inventor's experiments, when the workpiece 20 is processed by the grinding wheel 10, the sliding surface 30S of the support table 30 is provided with a plurality of diagonally extending slits 32, so that the workpiece 20 is moved in the X-axis direction. It was found that a force is generated to move the object. In the illustrated example, a force is applied to move the workpiece 20 in the positive direction of the X-axis. This force is generated when the workpiece 20 is sandwiched between the grinding wheel 10 and the support table 30 and is pressed by the grinding wheel 10 or the like.

In this embodiment, the interval between the two guides 34A and 34B is wider than the width W of the workpiece 20. As described above, when the workpiece 20 is ground by the grinding wheel 10, the workpiece 20 receives the above force and moves in the positive direction of the X-axis direction. As a result of such a force acting in one direction, one of the two guides 34A and 34B (guide 34A in the illustrated example) comes into contact with one end of the workpiece 20 in the width direction. As a result, the position and orientation of the workpiece 20 in the width direction during the grinding process is regulated by one of the two guides 34A and 34B (guide 34A in the illustrated example).

In this embodiment, the difference between the interval between the two guides 34A and 34B and the width W of the workpiece 20 is 200 μm or more and 1 mm or less. The difference between the distance between the two guides 34A, 34B and the width W of the workpiece 20 defines the size of the gap between the guides 34A, 34B and the workpiece 20. If the total of the gaps formed on both sides of the workpiece 20 is within the above numerical range, the workpiece 20 can smoothly move in the area sandwiched between the two guides 34A and 34B.

When the slit 32 of the support table 30 does not exist, the position (X coordinate) of the workpiece 20 in the width direction (X-axis direction) varies within a range of 200 μm or more and 1 mm or less. Even this degree of variation may not be acceptable depending on the use of the workpiece 20 because the dimensional accuracy will deteriorate. According to this embodiment, when the grinding wheel 10 presses the workpiece 20, there is no gap between the guide 34A and the workpiece 20, and the position (X coordinate) in the width direction (X-axis direction) of the workpiece 20 is within an extremely small range. This results in good reproducibility.

In the present embodiment, as shown in FIG. 2, the curved shape of the outer circumferential surface 10S of the grinding wheel 10 in a cross section taken along a plane including the central axis C is symmetrical with respect to the reference plane Ref orthogonal to the central axis C. It is. In the example shown in FIG. 7, the guide 34A contacts one end of the workpiece 20 during the grinding process. The distance from the guide 34A that contacts the work 20 to the reference plane Ref is set so as to realize a desired design value, and is greater than the distance from the other guide 34B that does not contact the work 20 to the reference plane Ref. It's also short.

As is clear from the above description, according to the grinding device 100 of the present embodiment, the operation of the diagonal slits 32 makes it difficult for machining waste to accumulate. Furthermore, due to the force that the workpiece 20 receives from the diagonal slit 32 during the grinding process, the position of the workpiece 20 in the width direction during processing is regulated by one of the guides, and the appropriate position and orientation of the workpiece 20 with respect to the grinding wheel are controlled. Realize. This improves the processing accuracy of the workpiece 20 and makes it possible to obtain a processed product having the desired curved surface shape.

The grinding apparatus 100 of this embodiment can be suitably used for processing the shape of a rare earth sintered magnet.

The method for manufacturing a rare earth sintered magnet according to the embodiment of the present disclosure includes a step of preparing a work 20 of a rare earth sintered magnet, and processing the work 20 using the grinding device 100 so that the outer circumferential surface of the grinding wheel 10 is 10S to form a processed shape on the upper surface of the workpiece 20.

According to this embodiment of the method for manufacturing a rare earth sintered magnet, it is possible to improve the dimensional accuracy of the semicircular sintered rare earth magnet. Such a rare earth sintered magnet can be suitably used, for example, as a permanent magnet for a rotor in an electric motor.

10... Grinding wheel 10S... Outer peripheral surface 20... Workpiece 30... Support table 30S... Sliding surface 34A, 34B... Guide 40... Conveyance table 50A, 50B... Feed Roller 100...Grinding device

Claims (10)

a grinding wheel rotatably supported around a central axis;
a support table having a sliding surface that slidably supports a workpiece, the support table being arranged so as to sandwich the workpiece between the sliding surface and the outer peripheral surface of the grinding wheel;
Equipped with
The outer circumferential surface of the grinding wheel has an arch-like curve in a cross section cut along a plane including the central axis,
The support table is
comprising a plurality of slits formed on the sliding surface and two guides extending in parallel on both sides of the workpiece located on the sliding surface,
A grinding device, wherein the plurality of slits are inclined with respect to the direction in which the guide extends. The grinding device according to claim 1, wherein the inclination angle of each slit with respect to the direction in which the guide extends is 10 degrees or more and 80 degrees or less. The grinding device according to claim 1 or 2, wherein the distance between the centers of the plurality of slits is 2 mm or more and 50 mm or less, and the width of each slit is 1 mm or more and 10 mm or less. The interval between the two guides is wider than the width of the workpiece,
Any one of claims 1 to 3, wherein when the outer peripheral surface of the grinding wheel is grinding the upper surface of the workpiece, one of the two guides contacts one end in the width direction of the workpiece. Grinding equipment as described in section. The grinding device according to claim 4, wherein a difference between the interval between the two guides and the width of the workpiece is 200 μm or more and 1 mm or less. The shape of the curve in the cross section is symmetrical with respect to a reference plane perpendicular to the central axis,
The distance from the guide that contacts the one end of the workpiece to the reference plane is:
The grinding device according to claim 4 or 5, wherein the distance is shorter than the distance from the other guide that does not contact the workpiece to the reference plane. The grinding device according to any one of claims 1 to 6, wherein each of the plurality of slits extends from one of the two guides to the other. The grinding device according to claim 7, wherein the two guides are fixed to the sliding surface of the support table so as to intersect with the plurality of slits. a pair of rollers that transmit force to the work so that the work moves along the sliding surface of the support table;
a conveying device that supplies the workpiece to a position sandwiched between the pair of rollers;
The grinding device according to any one of claims 1 to 8, comprising: A step of preparing a rare earth sintered magnet workpiece,
forming a processed shape of the upper surface of the workpiece using the outer circumferential surface of the grinding wheel by processing the workpiece using the grinding device according to any one of claims 1 to 9;
A method for producing a rare earth sintered magnet, including:

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