Magnet plate for linear motor

Abstract

The linear motor magnet plate of the present disclosure generates driving force for linear motion cooperating with an armature and comprises: a plate material having a first plate surface and a second plate surface opposite to the first plate surface and having a recessed portion recessed toward the second plate surface side in the first plate surface; a plurality of permanent magnets disposed on the first plate surface; a cover portion comprising a non-magnetic body and provided on the first plate surface so as to cover the plurality of permanent magnets; and a peeling prevention portion inserted into the recessed portion and preventing the cover portion from peeling from the plate material. The recessed portion has a structure for preventing the peeling prevention portion from falling out from the recessed portion.

Description

Technical Field

[0001] The present invention relates to a magnetic plate for a linear motor used as a field magnetic pole of a linear motor.

Background Art

[0002] In recent years, it has been proposed to use a linear motor as a drive device for various industrial machines such as a magnetic head drive mechanism of an OA machine, a spindle of a machine tool, or a table feed mechanism of a machine tool. In this type of linear motor, a magnetic plate having a plurality of plate-shaped permanent magnets is often used as a field magnetic pole.

[0003] Patent Document 1 below discloses fixing a permanent magnet with a pin-shaped restricting member in order to prevent displacement of the permanent magnet in the surface direction disposed on the magnetic plate. The restricting member has a lower portion press-fitted into a non-through hole of a plate material on which the permanent magnet is disposed, and an upper portion protruding from the non-through hole. The lower portion has a tip portion, a narrow portion, and a wide portion. The upper portion is a protruding portion protruding from the surface of the plate material. With such a configuration, when the restricting member is pushed into the non-through hole by a press, since the restricting member is formed of a material harder than the plate material, the deformed portion pressed by the wide portion is retracted into the space between the narrow portion and the non-through hole. Thereby, the restricting member is firmly fixed to the plate material.

[0004] Patent Document 1 below discloses using the above-described restricting member in order to prevent the resin layer from peeling off from the plate material. Concave portions and convex portions are formed on the protruding portion of the restricting member. Thereby, a gap is formed between the concave portion and the convex portion in the protruding portion. With such a configuration, when forming the resin layer, the resin before curing enters the gap of the protruding portion. Therefore, the restricting member can prevent the resin layer from peeling off from the plate material.

Prior Art Documents

Patent Documents

[0005] [Patent Document 1] Japanese Patent Publication No. 2013-198278 [Overview of the Initiative] [Problems that the invention aims to solve]

[0006] In the technology described in Patent Document 1, a regulating member having a tip, a narrow portion, and a wide portion must be formed, and the regulating member must be made from a material harder than the plate material. In other words, in the technology described in Patent Document 1, both the regulating member and the plate material must be considered in order to prevent the resin layer from peeling off from the plate material, and there was room for improvement in reducing costs. Therefore, there is a need for a magnet plate for a linear motor that can prevent the resin protecting the permanent magnet from peeling off from the plate material with a simple structure and at low cost. [Means for solving the problem]

[0007] One aspect of the present disclosure is a magnet plate for a linear motor that works in cooperation with an armature to generate a driving force for linear motion, comprising: a plate material having a first plate surface and a second plate surface opposite to the first plate surface, the first plate surface having a recess that is recessed toward the second plate surface; a plurality of permanent magnets arranged on the first plate surface; a cover portion made of a non-magnetic material and provided on the first plate surface so as to cover the plurality of permanent magnets; and a peeling prevention portion inserted into the recess to prevent the cover portion from peeling off from the plate material, wherein the recess is configured to prevent the peeling prevention portion from coming out of the recess. [Effects of the Invention]

[0008] According to one embodiment, a magnet plate for a linear motor can be provided that can prevent the resin protecting the permanent magnet from peeling off from the plate material with a simple and inexpensive configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This is a plan view showing a magnet plate for a linear motor according to the first embodiment of the present invention. [Figure 2]This is a front view longitudinal cross-sectional view showing a magnet plate for a linear motor according to the first embodiment of the present invention. [Figure 3] This is a front view showing a magnet plate for a linear motor according to a second embodiment of the present invention, with a portion shown in cross-section. [Figure 4] This is a front view longitudinal cross-sectional view showing a plate material of a magnet plate for a linear motor according to a third embodiment of the present invention. [Figure 5] This is a front view showing a magnet plate for a linear motor according to a third embodiment of the present invention, with a portion shown in cross-section. [Figure 6] This is a plan view showing a magnet plate for a linear motor according to a fourth embodiment of the present invention. [Figure 7] This is a front view longitudinal cross-sectional view showing a magnet plate for a linear motor according to a fourth embodiment of the present invention. [Figure 8] This is a plan view showing a modified example of a magnet plate for a linear motor according to the fourth embodiment. [Modes for carrying out the invention]

[0010] Hereinafter, a linear motor magnet plate according to one aspect of the present disclosure will be described with reference to the drawings. Referring to Figures 1 and 2, the linear motor magnet plate 1 of the first embodiment will be described. The linear motor magnet plate 1 is a component of a linear motor and works in cooperation with an armature (not shown) to generate a driving force for linear motion. The linear motor magnet plate 1 comprises a plate material 2, a permanent magnet 3, a cover portion 4, and a peeling prevention portion 5.

[0011] The plate material 2 is made of a metal that allows magnetic flux to pass through, for example, iron. The plate material 2 is a plate with a roughly rectangular shape in plan view. The plate material 2 has a first plate surface 6 that is usually located on the upper side and a second plate surface 7 that is located on the lower side opposite to the first plate surface 6. The plate material 2 has a plurality of recesses 8 in the first plate surface 6 that are recessed toward the second plate surface 7 side. The recesses 8 are open to the first plate surface 6. The plate material 2, which is roughly rectangular in plan view, has a plurality of through holes 9 that penetrate the plate material 2 along its long side (the side that extends along the m direction, which will be described later).

[0012] Multiple permanent magnets 3 are arranged on the first surface 6 of the plate material 2. Each set of permanent magnets 3 includes north-pole permanent magnets 3 and south-pole permanent magnets 3. As shown in Figure 1, the north-pole permanent magnets 3 and south-pole permanent magnets 3 are arranged alternately on the first surface 6 along the longitudinal direction of the plate material 2. The north-pole permanent magnets 3 and south-pole permanent magnets 3 are fixed to the first surface 6 with adhesive or the like. In this fixed state, a gap is formed between the north-pole permanent magnets 3 and the south-pole permanent magnets 3. In the first embodiment, the permanent magnets 3 are in the shape of a roughly rectangular plate in plan view. The north-pole permanent magnets 3 and south-pole permanent magnets 3 are arranged on the plate material 2 such that their long sides (sides extending along the direction perpendicular to the m direction, which will be described later) correspond to each other. In the state where the north pole permanent magnet 3 and the south pole permanent magnet 3 are arranged on the plate material 2, both longitudinal ends of the north pole permanent magnet 3 and both longitudinal ends of the south pole permanent magnet 3 are located inside the plate material 2, beyond the long side of the plate material 2.

[0013] The cover portion 4 is provided on the first plate surface 6 so as to cover the permanent magnet 3 provided on the plate material 2. The cover portion 4 is made of a non-magnetic material. For example, the cover portion 4 is made of resin. When the cover portion 4 is made of resin, molten resin material is poured into a mold containing the plate material 2 on which the permanent magnet 3 is provided, and then the resin material is hardened to form a cover portion 4 that is roughly rectangular in plan view on the plate material 2 (so-called insert molding). Multiple notches 10 that open outward are formed on the long side of the cover portion 4 (the side that extends along the m direction, which will be described later). The notches 10 are formed at positions corresponding to the through holes 9 in the plate material 2. Therefore, the opening of the through hole 9 on the first plate surface 6 side is exposed to the outside. Note that the method of forming the cover portion 4 is not limited to the method described above.

[0014] The peeling prevention part 5 prevents the cover part 4 from peeling off the plate material 2. The peeling prevention part 5 is fixed to the cover part 4 and inserted into the recess 8. The recess 8 has a configuration that prevents the peeling prevention part 5 from coming out of the recess 8. In the first embodiment, the recess 8 is a screw hole provided outside the region A where the plurality of permanent magnets 3 are arranged on the first plate surface 6. The screw hole 8 is provided on the long side portion of the plate material 2. Typically, the screw holes 8 are provided at the four corners of the plate material 2. A female screw is formed on the inner peripheral surface of the screw hole 8.

[0015] The peeling prevention part 5 is integrally formed with the resin cover part 4. The peeling prevention part 5 is formed when the molten resin material is poured into the screw hole 8 when the cover part 4 is formed as described above, and then the resin material poured into the screw hole 8 is cured. In this way, the peeling prevention part 5 is formed simultaneously with the cover part 4. With such a configuration, the peeling prevention part 5 integrally formed with the resin cover part 4 can prevent the cover part 4 from peeling off the plate material 2.

[0016] The armature is a component of a linear motor and generates a driving force for linear motion in cooperation with the linear motor magnet plate 1. The armature includes an iron core and windings. The iron core is the main body of the armature. The iron core has, for example, a structure in which a plurality of plate pieces made of a magnetic material are stacked. The winding is a wire wound around the slot of the iron core. Alternating current power is supplied to the winding from a power supply device not shown.

[0017] When single-phase alternating current or three-phase alternating current is applied to the winding of the armature as power, an attractive force and a repulsive force act between the traveling magnetic field generated in the winding and the magnetic field of the linear motor magnet plate 1, and a thrust is applied to the armature. As a result, the armature can move linearly along the m direction (arrangement direction) in which the plurality of permanent magnets 3 are arranged. In this way, the linear motor including the armature and the linear motor magnet plate 1 operates.

[0018] In the case of the magnetic plate 1 for a linear motor according to the first embodiment, the recess 8 has a configuration that prevents the peeling prevention portion 5 from coming out of the recess 8. Therefore, according to the magnetic plate 1 for a linear motor of the first embodiment, it is possible to simply and inexpensively prevent the cover portion 4 from peeling off from the plate material 2 as compared with the conventional case where the configurations of the recess and the peeling prevention portion are devised.

[0019] In the case of the magnetic plate 1 for a linear motor according to the first embodiment, the magnetic flux passes directly below the gap between the adjacent permanent magnets 3, 3 inside the plate material 2. In this case, if a peeling prevention portion integrally formed with the cover portion is inserted into the recess formed between the adjacent permanent magnets 3, 3, a portion without iron is formed in the path of the magnetic flux, so the flow of the magnetic flux deteriorates. On the contrary, the magnetic plate 1 for a linear motor according to the first embodiment has a configuration in which a peeling prevention portion 5 integrally formed with the cover portion 4 is inserted into a screw hole 8 provided outside the region A where the plurality of permanent magnets 3 are arranged. Therefore, according to the magnetic plate 1 for a linear motor of the first embodiment, since a portion without iron is not substantially formed in the path of the magnetic flux, the flow of the magnetic flux is not hindered.

[0020] In the case of the magnetic plate 1 for a linear motor according to the first embodiment, the peeling prevention portion 5 integrally formed with the cover portion 4 is inserted into the screw hole 8. Therefore, according to the magnetic plate 1 for a linear motor of the first embodiment, it is possible to prevent the cover portion 4 from peeling off from the plate material 2 with a simpler configuration.

[0021] Next, the second embodiment of the magnetic plate for a linear motor of the present invention will be described with reference to FIG. 3. Note that components having the same reference numerals as those in the first embodiment may have the same functions, and thus the description may be omitted hereinafter. The magnetic plate 1a for a linear motor according to the second embodiment is different from the first embodiment in the configurations of the recess 8 and the peeling prevention portion 5.

[0022] The recess 8 is a screw hole provided in region B of the first plate surface 6, corresponding to the gap between adjacent permanent magnets 3, 3. One or more screw holes 8 are provided in each of the regions B. Female threads are formed on the inner circumferential surface of the screw hole 8. A threadless portion 11 without female threads is provided at the bottom of the screw hole 8. In the second embodiment, there may be regions B where no screw holes 8 are formed.

[0023] The peeling prevention part 5 is a screw that is screwed into the recess 8. The screw 5 is made of a metal that allows magnetic flux to pass through. For example, the screw 5 is made of iron. In the second embodiment, the screw 5 is a countersunk screw, but it is not limited to this, and various types of screws may be used.

[0024] In the second embodiment, the cover portion 4 is provided on the plate material 2 as described above, with the screw 5 screwed into the screw hole 8. Specifically, the cover portion 4 is formed on the first plate surface 6 of the plate material 2 by pouring molten resin material into a mold containing the plate material 2 with the permanent magnet 3 and screw 5, and then hardening the resin material. As shown in Figure 3, the screw 5 is screwed into the screw hole 8 with the base end portion 12 of the male thread exposed from the screw hole 8. Therefore, the cover portion 4 is provided so as to cover the head of the screw 5 and the area around the base end portion 12 of the male thread portion of the screw 5. With this configuration, it is possible to prevent the cover portion 4 from peeling off the plate material 2 due to the screw 5 screwed into the screw hole 8.

[0025] As shown in Figure 3, when the screw 5 is screwed into the screw hole 8, the tip of the screw 5 is not inserted into the threadless portion 11. Therefore, the threadless portion 11 is a space without iron.

[0026] In the case of the linear motor magnet plate 1a of the second embodiment, the screw 5 is screwed into the screw hole 8 formed between adjacent permanent magnets 3, 3, excluding the unthreaded portion 11. Therefore, the linear motor magnet plate 1a of the second embodiment has fewer iron-free portions in the path of the magnetic flux, thus suppressing obstruction of the magnetic flux flow. Since the linear motor magnet plate 1a of the second embodiment suppresses obstruction of the magnetic flux flow, the position of the screw hole 8 can be freely set.

[0027] Next, a third embodiment of the linear motor magnet plate of the present invention will be described with reference to Figures 4 and 5. Note that components having the same reference numerals as those used in the first and second embodiments have the same function, and therefore their descriptions may be omitted below. The linear motor magnet plate 1b of the third embodiment differs from the second embodiment in the configuration of the recess 8.

[0028] The recess 8 is a screw hole provided in region B of the first plate surface 6, corresponding to the gap between adjacent permanent magnets 3, 3. One or more screw holes 8 are provided in each of the regions B. The bottom surface 13 of the screw hole 8 is flat. Female threads are formed on the inner circumferential surface of the screw hole 8, from the opening of the screw hole 8 to the bottom surface 13 of the screw hole 8. In the third embodiment, there may be regions B where no screw holes 8 are formed.

[0029] As shown in Figure 5, the screw 5 is screwed into the screw hole 8 with the base end 12 of the male thread exposed from the screw hole 8. In the third embodiment, the linear motor magnet plate 1b is provided on the first plate surface 6 of the plate material 2 with the screw 5 screwed into the screw hole 8, similar to the second embodiment. Therefore, the cover portion 4 is provided so as to cover the head of the screw 5 and the base end 12 of the male thread of the screw 5. With this configuration, it is possible to prevent the cover portion 4 from peeling off the plate material 2 due to the screw 5 screwed into the screw hole 8.

[0030] As described above, a female thread is formed on the inner circumferential surface of the screw hole 8, extending from the opening of the screw hole 8 to the flat bottom surface 13 of the screw hole 8. Therefore, in the case of the linear motor magnet plate 1b of the third embodiment, the screw 5 is screwed into the screw hole 8 formed between adjacent permanent magnets 3, 3, so as to reach the back of the screw hole 8. In the linear motor magnet plate 1b of the third embodiment, there is virtually no iron-free portion formed in the path of the magnetic flux, so the flow of magnetic flux is not obstructed.

[0031] Next, a fourth embodiment of the linear motor magnet plate of the present invention will be described with reference to Figures 6 and 7. Note that components having the same reference numerals as those used in the first embodiment may be omitted from further description as they perform the same function. The linear motor magnet plate 1c of the fourth embodiment differs from that of the first embodiment in the configuration of the recess 8.

[0032] The recesses 8 are provided on the first plate surface 6, excluding the area A where the multiple permanent magnets 3 are arranged. The recesses 8 are provided on the long sides of the plate material 2. Typically, the recesses 8 are provided at the four corners of the plate material 2. That is, the plate material 2 has a pair of recesses 8, 8 on each long side that are aligned with the m direction (direction of movement), which is also the direction of movement of the armature, which is a movable element. The recesses 8 are inclined with respect to a vertical plane P perpendicular to the first plate surface 6 and the second plate surface 7. Typically, of the pair of recesses 8, 8, one recess 8 is inclined toward the second plate surface 7 as it moves toward one side of the m direction, which is the direction of movement of the armature. Of the pair of recesses 8, 8, the other recess 8 is inclined toward the second plate surface 7 as it moves toward the other side of the m direction.

[0033] The peel-preventing portion 5 is integrally formed with the resin cover portion 4. The peel-preventing portion 5 is formed when the cover portion 4 is formed as in the first embodiment, after the molten resin material is poured into the recess 8 and the resin material poured into the recess 8 hardens. In this way, the peel-preventing portion 5 is formed simultaneously with the cover portion 4. With this configuration, the peel-preventing portion 5, which is integrally formed with the resin cover portion 4, can prevent the cover portion 4 from peeling off the plate material 2.

[0034] In the case of the linear motor magnet plate 1c of the fourth embodiment, a peeling prevention portion 5, which is integrally formed with the cover portion 4, is inserted into a recess 8 provided outside the region A where the multiple permanent magnets 3 are arranged. Therefore, according to the linear motor magnet plate 1c of the fourth embodiment, there is substantially no iron-free portion formed in the path of the magnetic flux, so the flow of magnetic flux is not obstructed.

[0035] In the case of the linear motor magnet plate 1c of the fourth embodiment, the peeling prevention portion 5, which is integrally formed with the cover portion 4, is inserted into the inclined recess 8. Therefore, according to the linear motor magnet plate 1c of the fourth embodiment, the peeling of the cover portion 4 from the plate material 2 can be prevented with a simpler configuration.

[0036] In the case of the linear motor magnet plate 1c of the fourth embodiment, of the pair of recesses 8, 8, one recess 8 is inclined toward the second plate surface 7 as it moves toward one side in the m direction, and the other recess 8 is inclined toward the second plate surface 7 as it moves toward the other side in the m direction. Therefore, the linear motor magnet plate 1c of the fourth embodiment can more effectively prevent the cover portion 4 from peeling off from the plate material 2.

[0037] Next, a modified example of the magnet plate for the linear motor of the present invention will be described with reference to Figure 8. Note that components having the same reference numerals as those used in the first embodiment and the fourth embodiment have the same function, and therefore their descriptions may be omitted below. The magnet plate 1d for the linear motor of this modified example differs from that of the fourth embodiment in the configuration of the recess 8.

[0038] The recesses 8 are provided on the first plate surface 6, excluding the area A where the multiple permanent magnets 3 are arranged. The recesses 8 are provided on the long sides of the plate material 2. Typically, the recesses 8 are provided at the four corners of the plate material 2. Each recess 8 is inclined toward the second plate surface 7 as it approaches the corresponding corner of the plate material 2, which is roughly rectangular in plan view. In this case, if the straight lines Q, R, S, and T are aligned along the extension direction of each recess 8 in the horizontal plane, then the angles α between adjacent lines Q, R, S, and T are equal. With this configuration, according to the linear motor magnet plate 1d of this modified example, no matter what direction a force is applied to the cover portion 4, the peeling prevention portion 5 catches on the recesses 8, effectively preventing the cover portion 4 from peeling off the plate material 2.

[0039] It should be noted that the present invention is not limited to the embodiments and modifications described above, and any modifications and improvements that can achieve the objectives of the present invention are included. For example, the embodiments and modifications described above can be combined as appropriate. [Explanation of Symbols]

[0040] 1. Magnet plate for linear motor 2 Board material 3 Permanent magnets 4. Cover section 5. Anti-peeling section (screw) 6 1st board surface 7 2nd board surface 8 recesses 12 Base end of male thread 13 Bottom surface of screw hole

Claims

1. A magnet plate for a linear motor that works in cooperation with an armature to generate driving force for linear motion, A board material having a first board surface and a second board surface opposite to the first board surface, and having a recess in the first board surface that is recessed toward the second board surface, A plurality of permanent magnets arranged on the first plate surface, A cover portion made of a non-magnetic material is provided on the first plate surface so as to cover the plurality of permanent magnets, The system includes a peeling prevention part that is inserted into the recess and prevents the cover from peeling off the plate material, The recess has a configuration that prevents the peeling prevention portion from coming out of the recess. The recess is a screw hole provided on the first plate surface other than the area where the plurality of permanent magnets are arranged. The peeling prevention portion is a magnet plate for a linear motor, integrally formed with the cover portion.

2. A magnet plate for a linear motor that works in cooperation with an armature to generate a driving force for linear motion, A board material having a first board surface and a second board surface opposite to the first board surface, and having a recess in the first board surface that is recessed toward the second board surface, A plurality of permanent magnets arranged on the first plate surface, A cover portion made of a non-magnetic material is provided on the first plate surface so as to cover the plurality of permanent magnets, The system includes a peeling prevention part that is inserted into the recess and prevents the cover from peeling off the plate material, The recess has a configuration that prevents the peeling prevention part from coming out of the recess, The recess is a screw hole provided in the region of the first plate surface corresponding to the gap between adjacent permanent magnets. The peeling prevention part is made of metal that allows magnetic flux to pass through, and is a screw that is screwed into the recess. The cover portion is a magnet plate for a linear motor, provided to cover the head of the peeling prevention portion and the base end of the male screw portion of the peeling prevention portion.

3. The bottom surface of the recess, which is a screw hole, is flat. The magnet plate for a linear motor according to claim 2, wherein a female thread is formed on the inner circumferential surface of the recess, extending from the opening of the recess to the bottom surface of the recess.

4. A magnet plate for a linear motor that works in cooperation with an armature to generate a driving force for linear motion, A board material having a first board surface and a second board surface opposite to the first board surface, and having a recess in the first board surface that is recessed toward the second board surface, A plurality of permanent magnets arranged on the first plate surface, A cover portion made of a non-magnetic material is provided on the first plate surface so as to cover the plurality of permanent magnets, The system includes a peeling prevention part that is inserted into the recess and prevents the cover from peeling off the plate material, The recess has a configuration that prevents the peeling prevention part from coming out of the recess, The recess is provided on the first plate surface, excluding the area where the plurality of permanent magnets are arranged, and is inclined with respect to a vertical plane perpendicular to the first and second plate surfaces. The peeling prevention portion is a magnet plate for a linear motor, integrally formed with the cover portion.

5. The plate material has a pair of recesses, The linear motor magnet plate according to claim 4, wherein of the pair of recesses, one recess is inclined toward the second plate surface as it moves toward one direction in the direction of movement of the armature, which is a movable element, and the other recess is inclined toward the second plate surface as it moves toward the other direction in the direction of movement.

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