Armature for linear motor

Abstract

An armature 1 for a linear motor comprises a fastening hole member 30 that is partially resin-molded and has a fastening hole 31, and a laminated core 10 that has a fastening hole member insertion part 13 into which the fastening hole member 30 is inserted. The laminated core 10 has a surface 10a that is provided on the opening side of the fastening hole 31, and an insertion hole 14 that is provided in the surface 10a and reaches the fastening hole 31 of the fastening hole member 30 inserted into the fastening hole member insertion part 13. The armature for a linear motor further comprises a bush 40 that is disposed in the insertion hole 14 and has a support surface 43 recessed from the surface 10a in a state of being disposed in the insertion hole 14.

Description

Armature for linear motor

[0001] The present disclosure relates to an armature for a linear motor.

[0002] Conventionally, as a core of an armature for a linear motor, there is one mainly composed of a laminated steel plate (laminated iron core) obtained by laminating a plurality of steel plates such as silicon steel plates. An armature for a linear motor provided with this type of core may be used in a machine tool or the like and may be used in an environment where it comes into contact with a liquid such as cutting fluid. When such a liquid penetrates into the inside of the core of the armature for a linear motor (between steel plates, etc.), it may adversely affect the performance of the armature for a linear motor or cause a failure.

[0003] In Patent Document 1, a technique for suppressing the penetration of liquid into an armature for a linear motor by providing a fastening member insertion member is disclosed.

[0004] Japanese Unexamined Patent Application Publication No. 2021-726,46

[0005] However, in the configuration of Patent Document 1, if a gap occurs between the fastening member insertion member and the core, there is a risk that liquid may penetrate through the gap.

[0006] An object of the present disclosure is to provide an armature for a linear motor that can prevent the penetration of liquid.

[0007] The present disclosure is an armature for a linear motor that is partially or entirely resin-molded, and includes a fastening hole member having a fastening hole, and a laminated core having a fastening hole member insertion portion into which the fastening hole member is inserted. The laminated core has a surface provided on the opening side of the fastening hole, and an insertion hole provided on the surface and reaching the fastening hole of the fastening hole member inserted into the fastening hole member insertion portion. The armature for a linear motor further includes a bush disposed in the insertion hole and having a support surface recessed from the surface in a state of being disposed in the insertion hole.

[0008] This is a perspective view showing the armature 1 for a linear motor according to the first embodiment. This is a perspective view showing the armature 1 for a linear motor with the molded resin part 50 and terminal part 60 omitted from Figure 1. This is an exploded perspective view showing the relationship between the laminated core 10, the fastening hole member 30, and the bush 40. This is a cross-sectional view of the armature 1 for a linear motor cut at the position indicated by arrows A-A in Figure 1. This is a diagram illustrating the molding process of the molded resin part 50. This is a perspective view showing an enlarged view of the area near the opening end of the insertion hole 14 before molding of the molded resin part 50. This is a perspective view showing an enlarged view of the area near the opening end of the insertion hole 14 after molding of the molded resin part 50. This is a diagram showing the armature 1 for a linear motor according to this embodiment with the O-ring 70 attached. This is a perspective view showing the armature 1B for a linear motor according to the second embodiment. This is a perspective view showing the cover member 80 in an disassembled state. This is a cross-sectional view of the armature 1B for a linear motor cut at the position indicated by arrows B-B in Figure 9. This is a cross-sectional view of the armature 1C for a linear motor according to the third embodiment, cut at the same position as in Figures 4 and 8 of the first embodiment.

[0009] The embodiments of this disclosure will be described in detail below with reference to the drawings. In the description of the second and subsequent embodiments, components common to the first embodiment will be denoted by the same reference numerals, and their descriptions will be omitted as appropriate.

[0010] (First Embodiment) Figure 1 is a perspective view showing the armature 1 for a linear motor according to the first embodiment. Figure 2 is a perspective view showing the armature 1 for a linear motor with the molded resin part 50 and terminal part 60 omitted from Figure 1. Figure 3 is an exploded perspective view showing the relationship between the laminated core 10, the fastening hole member 30, and the bush 40. Figure 4 is a cross-sectional view of the armature 1 for a linear motor cut at the position indicated by arrow A-A in Figure 1. Note that the orthogonal coordinates X, Y, and Z are also indicated in each figure and are used to describe directions in the following description. The armature 1 for a linear motor according to this embodiment comprises a laminated core 10, a coil 20, a fastening hole member 30, a bush 40, a molded resin part 50, and a terminal part 60.

[0011] The laminated core 10 is made of laminated steel sheets formed by stacking multiple steel sheets. For example, thin sheets made of electromagnetic steel sheets such as silicon steel sheets are used as steel sheets. The steel sheets have a predetermined magnetic pole shape and are stacked in a uniform shape to form the laminated core 10. The laminated core 10 is configured as a roughly rectangular parallelepiped, and on the -Z side surface, a plurality of grooves 11 extending in the X direction and a plurality of core portions 12 extending in the X direction at positions sandwiched between the grooves 11 are arranged along the Y direction, forming a roughly comb-like shape. As shown in Figure 2, a coil 20 is wound around the core portion 12, which is arranged across adjacent grooves 11. Including the core portions 12, the -Z side surface of the laminated core 10 forms roughly comb-like teeth.

[0012] Furthermore, the laminated core 10 has a fastening hole member insertion portion 13 that extends in the X direction. The fastening hole member insertion portion 13 is a roughly rectangular parallelepiped space into which the fastening hole member 30, described later, is inserted. In the following description, the surface of the laminated core 10 on the opening side of the fastening hole 31 when the fastening hole member 30 is inserted into the fastening hole member insertion portion 13, that is, the +Z side surface of the laminated core 10, will be referred to as the surface 10a of the laminated core 10. Furthermore, the laminated core 10 has an insertion hole 14 that opens on the surface 10a (the +Z side surface). The insertion hole 14 reaches the fastening hole 31 of the fastening hole member 30 inserted into the fastening hole member insertion portion 13. This insertion hole 14 is a hole through which fastening members such as screws and bolts (not shown) are inserted for attaching the armature 1 for the linear motor to a machine tool or the like. In this embodiment, the opening shape of the insertion hole 14 when viewed from the +Z side is roughly rectangular. Furthermore, the opening shape of the insertion hole 14 is not limited to a rectangular shape; it may also have rounded corners, or it may be a circular, oval, or elliptical shape.

[0013] The coil 20 is a wire wound around the core 12. AC power is supplied to the coil 20 from an external power supply (not shown) via the terminal 60. While Figure 2 illustrates an example with three coils 20, the number of coils 20 is not limited to three and can be appropriately set according to the desired characteristics.

[0014] The fastening hole member 30 is formed in a substantially rectangular parallelepiped shape and is inserted into the fastening hole member insertion portion 13 of the laminated core 10. The fastening hole member 30 has a fastening hole 31 that opens to the +Z side. The fastening hole 31 is a screw hole or bolt hole into which fastening members such as screws or bolts (not shown) are fastened for attaching the armature 1 for the linear motor to a machine tool or the like. In this embodiment, the fastening hole 31 is a screw hole or bolt hole, but it may also be a fastening hole that corresponds to other fastening structures such as press-fitting.

[0015] The bush 40 is positioned in the through hole 14 of the laminated core 10. The bush 40 has a cylindrical shape with a through hole 41. The -Z end face 42 of the bush 40 is positioned in contact with the -Z bottom surface of the through hole 14 and the +Z surface of the fastening hole member 30. When the bush 40 is positioned and placed in the through hole 14, the support surface 43, which is the +Z end face, is located recessed from the surface 10a of the laminated core 10. This support surface 43 is an annular surface that supports the O-ring 70, which will be described later.

[0016] In this embodiment, it is desirable that the bush 40 be made of an elastically deformable material. This is because it is possible to prevent liquid from entering the contact surface between the bush 40 and the fastening hole member 30. In this embodiment, rubber is used as the material for the bush 40. Here, an elastically deformable material does not need to be a perfectly elastic body, but includes materials that undergo some degree of plastic deformation while still retaining elastic deformation. Therefore, the bush 40 is not limited to rubber, but may be, for example, a resin molded product.

[0017] The molded resin portion 50 covers almost the entire armature 1 for the linear motor, preventing liquids such as cutting fluid used in machine tools during use from coming into contact with the laminated core 10. The molded resin portion 50 covers the laminated core 10 except for the front surface 10a and back surface 10b of the laminated core 10. In addition, as shown in Figure 4, the molded resin portion 50 is also provided between the coil 20 and the groove 11. However, the molded resin portion 50 is not provided on the support surface 43 of the bush 40 or on its inner side.

[0018] The molded resin part 50 is formed (resin molded) using a molded resin such as a resin filler. Figure 5 is a diagram illustrating the molding process of the molded resin part 50. Figure 5 is shown as a cross-section at the same position as in Figure 4. Also, Figure 5 shows the state before the molded resin is filled, with the mold 100 set. In addition, molds other than the mold 100 described here are not shown. To mold the molded resin part 50, the coil 20, fastening hole member 30, bush 40, and terminal part 60 are assembled in predetermined positions on the laminated core 10, the laminated core 10 is surrounded by the mold 100, etc., and the molded resin is filled into the mold. As shown in Figure 5, the mold 100, which is positioned to cover the surface 10a of the laminated core 10, is provided with a cylindrical protrusion 101 whose outer diameter is equal to that of the bush 40. During the molding of the molded resin part 50, the protrusions 101 are inserted into the through holes 14 where each bush 40 is located.

[0019] Figure 6 is a magnified perspective view showing the area near the opening end of the insertion hole 14 before molding of the molded resin portion 50. Figure 7 is a magnified perspective view showing the area near the opening end of the insertion hole 14 after molding of the molded resin portion 50. As shown in Figures 6 and 7, the gap that existed between the insertion hole 14 and the bush 40 before molding is filled with molded resin, and after molding, the molded resin portion 50 is formed and the bush 40 is fixed in the appropriate position. Furthermore, the support surface 43 of the bush 40 is exposed because the flow of molded resin is prevented by the protrusion 101 of the mold dies 100. This support surface 43 is recessed from the surface 10a of the laminated core 10. The molded resin portion 50 around the support surface 43 forms an inner wall portion 51 with a cylindrical inner surface shape that has an inner diameter approximately equal to the outer diameter shape of the bush 40.

[0020] In this embodiment, the molded resin part 50 is a part of the armature 1 for the linear motor that has been resin-molded. However, the entire armature 1 for the linear motor, or substantially the entire armature 1, may also be resin-molded. Substantially the entire armature means that the entire armature excluding the opening of the insertion hole 14 is resin-molded.

[0021] The terminal section 60 is connected to the coil 20 and receives AC power from an external power supply (not shown). The terminal section 60 is fixed by a molded resin section 50. An external cable is also connected to the terminal section 60, and a liquid ingress prevention structure is provided to prevent liquid from entering the interior when the cable is connected.

[0022] Figure 8 shows the linear motor armature 1 of this embodiment combined with an O-ring 70. Here, we will explain using the example of a case where the linear motor armature 1 of this embodiment is shipped in the form shown in Figure 1, and the user attaches it to their own machine tools, etc. When attaching the linear motor armature 1 to the user's machine tools, etc., fastening members such as screws or bolts are screwed into the fastening holes 31 of the fastening hole member 30 to attach the linear motor armature 1 to the required position. At this time, by placing the O-ring 70 on the support surface 43 of the bush 40 and attaching it, it is possible to prevent liquids such as cutting fluid from entering the inside of the laminated core 10. The thickness of the O-ring 70 is greater (thicker) than the amount of recess in the Z direction of the support surface 43 from the surface 10a of the laminated core 10. As a result, the O-ring 70 is appropriately crushed and deformed, preventing the entry of liquids. In addition, because the O-ring 70 is crushed and deformed, the gap between the support surface 43 and the object to which it is attached is reduced. Although not specifically shown in the figures, the surface 10a of the laminated core 10 shall be fitted with a sealing structure or the like to prevent liquid ingress appropriately, as in the conventional method, to the extent not shown in the figures.

[0023] In the configuration of the linear motor armature 1 of this embodiment, two paths are assumed for liquid intrusion: a path passing between the symmetrical member to which the linear motor armature 1 is attached (for example, the table of a machine tool) and the surface 10a of the laminated core 10 (hereinafter referred to as the mounting surface path), and a path passing around fastening members such as screws and bolts that are screwed into the fastening holes 31 (hereinafter referred to as the fastening member path). In the linear motor armature 1 of this embodiment, the mounting surface path is prevented from being accessed by an O-ring 70 being supported on the support surface 43 of the bush 40.

[0024] (Second Embodiment) Figure 9 is a perspective view showing the armature 1B for a linear motor of the second embodiment. Figure 10 is a perspective view showing the cover member 80 in a disassembled state. Figure 11 is a cross-sectional view of the armature 1B for a linear motor cut at the position indicated by arrow B-B in Figure 9. The armature 1B for a linear motor of the second embodiment has the same form as the armature 1 for a linear motor of the first embodiment, except that it includes an O-ring 70 and a cover member 80. Therefore, the same reference numerals are used for parts that perform the same functions as those of the first embodiment described above, and redundant explanations are omitted as appropriate.

[0025] The O-ring 70 is supported on the support surface 43 of the bush 40, similar to the first embodiment. The O-ring 70 is positioned between the support surface 43 and the cover member 80.

[0026] The cover member 80 covers the surface 10a of the laminated core 10 and the O-ring 70. When viewed from the +Z side in plan, the cover member 80 is larger than the surface 10a of the laminated core 10 and also covers a portion of the molded resin part 50. The cover member 80 has a through hole 81 at a position corresponding to the bush 40, and is attached to the +Z side of the laminated core 10 and the molded resin part 50 in alignment with the bush 40 and the fastening hole 31. The through hole 81 is large enough that the O-ring 70 cannot pass through, but is large enough for fastening members such as bolts corresponding to the fastening hole 31 to pass through. The cover member 80 can be made of, for example, a thin sheet material such as stainless steel or aluminum.

[0027] The cover member 80 is attached to the laminated core 10 and the molded resin part 50, for example, by an adhesive 90 that remains elastically deformable even after curing. As shown in Figure 11, the adhesive 90 is interposed between the cover member 80 and the surface 10a of the laminated core 10, so that the cover member 80 does not adhere tightly to the surface 10a and is attached without crushing the O-ring 70. When a user screws a fastening member such as a bolt into the fastening hole 31 to attach the linear motor armature 1B to an object to be mounted, such as a machine tool (for example, a machine table), the fastening force of the fastening member causes the adhesive 90 to elastically deform and the cover member 80 to deform, crushing the O-ring 70 and preventing liquid from entering. In other words, the O-ring 70 is crushed when it is fixed to the object to be mounted via the cover member 80. Thus, it is desirable that the O-ring 70 is not crushed when the linear motor armature 1B is in a standalone state before being attached to a machine tool or the like. As a result, the O-ring 70 is compressed when the armature 1B for the linear motor is first put into use, which suppresses the deterioration of the O-ring 70 and allows the O-ring 70 to maintain its effect of preventing liquid ingress for a long period of time.

[0028] In this embodiment, an example is shown in which the O-ring 70 is not crushed by interposing adhesive 90 between the cover member 80 and the surface 10a of the laminated core 10. However, this is not limited to this, and for example, the cover member 80 may be made of a thin material that is easily deformable, so that the part of the cover member 80 that contacts the O-ring 70 deforms towards the +Z side and does not crush the O-ring 70. Also, if the linear motor armature 1B is to be used immediately without being stored as a standalone unit, the cover member 80 may be attached with the O-ring 70 crushed.

[0029] (Third Embodiment) Figure 12 is a cross-sectional view of the armature 1C for the linear motor of the third embodiment, cut at the same position as in Figures 4 and 8 of the first embodiment. The armature 1C for the linear motor of the third embodiment has the same form as the armature 1 for the linear motor of the first embodiment, except that it is equipped with a second O-ring 71. Therefore, the same reference numerals are used for parts that perform the same functions as those of the first embodiment described above, and redundant explanations are omitted as appropriate.

[0030] As shown in Figure 12, in the armature 1C for the linear motor of the third embodiment, a second O-ring 71 is positioned between the fastening hole member 30 and the bush 40. In the armature 1 for the linear motor of the first embodiment, liquid ingress is prevented in the fastening member path by providing a molded resin portion 50 around the bush 40. In addition to this, in the armature 1C for the linear motor of the second embodiment, the provision of a second O-ring 71 between the fastening hole member 30 and the bush 40 further enhances the effect of preventing liquid ingress by preventing liquid ingress at the contact surface between the bush 40 and the fastening hole member 30.

[0031] Furthermore, in the armature 1C for the linear motor of the third embodiment, the bush 40 may be a rigid body that does not undergo substantially elastic deformation, as a second O-ring 71 is provided.

[0032] As an effect of at least one embodiment described above, it is possible to provide an armature for a linear motor that can prevent liquid ingress.

[0033] While this disclosure has been described in detail, it is not limited to the individual embodiments described above. These embodiments can be added, replaced, modified, partially deleted, etc., in any way that does not depart from the gist of this disclosure or from the spirit of this disclosure derived from the claims and their equivalents. Furthermore, these embodiments can be implemented in combination. For example, the order of operations and processes in the embodiments described above are shown as examples only and are not limited thereto. The same applies when numerical values ​​or mathematical formulas are used in the description of the embodiments described above.

[0034] With respect to the above embodiments and modifications, the following additional notes are disclosed. (Addendum 1) The armature for a linear motor (1, 1B, 1C) is a linear motor armature (1, 1B, 1C) which is partially or entirely resin-molded and comprises a fastening hole member (30) having a fastening hole (31) and a laminated core (10) having a fastening hole member insertion portion (13) into which the fastening hole member (30) is inserted, the laminated core (10) has a surface (10a) provided on the opening side of the fastening hole (31) and an insertion hole (14) provided on the surface (10a) that reaches the fastening hole (31) of the fastening hole member (30) inserted into the fastening hole member insertion portion (13), and further comprises a bush (40) disposed in the insertion hole (14) and having a support surface (43) recessed from the surface (10a) when disposed in the insertion hole (14).

[0035] (Note 2) The armature for the linear motor (1, 1B, 1C) described in Note 1 is characterized in that the support surface (43) supports the O-ring (70).

[0036] (Note 3) The armature (1B) for a linear motor described in Note 1 or Note 2 is characterized by comprising an O-ring (70) supported on the support surface (43) and a cover member (80) positioned to cover the O-ring (70).

[0037] (Note 4) The armature for the linear motor (1B) described in Note 3 is characterized in that the O-ring (70) is crushed when it is fixed to the object to be mounted via the cover member (80).

[0038] (Note 5) The armature for a linear motor (1, 1B, 1C) described in any of Notes 1 to 2 is characterized in that the bush (40) is elastically deformable.

[0039] (Note 6) The armature for a linear motor (1C) described in any of Notes 1 to 5 is characterized in that a second O-ring (71) is arranged between the fastening hole member (30) and the bush (40).

[0040] (Note 7) The armature (1C) for the linear motor described in Note 6 is characterized in that the bush (40) is a rigid body.

[0041] 1, 1B, 1C Linear motor armature 10 Laminated core 10a Front surface 10b Back surface 11 Groove 12 Core portion 13 Fastening hole member insertion portion 14 Through hole 20 Coil 30 Fastening hole member 31 Fastening hole 40 Bushing 41 Through hole 42 End face 43 Support surface 50 Molded resin portion 51 Inner wall portion 60 Terminal portion 70 O-ring 71 Second O-ring 80 Cover member 81 Through hole 90 Adhesive 100 Molding mold 101 Protrusion

Claims

1. An armature for a linear motor, which is partially or entirely resin-molded, comprising: a fastening hole member having fastening holes; and a laminated core having a fastening hole member insertion portion into which the fastening hole member is inserted, wherein the laminated core has a surface provided on the opening side of the fastening holes; and an insertion hole provided on the surface that reaches the fastening holes of the fastening hole member inserted into the fastening hole member insertion portion, and further comprises a bush disposed in the insertion hole, the bush having a support surface recessed from the surface when disposed in the insertion hole.

2. An armature for a linear motor according to claim 1, characterized in that the support surface supports an O-ring.

3. An armature for a linear motor according to claim 2, characterized by comprising: an O-ring supported on the support surface; and a cover member disposed to cover the O-ring.

4. The armature for a linear motor according to claim 3, characterized in that the O-ring is crushed when fixed to the object to be mounted via the cover member.

5. An armature for a linear motor according to claim 1 or claim 2, characterized in that the bush is elastically deformable.

6. An armature for a linear motor according to claim 1 or claim 2, characterized in that a second O-ring is disposed between the fastening hole member and the bush.

7. An armature for a linear motor according to claim 6, characterized in that the bush is a rigid body.

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