Encased armature of linear motor

Abstract

An encased armature of the present disclosure comprises: an armature having a core constituting a body, a coil provided to the core, and a resin part covering some or all of the core and the coil; and a case in which the armature can be housed. The case has a cylindrical case body covering the outside of the armature; a first lid portion that closes an opening on one end in the axial direction of the case body; a first elastic body that seals a gap between the case body and the first lid portion and that attaches the first lid portion to the case body; a second lid portion that closes an opening on the other end in the axial direction of the case body; and a second elastic body that seals a gap between the case body and the second lid portion and that attaches the second lid portion to the case body.

Description

Linear motor cased armature

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

[0002] In recent years, linear motors have been proposed as drive devices for various industrial machines, such as magnetic head drive mechanisms in office automation equipment and spindle or table feed mechanisms in machine tools. This type of linear motor uses an armature along with a magnet plate, which serves as a field pole. Known armatures include a core and coil molded in resin with the exposed armature, and a resin-molded core and coil housed in a case.

[0003] Linear motors are often incorporated into machines that perform processes that use cutting fluid, such as metalworking. For this reason, linear motors use the latter type of armature mentioned above, taking into consideration dustproofing and waterproofing. With the latter type, screws or welding are used to assemble the case into a box shape.

[0004] Japanese Patent Application Laid-Open No. 2019-115171

[0005] When assembling a case by welding, each component that makes up the case is welded together. Specifically, a case that has an upper wall, a lower wall, a left wall, a right wall, a front wall, and a rear wall must be welded individually. Therefore, when assembling a case by welding, there are many welding points. Having many welding points not only makes the welding work more time-consuming and labor-intensive, but also increases the possibility of poor welding.

[0006] Therefore, in order to solve the above-mentioned problems, there is a demand for an armature with a case that uses a case that can reduce the number of welding points.

[0007] The presently disclosed armature with a case includes an armature having a core serving as a main body, a coil provided on the core, and a resin portion covering part or all of the core and the coil, and a case capable of accommodating the armature. The case includes a cylindrical case body covering the outside of the armature, a first lid portion closing an opening at one axial end of the case body, a first elastic body sealing a gap between the case body and the first lid portion and attaching the first lid portion to the case body, a second lid portion closing an opening at the other axial end of the case body, and a second elastic body sealing a gap between the case body and the second lid portion and attaching the second lid portion to the case body.

[0008] FIG. 1 is a perspective view showing a cased armature according to a first embodiment of the present invention; FIG. 2 is an exploded perspective view showing a cased armature according to the first embodiment of the present invention, showing a state in which a part of the armature is pulled out from the case for ease of understanding; FIG. 3 is a perspective view showing a first cover part of the cased armature according to the first embodiment of the present invention, showing a state as seen from inside the case; FIG. 4 is an exploded perspective view showing a cased armature according to a second embodiment of the present invention, showing a state in which a part of the armature is pulled out from the case; FIG. 5 is an exploded perspective view showing a cased armature according to a third embodiment of the present invention, showing a state in which a part of the armature is pulled out from the case; and FIG. 6 is an exploded perspective view showing a cased armature according to a fourth embodiment of the present invention, showing a state in which a part of the armature is pulled out from the case.

[0009] A cased armature according to one aspect of the present disclosure will be described below with reference to the drawings. A cased armature 1 according to a first embodiment will be described with reference to Figs. 1 to 3. The cased armature 1 is a component of a linear motor, and cooperates with magnet plates used as field poles of the linear motor to generate driving force for linear motion. The cased armature 1 of this embodiment includes an armature 2 and a case 3.

[0010] The armature 2 has a conventionally known configuration. Typically, the armature 2 has a core 4, a coil 5, and a resin part (not shown). The core 4 is a member that forms the main body of the armature 2. The core 4 is roughly block-shaped and made of a magnetic material. The coil 5 is a wire that generates a magnetic field. The coil 5 is provided in the core 4. Specifically, the coil 5 is wound around a slot (not shown) formed in the core 4. AC power is supplied to the coil 5 from a power supply device (not shown). The resin part is provided so as to cover part or all of the core 4 and the coil 5. In other words, the core 4 provided with the coil 5 is molded with the resin part. Molding with the resin part will be described later.

[0011] In the illustrated example, the armature 2 has a refrigerant pipe 6 through which a refrigerant that cools the coil 5 passes. The refrigerant pipe 6 is formed of a serpentine pipe. One end of the refrigerant pipe 6 is provided with an inlet 7 for introducing the refrigerant into the refrigerant pipe 6. The other end of the refrigerant pipe 6 is provided with an outlet 8 for discharging the refrigerant from the refrigerant pipe 6. When the armature 2 has the refrigerant pipe 6, the refrigerant pipe 6 is covered with a resin part except for one end and the other end.

[0012] The case 3 is hollow and can accommodate the armature 2 therein. The case 3 has a case body 9, a first cover 10, a first elastic body 11, a second cover 12, and a second elastic body 13.

[0013] The case body 9 is a member that covers the outside of the armature 2. The case body 9 is cylindrical and has open axial ends. In this embodiment, the case body 9 is rectangular. Typically, the case body 9 is rectangular and has a first wall 14, a second wall 15, a third wall 16, and a fourth wall 17.

[0014] The first wall portion 14 faces a magnet plate used as a field pole of the linear motor. The second wall portion 15 is located opposite the first wall portion 14. The second wall portion 15 has a plurality of through holes 18 through which screws pass when attaching the cased armature 1 to a driven object (such as a machine, a unit, or a component). When attaching the cased armature 1 to a driven object, the screws are threaded through the through holes 18 into screw holes formed in the armature 2. In this embodiment, the first wall portion 14 and the second wall portion 15 face each other in the thickness direction of the case 3. One ends of the first wall portion 14 and the second wall portion 15 are connected to each other by a third wall portion 16. The other ends of the first wall portion 14 and the second wall portion 15 are connected to each other by a fourth wall portion 17. In this embodiment, the third wall portion 16 and the fourth wall portion 17 face each other in the width direction of the case 3.

[0015] The corners of the case body 9 are rounded. Specifically, the corners between the first wall 14 and the third wall 16, the corners between the first wall 14 and the fourth wall 17, the corners between the second wall 15 and the third wall 16, and the corners between the second wall 15 and the fourth wall 17 are rounded. In this application, the term "rounded" means that the corners are arc-shaped, resulting in a rounded shape.

[0016] The first lid portion 10 is a plate-shaped member that closes the opening at one axial end of the case body 9 (the upper right side in FIG. 2 ). In this embodiment, the first lid portion 10 has a first lid main body portion 19 and a first insertion portion 20. The first lid main body portion 19 is a portion that closes the opening at one axial end of the case body 9. The first lid main body portion 19 is a substantially rectangular plate-shaped member that is disposed with its plate surface facing the axial direction of the case body 9. The first insertion portion 20 is a portion that is inserted into the opening at one axial end of the case body 9. The first insertion portion 20 is a substantially rectangular plate-shaped member that is provided at the center of the plate surface of the first lid main body portion 19. The first insertion portion 20 protrudes from the first lid main body portion 19 toward the other axial end of the case body 9. In this case, the first insertion portion 20 is provided on the first lid main body portion 19 with its plate surface facing the axial direction of the case body 9. The outer shape of the first insertion portion 20 is smaller than the outer shape of the first lid body portion 19. As a result, the first lid portion 10 has a recessed step on the inside. The step of the first lid portion 10 is the outer peripheral surface of the first insertion portion 20.

[0017] The first lid 10 has an injection port 21 through which resin is injected into the case 3 to form a resin portion covering the core 4, the coil 5, and the refrigerant pipe 6. The injection port 21 penetrates the first lid 10 in the thickness direction. That is, the injection port 21 penetrates the first lid main body 19 in the thickness direction and the first insertion portion 20 in the thickness direction. In this embodiment, the first lid 10 has two injection ports 21, 21. One of the two injection ports 21, 21 is used to actually inject the resin. The other of the two injection ports 21, 21 is used to release air from the case 3 to the outside while the resin is being injected into the case 3. In this embodiment, the first lid 10 has the injection port 21. However, instead of the first lid 10, the second lid 12 (described later) may have the injection port. The number of injection ports 21 is not limited to two.

[0018] The first elastic body 11 is an elastically deformable annular member. Typically, the first elastic body 11 is an O-ring. The first elastic body 11 is provided on the aforementioned step portion of the first cover portion 10 by being fitted onto the first insertion portion 20 of the first cover portion 10.

[0019] The first cover 10 provided with the first elastic body 11 is attached to the case body 9 so as to close the opening at one axial end of the case body 9. Specifically, the first insertion portion 20 is inserted into the opening at one axial end of the case body 9 until the first cover body 19 contacts one axial end of the case body 9. When the first insertion portion 20 is inserted into the case body 9, the first elastic body 11 is positioned between the case body 9 and the first insertion portion 20 in a crushed, deformed state. Therefore, the first cover 10 is attached to the case body 9 by friction between the first elastic body 11 and the case body 9. When the first cover 10 is attached to the case body 9, the first elastic body 11 seals the gap between the first insertion portion 20 and the case body 9. In this way, the first elastic body 11 is a member that seals the gap between the case body 9 and the first cover 10 and attaches the first cover 10 to the case body 9.

[0020] The second lid portion 12 is a plate-shaped member that closes the opening at the other axial end of the case body 9. In this embodiment, the second lid portion 12 is basically configured similarly to the first lid portion 10. That is, the second lid portion 12 includes a second lid main body portion 22 and a second insertion portion (not shown). The second lid main body portion 22 closes the opening at the other axial end of the case body 9. The second lid main body portion 22 is a substantially rectangular plate-shaped member that is disposed with its plate surface facing the axial direction of the case body 9. The second insertion portion is inserted into the opening at the other axial end of the case body 9. The second insertion portion is a substantially rectangular plate-shaped member that is provided at the center of the plate surface of the second lid main body portion 22. The second insertion portion protrudes from the second lid main body portion 22 toward one axial end of the case body 9. In this case, the second insertion portion is provided on the second lid main body portion 22 with its plate surface facing the axial direction of the case body 9. The outer shape of the second insertion portion is smaller than the outer shape of the second lid body portion 22. As a result, the second lid portion 12 has a recessed step on the inside. The step of the second lid portion 12 is the outer peripheral surface of the second insertion portion. In the illustrated example, the second lid portion 12 has through holes 23 through which the inlet 7 and the outlet 8 of the refrigerant pipe 6 pass.

[0021] The second elastic body 13 is an elastically deformable annular member. Typically, the second elastic body 13 is an O-ring. The second elastic body 13 is provided on the aforementioned step portion of the second cover portion 12 by being inserted into the second insertion portion of the second cover portion 12.

[0022] The second cover 12, provided with the second elastic body 13, is attached to the case body 9 so as to close the opening at the other axial end of the case body 9. The second cover 12 is attached to the case body 9 in the same manner as the first cover 10. Specifically, the second insertion portion is inserted into the opening at the other axial end of the case body 9 until the second cover body 22 contacts the other axial end of the case body 9. When the second insertion portion is inserted into the case body 9, the second elastic body 13 is positioned between the case body 9 and the second insertion portion in a crushed, deformed state. Therefore, the second cover 12 is attached to the case body 9 by friction between the second elastic body 13 and the case body 9. When the second cover 12 is attached to the case body 9, the second elastic body 13 seals the gap between the second insertion portion and the case body 9. In this way, the second elastic body 13 is a member that seals the gap between the case body 9 and the second lid portion 12 and also attaches the second lid portion 12 to the case body 9 .

[0023] In this embodiment, the first cover 10 has a first fall prevention portion 24 that prevents the first elastic body 11 from coming off the first insertion portion 20. The first fall prevention portion 24 is plate-shaped. The first fall prevention portion 24 is provided on the first insertion portion 20 of the first cover 10. Specifically, the first fall prevention portion 24 is fixed to both ends of the first insertion portion 20 along the width direction of the case body 9. The first fall prevention portion 24 is fixed to the first insertion portion 20 by screws or the like. When the first fall prevention portion 24 is provided on the first insertion portion 20, the first fall prevention portion 24 is arranged with its plate surface facing the axial direction of the case body 9. When the first fall prevention portion 24 is provided on the first insertion portion 20, the first fall prevention portion 24 extends outward beyond the first insertion portion 20. Therefore, a portion of the first elastic body 11 inserted into the first insertion portion 20 is disposed between the first fall-off prevention portion 24 and the first lid main body portion 19. This prevents the first elastic body 11 from coming off the first insertion portion 20.

[0024] In this embodiment, the second cover portion 12 has a second anti-detachment portion (not shown) that prevents the second elastic body 13 from coming off the second insertion portion. The second anti-detachment portion has a configuration basically similar to that of the first anti-detachment portion 24 and is provided on the second insertion portion in the same manner as the first anti-detachment portion 24. That is, plate-shaped second anti-detachment portions are fixed to both ends of the second insertion portion along the width direction of the case main body 9. Therefore, a portion of the second elastic body 13 inserted into the second insertion portion is disposed between the second anti-detachment portion and the second cover main body portion 22. This prevents the second elastic body 13 from coming off the second insertion portion.

[0025] When single-phase or three-phase AC power is applied to the coil 5 of the cased armature 1 configured as described above, attractive and repulsive forces act between the moving magnetic field generated in the coil 5 and the magnetic field of the magnet plate, providing thrust to the cased armature 1. This allows the cased armature 1 to move linearly along the direction of arrangement of the multiple permanent magnets arranged on the magnet plate. In this way, a linear motor equipped with the cased armature 1 and the magnet plate operates.

[0026] Next, assembly of the case-attached armature 1 of this embodiment will be described. When assembling the case-attached armature 1, the first cover 10 and the second cover 12 may be attached to the case body 9 with the armature 2 disposed in the case body 9. When the second cover 12 is attached to the case body 9, the inlet 7 and the outlet 8 of the refrigerant pipe 6 are exposed to the outside of the case 3 through the through-hole 23 of the second cover 12. Note that the other of the first cover 10 and the second cover 12 may be attached to the case body 9 after the armature 2 is housed in the case body 9 to which one of the first cover 10 and the second cover 12 is attached.

[0027] After the armature 2 is housed in the case 3 in this manner, molten resin is injected into the case 3 through the injection port 21. After the molten resin is injected into the case 3, the molten resin hardens to form a resin portion that covers the core 4, the coil 5, and the refrigerant pipe 6. In this manner, the armature 2 having the resin portion that covers the core 4 and the coil 5 is housed in the case 3.

[0028] In the case of the cased armature 1 of the first embodiment, the first cover portion 10 is attached to the case body 9 by a first elastic body 11, and the second cover portion 12 is attached to the case body 9 by a second elastic body 13. Therefore, according to the cased armature 1 of the first embodiment, welding is not required when assembling the case 3.

[0029] In the case of the cased armature 1 of the first embodiment, the first elastic body 11 and the second elastic body 13 are O-rings. Therefore, according to the cased armature 1 of the first embodiment, the first cover portion 10 and the second cover portion 12 can be easily attached to the case main body 9.

[0030] In the case of the case-equipped armature 1 of the first embodiment, the case 3 has an injection port 21 for molten resin. Therefore, after the core 4 provided with the coil 5 is housed in the case 3, a resin portion covering the core 4 and the coil 5 can be formed.

[0031] In the case of the case-attached armature 1 of the first embodiment, molten resin is injected into the case 3 through the injection port 21. After the molten resin is injected into the case 3, the molten resin hardens and can sandwich the first fall-off prevention portion 24 and the second fall-off prevention portion. Therefore, according to the case-attached armature 1 of the first embodiment, the resin can fix the first cover portion 10 and the second cover portion 12 to the case body 9. That is, the resin can serve as a fixing member that fixes the first cover portion 10 and the second cover portion 12 to the case body 9. Note that the fixing member is not limited to resin and may be, for example, an adhesive. In this manner, the case body 9 and the first cover portion 10, and the case body 9 and the second cover portion 12 can be fixed by the fixing member.

[0032] Next, a case-attached armature 1a according to a second embodiment of the present invention will be described with reference to Fig. 4. Note that components having the same reference numerals as those in the first embodiment have the same functions, and therefore, their description may be omitted below.

[0033] In the first embodiment, the resin portion covering the core 4 and the coil 5 is formed by injecting resin into the case 3 through the injection port 21, but in the second embodiment, the core 4 and the coil 5 are covered in advance by the resin portion 25. In this case, to assemble the case-attached armature 1a, the armature 2 in which the core 4 and the coil 5 are covered by the resin portion 25 is housed in the case main body 9, and then the first lid 10 and the second lid 12 are attached to the case main body 9. Note that in the second embodiment, the first and second fall-off prevention portions 24 and 12 may be omitted.

[0034] In the case of the cased armature 1a of the second embodiment, the core 4 and the coil 5 are covered with the resin portion 25 before being housed in the case 3. Therefore, according to the cased armature 1a of the second embodiment, the armature 2 in which the core 4 and the coil 5 are covered with the resin portion 25 can be easily housed in the case 3.

[0035] Next, a cased armature 1b according to a third embodiment of the present invention will be described with reference to Fig. 5. Components having the same reference numerals as those in the first embodiment have the same functions, and therefore their description may be omitted below. The cased armature 1b of the third embodiment differs from the first embodiment in the configuration of the case 3.

[0036] Before forming the case body 9 of the case-equipped armature 1b of the third embodiment into a cylindrical shape, the third wall portion 16 is divided along a line along the axial direction of the case body 9 so that a portion in the circumferential direction is open. The case body 9 is formed into a cylindrical shape by welding the divided surfaces of the divided third wall portion 16 in a butted state. That is, the third wall portion 16 has a welded portion 26 formed by welding the divided surfaces, which are divided along the plane having the axis of the case body 9 as a boundary.

[0037] In the third embodiment, the third wall portion 16 is divided, but the fourth wall portion 17 may be divided instead of the third wall portion 16. In this case, the fourth wall portion 17 has a welded portion 26 formed by welding the divided surfaces that are divided along a plane having the axis of the case body 9.

[0038] In the case of the case-attached armature 1b of the third embodiment, the welds 26 are provided on the third wall 16 or the fourth wall 17. In conventional cases, the welds are provided at the corners between the first and third walls, the corners between the first and fourth walls, the corners between the second and third walls, and the corners between the second and fourth walls. Therefore, the welds may bulge, making it difficult to ensure flatness in the second wall attached to the machine and the first wall facing the magnet plate. In contrast, in the third embodiment, the welds are not located at the corners of the case body 9, so the above-mentioned problem does not occur.

[0039] In the case of the case-attached armature 1b of the third embodiment, after the case body 9 is formed into a cylindrical shape, the armature 2 is housed in the case 3. That is, in the third embodiment, the welding work is performed with the armature 2 not housed in the case 3, so that the armature 2 is not adversely affected by heat.

[0040] In the case of the cased armature 1b of the third embodiment, the case body 9 has a welded portion 26. Therefore, according to the cased armature 1b of the third embodiment, the cylindrical case body 9 can be formed more easily compared to the case where the case body 9 is formed by extrusion molding.

[0041] Next, a cased armature 1c according to a fourth embodiment of the present invention will be described with reference to Fig. 6. Note that components having the same reference numerals as those in the first embodiment have the same functions, and therefore their description may be omitted below. The cased armature 1c of the fourth embodiment differs from the first embodiment in the configuration of the case 3.

[0042] Before being formed into a cylindrical shape, the case body 9 of the case-equipped armature 1c of the fourth embodiment has the third wall portion 16 and the fourth wall portion 17 divided along a line along the axial direction of the case body 9. As shown in Fig. 6, the case body 9 has a first member 27 covering one thickness direction side of the armature 2 and a second member 28 covering the other thickness direction side of the armature 2. The case body 9 is formed into a cylindrical shape by welding the divided surfaces 29, 29 of the divided third wall portion 16 together in a butted state and by welding the divided surfaces 30, 30 of the divided fourth wall portion 17 together in a butted state. That is, the third wall portion 16 and the fourth wall portion 17 have welded portions 26 formed by welding the divided surfaces, which are separated by a plane including the axis of the case body 9, together.

[0043] In the case of the cased armature 1c of the fourth embodiment, the welded portions 26 are provided on the third wall portion 16 and the fourth wall portion 17. Therefore, according to the cased armature 1c of the fourth embodiment, the welded portions 26 are not located at the corners of the case body 9, so that the flatness of the first wall portion 14 and the second wall portion 15 can be ensured.

[0044] In the case of the case-equipped armature 1c of the fourth embodiment, after the case body 9 is formed into a cylindrical shape, the armature 2 is housed in the case 3. That is, in the fourth embodiment, the welding work is performed with the armature 2 not housed in the case 3, so that the armature 2 is not adversely affected by heat.

[0045] In the case of the cased armature 1c of the fourth embodiment, the case body 9 has a welded portion 26. Therefore, according to the cased armature 1c of the fourth embodiment, the cylindrical case body 9 can be formed more easily compared to the case where the case body 9 is formed by extrusion molding.

[0046] According to at least one of the embodiments described above, the cased armature 1 has the case 3 configured as described above. Therefore, it is possible to provide a cased armature 1 using a case 3 that can reduce the number of welding points.

[0047] Although the present disclosure has been described in detail, the present disclosure is not limited to the individual embodiments described above. Various additions, substitutions, modifications, partial deletions, etc. are possible in these embodiments without departing from the gist of the present disclosure or the spirit of the present disclosure derived from the content of the claims and their equivalents. These embodiments can also be implemented in combination. For example, in the above-described embodiments, the order of each operation and the order of each process are shown as examples and are not limited to these. The same applies when numerical values ​​or mathematical expressions are used in the description of the above-described embodiments.

[0048] For example, in the third and fourth embodiments, a resin portion covering the core 4 and the coil 5 is formed by injecting molten resin into the case 3 through the injection port 21, but in the third and fourth embodiments, the core 4 and the coil 5 may be covered with the resin portion before being placed in the case 3.

[0049] The following supplementary notes are further disclosed regarding the above embodiment: (Supplementary Note 1) The case-equipped armature (1) includes an armature (2) having a core (4) as a main body, a coil (5) provided on the core (4), and a resin portion covering part or all of the core (4) and the coil (5), and a case (3) capable of accommodating the armature (2) therein. The case (3) has a cylindrical case body (9) that covers the outside of the armature (2), a first lid (10) that closes an opening at one axial end of the case body (9), a first elastic body (11) that seals a gap between the case body (9) and the first lid (10) and attaches the first lid (10) to the case body (9), a second lid (12) that closes an opening at the other axial end of the case body (9), and a second elastic body (13) that seals a gap between the case body (9) and the second lid (12) and attaches the second lid (12) to the case body (9). (Supplementary Note 2) In the case-attached armature (1) of Supplementary Note 1, it is preferable that the corners of the rectangular cylindrical case body (9) are rounded. Preferably, the first cover (10) has a first insertion portion (20) inserted into an opening at one axial end of the case main body (9), and the second cover (12) has a second insertion portion inserted into an opening at the other axial end of the case main body (9). The first elastic body (11) and the second elastic body (13) are elastically deformable annular members, and the first elastic body (11) is preferably fitted onto the first insertion portion (20), and the second elastic body (13) is preferably fitted onto the second insertion portion. (Supplementary Note 3) In the case-attached armature (1) in Supplementary Note 1 or Supplementary Note 2, it is preferable that one of the first cover (10) and the second cover (12) has an injection port (21) for injecting a resin that forms the resin portion into the case (3). (Appendix 4) In the case-equipped armature (1) of any one of Appendices 1 to 3, it is preferable that the case body (9) and the first lid portion (10), and the case body (9) and the second lid portion (12) are fixed by fixing members.(Supplementary Note 5) In the case-attached armature (1) of any of Supplementary Notes 1 to 4, the square cylindrical case body (9) preferably has a first wall portion (14) facing a magnet plate used as a field pole of a linear motor, a second wall portion (15) facing the first wall portion (14), a third wall portion (16) connecting one end of the first wall portion (14) and the second wall portion (15) to each other, and a fourth wall portion (17) connecting the other end of the first wall portion (14) and the second wall portion (15) to each other. One or both of the third wall portion (16) and the fourth wall portion (17) preferably have a welded portion (26) formed by welding together divided surfaces separated by a plane having the axis of the case body (9).

[0050] REFERENCE SIGNS LIST 1 Armature with case 2 Armature 3 Case 4 Core 5 Coil 9 Case body 10 First lid 11 First elastic body 12 Second lid 13 Second elastic body 14 First wall 15 Second wall 16 Third wall 17 Fourth wall 20 First insertion portion 21 Inlet 25 Resin portion 26 Welded portion

Claims

1. an armature having a core as a main body, a coil provided in the core, and a resin portion covering part or all of the core and the coil; a case capable of accommodating the armature therein, The case is a cylindrical case body that covers the outside of the armature; a first cover portion that closes an opening at one axial end of the case body; a first elastic body that seals a gap between the case body and the first lid portion and attaches the first lid portion to the case body; a second cover portion that closes an opening at the other axial end of the case body; a second elastic body that seals a gap between the case body and the second lid portion and attaches the second lid portion to the case body.

2. The corners of the rectangular cylindrical case body are rounded, the first cover portion has a first insertion portion that is inserted into an opening at one axial end side of the case body, the second cover portion has a second insertion portion that is inserted into an opening on the other axial end side of the case body, the first elastic body and the second elastic body are elastically deformable annular members, the first elastic body is fitted onto the first insertion portion, 2. The armature with case according to claim 1, wherein the second elastic body is fitted onto the second insertion portion.

3. 3. The armature with case according to claim 1, wherein one of the first cover portion and the second cover portion has an injection port through which a resin for forming the resin portion is injected into the case.

4. 3. The armature with case according to claim 1, wherein the case body and the first lid portion, and the case body and the second lid portion are fixed together by a fixing member.

5. The case body has a rectangular cylindrical shape and includes a first wall portion facing a magnet plate used as a field pole of the linear motor, a second wall portion facing the first wall portion, a third wall portion connecting one end of the first wall portion and one end of the second wall portion, and a fourth wall portion connecting the other end of the first wall portion and one end of the second wall portion, 3. The armature with a case according to claim 1, wherein one or both of the third wall portion and the fourth wall portion has a welded portion formed by welding together divided surfaces that are divided along a plane having an axis of the case main body.