Linear motor, compressor equipped with linear motor, and refrigerator and vehicle air suspension equipped with said compressor

Abstract

To provide a linear motor suitable for reciprocating compressors with asymmetrical load characteristics and capable of improving the bearing life and reducing the total length of a system.SOLUTION: A disclosed linear motor includes: a movable element 2 that has a magnetic pole frame 200 and multiple field magnetic poles 210 provided to the magnetic pole frame 200; and multiple magnetic pole teeth 301 having a winding 5 wound therearound and arranged to sandwich the movable element 2, in which the movable element 2 and the magnetic pole teeth 301 make a relative displacement. The multiple field magnetic poles 210 is constituted by a main magnet 211 placed between the multiple magnetic pole teeth 301 and sub-magnets that are placed at either outer side of the relative displacement directions rather than between the multiple magnetic pole teeth 301. At the other outer side of relative displacement direction, a neck 202 of the magnetic pole frame 200 connected with a bearing 6 is formed.SELECTED DRAWING: Figure 2

Description

[Technical field]

[0001] The present invention relates to a linear motor, a compressor equipped with the linear motor, and a refrigerator and a vehicle air suspension equipped with the compressor. [Background technology]

[0002] A linear motor, which is a thrust generating mechanism, generates thrust in a mover by magnetic force acting between magnetic poles formed on a stator and a mover. As background art in this technical field, linear motors described in JP 2019-154141 A (Patent Document 1) and JP 2018-64412 A (Patent Document 2) are known.

[0003] In both linear motors, two magnetic pole tooth sets consisting of two magnetic pole teeth facing each other with a space in the vertical direction are arranged in the front-to-rear direction to form a stator, and in Patent Document 1, three permanent magnet magnetic poles are arranged in the front-to-rear direction between the upper and lower magnetic pole teeth to form a mover, while in Patent Document 2, two permanent magnet magnetic poles and one soft magnetic pole are arranged in the front-to-rear direction between the upper and lower magnetic pole teeth to form a mover. By making one of the ends of the three mover magnetic poles soft magnetic, the thrust characteristics in the forward and backward directions are asymmetric. This motor is used in combination with a compressor with asymmetric load characteristics in both directions. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] JP 2019-154141 A [Patent Document 2] JP 2018-64412 A Summary of the Invention [Problem to be solved by the invention]

[0005] In the linear motors of Patent Document 1 and Patent Document 2, three mover magnetic poles are arranged in a row, while two armature magnetic poles are arranged in a row in the moving direction of the mover. In Patent Document 1, all three mover magnetic poles are composed of permanent magnets, while in Patent Document 2, some of them are composed of soft magnetic material. In both cases, parts of the mover magnetic poles at both ends protrude outside the ends of the armature magnetic poles, and a piston is connected to one of the mover ends via a connection part, so the length of the entire mover becomes long, and the overall length of the compressor system including the piston becomes long. In addition, if bearings are arranged in front of and behind the mover, the distance between the bearings becomes long because of the long mover, and the bearing load increases due to the increase in the moment acting on the mover, which reduces the bearing life. In addition, if the mover is long, the mover is more likely to bend due to the magnetic attraction force acting on the mover, which may cause the mover to deform, come into contact with the stator, or even be damaged.

[0006] An object of the present invention is to provide a linear motor that is suitable for a compressor having asymmetric reciprocating load characteristics, improves bearing life, and reduces the overall length of the system, and a compressor equipped with the linear motor, as well as a refrigerator and a vehicle air suspension equipped with the compressor. [Means for solving the problem]

[0007] In order to achieve the above object, the present invention provides a magnetic pole frame, a field element having a plurality of field poles provided on the magnetic pole frame, and a winding wound thereon, In the vertical direction In a linear motor in which a plurality of armature poles are provided to sandwich the field element, and the field element and the armature poles are displaced relative to each other, the plurality of field element poles are made up of a main magnet arranged between the plurality of armature poles, and a first sub-magnet arranged on one side of the space between the plurality of armature poles in a relative displacement direction, and a neck portion of the magnetic pole frame connected to a bearing is provided on the other outside in the relative displacement direction. The bearing includes a bearing shaft connected to the neck and moving together with the neck in a relative displacement direction, and a bearing bush in contact with an outer periphery of the bearing shaft. The thickness of the neck in the vertical direction is made smaller than the distance between the armature poles in the vertical direction. It is characterized by the fact that Effect of the Invention

[0008] According to the present invention, it is possible to provide a linear motor that improves the bearing life and reduces the overall length of a system, a compressor equipped with the linear motor, and a refrigerator and a vehicle air suspension equipped with the compressor. Problems, configurations, and effects other than those described above will become apparent from the description of the following embodiments. [Brief description of the drawings]

[0009] [Figure 1] 1 is a perspective view of a linear motor according to a first embodiment. [Diagram 2] 1 is a perspective view showing a cross section perpendicular to the left-right direction of a linear motor according to a first embodiment. [Diagram 3] 1 is a cross-sectional view perpendicular to the left-right direction of a linear motor according to a first embodiment. [Figure 4] 1 is a cross-sectional view perpendicular to the up-down direction of a linear motor according to a first embodiment. [Diagram 5] 3 is a cross-sectional view perpendicular to the up-down direction of a mover according to the first embodiment and a mover according to a comparative example. FIG. [Figure 6] FIG. 4 is a diagram showing the characteristics of the load applied to a piston with respect to the piston position of a compressor. [Figure 7] FIG. 11 is a diagram showing a comparison result of thrust force generated in mover 2 when AC current is applied to windings 5 ​​and when AC current is not applied to windings 5 ​​with respect to the mover position in Example 1 and a comparative example. [Figure 8] FIG. 10 is a diagram showing the waveform of thrust when a direct current is applied to the windings to move the mover in the forward and backward directions (relative displacement directions) when the length of the sub-magnet is changed in the second embodiment. [Figure 9] 13 is a schematic diagram of thrust generated in each mover magnetic pole when a current is applied to the windings and the mover is positioned in the center in the front-rear direction in Example 2. FIG. [Figure 10] 13 is a schematic diagram of thrust generated in each mover magnetic pole when the mover is positioned at the front-to-rear direction frontmost position in the second embodiment. FIG. [Figure 11] 13 is a schematic diagram of thrust generated in each mover magnetic pole when the mover is located at the rearmost position in the front-rear direction in the second embodiment. FIG. [Figure 12]FIG. 13 is a schematic diagram of the thrust generated in the mover when a current is passed through the windings in the conventional example of three magnets and the mover is positioned in the center in the front-to-rear direction. [Figure 13] 13 is a schematic diagram of a thrust force generated in the mover when a current is applied to the windings and the mover is positioned in the center in the front-rear direction in the third embodiment. FIG. [Figure 14] FIG. 11 is a diagram showing the transition of the magnitude of the generated thrust force with respect to the ratio of the lengths of the main magnets and the auxiliary magnets in the third embodiment and the conventional example. [Figure 15] 11 is a cross-sectional view perpendicular to the up-down direction of a mover according to a fourth embodiment. FIG. [Figure 16] 11 is a cross-sectional view perpendicular to the left-right direction of a linear motor according to a fourth embodiment. FIG. [Figure 17] FIG. 11 is a perspective view showing a compressor using a linear motor according to a fifth embodiment of the present invention. [Figure 18] FIG. 18 is a cross-sectional view showing a main part of the compressor shown in FIG. [Figure 19] FIG. 11 is a configuration diagram of a refrigerator according to a sixth embodiment. [Figure 20] FIG. 13 is a configuration diagram of a vehicle air suspension according to a seventh embodiment. DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS

[0010] Hereinafter, an embodiment of the present invention will be described in detail with reference to the accompanying drawings. In a number of embodiments and modifications of each embodiment, similar components are given similar reference numerals and will not be described. For the sake of explanation, the terms front-rear, left-right, and up-down directions that are mutually perpendicular are used, but the direction of gravity does not necessarily have to be downward, and can be parallel to the up, right, left, front or back directions, or other directions.

[0011] In each embodiment and each modified example described below, the front-rear direction corresponds to the drive direction of the mover 2, and the up-down direction corresponds to the direction perpendicular to the magnetic pole face (the face on which the S and N poles are generated) of the field element magnetic pole 210. Also, the front-rear direction of the mover 2 is the longitudinal direction. EXAMPLES

[0012] A linear motor according to a first embodiment of the present invention will be described with reference to Fig. 1 to Fig. 7. Fig. 1 is a perspective view of the linear motor according to the first embodiment. Fig. 2 is a perspective view showing a cross section perpendicular to the left-right direction of the linear motor according to the first embodiment. Fig. 3 is a cross section perpendicular to the left-right direction of the linear motor according to the first embodiment. Fig. 4 is a cross section perpendicular to the up-down direction of the linear motor according to the first embodiment.

[0013] The linear motor 100 is composed of a stator 1 and a mover 2. In the following explanation, the armature side will be described as a stator that is stationary relative to the ground, and the field element side will be described as a mover that moves back and forth relative to the ground, but the relationship between the stator and mover may be reversed. In other words, the linear motor 100 is configured so that the field element and the armature are displaced relative to each other. A bearing 6, a piston 7, and a cylinder 8 are arranged in front of the linear motor 100, forming a compressor that compresses the air inside the cylinder 8.

[0014] <Stator 1> The stator 1 includes an armature 3, end members 4 disposed on the front and rear sides of the armature 3, and a winding 5. The armature 3 has a core 300 made of a soft magnetic material, and the core 300 has a plurality of magnetic pole teeth 301 (armature magnetic poles) on the top and bottom, each of which is wound with a winding 5. The bridge 310 is made of a soft magnetic material or a non-magnetic material, and the plurality of cores 300 are connected by the bridge 310. The armature 3 of this embodiment is configured by arranging two cores 300 in the front-rear direction, but three or more cores 300 may be arranged in the front-rear direction and connected between the plurality of cores 300 by the bridge 310. The end members 4 can be provided in front of the frontmost armature 3 and / or on the rear of the rearmost armature 3.

[0015] <Core 300> The core 300 has magnetic pole teeth 301 arranged opposite to each other with the mover 2 (field element) in between, and arm portions 302 connecting the two magnetic pole teeth 301 on the left and right. The magnetic pole teeth 301 and the arm portions 302 can be formed, for example, by laminating electromagnetic steel sheets in the front-rear direction. A winding 5 is wound around the magnetic pole teeth 301.

[0016] The arm portion 302 is a soft magnetic body extending in the vertical direction on both outer sides in the left-right direction of the winding 5 and the mover 2, and can guide the magnetic flux emitted from the field element magnetic pole 210 and entering the magnetic pole tooth 301 to another magnetic pole tooth 301 that faces the magnetic pole tooth 301 via the mover 2. This allows the core 300 to form a magnetic path that includes the magnetic pole tooth 301, a plurality of field element magnetic poles 210 consisting of a main magnet 211 and a sub-magnet 212 (first sub-magnet) that face the magnetic pole tooth 301, the magnetic pole tooth 301 that faces the field element magnetic pole 210 on the side opposite to the side where the magnetic pole tooth 301 faces, and the arm portion 302. The magnetic flux that passes through this magnetic path is called a transverse magnetic flux.

[0017] <Bridge 310> The bridge 310 can be made of a soft magnetic material or a non-magnetic material. When the bridge 310 is made of a soft magnetic material, it can be a magnetic circuit that passes magnetic flux flowing through adjacent cores 300. The bridge 310 can be made, for example, by laminating stamped electromagnetic steel sheets in the front-to-rear direction. Therefore, the armature 3 in which the bridge 310 is arranged between two cores 300 can form a magnetic path that includes two adjacent cores 300 and field element poles 210 according to the design of the front-to-rear spacing of the field element poles 210, etc. The magnetic flux that passes through this magnetic path is called vertical magnetic flux.

[0018] <End member 4> The end member 4 can be made of a soft magnetic material or a non-magnetic material. The end member 4 is fixed together with the core 300 and the bridge 310 by a fixing member such as a through bolt (not shown) that extends in the front-rear direction. In addition, a support member such as a bearing 6 is disposed on the end member 4 to support the mover 2.

[0019] The mover 2 (field element) has a longitudinal direction in the front-rear direction. The mover 2 has a magnetic pole frame 200 made of a non-magnetic material or a soft magnetic material to which a plurality of permanent magnets are fixed in the front-rear direction, and a field element magnetic pole 210 provided on the magnetic pole frame 200. The mover 2 of this embodiment has two fixed field element magnetic poles 210, and is composed of a main magnet 211 between the cores 300 arranged in a row in the front-rear direction, and a sub magnet 212 arranged in a row behind the main magnet 211. The main magnet 211 is arranged between the plurality of magnetic pole teeth 301, and the sub magnet 212 is arranged on one side of the space between the plurality of magnetic pole teeth 301 in the front-rear direction (relative displacement direction). When three or more cores 300 are arranged in the front-rear direction, the number of main magnets 211 between the cores 300 arranged in the front-rear direction can be increased, but one sub magnet 212 is arranged at the rear end. The field element poles 210 are each magnetized in the up-down direction, and the top surfaces of adjacent field element poles 210 are arranged so that N poles and S poles alternate.

[0020] A bearing 6 is disposed at the front end of the mover 2, and a piston 7 is disposed further ahead of that. Two bearings 6 are disposed at the rear end of the mover 2, and can move relative to the stator 1. The bearings 6 consist of a bearing shaft 600 connected to the mover 2 and moving in the front-rear direction together with the mover 2, and a bearing bush 610 connected to the end member 4 and in contact with the outer periphery of the bearing shaft 600.

[0021] The mover 2 is disposed in the space between the two magnetic pole teeth 301 in the vertical direction and between the two arm portions 302 in the horizontal direction. The field element magnetic pole 210 can be formed in a flat plate shape perpendicular to the vertical direction. That is, in this embodiment, the field element magnetic pole 210 is in a flat plate shape whose width dimension in the horizontal direction and length dimension in the front-rear direction are larger than its thickness dimension in the vertical direction. In this embodiment, the vertical direction is the direction in which the magnetic pole teeth 301 and the field element magnetic pole 210 face each other.

[0022] As described above, in this embodiment, the mover 2 is formed of a field element.

[0023] <Magnetic pole frame 200> 3 and 4, the magnetic pole frame 200 is composed of a body portion 201 into which the field element magnetic pole 210 is fitted, and a neck portion 202 connected to the front bearing 6. The neck portion 202 is disposed on the other outer side of the magnetic pole frame 200 in the front-rear direction (relative displacement direction).

[0024] The body 201 is formed in a ladder shape with a plurality of gaps 203 into which the field element poles 210 are fitted. The field element poles 210 are fitted into the gaps 203, and are fixed to the magnetic pole frame 200 without falling out in the left-right and front-back directions. The magnetic pole frame 200 has edges of the gaps 203 surrounding the field element poles, and supports the field element poles 210. The gaps 203 are formed as through holes that penetrate the magnetic pole frame 200 in the vertical direction, and constitute fitting sections into which the field element poles 210 are fitted in the vertical direction. The field element poles 210 are arranged in the gaps (fitting sections) 203 so as to fill the gaps (fitting sections), and thus positional deviation in the left-right and front-back directions is prevented. Furthermore, positional deviation in the vertical direction is prevented by applying an adhesive to the contact surface between the field element poles 210 and the gaps (fitting sections) 203, for example.

[0025] The thickness A of the neck 202 in the vertical direction is set to be smaller than, for example, the distance B between the magnetic pole teeth 301 in the vertical direction. This allows the bearing shaft 600, which is larger than the distance B between the magnetic pole teeth 301 in the vertical direction, to approach the vicinity of the magnetic pole teeth 301, and the backward stroke of the mover 2 can be increased.

[0026] The width D of the neck 202 is made smaller than, for example, the width E of the hole of the end member 4 in which the bearing bush is housed. This allows the neck 202 to be inserted into the hole of the end member 4, and the forward stroke of the mover 2 can be increased.

[0027] The length of the neck portion 202 should be set to such an extent that the bearing shaft 600 does not come into contact with the magnetic pole teeth 301 when the mover 2 is located at the rearmost position, and that the body portion 201 of the mover 2 does not come into contact with the end member 4 when the mover 2 is located at the frontmost position. This allows the stroke of the mover 2 to be increased.

[0028] The magnetic pole frame 200 may be formed of a soft magnetic material or a non-magnetic material. Note that the air gap (insertion portion) 203 may be configured as a concave portion into which the field pole 210 can be attached. This concave portion is formed in a concave shape on one end surface of the magnetic pole frame 200 in the vertical direction. This concave portion can also be regarded as a kind of air gap (insertion portion) into which the field pole 210 is inserted.

[0029] <Field pole 210> The field pole 210 may be composed of a rare earth magnet such as a neodymium magnet, or a permanent magnet made of other materials such as a ferrite magnet may be used. Also, a part of the field poles 210 may be formed of a soft magnetic material.

[0030] <Comparison of thrust characteristics of linear motors> FIG. 5 is a cross-sectional view perpendicular to the vertical direction of the mover according to Example 1 and the mover according to the comparative example. FIG. 6 is a diagram showing the load characteristics applied to the piston with respect to the piston position of the compressor. FIG. 7 is a diagram showing the comparison result of the thrust generated in the mover 2 when an alternating current is passed through the winding 5 and when it is not passed through, with respect to the mover position in Example 1 and the comparative example.

[0031] In FIG. 5, the mover 2 according to Example 1 consists of one main magnet 211 and one sub-magnet 212, and the distance (length) between the bearing shafts 600 in the front-rear direction (relative displacement direction) is L1. On the other hand, the mover 2 according to the comparative example consists of one main magnet 211 and two sub-magnets 212, and the distance (length) between the bearing shafts 600 in the front-rear direction (relative displacement direction) is L2. From FIG. 5, L1 < L2, and in this embodiment, the distance (length) between the bearing shafts 600 in the front-rear direction can be shortened, the moment force applied to the mover 2 can be reduced, and the load applied to the bearing can be reduced. As a result, the life of the bearing can be improved.

[0032] As can be seen from Fig. 6, when the piston is pushed in, the load increases as the pressure inside the cylinder increases, and when the desired pressure is reached and the discharge valve 900 is opened, the load becomes constant. On the other hand, when the piston is pulled back, the load decreases as the pressure inside the cylinder decreases, and when the pressure inside the cylinder matches the pressure on the suction side, the suction valve 910 is opened and the load becomes zero. In this way, the load applied to the compressor piston is mainly in the piston pushing direction, and has asymmetric characteristics with respect to the front-to-rear direction.

[0033] 7, in the case of three magnets as a comparative example, the field element poles 210 are arranged symmetrically in the front-to-rear direction, so the average thrust value when not energized is zero, and the magnitude of the thrust when energized is symmetric in the front-to-rear direction. Therefore, in order to handle the load that is asymmetric in the front-to-rear direction described above, it is necessary to reduce the thrust when the piston is pulled back, and special control or circuitry is required to pass asymmetric currents back and forth.

[0034] On the other hand, in the case of the two magnets of this embodiment, the field element magnetic poles 210 are arranged asymmetrically in the front-to-rear direction, so the average thrust value when no current is applied is positive in the front direction, and the magnitude of the thrust when current is applied is asymmetric in the front-to-rear direction. Therefore, no special control or circuit is required to deal with the load that is asymmetric in the front-to-rear direction as described above, and a current that is symmetric in both directions can be applied.

[0035] According to this embodiment, the bearing life can be improved and the overall length of the system can be reduced. EXAMPLES

[0036] A linear motor according to a second embodiment of the present invention will be described with reference to Figs. 8 to 11. Fig. 8 is a diagram showing the waveform of the thrust when a DC current is passed through the winding to move the mover in the front-rear direction (relative displacement direction) when the length of the sub-magnet is changed in the second embodiment. In Fig. 8, the length of the sub-magnet in the front-rear direction is changed to 14 mm, 20 mm, and 26 mm. As shown in Fig. 8, the point at which the thrust crosses zero in the forward direction differs depending on the length of the sub-magnet in the front-rear direction, and the longer the length, the further the zero-cross point extends in the forward direction. Since the thrust acts in the rear direction when the zero-cross point is exceeded, the forward stroke can be limited by this zero-cross point.

[0037] The above will be described with reference to Fig. 9 to Fig. 11. Fig. 9 is a schematic diagram of thrust generated at each mover magnetic pole when current is applied to the windings and the mover is located at the center in the front-to-rear direction in the second embodiment, which corresponds to position B in Fig. 8. Fig. 10 is a schematic diagram of thrust generated at each mover magnetic pole when the mover is located at the front-to-rear direction ...

[0038] 9, the pole pitch in the front-rear direction of the magnetic pole teeth 301 is τp1, the pole pitch in the front-rear direction of the field component pole 210 is τp2, the distance from the center of the front magnetic pole teeth 301 to the center of the main magnet 211 is τp1 / 2, the distance from the center of the rear magnetic pole teeth 301 to the center of the sub magnet 212 is τx, and the distance from the tip of the piston 7 to the inner wall of the cylinder is Su. When a current is applied to the winding at this time, N and S poles are excited at the tip of the magnetic pole teeth 301 as shown in the figure, and a forward thrust as indicated by the arrows is generated in each magnet due to interaction with the magnetic poles of the main magnet 211 and the sub magnet 212.

[0039] Figure 10 shows the position where the mover has moved forward by τu, which corresponds to position C in Figure 8. The center of the main magnet 211 and the center of the sub-magnet 212 are located between the centers of the two magnetic pole teeth 301, and the thrust generated in each magnet is in the opposite direction and cancels out, resulting in zero thrust. The position of the mover at this time is expressed by the following equation.

[0040] τu = (τp1 / 2 + τx) / 2 (1) In a compressor, if the position where the piston collides with the cylinder wall is the stroke upper limit position Su, then by setting u to be greater than the above-mentioned thrust generation upper limit position τu, it is possible to avoid the piston collision and prevent piston damage. Su>(τp1 / 2+τx) / 2 (2) Solving this for τx gives us τx<2Su-τp1 / 2 (3) The length of the sub-magnet 212 for the desired stroke can be determined by the above formula. τp2=τp1 / 2+τx (4) The following relationship can be derived from equations (3) and (4):

[0041] τp2<2Su (5) In other words, it is preferable that the pole pitch τp2 in the front-rear direction of the field element poles 210 is less than twice the stroke upper limit position Su.

[0042] Fig. 11 shows the state when the mover is at the rearmost position in the front-rear direction, which corresponds to position A in Fig. 8. Since the sub-magnets 212 protrude outside the magnetic pole teeth 301, the thrust is affected only by the main magnets 211 and is not dependent on the length of the sub-magnets 212.

[0043] According to this embodiment, when the mover is located at the rearmost position in the front-rear direction, the effect of the sub-magnets on the thrust force can be suppressed. EXAMPLES

[0044] A linear motor according to a third embodiment of the present invention will be described with reference to Figs. 12 to 14. Fig. 12 is a schematic diagram of thrust generated in the mover when a current is passed through the windings and the mover is positioned at the center in the front-rear direction in the case of three magnets as a conventional example. Fig. 13 is a schematic diagram of thrust generated in the mover when a current is passed through the windings and the mover is positioned at the center in the front-rear direction in the third embodiment. Fig. 14 is a diagram showing the transition of the magnitude of thrust generated with respect to the ratio of the lengths of the main magnet and the auxiliary magnet in the third embodiment and the conventional example.

[0045] 12 and 13, the pole pitch in the front-rear direction of the magnetic pole teeth 301 is τp1, the pole pitch of the main magnet 211 is τm1, and the pole pitch of the sub magnet is τm2. Note that τp1=23.5 here. Figure 14 shows the transition of the magnitude of thrust when the ratio of the lengths of τm1 and τm2 is changed.

[0046] In the case of three magnets as a comparative example, the thrust is maximum when τm1=23.5 and τm2=20, and there is a relationship of τm1=τp1 at this time. On the other hand, in the case of two magnets as the present embodiment, the thrust is maximum when τm1=25.5 and τm2=19, and at this time, the pole pitch τm1 of the main magnet 211 is longer than the pole pitch τp1 of the multiple armature poles (τm1>τp1). Therefore, in the case of three magnets as a comparative example, the thrust can be maximized by making τm1=τp1, whereas in the case of two magnets as the present embodiment, the thrust can be maximized by making τm1>τp1.

[0047] According to this embodiment, the forward thrust can be increased, and the length of the linear motor in the front-rear direction can be shortened. EXAMPLES

[0048] A linear motor according to a fourth embodiment of the present invention will be described with reference to Fig. 15 and Fig. 16. Fig. 15 is a cross-sectional view perpendicular to the up-down direction of a mover according to the fourth embodiment. Fig. 16 is a cross-sectional view perpendicular to the left-right direction of the linear motor according to the fourth embodiment.

[0049] The configuration of the fourth embodiment is the same as that of the first embodiment except for the following points, and the configuration described in the first embodiment can be adopted except for the configuration according to the present embodiment.

[0050] The neck portion 202 of the mover 2 in this embodiment is provided with a gap 203 into which a second sub-magnet 213, which is shorter in the left-right direction than the main magnet 211 and the sub-magnet 212, is fitted. The second sub-magnet 213 is arranged in the gap 203 (fitting portion) so as to fill the gap 203 (fitting portion), thereby preventing misalignment in the left-right direction and the front-rear direction. Also, misalignment in the up-down direction is prevented by applying an adhesive to the contact surface between the sub-magnet 212 and the gap 203 (fitting portion). The sub-magnet 212 and the second sub-magnet 213 are provided asymmetrically with respect to the center position of the main magnet 211 in the front-rear direction (relative displacement direction).

[0051] The second sub-magnet 213 can improve the thrust when the mover 2 is driven backward, and can be applied when a load is also applied in the backward direction. For example, as shown in Fig. 16, by arranging a piston 7 and a cylinder 8 on both sides of the mover 2 in the front-rear direction, it can be used as a so-called two-stage compressor in which one cylinder compresses to an intermediate pressure and the other cylinder compresses to the maximum pressure.

[0052] The diameter of the piston 7 and the cylinder 8 disposed in the rear direction is smaller than that of the piston 7 and the cylinder 8 disposed in the front direction. EXAMPLES

[0053] Fig. 17 is a perspective view showing a compressor using a linear motor according to a fifth embodiment of the present invention, and Fig. 18 is a cross-sectional view showing a main part of the compressor shown in Fig. 17.

[0054] The compressor 1000 of this embodiment can be used as a gas compressor that compresses air or a refrigerant, and has a resonant spring 400 provided on one side of the armature 3 in the reciprocating direction of the movable member 2, a piston (disposed in a cylinder 8, not shown) provided on the other side of the armature 3, the cylinder 8, solenoid valves 1400 (1400A, 1400B), an exhaust valve 1500, a dryer 1600, and an inverter 1700.

[0055] In the compressor 1000 of this embodiment, the piston drive motor is configured as a linear motor, and the mover 2 is in the shape of a flat plate (plate). The mover 2 also protrudes further rearward from the rear end of the end member 4. The linear motor is one of the linear motors of the first to fourth embodiments.

[0056] A casing 1800 that houses the armature 3 and the resonance spring 400 is attached to the cylinder 8. In this embodiment, the end member 4 is used as the front face of the casing 1800, but a member that constitutes the front face of the casing 1800 may be provided in front of the end member 4. That is, instead of using the end member 4 as the front face member of the casing 1800, a front face member may be provided separately from the end member 4.

[0057] The casing 1800 is configured with a cylindrical side surface (side surface member) 1810 and a rear surface (rear surface member, bottom surface member) 1820, which are separate bodies, and the rear surface 1820 is fixed to the cylinder 8 via a base plate 1900 by an insertion member 1830 extending in the front-rear direction. As a result, the side surface 1810 is sandwiched between the rear surface 1820 and the cylinder 8.

[0058] An electrode protrudes forward from the casing 1800 side, and one end of the electrode is electrically connected to the lead-out end of the winding 5. The other end of the electrode passes through a through-hole (not shown) formed in the base plate 1900 and is inserted into the inverter 1700, and is electrically connected to the internal inverter circuit.

[0059] The base plate 1900 is provided with a gas intake / discharge port 1910. Two solenoid valves 1400A and 1400B are attached to the base plate 1900, and two through holes (gas passages) 1920a and 1920b through which gas flows are provided corresponding to the solenoid valves 1400A and 1400B. The solenoid valves 1400A and 1400B are three-way valves, and constitute gas intake / discharge valves. When one solenoid valve 1400A is in an intake state, the other solenoid valve 1400b is in a discharge state. In the intake state, the one solenoid valve 1400A flows gas sucked from the intake / discharge port 1910 into the inside of the casing 1800 through the through hole 1920a. At this time, the other solenoid valve 1400B is in a discharge state, and blocks the flow of gas through the through hole 1920b.

[0060] The gas that flows into the inside of the casing 1800 through the solenoid valve 1400A flows through the gaps between the movable element 2 and the end member 4 and the base plate 1900, into the inside of the cylinder 8, and flows through the cylinder 8 to the dryer 1600. The gas is then discharged from the dryer 1600 through the other solenoid valve 1400B. When the suction / discharge states of the solenoid valves 1400A and 1400B are switched, the gas flows in the reverse direction to the above-mentioned path. The cylinder 8 compresses the gas that flows in as necessary. On the side of the base plate 1900 where the through hole 1920b is provided, a suction / discharge port (not shown) is provided at a position corresponding to the suction / discharge port 1910.

[0061] A dryer 1600 is attached to the cylinder head 8A of the cylinder 8 in a state in which it can communicate with the inside of the cylinder 8.

[0062] According to this embodiment, it is possible to provide a compressor that can increase the forward thrust force, and can reduce the length of the linear motor in the forward / rearward direction, thereby preventing an increase in size. EXAMPLES

[0063] Fig. 19 is a configuration diagram of a refrigerator according to Example 6. Refrigerator 2001 is provided with refrigerator compartment door 2002a that opens like a double door divided into left and right on the front side of refrigerator compartment 2002, and is provided with pull-out ice compartment door 2003a, upper freezer compartment door 2004a, lower freezer compartment door 2005a, and vegetable compartment door 2006a on the front sides of ice compartment 2003, upper freezer compartment 2004, lower freezer compartment 2005, and vegetable compartment 2006, respectively.

[0064] A machine room 2020 is provided on the rear side of the vegetable room 2006, and a compressor 2024 is arranged in the machine room 2020. An evaporator room 2008 is provided on the rear sides of the ice-making room 2003, the upper freezer room 2004, and the lower freezer room 2005, and an evaporator 2007 is provided in the evaporator room 2008. In the refrigerator 2001, in addition to the compressor 2024 and the evaporator 2007, a radiator (not shown), a capillary tube serving as a pressure reducing means, a three-way valve, and the like are connected by refrigerant piping to form a refrigeration cycle 2030.

[0065] In the present embodiment, the linear motor 100 according to any one of the above-described embodiments is adopted for the compressor 2024 constituting the refrigeration cycle 2030 of the refrigerator 2001. For example, the compressor 1000 according to the fifth embodiment may be adopted as the compressor 2024. This can prevent the compressor 2024 constituting the refrigeration cycle 2030 from becoming large. It is then possible to secure a large space for the refrigerator compartment and the freezer compartment, and it is possible to provide a large-capacity refrigerator without increasing the external dimensions. EXAMPLES

[0066] 20 is a configuration diagram of a vehicle air suspension according to Example 7. In this example, a vehicle air suspension is mounted on a vehicle such as a four-wheeled automobile.

[0067] The vehicle body 3002 constitutes the body of the vehicle 3001. A total of four wheels 3003 consisting of left and right front wheels and left and right rear wheels are provided on the underside of the vehicle body 3002. The air suspension 3004 includes four air springs 3005 respectively provided between the vehicle body 3002 and each wheel 3003, an air compressor 3006, a valve unit 3008, and a controller 3011. The air suspension 3004 adjusts the vehicle height by supplying and discharging compressed air from the air compressor 3006 to each air spring 3005.

[0068] In this embodiment, the linear motor 100 of any one of the above-mentioned embodiments is used as a drive motor for the air compressor 3006. For example, the compressor 1000 of the fifth embodiment may be used as the air compressor 3006. The air compressor 3006 is connected to a valve unit 3008 through a supply / exhaust pipe (piping) 3007. The valve unit 3008 is provided with four supply / exhaust valves 3008a each made of an electromagnetic valve, which are provided for each wheel 3003. A branch pipe (piping) 3009 is provided between the valve unit 3008 and the air spring 3005 of each wheel 3003. The air spring 3005 is connected to the air compressor 3006 through the branch pipe 3009, the supply / exhaust valve 3008a, and the supply / exhaust pipe 3007. The valve unit 3008 opens and closes the supply / exhaust valves 3008a in response to signals from the controller 3011, thereby supplying and discharging compressed air to and from each air spring 3005, thereby adjusting the vehicle height.

[0069] In this embodiment, it is possible to prevent the air compressor 3006 constituting the air suspension 3004 from becoming large. Furthermore, it is possible to reduce the space required for mounting the air compressor 3006 in the vehicle 3001, thereby increasing the degree of freedom in the arrangement of the air compressor 3006.

[0070] [Other aspects] In each embodiment, a moving magnet type in which the armature 3 is fixed and the field element (mover 2) moves has been exemplified, but a moving coil type in which the field element is fixed and the armature 3 moves may also be used.

[0071] Further, instead of providing the magnetic pole teeth 301 on both the upper and lower sides of the mover 2, a configuration in which the magnetic pole teeth 301 are provided on one side in the upper or lower direction of the mover 2 may be adopted. In this case, one end of the arm portion 302 can contact the floor surface of the soft magnetic material to support the core 300.

[0072] Furthermore, the magnetic pole teeth 301, the arm portion 302, and the bridge 310 may be formed by laminating amorphous metals, or may be formed of powder magnetic cores. When amorphous metals are used, there is an effect of reducing iron loss generated in the magnetic pole teeth 301, the arm portion 302, and the bridge 310, and when powder magnetic cores are used, they can be formed into any three-dimensional shape.

[0073] Also, the lamination direction of the electromagnetic steel sheets can be configured to be the left-right direction instead of the front-back direction. In that case, by configuring the core 300 and the bridge 310 as an integral unit, the magnetic flux from the core 300 through the bridge 310 to the adjacent core 300 can pass within the plane of the electromagnetic steel sheets, thereby reducing the magnetic resistance and improving the thrust of the linear motor. Furthermore, by configuring an armless linear motor in which the arm portion 302 is eliminated, the weight of the linear motor can be reduced.

[0074] The present invention can be applied to various devices that relatively move a stator 1 and a mover 2, in addition to motors (linear motors). For example, the same effects can be obtained when used in generators, compressors, electromagnetic suspensions, positioning devices, etc.

[0075] The present invention is not limited to the above-described embodiments, but includes various modified examples. For example, the above-described embodiments have been described in detail to clearly explain the present invention, and are not necessarily limited to those including all of the configurations. It is also possible to replace a part of the configuration of one embodiment with the configuration of another embodiment, and it is also possible to add the configuration of another embodiment to the configuration of one embodiment. It is also possible to add, delete, or replace a part of the configuration of each embodiment with another configuration. [Explanation of symbols]

[0076] Reference Signs List 1... stator, 2... mover (field element), 3... armature, 4... end member, 5... winding, 6... bearing, 7... piston, 8... cylinder, 100... linear motor, 200... pole frame, 201... body, 202... neck, 203... gap, 210... field element pole, 211... main magnet, 212... auxiliary magnet, 213... second auxiliary magnet, 300... core, 301... pole tooth (armature pole), 302... arm portion, 310... bridge, 600... bearing shaft, 610... bearing bush, 900... discharge valve, 910... suction valve

Claims

1. A linear motor including a magnetic pole frame, a field element having a plurality of field poles provided on the magnetic pole frame, a plurality of armature poles around which a winding is wound and which are provided to sandwich the field element in the vertical direction, and the field element and the armature poles are displaced relative to each other, the plurality of field element magnetic poles are comprised of a main magnet arranged between the plurality of armature magnetic poles, and a first sub-magnet arranged on one side outside the spaces between the plurality of armature magnetic poles in a relative displacement direction, and a neck portion of the magnetic pole frame connected to a bearing is provided on the other outside in the relative displacement direction, the bearing includes a bearing shaft connected to the neck portion and moving together with the neck portion in a relative displacement direction, and a bearing bush in contact with an outer circumferential side of the bearing shaft, A linear motor characterized in that the thickness of the neck in the vertical direction is smaller than the distance between the armature poles in the vertical direction.

2. 2. The linear motor according to claim 1, A linear motor, characterized in that the pole pitch of the main magnet is longer than the pole pitch of the plurality of armature poles.

3. 2. The linear motor according to claim 1, A linear motor comprising a second sub-magnet in the neck portion.

4. 4. The linear motor according to claim 3, A linear motor, characterized in that the first sub-magnet and the second sub-magnet are provided asymmetrically with respect to a center position in a relative displacement direction of the main magnet.

5. A compressor including a cylinder, a piston reciprocating inside the cylinder, and a drive motor for driving the piston, A compressor comprising the linear motor according to any one of claims 1 to 4 as the drive motor.

6. A refrigerator that has a refrigerator compartment and a freezer compartment and is cooled by a refrigeration cycle operated by driving a compressor, A refrigerator comprising the compressor according to claim 5 as the compressor.

7. An air suspension for a vehicle is provided on a vehicle, the air suspension comprising an air spring provided between a vehicle body and a wheel, and an air compressor for supplying and discharging compressed air to the air spring, 6. An air suspension for a vehicle, comprising the compressor according to claim 5 as the air compressor.

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