JP2023103600A - Linear motor and electric suspension device equipped with the same - Google Patents

Abstract

To provide a linear motor that suppresses reduction in thrust and suppresses temperature rise.SOLUTION: The linear motor has an armature 8 having teeth 2 and a coil 5 included on the teeth 2 and a permanent magnet 10 provided on the outer circumferential side of the armature 8. The armature 8 and the permanent magnet 10 move relative to each other. A slit 7 is included in the teeth 2 to increase the resistance value of an eddy current path flowing in the teeth 2. The slit 7 is arranged to extend from the inner circumferential side of the teeth to the outer circumferential side.SELECTED DRAWING: Figure 1

Description

The present invention relates to a linear motor and an electric suspension device having the same.

As a suspension provided with a linear motor, there is a technique described in Patent Document 1, for example.

The suspension described in Patent Document 1 includes a bottomed cylindrical outer cylinder having a magnet on the inner peripheral side, a movably inserted into the outer cylinder, one end extending from the outer cylinder, and an outer periphery on the other end side. a hollow first rod having an armature on one side; a second rod having one end slidably fitted to the inner peripheral side of the first rod and the other end fixed to the bottom of the outer cylinder; It is composed of A gap is formed between the inner periphery of the first rod on one end side and the outer periphery of the second rod. Wiring is arranged in the clearance, one end of which is connected to the armature and the other end of which extends to the outside.

JP 2013-29159 A

The suspension of Patent Document 1 is composed of a bottomed cylindrical outer cylinder having a magnet on the inner peripheral side and a linear motor in which an armature inserted inside the outer cylinder is relatively driven. A linear motor has a permanent magnet on the outer peripheral side and a magnetic outer cylinder that circulates the magnetic flux of the permanent magnet, and an armature made up of coils and teeth is arranged inside the outer cylinder. In this structure, a permanent magnet that can be made thin (a structure with small radial dimensions) and an outer cylinder made of a magnetic material are arranged, and by arranging coils and teeth with large radial dimensions, the gap surface It is possible to dispose (the opposing surface of the permanent magnet and the armature) on the outer peripheral side, and a large thrust force can be obtained.

In general, the armature consists of magnetic teeth and a magnetic path so as to surround the coil, so the dimension in the radial direction is inevitably large. For this reason, in a structure in which the armature is arranged on the outer peripheral side, the gap surface is arranged on the inner diameter side, so the area of the gap surface becomes small, and the thrust that can be obtained is small. Therefore, a large thrust force can be obtained by providing a permanent magnet and a magnetic outer cylinder for returning the magnetic flux of the permanent magnet on the outer peripheral side, and arranging an armature composed of a coil and teeth inside the permanent magnet.

However, the magnetic material that surrounds the armature coil in a U-shape is disk-shaped, and the cross-sectional area of the magnetic flux path in the magnetic material decreases toward the inner circumference, so magnetic flux saturation is likely to occur. , the magnetic flux density increases. The magnetic flux density increases toward the inner circumference, and the loss generated by the power of the magnetic flux density B in the magnetic material increases, the thrust of the linear motor decreases, and the temperature of the magnetic material in the center of the armature increases. I had a problem.

SUMMARY OF THE INVENTION An object of the present invention is to solve the above problems and to provide a linear motor that suppresses reduction in thrust and temperature rise, and an electric suspension device having the same.

In order to achieve the above object, the present invention has an armature having teeth and coils provided on the teeth, permanent magnets provided on the outer peripheral side of the armature, and the armature and the permanent magnets are provided. is relatively moved, wherein the teeth are provided with high resistance portions that increase the resistance value of the eddy current path flowing through the teeth.

ADVANTAGE OF THE INVENTION According to this invention, the linear motor which suppressed the fall of a thrust and the rise of a temperature, and an electric suspension apparatus provided with the same can be provided.

1 is a schematic diagram showing an example of a linear motor according to Example 1 of the present invention; FIG. 1 is an external perspective view of an armature according to Example 1 of the present invention; FIG. It is the front view which looked at the linear motor concerning Example 1 of this invention from the Z direction. It is the back view which looked at the linear motor which concerns on Example 1 of this invention from the Z direction. 1 is a schematic side view of a linear motor 1 according to Example 1 of the present invention cut along a YZ plane; FIG. FIG. 4 is a diagram showing the distribution of loss at a certain moment when a three-phase alternating current is passed through six coils 5; FIG. 4 is a diagram comparing the ratio of eddy current loss with and without slits 7 using magnetic field analysis. It is a schematic diagram which shows an example of the linear motor based on Example 2 of this invention. FIG. 7 is an external perspective view of an armature according to Example 2 of the present invention; It is the back view which looked at the linear motor based on Example 2 of this invention from the Z direction. It is the front view which looked at the linear motor which concerns on a comparative example from the Z direction. FIG. 10 is a schematic diagram showing an example of a linear motor according to Example 3 of the present invention; FIG. 8 is an external perspective view of an armature according to Example 3 of the present invention; It is the back view which looked at the linear motor based on Example 3 of this invention from the Z direction. FIG. 5 is a schematic diagram showing an example of a linear motor according to Example 4 of the present invention; FIG. 11 is an external perspective view of an armature according to Example 4 of the present invention; It is the back view which looked at the linear motor based on Example 4 of this invention from the Z direction. FIG. 11 is an external perspective view of an armature according to an application example of Example 4 of the present invention; FIG. 11 is a rear view of a linear motor according to an application example of Example 4 of the present invention, viewed from the Z direction; FIG. 11 is a schematic diagram showing an example of a linear motor according to Example 5 of the present invention; FIG. 11 is an external perspective view of an armature according to Example 5 of the present invention; FIG. 11 is a schematic side view of the linear motor 1 according to Example 5 of the present invention cut along the YZ plane. FIG. 11 is a schematic diagram showing an example of a linear motor according to an application example of Example 5 of the present invention; FIG. 11 is an external perspective view of an armature according to an application example of Example 5 of the present invention; FIG. 11 is a schematic diagram showing an example of a linear motor according to Example 6 of the present invention; FIG. 11 is an external perspective view of an armature according to Example 6 of the present invention; It is the back view which looked at the linear motor based on Example 6 of this invention from the Z direction. FIG. 11 is a schematic diagram showing an example of a linear motor according to Application Example 1 of Example 6 of the present invention; FIG. 11 is an external perspective view of an armature according to Application Example 1 of Example 6 of the present invention; FIG. 11 is a rear view of a linear motor according to Application Example 1 of Embodiment 6 of the present invention, viewed from the Z direction; FIG. 11 is a schematic diagram showing an example of a linear motor according to Application Example 2 of Example 6 of the present invention; FIG. 11 is an external perspective view of an armature according to Application Example 2 of Example 6 of the present invention; FIG. 11 is a rear view of a linear motor according to Application Example 2 of Embodiment 6 of the present invention, viewed from the Z direction; FIG. 11 is a configuration diagram of an electric suspension device equipped with a linear motor according to Embodiment 7 of the present invention;

Hereinafter, embodiments of the present invention will be described with reference to the accompanying drawings. Similar components are denoted by similar reference numerals, and similar descriptions are not repeated.

The various constituent elements of the present invention do not necessarily have to be independent entities, and one constituent element may consist of a plurality of members, a plurality of constituent elements may consist of one member, a certain constituent element may part of a component, part of one component overlaps part of another component, and so on.

In this embodiment, an example of a linear motor applied to an electric suspension device will be described. FIG. 1 is a schematic diagram showing an example of a linear motor according to Example 1 of the present invention.

A linear motor has an armature that reciprocates inside a cylindrical outer cylinder. The axial direction in which the armature moves is the Z direction, the direction perpendicular to the Z direction is the Y direction, and the direction perpendicular to the Z and Y directions is the X direction.

The schematic diagram of FIG. 1 is a diagram of the linear motor 1 cut along the YZ plane. The linear motor 1 shown in FIG. 1 is an example of a linear motor having a five-pole, six-slot configuration in which six coils or teeth are arranged for five permanent magnets. The combination of permanent magnets, coils, and teeth is an example, and the combination is not limited to this combination. For example, any combination of 7 poles and 6 slots, 10 poles and 12 slots, 8 poles and 9 slots can be applied if the same effect can be obtained.

An armature 8 composed of a coil 5 and teeth 2 (core) is linearly driven relative to a member on the secondary side of a permanent magnet 10 provided inside an outer cylinder 20 composed of a magnetic material. A motor 1 is constructed. The armature 8 and the secondary side member are connected to the tire side (not shown) and the vehicle body side (not shown) via rods (not shown) or the like to form an electric suspension device that suppresses vibrations on the vehicle body side. Here, the coil 5 of the linear motor 1 is normally connected to a three-phase inverter (not shown) of U-phase, V-phase, and W-phase, and by controlling the three-phase current, the linear motor 1 moves in the axial direction ( Z direction) thrust is generated to suppress vibration. When a current is passed through the coil 5 of each phase, a loss occurs in the magnetic material near the coil where the current changes greatly. In the linear motor 1 of this embodiment, teeth 2 are made of hollow convex magnetic bodies with through holes 3 formed in the center, and a plurality of teeth 2 are arranged in the Z direction to form an armature 8 .

FIG. 2 is an external perspective view of the armature according to Example 1 of the present invention. FIG. 3 is a front view of the linear motor according to Example 1 of the present invention as seen from the Z direction. FIG. 4 is a rear view of the linear motor according to the first embodiment of the present invention as seen from the Z direction. FIG. 5 is a schematic side view of the linear motor 1 according to Example 1 of the present invention cut along the YZ plane. The armature 8 is composed of a plurality of coils 5 and teeth 2 (core). The tooth 2 includes a protruding portion 2a protruding in the axial direction (Z direction) and a flat plate portion 2b extending radially outward (peripheral side) from the protruding portion 2a. A through hole 3 penetrating in the axial direction (Z direction) is formed on the inner peripheral side of the projecting portion 2a.

The teeth 2 (core) of the armature 8 are provided with slits 7 (notches) arranged so as to extend from the inner peripheral side to the outer peripheral side. The slit 7 is formed from the projecting portion 2a to the flat plate portion 2b. Also, the slits 7 function as high resistance portions that increase the resistance value of the eddy current path flowing through the teeth 2 (core), as will be described later. Although the number of slits 7 is six in this embodiment, it is not limited to this number. If the number of slits is small, the loss suppression effect is small, but if the number of slits is one or more, the loss suppression effect can be obtained.

As shown in FIGS. 3 and 4, the slit 7 formed from the projecting portion 2a to the flat plate portion 2b is provided from the inner peripheral side of the tooth 2 (core) and has a depth that allows the coil 5 to be seen. . That is, as shown in FIG. 5, let Rc be the distance from the center O of the tooth 2 to the inner peripheral side of the recess of the tooth into which the coil 5 is inserted, and let Rc be the distance from the center O of the tooth 2 to the outermost periphery of the slit 7. When Rs, there is a relationship such that the distance Rs is greater than Rc (Rs>Rc). That is, the coil 5 can be seen through the slit 7 . By doing so, the cooling medium (for example, cooling air, cooling oil, cooling water, coolant, etc.) is enclosed in the hole in the center of the slit 7 or is flowed from one direction, so that the cooling medium directly transfers heat from the coil 5. can be taken away and cooled.

FIG. 6 is a diagram showing the distribution of loss at a certain moment when a three-phase alternating current is passed through six coils 5. As shown in FIG. Since the magnetic path area of the tooth 2 (core) increases toward the outer diameter side, the magnetic flux density decreases on the outer peripheral side of the tooth 2 (core). On the other hand, the inner peripheral side of the tooth 2 (core) has a high magnetic flux density. When the tooth 2 (core) is integrally formed, loss due to eddy current increases on the inner peripheral side where the magnetic flux density is high. As shown in FIG. 6 , the eddy current loss is distributed on the inner peripheral side (lower side of the drawing) of the teeth 2 where the coil 5 is accommodated, and a high loss area occurs particularly on the center side of the coil 5 .

Therefore, in this embodiment, the teeth 2 (core) are provided with slits 7 in order to divide the eddy current path. The slits 7 are arranged so that the distance Rs from the center O to the outermost peripheral position of the slit 7 is larger than the distance Rc from the center O to the inner peripheral surface of the recess into which the coil 5 of the tooth 2 is inserted. there is The slit 7 becomes a high resistance portion that increases the resistance value of the eddy current path flowing through the tooth 2 (core), which is a magnetic material, so that the magnetic material can be divided in the area where the loss due to the eddy current is high, thereby suppressing the loss. You can increase the effect.

FIG. 7 is a diagram comparing the ratio of eddy current loss with and without the slit 7 using magnetic field analysis. In FIG. 7, the vertical axis indicates the loss ratio, and the horizontal axis indicates the Z-direction position (Z1 to Z3) of the armature 8. In FIG. The loss ratio varies depending on the Z-direction position of the armature 8, but by inserting the slits 7 in the teeth 2 (core), the loss can be suppressed, and in this example, the average loss can be suppressed by about 30%. ing.

According to this embodiment, the teeth 2 (cores) are provided with slits 7, and the slits 7 are arranged so that the center Since the distance Rs from O to the outermost peripheral position of the slit 7 is made large, the effect of suppressing loss due to eddy current can be enhanced.

A second embodiment of the present invention will be described. FIG. 8 is a schematic diagram showing an example of a linear motor according to Example 2 of the present invention. The schematic diagram of FIG. 8 is a diagram of the linear motor 1 cut along the YZ plane. FIG. 9 is an external perspective view of an armature according to Example 2 of the present invention. FIG. 10 is a rear view of the linear motor according to the second embodiment of the invention as seen from the Z direction. The same reference numerals are assigned to the same configurations as those of the first embodiment, and detailed description thereof will be omitted.

The linear motor 1 of Example 2 has six slits 7a (first slits) arranged to extend from the inner peripheral side to the outer peripheral side of the armature (teeth 2), and arranged to extend from the outer peripheral side to the inner peripheral side. Six slits 7b (second slits) are provided. In the magnetic material on the inner peripheral side of the armature 8 , the magnetic flux concentrates from the outer peripheral portion toward the inner peripheral portion of the circumference of the teeth 2 . That is, the magnetic flux density is sparse in the outer peripheral portion and dense in the inner peripheral portion. It is effective to provide a slit in the inner peripheral portion where the magnetic flux is dense, but the magnetic flux is dense in the inner peripheral portion and saturation of the magnetic flux is likely to occur. If many slits are provided in this area, the magnetic material itself on the inner peripheral side is reduced, and the saturation of the magnetic flux is further enhanced.

Therefore, in Example 2, the slits 7a (first slits) are arranged to extend from the inner peripheral side to the outer peripheral side of the armature magnetic body (teeth 2), and the slits 7a (first slits) are arranged to extend from the outer peripheral side to the inner peripheral side. By efficiently arranging the slits 7b (second slits), the loss suppression effect is enhanced. Although the pattern for arranging the slits is not limited to that shown in FIG. 10, the slits 7a arranged to extend from the inner peripheral side to the outer peripheral side and the slits 7b arranged to extend from the outer peripheral side to the inner peripheral side ( The loss can be effectively suppressed by providing the second slits evenly and alternately.

Here, as shown in FIG. 10, Li is the depth of the slit 7a (first slit) arranged so as to extend from the central axis side of the core on the inner peripheral side toward the outer peripheral side (coil and permanent magnet side). , Lo is the depth of the slit 7b (second slit) arranged to extend from the outer peripheral side to the inner peripheral side of the tooth, and Lt is the radial length (radial thickness) from the inner peripheral side to the outer peripheral side. Then, by setting the relationship Lt≦Li+Lo, the circumferential surface of the magnetic body having the same radius with respect to the central axis is always divided by the slit. In other words, the slit 7a (first slit) and the slit 7b (second slit) are arranged so as to partially overlap in the circumferential direction.

FIG. 11 is a front view of a linear motor according to a comparative example viewed from the Z direction. In FIG. 11, six slits 7a (first slits) arranged to extend from the inner circumference side to the outer circumference side of the teeth 2 of the linear motor 1, and six slits arranged to extend from the outer circumference side to the inner circumference side. 7b (second slit) is included. In the comparative example, the sum of the lengths of the inner and outer circumferences of the slits is shorter than the radial thickness Lt of the tooth, that is, Lt>Li+Lo. In other words, the slit 7a (first slit) and the slit 7b (second slit) are arranged so as not to overlap in the circumferential direction. Normally, the magnetic flux flows in from the outer peripheral side of the teeth 2 so as to be orthogonal to the surfaces. Therefore, if Lt>Li+Lo with respect to this magnetic flux, the surface that receives the inflowing magnetic flux is connected to one on the circumference, for example, in the range shown by D to D' in FIG. There is a side to it. That is, the range indicated by D to D' forms an eddy current path. As a result, the loss in the plane of D to D' increases, and the loss suppressing effect of the slit decreases. That is, when slits are formed from the inside and outside of the teeth 2, it is effective to set the relationship between the lengths Li and Lo of the slits and the thickness Lt of the teeth in the radial direction to Lt≦Li+Lo.

According to the second embodiment, in addition to the effects of the first embodiment, the loss suppressing effect of the slits can be further enhanced.

A third embodiment of the present invention will be described. FIG. 12 is a schematic diagram showing an example of a linear motor according to Example 3 of the present invention. The schematic diagram of FIG. 12 is a diagram of the linear motor 1 cut along the YZ plane. FIG. 13 is an external perspective view of an armature according to Example 3 of the present invention. FIG. 14 is a rear view of the linear motor according to the third embodiment of the present invention as seen from the Z direction. The same reference numerals are assigned to the same configurations as those of the first and second embodiments, and detailed description thereof will be omitted.

The linear motor 1 of Example 3 is provided with 6 slits 7a (first slits) from the inner peripheral side of the magnetic body (teeth 2) of the armature and 12 slits 7b (second slits) from the outer peripheral side. there is At this time, the number of slits 7a (first slits) arranged so as to extend from the central axis side of the teeth 2 (core) on the inner peripheral side toward the outer peripheral side (coil and permanent magnet side) is Si, and the teeth 2 ( When So is the number of slits 7b (second slits) arranged to extend from the outer peripheral side to the inner peripheral side of the core), there is a relationship of So≧Si. Magnetic flux is sparse in the magnetic material of the armature, that is, in the outer periphery of the teeth 2 . As the number of slits increases, the cross-sectional area of the magnetic path decreases and the magnetic flux becomes denser, making it easier for magnetic flux saturation to occur. That is, it is possible to increase the number of slits in that area of the magnetic flux, and it is effective to increase the number of slits So on the outer peripheral side where the magnetic flux is sparse than the number of slits Si on the inner peripheral side. Further, the width of the slit is narrowed to obtain the loss effect of the eddy current, and widened to obtain the cooling effect, so that the intended effect can be obtained more efficiently. Also, by increasing the number of slits, the surface area is increased and the cooling performance is greatly improved.

According to the third embodiment, the surface area of the armature is increased by inserting many slits in consideration of the width of the slits according to the density of the magnetic fluxes on the outer peripheral side and the inner peripheral side of the armature. is possible, the cooling effect is improved, and the loss control effect can also be obtained.

A fourth embodiment of the present invention will be described. FIG. 15 is a schematic diagram showing an example of a linear motor according to Example 4 of the present invention. The schematic diagram of FIG. 15 is a diagram of the linear motor 1 cut along the YZ plane. FIG. 16 is an external perspective view of an armature according to Example 4 of the present invention. FIG. 17 is a rear view of the linear motor according to the fourth embodiment of the present invention as seen from the Z direction. The same reference numerals are given to the same configurations as those of the first to third embodiments, and detailed description thereof will be omitted.

The linear motor 1 of Example 4 has six slits 7a (first slits) arranged so as to extend from the inner peripheral side of the magnetic body (teeth 2) of the armature 8 toward the outer peripheral side, Six slits 7b (second slits) are provided so as to extend sideways. Six slits 7a (first slits) extending from the inner peripheral side of the magnetic bodies (teeth 2) of the armature 8 are provided in parallel in the depth direction (outside in the radial direction). On the other hand, six slits 7b (second slits) extending from the outer peripheral side of the magnetic bodies (teeth 2) of the armature 8 are tapered in the depth direction (radially inward). That is, the width of the slit 7b (second slit) increases toward the outer periphery.

This is because the magnetic flux flowing through the teeth 2 of the armature 8 becomes sparse on the outer peripheral side, so the magnetic flux density decreases toward the outer peripheral side. Therefore, the slit opening can be enlarged by providing the slit 7b (second slit) whose width becomes wider toward the outer peripheral side from the outer peripheral side of the magnetic body (teeth 2).

According to the fourth embodiment, while the cooling effect is enhanced, the influence of the magnetic path cross-sectional area reduction due to the provision of the slits can be reduced, enabling efficient cooling.

An application example of this embodiment is shown in FIGS. 18 and 19. FIG. FIG. 18 is an external perspective view of an armature according to an application example of Example 4 of the present invention. FIG. 19 is a rear view of a linear motor according to an application example of Embodiment 4 of the present invention, viewed from the Z direction.

The linear motor 1 of the application example has six slits 7a (first slits) on the inner peripheral side of the magnetic bodies (teeth 2) of the armature 8, and slits 7b (first slits) that widen from the inner peripheral side to the outer peripheral side. 2 slits) are provided. In the application example, the high thermal conductivity member 9 is inserted into each of the slit 7a (first slit) and the slit 7b (second slit). The magnetic material of the armature 8 is generally made of iron. As the high thermal conductivity member 9, a member having higher thermal conductivity than iron, such as copper, is used. Also, a magnetic material other than the same may be used.

According to the application example, the heat transfer in the axial direction (Z direction) is improved, and the heat generated by the coil 5 can be efficiently dispersed. Furthermore, since the loss suppression effect of the slit can be expected, the loss is small and local heat rise can be suppressed.

A fifth embodiment of the present invention will be described. FIG. 20 is a schematic diagram showing an example of a linear motor according to Example 5 of the present invention. The schematic diagram of FIG. 20 is a diagram of the linear motor 1 cut along the YZ plane. FIG. 21 is an external perspective view of an armature according to Example 5 of the present invention. FIG. 22 is a schematic side view of the linear motor 1 according to Example 5 of the present invention cut along the YZ plane. The same reference numerals are assigned to the same configurations as those of the first to fourth embodiments, and detailed description thereof will be omitted.

The linear motor 1 of Example 5 has six slits 7a (first slits) arranged so as to extend from the inner peripheral side to the outer peripheral side of the magnetic body (teeth 2) of the armature 8, and the magnetic body of the armature 8 Two slits 7c (third slits) are provided on the outer peripheral surface side, that is, on the outer peripheral surface side of the teeth 2 so as to extend along the circumferential direction of the teeth 2 . The slits 7a and 7c are provided for each tooth 2 arranged in the axial direction (Z direction). By providing the slit 7c (third slit) in the circumferential direction at the tip of the tooth 2 on the outer peripheral side, the loss at the outer peripheral portion of the tooth 2 can also be suppressed. Furthermore, by providing the slits 7c (third slits) at the tips of the teeth, higher-order components are included in the components of the magnetic flux density distribution in the axial direction of the gap, and a pulsation reduction effect can be expected.

Here, in Example 5, the depth of the slit 7c (third slit) and the slit The total depth of 7a (first slit) is set larger than the distance between the inner and outer peripheries of armature 8 (teeth 2) (thickness of ring-shaped armature 8). In this case, the slit 7c (third slit) in the circumferential direction and the slit 7a (first slit) extending from the inner peripheral side communicate with each other inside the armature (teeth 2).

Therefore, according to the fifth embodiment, for example, the cooling medium flows in from the axial direction (slits provided from the inner diameter side), flows out from the teeth (circumferential slits) to the gap surface, and flows on the side opposite to the inflow side (in the Z direction). The cooling effect can be enhanced by flowing out from the opposite side). Furthermore, the inside of the armature 8 can be cooled as a whole, and the temperature distribution can be suppressed.

23 and 24 show an application example of the fifth embodiment. FIG. 23 is a schematic diagram showing an example of a linear motor according to an application example of Example 5 of the present invention. FIG. 24 is an external perspective view of an armature according to an application example of Example 5 of the present invention.

In the application example, a slit 7c (third slit) provided in the circumferential direction from the outer peripheral side of the tooth 2 and a slit 7b (second slit) provided in the inner peripheral side from the outer peripheral side of the tooth 2 and penetrating in the axial direction (Z direction). slits) and slits 7a (first slits) provided from the inner peripheral side to the outer peripheral side of the teeth 2 and penetrating in the axial direction (Z direction), and the respective slits are communicated within the armature 8 (teeth 2). ing.

According to the application example, by connecting the slits 7a, 7b, and 7c in the armature 8, the inside of the armature 8 can be uniformly cooled, and the occurrence of loss can be made uniform, and local temperature rise can be suppressed. Although it is preferable to make each slit uniformly, it is also possible to change the position of the slits made in the circumferential direction in the axial direction in consideration of suppression of harmonics.

A sixth embodiment of the present invention will be described. FIG. 25 is a schematic diagram showing an example of a linear motor according to Example 6 of the present invention. FIG. 26 is an external perspective view of an armature according to Example 6 of the present invention. FIG. 27 is a rear view of the linear motor according to the sixth embodiment of the present invention as seen from the Z direction. The same reference numerals are assigned to the same configurations as those of the first to fifth embodiments, and detailed description thereof will be omitted.

The armature 8 has a plurality of convex teeth 2 arranged in the moving direction ((axial direction (Z direction)), and a through hole 3 is provided in the central portion of the teeth 2. The teeth 2 are divided in the circumferential direction. It is divided into 6 by 7d, and the adjacent portions are in contact.Even in this case, since contact resistance (a portion with high electrical resistance) occurs between the contact surfaces, a loss suppression effect can be expected. , The divided portion 7d serves as a high resistance portion that increases the resistance value of the eddy current path flowing through the tooth 2 (core), so that the loss due to the eddy current can be reduced.In other words, the high resistance portion divides the tooth 2 into a plurality of parts. are formed.

Also, as shown in FIG. 26, only the protruding portions (A and B in the drawing) of the convex teeth 2 may be physically divided. According to the sixth embodiment, by doing so, the six parts divided in the circumferential direction can be connected and held. As shown in FIG. 6, since the loss occurs on the outer peripheral side of the coil 5, even if only the surface in contact with the coil 5 is divided, a sufficient effect can be obtained.

An application example of the sixth embodiment will be described with reference to FIGS. 28 to 30. FIG. FIG. 28 is a schematic diagram showing an example of a linear motor according to Application Example 1 of Example 6 of the present invention. FIG. 29 is an external perspective view of an armature according to Application 1 of Embodiment 6 of the present invention. FIG. 30 is a rear view of the linear motor according to application example 1 of embodiment 6 of the present invention as seen from the Z direction.

In the application example 1, the through-holes 3 are not formed in the convex teeth 2 . The teeth 2 are circumferentially divided into six parts by the dividing parts 7d, and the adjacent parts are in contact with each other. Similar effects can be obtained in such a case as well. Also, as in FIG. 26, only the protruding portions (A and B in the drawing) of the convex teeth 2 may be physically divided.

Application Example 2 will be described with reference to FIGS. 31 to 33. FIG. FIG. 31 is a schematic diagram showing an example of a linear motor according to Application Example 2 of Example 6 of the present invention. FIG. 32 is an external perspective view of an armature according to Application 2 of Embodiment 6 of the present invention. FIG. 33 is a rear view of a linear motor according to application example 2 of embodiment 6 of the present invention, viewed from the Z direction.

In Application Example 2, similarly to Application Example 1, through-holes 3 are not formed in convex teeth 2 . In application example 2, slits 7 are formed in convex teeth 2 . The slits may be provided from the inner peripheral side of the teeth 2 and may be provided on the outer peripheral side. By doing so, the magnetic bodies of the armature can be formed integrally and the slits can be provided, so that the armature can be structured with high rigidity.

A seventh embodiment of the present invention will be described. FIG. 34 is a configuration diagram of an electric suspension device equipped with a linear motor according to Embodiment 7 of the present invention. The electric suspension device 100 has an inner rod 90 connected to the inside of an armature composed of teeth 2 and coils 5 , and a rod end 30 and an inner tube 60 are arranged at the ends of the inner rod 90 . For example, the rod end 30 is connected to a suspension link on the tire side. A permanent magnet 10 facing each other with a gap is provided on the outer peripheral side of the armature, and an outer cylinder 20 made of a magnetic material is provided on the outer peripheral side of the permanent magnet 10 . A spring stopper 50 is connected to the outer cylinder 20 and a compressed spring 40 is arranged. The armature connected to the tire side and the secondary side members (permanent magnet 10, outer cylinder 20, etc.) connected to the vehicle body move relatively linearly and are supported by the inner tube sliding member 80. FIG. A rod support member 70 is coupled to the outer cylinder 20, and the rod support member 70 is provided with, for example, a bearing or a slide bearing so that the movable portion can relatively move linearly.

Any one of the above-described first through sixth embodiments may be applied to the linear motor of the seventh embodiment. According to the seventh embodiment, it is possible to provide an electric suspension device having the effects of the first to sixth embodiments.
[Description common to each embodiment]
The present invention reduces eddy current loss due to concentration of magnetic flux generated on the central axis side of the armature. In each of the above-described embodiments, slits provided in the magnetic material are used to divide the eddy current path and lengthen the path of the eddy current path. It is not limited to slits. For example, a method of inserting a high resistance member, a method of dividing a part without a gap such as a slit, etc., and the like can be obtained if a high resistance portion is generated on the teeth (core) due to contact resistance. That is, even if the width of the cut or slit is zero, there may be a high resistance portion such as contact resistance generated when two members come into contact with each other. In this embodiment, the effective depth of the cuts and slits has been described as an example. It doesn't matter if

DESCRIPTION OF SYMBOLS 1... Linear motor 2... Teeth 2a... Protruding part 2b... Flat plate part 3... Through hole 5... Coil 7, 7a, 7b, 7c... Slit 8... Armature 9... High thermal conductivity member 10 Permanent magnet 20 Outer cylinder 30 Rod end 40 Spring 50 Spring stopper 60 Inner tube 70 Rod supporting member 80 Inner tube sliding member 90 Inner rod 100 Electric suspension device

Claims (18)

A linear motor comprising: an armature having teeth and coils provided on the teeth; and a permanent magnet provided on an outer peripheral side of the armature, wherein the armature and the permanent magnets move relative to each other. ,
A linear motor, wherein the teeth are provided with high resistance portions that increase a resistance value of an eddy current path flowing through the teeth. In claim 1,
When the distance from the center of the tooth to the inner peripheral side surface of the recess of the tooth into which the coil is inserted is Rc, and the distance from the center of the tooth to the outermost periphery of the high resistance portion is Rs, Rs>Rc A linear motor characterized by having a relationship of In claim 2,
A linear motor, wherein each of the teeth has a through hole at its center. In claim 3,
A linear motor, wherein a plurality of said teeth are provided in the moving direction. In claim 1,
A linear motor, wherein the high resistance portion is a slit. In claim 5,
The linear motor, wherein the slit is a first slit arranged to extend from the inner peripheral side to the outer peripheral side of the tooth. In claim 6,
A linear motor, comprising: a second slit arranged to extend from an outer peripheral side to an inner peripheral side of the teeth. In claim 7,
A plurality of the first slits and the second slits are provided,
A linear motor, wherein the second slit is positioned between the adjacent first slits. In claim 7 or 8,
When Li is the depth of the first slit, Lo is the depth of the second slit, and Lt is the radial length from the inner peripheral side to the outer peripheral side of the tooth, there is a relationship of Lt≦Li+Lo. A linear motor characterized by: In claim 7 or 8,
A linear motor, wherein the number of said first slits is Si and the number of said second slits is So, wherein a relationship of So≧Si is satisfied. In claim 7 or 8,
The linear motor, wherein the width of the second slit increases from the inner peripheral side to the outer peripheral side. In claim 11,
A linear motor, wherein a member having a higher thermal conductivity than iron is inserted into the first slit and the second slit. In claim 6,
A linear motor, comprising a third slit extending in a circumferential direction on an outer peripheral surface of the tooth. In claim 13,
A linear motor, wherein the sum of the depth of the first slit and the depth of the third slit is larger than the distance between the inner circumference and the outer circumference of the tooth. In claim 14,
A linear motor, wherein the first slit and the third slit communicate with each other inside the teeth. In claim 7,
A third slit arranged to extend in the circumferential direction is provided on the outer peripheral surface of the tooth,
A linear motor, wherein the first slit, the second slit, and the third slit communicate with each other inside the teeth. In claim 1,
A linear motor, wherein the high resistance portion is formed by dividing the tooth into a plurality of pieces. An electric suspension device comprising the linear motor according to any one of claims 1 to 17.

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