Cylindrical linear motor

Abstract

To provide a cylindrical type liner motor capable of reducing a cogging thrust even if there is a dimension error in a core.SOLUTION: A cylindrical type liner motor 1 comprises: a field magnet F; an armature 2 having a plurality of cores 31, 32 that has a cylinder shape, is movably arranged to an axial direction to the field magnet F, has a plurality of teeth 3b, and is arranged with an interval to the axial direction, and a winding 4 mounted to a slot 3c between the teeth 3b and 3b of each core; and a plurality of holders 21 and 22 that holds the core 31, 32 one by one. Each of the holders 21 and 22 includes: core mounting parts 21a and 22a having a length of the axial direction than that of the core 31, 32; opposite parts 21b and 22b that are provided to one end side of the core mounting parts 21a and 22a; and connection parts 21c and 22d that connect both of the holders 21 and 22. In all of the cores 21 and 22, an axial direction length L3 and an axial direction length L4 of the core mounting parts 21a and 22a are equivalent, and an axial direction length LF1 and an axial direction length LF2 of opposite parts 21b and 22b are equivalent.SELECTED DRAWING: Figure 1

Description

Technical Field

[0001] The present invention relates to a tubular linear motor.

Background Art

[0002] A tubular linear motor includes, for example, a cylindrical field magnet and an armature axially movably inserted into the field magnet. The armature includes a plurality of cores that are annular and have a plurality of annular teeth on the outer periphery, and windings mounted in slots between the teeth. In the tubular linear motor configured in this way, the field magnet can be driven axially with respect to the armature by energizing the windings of the armature.

[0003] In a tubular linear motor, since the driving direction of the field magnet is axial, the cores in the armature have ends in the axial direction, and cogging thrust due to the end effect of the cores is generated.

[0004] In order to reduce such cogging thrust due to the end effect of the cores, a tubular linear motor has been proposed in which the armature is configured by providing a gap of a length equal to half of the pole pitch between the cores in the axial direction. In the tubular linear motor configured in this way, the cogging thrust due to the end effect of one core is canceled out by the cogging thrust due to the end effect of the other core, thereby reducing the cogging thrust as a whole (see, for example, Patent Document 1).

Prior Art Documents

Patent Documents

[0005]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0006] In the cylindrical linear motor disclosed in Patent Document 1, although the cores are arranged axially with the distance between the cores being set to a length equal to half of the pole pitch so that the cogging thrust of one core cancels out the cogging thrust of the other core, if there are dimensional errors in the cores, the dimensional errors of the cores accumulate in the entire armature and each core is not arranged at an appropriate position, resulting in a problem that the effect of reducing the cogging thrust is diminished.

[0007] Therefore, an object of the present invention is to provide a cylindrical linear motor capable of reducing the cogging thrust even when there are dimensional errors in the cores.

Means for Solving the Problems

[0008] To achieve the above object, the cylindrical linear motor of the present invention includes a field magnet, and an armature including a plurality of cores that are cylindrical and arranged so as to be movable axially with respect to the field magnet and provided side by side axially around the field magnet side, and a winding mounted in a slot between the teeth of the cores, and a plurality of holders that hold the cores one by one and are provided in the same number as the cores and connected to each other axially. Each holder has a core mounting portion on which the core is mounted and which is longer in the axial direction than the core, an opposing portion provided on one end side of the core mounting portion and opposing one end side of the core, and a connecting portion that connects the holders to each other. In all the holders, the axial lengths of the core mounting portions are equal, and the axial lengths of the opposing portions are equal.

[0009] According to the cylindrical linear motor configured as described above, since the core is mounted on the core mounting portion of the corresponding holder, which is longer in the axial direction than the axial length of the core in the holder, and the holders are connected to each other axially, the cores are positioned axially by the holders without being affected by each other's dimensions. Even if there are dimensional errors in the axial lengths of the cores, the cores can be positioned at appropriate positions by correctly managing only the dimensions of the holders.

[0010] Further, taking the position of one end in the axial direction of the armature as the reference position, setting the reference length obtained by adding the designed axial length of the core and the predetermined length as L, and setting the order of the cores counted from one end side in the axial direction of the armature as N (where N is an integer of 2 or more), the Nth core in the axial direction of the armature may be arranged at a distance of (N - 1)×L from the reference position.

[0011] According to the tubular linear motor configured in this way, one end of the second and subsequent cores installed in the armature is always arranged at a distance of (N - 1)×L from the reference position based on one end of the anti-core side end of the first core. Since the dimensional errors of all the cores do not overlap in the axial direction of the armature, the displacement of the arrangement of each core with respect to the field magnet can be accommodated within the dimensional error of each core.

[0012] Furthermore, the total axial length of the core mounting portion and the opposing portion of the holder in the tubular linear motor may be equal to the reference length obtained by adding the designed axial length of the core and the predetermined length. According to the tubular linear motor configured in this way, after mounting the cores corresponding to each holder, by simply connecting the holders, one end of the second and subsequent cores installed in the armature can always be arranged at a distance of (N - 1)×L from the reference position based on one end of the anti-core side end of the first core.

[0013] Also, the predetermined length may be set to a length that is an integer multiple of the slot pitch. According to the tubular linear motor configured in this way, there is no reduction in thrust, and the windings of each core can be driven by a single drive circuit.

[0014] Furthermore, in the tubular linear motor, one opposing portion of adjacent holders and the other core mounting portion of adjacent holders may be in contact.

[0015] According to the tubular linear motor configured in this way, by simply connecting the holders, the cores can be automatically positioned at appropriate positions.

[0016] In addition, the tubular linear motor may have a screw shaft provided at either the core mounting portion or the opposing portion of the connecting portion, and a screw hole provided at the other of the core mounting portion and the opposing portion and into which the screw shaft is screwed. According to the tubular linear motor configured in this way, after mounting the core on the core mounting portion of the corresponding holder, the tubular linear motor can be easily manufactured simply by screwing the screw shaft into the screw hole to connect the holders.

Effects of the Invention

[0017] According to the tubular linear motor of the present invention, cogging thrust can be reduced even if there is a dimensional error in the core.

Brief Description of the Drawings

[0018]

Figure 1

Figure 2

Modes for Carrying Out the Invention

[0019] Hereinafter, the present invention will be described based on the embodiments shown in the drawings. As shown in FIG. 1, a tubular linear motor 1 in one embodiment includes a field magnet F, and a plurality of teeth 3b that are cylindrical and arranged axially around the field magnet F and are arranged at intervals in the axial direction. The armature 2 includes two cores 31 and 32 arranged at intervals, and windings 4 mounted in slots 3c between the teeth 3b and 3b of the cores 31 and 32. The tubular linear motor 1 further includes two holders 21 and 22 that hold the cores 31 and 32 one by one and are provided in the same number as the cores 31 and 32 and are axially connected to each other. The subscript numbers of the cores 31 and 32 indicate the order when counted from one end 2a side, which is the right end side in FIG. 1 in the axial direction of the armature 2. The core 31 indicates the first core counted from one end 2a side of the armature 2, and the core 32 indicates the second core counted from one end 2a side of the armature 2.

[0020] Hereinafter, each part of the tubular linear motor 1 will be described in detail. The armature 2 includes cores 31 and 32 and windings 4 mounted in slots 3c between teeth 3b of the cores 31 and 32, and is mounted on the outer periphery of the non-magnetic rod 11. In the tubular linear motor 1 of the present embodiment, the magnetic field F is in a tubular shape, and the armature 2 is inserted into the magnetic field F so as to be axially movable and can relatively move axially with respect to the magnetic field F. In the present embodiment, it is used as a stator.

[0021] The cores 31 and 32 are both of the same shape and are configured to include a cylindrical core body 3a and a plurality of teeth 3b provided on the outer periphery of the core body 3a in an annular shape, and are mounted side by side in the axial direction with a space on the outer periphery of the rod 11.

[0022] As described above, the core body 3a is cylindrical, and its cross-sectional area is such that the wall thickness is ensured to be equal to or greater than the area of the cross-section formed when the teeth 3b are cut by the cylinder, no matter where the cylinder centered on the axis of the core 3 cuts from the inner periphery to the outer periphery of the teeth 3b.

[0023] In the present embodiment, as shown in FIG. 1, ten teeth 3b are provided on the outer periphery of the core 3 side by side at equal intervals in the axial direction, and slots 3c are formed, which are gaps where windings 4 are respectively mounted between the teeth 3b. In the present embodiment, the teeth 3b have a trapezoidal cross-sectional shape and the width at the inner periphery is larger than the width at the outer periphery to ensure a larger magnetic path cross-sectional area on the inner periphery side. However, the teeth 3b may have a rectangular cross-sectional shape with the same axial length (width) from the inner periphery to the outer periphery.

[0024] Also, in the present embodiment, a total of nine slots 3c, which are gaps, are provided between adjacent teeth 3b, 3b in FIG. 1. And a winding 4 is wound around and attached to these slots 3c. The winding 4 is a three-phase winding of U-phase, V-phase, and W-phase. Also, in the nine slots 3c of the core 31 on the right side in FIG. 1, the windings 4 of W-phase, W-phase, W-phase and U-phase, U-phase, U-phase, U-phase and V-phase, V-phase, V-phase, V-phase and W-phase are attached in order from the left side in FIG. 1. In the nine slots 3c of the core 32 on the left side in FIG. 1, the windings 4 of W-phase and U-phase, U-phase, U-phase, U-phase and V-phase, V-phase, V-phase, V-phase and W-phase, W-phase, W-phase are attached from the left side in FIG. 1. Also, although not specifically shown, the cores 31 and 32 are manufactured by axially laminating and bonding ten pieces axially divided so as to include one tooth 3b each.

[0025] And the cores 31 and 32 configured in this way are attached to the outer periphery of a rod 11 formed of a non-magnetic material, which is an output shaft. The rod 11 includes holders 21 and 22 that hold one core 31 and 32 each and are provided in the same number as the cores 31 and 32 and are axially connected in the axial direction of the tubular linear motor 1, and a connecting rod 23 connected to the holder 22 on the left side in FIG. 1.

[0026] The first holder 21 counted from the right end side in FIG. 1, which is on the one end 2a side in the axial direction of the armature 2, is formed of a non-magnetic material, and includes a core mounting portion 21a on the outer periphery of which the core 3 is mounted, a disk-shaped opposing portion 21b provided at one end side on the right end side in FIG. 1 of the core mounting portion 21a and opposing to one end on the anti-core side, which is the right end side of the core 31, and a screw hole 21c opening from the other end side, which is the left end side of the core mounting shaft 21a.

[0027] The core mounting portion 21a is cylindrical and has an outer diameter set to a diameter that can be fitted into the inner circumference of the core 31, and has a screw portion 21a1 on the outer circumference of the other end that becomes the left end. Further, a screw hole 21c opens from the other end that becomes the left end of the core mounting shaft 21a. The opposing portion 21b is integrally provided at one end of the core mounting portion 21a. The opposing portion 21b is disk-shaped and has a wear ring 21b1 on its outer circumference that slidably contacts the inner circumference of the inner tube 9 in the field magnet F described later. Further, the length L3 of the core mounting portion 21a is set to the length obtained by subtracting the axial length LF1 of the opposing portion 21b from the reference length L, and is longer than the axial length of the core 31 mounted on the core mounting portion 21a.

[0028] The reference length L is the length obtained by adding the design length L1, which is the design axial length of the cores 31 and 32, and a predetermined length L2, which is twice the slot pitch P in the core 3. In other words, in the axial direction of the holder 21, the distance L5 from the end on the side opposite to the opposing portion of the core mounting portion 21a to the end on the side opposite to the core mounting of the opposing portion 21b is equal to the reference length L. In the cylindrical linear motor 1 of the present embodiment, since the phase of the winding 4 mounted in the slot 3c of each core 3 is set as described above, the predetermined length L2 is set to twice the slot pitch P, but it is also possible to set the predetermined length L2 to an integer multiple of the slot pitch P depending on the arrangement of the phases of the windings 4.

[0029] And the first core 31 counted from the right end side in FIG. 1, which is the one end side of the armature 2 in FIG. 1, is held by the holder 21. Specifically, after inserting the core mounting portion 21a of the holder 21 into the core 31, a nut 24 formed of a non-magnetic material is screwed onto the screw portion 21a1 of the core mounting portion 21a. Then, the core 31 is sandwiched between the opposing portion 21b and the nut 24 and fixed to the outer circumference of the core mounting portion 21a and held by the holder 21. Note that an adhesive may be applied to the screw portion 21a1 to prevent the nut 24 from loosening, or another nut for tightening the nut 24 may be screwed onto the screw portion 21a1 in addition to the nut 24 to prevent the nut 24 from loosening, or another structure may be used to prevent the nut 24 from loosening.

[0030] The second holder 22, counting from the right end in FIG. 1, which is on one end side of the armature 2, is formed of a non-magnetic material, and has a core mounting portion 22a on the outer periphery of which the second core 32, counting from one end side of the armature 2, is mounted, an opposing portion 22b provided on one end side, which is the right end side in FIG. 1, of the core mounting portion 22a and opposing the one end side, which is the right end side, of the core 32, a screw hole 22c opening from the other end side, which is the left end side, of the core mounting portion 22a, and a screw shaft 22d protruding from one end side, which is the right end side, of the opposing portion 22b and screwed into the screw hole 21c of the adjacent holder 21.

[0031] The core mounting portion 22a is cylindrical and has an outer diameter set to a diameter that can be fitted into the inner periphery of the core 32, and has a screw portion 22a1 on the outer periphery of the other end, which is the left end. Also, the screw hole 22c opens from the other end, which is the left end, of the core mounting portion 22a. The opposing portion 22b is integrally provided at one end of the core mounting portion 22a. The opposing portion 22b has a wear ring 22b1 that slidably contacts the inner periphery of an inner tube 9, which will be described later, on the outer periphery.

[0032] Then, the second core 32, counting from the right end in FIG. 1, which is on one end side of the armature 2, is held by the holder 22. Specifically, after inserting the core mounting portion 22a of the holder 22 into the core 3, a nut 25 formed of a non-magnetic material is screwed onto the screw portion 22a1 of the core mounting portion 22a. Then, the core 32 is clamped between the opposing portion 22b and the nut 25 and fixed to the outer periphery of the core mounting portion 22a and held by the holder 22. Note that an adhesive may be applied to the screw portion 22a1 to prevent loosening of the nut 25, or another nut for tightening the nut 25 may be screwed onto the screw portion 22a1 in addition to the nut 25 to prevent loosening of the nut 25, or other structures may be used to prevent loosening of the nut 25.

[0033] Note that the axial length LF2 of the opposing portion 22b of the holder 22 is equal to the axial length LF1 of the opposing portion 21b of the holder 21. The length L4 of the core mounting portion 22a of the holder 22 is set to be the length obtained by subtracting the axial length LF2 of the opposing portion 22b from the reference length L, and is longer than the axial length of the core 32 mounted on the core mounting portion 22a. Therefore, the length L4 of the core mounting portion 22a of the holder 22 is equal to the length L3 of the core mounting portion 21a of the holder 21. That is, in all the holders 21 and 22, the axial lengths L3 and L4 of the core mounting portions 21a and 22a are equal, and the axial lengths LF1 and LF2 of the opposing portions 21b and 22b are equal. Therefore, in the axial direction of the holder 22, the distance L6 from the end on the side opposite to the opposing portion of the core mounting portion 22a to the end on the side opposite to the core mounting side of the opposing portion 22b is equal to the reference length L. Also, the holders 21 and 22 differ only in that the holder 22 has the screw shaft 22d while the holder 21 does not have a screw shaft, and their other structures, shapes, and dimensions are the same. In the holders 21 and 22, the right side from the right end in FIG. 1 of the core mounting portions 21a and 22a is entirely the opposing portions 21b and 22b. The shapes of the opposing portions 21b and 22b in the holders 21 and 22 are disk-shaped, but are not limited to disk-shaped as long as they can contact the cores 31 and 32 and position the cores 31 and 32 in the axial direction, and can be arbitrarily redesigned. For example, a shape in which only the portion where the cores 31 and 32 contact has a large diameter and the diameter of the other portions is small can also be adopted. Also, as long as the axial lengths are the same, the shapes of the opposing portions 21b and 22b may be different between the holders 21 and 22.

[0034] Then, the second holder 22 with the second core 32 mounted thereon is screwed into the screw hole 21c of the first holder 21 with the first core 31 mounted thereon, which is arranged to the right in FIG. 1, and is connected to the first holder 21. In the present embodiment, the connecting portion for connecting the holders 21 and 22 is composed of the screw hole 21c in the holder 21 and the screw shaft 22d in the holder 22. In this way, the screw shaft 22d of the holder 22 is screwed into the screw hole 21c of the holder 21 adjacent to the holder 22, and one end of the opposing portion 22b of the holder 22, which is the right end in FIG. 1, is brought into contact with the other end of the core mounting portion 21a of the holder 21, which is the left end in FIG. 1. As described above, the axial length L3 of the core mounting portion 21a is the length obtained by subtracting the axial length LF1 of the opposing portion 21b from the reference length L, and the axial lengths LF1 of the opposing portion 21b and LF2 of the opposing portion 22b are both equal. Also, the total axial lengths L5 and L6 of the core mounting portions 21a and 22a and the opposing portions 21b and 22b, excluding the connecting portion for connecting the holders 21 and 22, that is, the axial length from the left end in FIG. 1 of the core mounting portions 21a and 22a of the holders 21 and 22 to the right end in FIG. 1 of the opposing portions 21b and 22b, is equal to the reference length L obtained by adding the axial design lengths of the cores 31 and 32 and the predetermined length.

[0035] As described above, when the holder 21 and the holder 22 are axially connected to each other and one end of the opposing portion 22b of the holder 22 is brought into contact with the other end of the core mounting portion 21a of the holder 21, the distance from the other end, which is the left end in FIG. 1 of the opposing portion 21b of the holder 21, to the other end, which is the left end in FIG. 1 of the opposing portion 22b of the holder 22, is always the reference length L. Then, when the first holder 21 and the second holder 22 are connected, a gap of a predetermined length L2 is formed between the first core 31 and the second core 32 in the axial direction. As described above, in the tubular linear motor 1 of the present embodiment, the predetermined length L2 is set to 2P, which is twice the slot pitch P of the cores 31 and 32.

[0036] When cores 31 and 32 corresponding to the holders 21 and 22 constituting the rod 11 are attached respectively, each core 3 is held by the holders 21 and 22 being clamped by the opposing portions 21b and 22b and the nuts 24 and 25. Therefore, with one end 2a of the armature 2 as the reference position in the axial direction, the distance from the one end 2a side to the one end that becomes the right end of the core 32 arranged second in FIG. 1 is equal to the reference length L. And when the actual axial lengths of the cores 31 and 32 are equal to the designed length L1, the distance between the first core 31 and the second core 32 is equal to a predetermined length L2 set to a length 2P which is twice the slot pitch P.

[0037] In addition, when three or more cores 3 are provided, the holders 22 may be added to the left end of the holder 22 in FIG. 1 so that the number of holders 22 is the same as the number of cores 3. That is, when the number of cores 3 installed in the armature 2 is N (where N is an integer of 2 or more), the Nth core 3 is held by the Nth holder 22 counted from the one end 2a side in the axial direction of the armature 2. N By holding the cores 3 in this way, the holders 22 holding the cores 3 may be sequentially connected to the holder 21 holding the core 31. When the holders 21 and 22 holding the cores 31, 32, ···, 3 are connected in this way, among the cores 3, with the position of one end 2a of the armature 2 in the axial direction as the reference position, the reference length L is the sum of the designed axial length L1 and the predetermined length L2 of the cores 31 and 32, and when the order of the cores 3 counted from the one end 2a side in the axial direction of the armature 2 is N (where N is an integer of 2 or more), the Nth core 3 in the axial direction of the armature 2 N is arranged at a distance of (N - 1)×L from the reference position. N Next, the connecting rod 23 is provided with a screw shaft 23a at one end that becomes the right end in FIG. 1, and is connected to the holder 22 by screwing the screw shaft 23a into the screw hole 22c of the holder 22. In this way, in the cylindrical linear motor 1 of the present embodiment, the rod 11 is composed of two holders 21 and 22 and the connecting rod 23. N

[0038]

[0039] Further, on the outer periphery of the connecting rod 23, a slider 12 formed of a non-magnetic material and having a wear ring 12a on its outer periphery is mounted. And the rod 11 holding the armature 2 is inserted axially movably into the field magnet F. The left end of the rod 11 in FIG. 1 protrudes outward from the barrel 7 through the inside of an annular head cap 15 mounted on the left end of the barrel 7 in FIG. 1 that covers the outer periphery of the field magnet F. Also, on the base end side which is the left end side of the rod 11 in FIG. 1, a bracket 16 that enables attachment to a device or the like where the tubular linear motor 1 is installed is attached.

[0040] In addition, the windings 4 of the same phase mounted in the slots 3c of each core 3 are connected in series by jumper wires (not shown). Also, the lead wires 17 drawn from the windings 4 at the other ends of the phases connected in series are drawn out from the base end side which is the left end of the rod 11 in FIG. 1 to the outside of the tubular linear motor 1 through the annular gap between the rod 11 and the cylindrical cover 14 covering the outer periphery of the rod 11, and are connected to a power source via a drive circuit such as an inverter (not shown). And in the tubular linear motor 1 of the present embodiment, the armature 2 functions as a stator.

[0041] On the other hand, in the present embodiment, the field magnet F includes a magnet array 6 configured by alternately laminating a plurality of annular main-pole permanent magnets 6a and a plurality of annular sub-pole permanent magnets 6b in the axial direction, and a cylindrical back yoke 8 formed of a magnetic material and fitted on the outer periphery of the magnet array 6.

[0042] The field magnet F is accommodated in an annular gap formed between a barrel 7 formed of a cylindrical non-magnetic material and an inner tube 9 formed of a cylindrical non-magnetic material inserted into the barrel 7. In the present embodiment, the field magnet F functions as a mover. Thus, the mover of the tubular linear motor 1 of the present embodiment is configured to include the field magnet F, the barrel 7, and the inner tube 9.

[0043] Note that the triangular marks shown on the permanent magnet 6a of the main pole and the permanent magnet 6b of the auxiliary pole in Fig. 1 indicate the magnetization directions. The magnetization direction of the permanent magnet 6a of the main pole is in the radial direction, and the magnetization direction of the permanent magnet 6b of the auxiliary pole is in the axial direction. The permanent magnet 6a of the main pole and the permanent magnet 6b of the auxiliary pole are alternately laminated, and are arranged such that the magnetic pole arrangements of adjacent permanent magnets 6a of the main poles and adjacent permanent magnets 6b of the auxiliary poles are opposite to each other, forming a magnet array 6 in a so-called Halbach array. And, on the inner peripheral side of the field magnet F, the permanent magnets 6a and 6b are arranged such that S poles and N poles appear alternately in the axial direction.

[0044] Also, the axial length of the permanent magnet 6a of the main pole is longer than the axial length of the permanent magnet 6b of the auxiliary pole, and in the present embodiment, it is set to be in the range of 2 to 5 times the axial length of the permanent magnet 6b of the auxiliary pole. If the axial length of the permanent magnet 6a of the main pole is set to be in the above-described range, the magnetic resistance between the permanent magnet 6a of the main pole and the cores 31 and 32 can be reduced, and the magnetic field acting on the cores 31 and 32 can be increased, so that the thrust of the tubular linear motor 1 can be improved.

[0045] Also, in the tubular linear motor 1 of the present invention, a back yoke 8 is provided on the outer periphery of the magnet array 6 formed by the permanent magnets 6a and 6b. By providing the back yoke 8, a magnetic path with low magnetic resistance can be secured even if the axial length of the permanent magnet 6b of the auxiliary pole is shortened, so that the thrust of the tubular linear motor 1 when the axial length of the permanent magnet 6a of the main pole is increased can be effectively improved. More specifically, when the back yoke 8 is provided on the outer periphery of the permanent magnets 6a and 6b, a magnetic path with low magnetic resistance can be secured, so that an increase in magnetic resistance is suppressed even if the axial length of the permanent magnet 6b of the auxiliary pole is shortened. Therefore, increasing the axial length of the permanent magnet 6a of the main pole to be longer than the axial length of the permanent magnet 6b of the auxiliary pole and providing a cylindrical back yoke 8 on the outer periphery of the permanent magnets 6a and 6b can greatly improve the thrust of the tubular linear motor 1. The thickness of the back yoke 8 may be set to a thickness suitable for suppressing an increase in the external magnetic resistance of the permanent magnet 6a of the main pole. Note that although providing the back yoke 8 can suppress an increase in magnetic resistance, it is also possible to omit the back yoke 8.

[0046] Note that the permanent magnet 6b of the auxiliary pole is a permanent magnet having a coercive force higher than that of the permanent magnet 6a of the main pole. The residual magnetic flux density and the coercive force in a permanent magnet are closely related to each other. Generally, when the residual magnetic flux density is increased, the coercive force decreases, and when the coercive force is increased, the residual magnetic flux density decreases, which is an inverse relationship. In the Halbach array, since a strong magnetic field is applied to the permanent magnet 6b of the auxiliary pole in the demagnetizing direction, the coercive force of the permanent magnet 6b of the auxiliary pole is increased to suppress demagnetization, and a strong magnetic field is made to act on the cores 31 and 32. On the other hand, the strength of the magnetic field acting on the cores 31 and 32 depends on the number of magnetic force lines of the permanent magnet 6a of the main pole. Therefore, a permanent magnet with a high residual magnetic flux density is used for the permanent magnet 6a of the main pole to make a strong magnetic field act on the cores 31 and 32. In the present embodiment, when making the coercive force of the permanent magnet 6b of the auxiliary pole higher than that of the permanent magnet 6a of the main pole, the material of the permanent magnet 6b of the auxiliary pole is a material having a higher coercive force than the material of the permanent magnet 6a of the main pole. Thus, by selecting the material, the combination of the permanent magnet 6a of the main pole and the permanent magnet 6b of the auxiliary pole can be easily realized. Note that in the present embodiment, the permanent magnet 6a of the main pole is composed of a material having a high residual magnetic flux density mainly composed of neodymium, iron, and boron, and the permanent magnet 6b of the auxiliary pole is composed of a magnet that is difficult to demagnetize by increasing the addition amount of heavy rare earth elements such as dysprosium and terbium to the above material.

[0047] As described above, the field winding F has a configuration in which the permanent magnets 6a and 6b are laminated in a Halbach array so as to apply a stronger magnetic field to the armature 2. However, as long as the permanent magnets can be laminated in an array other than the Halbach array so that the S pole and the N pole appear alternately in the axial direction on the armature 2 side to apply a magnetic field to the armature 2, it may be composed of a plurality of laminated permanent magnets.

[0048] Next, the inner tube 9 is cylindrical and made of a non-magnetic material, and is fitted to the inner circumference of the field magnet F. Further, at the left end of the inner tube 9 in FIG. 1, a head cap 15 having an annular inner diameter smaller than the inner diameter of the inner tube 9 and an outer diameter larger than the outer diameter of the inner tube 9 is integrally provided. Also, on the inner circumference of the inner tube 9, wear rings 12a, 21b1, 22b1 provided at the opposing portions 21b, 22b of the slider 12 attached to the rod 11 and the holders 21, 22 of the rod 11 are in sliding contact, and the armature 2 supported at three points by the slider 12 and the opposing portions 21b, 22b of the holders 21, 22 can move smoothly in the axial direction without being eccentric with respect to the field magnet F together with the rod 11. The inner tube 9 forms an annular gap between the outer circumferences of the cores 31, 32 and the inner circumference of the field magnet F, and serves to guide the axial movement of the armature 2 in cooperation with the slider 12 and the opposing portions 21b, 22b of the holders 21, 22. Note that the inner tube 9 may be made of a non-magnetic material, but if it is made of a synthetic resin, the effect of improving the mass thrust density of the tubular linear motor 1 becomes higher. The mass thrust density is an index indicating the performance of the tubular linear motor 1, and the higher the numerical value, the more efficiently the thrust can be exerted. Also, when the armature 2 is inserted into the field magnet F, the inner tube 9 prevents the core 3 from being adsorbed to the field magnet F, so that good assemblability can be realized. Thus, there are many advantages to providing the inner tube 9, but it is also possible to omit the inner tube 9.

[0049] Further, the inner tube 9 may be made of a non-magnetic metal. However, when it is made of a non-magnetic metal, eddy currents are generated inside the inner tube 9 when the rotor 2 moves in the axial direction, and a force is generated to prevent the movement of the rotor 2. On the other hand, if the inner tube 9 is made of a synthetic resin, no eddy current is generated, so that the thrust of the tubular linear motor 1 can be more effectively improved and the mass of the tubular linear motor 1 can be reduced. When the inner tube 9 is made of a synthetic resin, if it is manufactured from a fluororesin, friction and wear between the slider 12 and the opposing portions 21b, 22b of the holders 21, 22 can be reduced. Further, the inner tube 9 may be formed of another synthetic resin, or the inner circumference of the inner tube 9 formed of another synthetic resin may be coated with a fluororesin to reduce friction and wear.

[0050] The barrel 7 is formed in a bottomed cylindrical shape of a non-magnetic material, and adhesion of contaminants such as black sand to the outer periphery of the barrel 7 is prevented by the magnetic force of the field magnet F. The right end of the barrel 7 and the inner tube 9 in FIG. 1 is closed by the bottom 7a of the barrel 7, and the left end of the barrel 7 in FIG. 1 is closed by a head cap 15 provided at the left end of the inner tube 9 and screwed to the inner circumference of the barrel 7. Further, the bottom 7a at the right end of the barrel 7 in FIG. 1 is provided with a bracket 7b by which the tubular linear motor 1 can be attached to equipment or the like. The tubular linear motor 1 is attached and used for equipment or the like by using a bracket 16 attached to the base end of the rod 11 on the stator side and a bracket 7b provided at the bottom 7a that closes the end of the barrel 7 on the mover side.

[0051] In this embodiment, the inner tube 9 and the head cap 15 are integrated and configured as a single component. However, the inner tube 9 and the head cap 15 may be configured as separate components. Further, when fixing the barrel 7 and the head cap 15, other fixing methods such as fastening with bolts and nuts or welding may be adopted in addition to screw fastening. Further, the cylindrical portion and the bottom 7a of the barrel 7 may be separate components and connected to each other.

[0052] The head cap 15 is provided with a sealing member 15a for sealing around the axis of the cover 14 that covers the rod 11 inserted into the inner periphery, preventing the intrusion of dust, water, etc. into the cylindrical linear motor 1. Further, the axial lengths of the barrel 7 and the inner tube 9 are longer than the total axial length of the stator 2, the slider 12, and the opposing portions 21b, 22b of the respective holders 21, 22, and the stator 2 can stroke left and right in FIG. 1 within the range of the axial length in the magnetic field F.

[0053] Note that the magnet row 6 formed by laminating the permanent magnets 6a, 6b in the magnetic field F is sandwiched between the bottom 7a that closes the end of the barrel 7 and the head cap 15 screwed to the open end of the barrel 7 and fixed to the barrel 7. Specifically, annular retainers 18, 19 are interposed between the left end of the magnet row 6 in FIG. 1 and the head cap 15, and between the right end of the magnet row 6 in FIG. 1 and the bottom 7a, respectively. Through these retainers 18, 19, the magnet row 6 is sandwiched between the head cap 15 and the bottom 7a and fixed to the barrel 7 of the magnetic field F, and the axial position with respect to the barrel 7 is adjusted. Note that if the position adjustment and fixation of the magnetic field F can be performed with the head cap 15 and the bottom 7a of the barrel 7, the retainers 18, 19 can be omitted. Further, the retainers 18, 19 may each be configured by laminating a plurality of washers.

[0054] The tubular linear motor 1 can have the armature 2 and the field F move relative to each other in the axial direction, and by energizing the winding 4, the field F, which is the mover, can be driven in the axial direction to apply a thrust to the device or the like. Then, for example, by sensing the electrical angle of the field F with respect to the winding 4, performing conduction phase switching based on the electrical angle, and controlling the current amount of each winding 4 by PWM control, the thrust in the tubular linear motor 1 and the moving direction of the field F, which is the mover, can be controlled. Note that the above control method is an example and is not limited thereto. Thus, in the tubular linear motor 1 of the present embodiment, the armature 2 is the stator, and the field F acts as the mover. Also, when an external force that causes relative displacement between the armature 2 and the field F in the axial direction acts, a thrust that suppresses the relative displacement is generated by energizing the winding 4 or the induced electromotive force generated in the winding 4, and the vibration and movement of the device due to the external force can be damped in the tubular linear motor 1, and energy regeneration that generates electric power from the external force is also possible.

[0055] As described above, the tubular linear motor 1 of the present embodiment includes an armature 2 having a cylindrical field F, a plurality of cores 31, 32 that are cylindrical and are arranged so as to be axially movable with respect to the field F on the inner periphery of the field F and are arranged side by side with an axial interval therebetween, and a winding 4 mounted in a slot 3c between the teeth 3b, 3b of the cores 31, 32, and two holders 21, 22 that hold the cores 31, 32 one by one and are provided in the same number as the cores 31, 32 and are axially connected to each other. The holders 21, 22 each have a core mounting portion 21a, 22a on which the cores 31, 32 are mounted and which is axially longer than the cores 31, 32, and an opposing portion 21b, 22b provided on one end side of the core mounting portion 21a, 22a and facing one end side of the cores 31, 32. In all the cores 31, 32, the axial lengths L3, L4 of the core mounting portions 21a, 22a are equal, and the axial lengths LF1, LF2 of the opposing portions 21b, 22b are equal.

[0056] According to the cylindrical linear motor 1 configured as described above, the cores 31 and 32 are mounted on the core mounting portions 21a and 22a that are longer than the axial lengths of the cores 31 and 32 in the corresponding holders 21 and 22, and the holders 21 and 22 are axially connected to each other. Therefore, the cores 31 and 32 are axially positioned by the holders 21 and 22 without being affected by each other's dimensions. Thus, according to the cylindrical linear motor 1 of the present embodiment, even if there are dimensional errors in the axial lengths of the cores 31 and 32, the cores 31 and 32 can be positioned at appropriate positions by correctly managing only the dimensions of the holders 21 and 22.

[0057] Here, when the cores 31 and 32 are manufactured by laminating and bonding pieces that are axially divided in the axial direction, there are dimensional errors for each piece, and dimensional errors also occur in the axial direction of the cores 31 and 32 during the bonding process of the pieces to each other. Therefore, the overall axial length of the cores 31 and 32 often does not match the designed length L1 and includes dimensional errors.

[0058] When arranging the cores 31 and 32 axially with only the interval between the cores 31 and 32 being accurately set to a predetermined length L2 as in a conventional cylindrical linear motor, the dimensional errors of the cores 31 and 32 accumulate throughout the armature 2, and each core 31 and 32 and the field magnet F are not arranged at appropriate positions, resulting in the reduction effect of cogging thrust being diminished. In contrast, in the cylindrical linear motor 1 of the present embodiment, as described above, even if there are dimensional errors in the axial lengths of the cores 31 and 32, the cores 31 and 32 do not affect each other's dimensions, and the dimensional errors of all the cores 31 and 32 are not superimposed in the axial direction of the armature 2. Therefore, by correctly managing only the dimensions of the holders 21 and 22, the displacement in the arrangement of each core 31 and 32 with respect to the field magnet F can be contained within the dimensional errors of each core 31 and 32.

[0059] Therefore, according to the tubular linear motor 1 of the present embodiment, the displacement of the arrangement of each of the cores 31 and 32 with respect to the field magnet F is kept within the dimensional errors of each of the cores 31 and 32, preventing the dimensional errors of all the cores 31 and 32 installed in the armature 2 from overlapping and causing a large displacement in the arrangement of each of the cores 31 and 32 with respect to the field magnet in the whole armature 2. Thus, the cogging thrust caused by the relationship between the number of magnetic poles and the number of slots of the cores 31 and 32 can be suppressed by optimizing the arrangement of the cores 31 and 32. From the above, according to the tubular linear motor 1 of the present embodiment, even if there are dimensional errors in the cores 31 and 32, the cogging thrust can be reduced.

[0060] Furthermore, in the tubular linear motor 1 including the holders 21 and 22 that hold the cores 31 and 32 one by one and are provided in the same number as the cores 31 and 32, the cores 31 and 32 can be positioned by attaching the cores 31 and 32 to the holders 21 and 22 one by one. Therefore, according to the tubular linear motor 1 configured in this way, the manufacture of the tubular linear motor 1 becomes easy.

[0061] Also, in the tubular linear motor 1 of the present embodiment, taking the position of one end 2a in the axial direction of the armature of the cores 31 and 32 as a reference position, setting the reference length obtained by adding the designed axial length L1 of the cores 31 and 32 and a predetermined length L2 as L, and taking the order of the cores 3 counted from the one - end 2a side in the axial direction of the armature as N (where N is an integer of 2 or more), the cores 3 after the N - th core in the axial direction of the armature 2 N are arranged at a distance of (N - 1)×L from the reference position.

[0062] According to the tubular linear motor 1 configured in this way, the N - th core 3 NOne end of it is always positioned at a distance that is (N - 1) times the reference length L from one end 2a on the anti-core side of the first core 31. In this way, in the tubular linear motor 1 of the present embodiment, one end of the cores 32 and later installed in the armature 2 is always arranged at a distance of (N - 1)×L from the reference position based on one end 2a of the anti-core side end of the first core 31. Since the dimensional errors of all the cores 31, 32 do not overlap in the axial direction of the armature 2, the displacement of the arrangement of each core 31, 32 with respect to the field magnet F can be kept within the dimensional errors of each core 31, 32.

[0063] Also, when the cores 31, 32 are formed by laminating pieces divided for each tooth 3b, errors are likely to occur in the axial dimensions of the cores 31, 32 and the designed length L1. However, since it becomes easier to assemble the winding 4 in the slot 3b, the manufacture of the armature 2 becomes easy. Therefore, according to the tubular linear motor 1 of the present embodiment, even when it is desired to facilitate the manufacture of the armature 2 by adopting a manufacturing process of forming the cores 31, 32 with pieces divided in the axial direction, the cogging thrust can be effectively reduced. Even when the cores 31, 32 are not formed with divided pieces but are integrally manufactured, dimensional errors occur in the axial lengths of the cores 31, 32. Therefore, the structure of the tubular linear motor 1 of the present embodiment can also be adopted for a tubular linear motor having an integrally manufactured core to reduce the cogging thrust.

[0064] Furthermore, in the cylindrical linear motor 1 of the present embodiment, the total axial lengths of the holders 21 and 22 in the core mounting portions 21a and 22a and the opposing portions 21b and 22b are equal to the reference length L obtained by adding the axial design lengths of the cores 31 and 32 and a predetermined length. Also, the axial lengths L3 and L4 of the respective core mounting portions 21a and 22a of the holders 21 and 22 are equal to each other, and the axial lengths LF1 and LF2 of the respective opposing portions 21b and 22b are equal to each other. The axial lengths L3 and L4 of the core mounting portions 21a and 22a are longer than the axial lengths of the cores 31 and 32. Therefore, in the state where the holders 21 and 22 are connected, the distance between the contact surfaces (the end faces in FIG. 1 of the respective opposing portions 21b and 22b) where the cores 31 and 32 of the opposing portions 21b and 22b contact is always equal to the reference length L. Thus, after mounting the cores 31 and 32 corresponding to the respective holders 21 and 22, by simply connecting the holders 21 and 22, one end of the second and subsequent cores 32 installed in the armature 2 is always arranged at a distance of (N - 1) × L from one end 2a of the anti-core side end of the first core 31. Therefore, according to the cylindrical linear motor 1 configured in this way, since the dimensional errors of all the cores 31 and 32 are not superimposed in the axial direction of the armature 2, the displacement in the arrangement of each core 31 and 32 with respect to the field F can be accommodated within the dimensional errors of each core 31 and 32.

[0065] Also, as described above, in the cylindrical linear motor 1 of the present embodiment, the predetermined length L2 is set to a length that is an integer multiple of the slot pitch P. By doing so, the cores 31 and 32 can face the magnetic poles of the field F at equal electrical angles, so there is no deviation between the magnet pitch of the field F and the slot pitch of the core 3, and no thrust reduction occurs. Thus, the cylindrical linear motor 1 can be driven by energizing the windings 4 of each core 31 and 32 at the same timing. Therefore, when the predetermined length L2 is set to a length that is an integer multiple of the slot pitch P, there is no thrust reduction, and the windings 4 of each core 31 and 32 can be driven by a single drive circuit.

[0066] Furthermore, in the cylindrical linear motor 1 of the present embodiment, one opposing portion 22b of adjacent holders 21 and 22 is in contact with the other core mounting portion 21a of the adjacent holders 21 and 22. According to the cylindrical linear motor 1 configured in this way, after the cores 31 and 32 are mounted on the core mounting portions 21a and 22a of the corresponding holders 21 and 22, by simply bringing the core mounting portion 21a into contact with the opposing portion 22b to connect the holders 21 and 22, the cores 31 and 32 can be automatically positioned at appropriate positions.

[0067] Also, in the cylindrical linear motor 1 of the present embodiment, the field magnet F is cylindrical, the cores 31 and 32 are arranged on the inner peripheral side of the field magnet F, the core mounting portions 21a and 22a are cylindrical, and the cores 31 and 32 are mounted on the outer periphery. The holders 21 and 22 each have screw holes 21c and 22c that open from the other end sides of the core mounting portions 21a and 22a. The holder 22 that holds the core 32 other than the first core 31 among the holders 21 and 22 is provided with a screw shaft 22d that protrudes from one end side of the opposing portion 22b and is screwed into the screw hole 21c of the adjacent holder 21. According to the cylindrical linear motor 1 configured in this way, after the cores 31 and 32 are mounted on the core mounting portions 21a and 22a of the corresponding holders 21 and 22, by simply screwing the screw shaft 22d into the screw hole 21c to connect the holders 21 and 22, the cores 31 and 32 can be automatically positioned at appropriate positions, and the cylindrical linear motor 1 can be easily manufactured.

[0068] Note that, like the cylindrical linear motor 1A which is a modification of one embodiment shown in FIG. 2, the field magnet F is cylindrical, the cores 31 and 32 are arranged on the inner peripheral side of the field magnet F, the core mounting portions 21a and 22a are cylindrical, and the cores 31 and 32 are mounted on the outer periphery. The holders 21 and 22 have screw shafts 21e and 22e protruding from the other end sides of the core mounting portions 21a and 22a. The holder 22 that holds the core 32 other than the first core 31 among the holders 21 and 22 may have a screw hole 22f that opens from one end side of the opposing portion 22b and into which the screw shaft 21e of the adjacent holder 21 is screwed. The holders 21 and 22 in the cylindrical linear motor 1A of a modification of one embodiment are different from the holders 21 and 22 in the cylindrical linear motor 1 in that the core mounting portions 21a and 22a are provided with screw shafts 21d and 22d instead of screw holes 21c and 22c, and the opposing portion 22b is provided with a screw hole 22f instead of the screw shaft 22d. Regarding other configurations of the cylindrical linear motor 1A which is a modification of one embodiment, they are the same as the configuration of the cylindrical linear motor 1 of one embodiment. According to the cylindrical linear motor 1A which is a modification of one embodiment configured in this way, similar to the cylindrical linear motor 1 of one embodiment, after mounting the cores 31 and 32 on the core mounting portions 21a and 22a of the corresponding holders 21 and 22, by simply screwing the screw shaft 21e into the screw hole 22f to connect the holders 21 and 22, the cores 31 and 32 can be automatically positioned at appropriate positions, and the cylindrical linear motor 1A can be easily manufactured.

[0069] Thus, in the cylindrical linear motors 1 and 1A, the connecting portion includes screw shafts 21f and 22d provided on either one of the core mounting portions 21a and 22a and the opposing portions 21b and 22b, and screw holes 21c and 22e provided on the other of the core mounting portions 21a and 22a and the opposing portions 21b and 22b into which the screw shafts 21f and 22d are screwed. According to the cylindrical linear motors 1 and 1A configured in this way, by simply screwing the screw shaft 21e into the screw hole 22f to connect the holders 21 and 22, the cylindrical linear motors 1 and 1A can be easily manufactured.

[0070] Note that the connecting portion may be composed of a press-fitting shaft portion provided on either one of the core mounting portions 21a and 22a and the opposing portions 21b and 22b, and a hole provided on the other of the core mounting portions 21a and 22a and the opposing portions 21b and 22b into which the press-fitting shaft portion is press-fitted.

[0071] Also, in the tubular linear motors 1 and 1A of the present embodiment, although the shoulder at the tip of the core mounting portion 21a of one holder 21 is brought into contact with the opposing portion 22b of the other holder 22, a stopper such as a flange capable of contacting the opposing portion 22b may be provided at the tip of the core mounting portion 21a. In this way, by simply bringing the stopper, which forms a part of the core mounting portion 21a, into contact with the opposing portion 22b to connect the holders 21 and 22, the cores 31 and 32 can be automatically positioned at appropriate positions. Note that in this case, the connecting portion may be composed of a screw shaft and a screw hole, or may be composed of a press-fitting shaft portion and a hole. The stopper may be provided by attaching a snap ring or the like to the outer periphery of the shaft constituting the core mounting shafts 21a and 22a, and the shape of the stopper can be arbitrarily changed as long as it can function as a stopper.

[0072] Furthermore, the tubular linear motor 1 of the present embodiment has a non-magnetic inner tube (tube) 9 on the inner periphery where the field magnet F is on the armature side, and opposing portions 21b and 22b that are in sliding contact with the inner periphery of the inner tube 9 are provided in the vicinity of the cores 31 and 32 of the armature 2. According to the tubular linear motor 1 configured in this way, since the armature 2 having a plurality of cores 31 and 32 is supported by the opposing portions 21b and 22b, the armature 2 can smoothly move in the axial direction without being eccentric with respect to the field magnet F. Note that when the tubular linear motor 1 adopts a structure in which the armature 2 is arranged on the outer peripheral side of the field magnet F, a non-magnetic tube may be provided on the outer periphery of the field magnet F, and a wear ring that is in sliding contact with the outer periphery of the tube may be provided on the inner periphery of the side where the armature 2 is provided.

[0073] Note that the outer peripheral shapes of the opposing portions 21b and 22b can be arbitrarily changed as long as they function to position the cores 31 and 32 axially by opposing one end of the cores 31 and 32. However, in order to achieve smooth axial movement of the armature 2 by slidingly contacting the inner periphery of the inner tube 9, it is preferably disk-shaped.

[0074] Also, when positioning the cores 31 and 32, since the lengths L3 and L4 of the core mounting portions 21a and 22a are set in advance to the length obtained by subtracting the axial lengths LF1 and LF2 of the opposing portions 21b and 22b from the reference length L, the cores 31 and 32 can be automatically positioned axially by simply connecting the holders 21 and 22. However, a washer that fits onto the outer periphery of the core mounting portions 21a and 22a may be used to finely adjust and position the cores 31 and 32 axially with respect to the core mounting portions 21a and 22a.

[0075] In addition, in the tubular linear motor 1 of the present embodiment, a structure is adopted in which the cylindrical field magnet F is disposed on the outer peripheral side of the armature 2. However, a structure may be adopted in which teeth 3b are provided on the inner peripheral side of the core 3 to form slots 3c in which the windings 4 are mounted on the inner peripheral side of the core 3, and the field magnet F is inserted inside the armature 2.

[0076] As described above, the preferred embodiments of the present invention have been described in detail. However, modifications, deformations, and changes are possible without departing from the scope of the claims.

Explanation of Reference Numerals

[0077] 1 ··· Tubular linear motor, 2 ··· Armature, 2a ··· One end of the armature, 31, 32, 3 N ··· Core, 3b ··· Teeth, 3c ··· Slot, 4 ··· Winding, 12, 21, 22 ··· Holder, 21a, 22a ··· Core mounting portion, 21b, 22b ··· Opposing portion, 21c, 22c ··· Screw hole (connecting portion), 22d ··· Screw shaft (connecting portion), F ··· Field magnet, L ··· Reference length, L1 ··· Design length of the core, L2 ··· Predetermined length, N ··· Number indicating the order of the cores

Claims

1. A field magnet, a plurality of cores that are cylindrical and arranged so as to be axially movable relative to the field magnet and provided side by side in the axial direction around the field magnet side, with a plurality of teeth provided side by side at intervals in the axial direction, and an armature including windings mounted in slots between the teeth of the cores, a plurality of holders that hold the cores one by one and are provided in the same number as the cores and axially connected to each other, each of the holders having a core mounting portion on which the core is mounted and which is axially longer than the core, an opposing portion provided on one end side of the core mounting portion and facing one end side of the core, and a connecting portion that connects the holders to each other, in all of the holders, the axial lengths of the core mounting portions are equal, and the axial lengths of the opposing portions are equal A cylindrical linear motor characterized by the above.

2. Taking the position of one end in the axial direction of the armature as a reference position, setting the reference length obtained by adding the designed axial length of the core and a predetermined length as L, and setting the order of the cores counted from one end side in the axial direction of the armature as N (where N is an integer of 2 or more), the Nth core in the axial direction of the armature from one end side is arranged at a distance of (N - 1) × L from the reference position The cylindrical linear motor according to claim 1, characterized by the above.

3. The total axial length of the core mounting portion and the opposing portion is equal to the reference length obtained by adding the designed axial length of the core and a predetermined length The cylindrical linear motor according to claim 1, characterized by the above.

4. The predetermined length is an integer multiple of the slot pitch in the core The cylindrical linear motor according to claim 2 or 3, characterized by the above.

5. One of the opposing portions of adjacent holders and the other core mounting portion of adjacent holders are in contact with each other The cylindrical linear motor according to any one of claims 1 to 4, characterized by the above.

6. The connecting portion has a screw shaft provided on either one of the core mounting portion and the opposing portion, and a screw hole provided on the other of the core mounting portion and the opposing portion and screwed with the screw shaft The cylindrical linear motor according to any one of claims 1 to 5, characterized by the above.

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