WO2019202758A1

WO2019202758A1 - Cylindrical linear motor

Info

Publication number: WO2019202758A1
Application number: PCT/JP2018/039470
Authority: WO
Inventors: 佐藤　浩介; 隆司柿内
Original assignee: Ｋｙｂ株式会社
Priority date: 2018-04-17
Filing date: 2018-10-24
Publication date: 2019-10-24
Also published as: JP7025533B2; JPWO2019202758A1

Abstract

This cylindrical linear motor (M1) is provided with: a cylindrical field (6) in which N poles and S poles are axially arranged alternately; an inner tube (9) disposed on the inner periphery of the field (6) and made from a non-magnetic material; a rod (11) movably inserted in the inner tube (9); an armature (A) mounted on the rod (11); and sliders (12, 13) provided to the rod (11) and in sliding contact with the inner periphery of the inner tube (9) to guide the movement of the armature (A) relative to the field (6).

Description

Cylindrical linear motor

The present invention relates to a cylindrical linear motor.

For example, as disclosed in JP2009-213192A, a cylindrical linear motor includes a base that extends in a linear direction, and a plurality of cylindrical linear motors that are attached so that S poles and N poles are alternately arranged in the linear direction with respect to the base. And an armature provided so as to be movable in the linear direction with respect to the field.

Specifically, a conventional cylindrical linear motor includes a field magnet including a cylindrical center yoke and a plurality of annular permanent magnets mounted on the outer periphery of the center yoke, a cylindrical core, and an inner portion of the core. It has a coil housed in a plurality of slots provided in the periphery, and an armature into which the field is inserted on the inner periphery side (see, for example, Patent Document 1).

In the conventional cylindrical linear motor, when the magnetic field is increased to improve the thrust, the center yoke is bent by the attractive force generated between the core and the permanent magnet, and the permanent magnet is eccentric with respect to the core. The thrust may be reduced.

Therefore, an object of the present invention is to provide a cylindrical linear motor that can prevent the eccentricity of the armature with respect to the field and can stably generate thrust.

In order to achieve the above object, the cylindrical linear motor of the present invention is cylindrical and is disposed on the inner periphery of the field, in which N poles and S poles are alternately arranged in the axial direction. A non-magnetic inner tube, a rod that is movably inserted into the inner tube, an armature that is mounted on the rod, and is provided on the rod and slidably contacts the inner circumference of the inner tube to prevent the armature field. And a slider for guiding the movement. In the cylindrical linear motor configured as described above, a non-magnetic inner tube is disposed between the field and the armature, and the slider provided on the rod is in sliding contact with the inner periphery of the inner tube. The movement of the armature in the thrust direction is guided and the radial eccentricity with respect to the field is suppressed.

FIG. 1 is a longitudinal sectional view of a cylindrical linear motor in the first embodiment. FIG. 2A is a side view of the inner tube of the cylindrical linear motor in the first embodiment. FIG. 2B is a perspective view of the inner tube of the cylindrical linear motor in the first embodiment. FIG. 3 is a longitudinal sectional view of a tooth portion of the cylindrical linear motor according to the first embodiment. FIG. 4 is a diagram showing a waveform of a single cogging thrust of the core. FIG. 5 is a diagram showing a waveform of a single cogging thrust of the core. FIG. 6 is a diagram showing a waveform of a single cogging thrust of the core. FIG. 7 is a diagram showing a waveform of a single cogging thrust of the core. FIG. 8 is a diagram for explaining a change in the width of the end teeth and a change in the cogging thrust. FIG. 9 is a longitudinal sectional view of a cylindrical linear motor according to a first modification of the first embodiment. FIG. 10 is a longitudinal sectional view of a cylindrical linear motor in a second modification of the first embodiment. FIG. 11A is a side view of the inner tube of the cylindrical linear motor in the second modification of the first embodiment. FIG. 11B is a perspective view of the inner tube of the cylindrical linear motor in the second modification of the first embodiment. FIG. 12 is a longitudinal sectional view of a cylindrical linear motor according to a third modification of the first embodiment. FIG. 13 is a longitudinal sectional view of a cylindrical linear motor in the second embodiment.

Hereinafter, the present invention will be described based on the embodiments shown in the drawings. In addition, the same code | symbol is attached | subjected about the structure which is common in the cylindrical linear motor M1, M2, M3, M4, M5 of each embodiment demonstrated below, and in order to avoid duplication of description of one embodiment. A detailed description of the configuration described in the description of the cylindrical linear motor M1 will be omitted in the description of the cylindrical linear motors M2, M3, M4, and M5 of the other embodiments.

<First embodiment>
As shown in FIG. 1, the cylindrical linear motor M 1 in the first embodiment is a cylindrical field 6 in which N poles and S poles are alternately arranged in the axial direction, A non-magnetic inner tube 9 disposed on the inner periphery, a rod 11 movably inserted into the inner tube 9, an armature A attached to the rod 11, and an inner tube 9 provided on the rod 11 And

sliders

12 and 13 for guiding the movement of the armature A with respect to the field 6.

Hereinafter, each part of the cylindrical linear motor M1 will be described in detail. First, the armature A that is a mover will be described. The armature A includes two

cores

2A and 2B in the present embodiment. The cores 2 A and 2 B have the same shape, and are configured to include a cylindrical yoke 3 and a plurality of

teeth

4 a and 4 b that are annular and provided on the outer periphery of the yoke 3. It is mounted side by side in the axial direction and is a mover. That is, in the cylindrical linear motor M1, the armature A is driven as a mover, and the axial direction of the

cores

2A and 2B is the thrust generation direction.

As shown in FIG. 1, the yoke 3 in each of the

cores

2A and 2B has a cylindrical shape, and a plurality of

teeth

4a and 4b provided at intervals in the axial direction are provided on the outer periphery thereof. In the present embodiment, as shown in FIG. 1, ten

teeth

4a and 4b are arranged on the outer periphery of the yoke 3 at equal intervals in the axial direction, and between the

teeth

4a and 4b and between the

teeth

4b and 4b. A slot 18 is formed which is a gap in which the winding 5 is mounted.

The

teeth

4a and 4b are composed of two

end teeth

4a and 4a provided to be arranged at both ends of the yoke 3, and eight intermediate teeth 4b provided to be provided between the

end teeth

4a and 4a. Has been. That is, the

end teeth

4a and 4a are provided at both ends in the axial direction as the moving direction of the core 2A (2B) with respect to one core 2A (2B), and the intermediate teeth 4b are provided between the

end teeth

4a and 4a. ing. In the present embodiment, the end teeth 4a and the intermediate teeth 4b are annular.

In the present embodiment, as shown in FIG. 3, the intermediate teeth 4b are formed in an isosceles trapezoidal shape in which the width y at the outer peripheral end is narrower than the width yi at the inner peripheral end in the axial direction. Is a tapered surface inclined at an equal angle with respect to the outer peripheral end. And in the cross section which cut | disconnected the intermediate teeth 4b in the surface containing the axis line J of the

cores

2A and 2B, the internal angle (theta) which the side surface of the intermediate teeth 4b makes with the orthogonal surface O orthogonal to the axis line J of the

cores

2A and 2B is 6 degrees. Is set to an angle within a range of 12 degrees.

Further, as shown in FIG. 3, the end teeth 4a have a side surface on the intermediate teeth side that has the same shape as the side surface of the intermediate teeth 4b and a side surface on the anti-intermediate teeth side that is perpendicular to the axis J with respect to the

cores

2A and 2B. It has a trapezoidal shape. That is, the side surface of the end teeth 4a on the side of the intermediate teeth is a tapered surface, and the internal angle θ formed by this side surface with the orthogonal surface O orthogonal to the axis J of the

cores

2A and 2B is the side surface of the intermediate tooth 4b. It is equal to the internal angle θ formed with O. Further, the side surface on the anti-intermediate teeth side of the end tooth 4a is a surface orthogonal to the axis J of the

cores

2A and 2B, and the angle formed between the side surface and the outer peripheral end is 90 degrees.

Further, in the present embodiment, the gaps between the

adjacent teeth

4a and 4b in FIG. 1 in each of the

cores

2A and 2B, that is, between the end teeth 4a and the intermediate teeth 4b and between the

intermediate teeth

4b and 4b. A total of 18 slots 18 are provided. The windings 5 are wound around all the slots 18 and attached. The winding 5 is a U-phase, V-phase, and W-phase three-phase winding. In each of the 18 slots 18 of each of the

cores

2A and 2B, the W phase, the W phase, the W phase and the V phase, the V phase, the V phase, the V phase, the U phase, and the U phase are sequentially arranged from the left side in FIG. , U phase, U phase and W phase, W phase and V phase, V phase, V phase, V phase and U phase, U phase, U phase, U phase and W phase, W phase, W phase winding 5 It is installed.

The

cores

2A and 2B configured as described above are mounted on the outer periphery of the rod 11 formed of a nonmagnetic material that is an output shaft. Specifically, the cores 2 A and 2 B are fixed to the rod 11 by being sandwiched between

annular sliders

12 and 13 that are fixed to the outer periphery of the rod 11. Wear rings 12 a and 13 a are mounted on the outer circumferences of the

sliders

12 and 13. In addition, a spacer 14 made of a non-magnetic material fixed to the outer periphery of the rod 11 is interposed between the

cores

2A and 2B. The core 2A and the core 2B are fixed to the rod 11 with an interval K therebetween. Has been. Further, the outer diameters of the

sliders

12 and 13 and the spacer 14 are set larger than the outer diameters of the

cores

2A and 2B. The armature A thus configured is inserted into the cylindrical field 6 so as to be movable in the axial direction, which is the thrust direction. In the case of the present embodiment, the spacer 14 provides a magnetic gap with an interval K between the core 2A and the core 2B.

In FIG. 1, the relative rotation around the rod 11 is restricted by the pin 24 fitted to both the left core 2A and the left slider 12 as well as the left slider 12. In addition, the relative rotation around the rod 11 is restricted by the pin 25 fitted to both the right core 2B and the right core 2B in FIG. Furthermore, relative rotation around the rod 11 is restricted by the pin 26 fitted to both the core 2A and the spacer 14, and the rod 11 is fitted to the core 2B and the spacer 14 by the pin 27 fitted to both. The relative rotation around is restricted. In the present embodiment, the rotation restricting portions that restrict the relative rotation of the

sliders

12 and 13 and the armature A around the rod 11 are the

pins

24 and 25. The spacer rotation restricting portions for restricting the relative rotation of the spacer 14 and the

cores

2A, 2B around the rod 11 are

pins

26, 27. The rotation restricting portion and the spacer rotation restricting portion are not limited to the

pins

24, 25, 26, and 27, and the structure is not limited as long as the relative rotation can be restricted. Therefore, for example, when the

sliders

12 and 13, the cores 2 A and 2 B and the spacer 14 are prevented from rotating with respect to the rod 11, the relative rotation of the

sliders

12 and 13, the cores 2 A and 2 B and the spacer 14 is restricted. The restricting portion may employ a rotation prevention mechanism such as a key, a key groove, a spline, and a serration. As described above, the rotation restricting portion and the spacer rotation restricting portion may function as a circumferential detent of the

sliders

12 and 13, the cores 2 A and 2 B, and the spacer 14 with respect to the rod 11.

Further, a regulating member 28 having a protrusion protruding in the radial direction from the outer periphery of the slider 13 when the rod 11 is viewed from the axial direction is attached to the slider 13 on the right side in FIG. The restricting member 28 may be inserted into a notch 9a of the inner tube 9 to be described later and may not interfere with the

permanent magnets

10a and 10b, and may be fixedly attached to the rod 11. Therefore, it may be directly attached to the rod 11 without using the slider 13, and various methods such as screw fastening and welding can be adopted for the attachment.

On the other hand, in this embodiment, the stator S includes an outer tube 7 formed of a cylindrical nonmagnetic material, and a back yoke 8 formed of a cylindrical soft magnetic material inserted into the outer tube 7. The field magnet 6 includes a ring-shaped main magnetic pole permanent magnet 10a and a ring-shaped sub-magnetic pole permanent magnet 10b inserted into the back yoke 8 alternately in the axial direction. A nonmagnetic inner tube 9 is provided on the inner periphery of the

permanent magnets

10a and 10b of the field 6. That is, the

permanent magnets

10 a and 10 b are accommodated in an annular gap between the back yoke 8 and the inner tube 9.

In FIG. 1, the triangular marks on the main magnetic pole permanent magnet 10a and the sub magnetic pole permanent magnet 10b indicate the magnetization direction, and the magnetization direction of the main magnetic pole permanent magnet 10a is the radial direction. Thus, the magnetization direction of the secondary magnetic pole permanent magnet 10b is the axial direction. The permanent magnet 10a of the main magnetic pole and the permanent magnet 10b of the sub magnetic pole are arranged in a Halbach array, and are arranged on the inner peripheral side of the field magnet 6 so that S poles and N poles appear alternately in the axial direction. .

The axial length L1 of the main magnetic pole permanent magnet 10a is longer than the axial length L2 of the auxiliary magnetic pole permanent magnet 10b. In this embodiment, 0.2 ≦ L2 / L1 ≦ 0. .5, the axial length L1 of the main magnetic pole permanent magnet 10a and the axial length L2 of the auxiliary magnetic pole permanent magnet 10b are set. If the axial length L1 of the main pole permanent magnet 10a is increased, the magnetic resistance between the main pole permanent magnet 10a and the

core

2A, 2B can be reduced, and the magnetic field applied to the

core

2A, 2B can be increased. Therefore, the thrust of the cylindrical linear motor M1 can be improved. Further, in the cylindrical linear motor M1 of the present embodiment, the axial length of the permanent magnet 10a of the main magnetic pole is made longer than the axial length of the permanent magnet 10b of the auxiliary magnetic pole, thereby improving the thrust of the cylindrical linear motor M1. However, the axial lengths of the

permanent magnets

10a and 10b can be arbitrarily changed. Moreover, the field 6 may be comprised with the permanent magnet arrange | positioned by arrangement | sequences other than Halbach arrangement | sequence.

Further, in the cylindrical linear motor M1 of the present invention, the back yoke 8 is provided on the outer periphery of the

permanent magnets

10a and 10b. When the back yoke 8 is provided, a magnetic path having a low magnetic resistance can be secured even if the axial length L2 of the secondary magnetic pole permanent magnet 10b is shortened. Therefore, when the axial length L1 of the main magnetic pole permanent magnet 10a is increased. The thrust of the cylindrical linear motor M1 can be effectively improved. More specifically, if the back yoke 8 is provided on the outer periphery of the

permanent magnets

10a and 10b, a magnetic path having a low magnetic resistance can be secured, so that an increase in the magnetic resistance due to the shortening of the axial length L2 of the permanent magnet 10b of the auxiliary magnetic pole. Is suppressed. Therefore, when the axial length L1 of the permanent magnet 10a of the main magnetic pole is made longer than the axial length L2 of the permanent magnet 10b of the auxiliary magnetic pole, and the cylindrical back yoke 8 is provided on the outer periphery of the

permanent magnets

10a, 10b, the cylinder The thrust of the mold linear motor M1 can be greatly improved. 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 main magnet permanent magnet 10a. Although the increase in magnetic resistance can be suppressed by providing the back yoke 8, the back yoke 8 can be omitted.

The sub-magnetic pole permanent magnet 10b is a permanent magnet having a higher coercive force than the main magnetic pole permanent magnet 10a. The residual magnetic flux density and coercive force of a permanent magnet are closely related to each other. Generally, increasing the residual magnetic flux density decreases the coercive force, and increasing the coercive force decreases the residual magnetic flux density. There is a relationship. In the Halbach array, since a large magnetic field is applied in the demagnetization direction to the secondary magnetic pole permanent magnet 10b, the coercive force of the secondary magnetic pole permanent magnet 10b is increased to suppress the demagnetization, and the large magnetic field is applied to the

cores

2A and 2B. To be able to act on. On the other hand, the strength of the magnetic field acting on the

cores

2A and 2B depends on the number of lines of magnetic force of the permanent magnet 10a of the main magnetic pole. Therefore, a large magnetic field is applied to the

cores

2A and 2B by using a permanent magnet having a high residual magnetic flux density for the permanent magnet 10a of the main magnetic pole. In this embodiment, when the coercive force of the secondary magnetic pole permanent magnet 10b is made higher than that of the main magnetic pole permanent magnet 10a, the material of the secondary magnetic pole permanent magnet 10b is made to be more coercive than the material of the main magnetic pole permanent magnet 10a. There are high materials. Therefore, the combination of the main magnetic pole permanent magnet 10a and the auxiliary magnetic pole permanent magnet 10b can be easily realized by selecting the material. In the present embodiment, the main magnetic pole permanent magnet 10a is made of a material having a high residual magnetic flux density mainly composed of neodymium, iron, and boron, and the auxiliary magnetic pole permanent magnet 10b is made of dysprosium or terbium. It is made up of magnets that are hard to demagnetize with increased amounts of heavy rare earth elements such as.

Further, an armature A is inserted on the inner peripheral side of the stator S, and the field 6 causes a magnetic field to act on the armature A. In addition, since the field 6 should just apply a magnetic field with respect to the movable range of the armature A, what is necessary is just to determine the installation range of

permanent magnet

10a, 10b according to the movable range of the armature A. Therefore, it is not necessary to install the

permanent magnets

10a and 10b in the range where the armature A cannot be opposed to the annular gap between the outer tube 7 and the inner tube 9. The length of the back yoke 8 is equal to the length of the

permanent magnets

10a and 10b stacked, and the

permanent magnets

10a and 10b cause a magnetic force to act outside the stroke range of the

cores

2A and 2B, thereby reducing thrust. It is considered not to invite.

Further, the left end in FIG. 1 of the outer tube 7, the back yoke 8 and the inner tube 9 is closed by a cap 15, and the right end in FIG. 1 of the outer tube 7, the back yoke 8 and the inner tube 9 is closed by an annular head cap 16. It is blocked. The head cap 16 has an inner diameter larger than the outer diameter of the rod 11, and includes a dust seal 16 a on the inner periphery, and the rod 11 is inserted through the inner periphery. And the dust seal | sticker 16a is slidably contacted with the outer periphery of the rod 11 inserted in the inner periphery of the head cap 16, and seals the outer periphery of the rod 11. FIG.

As shown in FIGS. 1 and 2, the inner tube 9 includes a notch 9a that opens from the right end in the drawing and is provided along the axial direction. Further, on the inner periphery of the inner tube 9, an armature A,

sliders

12, 13 and a spacer 14 mounted on the outer periphery of the rod 11 and the rod 11 are inserted so as to be movable in the axial direction. Further, a protrusion on the regulating member 28 is inserted into the notch 9 a of the inner tube 9. As described above, when the armature A is inserted into the field 6, the

cores

2A and 2B face the eight magnetic poles in the field 6, so that the cylindrical linear motor M1 is an eight-pole nine-slot linear motor. ing.

Further,

sliders

12 and 13 having wear rings 12 a and 13 a are in sliding contact with the inner peripheral surface of the inner tube 9, and the armature A is eccentric with respect to the field 6 together with the rod 11 by the

sliders

12 and 13. Without moving smoothly in the axial direction.

The lead-in

chamfers

12c and 13c are formed by chamfering the outer peripheries at both ends in the axial direction of the

sliders

12 and 13, respectively. When the

sliders

12 and 13 are provided with the lead in

chamfers

12 c and 13 c at both ends in the axial direction as described above, the

sliders

12 and 13 are inclined with respect to the inner tube 9 due to external moment and lateral force acting on the rod 11. However, it is possible to prevent the

sliders

12 and 13 from rubbing the inner peripheral surface of the inner tube 9 and roughening the inner peripheral surface of the inner tube 9. Therefore, the cylindrical linear motor M1 can be smoothly expanded and contracted over a long period of time.

Since the restricting member 28 is inserted into the notch 9a provided in the inner tube 9 along the axial direction, the armature A moves in the axial direction while restricting the rotation of the armature A in the circumferential direction. I can't interfere. The width of the protrusion inserted into the notch 9a of the restricting member 28 is slightly smaller than the circumferential width of the notch 9a, so that the restricting member 28 can move smoothly within the notch 9a, and the resistance of movement of the armature A It is considered not to become. The total length of the notch 9a provided in the inner tube 9 is such that the regulating member 28 does not collide with the inner wall of the end portion of the notch 9a of the inner tube 9 even when the armature A strokes the maximum in the inner tube 9. ing.

The inner tube 9 forms a gap between the outer periphery of the armature A and the inner periphery of the

permanent magnets

10a and 10b, and cooperates with the

sliders

12 and 13 to guide the axial movement of the armature A. Plays. Thus, since the eccentricity of the armature A is prevented with respect to the field 6, the thrust drop due to the eccentricity of the armature A is also prevented, and the cylindrical linear motor M1 can stably generate the thrust. In this embodiment, the spacer 14 is not slidably contacted with the inner periphery of the inner tube 9. However, even if the rod 11 bends due to an excessive external force acting on the rod 11, the

core

2A, 2B Prior to contact with the inner tube 9. Therefore, interference with the inner tube 9 of the

cores

2A and 2B is prevented, and the armature A can be protected.

The inner tube 9 only needs to be formed of a non-magnetic material, but if formed of synthetic resin, the effect of improving the thrust density of the cylindrical linear motor M1 is enhanced. When the inner tube 9 is made of a non-magnetic metal, an eddy current is generated in the inner tube 9 when the armature A moves in the axial direction, and a force that hinders the movement of the armature A is generated. On the other hand, if the inner tube 9 is made of synthetic resin, no eddy current is generated, so that the thrust of the cylindrical linear motor M1 can be improved more effectively and the mass of the cylindrical linear motor M1 can be reduced. When the inner tube 9 is made of synthetic resin, friction and wear between the

sliders

12 and 13 and the wear rings 12a and 13a can be reduced if the inner tube 9 is made of fluororesin. Further, the inner tube 9 may be formed of another synthetic resin, and the inner periphery of the inner tube 9 formed of another synthetic resin may be coated with a fluororesin so as to reduce friction and wear.

Since the

sliders

12 and 13 provided at both ends of the armature A are slidably contacted with the inner tube 9 as described above, the armature A is prevented from being eccentric with respect to the field 6 and the axial direction of the armature A (thrust direction). ) Is ensured, and the cylindrical linear motor M1 can stably generate thrust. Further, since the cylindrical linear motor M1 includes a non-magnetic inner tube 9 on the inner periphery of the field 6, the armature is inserted when the armature A is inserted into the field 6 of the cylindrical linear motor M1. It is possible to prevent A from being attracted and stuck to the

permanent magnets

10a and 10b. Therefore, when the inner tube 9 is provided, the situation in which the armature A is attracted and stuck to the

permanent magnets

10a and 10b and the assembly of the cylindrical linear motor M1 becomes impossible is avoided, and the cylindrical linear motor M1 is avoided. Assembling work becomes easy.

In the present embodiment, the

sliders

12 and 13 are slidably contacted with the inner tube 9 to guide the prevention and movement of the armature A with respect to the field 6, but the spacer 14 is slidably contacted with the inner tube 9. The eccentricity and movement of the armature A may be guided together with the

sliders

12 and 13. In addition, a cylindrical bearing that is in sliding contact with the outer periphery of the rod 11 may be provided on the inner periphery of the head cap 16 to guide the prevention and movement of the armature A together with the

sliders

12 and 13.

The axial lengths of the outer tube 7, the back yoke 8, and the inner tube 9 are longer than the axial length of the armature A, and the armature A is within the range of the axial length in the field 6. Stroke from left to right.

Further, the cap 15 is provided with a connector 15a for connecting the cable C connected to the winding 5 to an external power supply (not shown) so that the winding 5 can be energized from the external power source. Specifically, the winding 5 is a U-phase, V-phase, and W-phase three-phase winding as described above and is mounted in the slot 18 of the

cores

2A and 2B as described above. The windings 5 of each phase are connected via a lead wire 5b.

The windings 5 having the same phase mounted in the slots 18 provided in the

same cores

2A and 2B are connected to each other by a jumper 5a. The connecting wire 5a of the core 2A is disposed so as to cross the outer periphery of the core 2B in the axial direction through the through hole 14a penetrating the spacer 14 in the axial direction. Further, the connecting wire 5a from each phase winding 5 attached to the core 2A and the connecting wire 5a from each phase winding 5 attached to the core 2B are taken out through the through holes 13b of the slider 13, respectively. Are connected.

Thus, the U-phase, V-phase and W-phase windings 5 of the

cores

2A and 2B are each Y-connected, and the connection point is a neutral point. That is, the in-phase windings 5 of the core 2A are connected in series for each phase by the connecting wire 5a, and the in-phase windings 5 of the core 2B are connected in series for each phase by the connecting wire 5a. The winding 5 of the core 2B is connected in parallel to the external power supply. As described above, the winding 5 of the core 2A and the winding 5 of the core 2B are connected in parallel to the external power supply, so that a voltage can be efficiently applied to the windings 5 of the

cores

2A and 2B and a large current can be supplied. The thrust of the cylindrical linear motor 1 can be improved. In addition, each phase of the

cores

2A and 2B may be connected in series with the same phase.

Further, the windings 5 of each phase attached to the core 2A and the windings 5 of each phase attached to the core 2B are connected to the lead wire 5b connected to the external cable C through the through hole 12b of the slider 12. The Therefore, power can be supplied from the external power supply to the winding 5 of each phase via the cable C. As described above, the crossover 5 a extends from the left side of the slider 12 to the right side of the slider 13. In addition, the lead wire 5b connected to the winding 5 of the core 2B is disposed so as to cross the outer periphery of the core 2A. When the

sliders

12 and 13 and the spacer 14 and the

cores

2A and 2B rotate relative to each other, a load such as a tension acts on the connecting wire 5a and the lead wire 5b. However, the

sliders

12 and 13 and the spacer 14 and the

cores

2A and 2B are connected to Since the relative rotation around the rod 11 is restricted by the

rods

25, 26 and 27, the load such as the tension does not act on the connecting wire 5a and the lead wire 5b, so that the connecting wire 5a and the lead wire 5b are prevented from being disconnected. Occurrence of a situation in which the power supply to 5 becomes impossible can be prevented.

Also, since the armature A is restricted from rotating in the circumferential direction with respect to the inner tube 9 by the notch 9a provided in the inner tube 9 and the regulating member 28, there is no fear that the cable C is twisted and disconnected.

For example, if the electrical angle of the winding 5 with respect to the field 6 is sensed, the energization phase is switched based on the electrical angle, and the current amount of each winding 5 is controlled by PWM control, the cylindrical linear motor M1. And the moving direction of the armature A can be controlled. The above-described control method is an example and is not limited to this. Thus, in the cylindrical linear motor M1 of the present embodiment, the armature A is a mover, and the field 6 behaves as a stator. Further, when an external force that relatively displaces the armature A and the field 6 acts in the axial direction, a thrust that suppresses the relative displacement by energizing the winding 5 or an induced electromotive force generated in the winding 5. Can be generated to cause the cylindrical linear motor M1 to dampen the vibration and movement of the device due to the external force, and energy regeneration that generates electric power from the external force is also possible.

Here, in FIG. 3, when the axial width of the outer peripheral end of the end teeth 4a is W, the axial width of the outer peripheral end of the intermediate teeth 4b is y, and x is a positive value, the outer end of the end teeth 4a The width W in the axial direction is W = (y / 2) + x. That is, the width W of the end teeth 4a is set to y / 2 or more. Since the width of the outer peripheral end of the intermediate tooth 4b is y, the width W of the outer peripheral end of the end tooth 4a needs to be y / 2 or more from the viewpoint of the magnetic path cross-sectional area. When x is 0, that is, when the axial length of the

cores

2A and 2B when the width W of the end teeth 4a is y / 2, the basic length of the

cores

2A and 2B, The basic length is set to 8 times the magnetic pole pitch P of the field 6. Here, the magnetic pole pitch P is set as shown in FIG.

When the width W of the outer peripheral edge of the end tooth 4a is set to W = y / 2 + x as described above and x is changed, the cogging thrust due to the end effect of the

cores

2A and 2B changes. If the value of x is 0, that is, if the

cores

2A and 2B are the basic length, the cogging thrust with respect to the position (deg) of the

cores

2A and 2B with respect to the field 6 is not a clean sine wave, as shown in FIG. In this manner, the

unit

2A, 2B has a waveform in which a unit wave that is disturbed for two periods appears in a range from 0 degrees to 360 degrees (corresponding to two magnetic pole pitches). Since the end effect appears at the left and right end teeth 4a of the

cores

2A and 2B, the cogging thrust of the

cores

2A and 2B is a combination of the end effect cogging thrusts of the left and right end teeth 4a.

Then, as the value of x is increased, the unit wave in the cogging thrust waveform gradually changes so as to approach a sine wave, and the cogging thrust waveform becomes a substantially clean sine waveform at a certain value x1. At this certain value x1, as shown in FIG. 5, the waveform of the cogging thrust is a waveform in which the sine wave appears for two cycles when the positions of the

cores

2A and 2B are in the range from 0 degrees to 360 degrees.

When the value of x is further increased from x1, the waveform of the cogging thrust is disturbed and does not become a sine wave, and as shown in FIG. 6, the positions of the

cores

2A and 2B are 4 in the range from 0 degrees to 360 degrees. It becomes a waveform in which a unit wave that is disturbed for a period appears. As the value of x is further increased, the cogging thrust waveform gradually changes so as to approach a sine waveform, and a substantially clean sine waveform is obtained at a certain value x2. At this certain value x2, as shown in FIG. 7, when the positions of the

cores

2A and 2B are in the range of 0 to 360 degrees, the cogging thrust waveform is a waveform in which a sine wave appears for four cycles.

When the value of x is further increased from x2, the waveform of the cogging thrust is disturbed and does not become a sine wave, and the unit wave that is disturbed for 8 periods in the range of the positions of the

cores

2A and 2B from 0 degree to 360 degrees. Will eventually appear, but eventually a nearly clean sine wave will appear for 8 cycles.

As described above, the cogging thrust waveform of each of the

cores

2A and 2B changes depending on the value of x, and there is a value of x where the waveform of the cogging thrust becomes a sine wave. The position of the

cores

2A and 2B increases as the value of x increases. In the range from 0 degrees to 360 degrees, the number of cogging thrust waveforms increases.

When the value of x is x1 or x2, the cogging thrust waveform of each

core

2A, 2B is a clean sine wave. Therefore, if the interval between the core 2A and the core 2B is adjusted so that the sine waveform of the cogging thrust of the core 2B has an opposite phase to the sine waveform of the cogging thrust of the core 2A, the cogging thrust of the core 2A can be reduced. The overall cogging thrust of the armature A can be minimized by canceling with the cogging thrust of 2B.

When the waveform of the cogging thrust is a waveform in which two sine waves appear when the positions of the

cores

2A and 2B are in the range of 0 degrees to 360 degrees, the core 2A can be canceled by canceling the cogging thrust of the core 2A with the cogging thrust of the core 2B. On the other hand, the core 2B may be separated by 90 degrees or 270 degrees in the axial direction. Generally speaking, the core 2B may be separated from the core 2A by the frequency obtained by calculating 90 + 180n (where n = 0, 1, 2,...). Of the width W of the end teeth 4a of the

cores

2A and 2B, the length x does not affect the electrical angle. Therefore, to separate the core 2B from the core 2A in the axial direction by (90 + 180n) degrees, when the length of the interval between the core 2A and the core 2B is K, and K = z−2x, the value z May be set to a length that causes a shift of (90 + 180n) degrees. 90 degrees is a length corresponding to P / 2 when the magnetic pole pitch is P, and 270 degrees is a length corresponding to 3P / 2. Therefore, the value z may be a value that satisfies (1 + 2n) P / 2 (where n = 0, 1, 2,...).

When the waveform of the cogging thrust is a waveform in which four sine waves appear when the positions of the

cores

2A and 2B are in the range from 0 degrees to 360 degrees, the core 2A can be canceled by canceling the cogging thrust of the core 2A with the cogging thrust of the core 2B. The core 2B may be separated by 45 degrees, 135 degrees, 225 degrees, or 315 degrees in the axial direction with respect to 2A. Generally speaking, the core 2B may be separated from the core 2A by the frequency obtained by calculating 45 + 90n (where n = 0, 1, 2,...). Since the basic lengths of the

cores

2A and 2B are set to an integral multiple of the magnetic pole pitch P, the core 2B can be separated from the core 2A in the axial direction by (45 + 90n) degrees between the core 2A and the core 2B. When the length of the interval is K and K = z−2x, the value z may be set to a length that causes a shift of (45 + 90n) degrees. For example, 45 degrees is a length corresponding to P / 4 when the magnetic pole pitch is P, and 135 degrees is a length corresponding to 3P / 4. Therefore, the value z may be a value satisfying (1 + 2n) P / 4 (where n = 0, 1, 2,...).

In this way, the width W of the end teeth 4a is set with the value of x being x1 or x2, the value of z is obtained based on the value of x, and the interval K between the core 2A and the core 2B is set from the value z. For example, the cogging thrust of the armature A can be minimized. In order to reduce the cogging thrust of the armature A, it is better to set the value of x to a value in which the waveform of the single cogging thrust of the

cores

2A and 2B is a sine wave. Even if it is not set, the cogging thrust of the entire armature A can be reduced.

The result of examining how the entire cogging thrust of the armature A changes according to the value of x on the condition that the interval K is appropriately set according to the value of x so that the cogging thrust can be reduced. As shown in FIG. FIG. 8 shows the overall cogging thrust of the armature A relative to the change in the value of x with reference to the cogging thrust of the entire armature A when the width W of the outer peripheral end of the end tooth 4a is y / 2. It is the graph which showed how it changed. In the graph of FIG. 8, when the value of x is less than x2, the value z is (1 + 2n) P / 2 (where n = 0, 1, 2,...), And the value of x is greater than or equal to x2. In some cases, the value z is expressed as (1 + 2n) P / 4 (where n = 0, 1, 2,...).

As can be understood from FIG. 8, if the width W of the outer peripheral end of the end tooth 4a is larger than y / 2, the cogging thrust of the cylindrical linear motor M1 is lowered. Therefore, if the axial width W of the outer peripheral end of the end tooth 4a is set so as to satisfy W> y / 2, the cogging thrust of the cylindrical linear motor M1 can be reduced. Further, as shown in FIG. 8, when the vertical axis is cogging thrust and the value of x is taken on the horizontal axis, the cogging thrust is a value x1, x2 at which the waveform of the single cogging thrust of the

cores

2A and 2B becomes a sine wave. It changes to take the minimum value periodically.

As described above, when the width W of the end teeth 4a of the

cores

2A and 2B is y / 2 + x, the single cogging thrust waveform of the

cores

2A and 2B varies from 0 degree to 360 degrees depending on the value of x. Since it can be understood how many unit waves appear in the range of degrees, the entire cogging thrust of the armature A can be reduced by optimizing the interval K based on the value of x. Further, if the value of x is optimized and the waveform of the single cogging thrust of the

cores

2A and 2B is a sine wave, the cogging thrust of the armature A can be minimized.

Therefore, when the width W of the end teeth 4a is W = y / 2, the basic length, which is the axial length of the

cores

2A and 2B, is set to an integral multiple of the magnetic pole pitch P, and the width W of the end teeth 4a is set as the cogging thrust. The cogging thrust can be reduced by setting the width to be suitable for reduction and appropriately setting the interval K between the

cores

2A and 2B based on the value of x.

In the case of the present embodiment, a gap 14 is magnetically provided between the core 2A and the core 2B by the spacer 14, and the axial width of the spacer 14 is set to the gap K. Therefore, the value of z may be obtained based on the value of x, and K = z-2x may be calculated to determine the width of the spacer 14 in the axial direction. When the spacer 14 is omitted, the

cores

2A and 2B may be fixed to the outer periphery of the rod 11 while being separated from each other in the axial direction by a distance K.

As described above, the value x is optimal if it is set to x1 and x2 that minimize the cogging thrust. For example, the cogging thrust is 50 with respect to the cogging thrust when the width W is y / 2. % May be set so as to obtain a value within a range of% or less. Even with this setting, the cogging thrust of the cylindrical linear motor M1 is halved from the cogging thrust when the width W of the end teeth 4a is set to y / 2, so that a sufficient cogging thrust reduction effect can be obtained. In the example shown in FIG. 8, when the value of x is in the range β1 or in the range β2, the cogging thrust is 50% with respect to the cogging thrust when the width W is y / 2. (Line shown by a broken line in FIG. 8) or less, the value of x may be set to a value in the range β1 or β2. The cogging thrust takes a minimum value periodically when the width W of the outer peripheral end of the end teeth 4a changes. Therefore, the cogging thrust is 50% or less with respect to the cogging thrust when the width W is y / 2. It may be set so as to obtain a value within a certain range. However, since the masses of the

cores

2A and 2B increase as the width of the end teeth 4a increases, there are various ranges of the value of x that can reduce the cogging thrust. However, as shown in FIG. Should be as small as possible. Therefore, when the value x is set to take a value between 1% of the width y of the outer peripheral edge of the intermediate teeth 4b and the length of the slot pitch, cogging is not caused without causing an unnecessary increase in the mass of the

cores

2A and 2B. Thrust can be reduced. In other words, the width W of the outer peripheral end of the end teeth 4a is set to satisfy y / 2 + 0.01y ≦ W ≦ y / 2 + S, where S is the slot pitch length, and the

cores

2A and 2B are useless. The cogging thrust can be reduced without increasing the mass. The width W needs to be y / 2 or more from the viewpoint of the magnetic path cross-sectional area, and when the slot pitch length S is added to the value of y / 2, which is the minimum necessary width, the width W becomes y / 2. It becomes the same state as the case. Therefore, if it is set to satisfy y / 2 + 0.01y ≦ W ≦ y / 2 + S, unnecessary mass increase of the

cores

2A and 2B is not caused.

In addition, as described above, the armature A includes the two

cores

2A and 2B. However, like the cylindrical linear motor M2 of the first modification of the first embodiment shown in FIG. When the child A includes the three

cores

2A, 2B, and 2C, the following may be performed. In this case, spacers 14A and 14B are provided between the

cores

2A and 2B and between the cores 2B and 2C, so that there is a magnetic gap with a gap K between the

cores

2A and 2B and between the cores 2B and 2C. Provided.

The spacers 14A and 14B have outer diameters larger than the outer diameters of the

cores

2A, 2B and 2C. Therefore, the spacers 14A and 14B, like the spacer 14, perform the function of providing a magnetic gap between the

cores

2A and 2B and between the cores 2B and 2C, and also the inner tube even if the rod 11 is bent by an excessive external force. 9 and the

core

2A, 2B, 2C function to block interference. The spacers 14 A and 14 B may always be in sliding contact with the inner periphery of the inner tube 9 and guide the movement of the armature A in the thrust direction together with the

sliders

12 and 13.

If the value of x is x1 and the position of each

core

2A, 2B, 2C is in the range of 0 to 360 degrees and the waveform of the cogging thrust is a sine wave for two cycles, three

cores

2A, 2B, 2C are provided. If the value z is set to a length that causes a deviation of 60 + 180n (where n = 0, 1, 2,...) Degrees, the cogging thrusts of the

cores

2A, 2B, and 2C cancel each other. The cogging thrust of the armature A can be minimized. That is, the value z may be set to a value that satisfies (1 + 3n) P / 3 (where n = 0, 1, 2,...).

Further, assuming that the value of x is x2 and the waveform of cogging thrust is a waveform in which four sine waves appear in the range of the positions of the

cores

2A, 2B, and 2C from 0 degree to 360 degrees, the three

cores

2A, 2B, and 2C are provided. If the value z is set to a length that causes a deviation of 30 + 90n (where n = 0, 1, 2,...) Degrees, the cogging thrusts of the

cores

2A, 2B, and 2C cancel each other. The cogging thrust of the armature A can be minimized. That is, the value z may be set to a value that satisfies (1 + 3n) P / 6 (where n = 0, 1, 2,...).

In this way, the width W of the end teeth 4a is set with the value of x as x1 or x2, and the value of z is obtained based on the value of x, and between the

cores

2A and 2B and between the cores 2B and 2C from the value z. If the interval K is set, the cogging thrust of the armature A can be minimized. In order to reduce the cogging thrust of the armature A, it is better to set the value of x to a value in which the waveform of the single cogging thrust of the

cores

2A, 2B, and 2C is a sine wave. Even if the value is not set, the cogging thrust of the entire armature A can be reduced.

As described above, when the width W of the end teeth 4a of the

cores

2A and 2B is y / 2 + x, the single cogging thrust waveform of the

cores

As described above, the cylindrical linear motor M1 according to the first embodiment has a cylindrical shape in which the N pole and the S pole are alternately arranged in the axial direction, and the inner periphery of the field 6 A non-magnetic inner tube 9 disposed in the inner tube 9, a rod 11 movably inserted into the inner tube 9, an armature A attached to the rod 11, and an inner tube 9 provided in the rod 11.

Sliders

12 and 13 are provided which slide around the circumference and guide the movement of the armature A relative to the field 6.

In the cylindrical linear motor M1 configured as described above, a non-magnetic inner tube 9 is disposed between the field 6 and the armature A, and the

sliders

12 and 13 provided on the rod 11 include the inner tube 9. Since the movement of the armature A in the thrust direction is guided, the radial eccentricity with respect to the field 6 is suppressed. Therefore, according to the cylindrical linear motor M1 of the present invention, the eccentricity of the armature A with respect to the field 6 is prevented, and thrust can be generated stably. Further, in the cylindrical linear motor M1, the field 6 includes the non-magnetic inner tube 9 provided on the inner circumference of the

permanent magnets

10a and 10b, so that an electric machine is provided in the field 6 of the cylindrical linear motor M1. When inserting the child A, the armature A can be prevented from being attracted and stuck to the

permanent magnets

10a, 10b. Therefore, when the inner tube 9 is provided, the situation in which the armature A is attracted and stuck to the

permanent magnets

As described above, the armature A includes the two

cores

2A and 2B. However, the armature A may have a structure including only one core. The eccentricity of the child A can be suppressed. Further, one of the slider 12 and the slider 13 can be omitted, and the eccentricity of the armature A can be suppressed. Thus, when one of the

sliders

12 and 13 is omitted, a cylindrical linear motor is provided by providing a bearing in sliding contact with the outer periphery of the rod 11 on the inner periphery of the head cap 16 to suppress the eccentricity of the armature A with respect to the field 6. The thrust in M1 may be stabilized. If one of the

sliders

12 and 13 is omitted, if the armature A has two

cores

2A and 2B, the position where the spacer 14 is arranged in FIG. 1, that is, between the

cores

2A and 2B. A slider may be installed.

Further, in the cylindrical linear motor M1 of the present embodiment, since the

sliders

12 and 13 are provided on both sides of the armature A in the axial direction, the bending of the rod 11 can be suppressed, so that the field 6 of the armature A can be prevented. Eccentricity can be effectively suppressed. When the

sliders

12 and 13 are adjacent to the armature A, the effect of suppressing eccentricity becomes higher.

Since the

sliders

12 and 13 in the cylindrical linear motor M1 of the present embodiment are provided with lead in

chamfers

12c and 13c on the outer circumferences at both ends in the axial direction, moment and lateral force are applied to the rod 11 from the outside. Thus, even if the

sliders

12 and 13 are inclined with respect to the inner tube 9, it is possible to prevent the

sliders

12 and 13 from biting the inner peripheral surface of the inner tube 9 and roughening the inner peripheral surface of the inner tube 9. Therefore, the cylindrical linear motor M1 of the present embodiment can be extended and contracted smoothly over a long period of time.

Further, in the present embodiment, pins (rotation restricting portions) 24 and 25 for restricting relative rotation around the rod 11 between the

sliders

12 and 13 and the armature A, and the rod 11 around the spacer 14 and the

cores

2A and 2B. And the pins (spacer rotation restricting portions) 26 and 27 are provided. In the cylindrical linear motor M1 configured as described above, the relative rotation of the

sliders

12 and 13 and the spacer 14 and the

cores

2A and 2B around the rod 11 is restricted, so that the windings mounted in the slots 18 of the

cores

2A and 2B are restricted. It is possible to prevent a load such as a tension from being applied to the connecting wire 5a and the lead wire 5b connecting the wire 5 and the cable C. Therefore, in the cylindrical linear motor M1 configured in this way, it is possible to prevent occurrence of a situation in which the disconnection of the connecting wire 5a and the lead wire 5b is prevented and the coil 5 cannot be energized. When the armature A includes three

cores

2A, 2B, and 2C, and the spacers 14A and 14B are provided between the

cores

2A and 2B and between the cores 2B and 2C, respectively, the spacers 14A and 14B and the

cores

2A, 2B, What is necessary is just to protect the crossover 5a and the leader line 5b by providing the spacer rotation control part which controls mutual relative rotation with 2C.

In the present embodiment, the armature A includes the two

cores

2A and 2B, and the spacer 14 is provided between the

cores

2A and 2B, so that the connecting wire 5a and the lead wire 5b are protected. A spacer rotation restricting portion for restricting the relative rotation of the spacer 14 and the

cores

2A and 2B is provided. On the other hand, when the armature A has only a single core and no spacer is provided, if only the rotation restricting portion that restricts the relative rotation of the slider and the armature A is provided, the connecting wire 5a and the lead wire 5b are provided. Can be protected. Further, in the present embodiment, the windings 5 of each phase are connected not on the cable C side but on the right side of the slider 13 in FIG. 1, and the through-hole 13b is provided in the slider 13 so that the U phase and V phase are provided. The W-phase connecting wire 5a is drawn through the through hole 13b and connected to the outside. Therefore, the relative rotation between the slider 13 and the armature A is restricted. However, when the connecting wire 5a is connected to the cable C on the left side in FIG. 1 of the slider 12, the connecting wire 5a does not cross the slider 13. Therefore, the rotation restricting portion that restricts the relative rotation between the slider 13 and the armature A can be eliminated.

The cylindrical linear motor M1 of the present embodiment is cylindrical and has a field 6 in which N poles and S poles are alternately arranged in the axial direction, and an inner periphery of the field 6. A nonmagnetic inner tube 9 having a notch 9 a provided along the axial direction, a rod 11 movably inserted into the inner tube 9, an armature A attached to the rod 11, and the rod 11 And a regulating member 28 that is inserted into the notch 9a and regulates the rotation of the armature A around the rod with respect to the field 6.

The cylindrical linear motor M1 thus configured prevents the armature A, which is a mover, from rotating in the circumferential direction with respect to the field 6, which is a stator, so that even if the armature A is driven, The cable C connecting the winding 5 in the armature A is not twisted, and the cable C can be prevented from being disconnected. Therefore, according to the cylindrical linear motor M1 of the present invention, disconnection can be prevented even when the armature A side is used as a mover, and thrust can be stably generated over a long period of time.

In addition, the regulating member 28 may be attached to the slider 12, or when the armature A includes a plurality of

cores

2A and 2B and the spacer 14 is provided between the

cores

2A and 2B as in the present embodiment, the spacer 14 may be provided with a regulating member 28.

Note that, as in the cylindrical linear motor M3 shown in FIG. 10, a notch 9a may be provided in the middle of the inner tube 9, and the regulating member 29 may be screwed to the spacer 14. More specifically, as shown in FIG. 11, the inner tube 9 includes a notch 9a formed along the axial direction, and the regulating member 29 is inserted into the notch 9a. Thus, when the

sliders

12 and 13 are slidably contacted with the inner periphery of the inner tube 9 and the overall length and stroke range of the armature A are optimized, the notch 9a is not in the range where the

sliders

12 and 13 face each other. It can be installed in. Therefore, deterioration of the wear rings 12a and 13a of the

sliders

12 and 13 can be suppressed. When the notch 9a is provided in the middle of the inner tube 9 so that the notch 9a does not open at the end of the inner tube 9, the inner tube 9 is inserted after the armature A is inserted into the inner tube 9. The restricting member 29 may be screwed into the spacer 14 from the outside. In this case, the spacer 14 is provided with a hole that opens in the radial direction from the outer periphery, and a pin and an elastic body that urges the pin to protrude from the hole are inserted into the hole. You may comprise a control member. In this way, when the armature A, the regulating member and the rod 11 are assembled and inserted into the inner tube 9 up to a position facing the notch 9a, the pin projects into the notch 9a and the field of the armature A 6 is restricted.

Further, in the cylindrical linear motor M1 of the present embodiment, the

sliders

12 and 13 are provided on both sides in the axial direction of the armature A, and the spacer 14 is provided between the

cores

2A and 2B. As described above, when the armature A includes the plurality of

cores

2A and 2B, if the spacer 14 is provided between the

cores

2A and 2B, an excessive external force in the radial direction acts on the rod 11 and the rod 11 Even if it bends, it contacts the inner tube 9 prior to the

cores

2A and 2B. Therefore, according to the cylindrical linear motor M1 configured in this manner, the armature A can be protected by preventing the

cores

2A and 2B from interfering with the inner tube 9.

The cylindrical linear motor M1 according to the present embodiment includes a cylindrical yoke 3 and a plurality of

teeth

4a and 4b that are annular and are provided on the outer periphery of the yoke 3 with an interval in the axial direction. An armature A having a plurality of

cores

2A and 2B arranged side by side in the axial direction, and a winding 5 mounted in a slot 18 between the

teeth

4a and 4b of each

core

2A and 2B; A child A is inserted inward in the axial direction so as to be movable, and includes a field 6 in which N poles and S poles are alternately arranged in the axial direction, and is arranged at both ends with respect to the

cores

2A and 2B. Each tooth is a terminal tooth 4a, a tooth other than the terminal tooth 4a is an intermediate tooth 4b, the width of the outer peripheral end of the terminal tooth 4a is W, the width of the outer peripheral end of the intermediate tooth 4b is y, and x is a positive value. , The width W of the outer peripheral edge of the end teeth 4a is W = y / 2 And x, adjacent core 2A, the interval K of 2B Doko is set based on the value of x. In the cylindrical linear motor M1 configured in this way, the width W of the outer peripheral end of the end tooth 4a is set to a width that can reduce the cogging thrust, and the overall cogging thrust of the armature A is reduced. , 2B is not fixed to an integral multiple of the magnetic pole pitch P. As described above, since the axial length condition with respect to the magnetic pole pitch of the

cores

2A and 2B is not fixed, such as 5 times the magnetic pole pitch, the design freedom of the armature A is improved. Therefore, according to the cylindrical linear motor M1 of the present embodiment, the cogging thrust can be reduced while improving the design freedom. This also applies to the cylindrical linear motor M2 having three

cores

2A, 2B, and 2C. According to the cylindrical linear motor M2 of the present invention, cogging is achieved while improving the degree of freedom in design. Thrust can be reduced.

When the number of

cores

2A and 2B is two and the positions of the

cores

2A and 2B are in the range from 0 degrees to 360 degrees, the single cogging thrust waveform of the

cores

2A and 2B is a sine wave for two cycles. , Z is (1 + 2n) P / 2, the entire cogging thrust of the armature A can be minimized. In addition, the number of

cores

2A and 2B is two, and the

core

2A and 2B position is in the range from 0 degrees to 360 degrees, and the cogging thrust waveform of the

cores

2A and 2B is a sine wave for four cycles. In some cases, if z is (1 + 2n) P / 2, the entire cogging thrust of the armature A can be minimized. Therefore, when the number of

cores

2A and 2B is 2, and the interval K is K = z−2x, if the magnetic pole pitch of the field 6 is P and n is an integer greater than or equal to 0, the value z is the value x (1 + 2n) P / 2 or (1 + 2n) P / 4.

The number of

cores

2A, 2B, and 2C is three, and the

cores

2A, 2B, and 2C have a single cogging thrust waveform in the range from 0 degrees to 360 degrees. In the case of a sine wave for a period, if the value z is (1 + 3n) P / 3, the entire cogging thrust of the armature A can be minimized. When the number of

cores

2A, 2B, and 2C is three and the positions of the

cores

2A, 2B, and 2C are in the range of 0 degrees to 360 degrees, the single cogging thrust waveform of the

cores

2A, 2B, and 2C is for four cycles. If the value z is (1 + 3n) P / 6, the entire cogging thrust of the armature A can be minimized. Therefore, when the number of

cores

2A, 2B, 2C is 3, and the interval K is K = z-2x, if the magnetic pole pitch of the field 6 is P and n is an integer greater than or equal to 0, the value z is Based on the value x, it may be set to either (1 + 3n) P / 3 or (1 + 3n) P / 6.

Further, when the value x is set so that the waveform of the cogging thrust for the axial movement of the

cores

2A, 2B, and 2C with respect to the field 6 is a sine wave, the cogging thrusts of the

cores

2A, 2B, and 2C are effectively canceled with each other. Therefore, the cogging thrust of the cylindrical linear motors M1 and M2 can be minimized.

Further, when the width W of the outer peripheral end of the end tooth 4a is set to satisfy y / 2 + 0.01y ≦ W ≦ y / 2 + S, cogging is not caused without causing an unnecessary increase in mass of the

cores

2A, 2B, and 2C. Thrust can be reduced. And since the unnecessary mass increase of

core

2A, 2B, 2C is not caused, the mass thrust density of cylindrical linear motor M1 improves. Here, the mass thrust density is a numerical value obtained by dividing the maximum thrust of the cylindrical linear motor M1 having the above-described configuration by the mass, and the thrust does not increase even if the mass of the end teeth 4a increases. The mass thrust density is improved by reducing the mass of 4a. Therefore, according to the cylindrical linear motor M1 configured in this way, the thrust per mass is increased, so that a small and large thrust can be obtained.

Further, in the cylindrical linear motor M1 of the present embodiment, the intermediate teeth 4b are formed in an isosceles trapezoidal shape in which the width y of the outer peripheral end is narrower than the width yi of the inner peripheral end, and the end teeth 4a are the intermediate teeth. The side surface on the side has the same shape as the side surface of the intermediate teeth 4b, and the side surface on the anti-intermediate teeth side has a trapezoidal shape with a surface orthogonal to the axis J of the

cores

2A and 2B.

If the shape of the end teeth 4a is trapezoidal as described above, the axial width Wi of the inner peripheral end is larger than the axial width W of the outer peripheral end of the end teeth 4a as shown in FIG. Is big. When comparing the shape of the end tooth 4a as described above and the case where the axial width W of the outer peripheral end is the same and the end tooth 4a has a rectangular cross section, the end tooth 4a has a trapezoidal cross section. This increases the cross-sectional area of the magnetic path at the inner peripheral end. When the shape of the intermediate teeth 4b is set as described above, the axial width yi at the inner peripheral end is larger than the axial width y at the outer peripheral end of the intermediate teeth 4b as shown in FIG. A comparison between the case where the shape of the intermediate teeth 4b is the isosceles trapezoidal shape as described above and the case where the cross-section of the intermediate teeth 4b is rectangular with the same axial width y at the outer peripheral end is as follows. When the cross section is an isosceles trapezoid, the magnetic path cross-sectional area at the inner peripheral end becomes larger. Therefore, in the cylindrical linear motor M1 configured in this way, it becomes easy to secure a large magnetic path cross-sectional area, magnetic saturation when the winding 5 is energized can be suppressed, and a larger magnetic field can be generated, resulting in a larger thrust. Can be generated. In order to improve thrust, the cross-sectional shapes of the end teeth 4a and the intermediate teeth 4b are preferably trapezoidal. However, since there is no effect on the reduction of cogging thrust, the cross-sectional shapes of the end teeth 4a and the intermediate teeth 4b are rectangular. Alternatively, other shapes may be used.

According to the inventors' research, when the internal angle θ formed by the side surface and the orthogonal surface O in the cross section of the end tooth 4a and the intermediate tooth 4b is in the range of 6 degrees to 12 degrees, a good mass thrust density can be obtained. I understood. From the above, when the cross section of the end teeth 4a and the intermediate teeth 4b is trapezoidal, the thrust per mass of the cylindrical linear motor M1 becomes large when the internal angle θ is an angle in the range of 6 degrees to 12 degrees. A big thrust can be obtained.

Further, like the cylindrical linear motor M4 shown in FIG. 12, the

cores

2A and 2B are provided on the core body 21 on which the yoke 3, the end teeth 4a and the intermediate teeth 4b are provided, and on both ends of the core body 21, respectively. You may comprise by the

annular plates

22 and 22 mounted | worn so that attachment or detachment is possible. The

annular plates

22 and 22 have the same axial width and are made of the same material as that of the core body 21, and function as a part of the end teeth 4a when mounted on both ends of the core body 21, respectively. The function of adjusting the axial width W at the outer peripheral end of the end tooth 4a is exhibited. That is, the annular plate 22 is also responsible for adjusting the cogging thrust reduction. If the effect of reducing the cogging thrust is small with only the core body 21 due to the dimensional tolerance of the

cores

2A and 2B or the end teeth 4a, the effect of reducing the cogging thrust can be improved by mounting the

annular plates

22 and 22. Alternatively, annular plates 22 having different widths may be prepared, and the annular plate 22 having the optimum width may be selected and mounted on the core body 21, or a plurality of thin annular plates may be stacked on the core body 21. You may make it wear. When the annular plate 22 is attached to the core body 21, for example, a screw hole is provided in the core body 21 and a hole is provided in the annular plate 22, and the annular plate 22 is fixed to the core body 21 using a screw. Alternatively, other fixing methods may be adopted.

<Second Embodiment>
Next, the cylindrical linear motor M5 in the second embodiment will be described. As shown in FIG. 13, the cylindrical linear motor M5 of the second embodiment has a cylindrical shape and a field 36 in which N poles and S poles are alternately arranged in the axial direction. A non-magnetic inner tube 39 disposed on the inner periphery, a cylindrical rod 41 movably inserted into the inner tube 39, an armature A1 attached to the rod 41, and the rod 41 are provided.

Sliders

51b and 55 that slide in contact with the inner periphery of the inner tube 39 to guide the movement of the armature A1 relative to the field 36, the outer tube 37, the outer tube 37 provided on the outer periphery of the field magnet 36, and the outer tube 37 An annular head cap 45 that is attached to the opening end and into which the rod 41 is inserted is provided.

Hereinafter, each part of the cylindrical linear motor M5 will be described in detail. The armature A1 includes a core 33 and a winding 35. The core 33 includes a cylindrical core body 33a and a plurality of teeth 33b that are annular and are provided on the outer periphery of the core body 33a at intervals in the axial direction.

As shown in FIG. 13, the core 33 has the same shape as the core 2A of the cylindrical linear motor M1 of the first embodiment, and has a cylindrical shape. Ten teeth 33b are provided side by side, and a slot 34 is formed between the

teeth

33b and 33b. The windings 35 attached to the slots 34 are U-phase, V-phase, and W-phase three-phase windings, and the winding 5 is attached in the same manner as the slot 18 of the first embodiment. Are installed in the slot 34 in the same order as described above.

The armature A1 configured in this way is mounted on the outer periphery of a rod 41 formed of a nonmagnetic material that is an output shaft. The rod 41 includes a cylindrical first rod 50 and a second rod 51 that is cylindrical and has a core 33 attached to the outer periphery thereof and screwed to the inner periphery of the first rod 50. A stroke sensor L is accommodated in the rod 41.

The first rod 50 is cylindrical and has a rod body 52 having

screw portions

52a and 52b on the left outer periphery in FIG. 13 and the right inner periphery in FIG. 13, and a bracket 53a for attaching the cylindrical linear motor M5 to the device. The rod main body 52 is provided with an end cap 53 that is screwed into a screw portion 52 a at the left end in FIG. 13 and closes the left end of the rod main body 52. An annular slider 55 is fitted on the outer periphery of the right end of the rod body 52 in FIG. A flange 55 a is provided on the inner periphery of the right end of the slider 55. The inner diameter of the flange 55a is equal to or larger than the inner diameter of the rod main body 52 and smaller than the outer diameter of the rod main body 52. Abut. Further, a cylindrical cover 47 that covers the outer periphery of the rod 41 by being fitted to a flange 48 provided on the left end side of the rod 41 in FIG. 13 and the slider 55 is provided, and between the cover 47 and the rod 41. An annular space is formed in.

The second rod 51 includes a cylindrical core holding cylinder 51a on which the core 33 is mounted on the outer periphery, and an annular slider 51b provided on the outer periphery of the tip which is the right end in FIG. 13 of the core holding cylinder 51a. Further, a screw portion 51c is provided on the outer periphery of the base end that is the left end in FIG. 13 of the core holding cylinder 51a, and the inner diameter of the core holding cylinder 51a is larger in the inner diameter than other parts on the inner periphery of the base end side A large diameter portion 51d is provided. Then, when the screw portion 51c is screwed into the screw portion 52b while the proximal end of the core holding cylinder 51a is inserted into the inner periphery of the rod body 52 of the first rod 50 at the right end in FIG. The rod 51 is connected.

Thus, the rod 41 includes the first rod 50 and the second rod 51, and the sensor body 60 in the stroke sensor L is accommodated in the first rod 50.

The core 33 is fitted and attached to the outer periphery of the core holding cylinder 51a of the second rod 51. Since the outer diameter of the core holding cylinder 51a is smaller than the outer diameter of the rod body 52 in the first rod 50, the second rod 51 with the armature A1 attached to the first rod 50 with the slider 55 attached. When connected as described above, the armature A1 and the slider 55 are sandwiched and fixed between the right end of the first rod 50 in FIG. 13 and the slider 51b of the second rod 51. When the armature A1 is mounted on the rod 41 in this way, the core 33 is fixed to the rod 41 in such a manner as to be sandwiched between the slider 51b and the slider 55.

On the other hand, in the present embodiment, the stator S includes an outer tube 37 formed of a cylindrical nonmagnetic material, and a back yoke 38 formed of a cylindrical soft magnetic material inserted into the outer tube 37. The field magnet 36 includes an annular main magnetic pole permanent magnet 40 a and an annular sub magnetic pole permanent magnet 40 b that are alternately stacked in the axial direction in the back yoke 38. A non-magnetic inner tube 39 is provided on the inner periphery of the

permanent magnets

40a and 40b of the field magnet 36. That is, the

permanent magnets

40 a and 40 b are accommodated in the annular gap between the back yoke 38 and the inner tube 39. Similarly to the cylindrical linear motor M1 of the first embodiment, the field magnet 36 is composed of a main magnetic pole permanent magnet 40a and an annular sub magnetic pole permanent magnet 40b arranged in a Halbach array. A magnetic field in which S poles and N poles appear alternately in the axial direction of the circumference is applied. In addition, even in the cylindrical linear motor M5 of the present embodiment, the axial length of the permanent magnet 40a of the main magnetic pole is set to the permanent magnet 40b of the sub magnetic pole as in the cylindrical linear motor M1 of the first embodiment. The axial length of the

permanent magnets

40a and 40b can be arbitrarily changed. However, the axial length of the

permanent magnets

40a and 40b can be arbitrarily changed. Further, the field magnet 36 may be composed of permanent magnets arranged in an arrangement other than the Halbach arrangement.

Further, when the back yoke 38 is provided, a magnetic path with a low magnetic resistance can be secured, so that an increase in the magnetic resistance due to the shortening of the axial length of the permanent magnet 40b of the sub magnetic pole is suppressed, and the cylindrical linear motor M5 The thrust can be greatly improved as in the cylindrical linear motor M1 of the first embodiment.

In the present embodiment, the axial length of the back yoke 38 is longer than the axial length of the field magnet 36, and the field magnet 36 is always provided even if there is a dimensional error in the axial length of the

permanent magnets

40a and 40b. Consideration is made so as to oppose the back yoke 38, and leakage of magnetic flux of the permanent magnet at the end of the field 36 is prevented to prevent a decrease in thrust of the cylindrical linear motor M5.

Further, the left ends of the outer tube 37, the back yoke 38 and the inner tube 39 in FIG. 13 are closed by an annular head cap 45 into which the rod 41 is inserted on the inner periphery. The outer tube 37 is reduced in diameter on the right end side in FIG. 13 and is provided with a bottom portion 37a. The outer tube 37 includes a bracket 37b at the right end of the bottom portion 37a that allows the cylindrical linear motor M5 to be attached to a device.

The head cap 45 is annular and has a rod 41 inserted through the inner periphery thereof. The head cap 45 is attached to the outer tube 37 by being screwed to the inner periphery of the open end of the outer tube 37 at the left end in FIG. For mounting the head cap 45 to the outer tube 37, for example, a mounting method other than screw fastening such as welding or pipe end crimping may be employed. Further, as shown in FIG. 13, the head cap 45 and the inner tube 39 are made of a non-magnetic material and are integrally molded, and the inner tube 39 projects rightward from the right end of the head cap 45 in FIG. . A field 36 is mounted on the outer periphery of the inner tube 39 so as not to move in the axial direction. Specifically, an annular spacer 65, a field magnet 36, and an annular stopper 66 are sequentially fitted from the left in FIG. 13 to the outer periphery of the inner tube 39, and when the head cap 45 is screwed to the outer tube 37, The spacer 65, the field magnet 36, and the stopper 66 are sandwiched between the head cap 45 and the bottom portion 37 a of the outer tube 37, and the field magnet 36 is fixed to the outer periphery of the inner tube 39. Note that the back yoke 38 attached to the outer periphery of the field magnet 36 is restrained by the field magnet 36 by the magnetic force of the field magnet 36, and therefore does not move within the outer tube 37.

In addition, an annular seal member 58 is provided on the inner periphery of the head cap 45 so as to be in sliding contact with the outer periphery of the cover 47 covering the outer periphery of the first rod 50, so that dust, water, etc. into the cylindrical linear motor M5 are provided. Intrusion is prevented.

Then, the rod 41 with the armature A1 attached is inserted into the inner tube 39 so as to be movable in the axial direction, and the

sliders

51b and 55 are slidably contacted with the inner periphery of the inner tube 39, so that the axial direction of the armature A1 is increased. Movement is guided.

The inner tube 39 forms a gap between the outer periphery of the core 33 and the inner periphery of each

permanent magnet

40a, 40b, and plays a role of guiding the axial movement of the core 33 in cooperation with the

sliders

51b, 55. Yes. In the present embodiment, the electric element A1 includes only a single core 33. However, in the case where the electric element A1 has a plurality of cores 33, not only the axial ends of the electric element A1 but also the cores 33, A slider that slides on the inner periphery of the inner tube 39 may also be provided between 33.

permanent magnet

sliders

51b, 55. Yes. Although not shown, chamfered and lead in chamfers are provided on the outer circumferences of both ends in the axial direction of the

sliders

51 b and 55, and the

sliders

51 b and 55 are provided even if the rod 41 is inclined with respect to the inner tube 39. However, care is taken so that the inner peripheral surface of the inner tube 39 is not scratched.

Furthermore, a guide rod 46 is attached to the inner periphery of the bottom 37a of the outer tube 37. The guide rod 46 includes a base end portion 46a that is fixed to the inner periphery of the bottom portion 37a, and a guide portion 46b that extends from the base end portion 46a toward the rod 41 and is slidably inserted into the rod 41. . More specifically, the guide portion 46b of the guide rod 46 is slidably inserted on the distal end side with respect to the inner diameter large diameter portion 51d of the second rod 51, so that the rod is always maintained even when the cylindrical linear motor M5 expands and contracts. 41 is in sliding contact with the inner circumference.

As described above, the

sliders

51 b and 55 are in sliding contact with the inner periphery of the inner tube 39, and the guide rod 46 is in sliding contact with the inner periphery of the rod 41. On the other hand, it can move smoothly in the axial direction without being eccentric.

Subsequently, the stroke sensor L is a linear variable differential transformer in the present embodiment, and although not shown in detail, a cylindrical sensor body 60 containing a primary coil and two secondary coils, A probe 62 is inserted into the sensor main body 60 so as to be movable in the axial direction, and has a sensor core 61 as a detection element at the tip. The linear variable differential transformer detects the position of the sensor core 61 from the difference between the induced voltages of the two secondary coils that are induced when an AC voltage is applied to the primary coil.

When the sensor body 60 is inserted into the first rod 50 in advance, the slider 55 is fitted to the end of the first rod 50, and the second rod 51 is screwed to the first rod 50, the sensor body 60 is The second rod 51 is clamped by a step formed at the right end of the inner diameter large diameter portion 51 d and the end cap 53 of the first rod 50 and fixed in the first rod 50. Thus, the sensor main body 60 is accommodated in the first rod 50 where the armature A1 is not mounted on the outer periphery, and is accommodated in a range that does not face the armature A1 in the radial direction of the rod 41.

Further, the probe 62 in the stroke sensor L is rod-shaped and attached to the tip of the guide portion 46b in the guide rod 46. Therefore, the sensor core 61 as the detection element is fixedly connected to the field magnet 36 via the probe 62, the guide rod 46 and the outer tube 7. As described above, the probe 62 includes the sensor core 61 at the distal end, and the distal end side is inserted into the sensor main body 60. Therefore, as the armature A1 moves in the axial direction relative to the field magnet 36, the probe 62 moves relative to the sensor main body 60 in the axial direction, and the sensor core 61 moves in the sensor main body 60. .

Since the guide rod 46 that holds the probe 62 is slidably inserted into the rod 41 that accommodates the sensor main body 60, eccentricity of the sensor core 61 in the radial direction with respect to the sensor main body 60 is prevented. Note that the energization wiring to the primary coil of the sensor body 60 and the wiring 60a connected to the secondary coil are drawn out from the hole 53b provided in the end cap 53 and connected to a controller (not shown).

The cable C connected to the winding 35 is accommodated in a space between the rod 41 and the cylindrical cover 47 covering the outer periphery of the rod 41, and is drawn out of the cylindrical linear motor M5. It is connected to a drive circuit (not shown) controlled by the controller. Therefore, the winding 35 can be energized from an external drive circuit.

The controller (not shown) senses the electrical angle of the winding 35 with respect to the field 36 with the stroke sensor L, switches the energization phase based on the electrical angle, and controls the current amount of each winding 35 by PWM control. Then, the thrust in the cylindrical linear motor M5 and the moving direction of the armature 2 are controlled. In addition, the control method in the above-mentioned controller is an example, and is not restricted to this. Thus, in the cylindrical linear motor M5 of the present embodiment, the armature A1 is a mover and the field 36 behaves as the stator S. In addition, when an external force that relatively displaces the armature A1 and the field magnet 36 in the axial direction acts, the thrust that suppresses the relative displacement by energizing the winding 35 or the induced electromotive force generated in the winding 35. Can be generated to cause the cylindrical linear motor M5 to dampen the vibration and movement of the device due to the external force, and energy regeneration that generates electric power from the external force is also possible.

As described above, the cylindrical linear motor M5 according to the second embodiment has a cylindrical field 36 in which N poles and S poles are alternately arranged in the axial direction, and the inner periphery of the field magnet 36. A non-magnetic inner tube 39, a rod 41 movably inserted into the inner tube 39, an armature A1 attached to the rod 41, and an inner tube 39 provided on the rod 41.

Sliders

51b and 55 are provided which slide around the circumference and guide the movement of the armature A1 relative to the field 36. In the cylindrical linear motor M5 configured as described above, a non-magnetic inner tube 39 is disposed between the field magnet 36 and the armature A1, and

sliders

51b and 55 provided on the rod 41 are connected to the inner tube 39. Since the armature A1 is guided to move in the thrust direction, radial eccentricity with respect to the field 36 is suppressed. Therefore, the cylindrical linear motor M5 of the second embodiment can prevent the eccentricity of the armature A1 with respect to the field magnet 36 and generate a stable thrust, similarly to the cylindrical linear motor M1 of the first embodiment. it can. The cylindrical linear motor M5 includes a non-magnetic inner tube 39 provided on the inner periphery of the

permanent magnets

40a and 40b. Therefore, when the armature A1 is inserted into the field magnet 36, the armature A1 is inserted. Can be prevented from being attracted and stuck to the

permanent magnets

40a and 40b, and the assembly work can be facilitated. Further, in the cylindrical linear motor M5 of the present embodiment, since the

sliders

51b and 55 are provided on both sides in the axial direction of the armature A1, the bending of the rod 41 can be suppressed, so that the field 36 of the armature A1 is prevented. Eccentricity can be effectively suppressed.

Furthermore, the cylindrical linear motor M5 according to the second embodiment has an outer tube 37 provided on the outer periphery of the field magnet 36, and an annular shape that is attached to the opening end of the outer tube 37 and the rod 41 is inserted into the inner periphery. The head cap 45 is provided, and the inner tube 39 is provided integrally with the head cap 45. In the cylindrical linear motor M5 configured as described above, the inner tube 39 that guides the axial movement of the armature A1 to prevent the eccentricity of the armature A1 with respect to the field 36 is integrated with the head cap 45. Therefore, the inner tube 39 and the head cap 45 are hardly distorted, and the

sliders

51b and 55 can smoothly slide on the inner periphery of the inner tube 39, and can smoothly expand and contract.

Further, the field magnet 36 in the cylindrical linear motor M5 according to the second embodiment is mounted on the outer periphery of the inner tube 39 while being restricted from moving in the axial direction. In the cylindrical linear motor M5 configured as described above, the axial load received by the field 36 from the armature A1 is always transmitted to the outer tube 37 through the head cap 45. As described above, since the load path (load transmission path) of the cylindrical linear motor M5 is only one passing through the head cap 45, the strength design is facilitated.

Furthermore, the rod 41 in the cylindrical linear motor M5 of the second embodiment is cylindrical and includes a guide rod 46 that is connected to the outer tube 37 and is slidably inserted into the rod 41. . According to the cylindrical linear motor M5 configured as described above, the inner tube 39 and the

sliders

51b and 55 guide the movement of the rod 41 relative to the field 36, and the guide rod 46 and the rod 41 can Since the movement of the rod 41 with respect to the field 36 is guided also from the bottom 37a side of the tube 37, the eccentricity of the armature A1 with respect to the field 36 is more effectively prevented.

Further, the

sliders

51b and 55 in the cylindrical linear motor M5 of the second embodiment have lead in chamfers on the outer circumferences at both ends in the axial direction, and the

sliders

51b and 55 are arranged on the inner circumferential surface of the inner tube 39. Since it is possible to prevent galling, the cylindrical linear motor M5 of the present embodiment can smoothly extend and contract over a long period of time.

The cylindrical linear motor M5 of the second embodiment includes a stroke sensor L that is inserted into the rod 41 and detects the position of the rod 41 with respect to the field magnet 36. The stroke sensor L is connected to the field magnet 36. The sensor core 61 is fixed to the rod 41 and inserted into the rod 41, and the sensor body 60 is housed in the rod 41 and detects the position of the sensor core 61. In the cylindrical linear motor M5 configured as described above, the stroke sensor L is accommodated in the rod 41 having the armature A1 on the outer periphery. The stroke sensor L is not directly exposed. Therefore, the stroke sensor L is protected from the heat of the armature A1 and is not exposed to the magnetic field of the field 36, so that the detected position of the armature A1 can be accurately detected. As described above, according to the cylindrical linear motor M5 of the present embodiment, the reliability of the detected position of the armature A1 can be improved.

Furthermore, in the cylindrical linear motor M5 of the present embodiment, the sensor body 60 is accommodated in a range that does not face the armature A1 in the rod 41 in the radial direction. According to the cylindrical linear motor M5 configured in this way, the sensor body 60 and the armature A1 do not overlap in the radial direction during the stroke of the cylindrical linear motor M5. It becomes difficult to be influenced, and the reliability of the detected position of the armature 2 can be improved more effectively.

The cylindrical linear motor M5 of the present embodiment includes a guide rod 46 that is connected to the field magnet 36 and is slidably inserted into the rod 41, and the sensor core 61 is attached to the guide rod 46. Yes. According to the cylindrical linear motor M5 configured as described above, the sensor core 61 that moves relative to the sensor body 60 is mounted on the guide rod 46 that guides the movement of the rod 41 in the axial direction. The eccentricity of the sensor core 61 with respect to the main body 60 is prevented, and the stroke sensor L can accurately detect the position of the armature A1.

Furthermore, the rod 41 in the cylindrical linear motor M5 of the present embodiment has a cylindrical first rod 50 and a cylindrical shape with the core 33 mounted on the outer periphery and screwed into the inner periphery of the first rod 50. The sensor body 60 is sandwiched between the first rod 50 and the second rod 51 and fixed in the rod 41. According to the cylindrical linear motor M5 configured in this way, it is very easy to fix the stroke sensor L in the rod 41 and to attach the armature A1 to the rod 41, so that a good assembling property is obtained. It is done.

The stroke sensor L may be a magnetostrictive stroke sensor instead of the linear variable differential transformer, or may be a linear potentiometer. In any case, the stroke sensor L is fixed to the field magnet 36. What is necessary is just to make it detect with the sensor main body fixed to the rod 41 side.

The preferred embodiments of the present invention have been described in detail above, but modifications, changes, and changes can be made without departing from the scope of the claims.

This application claims priority based on Japanese Patent Application No. 2018-079340 filed with the Japan Patent Office on April 17, 2018, the entire contents of which are incorporated herein by reference.

Claims

A cylindrical linear motor,
A cylindrical magnetic field in which N and S poles are alternately arranged in the axial direction;
A non-magnetic inner tube disposed on the inner periphery of the field;
A rod movably inserted into the inner tube;
An armature attached to the rod;
A cylindrical linear motor comprising: a slider provided on the rod and slidably contacting the inner periphery of the inner tube to guide the movement of the armature relative to the field.
The cylindrical linear motor according to claim 1,
A cylindrical linear motor comprising a rotation restricting portion that restricts relative rotation of the slider and the armature around the rod.
The cylindrical linear motor according to claim 1,
The said slider is each provided in the both sides of the axial direction of the said armature with respect to the said rod. Cylindrical linear motor.
The cylindrical linear motor according to claim 1,
The armature has a plurality of cores having a plurality of slots that are cylindrical and have windings mounted on the outer periphery;
A cylindrical linear motor including a spacer provided on the rod and disposed between the cores.
The cylindrical linear motor according to claim 4,
A cylindrical linear motor comprising a spacer rotation restricting portion that restricts relative rotation of the spacer and each core around the rod.
The cylindrical linear motor according to claim 1,
An outer tube provided on the outer periphery of the field;
An annular head cap that is attached to the open end of the outer tube and through which the rod is inserted into the inner periphery;
The inner tube is provided integrally with the head cap. A cylindrical linear motor.
The cylindrical linear motor according to claim 6,
The field magnet is mounted on the outer periphery of the inner tube while being restricted from moving in the axial direction.
The cylindrical linear motor according to claim 6,
The rod is cylindrical,
A cylindrical linear motor comprising a guide rod connected to the outer tube and slidably inserted into the rod.
The cylindrical linear motor according to claim 1,
The said slider has a lead in chamfer on the outer periphery of the both ends of an axial direction.