WO2013069148A1

WO2013069148A1 - Cylindrical linear motor

Info

Publication number: WO2013069148A1
Application number: PCT/JP2011/076059
Authority: WO
Inventors: 陽介高石; 治之長谷川; 徹片江
Original assignee: 三菱電機株式会社
Priority date: 2011-11-11
Filing date: 2011-11-11
Publication date: 2013-05-16
Also published as: TW201320559A; JP5680216B2; JPWO2013069148A1; KR20140084318A; CN103947091A; TWI491147B; KR101635691B1

Abstract

This cylindrical linear motor is equipped with: an armature unit (10) which has a cylindrical frame (11), a cylindrical yoke (12) which is made of a magnetic body and fitted into the frame (11), multiple ring-shaped coils (13u, 13v, 13w) which are arranged in the axial direction inside the yoke (12), and bearings which are fixed to either end of the frame (11); a magnetic field unit (20) which is inserted into the armature unit (10), and is formed into a stepped shaft shape which comprises a large-diameter intermediate section where multiple permanent magnets (22) are arranged in the axial direction and small-diameter intermediate sections (24b) which extend from the large-diameter intermediate section in both directions in the axial direction and are inserted into the bearings; and a cylindrical or ring-shaped cushioning member (26) through which the small-diameter intermediate section (24b) is inserted, and which is positioned coaxially with the small-diameter intermediate section (24b) and fixed to the step part of the magnetic field unit (20) or to one end of the frame (11).

Description

Cylindrical linear motor

The present invention relates to a cylindrical linear motor.

The cylindrical linear motor includes an armature portion as a stator in which a plurality of U-phase, V-phase, and W-phase ring coils are arranged in an axial direction in a cylindrical yoke made of a magnetic material, and the armature A field part as a mover arranged in the axial direction with a plurality of permanent magnets arranged in a shaft direction through a plate-like spacer made of a magnetic material, with N poles and S poles facing each other, And a bearing portion such as a linear bush or a ball bush that is provided at both end portions of the armature portion and supports the shaft so as to be movable in the axial direction.

In the above cylindrical linear motor, when the power is cut off during the acceleration operation, when the control runs out of control or when the control command is wrong, the field part collides with the bearing part, and the armature part or field There is a risk of damage to the magnetic part. Further, when the cylindrical linear motor is used in a vertical position, when the power is turned off, the field part falls due to its own weight and collides with the bearing part. If this collision is repeated, frictional failure and fatigue failure occur, leading to damage to the cylindrical linear motor.

2. Description of the Related Art Conventionally, in an injection molding machine that performs an operation of injecting molten resin using a linear motor, a mold and a hollow portion that communicates with a gap of the mold are heated, and a resin raw material received in the hollow portion is heated. A barrel having a heating means for melting, a screw inserted into the hollow portion and driven to advance and retreat in the axial direction, and an output shaft connected to a rear end portion of the screw, and the molten resin is the hollow portion A movable part of a linear motor that moves the output shaft in the axial direction so as to be injected toward the gap of the mold, a mount part having a linear guide for supporting and guiding the movable part of the linear motor, and a stroke At the limit, the movable part of the linear motor is attached to two parts of the front and rear mounting parts to collide and absorbs the impact force caused by the collision of the movable part of the linear motor. A buffer member made of spring or urethane cushion to Gensa, with an injection molding machine is disclosed (for example, see Patent Document 1).

The linear motor includes a fixed portion and a movable portion, and the fixed portion includes a case that also serves as a yoke, a plurality of salient pole type iron cores that are attached to the upper and lower inner wall surfaces of the case in the axial direction, and the iron core The movable part consists of a winding wound around each, the movable part is composed of a yoke, a plurality of permanent magnets mounted on both sides of the yoke, and an output shaft that transmits the movement of the movable part in the axial direction to the outside. Two shock absorbers made of rubber and other elastic bodies that absorb the kinetic energy when the movable part hits are provided at two locations on the axial end face of the case. A linear motor in which members are arranged is disclosed (for example, see Patent Document 2).

JP 2002-355868 A Japanese Patent Application Laid-Open No. 07-232642 (3rd and 4th pages, FIG. 1)

However, according to the conventional techniques disclosed in Patent Documents 1 and 2, two buffer members are arranged at two locations on the upper and lower sides or on the left and right sides of the output shaft. Therefore, there is a problem that the number of parts is large. In addition, when the movable portion collides first with either of the two buffer members, there is a problem in that a bending force acts on the movable portion and the output shaft, and an unbalanced load is applied to the bearing that supports the output shaft. Further, since the buffer member is disposed outside the motor, there is a problem that the buffer member is severely deteriorated and the design property is impaired.

The present invention has been made in view of the above, and an object of the present invention is to obtain a cylindrical linear motor having a cushioning member having a small number of parts, low cost, high reliability, little deterioration, and good design. To do.

In order to solve the above-described problems and achieve the object, the present invention includes a cylindrical frame, a cylindrical yoke made of a magnetic material fitted in the frame, and an axial arrangement in the yoke. An armature portion having a plurality of ring-shaped coils and bearings fixed to both ends of the frame, and a large-diameter intermediate member inserted into the armature portion and having a plurality of permanent magnets arranged in the axial direction. And a small-diameter shaft portion extending in the axial direction from the large-diameter intermediate portion and inserted into the bearing, a field portion formed in a stepped shaft shape, and the small-diameter shaft portion being inserted And a cylindrical or ring-shaped cushioning member disposed coaxially with the small-diameter shaft portion and fixed to a stepped portion of the field magnet portion or an end portion of the frame.

A cylindrical linear motor according to the present invention includes a cylindrical or ring-shaped buffer member that is inserted in a small-diameter shaft portion and arranged coaxially with the small-diameter shaft portion, and is fixed to a step portion of a stepped shaft or an end portion of a frame. Since it is provided, the number of parts of the buffer member is small, and there is an effect that the reliability is low and the cost is high.

FIG. 1 is a longitudinal sectional view showing Embodiment 1 of a cylindrical linear motor according to the present invention. FIG. 2 is an enlarged view of part A in FIG. FIG. 3 is a longitudinal sectional view showing a state in which the mover of the cylindrical linear motor of Embodiment 1 has moved leftward. FIG. 4 is a partially enlarged longitudinal sectional view showing Embodiment 2 of the cylindrical linear motor according to the present invention. FIG. 5 is a longitudinal sectional view showing Embodiment 3 of the cylindrical linear motor according to the present invention. FIG. 6 is an enlarged view of a portion B in FIG. FIG. 7 is a partially enlarged longitudinal sectional view showing Embodiment 4 of the cylindrical linear motor according to the present invention. FIG. 8 is a partially enlarged longitudinal sectional view showing Embodiment 5 of the cylindrical linear motor according to the present invention. FIG. 9 is a partially enlarged longitudinal sectional view showing Embodiment 6 of the cylindrical linear motor according to the present invention. FIG. 10 is a partially enlarged longitudinal sectional view showing a deformed state of the cushioning material at the time of collision of the cylindrical linear motor according to the sixth embodiment. FIG. 11 is a partially enlarged longitudinal sectional view showing Embodiment 7 of the cylindrical linear motor according to the present invention. FIG. 12 is a partially enlarged longitudinal sectional view showing an eighth embodiment of the cylindrical linear motor according to the present invention.

Hereinafter, an embodiment of a cylindrical linear motor according to the present invention will be described in detail with reference to the drawings. Note that the present invention is not limited to the embodiments.

Embodiment 1 FIG.
FIG. 1 is a longitudinal sectional view showing a first embodiment of a cylindrical linear motor according to the present invention, FIG. 2 is an enlarged view of part A of FIG. 1, and FIG. 3 is a cylindrical shape of the first embodiment. It is a longitudinal cross-sectional view which shows the state which the mover of the linear motor moved to the left.

As shown in FIGS. 1 to 3, a cylindrical linear motor 91 according to the first embodiment includes a cylindrical armature portion 10 that serves as a stator, and the armature portion 10 is inserted coaxially with the armature portion 10. And a field portion 20 having an intermediate portion formed in a stepped shaft shape having a large diameter.

The armature portion 10 is a cylindrical frame 11 made of a non-magnetic material such as aluminum or resin, a cylindrical yoke 12 made of a magnetic metal fitted in the frame 11, and an axial arrangement in the yoke 12. A plurality of ring-shaped U-phase coils 13u, V-phase coils 13v, and W-phase coils 13w; and ring-shaped insulating plates 14 that insulate between the U, V, and W-

phase coils

13u, 13v, and 13w; A cylindrical bobbin 15 around which W-

phase coils

13u, 13v, and 13w are wound (the ring-shaped insulating plate 14 and the bobbin 15 may be integrally formed of resin), and a bearing fixed to both ends of the frame 11. A holder 16 and a bearing 17 such as a linear bush or a ball bush held by the bearing holder 16 are provided.

The field portion 20 is adjacent to a pipe 21 made of a nonmagnetic material such as stainless steel (SUS304) or aluminum that transmits magnetic flux, and a plurality of thick plate-like permanent magnets 22 arranged in the axial direction in the pipe 21. And a magnetic metal spacer 23 inserted between the matching permanent magnets 22. The permanent magnet 22 is disposed so that the N poles and the S poles face each other with the spacer 23 interposed therebetween.

The large diameter portion 24a of the stepped shaft 24 is fitted into both ends of the pipe 21, and the small diameter shaft portion 24b of the stepped shaft 24 extends from the pipe (large diameter intermediate portion) 21 to both sides in the axial direction. The field portion 20 as a mover is formed in a stepped shaft shape having a thick central portion as a whole by fitting the large diameter portion 24a of the stepped shaft 24 to both ends of the pipe 21. The small diameter shaft portion 24 b of the stepped shaft 24 is supported by the bearings 17 at both ends of the armature portion 10 so as to be capable of reciprocating in the axial direction.

One (left side in FIG. 1) of the stepped shaft 24 has a ring shape made of a non-magnetic material (aluminum, resin, etc.) at the root of the large diameter portion 24a of the small diameter shaft portion 24b (step portion of the field portion 20). The spring holder 25 is externally fitted. A spiral groove is provided on the outer peripheral portion of the spring holder 25, and a cylindrical or ring-shaped buffer in which the small diameter shaft portion 24b of the stepped shaft 24 is inserted into the spiral groove and is coaxially arranged with the small diameter shaft portion 24b. A coil spring 26 as a member is attached. Although not shown, the spring holder 25 and the coil spring 26 may be attached to the small diameter shaft portion 24b of the other stepped shaft 24 (the right side in FIG. 1).

The cylindrical linear motor 91 detects the position of the magnetic pole of the field part (movable element) 20 by a magnetic sensor (Hall element) provided in the armature part (stator) 10 or uses a linear encoder to detect the field. The moving position of the unit 20 is detected, and based on the detected position information, the energization to the U, V, and

W phase coils

13u, 13v, and 13w is switched, and the field unit 20 is moved along the armature unit 10 in the axial direction. Drive linearly.

If the field unit 20 runs out of control when the power is cut off during the acceleration operation of the cylindrical linear motor 91, the control is not performed, or the control command is wrong, as shown in FIG. The left end portion of the coil spring 26 attached to 20 collides with the right end surface of the bearing holder 16 of the armature portion 10, and the coil spring 26 is compressed to absorb the kinetic energy of the field portion 20 and alleviate the impact. . The wire diameter and the number of turns of the coil spring 26 are determined according to the kinetic energy of the field magnet portion 20.

In the cylindrical linear motor 91 according to the first embodiment, since one coil spring 26 is mounted on the step portion of the stepped shaft 24 coaxially with the small diameter shaft portion 24b, the number of parts is small and the coil spring 26 is axially symmetric. Therefore, no bending force acts on the small diameter shaft portion 24b.

Embodiment 2. FIG.
FIG. 4 is a partially enlarged longitudinal sectional view showing Embodiment 2 of the cylindrical linear motor according to the present invention. As shown in FIG. 4, the cylindrical linear motor 92 according to the second embodiment has a ring-shaped buffer member as a ring-shaped cushioning member on the base (step) on the large diameter portion 24 a side of the small diameter shaft portion 24 b of the stepped shaft 24. A soft rubber O-ring 26a is externally fitted.

Since the O-ring 26a is fixed to the root (step) of the small diameter shaft portion 24b of the stepped shaft 24 by its own tightening margin, no holders are required. Even if an O-ring 26a is used in place of the coil spring 26, the same effect as the coil spring 26 can be obtained and the buffer member can be manufactured at low cost.

Embodiment 3 FIG.
FIG. 5 is a longitudinal sectional view showing Embodiment 3 of the cylindrical linear motor according to the present invention, and FIG. 6 is an enlarged view of part B of FIG. As shown in FIGS. 5 and 6, in the cylindrical linear motor 93 of the third embodiment, a cylindrical spring holder 25 a is fitted in the small diameter hole 11 a at the end of the frame 11. An inner flange 25aa is provided at an end portion of the spring holder 25a, and an end portion of a coil spring 26 as a buffer member housed in the spring holder 25a is engaged with the inner flange 25aa. The small diameter shaft portion 24 b of the stepped shaft 24 protrudes to the outside through the coil spring 26.

When the field part 20 runs out of control, the side surface of the large diameter part 24a of the stepped shaft 24 collides with the right end face of the coil spring 26, and the coil spring 26 is compressed to absorb the kinetic energy of the field part 20 and apply an impact. ease. Thus, even if the coil spring 26 is attached to the end portion of the armature portion 10, the same effect as that provided on the field portion 20 side is obtained. If the coil spring 26 is attached to the armature part (stator) 10 side, the weight of the field part (mover) 20 does not increase, so that the drive characteristics of the field part 20 are not affected.

Embodiment 4 FIG.
FIG. 7 is a partially enlarged longitudinal sectional view showing Embodiment 4 of the cylindrical linear motor according to the present invention. As shown in FIG. 7, in the cylindrical linear motor 94 of the fourth embodiment, a cylindrical O-ring holder 25 b is fitted in the small diameter hole 11 a at the end of the frame 11. A large inner diameter portion 25ba is formed at the end of the O ring holder 25b, and an O ring 26b as a buffer member is engaged with the large inner diameter portion 25ba. The small diameter shaft portion 24b of the stepped shaft 24 protrudes outside through the O-ring 26b without contacting the O-ring 26b.

When the field part 20 runs away, the side surface of the large diameter part 24a of the stepped shaft 24 collides with the right end face of the O-ring 26b, and the O-ring 26b is compressed to absorb the kinetic energy of the field part 20 and cause an impact. ease. Thus, even if the O-ring 26b is attached to the end portion of the armature 10, the same effect as that provided on the field magnet portion 20 side can be obtained.

Embodiment 5. FIG.
FIG. 8 is a partially enlarged longitudinal sectional view showing Embodiment 5 of the cylindrical linear motor according to the present invention. As shown in FIG. 8, the cylindrical linear motor 95 according to the fifth embodiment has a cylindrical shape as a cylindrical buffer member at the root (step portion) on the large diameter portion 24 a side of the small diameter shaft portion 24 b of the stepped shaft 24. An elastic body 26c is externally fitted. The cylindrical elastic body 26c is fixed to the small diameter shaft portion 24b of the stepped shaft 24 by its own tightening allowance. Even when the cylindrical elastic body 26c is used in place of the O-ring 26a of the second embodiment, the same effect as the O-ring 26a is obtained.

Embodiment 6 FIG.
FIG. 9 is a partially enlarged longitudinal sectional view showing a sixth embodiment of the cylindrical linear motor according to the present invention, and FIG. 10 shows a deformation state of the buffer member at the time of a collision of the cylindrical linear motor of the sixth embodiment. It is a partial expanded longitudinal cross-sectional view shown. As shown in FIGS. 9 and 10, in the cylindrical linear motor 96 of the sixth embodiment, a cylindrical elastic body 26 d as a buffer member is fitted in the small diameter hole 11 a at the end of the frame 11. The small-diameter shaft portion 24b of the stepped shaft 24 protrudes outside through the cylindrical elastic body 26d without contacting the cylindrical elastic body 26d.

When the field part 20 runs away, the side surface of the large diameter part 24a of the stepped shaft 24 collides with the right end face of the cylindrical elastic body 26d, and the cylindrical elastic body 26d is compressed to absorb the kinetic energy of the field part 20. And relieve shock. Further, as shown in FIG. 10, the cylindrical elastic body 26d is compressed and bulges inward and press-contacts with the small diameter shaft portion 24b of the stepped shaft 24. Therefore, the impact can be reduced by a frictional force. If the cylindrical elastic body 26d is attached to the armature part (stator) 10 side, the weight of the field part (movable element) 20 does not increase, so that the drive characteristics of the field part 20 are not affected.

Embodiment 7 FIG.
FIG. 11 is a partially enlarged longitudinal sectional view showing Embodiment 7 of the cylindrical linear motor according to the present invention. As shown in FIG. 11, in the cylindrical linear motor 97 of the seventh embodiment, a permanent magnet 26 e as a cylindrical or ring-shaped buffer member is fitted in the small diameter hole 11 a at the end of the frame 11. The magnetic pole (S pole) inside the permanent magnet 26e attached to the end of the frame 11 and the magnetic pole (S pole) on the end side of the permanent magnet 22 of the field magnet section 20 are the same magnetic pole. , Repel each other. The small diameter shaft portion 24b of the stepped shaft 24 protrudes outside through the permanent magnet 26e without contacting the permanent magnet 26e.

When the field part 20 runs away, the magnetic pole (S pole) on the end side of the permanent magnet 22 of the field part 20 approaches the magnetic pole (S pole) inside the permanent magnet 26e attached to the end of the frame 11, It can receive a repulsive force in a non-contact manner and can alleviate the impact at the time of collision. If the strong permanent magnet 26e is used, the field part 20 can be stopped without contact. Since the permanent magnet 26e is attached to the armature part (stator) 10 side, the weight of the field part (mover) 20 does not increase, and the drive characteristics of the field part 20 are not affected. In addition, if a cylindrical permanent magnet is used as the permanent magnet 22 of the field magnet portion 20, it can be shared with the permanent magnet 26e attached to the end of the frame 11.

Embodiment 8 FIG.
FIG. 12 is a partially enlarged longitudinal sectional view showing an eighth embodiment of the cylindrical linear motor according to the present invention. As shown in FIG. 12, in the cylindrical linear motor 98 according to the eighth embodiment, a ring-shaped coil (electromagnet) 26 f as a buffer member is fitted into the yoke 12 extending to the end of the frame 11. The small diameter shaft portion 24b of the stepped shaft 24 protrudes to the outside through the coil 26f without contacting the coil 26f.

When the field unit 20 runs away, the magnetic pole (N pole) on the end side of the permanent magnet 22 of the field unit 20 approaches the coil (electromagnet) 26f attached to the end of the frame 11, and the coil (electromagnet) 26f A repulsive force is received in a non-contact manner by the generated magnetic flux, and the impact at the time of collision can be reduced. If the powerful coil (electromagnet) 26f is used, the field part 20 can be stopped without contact. Since the coil (electromagnet) 26f is attached to the armature part (stator) 10 side, the weight of the field part (mover) 20 does not increase, and the drive characteristics of the field part 20 are not affected. The coil 26 f (electromagnet) can be shared with the U, V, and W phase coils 13 u, 13 v, and 13 w of the armature unit 10. The coil (electromagnet) 26f may be a short-circuit coil. In the case of a short-circuit coil, a short-circuit current flows when the magnetic flux of the field part 20 is linked, and can be operated like a dynamic brake.

In the first to eighth embodiments, the armature part 10 is a stator and the field part 20 is a mover. However, the armature part 10 may be a mover and the field part 20 may be a stator.

10 Armature part (stator)
11 Frame 11a Small-diameter hole 12 Yoke 13u U-phase coil 13v V-phase coil 13w W-phase coil 14 Ring-shaped insulating plate 15 Bobbin 16 Bearing holder 17 Bearing 20 Field part (mover)
21 Pipe 22 Permanent magnet 23 Spacer 24 Stepped shaft 24a Large diameter portion 24b Small diameter shaft portion 25 Spring holder 25a Spring holder 25aa Inner flange 25b O-ring holder 26 Coil spring (buffer member)
26a, 26b O-ring (buffer member)
26c, 26d Cylindrical elastic body (buffer member)
26e Permanent magnet (buffer member)
26f Coil (electromagnet, buffer member)
91, 92, 93, 94, 95, 96, 97, 98 Cylindrical linear motor

Claims

A cylindrical frame, a cylindrical yoke made of a magnetic material fitted into the frame, a plurality of ring-shaped coils arranged in the axial direction in the yoke, and fixed to both ends of the frame An armature portion having a bearing;
A large-diameter intermediate portion that is inserted into the armature portion and a plurality of permanent magnets are arranged in the axial direction; and a small-diameter shaft portion that extends from the large-diameter intermediate portion to both axial sides and is inserted into the bearing. A field part formed in a stepped shaft shape;
A cylindrical or ring-shaped cushioning member that is inserted into the frame coaxially with the small-diameter shaft portion and is fixed in the step portion of the field magnet portion or the end portion of the frame.
A cylindrical linear motor comprising:
2. The cylindrical linear motor according to claim 1, wherein the buffer member is a coil spring.
2. The cylindrical linear motor according to claim 1, wherein the buffer member is an O-ring.
2. The cylindrical linear motor according to claim 1, wherein the buffer member is a cylindrical elastic body.
2. The cylindrical linear motor according to claim 1, wherein the buffer member is a permanent magnet.
2. The cylindrical linear motor according to claim 1, wherein the buffer member is an electromagnet.
The cylindrical linear motor according to claim 6, wherein the electromagnet is a short-circuit coil.