WO2013065180A1

WO2013065180A1 - Cylindrical linear motor

Info

Publication number: WO2013065180A1
Application number: PCT/JP2011/075469
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: 2011-11-04
Filing date: 2011-11-04
Publication date: 2013-05-10
Also published as: JPWO2013065180A1; JP5042397B1; TW201320560A

Abstract

The present invention is provided with: an armature unit (10), which has a cylindrical frame (11), a cylindrical yoke (12) made of a magnetic body fitted into the frame (11), a plurality of ring-shaped coils (13u, 13v, 13w) arrayed within the yoke (12) in the axial direction, a bearing holder (16) fixed to two ends of the frame (11), and a bearing (17) held by the bearing holder (16); a field part (20) that is formed in the shape of a stepped shaft and has a large-diameter intermediate part that is inserted into the armature unit (10) and that has a plurality of permanent magnets (22) arrayed in the axial direction, and a small-diameter shaft part (24b) that extends to both sides in the axial direction from the large-diameter intermediate part and is inserted into the bearing (17); and a friction member (19) for generating a static friction force against the small-diameter shaft part (24), the friction member being held by the bearing holder (16) and the small-diameter shaft part (24b) being inserted thereinto.

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).

Further, the stator is movably supported via the rolling member, and is disposed between the left and right inner surfaces of the stator and the left and right outer surfaces of the stator. In the configuration of the linear motor comprising a guide member that controls the track, the guide member that contacts one inner surface side of the stator is formed such that the rotation radius of the portion that contacts the mover and the stator is equal, The other guide member is formed so that the rotation radii of the portions contacting the mover and the stator are different from each other, and when the mover moves relative to the stator, a linear motor that generates a friction braking force by sliding friction A braking mechanism is disclosed (see, for example, Patent Document 3).

JP 2002-355868 A Japanese Patent Application Laid-Open No. 07-232642 (3rd and 4th pages, FIG. 1) Japanese Patent Laid-Open No. 62-193551

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 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. Moreover, there exists a problem that a movable part can be stopped only in the position which collided with the buffer member.

In addition, according to the conventional technique disclosed in Patent Document 3, two types of guide members, one and the other, are used to generate a friction braking force. Therefore, there is a problem that the number of parts is large. Further, since the friction braking force acts only on the other side of the mover, there is a problem that a bending force acts on the mover and an unbalanced load is applied.

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 that has a small number of parts and is low in cost and that does not act on a movable element during driving and braking. .

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. A plurality of ring-shaped coils, a bearing holder fixed to both ends of the frame, and a bearing held by the bearing holder; and an armature portion inserted into the armature portion, and a plurality of permanent coils A field having a large-diameter intermediate portion in which magnets are arranged in the axial direction and a small-diameter shaft portion extending from the large-diameter intermediate portion to both sides in the axial direction and inserted into the bearing, and formed in a stepped shaft shape And a friction member that is held by the bearing holder and through which the small-diameter shaft portion is inserted, and that generates a static friction force between the small-diameter shaft portion.

The cylindrical linear motor according to the present invention has an effect that the number of parts is small and the cost is low, and the bending force does not act on the field part (mover) during driving and braking.

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 shows the necessary effectiveness necessary for reciprocating the mover when the weight of the mover (free fall load) is in the range of 0 kgf to 0.20 kgf when the cylindrical linear motor of Embodiment 1 is installed vertically. It is a figure which shows the calculated value of thrust. FIG. 4 shows a reciprocating drive of the mover when the cylindrical linear motor of the first embodiment is installed vertically, the mover weight is 0.05 kgf (0.49 N), and the static friction force is changed from 0 N to 2 N. It is a figure which shows the calculated value of required effective thrust required for performing. FIG. 5 is a partially enlarged longitudinal sectional view showing Embodiment 2 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, and FIG. 2 is an enlarged view of a portion A in FIG.

As shown in FIGS. 1 and 2, the cylindrical linear motor 91 according to the first embodiment includes a cylindrical armature portion 10 serving 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 includes 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 or columnar permanent magnets 22 arranged in the pipe 21 in the axial direction. And a magnetic metal spacer 23 inserted between adjacent 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 24b of the stepped shaft 24 is supported by the bearings 17 at both ends of the armature portion 10 so as to be linearly movable in the axial direction.

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.

An oil seal or dust seal 19 as a friction member through which the small diameter shaft portion 24b is inserted is held at the outer end portion of the bearing holder 16. The oil seal or dust seal 19 seals oil or dust and applies a static friction force to the small diameter shaft portion 24b. When the cylindrical linear motor 91 is installed vertically, the field portion 20 tends to drop due to gravity, but is held by the static frictional force of the oil seal or dust seal 19 and can be prevented from being damaged due to free fall.

FIG. 3 shows that when the cylindrical linear motor according to the first embodiment is installed vertically, the mover is reciprocally driven when the weight of the mover (field portion 20) (free fall load) is in the range of 0 kgf to 0.20 kgf. It is a figure which shows the calculated value of required effective thrust required for this. As shown in FIG. 3, when the weight of the mover is 0 kgf, the required effective thrust is greater when the static frictional force of the friction member (oil seal or dust seal) 19 is 2N than when it is 1N. However, if the weight of the mover exceeds 0.14 kgf, the required effective thrust becomes smaller when the static friction force is 2N than when it is 1N. This is because the loss can be reduced by supporting the free fall load by the static friction force.

FIG. 4 shows a movable element (field) when the cylindrical linear motor 91 according to the first embodiment is installed vertically, the weight of the movable element is 0.05 kgf (0.49 N), and the static friction force is changed from 0 N to 2 N. It is a figure which shows the calculated value of required effective thrust required in order to reciprocately drive the magnetic part 20). As shown in FIG. 4, when the static frictional force of the friction member 19 is around 0.9 N, the required effective thrust is minimized and the efficiency is increased.

As is apparent from the graph shown in FIG. 4, a cylindrical linear motor is generated by generating a static frictional force between the mover and the stator that is about 1 to 3 times the weight of the mover (0.49N to 1.47N). The required effective thrust of the 91 reciprocating drive can be reduced, and the drive can be performed more efficiently. The same effect as described above can be obtained when the cylindrical linear motor 91 is tilted instead of vertically. When the load connected to the mover (field unit 20) has a constant weight, a static frictional force of about 1 to 3 times the sum of the weight of the mover and the weight of the load is applied to the mover and the stator. Try to generate in between.

The cylindrical linear motor 91 according to the first embodiment is held by the bearing holder 16 through which the small diameter shaft portion 24b is inserted, and a friction member (oil seal or dust seal) 19 that generates a static friction force between the small diameter shaft portion 24b. Therefore, the number of parts is small and the bending force does not act on the small-diameter shaft portion 24b (field portion 20). Moreover, since the oil seal or the dust seal 19 is provided, the armature part 10 can be sealed.

Embodiment 2. FIG.
FIG. 5 is a partially enlarged longitudinal sectional view showing Embodiment 2 of the cylindrical linear motor according to the present invention. As shown in FIG. 5, the cylindrical linear motor 92 according to the second embodiment is movable between the small diameter shaft portion 24b instead of the bearing 17 and the friction member 19 of the cylindrical linear motor 91 according to the first embodiment. A sliding bearing 17a that generates a static friction force that is greater than the weight of the child (field portion 20) and less than three times the weight of the mover is used.

When the load connected to the mover (field portion 20) has a constant weight, a static friction force of about 1 to 3 times the sum of the weight of the mover and the load is applied to the small diameter shaft portion 24b. To be generated. The portions other than the sliding bearing 17a of the cylindrical linear motor 92 of the second embodiment are not different from the cylindrical linear motor 91 of the first embodiment.

According to the cylindrical linear motor 92 of the second embodiment, it is possible to reduce the necessary effective thrust of the reciprocating drive in an inclined installation or a vertical installation state other than the horizontal installation, and it is possible to drive more efficiently.

10 Armature part (stator)
11 Frame 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 17a Sliding bearing 19 Friction member (oil seal, dust seal)
20 Field part (mover)
21 Pipe 22 Permanent magnet 23 Spacer 24 Stepped shaft 24a Large diameter portion 24b Small

diameter shaft portion

91, 92 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 holder and a bearing held by the bearing holder;
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 friction member that is held by the bearing holder and through which the small diameter shaft portion is inserted and generates a static friction force between the small diameter shaft portion;
A cylindrical linear motor comprising:
2. The cylindrical linear motor according to claim 1, wherein the friction member generates a static friction force that is greater than or equal to a weight of the field portion and less than or equal to three times the weight.
2. The friction member generates a static friction force that is greater than or equal to the sum of the weight of the field part and a load connected to the field part and less than or equal to three times the sum. The cylindrical linear motor described in 1.
2. The cylindrical linear motor according to claim 1, wherein the friction member is an oil seal or a dust seal.
A cylindrical frame, a cylindrical yoke made of a magnetic material fitted in 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 holder and a bearing held by the bearing holder;
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;
In a cylindrical linear motor comprising
The bearing is a sliding bearing that generates a static friction force between the small-diameter shaft portion and a weight of the field portion that is greater than or equal to three times the weight of the field portion. Linear motor.
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 holder and a bearing held by the bearing holder;
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;
In a cylindrical linear motor comprising
The bearing generates a static friction force between the small-diameter shaft portion and a sum of a weight of the field portion and a load connected to the field portion and not more than three times the sum. A cylindrical linear motor characterized by being a plain bearing.