JPH11299211A - Oscillating actuator - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide an oscillating actuator from which sufficiently large holding torque can be obtained. SOLUTION: A pair of yoke-side permanent magnets is provided to each of paired yokes facing each other, in such a state, that the magnets face opposite to each other. In the magnetic clearance between the yoke-side permanent magnets, a coil holder 14 which is connected to a shaft provided between the yokes through a bearing member is provided. A movable coil 16 is integrally provided to the coil holder 14 and permanent magnets 17 for latching are provided to the end section of the coil holder 14.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention is used in various applications such as swinging a sorter plate for changing the course of articles sent on a traveling path in an automatic mail sorting system or the like, positioning a magnetic head, and the like. Related to a swing type actuator.

[0002]

2. Description of the Related Art An oscillating actuator is widely used for positioning a magnetic head when reading / writing data from / on a disk by the magnetic head. As such an oscillating actuator, both a movable magnet type and a movable coil type are well known.

In a movable magnet type swing actuator, a latch member such as a ferromagnetic iron piece is provided on a coil side of a stator, and rotation of a driving magnet is provided by a latch member on the stator side. It stops at the position.

There is known a movable coil type swing type actuator in which a ferromagnetic material such as a latch iron piece provided on a movable coil is attracted and latched on a magnet side of a stator.

[0005]

Oscillating actuators are often used for positioning a magnetic head when reading / writing a disk as a magnetic recording medium. Recently, however, the oscillating actuator can oscillate at high speed. Focusing on this point, use for applications other than magnetic heads has been actively considered.

In a conventional swing type actuator used for positioning a magnetic head, components such as the magnetic head itself are smaller and lighter than the original components. The holding torque at the stop position and the starting torque in the data zone (read / write zone) are not required to be so large.

However, in fields other than such magnetic heads,
For example, if the field of use is expanded for controlling the rotation angle of an industrial machine, the torque often becomes a problem. Unlike conventional magnetic recording devices, which have become lighter and smaller, a large torque is often required.

[0008] Neither the conventional movable-magnet type or movable-coil type oscillating actuators provide a large torque that can be used in industrial machines. Latch members such as iron pieces provided on coils on the stator side by utilizing the leakage magnetic flux of the movable magnet for motor rotation or the magnets on the stator side,
Alternatively, since a latch member such as an iron piece provided on the movable coil side is magnetically attracted and latched, sufficient starting torque and holding torque (torque for locking to the initial position) cannot be obtained. is the current situation.

An object of the present invention is to provide a swing type actuator capable of obtaining a sufficient torque.

[0010]

According to the present invention, there is provided an oscillating actuator comprising: a yoke forming a magnetic circuit; a pair of yoke-side permanent magnets provided on the yoke and magnetized in a thickness direction;
And a stator provided on the yoke and having a bearing member for holding a shaft, the shaft connected to the swingable member, a coil holder connected to the shaft and provided with a latching permanent magnet, provided integrally with the coil holder. A movable element having a bobbin-less movable coil, wherein the movable coil is provided in a magnetic gap formed between the pair of yoke-side permanent magnets, and the latching permanent magnet is provided in the coil holder. The movable coil is provided at both ends in the swing direction of the movable coil.

The yoke-side permanent magnet and the latching permanent magnet include R (one or more rare earth elements) —Fe—B
Rare-earth sintered magnet or rare-earth bonded magnet of any one of R, R (one or more rare earth elements) -Co type is used.

The permanent magnet for latch provided integrally with the coil holder is preferably provided on both ends of the coil holder outside the swing range of the movable coil.

R (one or more rare earth elements) -Fe- used for the yoke-side permanent magnet and the latch permanent magnet
Examples of the B-based and R (one or more rare earth elements) -Co-based rare-earth permanent magnets include, for example, R-Fe-B-based rare-earth permanent magnets such as neodymium-boron-based rare-earth magnets. In this case, one or more rare earth elements such as Nd and Pr may be selected as R. R
Examples of the -Co rare earth permanent magnet include a samarium-cobalt rare earth magnet. In this case, one or more rare earth elements such as Sm and Ce may be selected as R.

These rare earth permanent magnets may be either sintered magnets or bonded magnets. By using a rare-earth magnet having a strong magnetic force for the yoke-side permanent magnet and the latching permanent magnet, the size can be reduced as compared with a case where a ferrite magnet having a weak magnetic force is used. The coil holder is
Although it is integrally formed with the movable coil and the shaft by insert molding (injection molding), at the time of this molding, it is broken by a ferrite magnet, but rare earth permanent magnets do not suffer from this crack.

The insert molding of the coil holder is performed, for example, by using polyphenylene sulfide resin, polybutylene terephthalate resin, polyamide resin, polyimide resin,
A known resin (preferably a resin having heat resistance) such as a polyamideimide resin or a polyester resin can be used.

Among the above resins, the longitudinal elastic modulus (measuring method: AST
(MD-638) is preferably 10 × 10 ⁴ kg / cm ² or more (preferably 13 × 10 ⁴ kg / cm or more). In particular, it is preferable to use a liquid crystal polyester resin (a polyester having a rigid straight chain in the main chain), which is a kind of liquid crystal polymer (having liquid crystallinity in a molten state), as the thermoplastic resin.

[0017]

Embodiments of the present invention will be described below in detail with reference to the drawings.

FIG. 1 is a cross-sectional view of a main part showing a state of a magnetic circuit of a swing type actuator. FIG. 2 is a plan view as seen from the direction of A in FIG. 1, and FIG. 3 is a plan view as seen from the direction of B in FIG.

On the stator A side, as shown in FIG. 1, a yoke 10a formed in a cap shape is provided so as to cover a yoke 10b formed in a plate shape to form a housing. Bearing members 11 through which shafts 12 pass are provided on the end side of the ceiling surface of the yoke 10a and on the side of the yoke 10b opposed thereto. The bearing member 11 is configured as a sintered oil-impregnated bearing, and is maintenance-free without requiring lubrication. This bearing member 11
Are caulked and fixed to the yokes 10a and 10b.

As shown in FIG. 1, a shaft 12 is passed through the bearing member 11. A swinging member such as a swinging member (not shown) for swinging at high speed for opening / closing and switching is attached via the shaft 12. A connection hole 12a is made to penetrate the shaft 12 so as to traverse the longitudinal direction, and a connection of a swing member or the like can be performed with the connection hole 12a.

The swing member is formed, for example, by providing a plate-shaped member on a swinging rotating shaft, and swinging the plate surface at a branch portion of the traveling path through which the sorted products flow, so that the flowing products can be removed. It is conceivable to configure so that the traveling direction can be changed. In addition to sorting, opening and closing at high speed may be considered.

A coil holder 14 integrally formed with a shaft 12 is swingably interposed between the two bearing members 11 on the yoke 10a side and the yoke 10b side.
Is configured. By the swing of the coil holder 14, the shaft 12 integrated with the coil holder 14 is also rotated.

As shown in FIG. 4A, the coil holder 14 is composed of a carriage portion 14a having a shaft 12, and a holder body 14b containing a substantially fan-shaped bobbin-less movable coil 16 inside. . Holder body 14
b, a permanent magnet for latch 1 indicated by a broken line in the figure
7 is embedded. The carriage portion 14a, the holder main body 14b, the movable coil 16, and the cylindrical permanent magnet 17 for latch are integrally formed by resin molding.

A metal carriage portion 14a, a movable coil 16 and a latch permanent magnet 17 are arranged in a holder insert die, and are integrally formed by injection molding of PPS (polyphenylene sulfide) resin.
In addition to the PPS resin (polyphenylene sulfide resin), a thermoplastic resin such as a polybutylene terephthalate resin can be used.

The permanent magnet for latch 17 is shown in FIG.
As shown in (b), the movable coil 16 is formed in a small columnar shape magnetized in the axial direction, and is provided at a position outside each end of the swing range of the movable coil 16. As the latching permanent magnet 17, a permanent magnet having a large (BH) _max (maximum energy product) is used. For example, Nd
-Fe-B system (neodymium-iron-boron system), Sm-C
An o-based (samarium-cobalt-based) permanent magnet may be used. The permanent magnet having such a configuration may be a bonded magnet, a sintered magnet, or any form.

The yokes 10a, 10 constituting a magnetically closed circuit
b, as shown in FIGS. 1 and 5, the inner surface of the yoke 10b and the inner surface of the yoke 10a face each other, and the inner surfaces of the opposed yokes 10a and 10b have a flat yoke side. Permanent magnets 20a and 20b are provided. The yoke-side permanent magnets 20a and 20b are opposed to each other with a magnetic gap at a distance that allows the movable coil 16 to be interposed therebetween.

The yoke-side permanent magnets 20a and 20b are shown in FIG.
As shown by a broken line in FIG.
It is formed on a permanent magnet magnetized in its thickness direction so that the pole and the S pole appear. Yoke-side permanent magnets 20a, 20
b is (BH) like the permanent magnet 17 for latch.
Nd-Fe-B-based (neodymium-iron-boron-based) and Sm-Co-based (samarium-cobalt-based) permanent magnets having a large _max (maximum energy product) are used. Such a permanent magnet may be a bonded magnet, a sintered magnet, or any form.

Incidentally, the latching permanent magnet 17 having the above-described structure is used.
Is configured so that the magnetic force is slightly larger than the yoke-side permanent magnets 20a and 20b, and the lock force at the time of stoppage of swing is large and is reliably held.

As shown in FIG. 4 (a), the movable coil 16 formed in a substantially fan shape has a winding start end and a winding end end, as shown in FIG. 18b, the lead wire 19 (19a, 19
b).

In the oscillating-type actuator configured as described above, by supplying a current to the movable coil 16,
In accordance with Fleming's left-hand rule, a driving force is applied to the movable coil 16 in a direction rotating around the bearing member 11, and the coil holder 14 is rotated around the bearing member 11. By changing the direction of the current flowing through the coil 16, the direction of the driving force is changed left and right, and the coil holder 14 is swung right and left from the center position shown in FIG. The shaft 12 is also swung by the swing of the coil holder 14, so that, for example, a swing member attached to the shaft 12 is opened and closed at a high speed, for example.

The coil holder 14 is, as shown in FIG.
15 from the center of the movable coil 16 (see FIG. 4)
Each was set to have a swing range of 30 degrees in total. The setting of the swing range is configured so that the swing range can be defined by a swing member or the like connected to the shaft 12. The swing range of the swing actuator is regulated by, for example, a stopper member on the swing member side connected to the swing actuator via the shaft 12. In the present embodiment, no stopper member for defining the swing range is provided on the swing type actuator side.

In FIG. 6A, 15 degrees are leftward,
(B) shows a state in which it has been swung 15 degrees to the right.
FIG. 7 shows a case where the input current is set to 0.5 A.
6A to 6B show torque distribution diagrams when the movable coil 16 swings. In the horizontal axis of FIG. 7, when the movable coil 16 is at the position of FIG.
Assuming that the position at the position (b) is 30 degrees, the movable coil 1
6 shows a torque situation at the swing position (indicated by an angle) of No. 6.

Since the torque generated by the movable coil 16 and the torque generated by the latching permanent magnet 17 are in the same direction, the combined torque is shown. Torque measurements were taken from 0 ° (latched) to 30 ° (latched on the opposite side). This is the moment when the pressure is rapidly released from 400 g · cm.

At 15 ° (when the mover is not swinging to either direction), the torque generated by the movable coil 16 and the latching permanent magnet 17 is canceled out at about 200 g · cm immediately before 30 °. Get closer.

FIG. 8 shows the oscillating-type actuator having the above-described configuration in the case where no current flows through the movable coil 16, that is, the torque generated by the permanent magnet 17 for latching. Is obtained. FIG. 9 shows a state of a torque distribution in an oscillating actuator in which the permanent magnet 17 for latch is not provided and the other configuration is the same as the above configuration. From the comparison between FIGS. 8 and 9, in the swing type actuator without the latching permanent magnet 17, the torque substantially uniformly shows about 200 g · cm, but when the latching permanent magnet 17 is provided, the holding position is changed. It can be seen that the torque suddenly decreases and the rocking becomes easy after that.

FIG. 10A shows the distribution of the air gap magnetic flux density, which is a value measured up to 20 mm along the direction of arrow Y shown in FIG. 10B. Similarly, FIG.
The state of the distribution of the air gap magnetic flux density described in FIG.
This is a value measured up to 20 mm in the Y ′ direction shown in FIG. The directions of both Y and Y 'are symmetrical to each other,
The air gap magnetic flux density at each position is shown in the direction of the arrow. Arrow Y (Y ') of yoke-side permanent magnets 20a and 20b
Is measured from a position 2 mm in front along.

[0037]

According to the present invention, the holding torque can be increased.

According to the present invention, the starting torque can be increased.

According to the present invention, the locking force can be increased.

In the present invention, since the holding torque and the starting torque can be increased, the weight of the oscillating member connected to the oscillating actuator can be increased accordingly, and the oscillating movement to the industrial machine can be increased. Applications of the mold actuator can be expanded.

[Brief description of the drawings]

FIG. 1 is a sectional view of a main part of an oscillating actuator according to an embodiment of the present invention.

FIG. 2 is a front view as viewed from a side A in FIG. 1;

FIG. 3 is a rear view as viewed from a side B in FIG. 1;

FIG. 4A is a plan view showing a movable coil provided in a coil holder. (B) is a sectional view of (a).

FIG. 5 is a sectional view of a main part of the swing type actuator.

FIGS. 6A and 6B are explanatory diagrams showing a situation where a swung movable coil is positioned at an end of a swing range.

FIG. 7 is a graph showing a torque distribution.

FIG. 8 is a graph showing a distribution of holding torque.

FIG. 9 is a graph showing a torque distribution when no latch permanent magnet is provided.

10A is a plan view of a main part showing a measurement direction of air gap magnetic flux density along an arrow direction, and FIG. 10B shows a distribution of air gap magnetic flux density obtained by the measurement of FIG. It is a graph.

11A is a plan view of a main part showing a measurement direction of the air gap magnetic flux density along the direction of the arrow, and FIG. 11B shows a distribution of the air gap magnetic flux density obtained by the measurement of FIG. It is a graph.

[Explanation of symbols]

 10a Yoke 10b Yoke 11 Bearing member 12 Shaft 12a Through hole 14 Coil holder 14a Carriage part 14b Holder body 16 Moving coil 17 Latching permanent magnet 18a Terminal pin 18b Terminal pin 19 Lead wire 19a Lead wire 19b Lead wire 20a Yoke side permanent magnet 20b Yoke side permanent magnet A Stator B Mover

Claims (2)

[Claims] A yoke forming a magnetic circuit, a pair of yoke-side permanent magnets provided on the yoke and magnetized in a thickness direction, and a stator provided on the yoke and having a bearing member for holding a shaft; The movable coil having a bobbin-less movable coil integrated with the shaft, a coil holder coupled to the shaft and provided with a latching permanent magnet, and a bobbin-less movable coil integrated with the coil holder; It is provided in a magnetic gap formed between the pair of yoke-side permanent magnets, and the latching permanent magnets are provided at both ends of the coil holder in the swing direction of the movable coil. Swinging actuator. 2. The swing-type actuator according to claim 1, wherein the yoke-side permanent magnet and the latching permanent magnet are R
(1 or more elements of rare earth elements) -Fe-B-based or R (one or more elements of rare earth elements) -Co-based rare earth sintered magnets or rare earth bonded magnets are used. Swinging actuator.