JPH087826Y2 - Parts for linear actuators - Google Patents

Description

[Detailed Description of the Invention] [Industrial field of application] The present invention relates to a flat type linear actuator component which is ultra-thin, compact and low in cost. Here, the parts for the linear actuator are the coil unit and the magnet. The linear actuator is composed of a coil and a magnetic circuit, and converts electric energy into mechanical energy of reciprocating motion by using electromagnetic force. For example, linear actuator, linear motor, etc. are shown. .

[Conventional technology]

In recent years, with the great progress and miniaturization and thinning of audio equipment, video equipment, OA equipment and the like, there has been a demand for miniaturization and thinning of linear actuators which generate reciprocating motion among them. Generally, in such a linear actuator, a method of changing the rotary motion created by the motor into a linear motion by using a mechanical mechanism such as a steel belt or a gear has been adopted, but there is a limit to miniaturization and thinning. Therefore, linear actuators that directly generate reciprocating motion have been actively studied recently. Such a linear actuator has a structure in which one or a plurality of spiral coils are arranged on a straight line and face each other, and one or a plurality of magnetic poles are arranged. Recently, a very thin coil, which is made by applying a photolinography technology called a so-called print coil, is used, and the distance (gear tap) between the magnet sandwiching the coil and the yoke plate is used. It became possible to make the magnetic field stronger by making it smaller, and as a result, high thrust could be obtained.

[Problems to be solved by the invention]

However, such a printed coil is used in a small and thin linear actuator as described above, but as shown in FIGS. 1 (A) and 1 (B), the magnets 21 placed facing each other are used.
The volume ratio of the position detecting element 22, for example, a Hall element or a magnetoresistive element and an element having a magnetic detecting function to the coil becomes very large, which makes it difficult to arrange the position detecting element 22 in the linear actuator. For example, as shown in FIG. 1 (B), if the coil unit 23 is to be placed on the coil unit 23, the air gear tape must be made large so that it cannot be caught by the magnet 21 placed oppositely. If the characteristics of the coil are not utilized, and if it is placed outside the main magnetic flux of the magnet 21, the magnetic detection sensitivity will decrease, and it will be necessary to increase the sensitivity of the amplifier for the magnetic detection element, making it difficult to obtain an S / N ratio and increasing costs. .

In addition, since the linear actuator can obtain high thrust in this way, its application has become very widespread.However, especially when it is required to have excellent stability of moving speed, it is newly added. The following problem has arisen.

It is the difference in the magnetic field received by the coil due to the difference in distance from the magnet. For example, as shown in FIG. 1, a coil unit 23
In many cases, since a plurality of print coils are superposed on each other, the distance from the magnet to each print coil is naturally different. Then, the distance between the magnet 21 and the yoke plate 24 is about 1 to 3 m / m, and the strength of the magnetic field becomes weaker as it goes from the magnet surface to the yoke plate surface, although it is very slight.

The imbalance of the force exerted on the magnet of the print coil due to the difference in the magnetic field at the place where each print coil exists (the coil closer to the magnet exerts a larger force on the magnet than the coil closer to the yoke plate). ) Causes a very subtle speed unevenness.

[Means / actions for solving problems]

The present invention relates to a small and thin linear actuator component that solves the above problems.

 That is, the present invention relates to the following.

A linear actuator comprising the following (a), (b), and (c), wherein the magnetic detection element is embedded only in the print coil closest to the magnet among the print coils forming the coil unit. Parts.

(A) Magnet 2 whose width is 1 in the direction perpendicular to the sliding direction
1.

(B) A plurality of spiral-shaped conductor patterns 3 arranged in the sliding direction at regular intervals.

(C) Outside the spirally wound conductor pattern 3, the distance R from the center of the magnet 21 in the width direction is R ≦ l / 2 + d (where d is
The magnetic sensing element 8 is arranged such that the sensing portion of the magnetic sensing element 8 is located at a distance R, which is the distance from the surface of the magnet facing the print coil unit to the surface of the print coil unit opposite to the magnet). Embedded film thickness is 0.1 to 2
A print coil unit 23 including a plurality of mm print coils 1 is generally referred to as a coil unit, which is a coil unit. In the case of a coil unit using print coils, a plurality of print coils are laminated. In many cases, a coil unit is constructed.

The magnet used in the present invention may be made of any material,
Ferrite and rare earth materials such as samarium and cobalt are preferably used. The thickness of the magnet is preferably 0.2-10 m / m.

The shape is basically a rectangular parallelepiped, but it may be deformed depending on the shape of other parts to be combined. The magnet has a width equal to the moving direction of the coil or the magnet, and is alternately polarized with N and S in a direction perpendicular to the surface facing the coil. One example is shown in FIG.

The printed coil used in the present invention may be manufactured by any manufacturing method, for example, an etching method, a plating method or a combination thereof, but it is disclosed in JP-A-57-91590. Printed coils manufactured by the described manufacturing method are preferred. The effect is exhibited when the thickness of the printed coil is 0.1 to 2 mm. The linear density of the coil portion is 2 to 20 wires / mm, more preferably 5 to 20 wires / mm. FIG. 3 shows an example of a print coil used in the present invention. A spiral pattern 3 is formed on both sides of the print coil support 2 with the same pitch as the magnetized poles, and if necessary, through holes 6 are provided on both sides of the print coil support 2. The conductive patterns 3 are connected so as to be conductive. The printed coil support 2 may be of any type as long as it has electrical insulation properties, and for example, a glass epoxy substrate, a polyimide film, an epoxy resin or the like is preferably used. or,
The through hole 6 may be formed by any method.

In the coil pattern 3, a spirally wound conductor pattern is arranged with the same pitch as that in which the counter magnets are alternately magnetized as N poles and S poles.

In general, the centers of the spirally wound conductor patterns are arranged in the same straight line and coincide with the moving direction of the movable portion (coil or magnet).

The position on the print coil in which the magnetic detection element 8 is embedded needs to satisfy two conditions at the same time. The first condition is that the distance from the center of the magnet and the magnetic field as shown in FIG. 4 (B). As can be seen from the graph of the strength relationship of R, if the distance from the center of the magnet in the width direction to the sensing portion of the magnetic detection element 8 is R, then R ≦ l / 2 + d (1d is the surface of the magnet print coil unit). Distance from the surface to the side opposite to the magnet of the print coil unit), and R ≦ l / 2 + 0.5 ×
It is preferably d. When R is larger than l / 2 + d, the magnetic field becomes weak and the accuracy of magnet position detection deteriorates. Here, the sensing unit is a place in the magnetic detection element 8 that has the ability to really convert the strength of the magnetic field into an electric signal. Further, it is always important from the magnetic detection principle to evaluate the distance R by the distance to the center of the sensitive section. The second condition for embedding the magnetic detecting element is preferably between the spirally wound conductor patterns 3 except for the spirally wound conductor pattern 3 and the central portion 5.

When the magnetic detection element 8 is arranged inside the spiral-shaped conductor pattern 3, that is, in the central portion 5 (the maximum detection magnetic field), the connection circuit of the magnetic detection element 8 must be provided so as to cross the spiral-shaped conductor pattern 3. Therefore, the distance between the yoke plate 24 and the magnet 21 becomes longer than the sum of the spirally wound conductor pattern 3 and the connection circuit, and the original force of the magnet is reduced. On the other hand, when the magnetic detection element 8 is embedded between the spirally wound conductor patterns 3, it is not necessary to provide a connecting circuit so as to cross the spirally wound conductor pattern 3, and only the thickness of the printed coil is enough to provide the magnet and the yoke plate. The distance between and can be designed, an actuator can be manufactured that maximizes the original force of the magnet, and the actuator can be made extremely simple. Furthermore, the plurality of magnetic detection elements is one of the print coils that form the coil unit.
It must be embedded in a single printed coil. When the magnetic detection elements are embedded over a plurality of printed coils in the coil unit, the distance from the magnet to each magnetic detection element is slightly different, and the strength of the magnetic field received by each magnetic detection element is slightly different. As a result, the switching timing of the current flowing through each coil is slightly deviated.

It is also desirable to consider the following regarding the arrangement on the print coil. Two or more magnetic detection elements are arranged in equal pitches depending on the driving method, but in many cases the arrayed pitches do not match the arrayed pitches of the spiral-shaped conductor pattern. In other words, even if one magnetic detection element is arranged in the vacant space between the spiral-shaped conductor patterns, the positions of the other magnetic detection elements overlap with the spiral-shaped conductor pattern.
For example, as shown in FIG. 5 (B), a portion of the spirally wound conductor pattern that contributes to the linear actuator thrust is partially sacrificed to slightly deform the pattern, and the magnetic sensing element is embedded therein. As a result, the force generated by the coil closer to the magnet can be reduced, and the force generated by the coil farther from the magnet can be matched.

Further, it is preferable to collect the magnetic detection elements on the print coil closest to the magnet among the print coils forming the coil unit. Then, the magnetic fields received by the magnetic detection elements are made equal, the output voltage of each element is made uniform, and the coil pattern is deformed to arrange the magnetic detection elements, so that the thrust of the linear actuator of the print coil closest to the magnet is thrust. By reducing the contribution to the thrust force of each print coil, the contribution to the thrust force of each print coil can be made uniform at the same time.

Any method may be used for embedding the magnetic detection element in the printed coil. For example, a hole may be formed by pressing according to the external dimensions of the element, the element may be inserted into the hole and fixed with the adhesive 12. In this case, for example, an epoxy or phenol adhesive is used.

Any magnetic detection element may be used as long as it can detect magnetism, and examples thereof include a hall element, a micro coil, and a magnetic resistance element.

The element may have any thickness, but is preferably thinner than the thickness of the printed coil to which the element is attached. If the element is thinner than the thickness of the printed coil, it is not necessary to deform the spiral-shaped conductor pattern of the printed coil other than the printed coil in which the element is attached in the coil unit according to the position and shape of the element. The degree of freedom in designing the conductor pattern increases. The shape of the element may be any shape, but a pentagon or a triangle is preferable especially when the element is arranged in a region in which the corners of the spiral-wound conductor pattern are rounded and deformed, facing the outer periphery.

As described above, a plurality of print coils each containing a magnetic detection element and a plurality of print coils not including a magnetic detection element are laminated to form a coil unit.

Any material may be used for this stacking as long as the coils can be fixed and insulation between the coils can be taken. For example, an epoxy-based or phenol-based adhesive, or a semi-cured adhesive on both sides of the insulating film. You may use the adhesive agent sheet apply | coated. FIG. 6 shows an example.

〔effect〕

The coil unit and the magnet with the built-in magnetic sensor of the present invention have a large thrust because the efficient magnetic circuit can be obtained because the coil unit including the magnetic sensor is thin.
Since there is little variation in the output due to the difference in the magnetic field of each magnetic detection element, the timing of switching the current to each coil is accurate, and since the contribution to the thrust of each print coil is made uniform, a high stable movement speed is achieved. A thin linear actuator with

[Brief description of drawings]

1 (A) and (B) are a general sketch and a sectional view of a linear actuator. 2 (A) and 2 (B) are a plan view and a front view of one embodiment of a magnet used in the present invention.
FIG. 3 shows an example of a print coil used in the present invention. FIG. 3 (A) is a plan view and FIG. 3 (B) is a cross section taken along the line AA ′ in FIG. 3 (A). It is a figure. 4 (A) and 4 (B) are a cross-sectional view of the actuator component of the present invention and a graph showing the relationship between the distance from the center of the magnet in the width direction and the magnetic field strength. FIG. 5 is a plan view of an example of a printed coil in which a magnetic detecting element used in the present invention is embedded. 6 (A), (B) and (C) are a front plan view, a back plan view and BB 'of an example of the coil unit used in the present invention.
It is sectional drawing in a line. 1,1 ′ …… Print coil 2,2 ′ …… Print coil support 3,3 ′ …… Spiral conductor pattern 4,4 ′ …… Through hole land 5,5 ′ …… Spiral conductor pattern Central part 6,6 ′ …… Through hole 7,7 ′ …… External connection terminal 8,22 …… Magnetic detection element 9,9 ′ …… Insulation overcoat resin 12 …… Adhesive agent 13 …… Magnetic detection element Embedding hole 21 …… Magnet 23 …… Coil unit 24 …… Yoke plate

 ─────────────────────────────────────────────────── ─── Continuation of the front page (56) References JP-A-59-103559 (JP, A) JP-A-57-91590 (JP, A) JP-A-58-86861 (JP, A) Actual development Sho-59- 97596 (JP, U)

Claims (1)

[Scope of utility model registration request] 1. A magnetic detection element consisting of the following (a), (b), and (c), wherein a magnetic detection element is embedded only in the print coil closest to the magnet among the print coils constituting the coil unit. Parts for linear actuators. (A) Magnet 2 whose width is 1 in the direction perpendicular to the sliding direction
1. (B) A plurality of spiral-shaped conductor patterns 3 arranged in the sliding direction at regular intervals. (C) The distance R from the center of the magnet 21 in the width direction on the outside of the spirally wound conductor pattern 3 is R ≦ l / 2 + d (however, d
From the surface of the magnet facing the print coil unit,
At the position of a distance R, which is the distance (to the surface of the print coil unit opposite to the magnet), the film thickness in which the magnetic sensing element 8 is embedded so that the sensing portion of the magnetic sensing element 8 is located.
A print coil unit 23 that includes a plurality of print coils 1 of 0.1 to 2 mm.