JP2019048273A - Electromagnetic actuator and electronic equipment - Google Patents

Abstract

To prevent variations in the quantity of a magnetic fluid.SOLUTION: An electromagnetic actuator comprises a guiding surface 21, a movable element 30 that vibrates along the guiding surface 21, a magnetic fluid 50 present between the movable element 30 and the guide surface 21, and a coil 20 that vibrates the movable element 30 by magnetic action. The movable element 30 is provided with a magnet 31 and an auxiliary member 32 integrally so that they are arrayed in a direction along the guide surface 21. The auxiliary member 32 has an opposed surface 32a1 that approaches to or makes contact with an end surface 31a of the magnet 31 in the direction along the guiding surface 21, and the end surface 31a of the magnet 31 projects further to the guide surface 21 side than the opposed surface 32a1.SELECTED DRAWING: Figure 3

Description

  The present invention relates to an electromagnetic actuator configured to vibrate a mover having a magnet, and an electronic device provided with the electromagnetic actuator.

Conventionally, in this type of invention, for example, as described in Patent Document 1, a weight having a hollow portion on the center side, a magnet fitted and fixed to the hollow portion, and a predetermined position on the lower side of the magnet There is a vibration motor in which a magnetic fluid is filled in the gap and the gap between the magnet and the inner surface of the cover, and a coil disposed with a gap between them and a cover that covers the weight and the magnet from the upper side.
According to this vibration motor, the magnetic fluid can be made to function as a damper when the vibration body consisting of the weight and the magnet vibrates, and the magnetic fluid can be made magnetic even if the vibration body vibrates. To stay on the top and bottom sides of the magnet.

JP 2017-77153 A

  However, according to the above-mentioned prior art, a slight gap is formed between the inner surface of the hollow portion and the outer surface of the magnet due to dimensional dispersion or the like, and the magnetic force is generated in this gap by capillary force. Fluid may penetrate. The amount of penetration varies depending on the size of the gap, so the actual amount of the magnetic fluid remaining on the upper and lower surfaces of the magnet varies, and as a result, the effect of the magnetic fluid also varies.

In order to solve such a subject, the present invention comprises the following composition.
A guide surface, a mover vibrating along the guide surface, a magnetic fluid interposed between the mover and the guide surface, and a coil for vibrating the mover by magnetic action, the mover The magnet and the auxiliary member are integrally provided so as to line up in the direction along the guide surface, and the auxiliary member has an opposing surface that approaches or contacts the end face of the magnet in the direction along the guide surface. An electromagnetic actuator characterized in that the magnet projects the end face toward the guide surface more than the opposing surface.

It is an exploded perspective view showing an example of an electromagnetic actuator concerning the present invention. It is a top view of the same electromagnetic actuator, and shows the state where the cover was removed. It is a longitudinal cross-sectional view of the same electromagnetic actuator. It is a principal part enlarged view showing an example of a mover. It is a longitudinal cross-sectional view which shows the other example of the electromagnetic actuator which concerns on this invention. It is a perspective view which shows an example of the electronic device provided with the same electromagnetic actuator.

  Hereinafter, embodiments of the present invention will be described with reference to the drawings. In the following description, the same reference numerals in different drawings denote portions having the same functions, and redundant description in each drawing will be appropriately omitted.

1 to 4 show an example of an electromagnetic actuator according to the present invention.
The electromagnetic actuator 1 includes a coil 20 having a guide surface 21 in a housing 10, a mover 30 vibrating along the guide surface 21, and a biasing member 40 supporting the mover 30 in a reciprocating manner. A magnetic fluid 50 is interposed between the magnet 31 and the guide surface 21, and the mover 30 is vibrated along the guide surface 21 by the magnetic action between the coil 20 and the magnet 31.

  The housing 10 is formed of stainless steel in a flat hollow box shape, and according to the illustrated example, the upper surface of the rectangular flat plate base plate 11 is configured to cover the flat box lid 12 opened downward. Be done.

The coil 20 is formed in an annular and flat shape extending in the vibration direction, and is fixed to the base plate 11 via an adhesive.
The surface on the side opposite to the base plate of the coil 20 functions as a guide surface 21 for guiding the mover 30 in the vibration direction via the magnetic fluid 50 described later. The guide surface 21 is one end surface in the axial direction of the flat coil 20, and is formed in a substantially flat surface.
A feed terminal (not shown) of the coil 20 is exposed from the bottom surface of the base plate 11 in a state of being connected to the coil 20.

  The mover 30 integrally includes a magnet 31 and an auxiliary member 32 (a weight) so as to be aligned in a direction along the guide surface 21 of the coil 20 (X direction and Y direction according to the illustrated example).

The magnet 31 has magnetic poles N and S opposite to each other on both sides in the vibration direction on the surface 31 c along the guide surface 21. The magnet 31 has end faces 31a and 31b substantially orthogonal to the guide surface 21 at both ends in the vibration direction (X direction) and at both ends in the cross direction (Y direction) with respect to the vibration direction (FIG. 1). reference).
The illustrated magnet 31 has one magnet part M1 having magnetic poles N and S on both sides in the thickness direction (Z direction) and the other magnet having opposite magnetic poles S and N on both sides in the thickness direction (Z direction). The part M2 is joined in the direction of vibration, and it is also possible to form a Halbach arrangement or the like as required.

The auxiliary member 32 is a weight according to the illustrated example, and is formed of a metal material having a relatively high specific gravity such as tungsten.
The auxiliary member 32 has a fitted portion 32 a fitted to the circumferential side surface of the magnet 31. The fitted portion 32 a is a rectangular hole penetrating the auxiliary member 32 in the thickness direction (Z direction), and the magnet 31 is fitted therein.
The auxiliary member 32 has the inner side surfaces of the rectangular holes as opposing surfaces 32a1 and 32a2 which are close to or in contact with the end surfaces 31a and 31b of the magnet 31.

The magnet 31 is fitted and fixed to the fitted portion 32a so as to protrude toward the guide surface 21 side.
That is, the end surfaces 31 a and 31 b of the magnet 31 project more toward the guide surface 21 than the facing surfaces 32 a 1 and 32 a 2 of the auxiliary member 32. Therefore, as shown in FIGS. 3 and 4, a step d is secured between the surface on the guide surface 21 side of the magnet 31 and the surface on the guide surface 21 side of the auxiliary member 32 (see FIG. 3). .
Although not shown, the step d is formed on both sides of the magnet 31 also in the direction (Y direction in the drawing) intersecting the vibration direction.

  The means for fixing the magnet 31 fitted to the fitted portion 32a can be, for example, bonding, welding, fitting, screwing or the like.

Two biasing members 40 are provided so as to be positioned on both sides in the vibration direction of the mover 30.
Each biasing member 40 is a metal plate spring, and connects one end side in the biasing direction to the biasing member 40 and the other end side to the side wall of the lid 12.
As another example of the biasing member 40, it is also possible to use a leaf spring, a coil spring, or the like having a shape other than the illustrated example.

The magnetic fluid 50 is a well-known fluid having a property of being attracted to a magnet, and, for example, ferromagnetic fine particles such as magnetite and manganese zinc ferrite, surfactants covering the surface, base solutions (water and oil), etc. It comprises.
The magnetic fluid 50 is filled so as to fill the gap between the surface 31c along the guide surface 21 of the magnet 31 and the guide surface 21 (see FIG. 3), and is held on the surface 31c of the magnet 31 by its magnetic attraction force. , Improve the vibration characteristics of the mover 30, or function as a damper.

Next, the characteristic effects and advantages of the electromagnetic actuator 1 configured as described above will be described in detail.
Slight gaps s1 and s2 are formed between the peripheral side surfaces (end faces 31a and 31b) of the magnet 31 and the inner side surfaces (opposing surfaces 32a1 and 32a2) of the auxiliary member 32 due to dimensional dispersion or the like. (Figure 2). In addition, the amount of the magnetic fluid 50 filled between the magnet 31 and the guide surface 21 may increase or decrease due to variations in manufacturing operation or the like.
Further, the magnetic fluid 50 may protrude to both sides in the vibration direction due to the vibration of the mover 30, or may protrude to the outside of the circumferential side surface of the magnet 31 due to a drop impact or the like.
However, according to the electromagnetic actuator 1 having the above-described configuration, even if the magnetic fluid 50 protrudes as described above, the flow of the magnetic fluid 50 into the gaps s1 and s2 decreases and decreases as shown in FIG. Can be blocked by
Therefore, the actual amount of the magnetic fluid 50 remaining on the surface 31 c of the magnet 31 can be stabilized, and in turn, the damper effect by the magnetic fluid 50 (specifically, the effects of noise reduction, fall time reduction, etc.) is improved. At the same time, it is also possible to shorten the distance between the magnet 31 and the coil 20 to improve the thrust.

According to the above embodiment, although the fitting portion 32a of the auxiliary member 32 is a through hole, as another example, the fitting portion of the auxiliary member 32 as in the electromagnetic actuator 1 'shown in FIG. It is also possible to make 32a 'into a rectangular recess.
According to the electromagnetic actuator 1 ′, similarly to the electromagnetic actuator 1, the magnetic fluid 50 can be prevented from entering and reducing the gap s 1 around the magnet 31, and the bottom surface of the fitted portion 32 a ′ and the magnet 31 An adhesive can be interposed on a relatively large area between them to bond them, and the adhesive strength of the magnet 31 can be improved.

Next, a portable electronic device 100 will be described as an example of the electronic device equipped with the electromagnetic actuator 1 (or 1 ′) according to the embodiment of the present invention (see FIG. 6).
In the portable electronic device 100, the electromagnetic actuator 1 (or 1 ') is mounted in a thin flat box-like casing to constitute a portable information terminal (for example, a smartphone, a tablet personal computer, etc.).
According to this configuration, stable vibration can be obtained by the electromagnetic actuator 1 (or 1 '), and thinning and downsizing in the width direction are possible, and different operation start and end times in the communication function such as incoming call and alarm function A stable vibration that hardly generates sound can be transmitted to the user with high responsiveness.
Moreover, the magnetic fluid 50 intrudes into the gaps s1 and s2 around the magnet 31 due to the variation in the filling amount of the magnetic fluid 50, the drop impact, etc., and the magnetic fluid 50 stays between the magnet 31 and the guide surface 21. The configuration such as the step d can prevent the amount from fluctuating or decreasing. Therefore, it is possible to obtain the portable electronic device 100 having high impact resistance and durability, high life and resistance to failure.

  According to the above embodiment, the guide surface 21 is provided on the coil 20. However, as another example, the inner surface of the lid 12 is a guide surface, and the magnetic fluid 50 is interposed between the guide surface and the magnet 31. It is also possible to make the end faces 31a and 31b of the magnet 31 project toward the guide surface side (the lid 12 side) than the facing surfaces 32a1 and 32a2 of the auxiliary member 32.

  Further, according to the above embodiment, the aspect in which the auxiliary member 32 is a weight is shown, but as another example of the auxiliary member 32, a magnet and a connecting member for connecting the magnet, and other members It is possible.

  As mentioned above, although the embodiment of the present invention has been described in detail, the specific configuration is not limited to these embodiments, and even if there is a design change or the like within the scope of the present invention. Included in the invention. In addition, the respective embodiments described above can be combined with each other by utilizing the techniques of each other unless there is a contradiction or a problem in particular in the purpose, the configuration, and the like.

1, 1 ': electromagnetic actuator 20: coil 21: guide surface 30: mover 31: magnet 31a, 31b: end surface 32: auxiliary member (cone)
32a, 32a ': mating parts 32a1, 32a2: facing surfaces 40: biasing member 50: magnetic fluid d: level difference s1, s2: gap

Claims (5)

A guide surface, a mover that vibrates along the guide surface, a magnetic fluid interposed between the mover and the guide surface, and a coil that vibrates the mover by a magnetic action.
The mover integrally includes a magnet and an auxiliary member so as to be aligned in a direction along the guide surface;
The auxiliary member has an opposing surface that approaches or contacts the end surface of the magnet in the direction along the guide surface,
An electromagnetic actuator characterized in that the magnet projects the end face toward the guide surface side relative to the opposing surface.   The electromagnetic actuator according to claim 1, wherein both ends of the magnet in the vibration direction are the end surfaces.   The electromagnetic actuator according to claim 1, wherein the guide surface is provided on the coil.   The said auxiliary member has the to-be-fitted part fitted to the circumferential side surface of the said magnet, The said magnet is made to project from the said to-be-fitted part to the guide surface side. The electromagnetic actuator according to item 1. The electronic device provided with the electromagnetic actuator in any one of Claims 1-4.

Images