JPH0125176B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a rotary-operated microswitch, and more particularly to a low-torque rotary-operated microswitch that operates with extremely light force and is used for coin detection, paper detection, and the like.

As this type of low-torque rotationally operated microswitch, a combination of a magnet and a magneto-electric conversion element such as a Hall IC or a reed switch has been known. In other words, a magnetoelectric transducer is fixed inside the case, a magnet is fixed to the inside of the case of a rotating shaft that is rotatably mounted through the case wall, and an actuator lever is attached to the outside of this rotating shaft. Therefore, when the rotating shaft is rotated,
The magnet rotates integrally with this to apply a change in the magnetic field to the magnetoelectric conversion element, and the magnetoelectric conversion element operates in response to this change. Conventional switches of this type use an elastic member such as a torsion coil spring to provide a return torque to return the rotating shaft to a predetermined free position. In this type of device that uses a spring to apply return torque, when the rotary shaft is rotated from the free position to the operating position, the operating torque increases in proportion to the rotation angle, which is extremely The drawback is that it is difficult to obtain small, uniform, and stable operating torque characteristics. For this reason, there were problems such as coin jamming during coin detection and the inability to use it for detecting extremely thin paper.

This invention was made in view of the above-mentioned conventional problems, and its purpose is to provide an extremely small, uniform, and stable operating characteristic without using any elastic materials such as torsion coil springs. It is an object of the present invention to provide a rotary operation type microswitch which can produce a sudden change in the magnetic field with the rotational displacement of a magnet, and can obtain good switching characteristics.

In order to achieve the above object, the present invention has an attraction plate made of a ferromagnetic material fixed inside the case facing the magnet attached to the rotating shaft, and acts between the attraction plate and the magnet. A return torque is obtained to return and rotate the magnet and the rotating shaft to a predetermined free position by magnetic attraction, and when the rotating shaft and the magnet are rotationally displaced from the free position, the displacement A sudden change in the magnetic field is caused by this, and a magnetoelectric transducer is fixedly installed at a position where it operates in response to the change in the magnetic field.

Hereinafter, embodiments of the present invention will be described in detail based on the drawings.

Fig. 1 is a perspective view showing the external appearance of the microswitch according to the present invention, Fig. 2 is a sectional view taken along the - line, and Figs. 3 and 4 are plan views showing the inside after disassembling it into the lower case side and the upper case side. It is. As shown in each figure, the case of this microswitch is divided into two parts, an upper case 1 and a lower case 2.The upper case 1 and the lower case 2 are fitted together with their recessed sides facing each other. Both are fixed with rivets 3. A bearing hole 4 is formed in the upper case 1 and passes through the wall thereof, and a rotary shaft 5 is rotatably mounted in the bearing hole 4. A notch 7 is formed in the flange 6 of the outer protrusion of the rotating shaft 5, and a stopper pin 7 formed on the upper case 1 engages with this notch, and the rotational movement of the rotating shaft 5 is controlled within a predetermined angular range. are becoming regulated.

Further, inside the upper case 1, a permanent magnet 10 held by a holder 9 is fixed to the rotating shaft 5. This magnet 10 is a bar-shaped magnet that is long in the direction of both poles, and is arranged so that the directions of both poles are orthogonal to the axis of the rotating shaft 5. Furthermore, the rotating shaft 5 and the magnet 10 fixed thereto are in the illustrated free position.
In the OP state, the direction of both poles of the magnet 10 is arranged to be orthogonal to the longitudinal direction of the upper case 1.

Two terminal pieces 11 and 12 are attached to the lower case 2 side so as to pass through the inside and outside of the case, and a reed switch 13 is soldered to the inner ends of both terminal pieces 11 and 12 so as to straddle them. There is. This reed switch 13 is arranged parallel to the longitudinal direction of the lower case 2, and therefore, as described above, the direction of both poles of the magnet 10 in the free position OP and the longitudinal direction of the reed switch 13 are perpendicular to each other. It's becoming like that. In addition, an attraction plate 14 made of a band-shaped ferromagnetic material and having a width slightly larger than the width of the magnet 10 is fixed to the lower case 2 so as to face the magnet 10 in the free position OP. This suction plate 14 is curved so as to go around the back of the reed switch 13 so as not to interfere with the reed switch 13.
Both end portions of the suction plate 14 are arranged to face the poles N and S of the magnet 10 in the free position OP in close proximity.

In the above configuration, the rotating shaft 5 and the magnet 10
is in the free position OP, both poles N and S of the magnet 10
are opposed to both end portions of the attraction plate 14 in close proximity to each other, most of the magnetic flux of the magnet 10 is transferred to the attraction plate 14.
will pass through. In other words, the attraction force acting between the magnet 10 and the attraction plate 14 causes the magnet 10 to
And the rotating shaft 5 is positioned so as to come to the free position OP. In this way, the free position OP
The direction of both poles of the magnet 10 is the reed switch 13
Since it is perpendicular to the reed switch 13, not only does the reed switch 13 not operate, but most of the magnetic flux of the magnet 10 in the free position OP passes through the attraction plate 14, so almost no magnetic field acts on the reed switch 13. .

From the above state, when the rotating shaft 5 is rotationally displaced toward the maximum operating position TTP as shown by arrow a using an actuator lever or the like attached to the rotating shaft 5, the magnet 10 is rotationally displaced together with the rotating shaft 5. magnet 10
The two poles N and S gradually move away from both ends of the attraction plate 14, and the magnetic flux passing through the attraction plate 14 gradually decreases. At the same time, the direction of both poles of the magnet 10 gradually approaches the longitudinal direction of the reed switch 13, so when the magnet 10 is rotated to a certain extent, the magnetic flux passing through the attraction plate 14 is The magnetic flux that acts on the reed switch 13 suddenly decreases, and conversely, the magnetic flux that acts on the reed switch 13 suddenly increases. In response to this, the reed switch 13 operates. The operating torque of the rotating shaft 5 required to operate the reed switch 13 in this way is a force that resists the magnetic attraction force between the magnet 10 and the attraction plate 14, and this attraction force causes the magnet 10 to move to the free position OP. At some point, the maximum
As the magnet 10 is rotated and displaced, it gradually becomes smaller. For this reason, unlike those using conventional springs, where the operating torque required to rotationally displace the rotating shaft 5 gradually increases,
Stable operation with extremely small operating torque can be achieved. Furthermore, when the operating torque applied to the rotating shaft 5 is removed, the rotating shaft 5 and the magnet 10 return to the original free position OP due to the magnetic attraction force acting between the magnet 10 and the attraction plate 14. .

Although the reed switch 13 is used as the magnetoelectric conversion element in the above embodiment, the present invention is not limited to this, and a magnetoelectric conversion element such as a Hall IC may also be used.

As explained in detail above, the rotary operation type micro switch according to the present invention does not use any elastic material such as a torsion coil spring as in the past, but uses the attractive force of a magnet to return torque to the rotating shaft. Since the return force is obtained, uniformity of operating torque can be obtained, and the torque is also extremely small, so that it can sufficiently cope with minute rotational force, and extremely uniform and stable operating characteristics can be obtained.

Furthermore, since a rapid change in the magnetic field can be obtained with the rotational displacement of the magnet, the switching operation characteristics are also improved, and an extremely good rotary operation type microswitch can be obtained.

[Brief explanation of drawings]

Fig. 1 is a perspective view showing the external appearance of a rotary operation type micro switch according to the present invention, Fig. 2 is a cross-sectional view taken along the - line, and Figs. FIG. 1... Upper case, 2... Lower case, 4... Bearing hole, 5... Rotating shaft, 10... Magnet, 13... Reed switch, 14... Suction plate, OP... Free position,
TTP...Maximum operating position.

Claims (1)

[Claims] 1. A rotating shaft rotatably mounted in a bearing hole formed through the case wall, a magnet fixed to the rotating shaft inside the case and disposed with both poles perpendicular to the rotating shaft, and both end portions. is very close to both poles of the magnet, is curved toward the opposite side of the magnet, and is fixed inside the case, and the magnet and the rotation axis are fixed by the magnetic attraction force acting between the magnet and the magnet. a suction plate made of a ferromagnetic material that rotates the magnet back to its free position; A rotary operating type microswitch comprising a magneto-electric transducer fixed inside a case so as to operate in response to changes in the generated magnetic field.