JPS5911391Y2 - Non-contact micro switch - Google Patents

Description

[Detailed Description of the Invention] This invention relates to a non-contact microswitch using a Hall IC, and particularly relates to an improvement in the mounting structure of the Hall IC to a case.

Conventionally, non-contact microswitches using Hall ICs and operated by applying changes in magnetic flux have been widely used.

There are push-button operated types and rotary types, in which a magnet moves in conjunction with an actuator relative to a Hall IC fixed in a case, changing the magnetic flux.

FIG. 1 shows an example of a rotary microswitch, in which a magnet 4 attached to a cover 3 moves around a rotating shaft 5 to change the front surface of a Hall IC 2 fixed to a case 1. It gives

6 is a magnetic shielding plate that blocks external magnetic flux, and the above Hall IC 2
was attached to a recess formed in the case 1 together with the magnetic shielding plate 6 using an adhesive.

However, this fixing method using adhesive has the disadvantage that the assembly work is complicated and work efficiency is low, and the Hall IC is likely to fall off due to aging of the adhesive, especially at high temperatures.

In addition, since the above-mentioned Hall ICs have slightly different external shapes depending on specifications such as operating voltage, it is difficult to accurately position them using adhesive fixing methods, which has the disadvantage of causing variations in the operating position of the actuator. Ta.

This idea was made in view of the above drawbacks, and the magnetic shielding plate that protects the Hall IC is also used as a fixture, and its elasticity holds the Hall IC and fixes the magnetic shielding plate itself in the case. This is what I did.

Hereinafter, one embodiment of this invention will be described in detail based on the drawings.

Figures 2 and 3 show a rotary non-contact microswitch according to this invention, which can be roughly divided into a case 12 to which fixed parts are attached around the Hall IC 11, and a cover to which movable parts are attached to the magnet 13. 14, and both are detachably engaged with each other.

The Hall ICII has a package several mm square, and three lead wires are led out from one side of the package.

15, which will be described later, is a magnetic shielding plate that fixes the hole ICll and prevents the influence of external magnetic fields, and its bottom 15C is inserted into the recess between the walls 16, 16 formed approximately in the center of the case 12. It is press-fitted tightly to the bottom of the

Reference numeral 17 denotes a bearing portion 18 formed continuously with the wall portion 16,
18, 18 are terminals connected to the lead wires of the Hall IC II, and depending on specifications, a resistor or the like may be installed between the terminals 18... and the Hall IC.

The cover 14 is formed with a bearing hole into which a bearing 19 is pressed, and a rotary shaft 21 is attached to the case 1 and has a metal pipe 20 fixed to its base that slides smoothly on the bearing 19.
It is rotatably supported by a bearing part 17 of No. 2 and this bearing 19.

A rotating arm 22 that rotates together with the rotating shaft 21 is fixed to the tip of the rotating shaft 21, and a magnetic plate 23 is embedded in the tip of the rotating arm 22.
The magnet 13 is attached so as to be attracted to the magnetic plate 23.

On the other hand, the head 21a of the rotating shaft 21 is shaped like a disk and has a fan-shaped notch in a part thereof, and this notch engages with a projection (not shown) of the case 12. The rotating shaft 21 is rotatable only by a predetermined angle, and a torsion coil spring 24 for returning rotation is secured at both ends to the base of the rotating arm 22 and a projection (not shown) in the case 12.
is fitted, and the rotating shaft 21 is biased in one rotational direction.

Further, a wire-shaped actuator lever 25 is removably attached within the groove of the head 21a.

FIG. 4 shows the magnetic shielding plate 15 to which the Hall IC 11 is attached.
The magnetic shielding plate 15 is made of a magnetic material such as mild steel that has some elasticity, and is bent into a U-shaped cross section with a slightly enlarged tip.
C is attached closely to the bottom surface of the switch case 12, and is held between the wall portions 16 by the elasticity of its substantially parallel bent portions 15a, 15a.

On the other hand, tongue pieces 15b, 15b are cut out approximately at the center of each of the bent portions 15a, 15a, and are slightly bent inward, and their elasticity allows the hole C1
Hold 1.

Therefore, the hole C11 is held by the magnetic shielding plate 15 simply by being pushed into it, and the magnetic shielding plate 15 is fixed to the case 12 by simply being press-fitted between the walls 16, 16.

In addition, even if the outer shape of the hole C11 is different, the center can be accurately positioned, and if necessary, the tongue pieces 15b, 15b can be replaced with a magnetic shielding plate 15 whose shape is changed according to the dimensions of the hole IC11. Hole of each specification ■
C11 can be installed as is.

In order to further ensure the engagement between the magnetic shielding plate 15 and the walls 16, 16, as shown in FIG.
may be extended so that the edges of the bent portions 15a, 15a bite into them, and it is even more preferable to form slight protrusions 16a, 16a on the tops of the bent portions 15a, 15a, as shown in FIG. 6, to ensure secure fixation.

Next, I will briefly explain the operation of this microswitch.
First, when the actuator lever 25 is not operated, the rotary arm 22 is biased by the torsion coil spring 24 and is in position A shown by the imaginary line in FIG.

At this time, the magnetic field of the magnet 13 has almost no effect on the hole C11, so that no predetermined detection signal is emitted from the hole C11.

On the other hand, twist the actuator lever 25 to release the coil spring 2.
4, the rotary arm 22 reaches position B, and the magnetic flux passing through the hole C11 increases, so that a predetermined detection signal is emitted from the Hall IC11.

As is clear from the above explanation, the non-contact microswitch according to this invention is made of a magnetic plate with some elasticity, which is bent into a U-shaped cross section, and the parallel two
A magnetic shielding plate made by cutting and shaping tongues slightly projecting inward on each of the flat surfaces is pressed into the recess formed in the switch case by its elasticity, and the elasticity of the tongues allows the shielding plate to fit into the hole. Since it is designed to support and fix the IC, no adhesive is required to fix the Hall IC.
Not only is the assembly work simple, but the Hall IC does not fall off due to adhesive deterioration.

Furthermore, since the positioning is accurate, there is no variation in operating characteristics, and furthermore, because of the shape that surrounds the entire Hall IC, the magnetic shielding effect is even better.

Further, in the present invention, the bottom part of the magnetic shielding plate having a U-shaped cross section is attached in close contact with the bottom surface of the switch case, and the bottom part of the magnetic shielding plate is configured to cover the bottom surface of the switch case. Because of this, it is not affected by external magnetic fields from the switch case, which stabilizes the operation, and the thickness of the bottom of the switch case can be reduced, allowing the switch as a whole to be made thinner.

Furthermore, since the magnet is attached to the rotary arm that rotates together with the rotary shaft, the rotational position accuracy is improved and a long-life non-contact microswitch can be provided.

[Brief explanation of the drawing]

FIG. 1 is a cutaway sectional view showing an example of a conventional non-contact microswitch, FIG. 2 is a cutaway sectional view showing a non-contact microswitch according to this invention, FIG. 3 is a plan view showing only the case, and FIG. The figure is a perspective view showing a magnetic shielding plate, and FIGS. 5 and 6 are partial views showing other embodiments of this invention.

Claims (1)

[Scope of utility model registration request] While the hole 1C is fixed in the case while being separated from the switch case and the case force bar, the actuator lever is attached to the case force bar via a rotating shaft, and the actuator lever is integrally attached to the rotating shaft. The rotary arm is equipped with a rotating arm having a magnetic plate and a magnet attached to its tip, and is further equipped with a torsion coil spring that biases the rotating shaft in one rotation direction, and moves the magnet in conjunction with the actuator lever. , the above Hall IC
The non-contact microswitch detects the operation of the actuator lever by applying a change in magnetic flux to the actuator lever, which is made of a magnetic plate with some elasticity, which is bent into a U-shaped cross section, and whose parallel two sides are bent. Each of the 1,000 faces is provided with a magnetic shielding plate formed by cutting out a tongue piece that slightly projects inward, and the magnetic shielding plate is placed in a recess formed in the switch case, and its bottom is inserted into the switch case. 1. A non-contact microswitch, characterized in that it is configured so that it is pressed into contact with the bottom surface of a case due to its elasticity, and the Hall IC is supported and fixed by the elasticity of the tongue piece.