JPH05135645A - Reed switch - Google Patents

Abstract

PURPOSE:To prevent production of oxides on the contact surfaces of the contact portions, or occurrence of defective contacts due to entry of insulative fine particles, and thereby obtain a stable contact resistance value. CONSTITUTION:Contact surfaces 17a and 19a of opposed reed switches 21 are formed at an inclination having an angle with respect to an imaginary plane (s) orthogonally intersecting a direction (d) in which the contact surfaces 17a, 19a are moved toward each other, or are moved away from each other. At the time of contacting or parting of the contacts, the contact surfaces 17a, 19a are slid against each other so as to scrape oxidized formations and the like.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a contact structure for a reed switch.

[0002]

2. Description of the Related Art A reed switch is one that opens and closes a switch contact by a magnetic field. FIG. 6 is an explanatory diagram showing the structure of a conventional reed switch. Inside the sealed glass tube 1, a pair of lead pieces 3 made of a magnetic material,
5 are inserted from both sides to form a pair of lead pieces 3,
The tips of 5 are parallel to each other in the glass tube 1 with a gap therebetween. The facing pieces serve as the contact portions 7 and 9 of the reed switch. Glass tube 1 provided with contact points 7 and 9
An inert gas G is enclosed in the interior for the purpose of preventing oxide formation due to discharge when the switch contacts are opened and closed.

7 (a) and 7 (b) are enlarged views showing contact points. The conventional reed switch 11 configured as described above
When a magnetic field is formed by the coil or the magnet, the N pole or the S pole is induced at the tips of the lead pieces 3 and 5, and the opposite contact portions 7 and 9 have different polarities.
As shown in FIG. 7B, the parallel state is approached by the magnetic attraction force and brought into the contact state. Then, when the magnetic field is removed, the magnetic attraction force disappears, and the contact points 7 and 9 are separated and rebounded by the elastic force of the entire lead pieces 3 and 5, and are restored to the facing state again. In this manner, in the conventional reed switch 11, the tips of the reed pieces 3 and 5 come into contact with each other and move away from each other, so that the contact portions 7 and 9 are opened and closed.

[0004]

However, in the conventional reed switch 11, oxide is generated and adhered to the contact surfaces of the contact portions 7 and 9 in spite of measures such as enclosing the inert gas G. Or, oxides or fine particles having insulating properties may enter from the outside of the contact portions 7, 9 to the contact surface side. In such a case, contact failure of the contact occurs and the contact resistance value increases, There was a risk of causing poor continuity.

The present invention has been made in view of the above situation, and prevents generation of oxide on the contact surface of the contact portion and occurrence of contact failure due to mixing of insulating fine particles from the outside of the contact portion, and stable contact resistance value. It is an object of the present invention to provide a reed switch that can achieve the above, and thereby to stabilize the quality and improve the yield.

[0006]

The structure of a reed switch according to the present invention for achieving the above object is a reed switch having opposing contact surfaces which are in contact with each other by a magnetic attraction force and which can abut. Is formed by an inclined surface having an angle with respect to an imaginary plane orthogonal to the approaching and separating recoil direction,
It is characterized in that the contact surfaces of each other slide when the contacts are opened and closed.

[0007]

When a magnetic field is formed, the tips of the lead pieces are attracted to each other, and the contact surfaces come into contact with each other at an inclined surface having an angle with respect to a virtual surface orthogonal to the approaching / separating direction, and are stable from the start of contact. In a minute time to the contact position, the contact surfaces slide in the inclined direction for a minute distance, and oxides and the like generated on the contact surface are scraped off. Further, when the magnetic field is removed when the contact portion is restored, the magnetic attraction force disappears, and the contact surfaces are slid apart from each other, oxides and the like are scraped off, and the contact surface is always in a clean state as in the case of contact.

[0008]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Preferred embodiments of the reed switch according to the present invention will be described in detail below with reference to the drawings. FIG. 1 is an explanatory diagram showing the structure of a reed switch according to the present invention. Inside the sealed glass tube 1, a pair of lead pieces 13 and 15 made of a magnetic material are inserted from both sides, and the tips of the pair of lead pieces 13 and 15 are separated from each other in the glass tube 1. Parallel to each other. As in the conventional case, the glass tube 1 is filled with an inert gas G for the purpose of preventing oxide formation due to discharge when the switch contacts are opened and closed.

Opposing surface 1 of each of lead pieces 13 and 15
Protrusions 17 and 19 are provided on the protrusions 3a and 15a, respectively.
Contact surfaces 17a and 19a of the contact portions are formed on 7 and 19, respectively. The contact surfaces 17a and 19a are the contact surfaces 17
a, 19a is a virtual surface s orthogonal to the approaching / retracting direction d of the two
Are inclined surfaces having a certain angle with respect to each other, and are parallel to each other and face each other. Therefore, the lead pieces 13, 1
When the tips of the five members try to contact each other, the contact surfaces 17a, 1
9a relatively moves relatively along the inclination direction. That is, when the contact portions come into contact with each other, the contact surfaces 17a and 19a slide (rub) in the inclined direction. Glass tube 1, lead pieces 13, 15, protrusions 17, 1
The reed switch 21 according to the present embodiment is composed of the contact surfaces 17a and 19a.

2A, 2B and 2C are explanatory views showing the contact process of the reed switch. In the reed switch 21 configured as above, when a magnetic field of a coil or a magnet is formed, the tips of the lead pieces 13 and 15 are attracted to each other, and the contact surfaces 17a and 19a tend to contact each other (see FIG. See b)). At this time, the contact surfaces 17a and 19a slide in the tilt direction t from the start of contact to the stable contact position (see FIG. 2C). Contact surface 17
By the sliding of a and 19a, the oxide generated on the contact surface or the insulating fine particles adhering to and adhering from the outside of the contact portion are scraped off. Also, at the time of restoration,
When the magnetic field is removed, the magnetic attraction force disappears and the lead piece 1
Although the tip ends of 3 and 15 move away from each other, the contact surfaces 17a and 19a also slide apart from each other at this time, and oxides and the like are scraped off at the time of contact, and the contact portion is always clean. Will be maintained.

Next, another embodiment having different contact point shapes will be described with reference to FIGS. FIG. 3 is an explanatory view showing another embodiment in which a protrusion having a convex curved surface is formed. Lead piece 2
Protrusions 27 and 29 are provided on the facing surfaces 23a and 25a of the protrusions 3 and 25, respectively, and the tip ends of the protrusions 27 and 29 have convex curved surfaces. The outer peripheral surfaces of the protrusions 27 and 29 having the convex curved surfaces are contact surfaces 27a and 29a.
Therefore, in addition to the same effect as described above,
At the start of contact, the contact surfaces 27a and 29a are in line contact with each other, and when the contact surfaces 27a and 29a are slid on each other, the oxide or the like can be scraped off locally with a large force.

FIG. 4 is an explanatory view showing another embodiment in which a stopper is formed at the end of the inclined contact surface. Lead piece 31,
The contact surface 31a, which is an inclined surface facing the tip of 33,
33 a is formed, and a stopper 35 protruding in the longitudinal direction of the lead piece 33 is formed at the tip of one lead piece 33. In this embodiment, at the start of contact, the contact surfaces 31a and 33a slide as described above, so that oxides and the like can be scraped off, and the stopper 35 and the side surface of the lead piece 33 come into contact with each other at the stable contact position. A large area can be secured.

FIG. 5 is an explanatory view showing another embodiment in which the contact portion is formed by an uneven curved surface. A concave curved contact surface 37a is formed on the tip surface of the lead piece 37, and a convex curved contact surface 39a facing the contact surface 37a is formed on the tip of the lead piece 39.
Are formed. In this embodiment, at the start of contact, the contact surfaces 37a and 39a slide by the line contact as described above, the contact surfaces 37a and 39a slide locally with a large frictional force, and at the stable contact position, The contact surface 39a is brought into contact with the contact surface 37a, and a reliable contact state can be achieved.

[0014]

As described above in detail, in the reed switch according to the present invention, the contact surface is formed by the inclined surface, and the contact surfaces slide with each other when the contacts are opened and closed. Since the oxides and the like can be scraped off and the contact surface can be maintained in a clean state, a stable contact resistance value can be obtained at all times. As a result, the quality can be stabilized and the yield can be improved.

[Brief description of drawings]

FIG. 1 is an explanatory diagram showing a structure of a reed switch according to the present invention.

FIG. 2 is an explanatory diagram showing a contact process of a reed switch.

FIG. 3 is an explanatory diagram showing another embodiment in which a protrusion having a convex curved surface is formed.

FIG. 4 is an explanatory view showing another embodiment in which a stopper is formed at the end of the inclined contact surface.

FIG. 5 is an explanatory view showing another embodiment in which a contact portion is formed with an uneven curved surface.

FIG. 6 is an explanatory diagram showing a structure of a conventional reed switch.

FIG. 7 is an enlarged view showing a contact portion of a conventional reed switch.

[Explanation of symbols]

 17a, 19a contact surface 21 reed switch d approaching / separating reaction direction s virtual surface

Claims (1)

[Claims] 1. A reed switch contacting with a magnetic attraction force, wherein a contact surface of a contact portion is formed by an inclined surface having an angle with respect to an imaginary surface orthogonal to the approaching / separating reaction direction of each other. Reed switch.