This application is based upon and claims the benefit of priority of the prior Japanese Patent Application No. 2013-138394 filed on Jul. 1, 2013, the entire contents of which are incorporated herein by reference.
A certain aspect of the embodiments is related to an electromagnetic relay, e.g. an electromagnetic relay that includes a pressing member which presses an elastic body biasing a movable contact.
For example, in Japanese Laid-open Patent Publication No. 2001-126601, an electromagnetic relay includes a yoke which can change a magnetic pole by an electromagnet, and an armature magnetized with a permanent magnet. The polarity of the electromagnet is changed, so that the magnetic pole of the yoke is changed. Thereby, the armature comes in contact with the yoke or detaches from the yoke. The movable contact is biased by an elastic body, and the pressing member presses the elastic body according to the operation of the armature. Thereby, the fixed contact comes in contact with the movable contact or detaches from the movable contact. Therefore, this function as the electromagnetic relay.
According to an aspect of the present invention, there is provided an electromagnetic relay, including: a first movable contact that comes in contact with a first fixed contact; a second movable contact that comes in contact with a second fixed contact; a first elastic body that biases the first movable contact; a second elastic body that biases the second movable contact; a pressing member that presses the first elastic body and contacts the first movable contact to the first fixed contact, presses the second elastic body and contacts the second movable contact to the second fixed contact; wherein the pressing member contacts the second movable contact to the second fixed contact before contacting the first movable contact to the first fixed contact.
The object and advantages of the invention will be realized and attained by means of the elements and combinations particularly pointed out in the claims.
It is to be understood that both the foregoing general description and the following detailed description are exemplary and explanatory and are not restrictive of the invention, as claimed.
In Japanese Laid-open Patent Publication No. 2001-126601, when the fixed contact comes in contact with the movable contact or detaches from the movable contact, a bounce by the collision of the fixed contact and the movable contact occurs. When an energizing current is large, arc discharge occurs in the case of the bounce. Contact welding occurs by the heat of the arc discharge, and the contacts become defect. Rolling of one contact exists as this measure. However, when the energizing current is large, a cross-sectional area of a spring of the contact is enlarged, so that the bending of the spring for leading the rolling cannot be secured adequately.
A description will now be given of embodiment of the present invention with reference to the drawings.
In the electromagnet 20, a coil wire 22 is wound around a bobbin 24. Terminals 26 are electrically connected to the coil wire 22. A pair of yokes 10 is magnetically connected to both sides of the electromagnet 20. The magnetic poles of respective ends of a pair of yokes 10 are opposite to each other. When the direction of a current which flows into the coil wire 22 is changed, the polarity of the electromagnet 20 is reversed. Thus, the magnetic poles of the yokes 10 can be changed with the electromagnet. The armatures 12 are magnetized with a permanent magnet, and come in contact with the yokes 10 or detach from the yokes 10 by the magnetic poles of the yokes 10. A part of the armatures 12 and the permanent magnet (not shown) are fixed by the armature cover 13.
The first movable contact 30a is electrically connected to the movable terminal 34 via the spring 32a (a first elastic body). The second movable contact 30b is electrically connected to the movable terminal 34 via the spring 32b (a second elastic body). The springs 32a and 32b are fixed to the movable terminal 34 with a fixed portion 39. The first fixed contact 40a and the second fixed contact 40b are electrically connected to the fixed terminal 42. When the first movable contact 30a comes in contact with the first fixed contact 40a, and the second movable contact 30b comes in contact with the second fixed contact 40b, the movable terminal 34 is electrically connected to the fixed terminal 42. When the first movable contact 30a detaches from the first fixed contact 40a, and the second movable contact 30b detaches from the second fixed contact 40b, the movable terminal 34 and the fixed terminal 42 become non-conductive electrically.
The first movable contact 30a is biased by the springs 32a and 36a so as to detach from the first fixed contact 40a. As illustrated in
The second movable contact 30b is biased by the springs 32b and 36b so as to detach from the second fixed contact 40b. As illustrated in
The connection member 14 connects the first contact pressing portion 16a, the second contact pressing portion 16b, the first detachment pressing portion 18a and the second detachment pressing portion 18b with the armature cover 13.
A pressing member is formed at the tip of the connection member 14. The pressing member includes the first contact pressing portion 16a, the second contact pressing portion 16b, the first detachment pressing portion 18a and the second detachment pressing portion 18b. A step is formed between the second contact pressing portion 16b and the first contact pressing portion 16a so that the second contact pressing portion 16b projects in the −Y direction compared with the first contact pressing portion 16a. Thereby, a distance from the spring 36a to the first contact pressing portion 16a becomes longer than a distance from the spring 36b to the second contact pressing portion 16b. A step is formed between the first detachment pressing portion 18a and the second detachment pressing portion 18b so that the first detachment pressing portion 18a projects in the +Y direction, compared with the second detachment pressing portion 18b. Thereby, a distance from the spring 32a to the first detachment pressing portion 18a becomes shorter than a distance from the spring 32b to the second detachment pressing portion 18b.
The armature cover 13, the connection member 14, and the pressing portions 16a, 16b, 18a and 18b are integrally formed with resin, for example.
The springs 32a, 32b, 36a and 36b are not integrally formed with the armature cover 13, the connection member 14, and the pressing portions 16a, 16b, 18a and 18b, and can be separated from the pressing portions 16a, 16b, 18a and 18b.
By pressing the first elastic body (the springs 32a and 32b), the pressing portions 16a and 16b cause the first movable contact 30a and 30b to contact with the first fixed contact 40a and 40b. By pressing the second elastic body (the springs 36a and 36b), the pressing portions 18a and 18b cause the second movable contact 30a and 30b to detach from the second fixed contact 40a and 40b.
The armature rotary-shaft-projection 53 is not arranged on a central line of the yokes 10, and is arranged on the outside of the pair of armatures 12. Therefore, a volume of the permanent magnet 17 located between the armatures 12 can be secured adequately, and a relay excellent in shock resistance can be offered.
Moreover, the first movable contact 30a is smaller than the second movable contact 30b, as illustrated in
Moreover, the pressing portions 18a and 18b detach the second movable contact 30b from the second fixed contact 40b (
Moreover, the first contact pressing portion 16a presses the first elastic body to contact the first movable contact 30a to the first fixed contact 40a (
Moreover, the first detachment pressing portion 18a (i.e., a first detachment portion) presses the first elastic body to detach the first movable contact 30a from the first fixed contact 40a (
Moreover, a width W1a of the first elastic body between the first movable contact 30a and a fixed portion 86 of the first elastic body is wider than a width W1b of the second elastic body between the second movable contact 30b and the fixed portion 86 of the second elastic body, as illustrated in
Moreover, a width W2a of the first elastic body of a portion (i.e., a position) with which the first contact pressing portion 16a comes in contact is narrower than a width W2b of the second elastic body of a portion (i.e., a position) with which the second contact pressing portion 16b comes in contact, as illustrated in
Moreover, the springs 32a and 36a include curved portions 60a and 62a which curve into a V-shape between the first movable contact 30a and the fixed portion 86, as illustrated in
Moreover, the springs 32a and 36a include an opening 64 in the curved portions 60a and 62a. Thereby, bending of the elastic body can be secured.
Moreover, the first elastic body includes two springs which are the spring 36a (i.e., a third elastic body) and the spring 32a (i.e., a fourth elastic body) arranged so as to overlap with the spring 36a, as illustrated in
Moreover, the springs 32a and 32b serve as current pathways. Therefore, material with high conductivity is used for the springs 32a and 32b. On the contrary, since the springs 36a and 36b are formed independently from the springs 32a and 32b, material with high spring characteristic can be used for the springs 36a and 36b. A copper alloy, such as a Cu—Cr based alloy with high conductivity or a Cu—Fe based alloy with high conductivity, can be used as the springs 32a and 32b. Phosphor bronze, such as a Cu—Sn based alloy with high spring characteristic, can be used as the springs 36a and 36b. Moreover, when a Cu—Cr—Zr—Si based alloy with high conductivity and high spring characteristic is used as the springs 36a and 36b, the rise in temperature of the electromagnetic relay when a current is supplied can be controlled. Moreover, the resistance characteristic of the spring by repetition operation can be improved. Here, the Cu—Cr—Zr—Si based alloy may be used for the springs 32a and 32b.
Moreover, since the movable terminal 34 and the fixed terminal 42 are arranged as illustrated in
That is, the current direction 70 which flows into the first movable contact 30a and the second movable contact 30b from the movable terminal 34, and the current direction 72 which flows out from the first fixed contact 40a and the second fixed contact 40b to the fixed terminal 42 are the same direction. Alternatively, a current direction (i.e., a direction opposite to the direction 70) which flows out from the first movable contact 30a and the second movable contact 30b to the movable terminal 34, and a current direction (i.e., a direction opposite to the direction 72) which flows into the first fixed contact 40a and the second fixed contact 40b from the fixed terminal 42 are the same direction.
When a large current (for example, several thousand amperes) flows by the malfunction of a system, and the current directions 70 and 72 are opposite directions mutually, an electromagnetic repulsive force arises between the contacts by Ampere's corkscrew law. Therefore, a force acts on a direction where the movable contact which is in a contact state detaches, the arc discharge occurs when the movable contact detaches, and hence the contact welding may arise. However, according to the first embodiment, since the current directions 70 and 72 are the same directions, the detachment of the movable contact can be controlled even when the large current flows.
As illustrated in
When slight contact welding occurs, the rotary shaft of the armature cover 13 inclines and the rotation is inhibited. Thereby, it becomes difficult to detach the contacts from each other even when the slight welding is essentially detachable. According to the first embodiment, the armature rotation bearing 80 and the armature rotary-shaft-projection 53 are formed on the armature cover 13, as illustrated in
Moreover, a distance from the springs 32a and 32b to the detachment pressing portions 18a and 18b when the detachment pressing portions 18a and 18b are detached from the springs 32a and 32b is longer than a distance from the springs 32a and 32b to the contact pressing portion 16a and 16b when the contact pressing portion 16a and 16b are detached from the springs 32a and 32b. Thereby, when the detachment pressing portions 18a and 18b come in contact with the springs 32a and 32b, the detachment pressing portions 18a and 18b having a speed collide with the springs 32a and 32b. This collision can tear off the movable contact. Therefore, welding failure of the contacts can be more controlled.
All examples and conditional language recited herein are intended for pedagogical purposes to aid the reader in understanding the invention and the concepts contributed by the inventor to furthering the art, and are to be construed as being without limitation to such specifically recited examples and conditions, nor does the organization of such examples in the specification relate to a showing of the superiority and inferiority of the invention. Although the embodiments of the present invention have been described in detail, it should be understood that the various change, substitutions, and alterations could be made hereto without departing from the spirit and scope of the invention.
Number | Date | Country | Kind |
---|---|---|---|
2013-138394 | Jul 2013 | JP | national |
Number | Name | Date | Kind |
---|---|---|---|
3993971 | Ono et al. | Nov 1976 | A |
4625191 | Oberndorfer et al. | Nov 1986 | A |
5719541 | Mader | Feb 1998 | A |
5994987 | Passow | Nov 1999 | A |
6020801 | Passow | Feb 2000 | A |
6046660 | Gruner | Apr 2000 | A |
6788176 | Schmelz | Sep 2004 | B2 |
7477119 | Wu | Jan 2009 | B2 |
8203403 | Moeller et al. | Jun 2012 | B2 |
8222981 | Zarbock et al. | Jul 2012 | B1 |
8222982 | Sullivan et al. | Jul 2012 | B2 |
8237523 | Helmreich | Aug 2012 | B2 |
8564386 | Moeller et al. | Oct 2013 | B2 |
20040080388 | Schmelz | Apr 2004 | A1 |
20090033446 | Gruner et al. | Feb 2009 | A1 |
20090033447 | Gruner et al. | Feb 2009 | A1 |
20130278362 | Iwamoto et al. | Oct 2013 | A1 |
Number | Date | Country |
---|---|---|
1 175 807 | Aug 1964 | DE |
198 31 658 | Feb 2000 | DE |
2 551 868 | Jan 2013 | EP |
6-76717 | Mar 1994 | JP |
2001-126601 | May 2001 | JP |
2013-30310 | Feb 2013 | JP |
2013-222699 | Oct 2013 | JP |
Entry |
---|
Patent Abstracts of Japan, Publication No. 2001-126601, Published May 11, 2001. |
Patent Abstracts of Japan, Publication No. 2013-030310, Published Feb. 7, 2013. |
Patent Abstracts of Japan, Publication No. 2013-222699, Published Oct. 28, 2013. |
Patent Abstracts of Japan, Publication No. 06-076717, Published Mar. 18, 1994. |
Espacenet Abstract, Publication No. 19831658, Published Feb. 3, 2000. |
European Search Report of Application No. 14163449.3 mailed Dec. 10, 2014. |
Number | Date | Country | |
---|---|---|---|
20150002248 A1 | Jan 2015 | US |