Patent Application
20220044897
The present invention relates to an auxiliary contact unit, and particularly relates to a technology that is effectively applied to an auxiliary contact unit attached to a side surface of an electromagnetic contactor.
Attachments (optional components) of an electromagnetic contactor include an auxiliary contact unit. The auxiliary contact unit is an attachment configured to output a signal of an auxiliary contact, which operates in conjunction with opening/closing operation (closing operation and cut-off operation) of the electromagnetic contactor, to an external electronic control circuit or the like, and the types of the auxiliary contact unit include a head-on type in which the auxiliary contact unit is externally attached to the top of the body of the electromagnetic contactor and a side-on type in which the auxiliary contact unit is externally attached to a side surface of the body of the electromagnetic contactor.
A side-on type auxiliary contact unit includes a pair of fixed contact pieces, a movable contact piece arranged in a contactable and separable manner to and from the pair of fixed contact pieces, an auxiliary contact support configured to hold the movable contact piece and move in conjunction with opening/closing operation of the electromagnetic contactor, and a unit case configured to house the pair of fixed contact pieces, the movable contact piece, and the auxiliary contact support in a housing portion formed of a first case member and a second case member.
Note that side-on type auxiliary contact units are disclosed in PTLs 1 and 2.
PTL 1: JP 2011-141963 A
PTL 2: JP 2012-038644 A
The unit case of the auxiliary contact unit is produced by, with joining portions of the respective ones of the first and second case members opposed to each other, pressure-connecting the joining portions of the respective ones of the first and second case members to each other by fastening force exerted by a fastening member, such as a bolt.
However, since the first and second case members are molded products that are formed by injecting insulating resin into a mold, the joining portions of the respective ones thereof are not necessarily flat and there have sometimes been cases where a gap was formed when the joining portions of the respective ones of the first and second case members were opposed to each other. Since such a gap serves as a passing route through which extraneous material, such as dirt and dust, invades the housing portion of the unit case from the outside, and, when insulating extraneous material that has invaded attaches to fixed contacts of the fixed contact pieces or movable contacts of the movable contact pieces, the extraneous material becomes a factor inviting a contact failure, there has been room for improvement from a viewpoint of reliability.
An object of the present invention is to provide a technology capable of increasing reliability of an auxiliary contact unit.
In order to achieve the above-described object, according to an aspect of the present invention, there is provided an auxiliary contact unit including: a pair of fixed contact pieces; a movable contact piece arranged in a contactable and separable manner to and from the pair of fixed contact pieces; an auxiliary contact support configured to hold the movable contact piece and move in conjunction with opening/closing operation of an electromagnetic contactor; and a unit case configured to house the pair of fixed contact pieces, the movable contact piece, and the auxiliary contact support in a housing portion formed with joining portions of respective ones of a first case member and a second case member opposed to each other. The joining portions of the respective ones of the first and second case members are air-tightly joined to each other.
According to the present invention, it is possible to increase reliability of an auxiliary contact unit.
Embodiments of the present invention will now be described in detail with reference to the drawings.
Note that, in all the drawings for descriptions of examples of the present invention, the same reference signs are assigned to constituent components having the same functions and overlapping descriptions thereof will be omitted.
In addition, the respective drawings are schematic and do not necessarily depict actual implementation of the present invention. Further, the embodiments, which will be described below, indicate a device and a method to embody the technical idea of the present invention by way of example, and do not limit the configuration to that described below. That is, the technical idea of the present invention can be subjected to a variety of alterations within the technical scope described in CLAIMS.
In addition, in the following embodiments, it is assumed that, among three directions that are orthogonal to one another in a space, a first direction and a second direction that are orthogonal to each other in an identical plane are the X-direction and the Y-direction, respectively and a third direction that is orthogonal to each of the first direction and the second direction is the Z-direction. The following embodiments will be described, defining a direction in which an auxiliary contact support of an auxiliary contact unit moves to be the Z-direction.
In this first embodiment, an example in which the present invention is applied to a side-on type auxiliary contact unit will be described.
First, an attachment position of an auxiliary contact unit 1 according to the first embodiment of the present invention will be described with reference to
As illustrated in
Next, a configuration of the electromagnetic contactor 50 will be described with reference to
As illustrated in
As illustrated in
Each contact piece of each of the pairs of fixed contact pieces 61 and 62 extends in the X-direction and has a fixed contact formed on one end side and an external terminal portion formed on the other end side. Each of the pairs of fixed contact pieces 61 and 62 are fixed to the body case 51 with the one end sides of the respective ones thereof opposed to each other and separated from each other in the X-direction.
Each of the movable contact pieces 63 extends in the X-direction and has movable contacts respectively formed on one end side and the other end side. The movable contact on the one end side of the movable contact piece 63 and the fixed contact of the one fixed contact piece 61 are arranged in such a manner as to face each other. The movable contact on the other end side of the movable contact piece 63 and the fixed contact of the other fixed contact piece 62 are arranged in such a manner as to face each other. The movable contact pieces 63 are held by the movable contact support 64. Each of the pairs of fixed contact pieces 61 and 62 and a corresponding movable contact piece 63 constitute a contact portion, and three contact portions of this type are arranged in line in the Y-direction in a corresponding manner to the three-phase AC circuit.
As illustrated in
The electromagnetic coil 73 generates magnetic field that causes the fixed iron core 71 and the movable iron core 72 to be attracted and stuck to each other due to electromagnetic force. The electromagnetic coil 73 includes a winding 74 and a bobbin 75. The winding 74 passes through interspaces between a central leg portion and outer-side leg portions of each of the fixed iron core 71 and the movable iron core 72 and goes around the central leg portion. The bobbin 75 is a component around which the winding 74 is wound. The bobbin 75 includes a cylindrical portion on the inner diameter side of which the central leg portions of the respective ones of the fixed iron core 71 and the movable iron core 72 are inserted and on the outer diameter side of which the winding 74 is wound around. In addition, on the bobbin 75, flange portions that project from both ends of the cylindrical portion to the outer diameter side thereof in a flange shape are formed.
The return spring 76 is a biasing means for biasing the movable iron core 72 in a direction in which the movable iron core 72 moves away from the fixed iron core 71. The return spring 76 is, for example, a coil spring disposed across an interspace between the upper surface of the bobbin 75 of the electromagnetic coil 73 and the movable iron core 72
Each of the pairs of fixed contact pieces 61 and 62 and a corresponding movable contact piece 63 are an electrical contact configured to switch connection and disconnection of a circuit by coming into contact with and going away from each other.
As illustrated in
On the opposite side to the movable iron core 72 side of each of the movable contact pieces 63, a contact spring 77 is disposed.
Next, a configuration of the auxiliary contact unit 1 according to the first embodiment of the present invention will be described with reference to
As illustrated in
As illustrated in
In addition, as illustrated in
As illustrated in
In the first contact portion 2A, each of the pair of fixed contact pieces 3A and 4A extends in the X-direction and has a fixed contact formed on one end side and an external terminal portion formed on the other end side, as illustrated in
In the second contact portion 2B, each of the pair of fixed contact pieces 3B and 4B extends in the X-direction and has a fixed contact formed on one end side and an external terminal portion formed on the other end side, as illustrated in
Each of the pair of fixed contact pieces 3A and 4A, the movable contact piece 5A, the pair of fixed contact pieces 3B and 4B, and the movable contact piece 5B is formed of, for example, a flat plate-shaped conductive plate made of metal.
As illustrated in
As illustrated in
As illustrated in
The unit case 20 is formed by assembling the first case member 21 and the second case member 22, which are separate components, together. Specifically, with the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22 opposed to each other, the first case member 21 and the second case member 22 are fastened and fixed to each other, using, for example, a fastening member. With the first case member 21 and the second case member 22 fastened and fixed to each other, the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22 are air-tightly joined by means of, for example, welding. The first and second case members 21 and 22 are molded components that are separately formed by injecting, for example, epoxy-based thermosetting insulating resin into a mold.
The first case member 21 includes a flat plate portion and a rib portion formed on one surface side of the flat plate portion. On the other hand, the second case member 22 is formed of a flat plate. The joining portion 21a of the first case member 21 is formed by the rib portion, and the joining portion 22a of the second case member 22 is formed by a portion of the flat plate that faces the rib portion of the first case member 21.
As illustrated in
Each of the two guide rails 25 is composed of two divided pieces 25a and 25b into each of which a component is halved in a lateral direction orthogonal to the longitudinal direction, and one divided piece 25a is fixed to the first case member 21 and the other divided piece 25b is fixed to the second case member 22. The two pairs of divided pieces 25a and 25b constitute the guide rails 25 by joining the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22.
The auxiliary contact support 10 is housed in the housing portion 24 of the unit case 20 with the first and second sliding guide pieces 13 and 14 respectively supported by the cylindrical guide rails 25 in a freely slidable manner and the body portion 11 separated from the first case member 21 and the second case member 22.
Next, referring to
First, it is assumed that the electromagnetic coil 73 of the electromagnetic contactor 50 is in a de-energized state (non-excited state) and the electromagnetic contactor 50 is in a non-operating state (see
When the electromagnetic contactor 50 is in the released state, the first contact portion 2A of the auxiliary contact unit 1 is in a closed electrode state (b-contact state) in which the movable contact piece 5A is in contact with the respective ones of the pair of fixed contact pieces 3A and 4A and the second contact portion 2B of the auxiliary contact unit 1 is in an open electrode state (a-contact state) in which the movable contact piece 5B is separated from the respective ones of the pair of fixed contact pieces 3B and 4B, as illustrated in
When the electromagnetic contactor 50 that has been in the released state is brought to an operating state by energizing the electromagnetic coil 73 of the electromagnetic contactor 50, electromagnetic attractive force is generated on the leg portions and the pole contact surfaces of the fixed iron core 71. The movable iron core 72 being attracted to the fixed iron core 71 by the electromagnetic attractive force against the return spring 76 causes the movable contact support 64 to move forward toward the fixed iron core 71 and the movable contact pieces 63 held by the movable contact support 64 to move forward toward the pairs of fixed contact pieces 61 and 62.
When, as illustrated in
Subsequently, when the movable iron core 72 is attracted and stuck to the pole contact surfaces of the fixed iron core 71, the forward movement of the movable contact support 64 is stopped. In this state, the electromagnetic contactor 50 is brought to a completely closed state in which the movable contact pieces 63 are in contact with the pairs of fixed contact pieces 61 and 62 with a prescribed contact pressure by the contact springs 77. The completely closed state is maintained by attractive force between the movable iron core 72 and the fixed iron core 71.
While the electromagnetic contactor 50 transitions from the released state to the completely closed state, in the auxiliary contact unit 1, the auxiliary contact support 10 moves forward toward the lower side in conjunction with the forward movement of the movable contact support 64 of the electromagnetic contactor 50, which causes the movable contact piece 5A held by the auxiliary contact support 10 to move in a direction of moving away from the pair of fixed contact pieces 3A and 4A and, at the same time, the movable contact piece 5B held by the auxiliary contact support 10 to move in a direction of coming close to the pair of fixed contact pieces 3B and 4B. The movement of the auxiliary contact support 10 at this time is performed by the first sliding guide piece 13 and the second sliding guide piece 14 respectively sliding on the guide rails 25.
When the forward movement of the movable contact support 64 of the electromagnetic contactor 50 is stopped, the first contact portion 2A of the auxiliary contact unit 1 is brought to the open electrode state (a-contact state) in which the movable contact piece 5A is separated from the respective ones of the pair of fixed contact pieces 3A and 4A and the second contact portion 2B of the auxiliary contact unit 1 is brought to the closed electrode state (b-contact state) in which the movable contact piece 5B is in contact with the respective ones of the pair of fixed contact pieces 3B and 4B, as illustrated in
When the energization of the electromagnetic coil 73 of the electromagnetic contactor 50 is cut off while the electromagnetic contactor 50 is in the completely closed state, disappearance of attractive force from the fixed iron core 71 of the electromagnetic contactor 50 causes the movable contact support 64 to move backward in a direction of moving away from the fixed iron core 71 due to elastic force of the return spring 76. Thus, the movable contact pieces 63 move backward away from the pairs of fixed contact pieces 61 and 62, and the electromagnetic contactor 50 returns to the released state. At this time, in the auxiliary contact unit 1, the auxiliary contact support 10 moves backward toward the upper side in conjunction with the backward movement of the movable contact support 64 of the electromagnetic contactor 50, which causes the movable contact piece 5A held by the auxiliary contact support 10 to move in a direction of coming close to the pair of fixed contact pieces 3A and 4A and, at the same time, the movable contact piece 5B held by the auxiliary contact support 10 to move in a direction of moving away from the pair of fixed contact pieces 3B and 4B. The movement of the auxiliary contact support 10 at this time is performed by the first sliding guide piece 13 and the second sliding guide piece 14 respectively sliding on the guide rails 25.
When the backward movement of the movable contact support 64 of the electromagnetic contactor 50 is stopped, the first contact portion 2A of the auxiliary contact unit 1 returns to the closed electrode state (b-contact state) in which the movable contact piece 5A is in contact with the respective ones of the pair of fixed contact pieces 3A and 4A and the second contact portion 2B of the auxiliary contact unit 1 returns to the open electrode state (a-contact state) in which the movable contact piece 5B is separated from the respective ones of the pair of fixed contact pieces 3B and 4B (see
Next, main advantageous effects of the first embodiment will be described.
A unit case of a conventional auxiliary contact unit is produced by, with joining portions of the respective ones of first and second case members opposed to each other, pressure-connecting the first and second case members to each other by fastening force exerted by a fastening member, such as a bolt. The first and second case members are molded products that are individually formed by injecting insulating resin into a mold, and the joining portions of the respective ones of the first and second case members are not necessarily flat. Thus, there have sometimes been cases where, when the joining portions of the respective ones of the first and second case members were opposed to each other, a gap was formed. Such a gap serves as a passing route through which extraneous material, such as dirt and dust, invades a housing portion of the unit case from the outside, and, when insulating extraneous material that has invaded attaches to a contact portion of a fixed contact piece or a movable contact piece, the extraneous material becomes a factor inviting a contact failure.
In contrast, the auxiliary contact unit 1 of the first embodiment has the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22 air-tightly joined to each other by means of welding. Thus, since, even when a gap is formed when the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22 are opposed to each other, the gap is closed by the air-tight joining, it is possible to prevent extraneous material, such as dirt and dust, from invading the housing portion 24 of the unit case 20 from the outside through the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22. As a result, it is possible to suppress contact failure occurring between the pair of fixed contact pieces 3A and 4A and the movable contact piece 5A of the first contact portion 2A and contact failure occurring between the pair of fixed contact pieces 3B and 4B and the movable contact piece 5B of the second contact portion 2B, caused by insulating extraneous material that has invaded the housing portion 24 of the unit case 20 from the outside attaching to the fixed contacts of the fixed contact pieces 3A, 4A, 3B, and 4B and the movable contacts of the movable contact pieces 5A and 5B. Therefore, the first embodiment enables the auxiliary contact unit 1 that has higher reliability than a conventional auxiliary contact unit to be provided.
In addition, the conventional auxiliary contact unit is configured such that a body portion of an auxiliary contact support slides on guide portions that are respectively formed on the first and second case members in such a manner as to face each other. The guide portions of the respective ones of the first and second case members and the body portion of the auxiliary contact support are formed of an insulating resin. Thus, when the body portion of the auxiliary contact support is moved a large number of times, the guide portions of the case members and the body portion of the auxiliary contact support are worn and wear fragments from the wear attach to the fixed contacts of the fixed contact pieces and the movable contacts of the movable contact pieces as insulating extraneous material, which becomes a factor inviting contact failure between the fixed contact pieces and the movable contact pieces.
In contrast, in the auxiliary contact unit 1 of the first embodiment, the first and second sliding guide pieces 13 and 14 of the auxiliary contact support 10 and the two guide rails 25 are formed of a conductive material. Thus, wear fragments generated by wear of the first and second sliding guide pieces 13 and 14 of the auxiliary contact support 10 and wear of the two guide rails 25 when the first and second sliding guide pieces 13 and 14 of the auxiliary contact support 10 are moved a large number of times are conductive extraneous material, and, even when the conductive extraneous material attaches to the fixed contacts of the fixed contact pieces 3A, 4A, 3B, and 4B and the movable contacts of the movable contact pieces 5A and 5B, it is possible to reduce a factor inviting contact failure occurring between the pair of fixed contact pieces 3A and 4A and the movable contact piece 5A of the first contact portion 2A and contact failure occurring between the pair of fixed contact pieces 3B and 4B and the movable contact piece 5B of the second contact portion 2B. As a result, the auxiliary contact unit 1 of the first embodiment enables contact failure occurring between the pair of fixed contact pieces 3A and 4A and the movable contact piece 5A of the first contact portion 2A and contact failure occurring between the pair of fixed contact pieces 3B and 4B and the movable contact piece 5B of the second contact portion 2B caused by extraneous material that has been generated in the housing portion 24 of the unit case 20 to be suppressed.
In the above-described first embodiment, a configuration in which the joining portions 21a and 22a of the respective ones of the first case member 21 and the second case member 22 are air-tightly joined to each other by means of welding was described. However, the present invention is not limited to the air-tight joining by means of welding. For example, as illustrated in
An auxiliary contact unit 1A according to a second embodiment of the present invention basically has the similar configuration as the auxiliary contact unit 1 according to the above-described first embodiment except the following configuration.
That is, as illustrated in
The auxiliary contact unit 1A of the second embodiment includes the cover member 27, as described above. Therefore, the auxiliary contact unit 1A according to the second embodiment enables extraneous material that has invaded the housing portion 24 of the unit case 20 from the outside to be suppressed from attaching to fixed contacts of fixed contact pieces (3A, 4A, 3B, and 4B) and movable contacts of movable contact pieces 5A and 5B, using the cover member. The second embodiment enables the auxiliary contact unit 1A that has higher reliability than a conventional auxiliary contact unit to be provided.
Note that, although the second embodiment enables the auxiliary contact unit 1A having high reliability to be acquired without air-tightly joining the first case member 21 and the second case member 22 as in the above-described first embodiment, air-tightly joining the first case member 21 and the second case member 22 as in the above-described first embodiment enables the reliability to be further increased.
In addition, although joining portions of the respective ones of the cover member 27 and the first case member 21 do not have to be air-tightly joined, the joining portions may be air-tightly joined by means of welding as in the above-described first embodiment or may be air-tightly joined by means of an adhesive material as in the above-described variation.
Note that, in the above-described second embodiment, a configuration in which the cover member 27 is fixed to the first case member 21 was described. However, the present invention is not limited to the fixing of the cover member 27 to the first case member 21. For example, the cover member 27 may be fixed to the second case member 22 or may be fixed to both the first case member 21 and the second case member 22. In sum, the cover member 27 is only required to be fixed to at least either the first case member 21 or the second case member 22 in such a manner as to cover the auxiliary contact support 10.
In addition, in the first and second embodiments, a case where the first and second sliding guide pieces 13 and 14 and the two guide rails 25 are formed of a conductive material was described. However, the present invention is not limited to the case where both the sliding guide pieces (13 and 14) and the guide rails 25 are formed of a conductive material. For example, at least either the sliding guide pieces (13 and 14) or the guide rails 25 may be formed of a conductive material. In addition, at least either the first sliding guide piece 13 or the second sliding piece 14 may be formed of a conductive material, and at least either of the two guide rails 25 may be formed of a conductive material. In sum, it is only required that the amount of insulating extraneous material generated inside the housing portion 24 of the unit case 20 becomes smaller than a conventional configuration.
In addition, although, in the above-described first and second embodiments, a configuration in which a rib is formed on the first case member 21 was described, the present invention is not limited to the case where a rib is formed on the first case member 21. The present invention is applicable to a configuration in which a rib is formed on the second case member 22 and a configuration in which ribs are formed on both the first and second case members.
Recent years, cases of use of an electromagnetic contactor in a severe environment have increased, and it has become necessary that an auxiliary contact unit that is an attachment to an electromagnetic contactor has environmental resistance performance (dust resistance) that can withstand use in a severe environment. Therefore, the auxiliary contact unit of the present invention is useful for use in a severe environment.
Although the present invention was specifically described above, based on the above-described embodiments and variation, the present invention is not limited to the above-described embodiments and variation, and it is needless to say that the present invention can be embodied with various modifications without departing from the scope of the present invention.
1, 1A Auxiliary contact unit
2A First contact portion
2B Second contact portion
3A, 3B, 4A, 4B Fixed contact piece
5A, 5B Movable contact piece
10 Auxiliary contact support
11 Body portion
12 Coupling protrusion
13 First sliding guide piece
14 Second sliding guide piece
20 Unit case
21 First case member
21
a Joining portion
22 Second case member
22
a Joining portion
22
b Elongated opening
23 Welded portion
24 Housing portion
25 Guide rail
26 Adhesive material
27 Cover member
50 Electromagnetic contactor
51 Body case
60 Contact unit
61, 62 Fixed contact piece
63 Movable contact piece
64 Movable contact support
70 Electromagnet unit
71 Fixed iron core
72 Movable iron core
73 Electromagnetic coil
74 Winding
75 Bobbin
76 Return spring
77 Contact spring
| Number | Date | Country | Kind |
|---|---|---|---|
| 2019-208013 | Nov 2019 | JP | national |
This application is a continuation application filed under 35 U.S.C. § 111(a) of International Patent Application No. PCT/JP2020/007123, filed on Feb. 21, 2020, the contents of which are incorporated herein by reference.
| Number | Date | Country | |
|---|---|---|---|
| Parent | PCT/JP2020/007123 | Feb 2020 | US |
| Child | 17509649 | US |
