Electromagnetic relay

Patent metadata

Field	Value
Publication number	US-2018166244-A1
Application number	US-201615571043-A
Country	US
Kind code	A1
Filing date	Jun 22, 2016
Priority date	Jul 1, 2015
Publication date	Jun 14, 2018
Grant date	—

Abstract

An electromagnetic relay includes an electromagnet device, a contactor, and a trip device turning the contactor into an open state in which the contactor opens when an abnormal current flows. The electromagnet device includes a first excitation coil, a fixed element, first and second movable elements, and a permanent magnet. The contactor includes a fixed contact and a movable contact. In the electromagnetic relay, while the permanent magnet causes the first movable element to attractingly contact the second movable element, the fixed element attracts the first movable element due to a magnetic flux generated by the first excitation coil so as to move the second movable element together with the first movable element from a normal position to an attracted position. In the contactor, the movable contact moves, as the second movable element moves, so as to switch between a closed state in which the movable contact contacts the fixed contact and the open state in which the movable contact is removed from the fixed contact. The contactor is turned into the closed state when the second movable element is located at the attracted position. The trip device includes a second excitation coil connected in series to the contactor and a spring for acting a force on the second movable element in a direction away from the first movable element.

First claim

1 . An electromagnetic relay comprising:
an electromagnet device including a first excitation coil, a fixed element, a first movable element, a second movable element, and a permanent magnet, wherein, while the permanent magnet causes the first movable element to attractingly contact the second movable element, the fixed element attracts the first movable element due to a magnetic flux generated by the first excitation coil so as to move the second movable element together with the first movable element from a normal position to an attracted position; a contactor including a fixed contact and a movable contact, the movable contact being configured to move, as the second movable element moves, so as to switch between a closed state in which the movable contact contacts the fixed contact and an open state in which the movable contact is removed from the fixed contact, the contactor being turned into the closed state when the second movable element is located at the attracted position; and a trip device including a second excitation coil connected in series to the contactor and a spring for acting a force on the second movable element in a direction away from the first movable element, wherein, when the second movable element is located at the attracted position and an abnormal current equal to or larger than a predetermined value flows into the second excitation coil, the trip device releases the attracting contact of the second movable element by the permanent magnet by using a magnetic flux generated by the second excitation coil, and moves the second movable element by using the spring to turn the contactor into the open state.

2 . The electromagnetic relay according to claim 1 , wherein the permanent magnet is provided at the first movable element.

3 . The electromagnetic relay according to claim 1 , wherein the permanent magnet is provided at the second movable element.

4 . The electromagnetic relay according to claim 1 , wherein the electromagnet device further includes a magnetic-path portion that forms a closed magnetic path together with the first movable element and the second movable element, a magnetic flux generated in the permanent magnet passing through the closed magnetic path while the permanent magnet causes the first movable element to attractingly contact the second movable element.

5 . The electromagnetic relay according to claim 4 , wherein the magnetic-path portion is provided at the first movable element.

6 . The electromagnetic relay according to claim 4 , wherein the magnetic-path portion is provided at the second movable element.

7 . The electromagnetic relay according to claim 4 , further including a short-circuit prevention portion made of a nonmagnetic material and provided between the permanent magnet and the magnetic-path portion.

8 . The electromagnetic relay according to claim 1 , wherein
the second movable element is disposed opposite to the first movable element with respect to the fixed element in one direction in which the fixed element and the first movable element are arranged, the first movable element and the second movable element move in the one direction due to the magnetic flux generated by the first excitation coil, the trip device further includes a yoke that forms a part of a magnetic path through which the magnetic flux generated by the second excitation coil passes along a plane perpendicular to the one direction, the second movable element has a surface facing the first movable element when the second movable element is located at the attracted position, and the yoke projects from the surface of the second movable element opposite to the fixed element in the one direction.

9 . The electromagnetic relay according to claim 1 , wherein
the trip device further includes a yoke block that forms a part of a magnetic path through which the magnetic flux generated by the second excitation coil passes, and the second excitation coil is wound around a part of the yoke block.

10 . The electromagnetic relay according to claim 1 , wherein
the second movable element is disposed opposite to the first movable element with respect to the fixed element in one direction in which the fixed element and the first movable element are arranged, the electromagnetic relay further comprises a holding magnet provided opposite to the second movable element with respect to the first movable element in the one direction, and the holding magnet attracts the second movable element so as to hold the second movable element when a spring force caused by the spring moves the second movable element in a direction away from the first movable element.

11 . The electromagnetic relay according to claim 10 , further comprising
a magnetic body arranged with the holding magnet in the one direction, the magnetic body being magnetized by the holding magnet, wherein the electromagnet device further includes a tubular body accommodating the first movable element and the second movable element therein, the tubular body includes a tubular part having a tubular shape having two openings and a bottom plate closing one of the two openings of the tubular part, the first movable element and the second movable element are disposed inside the tubular part and arranged in the one direction such that the second movable element is located closer to the bottom plate than the first movable element is, and the magnetic body is disposed inside the tubular part and between the second movable element and the bottom plate.

12 . The electromagnetic relay according to claim 10 , further comprising
a magnetic body arranged with the holding magnet in the one direction, the magnetic body being magnetized by the holding magnet, wherein the electromagnet device further includes a tubular body accommodating the first movable element and the second movable element therein, the tubular body includes a tubular part having a tubular shape having two openings and a bottom plate closing one of the two openings of the tubular part, the first movable element and the second movable element are disposed inside the tubular part and arranged in the one direction such that the second movable element is located closer to the bottom plate than the first movable element is, and at least one portion of the bottom plate constitutes the magnetic body.

13 . The electromagnetic relay according to claim 10 , wherein
the electromagnet device further includes a tubular body accommodating the first movable element and the second movable element therein, the tubular body includes a tubular part having a tubular shape having two openings and a bottom plate closing one of the two openings of the tubular part, the first movable element and the second movable element are disposed inside the tubular part and arranged in the one direction such that the second movable element is located closer to the bottom plate than the first movable element is, and the holding magnet is disposed inside the tubular part and between the second movable element and the bottom plate.

14 . The electromagnetic relay according to claim 1 , wherein the trip device maintains the attracting contact of the second movable element by the permanent magnet when the second movable element is located at the attracted position and a normal current smaller than the predetermined value flows into the second excitation coil.

Assignees

• Panasonic Ip Man Co Ltd

Inventors

• Kobayashi Masakazu
• Kimoto Shinya
• Kanematsu Kenji

Classifications

• H01H50/18

  Movable parts of magnetic circuits, e.g. armature · CPC title

• H01H50/42

  Auxiliary magnetic circuits, e.g. for maintaining armature in, or returning armature to, position of rest, for damping or accelerating movement · CPC title

• H01H50/36 Primary

  Stationary parts of magnetic circuit, e.g. yoke · CPC title

• H01H71/32

  having permanently magnetised part · CPC title

• H01H50/44

  Magnetic coils or windings · CPC title