Electromagnetic relay

Abstract

An electromagnetic relay (1) comprises: a printed circuit board (3); and a first movable contact piece (6A). The printed circuit board (3) includes a first transmission line (24A), a second transmission line (25A), and a ground plate (23). The first movable contact piece (6A) is connected to the first transmission line (24A). The first movable contact piece (6A) extends from the first transmission line (24A) toward the second transmission line (25A). The first movable contact piece (6A) moves between a connection position and a separation position. At least a part of the ground plate (23) is disposed along the first movable contact piece (6A) in a direction from the first transmission line (24A) toward the second transmission line (25A). The ground plate (23) is formed such that the distance between the ground plate (23) and the first movable contact piece (6A) is substantially constant in a state where the first movable contact piece (6A) is placed at the connection position.

Description

electromagnetic relay

[0001] The present invention relates to an electromagnetic relay.

[0002] Some electromagnetic relays are used to open and close the transmission of high-frequency signals. For example, the electromagnetic relay disclosed in Patent Document 1 includes a movable contact piece, multiple fixed terminals, and a shield plate. When an electromagnet block is turned on and the movable contact piece is pressed by the electromagnet block, both ends of the movable contact piece come into contact with the multiple fixed terminals. This allows the transmission of high-frequency signals. On the other hand, when the electromagnet block is turned off and the movable contact piece is biased by a return spring, both ends of the movable contact piece separate from the multiple fixed terminals and come into contact with the shield plate. This blocks the transmission of high-frequency signals.

[0003] JP 2003-51234 A

[0004] In conventional electromagnetic relays, high-frequency signal transmission is switched by bringing both ends of the movable contact piece into contact with or separating them from the fixed terminal. In this case, the entire movable contact piece must be moved toward or away from the fixed terminal. This configuration creates a problem: the electromagnetic relay becomes complicated. Another problem is that the pressing force of the electromagnet block, i.e., the power of the electromagnet, is required to move the entire movable contact piece.

[0005] To solve this problem, attempts have been made to develop electromagnetic relays in which the movable contact piece is not entirely movable but is only partially movable. This type of electromagnetic relay can be configured as follows: One end of the movable contact piece is connected to a fixed terminal of a first transmission line. In this state, the movable contact piece is pressed by a pressing member, and the other end of the movable contact piece contacts a fixed terminal of a second transmission line. This allows transmission of high-frequency signals.

[0006] In this state, when the pressing member is released from the movable contact piece, the other end of the movable contact piece separates from the fixed terminal of the second transmission line and comes into contact with the shield plate, thereby blocking the transmission of high-frequency signals.

[0007] In this type of electromagnetic relay, one end of the movable contact piece is connected to a fixed terminal of a first transmission line, and the other end of the movable contact piece is connected to or disconnected from a fixed terminal of a second transmission line. When the other end of the movable contact piece is connected to the fixed terminal of the second transmission line, the other end of the movable contact piece is positioned above the one end of the movable contact piece.

[0008] As a result, the distance from the ground plate of the circuit board to the movable contact piece changes between one end of the movable contact piece and the other end of the movable contact piece. For example, this distance increases from the first transmission line to the second transmission line. As a result, the impedance of the movable contact piece changes between one end of the movable contact piece and the other end of the movable contact piece, which may result in a decrease in insulation loss characteristics. An object of the present invention is to provide an electromagnetic relay that can improve insulation loss characteristics.

[0009] An electromagnetic relay according to one aspect of the present invention includes a base block and a movable contact piece. The base block includes a first transmission line, a second transmission line, and a ground plate. The movable contact piece is connected to the first transmission line. The movable contact piece extends from the first transmission line toward the second transmission line. The movable contact piece moves between a connected position where it is connected to the second transmission line and a disconnected position where it is spaced upward from the second transmission line. At least a portion of the ground plate is disposed along the movable contact piece in a direction from the first transmission line toward the second transmission line. At least one of the ground plate and the movable contact piece is formed so that the distance between the ground plate and the movable contact piece is substantially constant when the movable contact piece is in the connected position.

[0010] In the electromagnetic relay according to this aspect, at least one of the ground plate and the movable contact piece is configured so that the distance between the ground plate and the movable contact piece is substantially constant when the movable contact piece is in the connected position. This configuration stabilizes the change in impedance of the movable contact piece when the movable contact piece is in the connected position, thereby improving insulation loss characteristics.

[0011] The ground plate may have an inclined portion that approaches the movable contact piece as it moves in the direction as viewed from above the base block. This configuration effectively stabilizes the change in impedance of the movable contact piece with a simple configuration, thereby effectively improving insulation loss characteristics.

[0012] The movable contact piece may have an inclined portion that approaches the ground plate as it moves in the direction described above when viewed from above the base block. This configuration effectively stabilizes the change in impedance of the movable contact piece with a simple structure, thereby effectively improving insulation loss characteristics.

[0013] The inclined portion may include a pair of inclined portions. In this case, the pair of inclined portions is arranged along both side surfaces of the movable contact piece when viewed from above the base block. This configuration reliably stabilizes the change in impedance of the movable contact piece. In other words, it reliably improves the insulation loss characteristics.

[0014] The ground plate may have a standing portion extending upward from the surface of the base block. In this case, the standing portion is arranged parallel to the movable contact piece when viewed from above the base block. This configuration reliably stabilizes the change in impedance of the movable contact piece. In other words, it reliably improves insulation loss characteristics.

[0015] In the electromagnetic relay of the present invention, the insulation loss characteristics can be improved.

[0016] 7 is a perspective view of an electromagnetic relay. FIG. 8 is a perspective view of an electromagnetic relay. FIG. 9 is an exploded perspective view of an electromagnetic relay. FIG. 10 is a perspective view of a printed circuit board. FIG. 11 is a top view of a printed circuit board, a first movable contact piece, a second movable contact piece, and a shield plate. FIG. 12 is a partially enlarged cross-sectional view (closed state) taken along line VII of FIG. 6. FIG. 13 is a partially enlarged cross-sectional view (open state) taken along line VII of FIG. 6. FIG. 14 is a perspective view of a base assembly and a stand as seen from below. FIG. 15 is a perspective view of a base assembly as seen from below. FIG. 16 is an exploded perspective view of a base assembly. FIG. 17 is a cross-sectional view of an electromagnetic relay in an open state. FIG. 18 is a cross-sectional view of an electromagnetic relay in a closed state. FIG. 19 is a perspective view of a movable block. FIG. 19 is a top view of a printed circuit board, a first movable contact piece, and a second movable contact piece in another embodiment. FIG. 19 is a top view of a printed circuit board, a first movable contact piece, and a second movable contact piece in another embodiment. FIG. 19 is a partially enlarged cross-sectional view (closed state) taken along line VII of FIG. 6 in another embodiment.

[0017] An electromagnetic relay according to an embodiment will be described below with reference to the drawings. The electromagnetic relay according to the present embodiment is used to switch between a high-frequency RF signal (an example of a high-frequency signal) and a low-frequency DC signal (an example of a low-frequency signal).

[0018] 1 and 2 are perspective views of an electromagnetic relay 1 according to an embodiment. As shown in FIGS. 1 and 2, the electromagnetic relay 1 includes a case 2, a base block 3, a base assembly 4, and a stand 5. The base block 3 includes a printed circuit board, a ceramic substrate, a resin molded product, a metal molded product, a flexible substrate, and a molded interconnect device (MID). In this embodiment, an example is shown in which the base block 3 is a printed circuit board. In the following description, the base block will be referred to as the "printed circuit board 3." Note that the case 2 is omitted in FIG. 2. In the following description, the direction in which the base assembly 4 and the stand 5 are arranged relative to the printed circuit board 3 is defined as "upward," and the opposite direction is defined as "downward."

[0019] As shown in Fig. 1, the case 2 is attached to the printed circuit board 3. The case 2 covers the upper surface of the printed circuit board 3, the base assembly 4, and the stand 5. Fig. 3 is an exploded perspective view of the electromagnetic relay 1. As shown in Fig. 3, the electromagnetic relay 1 includes a first movable contact piece 6A (an example of a movable contact piece), a second movable contact piece 6B (an example of a movable contact piece), and a shield plate 7. The first movable contact piece 6A, the second movable contact piece 6B, and the shield plate 7 are arranged on the printed circuit board 3.

[0020] FIG. 4 is a perspective view of the printed circuit board 3. Note that the shield plate 7 is omitted from FIG. 4. As shown in FIG. 4, the printed circuit board 3 includes first to fourth conductor layers 11-14 and first to third dielectric layers 15-17. The first to fourth conductor layers 11-14 are made of an electrically conductive material such as copper. The first to third dielectric layers 15-17 are made of a dielectric material. The first to fourth conductor layers 11-14 and the first to third dielectric layers 15-17 are alternately stacked one on top of the other.

[0021] The first conductor layer 11 is provided on the upper surface of the printed circuit board 3. Fig. 5 is a top view of the printed circuit board 3. Note that the shield plate 7 and the first and second movable contact pieces 6A, 6B are omitted in Fig. 5. As shown in Figs. 4 and 5, the first conductor layer 11 is provided with a first RF line 21A, a second RF line 21B, a first DC line 22A, a second DC line 22B, a first ground plate 23 (an example of a ground plate), and a pair of second ground plates 123A1, 123A2.

[0022] The first RF line 21A and the second RF line 21B are transmission lines for transmitting RF signals. The first RF line 21A includes a first transmission line 24A (an example of a first transmission line) and a second transmission line 25A (an example of a second transmission line). The first transmission line 24A and the second transmission line 25A are arranged apart from each other. The first transmission line 24A and the second transmission line 25A are electrically isolated from each other. The first transmission line 24A is connected to a first input terminal 26A. The second transmission line 25A is connected to a first RF terminal 27A. The first input terminal 26A and the first RF terminal 27A are each through-hole terminals provided on an end surface of the printed circuit board 3.

[0023] The second RF line 21B includes a third transmission line 24B (an example of a first transmission line) and a fourth transmission line 25B (an example of a second transmission line). The third transmission line 24B and the fourth transmission line 25B are arranged apart from each other. The third transmission line 24B and the fourth transmission line 25B are electrically isolated from each other. The third transmission line 24B is connected to a second input terminal 26B. The fourth transmission line 25B is connected to a second RF terminal 27B. The second input terminal 26B and the second RF terminal 27B are each a through-hole terminal provided on an end surface of the printed circuit board 3.

[0024] The first DC line 22A and the second DC line 22B are transmission lines for transmitting DC signals. The first DC line 22A is connected to the first transmission line 24A and the first ground plate 23. A first inductor 28A and a first capacitor 29A are disposed on the first DC line 22A. Note that in the drawings, only a portion of the first inductor 28A is denoted by the reference numeral 28A, and the reference numerals for the remaining first inductors 28A are omitted.

[0025] The first DC line 22A is connected to a first DC terminal 30A between the first inductor 28A and the first capacitor 29A. The first DC terminal 30A is a through-hole terminal provided on an end surface of the printed circuit board 3. The first DC line 22A, the first inductor 28A, and the first capacitor 29A function as a low-pass filter that passes DC signals but blocks RF signals. The first inductor 28A and the first capacitor 29A are configured to block high-frequency signals of, for example, 1 kHz or higher.

[0026] The second DC line 22B is connected to the third transmission line 24B and the first ground plate 23. A second inductor 28B and a second capacitor 29B are disposed on the second DC line 22B. Note that in the drawing, only a portion of the second inductor 28B is denoted by the reference numeral 28B, and the reference numerals for the remaining second inductors 28B are omitted.

[0027] The second DC line 22B is connected to a second DC terminal 30B between the second inductor 28B and the second capacitor 29B. The second DC terminal 30B is a through-hole terminal provided on an end surface of the printed circuit board 3. The second DC line 22B, the second inductor 28B, and the second capacitor 29B function as a low-pass filter that passes DC signals but blocks RF signals. The second inductor 28B and the second capacitor 29B are configured to block high-frequency signals of, for example, 1 kHz or higher.

[0028] 4 and 5 , the first ground plate 23 has a ground line 23A and a pair of ground portions 23B1 and 23B2. The ground line 23A extends between the first transmission line 24A and the third transmission line 24B and along the first transmission line 24A and the third transmission line 24B. The ground line 23A extends between the second transmission line 25A and the fourth transmission line 25B and along the second transmission line 25A and the fourth transmission line 25B.

[0029] The pair of ground portions 23B1 and 23B2 are formed integrally with the ground line 23A. The pair of ground portions 23B1 and 23B2 are arranged on both sides of the ground line 23A. The pair of ground portions 23B1 and 23B2 are arranged on both sides of the first movable contact piece 6A and the second movable contact piece 6B when viewed from above the printed circuit board 3.

[0030] The ground line 23A and the ground portion 23B1 are arranged along the first movable contact piece 6A in the longitudinal direction from the first transmission line 24A to the second transmission line 25A. The ground line 23A and the ground portion 23B1 are formed so that the distance between the ground line 23A and the ground portion 23B1 and the first movable contact piece 6A is substantially constant when the first movable contact piece 6A is in the connected position.

[0031] The ground line 23A and the ground portion 23B2 are arranged along the second movable contact piece 6B in the longitudinal direction from the third transmission line 24B to the fourth transmission line 25B. The ground line 23A and the ground portion 23B2 are formed so that the distance between the ground line 23A and the ground portion 23B2 and the second movable contact piece 6B is substantially constant when the second movable contact piece 6B is in the connected position.

[0032] 5 and 6, the ground line 23A has a first inclined portion 23A1 and a second inclined portion 23A2. The first inclined portion 23A1 and the second inclined portion 23A2 are provided between the pair of ground portions 23B1 and 23B2 in a direction perpendicular to the longitudinal direction. In FIG. 5, black circles are marked at the start and end points of the first inclined portion 23A1 and the second inclined portion 23A2.

[0033] The first inclined portion 23A1 is provided on the side surface of the ground line 23A on the ground portion 23B1 side. When viewed from above the printed circuit board 3, the first inclined portion 23A1 extends along the first movable contact piece 6A. When viewed from above the printed circuit board 3, the first inclined portion 23A1 inclines from the outside of the first movable contact piece 6A toward the side surface of the first movable contact piece 6A in the longitudinal direction from the first transmission line 24A toward the second transmission line 25A. When viewed from above the printed circuit board 3, the first inclined portion 23A1 extends along the first movable contact piece 6A so as to intersect with the side surface of the first movable contact piece 6A. A portion of the first inclined portion 23A1 is located below the first movable contact piece 6A.

[0034] When viewed from above the printed circuit board 3, the second inclined portion 23A2 extends along the second movable contact piece 6B. When viewed from above the printed circuit board 3, the second inclined portion 23A2 inclines from the outside of the first movable contact piece 6A to approach the side surface of the first movable contact piece 6A in the longitudinal direction from the first transmission line 24A to the second transmission line 25A. When viewed from above the printed circuit board 3, the second inclined portion 23A2 extends along the second movable contact piece 6B so as to intersect with the side surface of the second movable contact piece 6B. A portion of the second inclined portion 23A2 is located below the second movable contact piece 6B.

[0035] As shown in FIG. 7A , when the lower surfaces of the first and second movable contact pieces 6A and 6B are in contact with the second transmission line 25A and the fourth transmission line 25B, the inclination angles of the first and second inclined portions 23A1 and 23A2 are formed so that the impedance (√L / C) determined by the inductance component (L) and capacitance component (C) generated between them and the first ground plate 23 is constant.

[0036] The first and second inclined portions 23A1 and 23A2 are formed in the longitudinal range from the first and second connecting portions 32A and 32B of the first and second movable contact pieces 6A and 6B to the first and second contact portions 33A and 33B of the first and second movable contact pieces 6A and 6B. Specifically, the first and second inclined portions 23A1 and 23A2 are preferably formed in the longitudinal range from the first and second connecting portions 32A and 32B of the first and second movable contact pieces 6A and 6B to the base ends P1 and P2 of the first and second movable contact pieces 6A and 6B. As shown in FIGS. 5 and 6 , the ground portion 23B1 has a third inclined portion 23B11. The third inclined portion 23B11 is provided on a side surface of the ground portion 23B1 so as to face the first inclined portion 23A1. In FIG. 5 , black dots are indicated at the start and end points of the third inclined portion 23B11. When viewed from above the printed circuit board 3, the third inclined portion 23B11 extends along the first movable contact piece 6A. As shown in Fig. 5, when viewed from above the printed circuit board 3, the third inclined portion 23B11 is formed symmetrically to the first inclined portion 23A1 with respect to the central axis X1 in the longitudinal direction of the first movable contact piece 6A.

[0037] 5 and 6 , the third inclined portion 23B11 is inclined in the longitudinal direction from the third transmission line 24B to the fourth transmission line 25B, from the outside of the second movable contact piece 6B toward the side surface of the second movable contact piece 6B, when viewed from above the printed circuit board 3. When viewed from above the printed circuit board 3, the third inclined portion 23B11 extends along the first movable contact piece 6A so as to intersect with the side surface of the first movable contact piece 6A. A portion of the third inclined portion 23B11 is located below the first movable contact piece 6A. When viewed from above the printed circuit board 3, the first inclined portion 23A1 and the third inclined portion 23B11 are located along both side surfaces of the first movable contact piece 6A.

[0038] As shown in Figures 5 and 6, the ground portion 23B2 has a fourth inclined portion 23B21. The fourth inclined portion 23B21 is provided on a side surface of the ground portion 23B2 so as to face the second inclined portion 23A2. In Figure 5, black circles are marked at the start and end points of the fourth inclined portion 23B21. In a top view of the printed circuit board 3, the fourth inclined portion 23B21 extends along the second movable contact piece 6B. As shown in Figure 5, in a top view of the printed circuit board 3, the fourth inclined portion 23B21 is formed symmetrically to the second inclined portion 23A2 with respect to the longitudinal center axis X2 of the second movable contact piece 6B.

[0039] 5 and 6 , the fourth inclined portion 23B21 is inclined from the outside of the second movable contact piece 6B toward the side surface of the second movable contact piece 6B in the longitudinal direction from the third transmission line 24B to the fourth transmission line 25B when viewed from above the printed circuit board 3. When viewed from above the printed circuit board 3, the fourth inclined portion 23B21 extends along the second movable contact piece 6B so as to intersect with the side surface of the second movable contact piece 6B. A portion of the fourth inclined portion 23B21 is located below the second movable contact piece 6B. When viewed from above the printed circuit board 3, the second inclined portion 23A2 and the fourth inclined portion 23B21 are located along both side surfaces of the second movable contact piece 6B.

[0040] As shown in FIG. 7A , when the lower surfaces of the first and second movable contact pieces 6A and 6B are in contact with the second transmission line 25A and the fourth transmission line 25B, the inclination angles of the third and fourth inclined portions 23B11 and 23B21 are formed so that the impedance (√L / C) determined by the inductance component (L) and capacitance component (C) generated between them and the first ground plate 23 is constant.

[0041] The third and fourth inclined portions 23B11, 23B21 are formed in the longitudinal direction within a range from the first and second connecting portions 32A, 32B of the first and second movable contact pieces 6A, 6B to the first and second contact portions 33A, 33B of the first and second movable contact pieces 6A, 6B. In particular, the third and fourth inclined portions 23B11, 23B21 are preferably formed in the longitudinal direction within a range from the first and second connecting portions 32A, 32B of the first and second movable contact pieces 6A, 6B to the base ends P1, P2 of the first and second movable contact pieces 6A, 6B.

[0042] Each of the pair of second ground plates 123A1, 123A2 is formed separately from the first ground plate 23. The pair of second ground plates 123A1, 123A2 is disposed on both sides of the second transmission line 25A and the fourth transmission line 25B. In other words, the second transmission line 25A is disposed between the ground line 23A and the second ground plate 123A1. The fourth transmission line 25B is disposed between the ground line 23A and the second ground plate 123A2. The pair of second ground plates 123A1, 123A2 are disposed on both sides of the first movable contact piece 6A and the second movable contact piece 6B when viewed from above the printed circuit board 3.

[0043] The second to fourth conductor layers 12-14 shown in Fig. 4 are ground layers. As shown in Fig. 4 and Fig. 5, a plurality of through-hole terminals 31 are provided on the end surface of the printed circuit board 3. Note that in the drawings, only some of the through-hole terminals 31 are labeled with the reference numeral 31, and the reference numerals for the other through-hole terminals 31 are omitted. The through-hole terminals 31 connect the first ground plate 23 and the second to fourth conductor layers 12-14.

[0044] 4 and 6, the first movable contact piece 6A and the second movable contact piece 6B are arranged on the printed circuit board 3. The first movable contact piece 6A is arranged above the first RF line 21A. The first movable contact piece 6A extends from the first transmission line 24A toward the second transmission line 25A. The first movable contact piece 6A is formed in a rectangular shape that is long in one direction.

[0045] 4, the first movable contact piece 6A includes a first connecting portion 32A, a first contact portion 33A, and a first intermediate portion 34A. The first connecting portion 32A is connected to the first transmission line 24A. The first contact portion 33A is disposed above the second transmission line 25A. The first intermediate portion 34A is located between the first connecting portion 32A and the first contact portion 33A.

[0046] 7A and 7B, the first movable contact piece 6A is movable between a connected position and a disconnected position (an example of a disconnected position). As shown in Fig. 7A, when the first movable contact piece 6A is in the connected position, the first contact portion 33A comes into contact with the second transmission line 25A. As a result, the first movable contact piece 6A connects the first transmission line 24A and the second transmission line 25A.

[0047] 7B , when the first movable contact piece 6A is in the disconnecting position, the first contact portion 33A is separated from the second transmission line 25A. This causes the first movable contact piece 6A to disconnect the first transmission line 24A and the second transmission line 25A. In this state, the first movable contact piece 6A contacts the shield plate 7 in the disconnecting position. Preferably, the first movable contact piece 6A contacts the shield plate 7 via an insulating layer 107 in the disconnecting position. The insulating layer 107 is attached to the rear surface of the shield plate 7.

[0048] 7A , in a side view of the first movable contact piece 6A, when the first movable contact piece 6A is in the connected position, the first connecting portion 32A of the first movable contact piece 6A is connected to the first transmission line 24A, and the first contact portion 33A of the first movable contact piece 6A is in contact with the second transmission line 25A. In this state, the base end P1 of the first contact portion 33A is positioned above the first connecting portion 32A. The base end P1 of the first contact portion 33A may also be interpreted as the connection portion between the first contact portion 33A and the first intermediate portion 34A.

[0049] When the first movable contact piece 6A is in the connection position, the lower surface of the first movable contact piece 6A is inclined in the longitudinal direction from the first transmission line 24A to the second transmission line 25A. The distance between the first intermediate portion 34A and the first ground plate 23 gradually increases in the longitudinal direction from the first transmission line 24A to the second transmission line 25A.

[0050] 5 and 6, when viewed from above, the first intermediate portion 34A of the first movable contact piece 6A is located between the ground line 23A and the ground portion 23B1. More specifically, when viewed from above, a part of the first intermediate portion 34A of the first movable contact piece 6A is located between the first inclined portion 23A1 of the ground line 23A and the third inclined portion 23B11 of the ground portion 23B1.

[0051] 4 and 6, the second movable contact piece 6B is disposed above the second RF line 21B. The second movable contact piece 6B extends from the third transmission line 24B toward the fourth transmission line 25B. The second movable contact piece 6B is formed in a rectangular shape that is long in one direction.

[0052] 4, the second movable contact piece 6B includes a second connecting portion 32B, a second contact portion 33B, and a second intermediate portion 34B. The second connecting portion 32B is connected to the third transmission line 24B. The second contact portion 33B is disposed above the fourth transmission line 25B. The second intermediate portion 34B is located between the second connecting portion 32B and the second contact portion 33B.

[0053] 7A and 7B, like the first movable contact piece 6A, the second movable contact piece 6B is movable between a connected position and a disconnected position. As shown in Fig. 7A, when the second movable contact piece 6B is in the connected position, the second contact portion 33B comes into contact with the fourth transmission line 25B. As a result, the second movable contact piece 6B connects the third transmission line 24B and the fourth transmission line 25B.

[0054] 7B , when the second movable contact piece 6B is in the breaking position, the second contact portion 33B is separated from the fourth transmission line 25B. As a result, the second movable contact piece 6B breaks the connection between the third transmission line 24B and the fourth transmission line 25B. In this state, the second movable contact piece 6B is in contact with the shield plate 7 in the breaking position. It is preferable that the second movable contact piece 6B be in contact with the shield plate 7 via the insulating layer 107 in the breaking position.

[0055] 7A , in a side view of the second movable contact piece 6B, when the second movable contact piece 6B is in the connected position, the second connecting portion 32B of the second movable contact piece 6B is connected to the third transmission line 24B, and the second contact portion 33B of the second movable contact piece 6B is in contact with the fourth transmission line 25B. In this state, the base end P2 of the second contact portion 33B is positioned above the second connecting portion 32B. The base end P2 of the second contact portion 33B may also be interpreted as the connection portion between the second contact portion 33B and the second intermediate portion 34B.

[0056] When the second movable contact piece 6B is in the connection position, the lower surface of the second movable contact piece 6B is inclined in the longitudinal direction from the third transmission line 24B to the fourth transmission line 25B. The distance between the second intermediate portion 34B and the first ground plate 23 gradually increases in the longitudinal direction from the third transmission line 24B to the fourth transmission line 25B.

[0057] 5 and 6 , when viewed from above, the second intermediate portion 34B of the second movable contact piece 6B is located between the second inclined portion 23A2 and the ground portion 23B2 of the ground line 23A. More specifically, when viewed from above, a part of the second intermediate portion 34B of the second movable contact piece 6B is located between the second inclined portion 23A2 of the ground line 23A and the fourth inclined portion 23B21 of the ground portion 23B2.

[0058] By arranging the first and second movable contact pieces 6A, 6B relative to the first to fourth inclined portions 23A1, 23A2, 23B11, and 23B21 as described above, the distances between the ground line 23A and the ground portion 23B1 and the first and second movable contact pieces 6A, 6B are configured to be substantially constant. Note that the portions where the first to fourth inclined portions 23A1, 23A2, 23B11, and 23B21 are formed may be formed from a high-dielectric material.

[0059] As shown in Fig. 3, the shield plate 7 is disposed on the printed circuit board 3. As shown in Fig. 3 and Fig. 6, the shield plate 7 is connected to the first ground plate 23. More specifically, the shield plate 7 is connected to the first ground plate 23 and the pair of second ground plates 123A1 and 123A2. The shield plate 7 is made of a conductive material.

[0060] 6, 7A, and 7B, the shield plate 7 is disposed above the first contact portion 33A and the second contact portion 33B. That is, the first contact portion 33A is disposed between the shield plate 7 and the second transmission line 25A. The second contact portion 33B is disposed between the shield plate 7 and the fourth transmission line 25B. The shield plate 7 improves the isolation characteristics between the first RF line 21A and the second RF line 21B.

[0061] Fig. 8 is a perspective view of the base assembly 4 and the stand 5 as viewed from below. Fig. 9 is a perspective view of the base assembly 4 as viewed from below. Fig. 10 is an exploded perspective view of the base assembly 4. Figs. 11A and 11B are cross-sectional views of the electromagnetic relay 1. As shown in Figs. 8 to 10, the base assembly 4 includes a base 40, a coil block 41, and a movable block 42.

[0062] The coil block 41 includes a coil 43, a spool 44, and an iron core 45. The coil 43 is wound around the spool 44. The iron core 45 is disposed within the coil 43. The iron core 45 includes an intermediate portion 46, a first attraction portion 47, and a second attraction portion 48. The intermediate portion 46 is disposed within the coil 43 and extends in the axial direction of the coil 43. The first attraction portion 47 protrudes from the coil 43 in the axial direction of the coil 43. The first attraction portion 47 is disposed facing downward. The second attraction portion 48 protrudes from the coil 43 in the opposite direction to the first attraction portion 47 in the axial direction of the coil 43. The second attraction portion 48 is disposed facing downward.

[0063] The movable block 42 is operated by the electromagnetic force of the coil 43 to move the first movable contact piece 6A and the second movable contact piece 6B between the connection position and the disconnection position. Fig. 12 is a perspective view of the movable block 42. As shown in Fig. 12, the movable block 42 includes an iron piece 50, a first hinge spring 51, a second hinge spring 52, a permanent magnet 53, a card 54, and a movable insulating base 55.

[0064] The iron piece 50 is supported by a movable insulating base 55. The iron piece 50 includes a first end 56 and a second end 57. The first end 56 protrudes from the movable insulating base 55 in the axial direction of the coil 43. The first end 56 is disposed below the first attraction portion 47 of the iron core 45 and faces the first attraction portion 47. The second end 57 protrudes from the movable insulating base 55 in the opposite direction to the first end 56 in the axial direction of the coil 43. The second end 57 is disposed below the second attraction portion 48 of the iron core 45 and faces the second attraction portion 48.

[0065] The first hinge spring 51 is supported by the movable insulating base 55. The first hinge spring 51 protrudes from the movable insulating base 55 toward one side of the movable insulating base 55. The second hinge spring 52 is supported by the movable insulating base 55. The second hinge spring 52 protrudes from the movable insulating base 55 toward the other side of the movable insulating base 55. The permanent magnet 53 is attached to the upper surface of the movable insulating base 55.

[0066] The card 54 is supported by the movable insulating base 55. The card 54 protrudes downward from the movable insulating base 55. The card 54 is disposed above the first movable contact piece 6A and the second movable contact piece 6B. Specifically, the card 54 is disposed above the first intermediate portion 34A of the first movable contact piece 6A and the second intermediate portion 34B of the second movable contact piece 6B. The card 54 is connected to the underside of the first end portion 56 of the iron piece 50. The card 54 protrudes downward from the underside of the first end portion 56.

[0067] The movable insulating base 55 is supported to be swingable relative to the base 40. As shown in FIG. 10 , the base 40 includes support protrusions 58 and 59. As shown in FIG. 12 , the movable insulating base 55 includes support holes 60 and 61. The support protrusions 58 and 59 are disposed in the support holes 60 and 61 and support the movable insulating base 55 to be swingable. Also, as shown in FIG. 10 , the base 40 includes a first support recess 62 and a second support recess 63. The first hinge spring 51 is disposed in the first support recess 62. The first hinge spring 51 is connected to the base 40 at the first support recess 62. The second hinge spring 52 is disposed in the second support recess 63. The second hinge spring 52 is connected to the base 40 at the second support recess 63. The movable insulating base 55 is supported to be swingable by the base 40 around the first hinge spring 51 and the second hinge spring 52.

[0068] The stand 5 is disposed above the printed circuit board 3 and supports the base assembly 4. More specifically, the stand 5 supports the base 40. The coil block 41 is supported by the stand 5 via the base 40. The movable block 42 is supported by the stand 5 via the base 40. The stand 5 includes a frame 70 and a plurality of legs 71-74. As shown in FIG. 8 , the frame 70 has an opening 75 in its center. The movable block 42 is disposed within the opening 75 of the frame 70. The card 54 extends downward through the opening 75.

[0069] Next, the operation of the electromagnetic relay 1 will be described. FIG. 11A shows the electromagnetic relay 1 in an open state. When no current flows through the coil 43, the coil 43 is not excited, and the iron piece 50 is not attracted to the iron core 45. Due to the magnetic force of the permanent magnet 53, the first end 56 of the iron piece 50 is attracted to and contacts the first attraction portion 47 of the iron core 45. Therefore, the card 54 is separated from the first movable contact piece 6A and the second movable contact piece 6B, and the first movable contact piece 6A and the second movable contact piece 6B are each in the disconnected position. Therefore, in the first RF line 21A, the first transmission line 24A and the second transmission line 25A are disconnected from each other. Furthermore, in the second RF line 21B, the third transmission line 24B and the fourth transmission line 25B are disconnected from each other.

[0070] When current flows through the coil 43, the electromagnetic relay 1 is in the closed state shown in FIG. 11B . When the electromagnetic relay 1 is in the closed state, the electromagnetic force of the coil 43 causes the second end 57 of the iron piece 50 to be attracted to the second attraction portion 48 of the iron core 45 and rise. This causes the iron piece 50 to swing, and the first end 56 to descend. The card 54 descends together with the first end 56 and presses the first movable contact piece 6A and the second movable contact piece 6B, thereby moving the first movable contact piece 6A and the second movable contact piece 6B to their respective connected positions. This connects the first transmission line 24A and the second transmission line 25A to each other in the first RF line 21A. Furthermore, the third transmission line 24B and the fourth transmission line 25B to each other in the second RF line 21B.

[0071] When the current to the coil 43 is interrupted, the magnetic force of the permanent magnet 53 causes the iron piece 50 to rotate in the opposite direction, causing the second end 57 to descend and separate from the second attraction portion 48, while the first end 56 rises. The card 54 rises together with the first end 56 and separates from the first and second movable contact pieces 6A, 6B. As a result, the first and second movable contact pieces 6A, 6B return to their respective disconnected positions due to the elastic forces of the first and second movable contact pieces 6A, 6B. As a result, the first transmission line 24A and the second transmission line 25A are disconnected from each other in the first RF line 21A. Furthermore, the third and fourth transmission lines 24B, 25B are disconnected from each other in the second RF line 21B.

[0072] For example, when an RF signal is input to the first input terminal 26A and the second input terminal 26B of the electromagnetic relay 1, the electromagnetic relay 1 is closed. In this case, the first transmission line 24A and the second transmission line 25A are connected to each other, and the third transmission line 24B and the fourth transmission line 25B are connected to each other. Therefore, the RF signal passes from the first input terminal 26A through the first RF line 21A and is output from the first RF terminal 27A. The RF signal passes from the second input terminal 26B through the second RF line 21B and is output from the second RF terminal 27B. Meanwhile, the RF signal is cut by the first DC line 22A and the second DC line 22B, respectively, preventing the RF signal from being output from the first and second DC terminals 30A and 30B.

[0073] When a DC signal is input to the first input terminal 26A and the second input terminal 26B of the electromagnetic relay 1, the electromagnetic relay 1 is in an open state. In this state, the first transmission line 24A and the second transmission line 25A are disconnected from each other, and the third transmission line 24B and the fourth transmission line 25B are disconnected from each other. Therefore, the DC signal is output from the first input terminal 26A through the first DC line 22A and the first DC terminal 30A without passing through the first RF line 21A. The DC signal is output from the second input terminal 26B through the second DC line 22B and the second DC terminal 30B without passing through the second RF line 21B. This prevents the DC signal from flowing through the first movable contact 6A and the second movable contact 6B.

[0074] In the electromagnetic relay 1 according to the present embodiment described above, the first ground plate 23 is formed so that the distance between the first ground plate 23 and the first and second movable contact pieces 6A, 6B is substantially constant when the first and second movable contact pieces 6A, 6B are in the connected position. This configuration stabilizes the change in impedance of the first and second movable contact pieces 6A, 6B when the first and second movable contact pieces 6A, 6B are in the connected position, thereby improving the insulation loss characteristics.

[0075] The first ground plate 23 may have a first inclined portion 23A1 and a third inclined portion 23B11 that are inclined so as to approach the first movable contact piece 6A in the longitudinal direction when viewed from above the printed circuit board 3. The first ground plate 23 may have a second inclined portion 23A2 and a fourth inclined portion 23B21 that are inclined so as to approach the second movable contact piece 6B in the longitudinal direction when viewed from above the printed circuit board 3.

[0076] This simple configuration effectively stabilizes the change in impedance of the first and second movable contact pieces 6A, 6B, thereby effectively improving the insulation loss characteristics.

[0077] The first inclined portion 23A1 and the third inclined portion 23B11 are arranged along both side surfaces of the first movable contact piece 6A when viewed from above the printed circuit board 3. The second inclined portion 23A2 and the fourth inclined portion 23B21 are arranged along both side surfaces of the second movable contact piece 6B when viewed from above the printed circuit board 3.

[0078] This configuration can reliably stabilize the change in impedance of the first and second movable contact pieces 6A and 6B, thereby reliably improving the insulation loss characteristics.

[0079] While one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment and various modifications are possible without departing from the spirit and scope of the invention. As shown in Fig. 13, the first movable contact piece 6A may have inclined portions 61A1 and 61A2 that are inclined so as to approach the first ground plate 23 as they extend in the longitudinal direction when viewed from above the printed circuit board 3. The inclined portions 61A1 and 61A2 are provided on both side surfaces of the first intermediate portion 34A. In Fig. 13, black circles are marked at the start and end points of the inclined portions 61A1 and 61A2.

[0080] The second movable contact piece 6B may have inclined portions 61B1 and 61B2 that are inclined toward the first ground plate 23 as they extend in the longitudinal direction when viewed from above the printed circuit board 3. The inclined portions 61B1 and 61B2 are provided on both side surfaces of the second intermediate portion 34B. In Fig. 13, black circles are marked at the start and end points of the inclined portions 61B1 and 61B2.

[0081] In this case, the ground line 23A does not have the first inclined portion 23A1 and the second inclined portion 23A2, the ground portion 23B1 does not have the third inclined portion 23B11, and the ground portion 23B2 does not have the fourth inclined portion 23B21. That is, instead of the first inclined portion 23A1, the second inclined portion 23A2, the third inclined portion 23B11, and the fourth inclined portion 23B21, inclined portions 61A1 and 61A2 are formed on the first movable contact piece 6A, and inclined portions 61B1 and 61B2 are formed on the second movable contact piece 6B. The formation ranges of the inclined portions 61A1, 61A2, 61B1, and 61B2 can be changed depending on the inclination angle α.

[0082] This configuration can also achieve the same effects as those described above. Furthermore, the impedance changes of the first and second movable contact pieces 6A and 6B can be effectively stabilized with a simple configuration. This effectively improves the insulation loss characteristics.

[0083] 14, the first ground plate 23 may further have erected portions 23C1, 23C2, 23C3, and 23C4 extending upward from the surface of the printed circuit board 3. In this case, the erected portions 23C1, 23C2, 23C3, and 23C4 are arranged parallel to the first and second movable contact pieces 6A and 6B when viewed from above the printed circuit board 3.

[0084] Specifically, the standing portions 23C1 and 23C2 are arranged parallel to both side surfaces of the first intermediate portion 34A of the first movable contact piece 6A. The standing portions 23C1 and 23C2 are arranged above the first intermediate portion 34A of the first movable contact piece 6A. The standing portions 23C1 and 23C2 are arranged above the base end portion P1 of the first contact portion 33A of the first movable contact piece 6A. It is preferable that the standing portions 23C1 and 23C2 are arranged above the first contact portion 33A of the first movable contact piece 6A.

[0085] The erected portions 23C3, 23C4 are arranged parallel to both side surfaces of the second intermediate portion 34B of the second movable contact piece 6B. The erected portions 23C3, 23C4 are arranged above the second intermediate portion 34B of the second movable contact piece 6B. The erected portions 23C3, 23C4 are arranged above the base end portion P2 of the second contact portion 33B of the second movable contact piece 6B. It is preferable that the erected portions 23C3, 23C4 are arranged above the second contact portion 33B of the second movable contact piece 6B.

[0086] This configuration can reliably stabilize the change in impedance of the first and second movable contact pieces 6A and 6B, thereby reliably improving the insulation loss characteristics.

[0087] 15, a high-dielectric 23D1 made of a high-dielectric material or a metal body 23D2 may be disposed below the first and second movable contact pieces 6A and 6B, respectively. In this case, it is preferable that the upper surface of the high-dielectric 23D1 or the upper surface of the metal body 23D2 be formed so as to be parallel to the lower surface of the first intermediate portion 34A of the first movable contact piece 6A and the lower surface of the second intermediate portion 34B of the second movable contact piece 6B when the first and second movable contact pieces 6A and 6B are in the connected position. This configuration also improves insulation loss characteristics.

[0088] Although one embodiment of the present invention has been described above, the present invention is not limited to the above embodiment, and various modifications are possible without departing from the gist of the invention.

[0089] The configuration of the printed circuit board 3 is not limited to that of the above embodiment and may be modified. The configuration of the transmission lines of the printed circuit board 3 is not limited to that of the above embodiment and may be modified. For example, the second RF line 21B and the second DC line 22B may be omitted. The configuration of the terminals of the printed circuit board 3 is not limited to that of the above embodiment and may be modified. For example, the second input terminal 26B, the second RF terminal 27B, and the second DC terminal 30B may be omitted. The RF signal and the DC signal may flow in the opposite direction to that of the above embodiment. The configuration of the base assembly 4 is not limited to that of the above embodiment and may be modified. For example, the stand 5 is not limited to being separate from the base 40 and may be integrated with it.

[0090] In the electromagnetic relay of the present invention, the insulation loss characteristics can be improved.

[0091] 2: Case, 3: Printed circuit board, 6A: First movable contact piece, 6B: Second movable contact piece, 7: Shield plate, 23: First ground plate, 23A: Ground line, 23B1, 23B2: Ground portion, 24A: First transmission line, 25A: Second transmission line, 123A1, 123A2: Second ground plate, 23A1: First inclined portion, 23A2: Second inclined portion, 23B11: Third inclined portion, 23B21: Fourth inclined portion, 23C1, 23C2, 23C3, 23C4: Upright portion, 23D1: High dielectric, 23D2: Metal body

Claims

1. An electromagnetic relay comprising: a base block including a first transmission line, a second transmission line, and a ground plate; and a movable contact piece connected to the first transmission line and extending from the first transmission line toward the second transmission line, the movable contact piece moving between a connection position where it is connected to the second transmission line and a disconnected position above the second transmission line, wherein at least a portion of the ground plate is disposed along the movable contact piece in the direction from the first transmission line toward the second transmission line, and at least one of the ground plate and the movable contact piece is formed so that the distance between the ground plate and the movable contact piece is substantially constant when the movable contact piece is located at the connection position.

2. The electromagnetic relay according to claim 1, wherein the ground plate has an inclined portion that is inclined so as to approach the movable contact piece as it advances in the direction in which the base block is viewed from above.

3. The electromagnetic relay according to claim 1, wherein the movable contact piece has an inclined portion that is inclined so as to approach the ground plate as it moves in the direction as viewed from above the base block.

4. An electromagnetic relay as set forth in claim 2 or 3, wherein the inclined portion includes a pair of inclined portions, the pair of inclined portions being arranged along both side surfaces of the movable contact piece when viewed from above the base block.

5. An electromagnetic relay as described in claim 1, wherein the ground plate has an erected portion extending upward from a surface of the base block, the erected portion being arranged parallel to the movable contact piece when viewed from above the base block.

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