Electromagnetic relay

Abstract

An electromagnetic relay (1) comprises: a printed circuit board (3) that has first and third transmission lines (24A, 24B), second and fourth transmission lines (25A, 25B), and a first ground plate (23). The first ground plate (23) includes a ground line (23A). A shield plate (7) has a shield part (7A) and a first leg part (7B). The shield part (7A) is disposed over the second and fourth transmission lines (25A, 25B). The first leg part (7B) is disposed on the ground line (23A). First and second movable contact pieces (6A, 6B) are connected to the first transmission line (24A) and the third transmission line (24B), respectively. The first and second movable contact pieces (6A, 6B) move between a connection position and a cutoff position. The first and second movable contact pieces (6A, 6B) are in contact with the shield part (7A) at the cutoff 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 the movable contact piece is pressed by an 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 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, the transmission of high frequency signals is opened and closed by bringing both ends of a movable contact piece into contact with fixed terminals or by separating both ends of the movable contact piece from the fixed terminals.

[0005] In this case, it is necessary to move the entire movable contact piece toward or away from the fixed terminal. To achieve this configuration, 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.

[0006] 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.

[0007] In this state, when the pressing member is released from pressing 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 interrupting the transmission of high-frequency signals.

[0008] Meanwhile, attempts have also been made to develop electromagnetic relays with multiple high-frequency transmission lines, for example, two-pole high-frequency transmission lines. For example, when two-pole high-frequency transmission lines are used as differential transmission lines, a pair of movable contact pieces is provided for the two-pole high-frequency transmission lines. In this case, if the pair of movable contact pieces are brought into contact with two shield plates separately, there is a risk of variations in the isolation of high-frequency signals. An object of the present invention is to provide an electromagnetic relay that can stabilize the isolation characteristics of high-frequency signals.

[0009] An electromagnetic relay according to one aspect of the present invention includes a base block, a shield plate, and a pair of movable contact pieces. The base block has a pair of first transmission lines, a pair of second transmission lines, and a first ground plate. The first ground plate includes a ground line extending along and between the pair of second transmission lines. The shield plate has a shield portion and a first leg portion. The shield portion is disposed above the pair of second transmission lines and spaced apart from the pair of second transmission lines. The first leg portion is formed integrally with the shield portion. The first leg portion is disposed on the ground line.

[0010] The pair of movable contact pieces are connected to the pair of first transmission lines, respectively. The pair of movable contact pieces extend from the pair of first transmission lines toward the pair of second transmission lines, respectively. The pair of movable contact pieces move between a connected position where they are connected to the pair of second transmission lines and a disengaged position where they are spaced upward from the pair of second transmission lines. The pair of movable contact pieces contact the shield portion in the disengaged position.

[0011] In the electromagnetic relay according to this aspect, the ground line is disposed between the pair of second transmission lines and extends along the pair of second transmission lines, the first leg of the shield plate is disposed on the ground line, and the shield portion of the shield plate is disposed above the pair of second transmission lines and spaced apart from the pair of second transmission lines.

[0012] In this configuration, both of the pair of movable contact pieces contact the shield portion of one shield plate in the disengaged position, which reduces variations in the isolation characteristics of high-frequency signals. In other words, this electromagnetic relay can stabilize the isolation characteristics of high-frequency signals.

[0013] The first ground plate may further include a pair of ground portions, each of which is disposed on either side of the pair of movable contact pieces. The shield plate may further include a pair of second legs, each of which is integrally formed with the shield portion. The pair of second legs may be disposed on each of the pair of ground portions.

[0014] In this configuration, the shielding portion can be stably supported by the first leg and the pair of second legs. Furthermore, by stably supporting the shielding portion, it is possible to reduce variations in the isolation characteristics of high-frequency signals and stabilize the isolation characteristics of high-frequency signals.

[0015] The base block may further include a pair of second ground plates. In this case, the pair of second ground plates are disposed on both sides of the pair of second transmission lines. The shield plate may further include a pair of third leg portions. The pair of third leg portions are integrally formed with the shield portion. The pair of third leg portions are disposed on the pair of second ground plates, respectively.

[0016] In this configuration, the provision of a pair of second ground plates increases the flexibility of the support position of the shield portion. That is, the shield portion can be more stably supported by the first leg portion and the pair of third legs. Furthermore, by supporting the shield portion more stably, variation in the isolation characteristics of high-frequency signals can be reduced, thereby stabilizing the isolation characteristics of high-frequency signals.

[0017] The electromagnetic relay may further include an insulating layer provided between the pair of movable contact pieces and the shield plate, in which case the pair of movable contact pieces contact the insulating layer or the shield plate when the pair of movable contact pieces are in the disengaged position.

[0018] In this configuration, a pair of movable contact pieces contact the shield portion via the insulating layer when in the disengaged position, so that the insulating layer can prevent short circuits even in a configuration in which low-frequency signals are transmitted while high-frequency signal transmission is blocked.

[0019] In the electromagnetic relay of the present invention, it is possible to stabilize the isolation characteristics of high frequency signals.

[0020] 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. FIG. 12 is a top view of a printed circuit board, a first movable contact piece, a second movable contact piece, and a shield plate. FIG. 13 is a partially enlarged cross-sectional view taken along line VII of FIG. 6 (contacts are in a closed state). FIG. 14 is a partially enlarged cross-sectional view taken along line VII of FIG. 6 (contacts are in an open state). FIG. 15 is an external perspective view of the shield plate as seen from above. FIG. 16 is an external perspective view of the shield plate as seen from below. FIG. 17 is a perspective view of a base assembly and a stand as seen from below. FIG. 18 is a perspective view of the base assembly as seen from below. FIG. 19 is an exploded perspective view of the base assembly. FIG. 19 is a cross-sectional view of an electromagnetic relay in an open state. FIG. 19 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 partially enlarged cross-sectional view of a printed circuit board and a shield plate in another embodiment. FIG. 19 is a partially enlarged cross-sectional view of a printed circuit board and a shield plate in another embodiment.

[0021] 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).

[0022] 1 and 2 are perspective views of an electromagnetic relay 1 according to an embodiment. As shown in Fig. 1 and 2, the electromagnetic relay 1 includes a case 2, a base block 3, a base assembly 4, and a stand 5. Note that the case 2 is omitted from 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 the upper side, and the opposite direction is defined as the lower side.

[0023] As shown in FIG. 1 , the case 2 is attached to the base block 3. The case 2 covers the top surface of the base block 3, the base assembly 4, and the 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 in which the base block 3 is a printed circuit board is shown. In the following, the base block is described using the term "printed circuit board 3." 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.

[0024] 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.

[0025] 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.

[0026] 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.

[0027] 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.

[0028] 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.

[0029] 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.

[0030] 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.

[0031] 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.

[0032] 4, 5, and 6, 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.

[0033] 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.

[0034] 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 may be formed integrally with the first ground plate 23. The pair of second ground plates 123A1, 123A2 are arranged on both sides of the second transmission line 25A and the fourth transmission line 25B. In other words, the second transmission line 25A is arranged between the ground line 23A and the second ground plate 123A1. The fourth transmission line 25B is arranged between the ground line 23A and the second ground plate 123A2. The pair of second ground plates 123A1, 123A2 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.

[0035] 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.

[0036] As shown in FIG. 4 , 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 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 arranged 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.

[0037] As will be described later, the first movable contact piece 6A is movable between a connected position and a disconnected position (an example of a disconnected position). 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. This causes the first movable contact piece 6A to connect the first transmission line 24A and the second transmission line 25A.

[0038] 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. As a result, the first movable contact piece 6A disconnects the first transmission line 24A from the second transmission line 25A. In this state, the first movable contact piece 6A, in the disconnecting position, contacts the shield plate 7 via an insulating layer 107 (described later).

[0039] 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 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.

[0040] Like the first movable contact piece 6A, the second movable contact piece 6B is movable between a connect position and a disconnect position. When the second movable contact piece 6B is in the connect position, the second contact portion 33B contacts the fourth transmission line 25B. This causes the second movable contact piece 6B to connect the third transmission line 24B and the fourth transmission line 25B. When the second movable contact piece 6B is in the disconnect position, the second contact portion 33B disengages from the fourth transmission line 25B. This causes the second movable contact piece 6B to disconnect the third transmission line 24B and the fourth transmission line 25B. In this state, when in the disconnect position, the second movable contact piece 6B contacts the shield plate 7 via an insulating layer 107 (described later).

[0041] 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.

[0042] As shown in Fig. 6, the shield plate 7 extends from the first ground plate 23 above the second transmission line 25A and above the fourth transmission line 25B. As shown in Figs. 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.

[0043] 8A , the shield plate 7 includes a shield portion 7A, a first leg portion 7B, a pair of second leg portions 7C1 and 7C2, and a pair of third leg portions 7D1 and 7D2. The shield portion 7A includes a shield main body 7A1 and a pair of connecting portions 7A21 and 7A22. The shield main body 7A1 is formed in a rectangular plate shape.

[0044] As shown in FIGS. 6, 7A, and 7B, the shield body 7A1 is disposed above the second transmission line 25A and the fourth transmission line 25B at a distance from the second transmission line 25A and the fourth transmission line 25B.

[0045] As shown in Fig. 8A, the pair of connecting portions 7A21, 7A22 protrude separately from the shield body 7A1. The pair of connecting portions 7A21, 7A22 are spaced apart from each other. As shown in Fig. 6, the pair of connecting portions 7A21, 7A22 are located 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.

[0046] As shown in Fig. 8A, the first leg 7B is formed integrally with the shield body 7A1 of the shield part 7A. As shown in Fig. 6, the first leg 7B extends from the shield body 7A1 toward the ground line 23A. The first leg 7B is disposed on the ground line 23A.

[0047] As shown in Fig. 8A, the pair of second leg portions 7C1 and 7C2 are formed integrally with the pair of connecting portions 7A21 and 7A22 of the shield portion 7 A. As shown in Fig. 6, the pair of second leg portions 7C1 and 7C2 extend separately from the pair of connecting portions 7A21 and 7A22 toward the pair of ground portions 23B1 and 23B2.

[0048] As shown in Fig. 8A, the pair of third legs 7D1 and 7D2 are integrally formed with the shield body 7A1 of the shield part 7A. As shown in Fig. 6, the pair of third legs 7D1 and 7D2 extend from the shield body 7A1 toward the pair of second ground plates 123A1 and 123A2, respectively. The pair of third legs 7D1 and 7D2 are disposed on the pair of second ground plates 123A1 and 123A2, respectively.

[0049] As described above, in the shield plate 7, the first leg 7B is connected to the ground line 23A of the first ground plate 23. The pair of second leg portions 7C1 and 7C2 are respectively connected to the pair of ground portions 23B1 and 23B2 of the first ground plate 23. The pair of third leg portions 7D1 and 7D2 are respectively connected to the pair of second ground plates 123A1 and 123A2. In this state, the first movable contact piece 6A and the second movable contact piece 6B contact the shield body 7A1 via the insulating layer 107 shown in FIG. 8B .

[0050] As shown in Fig. 8B , the insulating layer 107 is provided on the shield plate 7. As shown in Fig. 7B , when the first movable contact piece 6A and the second movable contact piece 6B are in the interrupting position, the first contact portion 33A of the first movable contact piece 6A and the second contact portion 33B of the second movable contact piece 6B come into contact with the insulating layer 107. The insulating layer 107 may be provided on each of the first contact portion 33A of the first movable contact piece 6A and the second contact portion 33B of the second movable contact piece 6B. In this case, when the first movable contact piece 6A and the second movable contact piece 6B are in the interrupting position, the insulating layer 107 comes into contact with the shield plate 7.

[0051] The insulating layer 107 is a separate member from the first movable contact piece 6A, the second movable contact piece 6B, and the shield plate 7. The insulating layer 107 is attached to the shield plate 7 with an adhesive. The insulating layer 107 has a thickness of 3 μm or more and 80 μm or less. The insulating layer 107 is preferably formed of at least one of a high dielectric material and a high dielectric loss tangent material. For example, the insulating layer 107 is preferably formed of a high dielectric loss tangent material having a high dielectric constant. Specifically, the insulating layer 107 is preferably formed of a material such as ceramic, a resin material containing ceramic particles, ferrite, a resin material containing ferrite particles, or a radio wave absorber.

[0052] The insulating layer 107 may be formed on the shield plate 7 by coating the shield plate 7. For example, a fluorine coating and a polyamide-imide coating are applied to the portions of the shield plate 7 facing the first movable contact piece 6A and the second movable contact piece 6B. As a result, a resin layer that functions as the insulating layer 107 is formed on the shield plate 7. The resin layer is preferably formed to a thickness of 3 μm or more and 80 μm or less.

[0053] Fig. 9 is a perspective view of the base assembly 4 and the stand 5 as viewed from below. Fig. 10 is a perspective view of the base assembly 4 as viewed from below. Fig. 11 is an exploded perspective view of the base assembly 4. Figs. 12A and 12B are cross-sectional views of the electromagnetic relay 1. As shown in Figs. 9 to 12B, the base assembly 4 includes a base 40, a coil block 41, and a movable block 42.

[0054] 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.

[0055] 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. 13 is a perspective view of the movable block 42. As shown in Fig. 13, 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.

[0056] 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.

[0057] 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.

[0058] 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.

[0059] The movable insulating base 55 is supported to be swingable relative to the base 40. As shown in FIG. 11 , the base 40 includes support protrusions 58 and 59. As shown in FIG. 13 , 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. 11 , 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.

[0060] 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. 9 , 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.

[0061] Next, the operation of the electromagnetic relay 1 will be described. FIG. 12A 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 the first attraction portion 47 of the iron core 45 and is in contact with the first attraction portion 47. 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. In addition, in the second RF line 21B, the third transmission line 24B and the fourth transmission line 25B are disconnected from each other.

[0062] When current flows through the coil 43, the electromagnetic relay 1 is in the closed state shown in FIG. 12B . 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.

[0063] 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.

[0064] 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.

[0065] 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.

[0066] In the electromagnetic relay 1 according to the present embodiment described above, the ground line 23A is disposed between the second transmission line 25A and the fourth transmission line 25B and extends along the second transmission line 25A and the fourth transmission line 25B. In this state, the first leg portion 7B of the shield plate 7 is disposed on the ground line 23A. The shield portion 7A of the shield plate 7 is disposed above the second transmission line 25A and the fourth transmission line 25B and spaced apart from the second transmission line 25A and the fourth transmission line 25B.

[0067] In this configuration, both the first movable contact piece 6A and the second movable contact piece 6B contact the shield portion 7A of one shield plate 7 in the interrupting position, thereby suppressing variations in the isolation characteristics of high-frequency signals. In other words, the electromagnetic relay 1 can stabilize the isolation characteristics of high-frequency signals.

[0068] The pair of ground portions 23B1, 23B2 are arranged on both sides of the first movable contact piece 6A and the second movable contact piece 6B. The shield plate 7 further has a pair of second leg portions 7C1, 7C2. The pair of second leg portions 7C1, 7C2 are formed integrally with the shield portion 7A. The pair of second leg portions 7C1, 7C2 are respectively arranged on the pair of ground portions 23B1, 23B2.

[0069] In this configuration, the shield portion 7A can be stably supported by the first leg portion 7B and the pair of second legs 7C1, 7C2. Furthermore, by stably supporting the shield portion 7A, it is possible to reduce variations in the isolation characteristics of high-frequency signals and stabilize the isolation characteristics of high-frequency signals.

[0070] The pair of second ground plates 123A1 and 123A2 are arranged on both sides of the second transmission line 25A and the fourth transmission line 25B. The shield plate 7 further has a pair of third legs 7D1 and 7D2. The pair of third legs 7D1 and 7D2 are formed integrally with the shield portion 7A. The pair of third legs 7D1 and 7D2 are respectively arranged on the pair of second ground plates 123A1 and 123A2.

[0071] In this configuration, the provision of a pair of second ground plates 123A1, 123A2 increases the flexibility of the support position of the shield portion 7A. That is, the shield portion 7A can be more stably supported by the first leg portion 7B and the pair of third legs 7D1, 7D2. Furthermore, by supporting the shield portion 7A more stably, variations in the isolation characteristics of high-frequency signals can be reduced, thereby stabilizing the isolation characteristics of high-frequency signals.

[0072] In this embodiment, an example is shown in which the shield part 7A is supported by five legs (a first leg 7B, a pair of second legs 7C1, 7C2, and a pair of third legs 7D1, 7D2), but the number of legs may be less than five or more than five.

[0073] In the interruption position, the first movable contact piece 6A and the second movable contact piece 6B come into contact with the shield portion 7A via the insulating layer 107. With this configuration, even in a configuration in which low-frequency signals are transmitted while high-frequency signal transmission is interrupted, the insulating layer 107 can prevent short circuits.

[0074] 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.

[0075] 14, the insulating layer 207 may be disposed between the first ground plate 23 and the shield plate 7, and between the second ground plates 123A1, 123A2 and the shield plate 7. Note that FIG. 14 shows a cross section on the first movable contact piece 6A side, and the reference numerals for the cross section on the second movable contact piece 6B side are shown in parentheses. Even with this configuration, when the first movable contact piece 6A and the second movable contact piece 6B come into contact with the shield plate 7, the insulating layer 207 can prevent a short circuit of low-frequency signals.

[0076] As shown in Fig. 15, the electromagnetic relay 1 may have a first insulating layer 307, a second insulating layer 308, a third insulating layer 309, and a fourth insulating layer 310. Fig. 15 is a cross-sectional view of the printed circuit board 3 cut in a direction perpendicular to the longitudinal direction of the first movable contact piece 6A. The reference numerals for the cross section on the second movable contact piece 6B side are shown in parentheses. In Fig. 15, vias 401, 402, and 403, which will be described later, are shown in a simplified form.

[0077] In this case, the first dielectric layer 15 is used as the first insulating layer 307, the second dielectric layer 16 is used as the second insulating layer 308, and the third dielectric layer 17 is used as the third insulating layer 309.

[0078] Here, the second conductor layer 12 has a fifth conductor layer 12A connected to the shield plate 7 and a sixth conductor layer 12B connected to the fourth conductor layer 14. The fifth conductor layer 12A is connected to the first ground plate 23 and the pair of second ground plates 123A1 and 123A2 of the first conductor layer 11 through vias 401. The shield plate 7 is connected to the first ground plate 23 and the pair of second ground plates 123A1 and 123A2.

[0079] The sixth conductor layer 12B is a conductor layer separate from the fifth conductor layer 12A. The sixth conductor layer 12B is disposed around the fifth conductor layer 12A at a distance. The sixth conductor layer 12B is connected to the third conductor layer 13 via a via 402. The third conductor layer 13 is connected to the fourth conductor layer 14 via a via 403.

[0080] The fourth insulating layer 310 is disposed between the fifth conductor layer 12A and the sixth conductor layer 12B, between the first insulating layer 307 and the second insulating layer 308. For example, the fourth insulating layer 310 is disposed between the fifth conductor layer 12A and the sixth conductor layer 12B so as to surround the fifth conductor layer 12A. As a result, the fifth conductor layer 12A and the sixth conductor layer 12B are insulated from each other by the fourth insulating layer 310. In this case, at least one of the sixth conductor layer 12B, the third conductor layer 13, and the fourth conductor layer 14 is interpreted as an example of a ground plate.

[0081] Even with this configuration, when the first movable contact piece 6A and the second movable contact piece 6B come into contact with the shield plate 7, the first to fourth insulating layers 307, 308, 309, and 310 can prevent short-circuiting of low-frequency signals. Furthermore, with this configuration, the fifth conductor layer 12A can ensure a large conductor area, thereby improving the isolation characteristics of high-frequency signals.

[0082] In the above embodiment, an example in which there are two movable contact pieces (the first movable contact piece 6A and the second movable contact piece 6B) has been shown, but there may be three or more movable contact pieces. Also, in the above embodiment, an example in which there is one shield plate 7 has been shown, but there may be two or more shield plates 7. In the above embodiment, an example in which there is one insulating layer 107 has been shown, but there may be two or more insulating layers 107.

[0083] 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. 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.

[0084] In the electromagnetic relay of the present invention, it is possible to stabilize the isolation characteristics of high frequency signals.

[0085] 2: Case, 3: Printed circuit board, 6A: First movable contact piece, 6B: Second movable contact piece, 7: Shield plate, 7A: Shield portion, 7B: First leg portion, 7C1, 7C2: Second leg portion, 7D1, 7D2: Third leg portion, 11: First conductor layer, 12: Second conductor layer, 12A: Fifth conductor layer, 12B: Sixth conductor layer, 13: Third conductor layer, 14: Fourth conductor layer, 23: First ground plate, 23A: Ground line, 23B1, 23B2: Ground portion, 24A: First transmission line, 25A: Second transmission line, 107, 207, 307, 308, 309, 310: Insulating layer, 123A1, 123A2: Second ground plate

Claims

1. An electromagnetic relay comprising: a base block having a pair of first transmission lines, a pair of second transmission lines, and a first ground plate including a ground line extending along the pair of second transmission lines between the pair of second transmission lines; a shield plate having a shield section arranged above the pair of second transmission lines and spaced apart from the pair of second transmission lines, and a first leg section formed integrally with the shield section and arranged on the ground line; and a pair of movable contact pieces connected to the pair of first transmission lines, extending from the pair of first transmission lines toward the pair of second transmission lines, respectively, and movable between a connection position where the contact is connected to the pair of second transmission lines and a detached position spaced upward from the pair of second transmission lines, and contacting the shield section at the detached position.

2. An electromagnetic relay as described in claim 1, wherein the first ground plate further includes a pair of ground portions arranged on both sides of the pair of movable contact pieces, and the shield plate further has a pair of second leg portions formed integrally with the shield portion and respectively arranged on the pair of ground portions.

3. An electromagnetic relay as claimed in claim 1 or 2, wherein the base block further has a pair of second ground plates, the pair of second ground plates being arranged on both sides of the pair of second transmission lines, and the shield plate further has a pair of third leg portions formed integrally with the shield portion and respectively arranged on the pair of second ground plates.

4. An electromagnetic relay as described in claim 1 or 2, further comprising an insulating layer provided between said pair of movable contact pieces and said shield plate, wherein said pair of movable contact pieces contact said insulating layer or said shield plate when said pair of movable contact pieces are positioned in said disengaged position.

Images