Electromagnetic relay, joining structure for hinge spring and yoke in the electromagnetic relay

Abstract: An electromagnetic relay has an iron core (1), an armature (2), a coil (12) wound around the iron core (1), a yoke (3), a hinge spring (6), and a joining structure. The yoke (3) is fastened rigidly to the iron core (1) and has an engaging hole (3b) and a fitting portion (3a, 3d). The hinge spring (6) is used to support the armature (2) rotatably on the yoke (3), and the joining structure is used to join the hinge spring (6) to the yoke (3) in the electromagnetic relay. The hinge spring (6) has a tongue (6a) and a dish-shaped portion (6b), and the yoke (3) has an engaging hole (3b) and a fitting portion (3a, 3d) for engaging with the tongue (6a) and the dish-shaped portion (6b). The hinge spring (6) is joined to the yoke (3) by inserting and fitting the hinge spring (6) into the yoke (3). This structure serves to simplify the process of assembling the hinge spring to the yoke and drastically reduce the number of assembling steps required. Further, in a flux penetration preventing structure of the electromagnetic relay, a coil bobbin (4) is formed, integral with or separate from a base block (9), and a venting portion (4c), for allowing air trapped in a center hole in the coil bobbin (4) to be vented therethrough, is formed in an upper flange (4b) of the coil bobbin (4). Therefore, sealing work of the base block of the electromagnetic relay can be performed smoothly and pinhole-free sealing thereof can be provided.

Description: The present invention relates to an electromagnetic relay with a joining structure for a hinge spring and a yoke. Document DE 30 02 029 A1 discloses an electromagnetic relay according to the preamble of claim 1. In the construction of an electromagnetic relay, for example, a coil is wound around an iron core to construct an electromagnet, a yoke as a component to complete a magnetic circuit with it is fastened rigidly to the iron core and an armature is rotatably mounted in such a manner as to bridge between the yoke and the head of the iron core of the electromagnet to construct an electromagnet structure. Then, one end of this electromagnet structure is fixed to the yoke and the other end thereof is made to engage with the armature, the rotatable movement of the armature being supported by a plate-like hinge spring formed from a resilient member. Assembling the hinge spring to the yoke in the electromagnetic relay requires assembling equipment (such as a crimping tool or a welder). This has presented the problem in that the assembling requires many assembling steps and takes a lot of time. An object of the present invention is to provide a simple part-to-part joining structure that allows the hinge spring to be assembled to the yoke in an electromagnetic relay without requiring specific assembling equipment, and thereby simplify the assembly process and drastically reduce the number of assembling steps required. According to the present invention, there is provided an electromagnetic relay comprising an iron core; an armature; a coil wound around the iron core; a yoke, fastened rigidly to the iron core, having an engaging hole and a fitting portion; a hinge spring for supporting the armature rotatably on the yoke; and a joining structure for joining the hinge spring to the yoke in the electromagnetic relay, characterised in that the hinge spring includes a tongue and a dish-shaped portion; the yoke includes an engaging hole and a fitting portion for engaging with the tongue and the dish-shaped portion, and the hinge spring is joined to the yoke by inserting and fitting the hinge spring into the yoke. The dish-shaped portion of the hinge spring may include a center hole, and the fitting portion of the yoke may include a recessed part and a raised part corresponding to the center hole of the dish-shaped portion. The recessed part and the raised part of the fitting portion engaged with the hinge spring on the yoke may be formed within a plate thickness of the yoke. The dish-shaped portion may be formed as a circular shape. The tongue of the hinge spring may be formed as a U-shape. The present invention will be more clearly understood from the description of a preferred embodiment by way of example as set forth below with reference to the accompanying drawings, wherein: Figure 1A is an exploded perspective view for explaining one example of a joining structure of a yoke and a hinge spring in a prior art electromagnetic relay; Figure 1B is a perspective view of the yoke and hinge spring assembled together in accordance with Figure 1A; Figure 2 is a perspective view showing the entire construction of an electromagnetic relay according to the present invention; Figure 3 is an exploded perspective view showing the entire construction of the electromagnetic relay of the present invention; Figure 4A is an enlarged front view of one example of the hinge spring of the relay shown in Figures 2 and 3; Figure 4B is a side view of the hinge spring shown in Figure 4A; Figure 5A is an exploded perspective view showing one example of the joining structure of the yoke and hinge spring; and Figure 5B is a perspective view of the yoke and hinge spring assembled together in accordance with Figure 5A. Before describing the electromagnetic relay and the joining structure of the hinge spring and yoke in the electromagnetic relay according to the present invention, the problem involved in the assembly of the hinge spring and yoke in the prior art electromagnetic relay will be described with reference to Figures 1A and 1B. Figure 1A is an exploded perspective view for explaining one example of the joining structure of the yoke and hinge spring in the prior art electromagnetic relay, and Figure 1B is a perspective view of the yoke and hinge spring assembled together in accordance with Figure 1. Generally, in constructing the electromagnetic relay, a coil is wound around an iron core (1) to construct an electromagnet, and a yoke 3 as a component to complete a magnetic circuit with it is fastened rigidly to the iron core and an armature (2) is rotatably mounted in such a manner as to bridge between the yoke 3 and the head (la) of the iron core of the electromagnet to construct an electromagnet structure. Then, one end of this electromagnet structure is fixed to the yoke 3 and the other end thereof is made to engage with the armature, the rotatable movement of the armature being supported by a plate-like hinge spring 6 formed from a resilient member. In the prior art electromagnetic relay of this type, the structure shown in Figures 1A and 1B, for example, has been employed to secure the hinge spring 6 to the yoke 3; that is, protrusions 3d are provided on one surface of the yoke 3, and the protrusions 3d on the yoke 3 are inserted into the holes 6e opened through the hinge spring 6, after which the protrusions 3d on the yoke 3 are deformed by crimping (crimping at crimping portions 3e), or the hinge spring 6 is welded directly to the surface of the yoke 3 (welding at welding portions 3f), thus joining the hinge spring 6 and yoke 3 in an integral fashion. However, the yoke/hinge spring joining method of the prior art shown in Figures 1A and 1B has had the problem that fixing the hinge spring 6 to the yoke 3 necessarily entails the use of specific assembling equipment (such as a crimping tool or a welder) and the number of assembling steps increases. In view of the above-described problem with the prior art electromagnetic relay (the yoke/hinge spring assembly structure), according to a first mode of the present invention, a U-shaped tongue is formed on the hinge spring by stamping, and this tongue is passed through an engaging hole opened through the yoke and is made to engage with it; further, a fitting recess having a protrusion thereon is formed in the yoke, and a hole opened through the hinge spring is fitted onto the protrusion, thereby fixing the hinge spring to the yoke. Figure 2 is a perspective view showing the entire construction of the electromagnetic relay according to the present invention, and Figure 3 is an exploded perspective view showing the entire construction of the electromagnetic relay of the present invention. In Figures 2 and 3, reference numeral 1 is an iron core, 2 is an armature, 3 is a yoke, 4 is a coil bobbin, 5 is a coil terminal, 6 is a hinge spring, 9 is a base block, 10 is a card, and 12 is a coil. Further, reference numeral 7 is a movable contact spring, 7a is a movable contact, 8 is a stationary contact spring, 8a is a stationary contact, and 11 is a case. As shown in Figure 3, in the assembly process of the electromagnetic relay, the coil bobbin 4 is placed on the base block 9 made of an insulating material, and the coil 12 is wound around the coil bobbin 4. Further, the iron core 1 is inserted through a center hole 4a in the coil bobbin 4 until the lower end portion 1b of the iron core 1 reaches the bottom of the base block 9. After that, the L-shaped yoke 3 is inserted through a hole 9a in the base block 9 from the underside thereof, and a hole 3c opened through the yoke 2 is fitted onto the lower end portion 1b of the iron core 1 to fix the yoke 3 to the base block 9, so that an electromagnet is constructed. Here, the coil bobbin 4 may be formed integrally with the base block 9 beforehand or may be fabricated as a separate coil component. Thereafter, the hinge spring 6 is assembled to the yoke 6; alternatively, the yoke 6 may be fitted with the hinge spring 6 beforehand. Next, the movable contact spring 7 and the stationary contact spring 8 are inserted in the base block 9 and secured in place, after which the armature 2 is engaged with the free end 6d of the hinge spring 6 so that the armature 2 is held opposite the head 1a of the iron core. Further, the card 10 is fitted in position by engaging it onto the armature 2 and the movable contact spring 7. Here, the coil terminals 5 may be attached beforehand by inserting them in the base block 9 during the process of molding the latter. Finally, the case 11 is mounted to complete the assembly of the electromagnetic relay. Figure 4A is an enlarged front view of one example of the hinge spring for explaining the first mode of the present invention, and Figure 4B is a side view of the hinge spring shown in Figure 4A. In Figures 4A and 4B, reference numeral 3a is the fitting recess formed in the yoke, 3b is the engaging hole formed in the yoke, 3d is the protrusion formed on the yoke, 6a is the tongue provided on the hinge spring, 6b is the dish-shaped portion formed on the hinge spring, and 6c is a hole (center hole) of the dish-shaped portion 6b opened through the hinge spring 6. The structure (joining structure) of the yoke 3 and hinge spring 6, the essential components of the first mode of the present invention, will be described with reference to Figures 4A and 4B. As shown in Figures 4A and 4B, the hinge spring 6 is formed from a plate-like resilient member, and the dish-shaped portion 6b, formed by extrusion with a press into such a shape as to bulge around the outer periphery thereof, is provided in the lower end portion of the hinge spring 6. Further, the hole 6c is opened through the center of the dish-shaped portion 6b. On the hinge spring 6 is also formed the U-shaped tongue 6a by cutting and bending a portion upward of the portion where the dish-shaped portion 6b is formed. The free end 6d of the hinge spring 6 is bent in a dogleg shape in such a manner as to protrude in the same direction as the bulging direction of the dish-shaped portion 6b and to engage with the armature 2. Figure 5A is an exploded perspective view showing one example of the joining structure of the yoke and hinge spring according to one embodiment of the first mode of the present invention, and Figure 5B is a perspective view of the yoke and hinge spring assembled together in accordance with Figure 5A. As shown in Figures 5A and 5B, the yoke 3 to which the hinge spring 6 is joined is provided with the fitting recess 3a into which the dish-shaped portion 6b of the hinge spring 6 is fitted and with the engaging hole 3b in which the U-shaped tongue 6a of the hinge spring 6 engages. That is, the U-shaped tongue 6a provided on the hinge spring 6 is made to engage with the engaging hole 3a formed in the yoke, and the dish-shaped portion 6b provided on the hinge spring 6 is made to fit into the fitting recess 3a formed in the yoke 3. Here, the protrusion 3d provided on the yoke 3 is made to pass through the hole 6c opened in the center of the dish-shaped portion 6d of the hinge spring 6. In this way, the U-shaped tongue 6a is formed on the hinge spring 6 by stamping, and this tongue 6a is passed through the engaging hole 3b formed in the yoke 3 and is made to engage with it; further, the dish-shaped portion 6b provided on the hinge spring 6 is fitting into the fitting recess formed in the yoke 3 with the protrusion 3d provided on the yoke 3 being fitting into center hole 6c of the dish-shaped portion 6d of the hinge spring 6, to join the hinge spring 6 to the yoke 3. The dish-shaped portion 6b of the hinge spring 6 and its mating fitting recess 3a of the yoke 3 and the hole 6c of the hinge spring 6 and its mating protrusion of the yoke 3 need not necessarily be formed circular in shape, but it will be appreciated that these can be formed in various other shapes (for example, rectangular). As is apparent from the above description the assembling of the hinge spring to the yoke in the electromagnetic relay is accomplished by a simple part-to-part joining structure that does not require specific assembling equipment. This structure serves to simplify the assembly process and drastically reduce the number of assembling steps required.

Claims: An electromagnetic relay comprising: an iron core (1); an armature (2); a coil (12) wound around said iron core; a yoke (3), fastened rigidly to said iron core (1), having an engaging hole (3b) and a fitting portion (3a, 3d); a hinge spring (6) for supporting said armature (2) rotatably on said yoke (3); and a joining structure for joining said hinge spring (6) to said yoke (3) in said electromagnetic relay, characterised in that : said hinge spring (6) includes a tongue (6a) and a dish-shaped portion (6b); said engaging hole (3b) and fitting portion (3a, 3d) being provided for engaging with said tongue (6a) and said dish-shaped portion (6b) respectively, so that during assembly said hinge spring (6) is joined to said yoke (3) by inserting and fitting said hinge spring (6) into said yoke (3). An electromagnetic relay, as claimed in claim 1, wherein said dish-shaped portion (6b) of said hinge spring (6) includes a center hole (6c), and said fitting portion of said yoke (3) includes a recessed part (3a) and a raised part (3d) corresponding to said center hole (6c) of said dish-shaped portion (6b). An electromagnetic relay, as claimed in claim 2, wherein said recessed part (3a) and said raised part (3d) of said fitting portion engaged with said hinge spring (6) on said yoke (3) is formed with a plate thickness of said yoke (3). An electromagnetic relay, as claimed in any of claims 1 to 3, wherein said dish-shaped portion (6b) is formed as a circular shape. An electromagnetic relay, as claimed in any of claims 1 to 4, wherein said tongue (6a) of said hinge spring (6) is formed as a U-shape.

Inventors: NAKABAYASHI TAKAHIRO, TAKAHATA MASAKI, TAKANO SATOSHI, YOSHINO KOSEI, NAKABAYASHI, TAKAHIRO, TAKAHATA, MASAKI, TAKANO, SATOSHI, YOSHINO, KOSEI
Applicants: TAKAMISAWA ELECTRIC CO, TAKAMISAWA ELECTRIC CO., LTD.
Application year: 1998
Main classification: H01H50
IPC codes: H01H50