The invention relates to a switch device including a plurality of lead frames that is conductive and configured to be electrically connectable to an external device, a contact-separation mechanism configured to allow the plurality of lead frames to be electrically connected to and separated from each other, and an electric element configured to connect the plurality of lead frames to each other, and a method for manufacturing such a switch device.
For example, there is widely used a switch device that is incorporated in an external apparatus such as an electric component of an automobile and connects or separates an electrical connection of the external device. As such a switch device, Patent Document 1 discloses a switch device capable of detecting whether a connection between an external apparatus and an electric wire is in a normal state or a disconnection or short-circuit failure state by detecting a resistance value of a detection circuit. In the switch device disclosed in Patent Document 1, a resistor attached to a holding member (base) by soldering is accommodated in a case together with components such as a coil spring and a movable contact.
However, in the switch device disclosed in Patent Document 1, since the attached resistor is accommodated in the case in an exposed state, there is a possibility that reliability of a solder joint is lowered due to deterioration such as corrosion of the solder joint due to an influence of moisture in the surrounding air, a sulfide gas, and the like.
The invention has been made in view of such circumstances, and an object of the invention is to provide a switch device capable of maintaining reliability.
Another object of the invention is to provide a method for manufacturing such a switch device.
In order to solve the above problem, a switch device disclosed herein includes a plurality of lead frames that is conductive and configured to be electrically connectable to an external device, a contact-separation mechanism configured to allow the plurality of lead frames to be electrically connected to and separated from each other, and an electric element configured to connect the plurality of lead frames to each other, in which the electric element is surface-mounted on the plurality of lead frames and sealed with resin.
Further, the switch device further includes a casing accommodating a part or all of the plurality of lead frames, the contact-separation mechanism, and the electric element that is sealed with resin on the plurality of lead frames.
In the switch device, the electric element is a single electric element.
In the switch device, the electric element is a plurality of electric elements.
In the switch device, the plurality of electric elements has a substantially rectangular shape, and is arranged side by side on the plurality of lead frames in a manner in which long sides of one electric element are parallel to those of other electric element.
In the switch device, each of the lead frames includes a boundary disposed along an outer edge of an arrangement position of the electric elements.
Furthermore, a method for manufacturing a switch device including a plurality of lead frames that is conductive and configured to be electrically connectable to an external device, a contact-separation mechanism configured to allow the plurality of lead frames to be electrically connected to and separated from each other, and an electric element configured to connect the plurality of lead frames to each other, the method including a pressing step of forming the lead frames from a conductive plate, a placing step of placing the electric element on the plurality of lead frames formed in the pressing step, a resin sealing step of sealing, with resin, the electric element placed in the placing step and, thus, forming a mold body, and an assembling step of assembling components including the contact-separation mechanism and the mold body formed in the resin sealing step.
In the switch device and the method for manufacturing the switch device disclosed herein, the electric element is sealed with resin.
In the switch device and the method for manufacturing the switch device of the invention, the electric element surface-mounted on the lead frames is sealed with resin. This prevents, for example, deterioration such as corrosion due to an influence of moisture in the air, a sulfurized gas, and the like, maintains reliability of a solder joint, and exhibits other excellent effects.
Hereinafter, an embodiment of the invention will be described with reference to the drawings.
A switch device of the invention is used for various products and applications including an electrical system or the like of a vehicle such as an automobile and a motorcycle. Specific examples of the switch device include a latch switch that detects an opening and closing state of a door of an automobile. Further, the invention is not limited to automobiles and motorcycles, and is used for various industrial detection switches and the like. Hereinafter, an example of a switch device including one or a plurality of electric elements will be described with reference to the drawing describing such a switch device as a switch device 1.
<Switch Device 1>
The switch device 1 includes a casing 10 having a substantially rectangular parallelepiped shape, and has a substantially rectangular parallelepiped outer shape as a whole by accommodating various members in the casing 10. A lower surface of the casing 10 having a substantially rectangular parallelepiped shape is opened, and a lower surface of a mold body 13 accommodated and integrated in the casing 10 is a lower surface of the switch device 1. On an upper surface of the casing 10, a movable member 11 that can be pushed into the casing 10 by receiving pressure from outside is inserted into a position on the left side with respect to a center in front view. The movable member 11 is a shaft having a substantially columnar shape, and is inserted into an insertion hole (not illustrated) opened in the upper surface of the casing 10.
Two terminals 12 connected to an external device protrude from a position on the left side and a vicinity of the center of the lower surface of the mold body 13 included in the switch device 1. In the following description, when the protruding terminals 12 are particularly distinguished, the terminal 12 on the left side will be referred to as a first terminal 12a, and the terminal 12 near the center will be referred to as a second terminal 12b. When the switch device 1 is used as the switch device 1 having the A contact specification, for example, the first terminal 12a is a COM terminal, and the second terminal 12b is an N.O. terminal. Further, when the switch device 1 is used as the switch device 1 having the B contact specification, the terminal 12 serving as an N.C. terminal can be provided. Which terminal 12 is used as the COM terminal, the N.O. terminal, or the N.C. terminal can be appropriately designed in accordance with the circuit configuration in the switch device 1 or a design of an external device or the like.
In the casing 10 of the switch device 1, components such as a lead frame 16 and an electric element 17 (see
In the switch device 1 thus formed, when the movable member 11 is pressed downward, the movable member 11 moves downward against a biasing force of the biasing member 14, presses the movable contact 15 attached to the movable member 11, and moves the movable contact 15 to change an open and close state of the electric circuit in the switch device 1. When the pressing of the movable member 11 is released, the movable member 11 moves upward by the biasing force of the biasing member 14, the movable contact 15 attached to the movable member 11 returns to a state before the pressing, and the open and close state of the electric circuit in the switch device 1 is returned to an original state. Note that in the change in the open and close state of the electric circuit by the movable contact 15, the electric circuit can be closed in response to pressing of the movable member 11 or can be opened.
The lead frame 16 is obtained by molding a conductive metal plate by a molding method such as press working, and a part of the lead frame 16 is molded as the terminal 12 connected to an external device. In the examples in
The first lead frame 16a is provided with portions such as a first fixed contact 16a1 and a first placing portion 16a2 in addition to the first terminal 12a. The first fixed contact 16a1 functions as a part of the contact-separation mechanism, and is electrically connected to and separated from the movable contact 15 in accordance with operation of the movable contact 15. The electric element 17 can be surface-mounted on the first placing portion 16a2, and is a portion to which solder is applied in order to attach the electric element 17.
The second lead frame 16b is provided with a portion such as a second placing portion 16b1 in addition to the second terminal 12b. The electric element 17 can be surface-mounted on the second placing portion 16b1, and is a portion to which solder is applied in order to attach the electric element 17.
The third lead frame 16c is provided with portions such as a second fixed contact 16c1 and a third placing portion 16c2. The second fixed contact 16c1 functions as a part of the contact-separation mechanism, and is always in electrical contact with the movable contact 15 regardless of the operation of the movable contact 15. Thus, the first fixed contact 16a1 and the second fixed contact 16c1 are electrically connected to and separated from each other by the operation of the movable contact 15. The electric element 17 can be surface-mounted on the third placing portion 16c2, and is a portion to which solder is applied in order to attach the electric element 17. One or two electric elements 17 can be attached to the third placing portion 16c2.
The electric element 17 is a surface mounting type element using one element or a plurality of elements such as a resistor and a capacitor, and is molded in a flat substantially rectangular parallelepiped shape. A mode exemplified in
The first electric element 17a and the second electric element 17b having substantially rectangular parallelepiped shapes are arranged side by side on the lead frame 16 in a manner in which long sides of one electric element are parallel to those of other electric element. The lead frame 16 is provided with a boundary 160 such as a groove or a notch along an outer edge of an arrangement position of the electric element 17. For example, in the first lead frame 16a, a groove is formed in an upper part of the first placing portion 16a2. Further, in the third lead frame 16c, a groove is formed in an upper part of the third placing portion 16c2. Further, in the third placing portion 16c2 of the third lead frame 16c, a notch is formed between an arrangement position of the first electric element 17a and an arrangement position of the second electric element 17b. When solder such as cream solder is applied to the placing portion by forming the boundary 160 such as a groove or a notch in the lead frame 16, the solder can be prevented from flowing beyond the boundary 160 due to surface tension of the applied solder. Note that it is also possible to form the boundary 160 as a wall protruding from the lead frame 16.
<Method for Manufacturing Switch Device 1>
Next, a method for manufacturing the switch device 1 disclosed herein will be described.
After the pressing step, a boundary formation step of forming the boundary portion 160 such as a groove or a notch is performed on the punched prototype of the lead frame 16 (step S2).
After the boundary formation step, a chip placing step of placing the surface mount type electric element 17 on the lead frame 16 and soldering the electric element 17 is performed (step S3). The chip placing step is a step of applying cream solder to the placing portion on which the electric element 17 is to be placed among the first placing portion 16a2, the second placing portion 16b1, and the third placing portion 16c2, and soldering the placing portion by reflow. The boundary 160, which is formed prior to the application of the solder cream, can prevent the solder cream from flowing out.
After the chip placing step, a resin sealing step of sealing (molding) the electric element 17 placed on the lead frame 16 with resin and, thus, forming the mold body 13 is performed (step S4).
After the resin sealing step, a cutting step of cutting the lead frame 16 connected to the frame bar and cutting off the lead frame, together with the integrated mold body 13, from the frame bar is performed (step S5). In the cutting step, an unnecessary terminal 12 is also cut.
In the flowchart of
<Circuit Configuration of Switch Device 1>
Next, an example of the circuit configuration of the switch device 1 will be described.
Example 1 has a configuration of the A contact specification in which the second placing portion 16b1 and the third placing portion 16c2 are bridged by the second electric element 17b including a resistor R1, the third terminal 12c is cut, the first terminal 12a is a COM terminal, and the second terminal 12b is an N.O. terminal. By measuring a resistance value between the COM terminal and the N.O. terminal in the drawing, it is possible to detect a short circuit of an external device connected to the switch device 1. In a normal state, when the movable member 11 is opened, the circuit is in an open state and the resistance value is a resistance at time of opening, that is, substantially infinite. When the movable member 11 is pressed, the circuit is in a closed state, and the resistance value is R1. When a short circuit occurs, the resistance value is a resistance value at time of short circuit (the resistance value varies depending on a site of the short circuit). Therefore, the short circuit can be detected by measuring the resistance value.
Example 2 has a configuration in which the first placing portion 16a2 and the third placing portion 16c2 are bridged by the first electric element 17a including the resistor R1, the second placing portion 16b1 and the third placing portion 16c2 are bridged by a jumper wire not including the electric element 17, and the third terminal 12c is cut. Example 2 has a configuration of the A contact specification in which the first terminal 12a is a COM terminal and the second terminal 12b is an N.O. terminal. By measuring a resistance value between COM and N.O. in the drawing, it is possible to detect disconnection of an external device connected to the switch device 1. In the normal state, when the movable member 11 is opened, the circuit is in an open state, and the resistance value is R1. When the movable member 11 is pressed, the circuit is in a closed state, and the resistance value is a resistance value Rsw (Rsw<<R1) of a switch SW (contact-separation mechanism). When a disconnection occurs, the resistance value is a resistance in an open state, that is, infinite. Therefore, the disconnection can be detected by measuring the resistance value.
Example 3 has a configuration in which the first placing portion 16a2 and the third placing portion 16c2 are bridged by the first electric element 17a including the resistor R1, the second placing portion 16b1 and the third placing portion 16c2 are bridged by the second electric element 17b including the resistor R2, and the third terminal 12c is cut. Example 3 has a configuration of the A contact specification in which the first terminal 12a is a COM terminal and the second terminal 12b is an N.O. terminal. By measuring a resistance value between COM and N.O. in the drawing, it is possible to detect a short circuit and a disconnection of an external device connected to the switch device 1. In the normal state, when the movable member 11 is opened, the circuit is in an open state, and the resistance value is R1+R2. When the movable member 11 is pressed, the circuit is in a closed state, and the resistance value is R2. When a short circuit occurs, the resistance value is the resistance value at the time of short circuit. Further, when a disconnection occurs, the resistance value is a resistance in an open state, that is, infinite. Therefore, a short circuit and disconnection can be detected by measuring the resistance value.
The switch device 1 disclosed herein can be configured not only as the switch device 1 having the A contact specification described with reference to
In the circuit configuration, various circuits can be formed by appropriately designing a shape and connection form of the lead frame 16.
Next, an example in which the above circuit configuration is connected to an external device, such as an electric system of an automobile, and a state of the circuit is detected by a detection voltage will be described.
In the circuit illustrated in
As described above, the detection voltage Signal takes a value of about 5 V or about 8 V depending on the open or close state of the circuit in the normal state, and takes either a value of 0 V in a short-circuit state or a value of 12 V in a disconnection state. In this way, the open and close state of the switch device 1 and the state of the external device can be detected by the detection voltage Signal.
As described above, since the electric element 17 is surface-mounted on the lead frame 16 and is sealed with resin, the switch device 1 disclosed herein prevents deterioration such as corrosion due to the influence of moisture in the external atmosphere, sulfurized gas, and the like, maintains the reliability of the solder joint, and exhibits other excellent effects.
Further, as the boundary 160, such as a groove or a notch, is formed in the lead frame 16 along the outer edge of the arrangement position of the electric element 17, the switch device 1 disclosed herein can prevent the applied solder from flowing out, prevent deterioration of yield, and exhibit other excellent effects.
Further, in the switch device 1 disclosed herein, one or a plurality of electric elements 17 can be surface-mounted on the lead frame 16. Furthermore, the plurality of rectangular parallelepiped electric elements 17 is arranged side by side on the lead frame 16 in a manner in which long sides of one electric element are parallel to those of other electric element, and thus the switch device 1 disclosed herein is miniaturized and has other excellent effects.
Since the lead frame 16 is formed in a planar shape, the switch device 1 disclosed herein facilitates processing, simplifies steps, and exhibits other excellent effects.
The invention is not limited to the embodiments described above, and can be implemented in various other modes. Thus, the above embodiments are merely examples in all respects, and should not be construed in a limited manner. The technical scope of the invention is described by the claims, and is not restricted by the description at all. Furthermore, all modifications and changes falling within the equivalent scope of the claims are within the scope of the invention.
For example, in the above embodiment, the electric element 17 is surface-mounted on one surface side of the lead frame 16. However, the invention is not limited to this configuration, and can be developed into various modes. For example, the electric elements 17 can be surface-mounted on both surfaces of the lead frame 16. When the electric elements 17 are provided on both surfaces of the lead frame 16, it is possible to increase a degree of freedom in designing the circuit configuration, and it is possible to suppress the current flowing through one electric element 17 by arranging the electric elements 17 in parallel. By suppressing the current flowing through one electric element 17, the current flowing through the entire circuit can be increased and the electric element 17 having a low durable current can be used.
Number | Date | Country | Kind |
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2019-047347 | Mar 2019 | JP | national |
Filing Document | Filing Date | Country | Kind |
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PCT/JP2020/011141 | 3/13/2020 | WO | 00 |