ELECTRONIC DEVICE

Abstract

An electronic device (1) comprises a housing (31) with a first opening (31a) containing an electronic component and a discharge resistor, a discharge switch (21), a first cover (32) that is openable and closable and covers the first opening (31a), and a displacement limiting element (35). The discharge switch (21) has a pair of terminals (22a, 22b) and a movable element (23) made of a conductor, which is arranged in a conductive or a non-conductive position. The displacement limiting element (35) allows the movable element (23) to be in the conductive position when the first cover (32) is open and holds the movable element (23) in the non-conductive position when the first cover (32) is closed.When the movable element (23) is in the conductive position, the electronic component is electrically connected to the discharge resistor, and when the movable element (23) is in the non-conductive position, the electronic component is electrically separated from the discharge resistor.

Description

Technical field

[0001] The present disclosure relates to an electronic device. Technical background

[0002] An electronic device, such as a drive control unit or a power supply unit installed in a rail vehicle, has a housing that contains electronic components. To enable safe maintenance work on the electronic components, some electronic devices have structures that suppress the power supply to the electronic devices when the housing covers are opened. Examples of such electronic devices are disclosed in patent literature 1. List of patent literature

[0003] Patent literature 1: Unexamined Japanese utility model application Publication No. H4-76530 Brief description of the invention: Technical problem

[0004] The electronic device disclosed in patent literature 1 comprises a microswitch that switches on and off in response to the opening and closing of the housing cover, and a relay arranged in an electrical circuit for raising the pantograph, which switches between an on and an off state depending on the state of the microswitch. When the cover is opened, the relay switches to the off state and electrically disconnects the main circuit from the power supply. This ensures that even if a pantograph raising switch is accidentally activated during maintenance work, no power is supplied to the electronic device.

[0005] To further ensure safety during maintenance of the main circuit in the electronic device disclosed in patent literature 1, high-voltage electronic components in the main circuit, such as a capacitor, must be discharged before maintenance. This is done with the cover open and the main circuit electrically disconnected, as described above. To further increase the safety of the electronic device, a switch can be provided that electrically connects the capacitor to a discharge resistor when the electronic device is switched off, thus ensuring that the capacitor is discharged. The switch is, for example, designed as an electronically controlled switch. However, a malfunction of the electronically controlled switch could prevent the capacitor from being connected to the discharge resistor and therefore from being discharged before maintenance.

[0006] Under these circumstances, one objective of the present disclosure is to provide a highly secure electronic device. Solution to the problem

[0007] To achieve the aforementioned objective, an electronic device according to the present disclosure comprises a housing, a discharge switch, a first cover, and a displacement limiting element. The housing has a first opening. The housing accommodates an electronic component and a discharge resistor for discharging the electronic component. The discharge switch is included in the housing and has a pair of terminals and a movable element. One of the terminals is electrically connected to the electronic component, and the other terminal is electrically connected to the discharge resistor.The movable element is made of a conductor and is arranged either in a conductive position, where the movable element is in contact with both of the pair of terminals, or in a non-conductive position, where the movable element is spaced away from at least one of the pair of terminals. The first cover is openable and closeable and covers the first opening. The displacement limiting element allows the movable element to be in the conductive position when the first cover is open and holds the movable element in the non-conductive position when the first cover is closed.When the movable element of the discharge switch is in the conductive position, the electronic component is electrically connected to the discharge resistor, and when the movable element of the discharge switch is in the non-conductive position, the electronic component is electrically isolated from the discharge resistor. Advantageous effects of the invention

[0008] The displacement limiting element included in the electronic device of the present disclosure enables the movable element to be positioned in the conductive position when the first cover is open. This results in the electronic component being electrically connected to the discharge resistor when the first cover is open. This allows the electronic device to exhibit a high level of safety. Brief description of the drawings Fig. Figure 1 shows a circuit diagram of an electronic device according to embodiment 1; Fig. Figure 2 shows a perspective view of the electronic device according to embodiment 1; Fig. Figure 3 shows a diagram illustrating a displacement limiting element and a discharge switch according to embodiment 1, wherein the discharge switch is in an on state; Fig. Figure 4 shows a diagram illustrating the displacement limiting element and the discharge switch according to embodiment 1, wherein the discharge switch is in an off state; Fig. Figure 5 shows a perspective view of the discharge switch according to embodiment 1; Fig. Figure 6 shows a perspective view of a discharge switch according to embodiment 2, wherein the discharge switch is in an off state; Fig. Figure 7 shows a perspective view of the discharge switch according to embodiment 2, wherein the discharge switch is in an on state; Fig. Figure 8 shows a perspective view of a housing according to embodiment 3; Fig. Figure 9 shows a perspective view of an electronic device according to embodiment 3; Fig. Figure 10 shows a diagram illustrating a displacement limiting element, a discharge switch and a key holder according to embodiment 3, wherein the discharge switch is in an on state; Fig. Figure 11 shows a diagram illustrating a displacement limiting element, a discharge switch and a key holder according to embodiment 3, wherein the discharge switch is in an off state; Fig. Figure 12 shows a diagram illustrating a modified example of a displacement limiting element, a discharge switch and a key holder included in a first modified example of an electronic device according to an embodiment, wherein the discharge switch is in an on state; Fig. Figure 13 shows a diagram illustrating a modified example of the displacement limiting element, the discharge switch, and the key holder included in the first modified example of the electronic device according to the embodiment, wherein the discharge switch is in an off state; and Fig. Figure 14 shows a diagram illustrating a modified example of a displacement limiting element, a discharge switch and a key holder included in a second modified example of the electronic device according to the embodiment. Description of embodiments

[0009] An electronic device according to one or more embodiments of the present disclosure is described in detail below with reference to the drawings. In the drawings, identical or equivalent components are identified by the same reference numerals. Design 1

[0010] A direct current (DC) three-phase converter is installed as an example of an electronic device in a rail vehicle to convert direct current supplied by a DC source into three-phase alternating current (AC) and supply the AC to a motor. An electronic device 1 according to embodiment 1 is described using the DC three-phase AC power converter as an example. The electronic device 1, which is installed in Fig. The electronic device shown in Figure 1 is installed in a rail vehicle connected to a DC power supply system. The electronic device 1 converts the supplied DC power into AC power, which is supplied to a load device 91, and delivers the converted AC power to the load device 91. The load device 91 is, for example, a three-phase asynchronous motor that generates the propulsion of the rail vehicle.

[0011] The in Fig. The electronic device 1 shown in Figure 1 has an input terminal 1a, which is to be connected to a power source, and an input terminal 1b, which is to be grounded. The electronic device 1 further has a power conversion circuit 11, which converts direct current power supplied by a power source into alternating current power, a capacitor C1, which is connected between the input terminals 1a and 1b, and a discharge circuit 12, which is connected in parallel with the capacitor C1. The discharge circuit 12 has a switching element SW1 and a discharge resistor R1, which are connected in series, as well as a discharge switch 21 and a discharge resistor R2, which are also connected in series.

[0012] Input terminal 1a is connected to a power source, in particular a current collector, via, for example, a contactor or a coil (not shown). The current collector receives power from a substation via a power supply line. The current collector is, for example, a pantograph or a current collector shoe, and the power supply line is an overhead line or a third rail. Input terminal 1b is short-circuited and grounded via, for example, a grounding brush, a grounding ring, or a wheel (not shown).

[0013] Capacitor C1 is located between the primary terminals of the power conversion circuit 11 and is charged by the direct current supplied by the power source. Capacitor C1 and the inductor (not shown) together act as an LC filter to reduce the harmonic components generated by the switching operation of the power conversion circuit 11.

[0014] The power conversion circuit 11 converts the direct current supplied via capacitor C1 into three-phase alternating current and outputs the three-phase alternating current to the load device 91. The voltage and frequency of the three-phase alternating current output by the power conversion circuit 11 are adjustable. The power conversion circuit 11 incorporates a variety of switching elements, such as insulated-gate bipolar transistors (IGBTs), gate-switched thyristors (GTOs), or metal-oxide-semiconductor field-effect transistors (MOSFETs).

[0015] The multitude of switching elements present in the power conversion circuit 11 are controlled by control signals provided by a power conversion control device (not shown) and switch on and off. The multitude of switching elements performs switching operations to carry out the power conversion in the power conversion circuit 11.

[0016] Switching element SW1 and discharge resistor R1 are connected in parallel with capacitor C1. Switching element SW1 is electrically controlled by a switching controller (not shown). For example, switching element SW1 has a similar configuration to the switching elements in power conversion circuit 11. Switching element SW1 is controlled by a control signal output by the switching controller and switches on and off.

[0017] When switching element SW1 is activated, the discharge resistor R1 is electrically connected to capacitor C1, and capacitor C1 is discharged. When switching element SW1 is deactivated, the discharge resistor R1 is electrically disconnected from capacitor C1. For example, the switching control activates switching element SW1 when the voltage between the terminals of capacitor C1 reaches an overvoltage, in order to discharge capacitor C1. When the voltage between the terminals of capacitor C1 is then within a target voltage range, the switching control deactivates switching element SW1. This electrically disconnects capacitor C1 from the discharge resistor R1.

[0018] The discharge switch 21 and the discharge resistor R2 are connected in parallel with the capacitor C1. The discharge switch 21 is mechanically switched on and off. When the discharge switch 21 is switched on, the discharge resistor R2 is electrically connected to the capacitor C1, and the capacitor C1 is discharged. When the discharge switch 21 is switched off, the discharge resistor R2 is electrically disconnected from the capacitor C1.

[0019] The structure of electronic device 1 is described in detail below. As in Fig. As shown in Figure 2, the electronic device 1 has a housing 31 which contains an electronic component that is part of the electronic device 1 according to Fig. 1, as well as the discharge resistors R1 and R2 for discharging a capacitor C1, which represents an example of the electronic component. The housing 31 has a first opening 31a, which allows maintenance work on the component of the electronic device 1.

[0020] The electronic device 1 further comprises a first cover 32, which is openable and closable and covers the first opening 31a, as well as a cooling device 81, which is thermally connected to the electronic components housed inside the casing 31 and which generate heat when current is supplied. The cooling device 81 cools the electronic components by dissipating the heat emitted by the components to the ambient air.

[0021] In Fig. Figure 2 shows the Z-axis in the vertical direction. The direction in which the first opening 31a extends is defined as the Y-axis. The axis perpendicular to both the Z-axis and the Y-axis is defined as the X-axis. This also applies to the following figures. For example, the electronic device 1 is mounted under the floor of the rail vehicle by means of a suspension device (not shown), with the Y-axis aligned with the lateral direction and the X-axis with the direction of travel of the rail vehicle.

[0022] The housing 31 has the first opening 31a on the side surface, more precisely on a surface that points in the direction of the negative Y-axis.

[0023] The first cover 32 rotates about a rotation axis AX1, which runs parallel to the Z-axis, and thereby opens or closes the first opening 31a. The first cover 32 consists of a plate-shaped material that can cover the entire first opening 31a and the surrounding area.

[0024] The cooling device 81, for example, comprises a heat-absorbing block that is thermally connected to the electronic components inside the housing 31, fins attached to the heat-absorbing block and exposed outside the housing 31, and a cover that covers the heat-absorbing block and the fins and has ventilation openings. The heat generated by the electronic components is transferred via the heat-absorbing block and the fins to the air that flows into the interior of the cover through the ventilation openings, thereby cooling the electronic components.

[0025] The structure for increasing the security of the electronic device 1 is described in detail below. Fig. 3 and Fig. Figure 4 shows the electronic device 1 from inside the housing 31 towards the first cover 32. For simplicity, they show Fig. 3 and Fig. 4 only the discharge switch 21 among the components of the electronic device 1, which are housed inside the casing 31. With the first cover 32 open, as shown in Fig. As shown in 3, the discharge switch 21 is switched on. As in Fig. As shown in Figure 4, the discharge switch 21 is switched off when the first cover 32 is closed.

[0026] The discharge switch 21 has a pair of terminals 22a and 22b and a movable element 23, which is arranged in a conductive or a non-conductive position. Preferably, the discharge switch 21 further has a biasing element 24 that biases the movable element 23 into the conductive position. The discharge switch 21 further has a terminal retaining element 25 that retains the pair of terminals 22a and 22b.

[0027] The electronic device 1 further comprises a mounting frame 33, which is attached to an inner surface of the housing 31, and a support element 34, which is attached to the mounting frame 33 and supports the discharge switch 21. The electronic device 1 further comprises a displacement limiting element 35, which allows the movable element 23 to be in the conductive position when the first cover 32 is open, and to be held in the non-conductive position when the first cover 32 is closed.

[0028] As in Fig. Figure 5, which shows a perspective view of the discharge switch 21, shows that in embodiment 1, the terminals 22a and 22b each have a shape that clamps the movable element 23 in the Z-axis. One of the terminals 22a and 22b is electrically connected to the electronic component to be discharged, i.e., the capacitor C1. The other of the terminals 22a and 22b is electrically connected to the discharge resistor R2. In embodiment 1, one of the terminals 22a and 22b is electrically connected to a connection point between the input terminal 1a and the Fig. 1 is connected to the power conversion circuit 11 shown, and the other of the terminals 22a and 22b is electrically connected to the discharge resistor R2.

[0029] The movable element 23 consists of a conductor. In embodiment 1, the movable element 23 is made of a plate-shaped metal part. The movable element 23 is in the conductive position in which it is in contact with both terminals 22a and 22b, as shown in Fig. 3 and Fig. 5 shown, or in the non-conductive position in which it is spaced away from at least one of the terminals 22a and 22b, as shown in Fig. 4 shown. In embodiment 1, as in Fig. Figure 5 shows one end of the movable element 23 fixed to the terminal 22b by a fastening element. The movable element 23 rotates about a rotation axis AX2, which runs parallel to the Z-axis, with one end fixed to the terminal 22b.

[0030] The discharge switch 21 has a pair of preload elements 24 positioned such that the movable element 23 is located between the pair of preload elements 24 along the Z-axis. The preload elements 24 preload the movable element 23 into the conducting position. In embodiment 1, the preload elements 24 consist of an elastic body that deforms under external force and returns to its original shape when the external force is removed. The movable element 23 is in the conducting position when the elastic body has returned to its original shape. Specifically, the preload elements 24 consist of a helical spring, one end of which is attached to the terminal retaining element 25 and the other end of which is attached to the movable element 23 via an insulating element 26. When the helical spring is in its natural length, the movable element 23 is in the conducting position.Does the movable element 23 rotate clockwise from the position in . Fig. 5. Viewed in the positive Z-axis direction, in the non-conducting position, the preload element 24, consisting of the coil spring, generates a force in the direction of returning to its natural length. In other words, the preload elements 24 pull the movable element 23 from the non-conducting position towards the conducting position. This forces the movable element 23 from the non-conducting position towards the conducting position.

[0031] The terminal retaining element 25 keeps terminals 22a and 22b isolated from each other. The terminal retaining element 25 is made of an insulating material, for example, plastic.

[0032] As in Fig. 3 and Fig. As shown in Figure 4, the mounting frame 33 is attached to the inner surface of the housing 31 and is in contact with it. The mounting frame 33 has such high stiffness and strength that it can withstand deformations caused by the maximum expected vibrations of the rail vehicle. For example, the mounting frame 33 is made of a metal part, such as iron or aluminum. The mounting frame 33 can be so firmly connected to the housing 31 that a constant position relative to the housing 31 is maintained even under the vibrations of the moving rail vehicle. The mounting frame 33 is attached to the housing 31 by a fastening method such as fastening with a fastener, adhesive bonding, welding, or brazing.

[0033] The support element 34 exhibits such high stiffness and strength that it can withstand deformation caused by the maximum expected vibrations of the rail vehicle. For example, the support element 34 is made of a metal component, such as iron or aluminum. The support element 34 can be so firmly connected to the mounting frame 33 that a constant position relative to the mounting frame 33 is maintained even under the vibrations of the moving rail vehicle. The support element 34 is attached to the mounting frame 33 using a fastening method such as fastening with a fastener, adhesive bonding, welding, or brazing.

[0034] The connection-holding element 25 in the discharge switch 21 is attached to the support element 34. The connection-holding element 25 can be attached to the support element 34 so firmly that a constant position relative to the support element 34 is maintained even under the vibrations of the moving rail vehicle. For example, the connection-holding element 25 is attached to the support element 34 with a fastening element.

[0035] The displacement limiting element 35 has a contact section 35a with a plate-like shape, which is attached to one side of the first cover 32 that faces an interior of the housing 31 and extends in a direction away from the first cover 32. The displacement limiting element 35 has such high stiffness and strength that it can withstand deformation caused by the maximum expected vibrations of the rail vehicle. For example, the displacement limiting element 35 is made of a metal part, such as iron or aluminum. The displacement limiting element 35 can be attached so firmly to the first cover 32 that a constant position relative to the first cover 32 is maintained even under the vibrations of the moving rail vehicle.The displacement limiting element 35 is attached to the first cover 32 by a fastening method, such as fastening with a fastener, adhesive bonding, welding or brazing. The displacement limiting element 35 is preferably insulated.

[0036] As in Fig. As shown in Figure 4, when the first cover 32 is closed, the contact section 35a of the displacement limiting element 35 comes into contact with the movable element 23 and pushes the movable element 23 in the direction of the positive Y-axis. This causes the movable element 23 to rotate about the rotation axis AX2, with one end fixed at terminal 22b, and to move away from terminal 22a. Consequently, the movable element 23 is in the non-conductive position. When the first cover 32 is closed, the displacement limiting element 35 holds the movable element 23 in the non-conductive position.

[0037] During operation of the rail vehicle, the power conversion circuit 11 performs power conversion by switching a multitude of switching elements within the power conversion circuit 11. When the operation of the rail vehicle stops, that is, when the operation of the electronic device 1 ceases, the power conversion controller switches off the multitude of switching elements of the power conversion circuit 11. Subsequently, the switching controller switches on switching element SW1, thereby electrically connecting and discharging capacitor C1 with discharge resistor R1.

[0038] Maintenance work on electronic equipment 1 is carried out with electronic equipment 1 stopped. During maintenance work, when the first cover 32 is removed as shown in Fig. As shown in Figure 3, when the opening is activated, the contact section 35a of the displacement limiting element 35 moves away from the movable element 23 while the first cover 32 rotates. This causes the biasing element 24 to advance the movable element 23 from the non-conductive position to the conductive position. Consequently, the movable element 23 comes into contact with terminals 22a and 22b, and the discharge switch 21 is activated. When the discharge switch 21 is activated, capacitor C1 is electrically connected to the discharge resistor R2 and discharged. This allows capacitor C1 to be discharged via the discharge resistor R2 even if capacitor C1 cannot be discharged via the discharge resistor R1 due to a failure of the switching element SW1.

[0039] As described above, the displacement limiting element 35 present in the electronic device 1 according to embodiment 1 allows the movable element 23 to be moved into the conductive position when the first cover 32 is opened. The discharge switch 21 is then activated, and the capacitor C1 is electrically connected to the discharge resistor R2 and discharged. In other words, when the first cover 32 is opened, the discharge switch 21 is activated by mechanical actuation, allowing the capacitor C1, which is subjected to a high voltage, to be discharged.Even if the capacitor C1 cannot be discharged via the discharge resistor R1 due to a failure of the switching element SW1, the activation of the discharge switch 21 by the mechanical actuation (opening of the first cover 32) allows the capacitor C1 to be discharged via the discharge resistor R2, thus ensuring the safety of the maintenance work. Design 2

[0040] The structure of the discharge switch is not limited to the example mentioned above, but can have any structure that is in the off state when the first cover 32 is closed and in the on state when the first cover 32 is open. The electronic device 1 with a discharge switch having a structure different from that of embodiment 1 is described in embodiment 2.

[0041] The electronic device 1 according to embodiment 2 has a discharge switch 51 which is located in Fig. 6 and Fig. Figure 7 shows the structure of the electronic device 1, apart from the discharge switch 51, corresponds to that of embodiment 1. The discharge switch 51 is connected in series with the discharge resistor R2. The discharge switch 51 and the series-connected discharge resistor R2 are connected in parallel with the capacitor C1.

[0042] The discharge switch 51 is switched on and off by mechanical actuation. When the discharge switch 51 is switched on, the discharge resistor R2 is electrically connected to the capacitor C1, and the capacitor C1 is discharged. When the discharge switch 51 is switched off, the discharge resistor R2 is electrically disconnected from the capacitor C1.

[0043] The discharge switch 51 has a pair of terminals 52a and 52b, a movable element 53 which is arranged in the conductive or non-conductive position, and a biasing element 54 which biases the movable element 53 into the conductive position. The discharge switch 51 further has a terminal retaining element 55 which holds the pair of terminals 52a and 52b, and a holder for the movable element 56 which holds the movable element 53.

[0044] In embodiment 2, terminals 52a and 52b each have a column-like shape extending along the Y-axis. One of terminals 52a and 52b is electrically connected to the electronic component to be discharged, i.e., capacitor C1. The other terminal 52a and 52b is electrically connected to the discharge resistor R2. In embodiment 2, one of terminals 52a and 52b is electrically connected to a connection point between the input terminal 1a and the [unclear text]. Fig. 1 is connected to the power conversion circuit 11 shown, and the other of the terminals 52a and 52b is electrically connected to the discharge resistor R2.

[0045] The movable element 53 consists of a conductor. In embodiment 2, the movable element 53 is made of a metal part that has a columnar shape and extends in the Y-axis, as shown in Fig. Figure 6 shows that the movable element 53 has holes into which the terminals 52a and 52b are inserted. The movable element 53 is in the conductive position in which it is in contact with both terminals 52a and 52b, as shown in Figure 6. Fig. 7 shown, or in the non-conducting position, in which it is spaced apart from both terminals 52a and 52b, as in Fig. 6 shown.

[0046] The discharge switch 51 has a preload element 54 that extends along the Y-axis. The preload element 54 biases the movable element 53 into the conducting position. The preload element 54 consists of an elastic body that deforms under external force and returns to its original shape when the external force is removed. The movable element 53 is in the conducting position when the elastic body has returned to its original shape. Specifically, the preload element 54 consists of a helical spring, one end of which is attached to the terminal retaining element 55 and the other end of which is attached to the holder for the movable element 56. When the helical spring is at its natural length, the movable element 53 is in the conducting position, as shown in Fig. 7 shown.

[0047] If the holder for the movable element 56, which holds the movable element 53, moves from the position in Fig. When the movable element 53 is moved in the direction of the positive Y-axis and is in the non-conducting position, the preload element 54, consisting of the coil spring, generates a force in the direction of returning to its natural length. This pushes the holder for the movable element 56 in the direction of the negative Y-axis. In other words, the movable element 53 is pushed from the non-conducting position towards the conducting position.

[0048] The terminal retaining element 55 keeps the terminals 52a and 52b isolated from each other. The terminal retaining element 55 consists of an insulating material, for example, plastic. In embodiment 2, the terminal retaining element 55, as shown in Fig. Figure 6 shows a box-shaped form that opens in the direction of the positive Y-axis and accommodates the terminals 52a and 52b inside, spaced apart from each other. A mounting section 55a with a flat plate-shaped form and a main surface perpendicular to the Y-axis is provided on the side of the terminal retaining element 55 that faces in the direction of the positive X-axis. A mounting section 55b with a flat plate-shaped form and a main surface perpendicular to the Y-axis is provided on the side of the terminal retaining element 55 that faces in the direction of the negative X-axis.

[0049] The holder for the movable element 56 is made of an insulating material, for example, plastic. In embodiment 2, the holder for the movable element 56 has a box-shaped form that opens in the direction of the negative Y-axis and accommodates the movable element 53, with a portion of the movable element 53 exposed. A mounting section 56a with a flat, plate-like shape and a main surface perpendicular to the Y-axis is provided on the side of the holder for the movable element 56 that faces in the direction of the positive X-axis. A mounting section 56b with a flat, plate-like shape and a main surface perpendicular to the Y-axis is provided on the side of the holder for the movable element 56 that faces in the direction of the negative X-axis.

[0050] The preload element 54 is attached at one end to the mounting section 55a of the connecting retaining element 55 and at the other end to the mounting section 56a of the holder for the movable element 56. The holder for the movable element 56 is attached to the connecting retaining element 55 via an extension and retraction mechanism 57, which is extendable and retractable in the Y-axis. Specifically, the extension and retraction mechanism 57 has one end attached to the mounting section 55b of the connecting retaining element 55 and another end attached to the mounting section 56b of the holder for the movable element 56.

[0051] With the first cover 32 closed, the contact section 35a of the displacement limiting element 35 comes into contact with the mounting section 56a of the holder for the movable element 56 and pushes the holder for the movable element 56 in the direction of the positive Y-axis. As a result, the movable element 53 moves together with the holder for the movable element 56 in the direction of the positive Y-axis and away from both terminals 52a and 52b. In other words, the movable element 53 is in the non-conductive position. With the first cover 32 closed, the displacement limiting element 35 holds the movable element 53 in the non-conductive position.

[0052] During operation of the rail vehicle, the power conversion circuit 11 performs power conversion by switching a multitude of switching elements within the power conversion circuit 11. When the operation of the rail vehicle stops, that is, when the operation of the electronic device 1 ceases, the power conversion controller switches off the multitude of switching elements of the power conversion circuit 11. Subsequently, the switching controller switches on switching element SW1, thereby electrically connecting and discharging capacitor C1 with discharge resistor R1.

[0053] Maintenance work on the electronic device 1 is carried out with the electronic device 1 stopped. During the maintenance work, when the first cover 32 is opened, the contact section 35a of the displacement limiting element 35 moves away from the holder for the movable element 56 while the first cover 32 rotates. This causes the preloading element 54 to bias the holder for the movable element 56 in the direction of the negative Y-axis. As a result, the movable element 53, as shown in Fig. Figure 7 shows the capacitor being forced from the non-conductive position to the conductive position, making contact with both terminals 52a and 52b, and the discharge switch 51 is activated. When the discharge switch 51 is activated, the capacitor C1 is electrically connected to the discharge resistor R2 and discharged. This allows the capacitor C1 to be discharged via the discharge resistor R2 even if the capacitor C1 cannot be discharged via the discharge resistor R1 due to a failure of the switching element SW1.

[0054] As described above, the displacement limiting element 35 present in the electronic device 1 according to embodiment 2 enables the movable element 53 to be moved into the conductive position when the first cover 32 is opened. The discharge switch 51 is then activated, and the capacitor C1 is electrically connected to the discharge resistor R2 and discharged. In other words, when the first cover 32 is opened, the discharge switch 51 is activated by mechanical actuation, allowing the capacitor C1, which is subjected to a high voltage, to be discharged.Even if the capacitor C1 cannot be discharged via the discharge resistor R1 due to a failure of the switching element SW1, the activation of the discharge switch 51 by the mechanical actuation (opening of the first cover 32) allows the capacitor C1 to be discharged via the discharge resistor R2, thus ensuring the safety of the maintenance work. embodiment 3

[0055] The electronic device can include a locking mechanism that prevents the first cover 32 from closing when another cover, different from the first cover 32, is unlocked. An electronic device 2 according to embodiment 3 is described, with a focus on the differences from embodiment 1.

[0056] As in Fig. As shown in Figure 8, the housing 31 of the electronic device 2 has second openings 31b and 31c on the side opposite the side on which the first opening 31a is located. As shown in Fig. As shown in Figure 9, the electronic device 2 has a second cover 36, which can be opened and closed and covers the second opening 31b, and a second cover 37, which can be opened and closed and covers the second opening 31c. The electronic device 2 further has a locking mechanism 38 that locks the second cover 36, and a locking mechanism 39 that locks the second cover 37.

[0057] The second cover 36 rotates about a rotation axis AX3, which runs parallel to the Z-axis, and thereby opens or closes the second opening 31b. The second cover 36 consists of a plate-shaped material that can cover the entire second opening 31b and the surrounding area.

[0058] The second cover 37 rotates about a rotation axis AX4, which runs parallel to the Z-axis, and thereby opens or closes the second opening 31c. The second cover 37 consists of a plate-shaped material that can cover the entire second opening 31c and the surrounding area.

[0059] A key 40 of the locking mechanism 38 can only be removed when the second cover 36 is locked. A key 41 of the locking mechanism 39 can only be removed when the second cover 37 is locked.

[0060] As in Fig. 10 and Fig. As shown in Figure 11, the electronic device 2 has a key holder 61 that holds the key 40. The electronic device 2 also has a key holder 62 that holds the key 41, as shown in Figure 11. Fig. Figure 9 is shown. To simplify the drawings, the key is 41 in Fig. 10 and Fig. 11 not shown. The structure of the electronic device 2, apart from the key holders 61 and 62, corresponds to that of embodiment 1. To simplify the drawings, Fig. 10 and Fig. 11 only the discharge switch 21 among the components of the electronic device 2 which are included inside the housing 31; the rotation axis AX2 is not shown therein.

[0061] The key holder 61 has a retaining mechanism 61a which can be in an unlocked position in which the key 40 can be inserted and removed, as shown in Fig. 10 shown, or in a locked position in which the removal of the inserted key 40 is suppressed, as in Fig. The key holder 61 further comprises an opening-closing limiting mechanism 61b, which prevents the first cover 32 from closing when the retaining mechanism 61a is in the unlocked position, as shown in Figure 11. Fig. 10 shown, and the closing of the first cover 32 is made possible when the retaining mechanism 61a is in the locked position, as shown in Fig. 11 shown.

[0062] The insertion direction of the key 40 into the retaining mechanism 61a corresponds to the direction in which the first opening 31a extends, namely the Y-axis. The retaining mechanism 61a is shaped to rotate about an axis of rotation AX5, which extends in the insertion direction of the key 40. In other words, the retaining mechanism 61a is rotatable about the axis of rotation AX5 parallel to the Y-axis. The opening-closing limiting mechanism 61b consists of a projection attached to the retaining mechanism 61a, extending in a radial direction perpendicular to the axis of rotation AX5 of the retaining mechanism 61a. The projection rotates about the axis of rotation AX5 when the retaining mechanism 61a rotates.

[0063] The structure of the key holder 62 corresponds to that of the key holder 61. The key holder 62 has a retaining mechanism 62a, which is arranged either in the unlocked position, in which the key 41 can be inserted and removed, or in the locked position, in which removal of the inserted key 41 is prevented. The key holder 62 further has an opening-closing limiting mechanism 62b, which prevents the first cover 32 from closing when the retaining mechanism 62a is in the unlocked position, as shown in Fig. 10 shown, and the closing of the first cover 32 is made possible when the retaining mechanism 62a is in the locked position, as shown in Fig. 11 shown.

[0064] The insertion direction of the key 41 into the retaining mechanism 62a corresponds to the direction in which the first opening 31a extends, namely the Y-axis. The retaining mechanism 62a is shaped to rotate about an axis of rotation AX6, which extends in the insertion direction of the key 41. In other words, the retaining mechanism 62a is rotatable about the axis of rotation AX6 parallel to the Y-axis. The opening-closing limiting mechanism 62b consists of a projection attached to the retaining mechanism 62a, extending in a radial direction perpendicular to the axis of rotation AX6 of the retaining mechanism 62a. The projection rotates about the axis of rotation AX6 when the retaining mechanism 62a rotates.

[0065] As in Fig. Figure 10 shows that when an attempt is made to close the first cover 32 while the retaining mechanisms 61a and 62a are in the unlocked position, the contact section 35a of the displacement limiting element 35, which is attached to the first cover 32, comes into contact with the opening-closing limiting mechanisms 61b and 62b, which consist of projections. This prevents the first cover 32 from closing. When the retaining mechanisms 61a and 62a are in the unlocked position, the keys 40 and 41 can be removed from the retaining mechanisms 61a and 62a. This allows the second covers 36 and 37 to be locked. In other words, when the second covers 36 and 37 can be unlocked, the closing of the first cover 32 is prevented.

[0066] As in Fig. As shown in Figure 11, when the holding mechanisms 61a and 62a are in the locked position, the contact section 35a of the displacement limiting element 35, which is attached to the first cover 32, does not come into contact with the opening-closing limiting mechanisms 61b and 62b. This allows the first cover 32 to be closed. The key 40, which can only be removed from the locking mechanism 38 when the second cover 36 is locked, is inserted into the holding mechanism 61a. When the holding mechanism 61a, into which the key 40 is inserted, rotates from the unlocked position to the locked position, removal of the key 40 is suppressed, thus preventing the second cover 36 from being unlocked. Similarly, the key 41, which can only be removed from the locking mechanism 39 when the second cover 37 is locked, is inserted into the holding mechanism 62a.When the retaining mechanism 62a, into which the key 41 is inserted, rotates from the unlocked position to the locked position, removal of the key 41 is suppressed, thus preventing the unlocking of the second cover 37. Therefore, when the second covers 36 and 37 are locked, the keys 40 and 41 are inserted into the corresponding retaining mechanisms 61a and 62a, and the retaining mechanisms 61a and 62a are in the locked position, the first cover 32 can be closed.

[0067] As described above, the electronic device 1 according to embodiment 3 has a locking mechanism that prevents the first cover 32 from closing when the second covers 36 and 37 are unlockable. This can promote the secure locking of the second covers 36 and 37, and the electronic device 2 can thereby exhibit a high level of security.

[0068] The present disclosure is not limited to the embodiments described above. The electronic devices 1 and 2 are not limited to DC-to-three-phase converters, but can be any devices comprising the discharge resistor R2 and the discharge switch 21 or the discharge switch 51. For example, the electronic devices 1 and 2 can be a power conversion device installed in a rail vehicle of an AC power supply system, converting the AC power supplied by the power source into three-phase AC power. In this case, the electronic devices 1 and 2 can, in addition to those described in the Fig. The components shown in Figure 1 include a converter that converts alternating current to direct current, and the capacitor C1 can be discharged with the direct current output by the converter.

[0069] As another example, the electronic devices 1 and 2 can be a DC-DC converter that can be installed in a rail vehicle of the DC power supply system and converts the direct current supplied by a power source into direct current for the load device 91 and outputs the converted alternating current power.

[0070] As a further example, the electronic devices 1 and 2 can comprise several power conversion circuits 11 and capacitors C1, each associated with a specific power conversion circuit 11. The electronic devices 1 and 2 can include a common discharge circuit 12 shared by the multiple power conversion circuits 11, or separate discharge circuits 12 for each power conversion circuit 11. If the discharge circuit 12 is provided for each of the multiple power conversion circuits 11, each discharge switch 21 or each discharge switch 51 can be located near the first opening 31a.Thus, when the first cover 32 is closed, the movable element 23 of each discharge switch 21 or the movable element 53 of each discharge switch 51 can be arranged in the conductive position, and when the first cover 32 is open, the movable element 23 of each discharge switch 21 or the movable element 53 of each discharge switch 51 can be held in the non-conductive position.

[0071] The discharge circuit 12 can comprise only the discharge switch 21 and the discharge resistor R2, without the switching element SW1 and the discharge resistor R1. Likewise, the discharge circuit 12 can comprise only the discharge switch 51 and the discharge resistor R2.

[0072] The structures of the electronic devices 1 and 2 are not limited to the examples above. Any configuration can be adopted that makes it possible to position the movable element 23 of each discharge switch 21 or the movable element 53 of each discharge switch 51 in the non-conductive position when the first cover 32 is closed, and to keep the movable element 23 of each discharge switch 21 or the movable element 53 of each discharge switch 51 in the conductive position when the first cover 32 is open.

[0073] For example, the first cover 32 can rotate about an axis of rotation parallel to the X-axis to open and close the first opening 31a. The first cover 32 can be positioned vertically above the first cover 32 and rotate about the axis of rotation parallel to the X-axis, or it can be positioned vertically below the first cover 32 and rotate about the axis of rotation parallel to the X-axis.

[0074] The structure, mounting position, electrical connection position, mounting direction and the like of the discharge switch 21 or the discharge switch 51 are not limited to the examples mentioned above, but may have any configuration that makes it possible to switch off the discharge switch when the first cover 32 is closed and to switch it on when the first cover 32 is open.

[0075] For example, the discharge switches 21 and 51 do not necessarily have to include the preload elements 24 and 54. A modified example of the electronic device 1, which includes the discharge switch 21 without preload element 24, is shown in Fig. 12 and Fig. 13 shown. If the first cover 32 is in an open state, as shown in Fig. As shown in Figure 12, when the first cover 32 is moved into a closed state, the contact section 35a of the displacement limiting element 35 comes into contact with the movable element 23 before the first cover 32 is fully closed. As the first cover 32 continues to move towards the housing 31, the contact section 35a of the displacement limiting element 35 lifts one end of the movable element 23 vertically upwards while remaining in contact with the movable element 23. This causes the movable element 23 to rotate about the axis of rotation AX2. Specifically, the movable element 23 rotates clockwise when viewed in the direction of the negative Y-axis. When the first cover 32, as shown in Figure 12, is moved into a closed state, the contact section 35a of the displacement limiting element 35 comes into contact with the movable element 23. Fig. As shown in Figure 13, when fully closed, one end of the movable element 23 is spaced away from the terminal 22a. As a result, the discharge switch 21 is switched off.

[0076] If the first cover 32 is removed from the state in Fig. When the opening 13 is activated and the contact section 35a of the displacement limiting element 35 moves away from the movable element 23, one end of the movable element 23 moves vertically downwards due to its own weight. This causes the movable element 23 to rotate about the rotation axis AX2. Specifically, the movable element 23 rotates counterclockwise when viewed in the direction of the negative Y-axis. Then the movable element 23 comes to, as in Fig. Figure 12 shows both terminals 22a and 22b in contact. As a result, the discharge switch 21 is turned on.

[0077] As another example, one of the terminals 22a and 22b of the discharge switch 21 can be electrically connected to a connection point between the input terminal 1b and the power conversion circuit 11, and the other of the terminals 22a and 22b can be electrically connected to the discharge resistor R2.

[0078] As a further example, the discharge switches 21 and 51 are preferably switches that are switched on and off by mechanical actuation as described above, but can also consist of electronic switches, in particular optical switches, microswitches or the like, which are switched on when the first cover 32 is open and switched off when the first cover 32 is closed.

[0079] The preload elements 24 and 54 are not limited to coil springs but can be made of any elastic material, such as leaf springs, disc springs, or rubber. As described in the embodiments above, the preload elements 24 and 54 can exert a preload in the conductive position or a preload in the non-conductive position. If the preload elements 24 and 54 exert a preload in the non-conductive position, the displacement limiting element 35 attached to the first cover 32 can, for example, engage with the movable elements 23 and 53 when the first cover 32 is opened and push the movable elements 23 and 53 into the conductive position.

[0080] The structure of the displacement limiting element 35 is not limited to the examples mentioned above and can have any structure that allows the displacement limiting element 35 to come into contact with the movable element 23 or the movable element 53 when the first cover 32 is closed, thereby holding the movable element 23 or the movable element 53 in the non-conductive position. For example, the displacement limiting element 35 can have an end connected to the first cover 32 and a columnar shape extending in the Y-axis direction.

[0081] The embodiments described above can be combined as required. For example, the electronic device 2 can include a discharge switch 51 as shown in embodiment 2. As another example, the electronic device 2 can include the discharge switch 21 and the [unclear text]. Fig. 12 and Fig. The 13 depicted displacement limiting element comprises 35.

[0082] The structure of the locking mechanism present in the electronic device 2 is not limited to the examples mentioned above. For example, the electronic device 2 can suppress the closing of the first cover 32 when the holding mechanisms 61a and 62a are in the unlocked position by using an element separate from the displacement limiting element 35. A modified example of the electronic device 2, which has a projection element 42 separate from the displacement limiting element 35, is shown in Fig. 14 shown.

[0083] The projection element 42 is attached to one side of the first cover 32, facing the interior of the housing 31, and has a shape that extends away from the first cover 32 in one direction. When an attempt is made to close the first cover 32 while the retaining mechanisms 61a and 62a are in the unlocked position, the projection element 42 attached to the first cover 32 comes into contact with the opening-closing limiting mechanisms 61b and 62b, which consist of projections. This prevents the first cover 32 from closing. When the retaining mechanisms 61a and 62a are in the locked position, the projection element 42 attached to the first cover 32 does not come into contact with the opening-closing limiting mechanisms 62b and 62b, which consist of projections. This allows the first cover 32 to close.It is sufficient that the displacement limiting element 35 has a shape that comes into contact with the movable element 23 and not with the opening-closing limiting mechanisms 61b and 62b.

[0084] The orientation in which the electronic devices 1 and 2 are mounted in the rail vehicle is not limited to the examples mentioned above. The electronic devices 1 and 2 can be installed in any moving body, such as an automobile, an aircraft, or a ship, and not only in a rail vehicle, or at any stationary location.

[0085] The load device 91 is not limited to a three-phase induction motor, but can be a synchronous motor or a DC motor. The load device 91 is not limited to a motor, but can be any device installed in the rail vehicle.

[0086] The foregoing describes some exemplary embodiments for explanatory purposes. Although the above discussion has presented specific embodiments, those skilled in the art will recognize that changes in form and detail can be made without departing from the broader spirit and scope of the invention. Accordingly, the description and the drawings are to be regarded in an illustrative, not a limiting, sense. This detailed description is therefore not to be understood in a limiting sense, and the scope of the invention is determined only by the attached claims and the full range of equivalents to which such claims refer. Reference symbol list 1, 2 Electronic equipment 1a, 1b Input terminal 11 Power conversion circuit 12 Discharge circuit 21, 51 discharge switch 22a, 22b, 52a, 52b connection 23, 53 Movable element 24, 54 Preload element 25, 55 Connection holding element 26 Insulation element 31 cases 31a First opening 31b, 31c Second opening 32 First Cover 33 Mounting frames 34 Support element 35 Displacement limiting element 35a Contact section 36, 37 Second cover 38, 39 Locking mechanism 40, 41 keys 42 Protrusion element 55a, 55b, 56a, 56b Fastening section 56 holders for movable element 57 Extension and retraction mechanism 61, 62 Key holder 61a, 62a Holding mechanism 61b, 62b Opening-closing limiting mechanism 81 Cooling unit 91 Load device AX1, AX2, AX3, AX4, AX5, AX6 rotation axis C1 Capacitor R1, R2 discharge resistor SW1 switching element

Claims

[1] Electronic device comprising: a housing having a first opening and configured to receive an electronic component and a discharge resistor for discharging the electronic component; a discharge switch accommodated in the housing, the discharge switch comprising: a pair of terminals, one of the pair of terminals being electrically connected to the electronic component and the other of the pair of terminals being electrically connected to the discharge resistor, and a movable member made of a conductor and arranged in a conductive position in which the movable member is in contact with both of the pair of terminals, or in a non-conductive position in which the movable member is spaced from at least one of the pair of terminals; a first cover which is openable and closable and is designed to cover the first opening; and a displacement limiting member that allows the movable member to be arranged in the conductive position when the first cover is opened and holds the movable member in the non-conductive position when the first cover is closed, wherein when the movable element of the discharge switch is arranged in the conductive position, the electronic component is electrically connected to the discharge resistor, and when the movable element of the discharge switch is arranged in the non-conductive position, the electronic component is electrically separated from the discharge resistor. [2] The electronic device according to claim 1, wherein the displacement limiting member is fixed to a side of the first cover facing an interior of the housing, and has a contact portion having a plate-like shape extending in a direction away from the first cover, and the contact of the displacement limiting member with the movable member, when the first cover is closed, holds the movable member in the non-conductive position. [3] The electronic device according to claim 1 or 2, wherein the movable member has one end fixed to one of the two terminals and has a shape rotatable about the fixed end. [4] The electronic device according to claim 1 or 2, wherein the movable member has a shape that, in the conductive position, allows both of the pair of terminals to be fitted into the movable member, and the movable member is spaced from both of the pair of terminals in the non-conductive position. [5] The electronic device according to any one of claims 1 to 4, wherein the discharge switch further comprises a biasing member that biases the movable member into the conductive position. [6] Electronic device according to claim 5, wherein the prestressing element has an elastic body which deforms under external force and returns to its original shape when the external force is removed, and the movable element is arranged in the conducting position when the elastic body has its original shape. [7] Electronic device according to one of claims 1 to 6, wherein the housing further comprises one or more second openings, and the electronic device further comprising: one or more second covers which are openable and closable and are designed to cover the one or more second openings, one or more locking mechanisms that lock the one or more second covers and enable a key to be removed only when the one or more second covers are locked, and a key holder located within the housing and designed to hold the key. [8] Electronic device according to claim 7, wherein the key holder comprises: a holding mechanism arranged either in an unlocked position allowing insertion and removal of the key or in a locked position preventing removal of the inserted key, and an opening-closing limiting mechanism that suppresses the closing of the first cover when the holding mechanism is in the unlocked position and allows the closing of the first cover when the holding mechanism is in the locked position. [9] Electronic device according to claim 8, wherein an insertion direction of the key into the holding mechanism corresponds to a direction in which the first opening extends, the holding mechanism has a shape that is rotatable about a rotation axis that extends in the insertion direction of the key, and the opening-closing limiting mechanism is made of a projection fixed to the holding mechanism and extending in a radial direction perpendicular to the rotation axis of the holding mechanism, the projection rotating with the rotation of the holding mechanism. [10] The electronic device according to claim 9, wherein, when the holding mechanism is arranged in the unlocked position, the displacement restricting member attached to the first cover comes into contact with the projection, thereby suppressing the closing of the first cover. [11] The electronic device of claim 9, further comprising: a projection member fixed to a side of the first cover facing an interior of the housing and extending in a direction away from the first cover, wherein, when the holding mechanism is arranged in the unlocked position, the projection comes into contact with the projection member and thereby suppresses the closing of the first cover.

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