JP2011232236A - Power supply device - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a power supply device capable of executing insulation pressure test in a state of a finished product.SOLUTION: In the power supply device 1 equipped with surge absorbers 4, 5 between inputs 2a, 2b and a frame grand 8 in a chassis frame 20 storing an electronic circuit substrate 10, a short bar 6 is connected to the surge absorbers 4, 5, and an opening 21A and a projecting piece 21 facing the opening 21A are provided on the chassis frame 20. The short bar 6 and the projecting piece 21 are coupled so as to enable conducting by a fixing screw 7 screwed in from the outside through the opening 21A of the chassis frame 20, while sandwiching an insulating member 10 therebetween.

Description

  The present invention relates to a power supply device having a mechanism for protecting a power supply circuit from an overvoltage such as lightning surge application.

  Conventionally, in order to protect a circuit from a momentary overvoltage (surge voltage) such as lightning surge application, a power supply device having a surge absorber such as a varistor between a power supply input and ground is known. This type of surge absorber is soldered on, for example, a printed circuit board pattern, but it is necessary to separate the surge absorber on the circuit in the dielectric strength test of the apparatus. For this reason, it is known that a connector that can be easily inserted and removed from an electronic circuit board is provided so that the connection of the surge absorber can be easily interrupted in the dielectric strength test (see, for example, Patent Document 1).

JP-A-10-253695

However, since the electronic circuit board on which the surge absorber is mounted is housed inside the chassis frame in the state of the finished product of the power supply, at least the chassis is required to separate the surge absorber on the circuit when performing a dielectric strength test. It was necessary to remove a part of the frame, such as a lid or a cover. Therefore, there is a problem that the withstand voltage test cannot be performed in the state of the completed device, and the number of steps for performing the withstand voltage test increases.
An object of the present invention is to solve the above-described problems of the conventional technology and to provide a power supply device capable of performing a dielectric strength test in a finished product state.

In order to achieve the above object, the present invention provides a power supply apparatus including a surge absorber between an input and a frame ground in a chassis frame that houses an electronic circuit board, wherein a short bar is connected to the surge absorber, The chassis frame is provided with an opening and a protruding piece facing the opening, and the short bar and the protruding piece can be connected to each other by a fixing screw that is screwed from the outside through the opening of the chassis frame with an insulating member interposed therebetween. It is connected to.
According to this configuration, since the fixing screw for electrically connecting the projecting piece provided on the short bar and the chassis frame can be detached from the outside of the chassis frame, the chassis is accommodated in the state in which the electronic circuit board is accommodated inside the chassis frame. The connection between the surge absorber and the frame ground can be intermittently disconnected without disassembling the frame, so that the surge absorber can be disconnected on the circuit, and the withstand voltage test can be performed with the power supply device in a finished product state.

  According to the present invention, the surge absorber housed inside the chassis frame can be separated on the circuit by a simple operation of removing the fixing screw from the outside of the chassis frame, so that the power supply device can be obtained without disassembling the chassis frame. The insulation withstand voltage test can be performed in the finished product state.

It is a circuit diagram of the power supply device of this embodiment. It is a perspective view which shows the exterior of a power supply device. It is a figure which shows the main body of a power supply device. It is a figure which shows the structure of the main body of a power supply device, and an electronic circuit board. It is a fragmentary sectional view which shows the connection structure of a short bar and a chassis frame.

Hereinafter, embodiments of the present invention will be described with reference to the drawings.
FIG. 1 is a circuit diagram of a power supply device 1 according to an embodiment to which the present invention is applied. The power supply device 1 has inputs 2a and 2b and outputs 3a and 3b, and includes a power supply circuit 31 therebetween. Between the inputs 2a and 2b and the power supply circuit 31, a protection circuit 30 for protecting the power supply circuit 31 from momentary overvoltage such as lightning surge application is provided. The outputs 3 a and 3 b of the power supply device 1 are connected to a load 32. The power supply device 1 is supplied with DC 48V power from the inputs 2a and 2b.

  The protection circuit 30 includes surge absorbers 4 and 5 such as varistors inserted between the power supply inputs 2 a and 2 b and the frame ground 8. When a surge voltage is applied to the power supply line, the surge absorbers 4 and 5 absorb the surge and protect the surge from entering the power supply circuit 30. A short bar 6 is provided at a connection point between the surge absorbers 4 and 5, and the short bar 6 is fixed to the electronic circuit board 10 with screws 12 and 13. The frame ground 8 is a later-described chassis frame 20 that forms an exterior of the power supply device 1, and the frame ground 8 and the short bar 6 are connected by an FG screw (fixing screw) 7.

As shown in FIG. 2, the chassis frame 20 of the power supply device 1 is formed in a substantially rectangular shape, and includes a lid 20A and a box-shaped main body 20B. In the state of the finished product of the power supply device 1, the lid 20 </ b> A that forms the three surfaces of the chassis frame 20 is screwed into the opening of the main body 20 </ b> B of the chassis frame 20 with a screw (not shown). The main body 20B that forms the remaining three surfaces of the chassis frame 20 is provided with a projecting piece 21 formed by cutting and raising a part of the bottom 20C of the main body 20B toward the inside of the chassis frame 20.
According to this configuration, when assembling the power supply device, the electronic circuit board can be easily fixed inside the chassis frame with the lid 20A removed from the box-shaped main body 20B of the chassis frame.
Further, outputs 3a and 3b are formed on one side surface of the main body 20B in the short side direction, and inputs 2a and 2b are formed on the other side surface although not shown. A handle 24 is provided on the side surface on which the inputs 2a and 2b are formed in order to facilitate carrying of the power supply device 1.

  As shown in FIGS. 3A and 3B, boss portions 22 provided at, for example, four corners of the bottom portion 20C are provided on the back surface of the bottom portion 20C of the main body 20B (the inner surface of the chassis frame 20). . Further, the protruding piece 21 is formed in a substantially L shape, and the height of the protruding piece 21 is the same as the height of the boss portion 22. A screw hole 23 is provided on a surface substantially parallel to the bottom 20 </ b> C of the projecting piece 21. Since the protruding piece 21 is formed by cutting and raising a part of the bottom portion 20C, an opening 21A is formed around the protruding piece 21 in the bottom portion 20C, and the protruding piece 21 faces the opening 21A. The size of the opening 21 </ b> A is small enough to allow a single screwdriver to enter the FG screw 7 from the opening 21 </ b> A and connect the projecting piece 21 and the short bar 6 through the screw hole 23. Can do.

  As shown in FIGS. 4B and 4C, the boss portion 22 is loaded with an electronic circuit board 10 on which a power supply circuit and a protection circuit are formed. The electronic circuit board 10 is fixed to the boss part 22 with the screw 11 and supported in a state of being lifted from the bottom part 20C. The electronic circuit board 10 extends substantially over the chassis frame 20. The surge absorbers 4 and 5 are connected to the electronic circuit board 10 by soldering or the like, and are connected to the short bar 6 by a pattern 14 formed on the electronic circuit board 10 as shown in FIG. . Further, the projecting piece 21 formed on the chassis frame 20 is addressed to the back surface 10 b of the electronic circuit board 10.

The short bar 6 is disposed at a position facing the protruding piece 21, and is fixed to the surface 10 a of the electronic circuit board 10 with screws 12 and 13 so as to be in close contact with the pattern 14. Further, the short bar 6 is formed with a hole into which the FG screw 7 is screwed at a position where it overlaps with the screw hole 23 provided in the protruding piece 21.
An insulating member 15 (see FIG. 5) is disposed between the projecting piece 21 and the short bar 6, and the projecting piece 21 and the short bar 6 are not conductive. When the projecting piece 21 and the short bar 6 are arranged with the electronic circuit board 10 sandwiched between them as shown in FIGS. 4B and 4C, the electronic circuit board 10 becomes an insulating member, There is no conduction between the piece 21 and the short bar 6.

  The FG screw 7 is provided to be screwed through the opening 21A. The FG screw 7 is screwed from the outside of the chassis frame 20 through the opening 21A, and the projecting piece 21 and the short bar 6 are connected by the FG screw 7 to connect the surge absorbers 4 and 5 and the frame ground 8 on the circuit. be able to. Further, in the state where the FG screw 7 is removed, the connection between the projecting piece 21 and the short bar 6 is cut off, and the surge absorbers 4 and 5 are not connected to the frame ground 8, and the surge absorbers 4 and 5 Disconnected on the circuit.

The protruding piece 21 and the boss portion 22 for fixing the electronic circuit board 10 are formed at the same height, and the protruding piece 21 is directed to the back surface 10 b of the electronic circuit board 10.
According to these configurations, the protruding piece 21 of the chassis frame 20 formed at the same height as the boss portion 22 is addressed to the back surface of the electronic circuit board 10 that is supported in a floating state on the bottom portion 20C of the main body 20B. Therefore, even if the FG screw 7 is fixed to the projecting piece 21, the electronic circuit board 10 can be prevented from bending even when the projecting piece 21 supports the electronic circuit board 10 from below. . Further, since the projecting piece 21 faces the opening 21A provided in the bottom 20C of the main body 20B of the chassis frame 20, the FG screw 7 can be easily screwed from the outside of the chassis frame 20 through the opening 21A. Since the FG screw 7 can be easily removed from the outside of the chassis frame 20 when the 21 and the short bar 6 are disconnected, the number of man-hours during the dielectric strength test can be reduced.

  By the way, in order to protect the power supply circuit 31 (see FIG. 1), it is necessary to connect the surge absorbers 4 and 5 having an operating voltage lower than the predetermined withstand voltage of the power supply device 1 to the electronic circuit board 10. In some cases, a voltage higher than the operating voltage of the surge absorbers 4 and 5 is applied to the electronic circuit board 10 to the surge absorbers 4 and 5 when the dielectric strength test of the power supply device 1 is performed. For this reason, insulation failure occurs when the surge absorbers 4 and 5 are connected. Therefore, it is necessary to separate the surge absorbers 4 and 5 on the power supply circuit and perform a dielectric strength test.

In the finished product state of the power supply device 1, the lid 20 </ b> A is screwed to the chassis frame 20, and the electronic circuit board 10 fixed to the bottom 20 </ b> C of the main body 20 </ b> B is accommodated inside the chassis frame 20. In this state, by removing the FG screw 7 from the projecting piece 21 with a screwdriver or the like through a small opening 21A provided in the bottom portion 20C, the connection between the surge absorbers 4, 5 and the frame ground 8 is broken, and the surge absorbers 4, 5 Can be easily separated on the power supply circuit. This makes it possible to carry out the dielectric strength test simply by removing the FG screw 7 from the outside of the chassis frame 20 with the power supply device 1 in a finished product state.
At the end of the dielectric strength test, the FG screw 7 is screwed again from the outside of the chassis frame 20 through the small opening 21A provided in the bottom portion 20C, and the FG screw 7 is screwed to the projecting piece 21 and the short bar 6 with a screwdriver or the like. Thus, the projecting piece 21 and the short bar 6 are connected, and the surge absorbers 4 and 5 can be easily connected to the frame ground 8.

  Since the opening 21A of the bottom portion 20C can be formed small, the appearance of the chassis frame 20 is not greatly impaired. Therefore, the bottom portion 20C may be arranged on either the top surface or the bottom surface of the chassis frame 20. However, when the bottom portion 20C is disposed on the bottom surface side of the power supply device 1, the appearance of the power supply device 1 is particularly affected. There is nothing.

As mentioned above, although this invention was demonstrated based on embodiment, this invention is not limited to this. In the present embodiment, the projecting piece 21 is formed by cutting and raising a part of the bottom portion 20C of the chassis frame 20 toward the inside of the chassis frame 20. However, the present invention is not limited to this. It is good also as a structure provided with the protrusion 21 by forming.
In the present embodiment, the projecting piece 21 and the short bar 6 are arranged with the electronic circuit board 10 interposed therebetween. However, the present invention is not limited to this, and as shown in FIG. A hole 10c through which the short bar 6 fixed to the surface 10a protrudes is provided in the electronic circuit board 10, and an insulating member 15 is sandwiched between the short bar 6 and the protruding piece 21, and the FG screw 7 is screwed. good.
Other detailed configurations can be arbitrarily changed.

1 Power supply 4 Surge absorber 6 Short bar 7 FG screw (fixing screw)
8 Frame ground 10 Electronic circuit board (insulating material)
DESCRIPTION OF SYMBOLS 15 Insulation member 20 Chassis frame 20A Cover body 20B Main body 20C Bottom part 21 Projection piece 21A Opening 22 Boss part

Claims (1)

  In a power supply apparatus having a surge absorber between an input and a frame ground inside a chassis frame containing an electronic circuit board, a short bar is connected to the surge absorber, an opening is formed in the chassis frame, and a projecting piece facing the opening And the short bar and the projecting piece are connected so as to be conductive with a fixing screw screwed from the outside through the opening of the chassis frame with an insulating member interposed therebetween.

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