Voltage conversion device

Abstract

To provide a voltage conversion device that inspects and detects a connection state between terminals, and improves safety and reliability.SOLUTION: A voltage conversion device includes: an output terminal connected to a voltage conversion circuit; and an external connection terminal that connects the voltage conversion circuit with an electric circuit outside of the voltage conversion circuit via the output terminal. The voltage conversion device comprises: a voltage detection terminal which is provided annularly around the output terminal and at least part of which is contacted to the external connection terminal; and an abnormality determination unit that determines a connection state between the output terminal and the external connection terminal in the voltage conversion circuit. The voltage detection terminal detects a first voltage as a voltage of the output terminal, and a second voltage as a voltage of the external connection terminal. The abnormality determination part determines a contact state between the output terminal and the external connection terminal on the basis of a resistance value that is calculated on the basis of the first and second voltages detected.SELECTED DRAWING: Figure 3

Description

Technical Field

[0001] The present invention relates to a voltage conversion device.

Background Art

[0002] In a voltage conversion device, when liquid, foreign matter, etc. adhere, corrosion occurs. For example, when the contact resistance at the connection part between terminals increases, there are many problems leading to poor connection. In such a state, it will cause a decrease in the output voltage and an increase in the heat generation at the contact part. For example, the resin part which is a component of the output terminal is carbonized, and due to the decrease in the insulation between the output terminal and the case, an overcurrent continuously flows, which may lead to a vehicle fire.

[0003] As such a countermeasure, for example, in Patent Document 1 below, a structure for obtaining heat insulation so that heat transfer from external vehicle-side terminals, wire harnesses, etc. does not reach the internal circuit is disclosed.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] In a voltage conversion device, a large current passes through the DCDC output terminal, but since the output voltage is relatively low, a simple structure has been conventionally adopted. However, in a simple structure, the protection against the external environment is also simplified, so depending on the mounting position, foreign matter etc. easily adheres, and the fastening part corrodes or the contact resistance increases. As a result, even with the conventional heat insulation countermeasures, there is a possibility of overheating and burning during energization. Also, since the output terminal does not have a detection terminal, there has been a problem that the contact state between the output terminal and the vehicle-side connection terminal cannot be continuously detected and the contact failure location cannot be specified.

Means for Solving the Problems

[0006] A voltage conversion device comprising an output terminal connected to a voltage conversion circuit and an external connection terminal that connects the voltage conversion circuit and an external electric circuit outside the voltage conversion circuit via the output terminal, the voltage conversion device comprising: a voltage detection terminal that is provided in an annular shape around the output terminal and at least a part of which contacts the external connection terminal; and an abnormality determination unit that determines a connection state between the output terminal and the external connection terminal in the voltage conversion circuit, wherein the voltage detection terminal detects a first voltage that is the voltage of the output terminal and a second voltage that is the voltage of the external connection terminal, and the abnormality determination unit determines a contact state between the output terminal and the external connection terminal based on a resistance value calculated based on the detected first voltage and the second voltage.

Advantages of the Invention

[0007] According to the present invention, it is possible to provide a voltage conversion device that detects and detects a connection state between terminals, and improves safety and reliability.

Brief Description of the Drawings

[0008]

Figure 1

Figure 2

Figure 3

Figure 4

Figure 5

Figure 6

Figure 7

Embodiments for Carrying Out the Invention

[0009] Hereinafter, embodiments of the present invention will be described with reference to the drawings. The following description and drawings are examples for explaining the present invention, and for the sake of clarity of explanation, appropriate omissions and simplifications have been made. The present invention can be implemented in various other forms. Unless otherwise particularly limited, each component may be in a single or plural number.

[0010] The positions, sizes, shapes, ranges, etc. of the respective components shown in the drawings may not represent the actual positions, sizes, shapes, ranges, etc. in order to facilitate understanding of the invention. For this reason, the present invention is not necessarily limited to the positions, sizes, shapes, ranges, etc. disclosed in the drawings.

[0011] (One Embodiment and Overall Configuration) (Figs. 1 and 2) The DCDC output terminal 100 is an output terminal of a DC low voltage connected to a voltage conversion circuit in the DCDC converter 400. It is integrally molded with the terminal holder 110 and is fixed to the housing of the DCDC converter 400 by screwing. A vehicle-side connection terminal 300 is fastened and fixed to the DCDC output terminal 100 using a nut 500. By doing so, the DCDC converter 400 is connected to an external electric circuit of the DCDC converter 400 via the vehicle-side connection terminal 300.

[0012] (Fig. 3) The terminal holder 110 is, for example, a resin material, and has a function of holding and fixing the DCDC output terminal 100 with respect to the DCDC converter 400, and ensures electrical insulation at the DCDC output terminal 100.

[0013] The DCDC output terminal 100 includes a screw portion 101 for holding and fixing the vehicle-side connection terminal 300. The DCDC output terminal 100 electrically connects the DCDC output terminal 100 and the vehicle-side connection terminal 300 by fastening and fixing the vehicle-side connection terminal 300 using a nut 500.

[0014] When the DCDC output terminal 100 and the vehicle-side connection terminal 300 are connected and in contact with each other, a voltage detection terminal 200 for detecting the voltage of the DCDC output terminal 100 and the voltage of the vehicle-side connection terminal 300 is provided around the DCDC output terminal 100. The voltage detection terminal 200 has an internal lead wire 201, and is connected to a voltage sensing circuit (not shown) in the voltage conversion circuit inside the DCDC converter 400 via the internal lead wire 201.

[0015] The voltage detection terminal 200 is integrated with the DCDC output terminal 100 by a terminal holding member 110 that holds and fixes the DCDC output terminal 100. Since the voltage detection terminal 200 is made of metal, it has a heat conduction effect, and can transfer the heat of the vehicle-side connection terminal 300 to the temperature detection element of the DCDC converter 400.

[0016] The vehicle-side connection terminal 300 has a first contact portion 310 that is the portion in contact with the DCDC output terminal 100. The vehicle-side connection terminal 300 also has a second contact portion 210 that is the portion where at least a part is in contact with the voltage detection terminal 200.

[0017] The main power output from the DCDC output terminal 100 is supplied to the vehicle-side connection terminal 300 via the first contact portion 310 and is energized with the vehicle-side battery. There is a contact resistance at this contact portion 310, and a voltage drop occurs due to the current flowing from the DCDC output terminal 100 to the vehicle-side connection terminal 300. Generally, the voltage of the vehicle-side connection terminal 300 is lower than the voltage of the DCDC output terminal 100. Since this voltage drop amount is determined by the contact resistance state if the current amount is the same, when the contact portion is corroded, etc., the contact resistance increases significantly, so the voltage drop amount becomes large.

[0018] In order to measure the contact resistance of the first contact portion 310 related to the voltage drop in this way, a control device is provided that monitors a voltage sensing circuit (not shown) within the DCDC converter 400. This control device calculates the voltage difference by comparing, for example, the voltage (first voltage) of the DCDC output terminal 100 detected by the voltage detection terminal 200 and the voltage (second voltage) of the vehicle-side connection terminal 300, and calculates the contact resistance value of the first contact portion 310 by dividing the voltage difference by the DCDC output current value.

[0019] Further, the control device has an abnormality determination unit (not shown) for determining the connection state of the first contact portion 310 based on the calculated resistance value. Thereby, before the first contact portion 310 enters a dangerous connection state such as corrosion, the deterioration of the connection state can be detected by the abnormality determination unit, and for example, by outputting warning information regarding the connection state, the inspection of the DCDC converter 400 can be prompted. Also, by this means, it is possible to reduce the current passing through the voltage detection terminal 200 and make it less susceptible to fluctuations in the contact resistance value.

[0020] Also, by detecting the contact resistance, which is one of the causes of heat generation, even without preventing heat transfer, control such as suppressing the output current that conducts the DCDC output terminal 100 according to the magnitude of the contact resistance value or stopping the operation of the electrical circuit of the DCDC converter 400 can be added, thereby suppressing the heat generation of the DCDC converter 400 itself.

[0021] Note that since a large current passes through the contact portion 310 due to the connection between the DCDC output terminal 100 and the vehicle-side connection terminal 300, the contact area may be made as wide as possible in order to lower the contact resistance.

[0022] (FIG. 4, FIG. 5) The voltage detection terminal 200 is provided in an annular shape so as to contact the vehicle-side connection terminal 300 partially or entirely around the output terminal 100. Further, since the voltage detection terminal 200 is electrically connected not only to the voltage sensing circuit provided inside the DCDC converter 400 but also to the temperature detection element by the voltage detection unit lead-out terminal 251, it is possible to grasp an abnormal temperature rise or the like of the vehicle-side connection terminal 300. By doing so, when a temperature exceeding a predetermined reference is detected, for example, by transitioning the state in the fail-safe direction, it is possible to prevent the vehicle-side connection terminal 300 from melting. Further, by performing the connection state between the terminals using both voltage detection and temperature detection, the connection reliability between the terminals can be further improved.

[0023] Note that the voltage detection terminal 200 may have a protruding shape protruding toward the vehicle-side connection terminal 300 in order to improve the contact with the vehicle-side connection terminal 300 and facilitate the detection of the voltage of the vehicle-side connection terminal 300. Further, the voltage detection terminal 200 may have spring properties, and by doing so, a buffer is added to the contact state between the vehicle-side connection terminal 300 and the voltage detection terminal 200, improving the connection reliability.

[0024] (Modification example) (Figs. 6 and 7) The voltage detection terminal 250 may be provided in a plurality of divided annular shapes around the DCDC output terminal 100. The voltage detection terminal 200 divided in this way is independently connected to the sensing circuit and the temperature detection element in the DCDC converter 400 housing via the internal lead-in wire and the lead-out terminal 251 connected to each of them. In this way, the voltage detection terminal 200 divided into a plurality of annular shapes can partially grasp the change in the connection state by increasing the connection points with the vehicle-side connection terminal 300 and perform divided detection, and even if there is a deterioration in the connection state due to partial corrosion or the like, it can be detected, and the detection accuracy of the deterioration in the connection state can be improved.

[0025] According to the embodiment of the present invention described above, the following operational effects are achieved.

[0026] (1) A voltage conversion device 400 includes an output terminal 100 connected to a voltage conversion circuit and an external connection terminal 300 that connects the voltage conversion circuit and an external electric circuit outside the voltage conversion circuit via the output terminal. The voltage conversion device 400 further includes a voltage detection terminal 200 that is provided annularly around the output terminal 100 and at least partially contacts the external connection terminal 300, and an abnormality determination unit that determines a connection state between the output terminal 100 and the external connection terminal 300 in the voltage conversion circuit. The voltage detection terminal 200 detects a first voltage that is the voltage of the output terminal 100 and a second voltage that is the voltage of the external connection terminal 300. The abnormality determination unit determines a contact state between the output terminal 100 and the external connection terminal 300 based on a resistance value calculated based on the detected first voltage and second voltage. By doing so, it is possible to provide a voltage conversion device that detects and detects the connection state between terminals, and improves safety and reliability.

[0027] (2) The voltage detection terminal 200 is provided in a plurality of divided annular shapes. By doing so, the detection accuracy can be improved.

[0028] (3) The voltage detection terminal 200 has spring properties. By doing so, the connection reliability between the vehicle-side connection terminal and the detection terminal can be improved.

[0029] (4) The voltage detection terminal 200 has a protrusion shape. By doing so, the connection reliability between the vehicle-side connection terminal and the detection terminal can be improved.

[0030] Note that the present invention is not limited to the above-described embodiments, and various modifications and other configurations can be combined without departing from the gist thereof. Further, the present invention is not limited to those having all the configurations described in the above embodiments, and also includes those in which a part of the configuration is deleted.

Explanation of Reference Numerals

[0031] 100 DCDC output terminal 101 Threaded portion 110 Terminal holding member 200 Voltage detection terminal 201 Internal lead-in wire 210 Second contact part 250 Voltage detection part 251 Voltage detection part lead-out terminal 300 Vehicle-side connection terminal 310 First contact part 400 DCDC converter 500 Nut

Claims

1. An output terminal connected to a voltage conversion circuit, and an external connection terminal that connects the voltage conversion circuit and an external electric circuit outside the voltage conversion circuit via the output terminal, the voltage conversion device comprising: a voltage detection terminal provided annularly around the output terminal and at least partially contacting the external connection terminal; and an abnormality determination unit that determines a connection state between the output terminal and the external connection terminal in the voltage conversion circuit, wherein the voltage detection terminal detects a first voltage that is the voltage of the output terminal and a second voltage that is the voltage of the external connection terminal, and the abnormality determination unit determines a contact state between the output terminal and the external connection terminal based on a resistance value calculated based on the detected first voltage and second voltage voltage conversion device.

2. The voltage detection terminal is provided in a plurality of divided annular shapes The voltage conversion device according to claim 1.

3. The voltage detection terminal has spring properties The voltage conversion device according to claim 1.

4. The voltage detection terminal has a protrusion shape The voltage conversion device according to claim 1.

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