Thermal safety mechanism, electronic control unit and vehicle

Abstract

The utility model provides a thermal safety mechanism, an electronic control unit and a vehicle, the thermal safety mechanism is used for temperature protection of a vehicle electronic control unit circuit, the thermal safety mechanism comprises a PCB, a conductive part, a first conductor and a second conductor, the first conductor and the second conductor are arranged on the PCB in a spaced mode, the conductive part is arranged close to the PCB, and the conductive part is arranged close to the PCB. The conductive part is arranged on the first conductor and the second conductor and is fixedly connected to the first conductor and the second conductor through a meltable connecting part so as to be electrically connected with the first conductor and the second conductor respectively, and when the PCB is arranged in parallel to the gravity direction of the conductive part and the connecting part is melted, the PCB can be electrically connected with the first conductor and the second conductor. The electric connection between the conductive part and at least one of the first conductor and the second conductor is disconnected through the gravity effect.

Description

Technical Field

[0001] The present application relates to the technical field of circuit safety of a vehicle electronic control unit, and in particular, to a thermal insurance mechanism, an electronic control unit and a vehicle. Background Art

[0002] Thermal fuses are often used in the circuits of vehicle electronic control units for temperature protection of electronic control units to prevent thermal accidents. Known thermal fuses are usually constructed in a structure similar to a shrapnel, one end of which is installed on a circuit board by welding, and a certain amount of elastic potential energy is stored during installation. The two ends of the thermal fuse are respectively connected to the circuit, and play a conductive role when the electronic control unit works at a normal temperature. When an abnormality occurs in the electronic control unit, resulting in an abnormal current, this will cause high temperature to be generated inside the electronic control unit. When the thermal fuse is heated to a certain temperature value by this high temperature, the solder at one end of the thermal fuse shrapnel will be melted and bounced open under the action of internal stress, thereby disconnecting the power supply, playing a protective role, and preventing thermal accidents. Since this thermal fuse needs to be precisely bent during installation to store elastic potential energy, the installation of this thermal fuse usually requires the assistance of a complex installation mechanism.

[0003] It should be noted that the information disclosed in the above background technology section is only used to enhance the understanding of the background of the present disclosure, and therefore may include information that does not constitute the prior art known to ordinary technicians in the field. Utility Model Content

[0004] According to different aspects, one of the purposes of the present application is to simplify the installation process of a thermal fuse.

[0005] In addition, the present application is also intended to solve or alleviate other technical problems existing in the prior art.

[0006] According to one aspect of the present application, there is provided:

[0007] A thermal insurance mechanism is used for temperature protection of a circuit of a vehicle electronic control unit, comprising a PCB, a conductive member, and a first conductor and a second conductor arranged on the PCB at a distance from each other, wherein the conductive member is arranged close to the PCB and fixedly connected to the first conductor and the second conductor through a fusible connecting portion to be electrically connected to the first conductor and the second conductor respectively, wherein when the PCB is arranged parallel to the gravity direction of the conductive member and the connecting portion is melted, the conductive member is disconnected from the electrical connection with at least one of the first conductor and the second conductor by the action of gravity.

[0008] According to another aspect of the present application, the present application provides an electronic control unit, wherein the electronic control unit includes a first conductor line, a second conductor line, the thermal insurance mechanism described above, and a shell, the first conductor line is connected to a power supply, the second conductor line is connected to an external power unit, the first conductor line and the second conductor line are electrically connected through the thermal insurance mechanism, the first conductor is part of the first conductor line, and the second conductor is part of the second conductor line.

[0009] According to yet another aspect of the present application, the present application provides a vehicle, wherein the vehicle includes the electronic control unit described above, and the PCB board is placed parallel to the vertical direction of the vehicle.

[0010] The benefits of this application include:

[0011] The thermal insurance mechanism of the present application does not need to bend the fuse (conductive member) when installing it to give it elastic potential energy. Instead, by changing the arrangement of the PCB board, the gravitational potential energy of the fuse is used to disconnect the fuse when the temperature is too high. While ensuring that the fuse can normally disconnect the circuit at high temperatures, the installation method of the fuse is greatly simplified. When installing the fuse, no additional installation steps are required after welding, which can save the operating space required for installation and reduce the surface mounting area of ​​the PCB board. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The above and other features of the present application will become apparent with reference to the accompanying drawings, in which:

[0013] Figure 1 A schematic structural diagram of a thermal insurance mechanism proposed in accordance with an embodiment of one aspect of the present application is shown;

[0014] Figure 2 A schematic structural diagram of a thermal insurance mechanism according to another embodiment of the present application is shown;

[0015] Figure 3 and Figure 4 Schematic diagrams showing two different welding areas of the conductive member and the first conductor and the second conductor respectively;

[0016] Figure 5 A circuit diagram of an electronic control unit according to an embodiment of another aspect of the present application is shown;

[0017] Figure 6 The positional relationship between the housing and storage portion of the electronic control unit and the thermal insurance mechanism is schematically shown. DETAILED DESCRIPTION

[0018] It is easy to understand that according to the technical solution of the present application, without changing the essential spirit of the present application, a person skilled in the art can propose a variety of interchangeable structural modes and implementation modes. Therefore, the following specific implementation modes and drawings are only exemplary descriptions of the technical solution of the present application, and should not be regarded as the entirety of the present application or as a limitation or restriction on the technical solution of the present application.

[0019] The directional terms such as up, down, left, right, front, back, front, back, top, bottom, etc. mentioned or may be mentioned in this specification are defined relative to the structures shown in the drawings. They are relative concepts and may change accordingly according to their different positions and different usage states. Therefore, these or other directional terms should not be interpreted as restrictive terms. In addition, the terms "first", "second", "third", etc. or similar expressions are only used for description and distinction purposes, and cannot be understood as indicating or implying the relative importance of the corresponding components or the order or assembly order of the components.

[0020] refer to Figure 1 , which shows a schematic diagram of the structure of a thermal insurance mechanism 100 proposed according to an embodiment of one aspect of the present application. The thermal insurance mechanism 100 of the present application is used for temperature protection of the circuit of an electronic control unit, especially a vehicle electronic control unit. By changing the arrangement of the PCB board 110 and the conductive member 120, the conductive member 120 can use its own gravity to disconnect the electrical connection in the circuit when the circuit temperature is too high, thereby simplifying the installation method of the conductive member 120 and the PCB board 110. The thermal insurance mechanism 100 includes a PCB board 110, a conductive member 120, and a first conductor 130 and a second conductor 140 arranged on the PCB board 110 at intervals from each other. The conductive member 120 is arranged close to the PCB board 110 and is fixedly connected to the first conductor 130 and the second conductor 140 through fusible connecting parts 150 and 160, so that the conductive member 120 is electrically connected to the first conductor 130 and the second conductor 140 respectively, so that a passage is formed between the first conductor 130 and the second conductor 140. The PCB board 110 is arranged in the circuit parallel to the gravity direction of the conductive member (for example, along the vertical direction of the vehicle when arranged in the vehicle). In this way, when the circuit temperature is normal, the conductive member 120 is fixedly connected to the PCB board 110 due to the above-mentioned connecting parts 150 and 160, and connects the first conductor 130 and the second conductor 140, and the circuit works normally; when the circuit temperature is too high, especially when the circuit temperature reaches the temperature that makes the connecting parts 150 and 160 melt, the connecting part of the conductive member 120 and the first conductor 130 and the second conductor 140 is melted, and it slides along the PCB board 110 due to its own gravity, thereby disconnecting the electrical connection with at least one of the first conductor 130 and the second conductor 140, especially disconnecting the connection with both the first conductor 130 and the second conductor 140.

[0021] In one embodiment of one aspect of the present application, the conductive member 120 is respectively soldered to the first conductor 130 and the second conductor 140 by soldering, that is, the fusible connecting parts 150 and 160 of the conductive member 120 are formed by tin or a tin alloy. Tin is a metal with a low melting point. In this embodiment, the temperature at which the connecting part melts is between 210°C and 240°C. Therefore, when the temperature of the circuit exceeds the melting temperature, the connecting part will melt, and the fixed connection between the conductive member 120 and the first conductor 130 and the second conductor 140 will be disconnected, and the conductive member 120 will fall off along the PCB board 110 due to its gravity. At the same time, the tin melted into liquid can form a lubricant between the PCB board 110 and the conductive member 120, so that the friction coefficient between the conductive member 120 and the PCB board 110 is less than 1, which is more conducive to the conductive member 120 sliding along the PCB board 110.

[0022] In one embodiment of the present invention, the conductive member 120 is made of copper. For example, it is configured in the shape of a cuboid and is attached to the PCB board 110 in a direction parallel to the PCB board 110. Figure 1 In the embodiment, the length direction of the conductive member 120 is parallel to the gravity direction. This not only allows the conductive member 120 to have a sufficient length to cross the gap between the first conductor 130 and the second conductor 140 and connect to the first conductor 130 and the second conductor 140, but also helps the conductive member 120 to have a large enough area for welding. When the connecting parts 150 and 160 melt, it is easier to slide down along the surface of the PCB board 110 instead of falling directly from the PCB board 110, so that the position where the conductive member 120 slides off the PCB board 110 is easier to determine. It should be understood that in Figure 1 In the embodiment, the first conductor 130 and the second conductor 140 schematically extend in the vertical direction of the vehicle, while in the embodiment not shown, the first conductor 130 and the second conductor 140 can, for example, extend in the longitudinal direction or the lateral direction of the vehicle. In this case, it can be configured, for example, that the length direction of the conductive member 120 is arranged perpendicular to the vertical direction of the vehicle, so that the conductive member 120 can have a longer length in the vertical direction perpendicular to the vehicle, which facilitates its connection with the first conductor 130 and the second conductor 140.

[0023] In one embodiment of one aspect of the present application, the conductive member 120 is configured to be suitable for any slope for normal vehicle driving, for example, it is applicable when the slope is from -35° to +35°. When the vehicle is driving on a negative slope, the conductive member 120 is still subject to the full force of its gravity, so the sliding of the conductive member from the PCB board 110 is not affected. When the vehicle is driving on a positive slope, the force of the conductive member 120 sliding down the PCB board 110 is the component of gravity along the slope direction, which is greater than the sum of the friction force between the conductive member 120 and the PCB board 110 and the viscous force generated by the molten tin between the conductive member 120 and the PCB board 110. In the case where the conductive member 120 is made of copper and is arranged in the above-mentioned rectangular parallelepiped shape, the area of ​​the cross section of the conductive member 120 perpendicular to the plane in contact with the PCB board 110 is, for example, greater than a certain value, for example, greater than 20 mm 2 In one embodiment of the present application, the cross-sectional area S of the rectangular conductive member parallel to the gravity direction and perpendicular to the PCB board satisfies the following formula:

[0024]

[0025] Wherein, f is the surface tension coefficient of the connection part after melting, g is the acceleration of gravity, and ρ is the density of the conductive part.

[0026] It should be understood that those skilled in the art can calculate the shape requirements that the conductive member 120 should meet based on the surface tension coefficient of tin, the friction coefficient between the conductive member 120 and the PCB board 110 , and the density of the conductive material used for the conductive member 120 .

[0027] refer to Figure 2 , which shows a schematic structural diagram of a thermal insurance mechanism 200 proposed in accordance with another embodiment of the present application. Figure 2 In the embodiment, the surface of the conductive member 220 facing the PCB board 210 includes a first welding surface 221 for the first conductor 230, a second welding surface 222 for the second conductor 240, and a sliding surface 223, the sliding surface 223 is arranged between the first welding surface 221 and the second welding surface 222, the first welding surface 221 and the second welding surface 222 are configured to be parallel to the plane of the PCB board 210, and the sliding surface 223 is configured to be an arched curved surface protruding toward the PCB board 210. In this embodiment, it is equivalent to setting a plane welding surface at the upper and lower ends of the PCB board 210 for welding the conductive member 220 with the first conductor 230 and the second conductor 240, and setting an arched curved surface in the middle to reduce the contact area between the conductive member 220 and the PCB board 210, in this way, the friction between the conductive member 220 and the PCB board 210 when sliding along the surface of the PCB board 210 can be reduced, so that the conductive member 220 can slide faster, and the reaction speed of the thermal insurance mechanism 200 is improved.

[0028] refer to Figure 3 and Figure 4 , which shows a schematic diagram of two different welding areas between the conductive member 120 and the first conductor 130 and the second conductor 140. Figure 3 and Figure 4 In the embodiment, the first conductor 130 and the second conductor 140 extend in the vertical direction of the vehicle, and the width of the welding area between the conductive member 120 and the first conductor 130 gradually decreases in the vertical direction of the vehicle. In this way, the contact area between the conductive member 120 and the first conductor 130 (i.e., the area where the molten tin exists) can be reduced faster during the process of the conductive member 120 sliding down the PCB board 110, so that the conductive member 120 can be separated from the first conductor 130 more quickly, accelerating the power-off process. Figure 3 In the embodiment, the lower end of the first conductor 130 is configured to be in the shape of an inverted triangle. Figure 4 In the embodiment, an inverted triangle notch is provided at the upper end of the conductive member 120. Both of these methods are equivalent to making the width of the contact area of ​​the conductive member 120 with the first conductor 130 gradually decrease during the falling process. In the embodiment not shown, the first conductor and the second conductor extend in a vertical direction perpendicular to the vehicle. In this case, the welding area between the conductive member and the first conductor and the second conductor can be configured to have a width that gradually decreases along the vertical direction of the vehicle. It should be understood that except Figure 3 and Figure 4 In addition to the shape design of the first conductor 130 and the conductive member 120 in the embodiment, those skilled in the art may also adopt other shape designs to meet the feature that the width of the welding area gradually decreases along the vertical direction of the vehicle, which should also be included in the scope of the present application.

[0029] Another aspect of the present application provides an electronic control unit 10, referring to Figure 5 , which shows a circuit diagram of an electronic control unit according to an embodiment of another aspect of the present application. The electronic control unit 10 is framed by dotted lines to distinguish it from a power source 20 (such as a vehicle battery) and an external power unit 30. The electronic control unit 10 includes a first conductor line 11, a second conductor line 12, the above-mentioned thermal insurance mechanism 100, and a housing 13 (in Figure 5 Not shown, see Figure 6 ), the first conductor line 11 is connected to the power source 20, the second conductor line 12 is connected to the external power unit 30, the first conductor line 11 and the second conductor line 12 are electrically connected through the thermal insurance mechanism 100, the first conductor 130 is a part of the first conductor line 11, and the second conductor 140 is a part of the second conductor line 12. It should be understood that Figure 2 The thermal safety mechanism 200 in the embodiment of the present invention can also be applied to Figure 5In the electronic control unit 10.

[0030] In an embodiment of another aspect of the present application, the electronic control unit 10 includes two parallel loops, each loop including a first conductor line 11 , a second conductor line 12 and a thermal insurance mechanism 100 .

[0031] refer to Figure 6 , which schematically shows the positional relationship between the housing 13 and the storage portion 131 of the electronic control unit 10 and the thermal insurance mechanism 100. A storage portion 131 opening upward is constructed at a position of the housing 13 below the conductive member 120 along the gravity direction of the conductive member 120, so as to accommodate the conductive member 120 that falls off from the PCB board 110 due to gravity. Generally, if the housing 13 is not provided with a storage portion 131, the conductive member 120 will fall onto the housing 13 of the electronic control unit 10 after falling off from the PCB board 110. The storage portion 131 opening upward is provided at a corresponding position of the housing 13 of the electronic control unit 10, so as to prevent the conductive member 120 from moving freely in the electronic control unit 10 after falling off. The shape of the storage portion 131 is, for example, configured to match the shape of the conductive member 120, for example corresponding to Figure 1 The conductive member 120 is configured to be in a box shape.

[0032] Another aspect of the present application provides a vehicle, wherein the vehicle includes the above-mentioned electronic control unit 10. When the thermal insurance mechanism is arranged in the vehicle, the PCB board is placed parallel to the vertical direction of the vehicle, so that when the vehicle is traveling on a horizontal road, the gravity direction of the conductive member is parallel to the vertical direction of the vehicle.

[0033] It should be understood that all the above preferred embodiments are illustrative rather than restrictive, and various modifications or variations made by those skilled in the art to the specific embodiments described above under the concept of the present application should be within the legal protection scope of the present application.

Claims

1. A thermal insurance mechanism for temperature protection of an electronic control unit circuit, comprising a PCB, a conductive member, and a first conductor and a second conductor arranged on the PCB at a distance from each other, wherein the conductive member is arranged close to the PCB and fixedly connected to the first conductor and the second conductor through a fusible connecting portion to be electrically connected to the first conductor and the second conductor respectively, characterized in that: When the PCB is arranged parallel to the gravity direction of the conductive member and the connecting portion is melted, the conductive member is disconnected from the electrical connection with at least one of the first conductor and the second conductor due to the action of gravity.

2. The thermal safety mechanism according to claim 1, characterized in that: The conductive member is respectively welded to the first conductor and the second conductor by soldering.

3. The thermal safety mechanism according to claim 2, characterized in that: The melting temperature of the connecting portion is between 210°C and 240°C.

4. The thermal safety mechanism according to claim 1, characterized in that: The conductive member is made of copper.

5. The thermal safety mechanism according to claim 4, characterized in that: The conductive member is configured in a rectangular parallelepiped shape, and is attached to the PCB board with its length direction parallel to the PCB board.

6. The thermal safety mechanism according to claim 5, characterized in that: The cross-sectional area S of the conductive member parallel to the gravity direction and perpendicular to the PCB board satisfies the following formula: Wherein, f is the surface tension coefficient of the connection part after melting, g is the acceleration of gravity, and ρ is the density of the conductive part.

7. The thermal safety mechanism according to claim 2, characterized in that: The surface of the conductive member facing the PCB board includes a first welding surface for the first conductor, a second welding surface for the second conductor, and a sliding surface, the sliding surface is arranged between the first welding surface and the second welding surface, the first welding surface and the second welding surface are configured to be parallel to the plane of the PCB board, and the sliding surface is configured to be an arched curved surface protruding toward the PCB board.

8. The thermal safety mechanism according to claim 2, characterized in that: The width of a welding area between the conductive member and at least one of the first conductor and the second conductor gradually decreases along a gravity direction of the conductive member.

9. An electronic control unit, characterized in that: The electronic control unit includes a first conductor line, a second conductor line, a thermal insurance mechanism according to any one of claims 1 to 8, and a shell, the first conductor line is connected to a power supply, the second conductor line is connected to an external power consumption unit, the first conductor line and the second conductor line are electrically connected through the thermal insurance mechanism, the first conductor is part of the first conductor line, and the second conductor is part of the second conductor line.

10. The electronic control unit according to claim 9, characterized in that: The electronic control unit includes two parallel circuits, each circuit including a first conductor line, a second conductor line and a thermal insurance mechanism.

11. The electronic control unit according to claim 9, characterized in that: A receiving portion opening upward is configured at a position of the housing below the conductive member along the gravity direction of the conductive member, so as to accommodate the conductive member falling off the PCB board due to gravity.

12. A vehicle, characterized in that: The vehicle comprises the electronic control unit according to any one of claims 9 to 11, and the PCB board is placed parallel to the vertical direction of the vehicle.

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