Fuse unit

Abstract

This fuse unit (1) comprises: a bus bar (3) that acts as a conductor and in which a section to be cut (3b) is set; a case body (2) that supports two points sandwiching the section to be cut; a cutting section (4) that is disposed in a first space (6) that is an internal space of the case body and is formed on one side with respect to the bus bar, the cutting section acting as an insulator; and a reconnection section (5) that is disposed in a second space (7) that is an internal space of the case body and is formed on the side of the bus bar opposite to the first space, the reconnection section acting as a conductor, wherein the cutting section has a tip section (4c) that cuts the bus bar into a first portion (14) and a second portion (15) at the section to be cut and is able to move into the second space, and the reconnection section has a first connection section (5b) that comes into contact with the first portion and a second connection section (5c) that comes into contact with the second portion.

Description

Technical Field

[0001] The present invention relates to the technical field of fuse units.

Background Art

[0002] A fuse unit that cuts off an electrical connection to ensure safety during abnormal occurrences is known. For example, in a vehicle having a high-voltage in-vehicle battery, a fuse unit is used to stop power supply from the in-vehicle battery in case of an accident.

[0003] In Patent Document 1 below, a configuration for protecting various electrical components and electrical circuits is disclosed by the fusible part of the fusible part unit melting to cut off the electrical circuit.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

Summary of the Invention

Problems to be Solved by the Invention

[0005] By the way, after the electrical connection is released by the fuse unit, there may be a case where it is desired to temporarily restore the electrical connection. For example, in a fuse unit mounted on a vehicle, when the fuse unit functions in case of an accident, the power supply from the in-vehicle battery is cut off and the safety of the passengers is ensured. However, leaving the accident vehicle at the accident site as it is may be dangerous, and there are cases where it is preferable to move the accident vehicle to a safe place before the arrival of a wrecker truck. In such a case, it is desirable to temporarily restore the electrical connection severed by the fuse unit.

[0006] This invention was made in view of these problems, and aims to propose a fuse unit that can release and restore electrical connections with a simple configuration. [Means for solving the problem]

[0007] A fuse unit according to one aspect of the present invention comprises a busbar which is made of a conductor and has a portion to be cut; a case body which supports two points on either side of the portion to be cut; a cut portion which is made of an insulator and is located in a first space formed in the internal space of the case body on one side of the busbar; and a reconnection portion which is made of a conductor and is located in a second space formed in the internal space of the case body on the opposite side of the busbar from the first space, wherein the cut portion has a tip portion which cuts the busbar into a first portion and a second portion and is movable in the second space, and the reconnection portion has a first connection portion which contacts the first portion and a second connection portion which contacts the second portion. As a result, the busbar is severed by the cutting section, disconnecting the electrical connection between the first and second parts, and then the electrical connection between the first and second parts is re-established by the reconnection section. [Effects of the Invention]

[0008] According to the fuse unit of the present invention, electrical connections can be released and restored with a simple configuration. [Brief explanation of the drawing]

[0009] [Figure 1] This is a schematic cross-sectional view showing an example of the configuration of a fuse unit according to an embodiment of the present invention. [Figure 2] This is a schematic perspective view showing a magnified view of the cut end of the fuse unit and the busbar. [Figure 3] This is a schematic diagram showing the busbar divided into a first and second part. [Figure 4] This is a schematic cross-sectional view showing an example of a fuse unit in a broken state. [Figure 5]This schematic cross-sectional view shows another example of a broken fuse unit, with both ends of the first and second sections in contact with the insulating part. [Figure 6] This is a schematic cross-sectional view showing an example of the reconnected state of a fuse unit. [Figure 7] This is a schematic cross-sectional view showing an example of a fuse unit of the first modified example. [Figure 8] This is a schematic cross-sectional view showing an example of a normal state of the fuse unit in the second modified example. [Figure 9] This is a schematic cross-sectional view showing an example of the reconnected state of the fuse unit in the second modified example. [Figure 10] This is a schematic cross-sectional view showing a portion of an example of a fuse unit of a third variant. [Modes for carrying out the invention]

[0010] An embodiment for implementing the fuse unit 1 of the present invention will be described below with reference to the attached diagram.

[0011] <1. Configuration of the fuse unit> Figure 1 shows an example of the configuration of the fuse unit 1 of the present invention. The fuse unit 1 is used to protect downstream components and reduce the risk of harm to people by disconnecting electrical connections upstream, closer to the power source. For example, in applications to vehicles, the fuse unit 1 could be installed near the vehicle battery or near the ECU (Electronic Control Unit) or other component to be protected.

[0012] The fuse unit 1 comprises a case body 2 in which a space is formed inside, a busbar 3 formed of a conductive material, a cutting section 4 for cutting the busbar 3, and a reconnection section 5 for restoring the electrical connection after the busbar 3 has been cut.

[0013] The case body 2 is formed of an insulator, and a bus bar 3 is disposed near the approximate center of the internal space of the case body 2. Inside the case body 2, there are a first space 6 formed on one side with respect to the bus bar 3 and a second space 7 formed on the side opposite to the first space 6 with respect to the bus bar 3.

[0014] In the following description, the direction in which the first space 6 and the second space 7 are arranged side by side is described as the vertical direction D1. Also, a plane perpendicular to the vertical direction D1 is described as a horizontal plane. However, the horizontal plane in the description does not necessarily need to be orthogonal to the gravitational direction when the fuse unit 1 is actually installed.

[0015] Also, the direction in which the bus bar 3 extends inside the fuse unit 1 is described as the left - right direction D2, and the direction orthogonal to the vertical direction D1 and the left - right direction D2 is described as the front - back direction D3. Of course, the left - right direction D2 and the front - back direction D3 in the description are also for convenience of explanation, and the installation direction when implementing the fuse unit 1 is not limited to these directions.

[0016] The first space 6 and the second space 7 may be cylindrical spaces, may be cubic - shaped spaces, or may be other spaces. In the following description, an example in which the first space 6 and the second space 7 are each cylindrical spaces is given.

[0017] A cutting portion 4 is disposed in the first space 6. The cutting portion 4 includes a large - diameter portion 4a having substantially the same size as the cross - section of the first space 6, a small - diameter portion 4b that is a portion continuous downward from the large - diameter portion 4a, and a cutting tip portion 4c that protrudes downward from the central portion of the small - diameter portion 4b. [[ID=二十二]]

[0018] As shown in FIG. 2, the cutting tip portion 4c has the shape of a triangular prism with its axial direction being the front - back direction D3, and the width in the left - right direction D2 becomes smaller as it goes downward.

[0019] The case body 2 has a support protrusion 2a formed near the approximate center in the vertical direction D1 on the inner peripheral surface of the first space 6.

[0020] Multiple support protrusions 2a may be provided on the inner surface of the first space 6 at circumferential intervals, or they may be provided in a continuous, annular shape in the circumferential direction.

[0021] The cut portion 4 is supported from below by the support projection 2a at the step at the boundary between the large diameter portion 4a and the small diameter portion 4b, thereby maintaining its position midway in the vertical direction D1 within the first space 6.

[0022] The first space 6 is separated into an upper space and a lower space when the cutting section 4 is positioned, and a mechanism for pushing the cutting section 4 downward in an emergency is located in the upper space. In this example, the ignition wire 8 and the gunpowder 9 placed at its tip are located in the upper space above the cutting section 4.

[0023] A reconnection section 5 is located in the second space 7. The reconnection section 5 is formed as a conductor and comprises a cylindrical base section 5a having approximately the same size as the cross-section of the second space 7, a first connection section 5b protruding upward from one end of the base section 5a in the left-right direction D2, and a second connection section 5c protruding upward from the other end of the base section 5a in the left-right direction D2. The vertical cross-section of the reconnection section 5 is roughly U-shaped.

[0024] The second space 7 is separated into an upper space and a lower space when the reconnection part 5 is positioned, and a spring member 10 for biasing the reconnection part 5 upward is positioned in the lower space. The spring member 10 is, for example, a compression coil spring.

[0025] The reconnection section 5 is provided as a flange section 5d that protrudes outward at the boundary between the base section 5a and the first connection section 5b and the second connection section 5c. The case body 2 has a movement restricting portion 2b formed in an inwardly convex shape near the approximate center in the vertical direction D1 on the inner circumferential surface of the second space 7.

[0026] The reconnection part 5, located in the second space 7, is restricted from moving further upward by the flange portion 5d engaging with the movement restricting portion 2b.

[0027] The inner surface of the first connection portion 5b of the reconnection portion 5, the inner surface of the second connection portion 5c, and the upper surface of the base portion 5a, specifically the portion between the first connection portion 5b and the second connection portion 5c, are formed as a recess 5e.

[0028] An insulating portion 11, formed of an insulator, is attached to the surface of the recess 5e.

[0029] In the lower space of the second space 7, a mechanism is arranged to push the reconnection part 5 upward. In this example, the ignition wire 12 and the gunpowder 13 placed at its tip are located in the lower space of the reconnection part 5.

[0030] The bus bar 3 comprises a thick-walled portion 3a located partially outside the case body 2, a thin-walled portion 3b located in the center of the case body 2 in the left-right direction D2 and directly below the cutting tip 4c of the cutting portion 4, and a connecting portion 3c that connects the thick-walled portion 3a and the thin-walled portion 3b.

[0031] The thin-walled portion 3b is provided as the portion to be cut, which will divide the busbar 3 into a first portion 14 and a second portion 15 when the cutting portion 4 falls and collides with it (see Figure 3).

[0032] The case body 2 is formed with a first restricting portion 16 that protrudes inward in the first space 6, which restricts the upward movement of the first portion 14 of the bus bar 3. Furthermore, the case body 2 is formed with a second restricting portion 17 that protrudes inward in the first space 6, which restricts the upward movement of the second portion 15 of the bus bar 3.

[0033] The first restricting portion 16 and the second restricting portion 17 may be integrally formed as a circumferentially continuous flange that protrudes inward in the first space 6.

[0034] <2. Conditions of each fuse unit> In addition to the normal state shown in Figure 1, the fuse unit 1 is capable of taking on a disconnected state in an emergency where a portion of the busbar 3 is disconnected and the electrical connection is severed, and a reconnected state where the electrical connection that was severed in the busbar 3 is restored.

[0035] Figure 4 shows an example of the fuse unit 1 being in a disconnected state.

[0036] When energy is applied to the gunpowder 9 via the ignition wire 8, the gunpowder 9 explodes. This instantly acts a strong downward force on the cutting section 4, causing the large-diameter section 4a to overcome the support projection 2a, and the cutting tip 4c to pierce the thin-walled section 3b of the busbar 3, causing the busbar 3 to break.

[0037] As shown in Figure 5, when the busbar 3 breaks, the tips of the first part 14 and the second part 15 may hang down and come into contact with the reconnection part 5.

[0038] Even in such cases, the electrical disconnection state between the first part 14 and the second part 15 is maintained because the insulating part 11 is attached to the surface of the recess 5e of the reconnection part 5.

[0039] Next, Figure 6 shows an example of the reconnected state of fuse unit 1.

[0040] When energy is applied to the gunpowder 13 via the ignition line 12, the gunpowder 13 explodes. This causes a strong upward force to act on the reconnection section 5, causing the flange section 5d to move over the movement restricting section 2b, the first connection section 5b to be pressed against the first section 14, and the second connection section 5c to be pressed against the second section 15.

[0041] In this case, as shown in each figure, the first restricting portion 16 is provided on the case body 2, which restricts the upward movement of the first portion 14 and increases the contact area between the first connecting portion 5b and the first portion 14. Similarly, the provision of the second restricting portion 17 on the case body 2 restricts the upward movement of the second portion 15, thereby increasing the contact area between the second connecting portion 5c and the second portion 15.

[0042] This suppresses an increase in contact resistance between the first connection part 5b and the first part 14, and an increase in contact resistance between the second connection part 5c and the second part 15, thereby ensuring good current flow between the first part 14 and the second part 15 of the busbar 3.

[0043] As shown in Figure 6, the length of the reconnection part 5 in the vertical direction D1 may be set such that the lower surface of the reconnection part 5 is supported from below by the movement restricting part 2b when the first connection part 5b and the second connection part 5c are pressed against the first part 14 and the second part 15, respectively. This makes it easier to maintain a state in which the first connecting portion 5b and the second connecting portion 5c are firmly pressed against the first portion 14 and the second portion 15, respectively.

[0044] <3. Variant> Figure 7 shows the first example of a variation. In this example, the fuse unit 1A does not have an insulating portion 11 in the recess 5e of the reconnection portion 5.

[0045] In this modified example, the reconnection section 5 is positioned below the busbar 3 at a distance from it, such that even if the tips of the broken first section 14 and second section 15 hang down (indicated by the dashed line in Figure 7), they will not reach them.

[0046] This prevents the first part 14 and the second part 15 from becoming electrically connected via the reconnection part 5 when the fuse unit 1A is disconnected. Furthermore, the number of parts can be reduced by not providing the insulating section 11.

[0047] A second example of a variation is shown in Figure 8. In this modified example, the fuse unit 1B differs from the example described above in the shape of the case body 2B, the shape of the busbar 3B, and the shape of the reconnection part 5B.

[0048] First, the busbar 3B has a thick section 3a, a thin section 3b, and a connecting section 3c, but the portions located in the first space 6 and the second space 7 are approximately the thin section 3b.

[0049] The reconnection section 5B, located in the second space 7 below the busbar 3B, comprises a cylindrical base 5f, a first connection section 5b that protrudes upward from near one end of the base 5f in the left-right direction D2 and has a conical tip, and a second connection section 5c that protrudes upward from near the other end of the base 5f in the left-right direction D2 and has a conical tip.

[0050] The upper part of the base 5f is formed as a protruding engaging portion 5g that protrudes at least in the left-right direction D2. The protruding engaging portion 5g is positioned above the movement restricting portion 2b of the case body 2B, thereby restricting the downward movement of the reconnecting portion 5B (for example, movement due to gravity). Unlike the other examples described above, the reconnection section 5B is not subjected to an upward force by the spring member 10 or the like.

[0051] Furthermore, a second movement restricting portion 2c is formed slightly above the portion of the inner circumferential surface of the second space 7 of the case body 2B where the protruding engaging portion 5g is in contact, thereby restricting the upward movement of the reconnecting portion 5B.

[0052] In other words, the reconnection part 5B is held in a state where the protruding engaging part 5g is sandwiched between the movement restricting part 2b and the second movement restricting part 2c, thereby restricting its movement in the vertical direction D1.

[0053] Furthermore, the case body 2B is not provided with a first restricting section 16 that restricts the upward movement of the first section 14 of the bus bar 3B, nor a second restricting section 17 that restricts the upward movement of the second section 15.

[0054] Figure 9 shows the reconnected state of fuse unit 1B in this modified example. As shown in the figure, when the reconnection section 5B is moved upward with a strong force by detonating the gunpowder 13 via the ignition line 12, the first connection section 5b of the reconnection section 5B penetrates the first portion 14 of the broken busbar 3B, and the second connection section 5c penetrates the second portion 15.

[0055] First connection part 5b and Second connection part 5c The conical shape of the tip allows the first connecting portion 5b and the second connecting portion 5c to easily penetrate the first portion 14 and the second portion 15.

[0056] Furthermore, the first connecting portion 5b and the second connecting portion 5c may be provided with a return to facilitate the maintenance of a state in which they penetrate the first portion 14 and the second portion 15.

[0057] Furthermore, in order to facilitate the passage of the first connecting portion 5b and the second connecting portion 5c through the first portion 14 and the second portion 15, respectively, restricting portions may be provided to restrict the upward movement of the first portion 14 and the second portion 15. It is desirable that the restricting portion be provided so as not to interfere with the tip of the first connecting portion 5b and the tip of the second connecting portion 5c when they are in a penetrating state.

[0058] Furthermore, to prevent the first connecting portion 5b and the second connecting portion 5c from interfering with the cutting portion 4 that has fallen from above, a retraction hole may be formed in the cutting portion 4 to allow the tip of the first connecting portion 5b, which has penetrated the first portion 14, to move out of the way. Similarly, the cutting portion 4 may be provided with a retraction hole to allow the tip of the second connecting portion 5c, which has penetrated the second portion 15, to move out of the way.

[0059] Furthermore, in order to prevent excessive downward movement of the cutting portion 4, specifically to prevent downward movement of the cutting portion 4 to the extent that it would obstruct the upward movement of the reconnection portion 5 after the busbar 3 has been cut, a restricting portion may be provided on the inner circumferential surface of the first space 6 of the case body 2B.

[0060] According to this modified version, the first restricting portion 16 and the second restricting portion 17, as well as the spring member 10, etc., are not provided in the case body 2B, thereby reducing the weight of the fuse unit 1B.

[0061] A third example of a variation is shown in Figure 10. In this modified example, the shape of the cut portion 4C of the fuse unit 1C differs from that of the example described above.

[0062] Specifically, the cutting portion 4C does not have a large diameter portion 4a and a small diameter portion 4b, but has a cylindrical portion 4d, a protruding portion 4e that projects outward from approximately the center in the vertical direction D1 of the cylindrical portion 4d, and a cutting tip portion 4c.

[0063] Because there is no large-diameter portion 4a which is approximately the same diameter as the first space 6, the frictional resistance between the cut portion 4 and the case body 2 is minimized after the protruding portion 4e overcomes the support projection 2a and is positioned below it during the transition process from the normal state to the cut state. Therefore, it becomes possible to break the busbar 3 with the cutting tip 4c of the cutting section 4 using less gunpowder 9.

[0064] A similar configuration can also be applied to the reconnection unit 5.

[0065] In the examples described above, a spring member 10 acting as a compression spring was used below the reconnection section 5. However, a spring member acting as a tension spring may be provided above the reconnection section 5. In that case, the movement restricting section 2b of the case body 2 should be provided in a position and shape that restricts the upward movement of the reconnection section 5.

[0066] <4. Summary> As described in the examples above, the fuse unit 1 (1A, 1B, 1C) according to the present invention comprises a bus bar 3 (3B) which is made of a conductor and has a cut portion (thin-walled portion 3b), a case body 2 (2B) which supports two points on either side of the cut portion, a cut portion 4 (4C) which is made of an insulator and is located in a first space 6 formed in the internal space of the case body 2 (2B) on one side of the bus bar 3 (3B), and a reconnection portion 5 (5B) which is made of a conductor and is located in a second space 7 formed in the internal space of the case body 2 (2B) on the opposite side of the bus bar 3 (3B) from the first space 6. Furthermore, the cutting portion 4(4C) has a cutting tip 4c that cuts the busbar 3(3B) into a first portion 14 and a second portion 15 at the portion to be cut, and is movable within the second space 7. The reconnection portion 5(5B) has a first connecting portion 5b that contacts the first portion 14 and a second connecting portion 5c that contacts the second portion 15. As a result, the busbar 3(3B) is severed by the cutting section 4(4C), and the electrical connection between the first section 14 and the second section 15 is broken. Then, the electrical connection between the first section 14 and the second section 15 is re-established by the reconnection section 5(5B). For example, by applying the fuse unit 1 (1A, 1B, 1C) of the present invention to a vehicle, after the busbar 3 (3B) is cut to avoid secondary damage due to electrical leakage in the event of an accident, the electrical connection of the busbar 3 (3B) can be restored, allowing for the movement of the vehicle to ensure safety at the accident site. Furthermore, in extremely low temperatures, it is conceivable that occupants would remain inside the wrecked vehicle, seeking warmth while waiting for rescue. However, by restoring the electrical connection of busbar 3 (3B), it becomes possible to use the vehicle's battery power to provide air conditioning inside the vehicle, thereby improving the chances of occupant survival.

[0067] In the fuse unit 1 (1B, 1C) according to the present invention, the reconnection portion 5 (5B) is U-shaped, with the first connection portion 5b and the second connection portion 5c formed to protrude toward the bus bar 3 (3B), and an insulating portion 11 may be provided in the U-shaped recess 5e of the reconnection portion 5 (5B). As a result, even if both ends of the first portion 14 and the second portion 15 of the broken busbar 3 (3B) come into contact with the reconnection portion 5 (5B), the portion where both ends come into contact will be insulated 11. Therefore, it is possible to prevent the electrical connection between the first portion 14 and the second portion 15 from being unintentionally restored, thereby improving safety. Furthermore, by providing the insulating portion 11 in the recess 5e and not at the tips of the first connection portion 5b and the second connection portion 5c, it is possible to prevent the restoration of the electrical connection between the first portion 14 and the second portion 15 from being hindered.

[0068] The case body 2 in the fuse unit 1 (1A, 1C) according to the present invention may include a first restricting portion 16 that restricts the movement of the first portion 14 toward the first space 6, and a second restricting portion 17 that restricts the movement of the second portion 15 toward the first space 6. As a result, when the first connecting portion 5b and the second connecting portion 5c are pressed against the first portion 14 and the second portion 15, respectively, the movement of the first portion 14 and the second portion 15 toward the first space 6 is restricted, ensuring a good connection. Therefore, the electrical connection between the first part 14 and the second part 15 can be restored effectively. Furthermore, the contact area between the first part 14 and the first connecting part 5b, and the contact area between the second part 15 and the second connecting part 5c can be increased, thereby suppressing an increase in contact resistance and reducing power consumption.

[0069] In the fuse unit 1 (1A, 1C) according to the present invention, a spring member 10 is provided to bias the reconnection part 5 in a direction toward the bus bar 3, and the case body 2 may be provided with a movement restricting part 2b that restricts the movement of the reconnection part 5 toward the bus bar 3. As a result, simply by releasing the restriction imposed by the movement restriction unit 2b, the first connection unit 5b and the second connection unit 5c in the reconnection unit 5 are pressed against the first part 14 and the second part 15, respectively, thereby restoring the electrical connection between the first part 14 and the second part 15. Therefore, motor drive or the like is not required to bring the first connection part 5b and the second connection part 5c into contact with the first part 14 and the second part 15 during reconnection. Various configurations of the movement restricting section 2b are conceivable. For example, the movement restricting section 2b may be configured to be able to switch between a state where it protrudes from the inner wall of the case body 2 and a state where it is retracted. In that case, it is not necessary to place the explosive 13 below the reconnection section 5, which contributes to improved safety.

[0070] In the fuse unit 1 (1A, 1C) according to the present invention, the spring member 10 may be biased in a direction that brings the reconnection portion 5 closer to the bus bar 3 (3B) when the first connection portion 5b is in contact with the first portion 14 and the second connection portion 5c is in contact with the second portion 15. As a result, after reconnection, the state in which the first connection part 5b is pressed against the first part 14 and the second connection part 5c is pressed against the second part 15 continues. Therefore, the electrical connection between the first part 14 and the second part 15 after reconnection can be continuously ensured.

[0071] The embodiments and variations described above can be combined as appropriate. [Explanation of symbols]

[0072] 1, 1A, 1B, 1C fuse unit 2, 2B Case 2b Movement control section 3, 3B bus bar 3b Thin wall part (part to be cut) 4, 4C cutting section 4c Cutting tip 5, 5B Reconnection section 5b First connection section 5c Second connection section 5e recess 6 1st space 7 Second space 10 Spring component 11 Insulation 14 Part 1 15 Part 2 16. First Regulatory Department 17 Second Regulatory Section

Claims

1. A busbar which is made of a conductive material and has a cut-off section, A case body that supports the two points on either side of the portion to be cut, A cut portion, which is an insulator, is located in the first space formed on one side of the busbar within the internal space of the case body, The case body comprises a second space formed in the internal space of the case body on the opposite side of the first space in the busbar, and a reconnection part which is made of a conductor, The cutting portion has a tip portion that cuts the busbar into a first portion and a second portion in the portion to be cut and is movable within the second space, The reconnection portion has a first connecting portion that contacts the first portion and a second connecting portion that contacts the second portion. Fuse unit.

2. The reconnection portion is U-shaped, with the first and second connection portions projecting toward the busbar. An insulating portion is provided in the U-shaped recess of the reconnection portion. The fuse unit according to claim 1.

3. The case body comprises a first restricting portion that restricts movement of the first portion toward the first space, and a second restricting portion that restricts movement of the second portion toward the first space. The fuse unit according to claim 1.

4. The reconnection portion is provided with a spring member that biases it in a direction toward the busbar, The case body includes a movement restricting section that restricts movement of the reconnection section toward the busbar. The fuse unit according to claim 1.

5. The spring member biases the reconnection portion toward the busbar when the first connection portion is in contact with the first portion and the second connection portion is in contact with the second portion. The fuse unit according to claim 4.

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