Interlock mechanism with fuse function

Abstract

This invention provides a fuse-equipped interlock mechanism that is miniaturized and reusable, without the need for large fuses. [Solution] The interlock mechanism 1 consists of a male interlock terminal 10 and a female interlock terminal 20, and is installed in a position where the temperature rises due to the heat generated from the electrical connector. The male interlock terminal 10 comprises a gate-shaped terminal member 11, a fixing member 12 fixed at both ends, and a shut-off pin 13 that expands as the temperature rises. The tip 111 of the gate-shaped terminal member 11 can pass through the fixing member 12 and come into contact with or be separated from the tip 201 of the female interlock terminal 20. The shut-off pin 13 is located inside the gate 14 of the gate-shaped terminal member 11, with one end 131 supported by the upper surface 121 of the fixing member 12 and the other end 132 in contact with the upper inner surface 112 of the gate-shaped terminal member. The coefficient of linear expansion αp of this shut-off pin 13 is set to be larger than the coefficient of linear expansion αt of the gate-shaped terminal member 11.

Description

Technical Field

[0001] The present invention relates to an interlock mechanism with a fuse function.

Background Art

[0002] Hybrid vehicles and electric vehicles have a DC power source, an inverter, and a motor driven by the inverter, and obtain a power source by converting the DC voltage from the DC power source into an AC voltage by the inverter and rotating the motor by the converted AC voltage. In the EV systems of hybrid vehicles and electric vehicles, since a relatively large current flows through internal units and wiring, a fuse-equipped electrical connector may be used to ensure safety and prevent damage to components. The fuse is provided inside the connector or on the unit terminal block. However, with the recent trend towards higher power (higher current), the fuse has become larger, and the connector and unit terminal block are also tending to become larger.

[0003] Therefore, in Patent Document 1, an electrical connector with a fuse function having the function of a fuse is disclosed without using a large fuse. That is, this electrical connector includes a connector terminal through which current flows, an interlock terminal that detects the connection of the connector terminal, and a housing that holds the connector terminal and the interlock terminal. The melting point of the material of the housing is set higher than the melting point of the material of the interlock terminal. When an overcurrent flows through the connector terminal, the temperature that rises due to the heat generation is transmitted to the interlock terminal through the housing. When the temperature reaches a predetermined temperature equal to or higher than the melting point of the interlock terminal, the interlock terminal is melted and the energization of the connector terminal is stopped.

Prior Art Documents

Patent Documents

[0004]

Patent Document 1

[0005] According to the electrical connector described in Patent Document 1, a fuse function can be achieved without using a large fuse, and the size of the electrical connector can be reduced. However, if the interlock terminal melts, heat is generated in the narrow, confined space, which may cause thermal damage to surrounding components. Furthermore, once the interlock terminal melts, its function cannot be restored, and the entire electrical connector had to be replaced.

[0006] This invention was made in view of the above-mentioned technical problems, and the object of this invention is to provide an interlock mechanism with a fuse function that can reduce the size of the connector without using a large fuse, and that can also repeatedly utilize the fuse function. [Means for solving the problem]

[0007] To achieve the above objective, the present invention provides an interlock mechanism used to detect whether or not an electrical connector is electrically connected, wherein a male interlock terminal and a female interlock terminal are provided at positions where their temperature rises due to heat generated from the electrical connector, the male interlock terminal comprises a terminal member, a fixing member fixed at both ends to a housing, and a blocking member that expands as the temperature rises, the tip of the terminal member can contact or separate from the female interlock terminal, the blocking member is located inside the terminal member, one end is supported by the fixing member and the other end abuts against the terminal member, and the coefficient of linear expansion of the blocking member is set to be greater than that of the terminal member. [Effects of the Invention]

[0008] The fuse-function interlock mechanism of the present invention consists of a terminal member, a fixing member, and a blocking member. The terminal member is movable up and down, and its tip moves in and out of contact with a female interlock terminal. On the other hand, the blocking member is positioned inside the terminal member. One end (lower end) of the blocking member is supported by a fixing member fixed to the housing, and the other end (upper end) is in contact with the terminal member. Thus, initially, the tip of the terminal member is positioned in contact with the tip of the female interlock terminal. Meanwhile, the coefficient of linear expansion of the material of the blocking member is set to be greater than that of the material of the terminal member. Therefore, when the temperature rises, the amount of expansion of the blocking member exceeds the amount of expansion of the terminal member, and a force due to the expansion of the blocking member is generated between the fixing member and the terminal member. Since one end of the blocking member is supported and fixed by the fixing member, this force due to expansion acts on the contact portion on the other end, and ultimately acts as a force that pushes up the terminal member.

[0009] With the above configuration, when an overcurrent flows through the electrical connector, the heat is transferred to the terminal member and the interrupting member, causing their temperature to rise. As the temperature of these members rises, the amount of extension of the interrupting member is greater than the amount of extension of the terminal member, so it pushes the terminal member upward. As a result, the tip of the terminal member separates from the tip of the female interlock terminal, interrupting the current flow, and the electrical connector stops powering in response to this signal. In this way, the overcurrent is interrupted and the fuse function is activated. Afterwards, as the temperature drops, the interrupting member and other components also contract, so the tip of the terminal member can once again contact the female interlock terminal and the original power-conducting state can be restored. As described above, the present invention provides an interlock mechanism with a fuse function that allows for miniaturization of the size of the electrical connector without using a fuse that melts, and also allows for repeated use of the fuse function. [Brief explanation of the drawing]

[0010] [Figure 1] This block diagram shows an example of an EV system that uses electrical connectors. [Figure 2]The present invention relates to an interlock mechanism with a fuse function, wherein (a) is a schematic diagram showing the interlock mechanism in a closed state, and (b) is a schematic diagram showing the interlock mechanism in an open state. [Figure 3] This is a perspective view showing an embodiment of an electrical connector. [Figure 4] An interlock mechanism with fuse function according to another embodiment of the present invention, showing the engagement state of a fixed member and a cutting member, where (a) is a schematic diagram showing the engaged state and (b) is a schematic diagram showing the disengaged state. [Figure 5] This is a schematic diagram showing a closed state of an interlock mechanism with a fuse function according to another embodiment of the present invention. [Modes for carrying out the invention]

[0011] Embodiments of the present invention will be described with reference to the accompanying drawings. In the drawings, the same or corresponding parts will be denoted by the same reference numerals, and redundant explanations will be omitted. The embodiments described below are merely examples of how the present invention can be carried out and do not limit the present invention.

[0012] Figure 1 is a block diagram showing an example of an EV system in which an electrical connector 2 is used. In this embodiment, the case in which an electrical connector 2, consisting of a male connector 30 and a female connector 40, is used to connect an inverter 52 and a high-voltage battery 51 will be explained as an example. Note that the electrical connector 2 may also be used to connect, for example, an inverter 52 and an electric motor 53. Furthermore, in this invention, all connectors used for electrical connections, including low-voltage connectors and high-voltage connectors, are collectively referred to as electrical connectors. The following will describe the EV system's overview along with the configuration of its electrical connectors, followed by a description of the interlock mechanism.

[0013] The electric motor 53 is configured here as a synchronous regenerative motor that combines the function of a motor that converts supplied electricity into mechanical power and the function of a generator that converts input mechanical power into electricity. In other words, the electric motor 53 (hereinafter also referred to as "motor-generator") operates as a motor that generates driving torque when the vehicle is driven, and operates as a generator when regenerating power. The high-voltage battery 51 is configured as a high-voltage battery of tens to hundreds of volts, for example, by connecting several tens to over a hundred battery cells in series. Lithium-ion batteries are preferably used as the battery cells. However, rechargeable secondary batteries such as nickel-cadmium batteries can also be used instead of lithium-ion batteries.

[0014] The motor-generator 53 is comprehensively controlled by an electric vehicle-control unit (EV-CU) 50. The EV-CU 50 determines and outputs a torque command value for the motor-generator 53 based on driving conditions such as the opening of the accelerator pedal, the vehicle speed, and the charge state of the high-voltage battery 51. Here, an interlock mechanism 1 (the interlock mechanism of the present invention) is connected to the EV-CU 50 via an interlock line 20a for detecting the mating state, i.e., the electrical connection state, between the male connector 30 and the female connector 40. Depending on the state of the interlock mechanism 1 (closed or open), the EV-CU 50 permits or stops the supply of power from the high-voltage battery 51 to the inverter 52. The inverter 52 is electrically connected to the motor-generator 53 by a three-phase cable 40c. Based on the torque command value, the inverter 52 converts the DC power from the high-voltage battery 51 into three-phase AC power and supplies it to the motor-generator 53 to drive the motor-generator 53. On the other hand, during regeneration, the inverter 52 converts the AC voltage generated by the motor-generator 53 into DC voltage to charge the high-voltage battery 51.

[0015] In the electrical connector 2, the male connector 30 is configured by mounting a pair of male connector terminals 31 in a male connector housing 32. A cable 40b connected to the inverter 52 is electrically connected to each of the male connector terminals 31. Further, in the male connector housing 32, a male interlock terminal 10, which will be described later, is mounted in proximity to the male connector terminals 31. The male connector housing 32 holds the male connector terminals 31 and the male interlock terminal 10, and is provided in proximity so as to easily transfer heat between the male connector terminals 31 and the male interlock terminal 10, and is made of a material having a high melting point and high thermal conductivity. More specifically, an epoxy resin-based material (for example, a thermosetting resin of polyimide / epoxy resin blended with an inorganic filler excellent in heat transfer) having both high electrical insulation, high thermal conductivity, and high heat resistance is preferably used.

[0016] In the electrical connector 2, the female connector 40 is configured by mounting a pair of female connector terminals 41 in a female connector housing 42. A cable 40a connected to the high-voltage battery 51 is electrically connected to each of the female connector terminals 41. Further, in the female connector housing 42, a female interlock terminal 20, which will be described later, is mounted in proximity to the female connector terminals 41. Similar to the male connector housing 32, the female connector housing 42 is preferably made of a material having a high melting point and high thermal conductivity. The same material as the above-described male connector housing 32 may be used as the specific material, but the female connector 40 may be selected according to the case because it is mounted on the case of the high-voltage battery 51.

[0017] As described above, the male connector 30 and the female connector 40 are configured to be electrically connectable. Normally, the male connector terminal 31 and the female connector terminal 41 are configured to be matingly engageable. At the same time, the male interlock terminal 10 and the female interlock terminal 20 are configured to be electrically connectable. Regarding the specific connection structure, although it will be described later, it may be a fitting connection by ordinary unevenness. Anyway, when the male connector terminal 31 and the female connector terminal 41 are connected, the male interlock terminal 10 and the female interlock terminal 20 are also connected, and the respective terminals are electrically connected. As a result, the high-voltage battery 51 and the inverter 52 are electrically connected via the electrical connector 2, and the interlock mechanism 1 is connected. The interlock mechanism 1 is for detecting whether the electrical connector 2 is electrically connected. When the EV-CU 50 detects that the interlock mechanism 1 is connected (the interlock circuit is in a closed state), energization of the electrical connector 2 is permitted. On the other hand, when the EV-CU 50 detects that the connection of the interlock mechanism 1 is released (the interlock circuit is in an open state), energization to the electrical connector 2 is prohibited, and energization from the high-voltage battery 51 to the inverter 52 is stopped.

[0018] Next, the interlock mechanism of the present invention will be described with reference to FIG. 1 and using FIG. 2. FIG. 2 is an interlock mechanism with a fuse function, where (a) is a schematic diagram showing the state where the interlock mechanism is closed, and (b) is a schematic diagram showing the state where the interlock mechanism is opened.

[0019] In the figure, the interlock mechanism 1 consists of a male interlock terminal 10 and a female interlock terminal 20, and is provided close to the electrical connector described above. This is to ensure that the heat generated when an overcurrent flows through the electrical connector is steadily transmitted, the surrounding temperature rises without delay, and the temperature of the terminal member and the cutoff pin described below also rises. The male interlock terminal 10 consists of a terminal member (in this example, a gate-shaped terminal member is used, so hereinafter referred to as the "gate-shaped terminal member") 11, a fixing member 12 fixed to a housing or the like at both ends, and a blocking member (in this example, a blocking pin is used, so hereinafter referred to as the "blocking pin") 13 that expands as the temperature rises. The legs 114 (both legs) of the gate-shaped terminal member 11 pass through the holes 122 of the fixing member 12, and their tips 111 are in contact with the tips 201 of the female interlock terminal 20. The gate-shaped terminal member 11 is movable up and down relative to the fixing member 12, and its tips 111 can also contact and separate from the tips 201 of the female interlock terminal 20. It is desirable to magnetize the tips or incorporate a magnetic material to attract them by magnetic function in order to strengthen the contact force between the tips 111 of the gate-shaped terminal member 11 and the tips 201 of the female interlock terminal 20.

[0020] On the other hand, the interruption pin 13 is positioned upright inside the gate (inside the gate) 14 of the gate-shaped terminal member 11. One end (lower end) 131 of the interruption pin 13 is placed on the upper surface 121 of the fixing member 12, and the other end (upper end) 132 is positioned to contact the upper inner surface 112 of the gate-shaped terminal member 11. In other words, since both ends of the fixing member 12 are fixed to the housing, one end of the interruption pin 13 is supported by the fixing member 12, and the other end is positioned by contacting the gate-shaped terminal member. If the length of the interruption pin 13 is extended, the force due to this extension will act as a reaction force on the contact point on the inner surface 112 of the gate-shaped terminal member 11 on the other end side, since one end 131 of the interruption pin 13 is supported and fixed on the upper surface 121 of the fixing member 12. As a result, it acts as a force that pushes the gate-shaped terminal member 11 upward.

[0021] The interruption pin 13 is made of a material that expands more as the temperature rises than other components such as the gate-type terminal member 11 and the fixing member 12. As mentioned above, it is preferable to use a material that reliably transfers the heat generated when an overcurrent flows, causing the temperature to rise immediately. Since conductivity is required for the gate-type terminal member 11 and the interruption pin 13, metal materials are used, but it is important to select a material in which the linear expansion coefficient αp of the interruption pin 13 is greater than the linear expansion coefficient αt of the gate-type terminal member 11. For example, the interruption pin may be made of aluminum (23.5 × 10 -6 ( / ℃) and copper alloys (16.5~19.0×10 -6 The gate-shaped terminal member is made of iron (11.7 × 10°C), and the gate-shaped terminal member is made of iron (11.7 × 10°C). -6 / ℃) and stainless steel (9.9~10.4×10 -6 It is conceivable that the terminals be formed at a temperature of ( / °C). While these materials are not limited, ferritic stainless steel (such as SUS430) is preferable as a terminal material because it is magnetic and has a low coefficient of thermal expansion. The interruption pin may be made of an elastic body such as a spring, and copper alloy is preferable as a material for the interruption member because it is easy to process. Furthermore, it is preferable that the difference Δα between the coefficient of thermal expansion of the gate-type terminal member 11 and the interruption pin 13 is large. The larger Δα is, the greater the extension of the interruption pin 13 is than the extension of the gate-type terminal member 11, which is advantageous for separating the tip 111 of the gate-type terminal member 11 from the tip 201 of the female interlock terminal 20. Figure 2(a) shows the state in which the tip 111 of the gate-type terminal member and the tip 201 of the female-type interlock terminal are in contact, and the interlock mechanism is closed. Therefore, the EV-CU50 detects that it is in a closed state via the interlock line 20a, and power to the electrical connector 2 is permitted.

[0022] With the above configuration, when an overcurrent flows through the electrical connector, the heat generated is transmitted to the gate-type terminal member 11 and the interruption pin 13, causing their temperatures to rise. As the temperatures of these components rise, the difference in their coefficients of thermal expansion (Δα) causes the interruption pin 13 to elongate more than the gate-type terminal member 11, resulting in the interruption pin 13 extending by Δl. This force pushes up the gate-type terminal member 11, causing the tip 111 of the gate-type terminal member and the tip 201 of the female-type interlock terminal to separate by a gap s, as shown in Figure 2(b). At this point, the interlock mechanism is in an open state, which is detected by the EV-CU 50 via the interlock circuit 20a, and the power supply to the electrical connector 2 is cut off. Subsequently, as the temperature drops, the shut-off pins and other components also contract, causing the tip 111 of the gate-type terminal member 11 to contact the tip 201 of the female-type interlock terminal 20 again. When this happens, the EV-CU 50 detects that the interlock mechanism is in the closed state, and power to the electrical connector 2 is permitted, allowing it to return to its original energized state.

[0023] Next, Figure 3 is a perspective view showing an embodiment of an electrical connector. In the figure, the same or equivalent parts are denoted by the same reference numerals, so their explanation is omitted. As shown in the figure, the electrical connector 2 is composed of a male connector 30 and a female connector 40, and the fuse-function interlock mechanism 1 is composed of a male interlock terminal 10 consisting of a gate-type terminal member 11, a fixing member 12 and a shut-off pin 13, and a female interlock terminal 20. Inside the male connector housing 32, a pair of male connector terminals 31 and the male interlock terminal 10 are arranged adjacent to them. On the other hand, inside the female connector housing 42, a pair of female connector terminals 41 and the female interlock terminal 20 are arranged adjacent to them. Therefore, when the male connector terminals 31 and the female connector terminals 41 are mated together, the male interlock terminal 10 and the female interlock terminal 20 come into contact and are electrically connected. As mentioned above, the male interlock terminal 10 and the female interlock terminal 20 may also be configured to be mated together. As described above, this electrical connector allows for miniaturization without the need for large fuses, and also enables repeated use of the fuse function.

[0024] In the interlock mechanism of the present invention, the coefficient of thermal expansion of the terminal member and the coefficient of thermal expansion of the interrupting member can be determined based on the temperature rise caused by the heat generated when an overcurrent flows through the electrical connector, and the materials can be selected accordingly. For example, the amount of heat generated (or intended to be generated) when an overcurrent flows through the male connector 30 and the female connector 40, and the temperature difference ΔT between the terminal member and the interrupting member, which rises due to this heat, can be obtained in advance. Also, the amount of extension Δl of the interrupting member can be set from the gap s required to separate the male interlock terminal and the female interlock terminal. Then, using ΔT, Δl, and the length l of the interrupting member, the coefficient of thermal expansion αp of the interrupting member can be determined from the formula α = Δl / l·ΔT, and a material that satisfies this coefficient of thermal expansion αp can be selected. Furthermore, since the electrical resistance of the electrical connector is set based on the amount of heat generated, by adjusting (increasing) the electrical resistance R of the male and female connectors, the amount of heat generated when an overcurrent I flows (I 2 It is also possible to adjust (increase) R). For example, the electrical resistance of an electrical connector can be set higher than usual to increase the amount of heat generated when an overcurrent flows through the male and female connectors.

[0025] Next, an interlock mechanism with a fuse function according to another embodiment of the present invention will be described with reference to Figure 4. Figure 4 shows the engagement state of a fixed member and a blocking member (a blocking pin is used in this example as well), where (a) is a schematic diagram showing the engaged state and (b) is a schematic diagram showing the disengaged state. In this example, a recessed hole 150 is formed in the upper part of the fixing member 15, and a recessed portion 151 is provided on the inner circumferential surface of this recessed hole 150. On the other hand, a projection 161 is provided on one end 160 of the interruption pin 16. This projection 161 may be formed around the entire circumference, there may be only one, or there may be multiple projections intermittently arranged. With this configuration, when the end 160 of the interruption pin 16 is fitted into the recessed hole 150 of the fixing member 15, the projection 161 fits into the recessed portion 151 and becomes engaged. In this engaged state, the positioning of the interruption pin 16 is stably performed. When an overcurrent flows through the electrical connector, as described above, the interruption pin 16 extends, pushing up the gate-type terminal member 11, and the engagement between the projection 161 and the recessed portion 151 is released, creating a gap s, and the interlock mechanism opens. Furthermore, in this state, the engaging portion c has its projection 161 resting on the recessed hole 150 (including the indentation), preventing the projection 161 from returning to the indentation 151. Subsequently, as the temperature drops, the shut-off pin and other components also contract, allowing the shut-off pin to be pushed back in by hand to return to a contact state. In this way, the fuse function can be used repeatedly.

[0026] Next, Figure 5 is a schematic diagram showing an interlock mechanism with a fuse function relating to yet another embodiment, in which the interlock mechanism is in a closed state. In this example, an elastic member, in this case a spring member 17, is provided between the upper outer surface 113 of the gate-type terminal member 11 and the housing such as the male connector housing 32, which presses the gate-type terminal member 11 toward the fixing member 12. With this configuration, the spring member 17 presses the gate-type terminal member 11 downward, ensuring that its tip 111 makes contact with the tip 201 of the female interlock terminal 20. When an overcurrent flows through the electrical connector, the interruption pin 16 extends as described above, pushing the gate-type terminal member 11 upward against the spring force, creating a gap s between the tip 111 and the tip 201, and the interlock mechanism opens. Subsequently, as the temperature drops, the interruption pin and the like also contract, and the added spring force presses the gate-type terminal member downward, returning the interlock mechanism to a closed state.

[0027] Although embodiments of the present invention have been described above, the present invention is not limited to the embodiments described above and can be implemented with appropriate modifications as needed. For example, the location where the interlock mechanism with fuse function is applied is not limited to the embodiments described above, and it may also be installed in a location where heat is transmitted, such as a busbar or a heat-generating component exposed to high temperatures. In an EV system, it may be used for the connection between an inverter and an electric motor (motor-generator), or for the connection between other control units and cables. Furthermore, a high thermal conductivity material, which has a higher thermal conductivity than the male or female connector housing, may be separately provided between the male connector terminal and the male interlock terminal. In this way, the heat generated at the male connector terminal when an overcurrent flows can be transferred to the male interlock terminal more efficiently.

[0028] Furthermore, in this embodiment, the interlock mechanism with fuse function is provided on the male interlock terminal side, but it may also be provided on the female interlock terminal side. Also, the connection structure between the male and female interlock terminals may be a conventional mating structure with the ends of each terminal formed with protrusions and recesses, or it may be a structure using magnetic force. Furthermore, although this embodiment shows an interlock mechanism with a fuse function used in an EV system as an example, the present invention can also be applied to other electrical systems that require an interlock mechanism, such as trains and industrial machinery. [Explanation of Symbols]

[0029] 1: Interlock mechanism with fuse function 2: Electrical connector 10: Male interlock terminal 11: Terminal members (gate-type terminal members) 111: Tip of gate-type terminal member 112: Upper inner surface of gate-type terminal member 113: Upper outer surface of gate-type terminal member 114: Legs of gate-type terminal member 12, 15: Fixing members 121: Upper surface of the fixing member 122: Through hole of fixing member 13, 16: Interrupting components (interrupting pins) 131: One end of the shut-off pin 132: Other end of the shut-off pin 14: Inside the gate (inside the gate) 150: Recessed hole in fixing member 151: Recessed portion of the fixing member 160: End of the shut-off pin 161: Protrusion of the shut-off pin 17: Spring component 20: Female interlock terminal 201: Tip of female interlock terminal 30: Male connector 31: Male connector terminal 32: Male connector housing 40: Female connector 41: Female connector terminal 42: Female connector housing 50: EV-CU 51: High-voltage battery 52: Inverter 53: Electric motor (motor generator)

Claims

1. An interlock mechanism used to detect whether an electrical connector is electrically connected or not, The male interlock terminal and the female interlock terminal are positioned in a location where their temperature rises due to the heat generated from the electrical connector. The aforementioned male interlock terminal comprises a terminal member, a fixing member fixed to the housing at both ends, and a blocking member that expands as the temperature rises. The tip of the terminal member is capable of contacting or separating from the female interlock terminal. The blocking member is located inside the terminal member, with one end supported by the fixing member and the other end in contact with the terminal member. An interlock mechanism with a fuse function, characterized in that the coefficient of linear expansion of the blocking member is set to be greater than the coefficient of linear expansion of the terminal member.

2. An interlock mechanism with a fuse function according to claim 1, An interlock mechanism with a fuse function, characterized in that a recessed hole is formed in the upper part of the fixing member, a recess is provided on the inner circumferential surface of the recessed hole, and a projection is provided on the outer surface of one end of the blocking member, and by fitting one end of the blocking member into the recessed hole of the fixing member, the recess and the projection are engaged, and when the length of the blocking member is extended, the engagement between the recess and the projection is released, and the projection rides up into the recessed hole, preventing the projection from returning to the recess.

3. An interlock mechanism with a fuse function according to claim 1 or 2, An interlock mechanism with a fuse function, characterized in that an elastic member is provided between the upper outer surface of the terminal member and the housing to press the terminal member toward the fixing member.

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