A high voltage DC thermal fuse

Abstract

The present invention belongs to the technical field of temperature fuses, and in particular relates to a high-voltage DC temperature fuse, comprising: a housing, an internal sliding sleeve of the housing is provided with a connecting sleeve, the ends of the housing and the connecting sleeve that are away from each other are fixedly connected to a first conductor and a second conductor respectively, a movable cavity is opened at the center of the connecting sleeve, a temperature sensor is provided in the movable cavity, and the two ends of the temperature sensor are in contact with the first conductor and the second conductor respectively. The present invention provides an automatic ejection mechanism and utilizes the synergistic effect of thermal expansion and contraction liquid and hydraulic oil. When the temperature of the temperature sensor rises slightly, the thermal expansion and contraction liquid will expand rapidly, pushing the first piston ring and the second piston ring to move, thereby quickly triggering a series of subsequent actions, pushing the temperature sensor out and cutting off the circuit. It can respond quickly to a wider range of over-temperature conditions, greatly shorten the time difference of over-temperature protection, and more comprehensively protect various components in the circuit.

Description

Technical Field

[0001] The invention belongs to the technical field of temperature fuses, and in particular relates to a high-voltage direct current temperature fuse. Background Art

[0002] In today's power sector, with the increasing adoption of high-voltage DC (HVDC) systems, the requirements for their safety and stability are becoming increasingly stringent. As a key component for circuit safety, HVDC thermal fuses play a vital role in numerous scenarios, such as battery management systems for new energy vehicles, HVDC transmission lines, and power modules for industrial automation equipment.

[0003] A search revealed that patent document CN220491824U discloses a high-voltage DC thermal fuse, comprising a first spring, a spacer, a first conductor, a first temperature sensor, a conductive connector, and a second conductor. The first conductor and the second conductor are connected via the first temperature sensor and the conductive connector to form two conductive paths. When the first temperature sensor melts and its volume decreases or is incompletely melted due to temperature increase, the fuse pushes the spacer through the first spring to quickly cut off the path between the first temperature sensor and the conductive connector, isolating the two originally connected conductors and thus cutting off their path. This ensures that the entire circuit can be completely disconnected even when the current is low, effectively protecting the circuit safety.

[0004] However, the above-mentioned fuse still has the following technical problems during use:

[0005] First, its automatic cutoff mechanism relies primarily on the push of the first spring after the temperature sensor melts. If the temperature sensor heats up rapidly but hasn't yet melted, it can't react in time. This creates a delay in overtemperature protection, potentially causing damage to other components in the circuit due to overheating during this brief delay.

[0006] Secondly, the connection structure of the fuse is relatively simple. When faced with complex working environments, such as severe vibration and large temperature fluctuations, the connection sleeve and the shell are prone to loosening. Once loose, it may affect the contact between the temperature sensor and the conductor, thereby interfering with the stability of current transmission and even causing safety hazards such as false connection and sparking.

[0007] Third, the fuse lacks a feedback mechanism for its own status. Users cannot intuitively understand whether the fuse is working properly, or cannot promptly know when an abnormality occurs, which is not conducive to timely maintenance and replacement. Users may continue to use an expired fuse without knowing it, posing potential risks to the entire circuit system. Summary of the Invention

[0008] The purpose of the present invention is to address the problems raised in the above background technology and provide a high-voltage DC thermal fuse that can quickly respond to a wider range of over-temperature conditions, greatly shorten the time difference of over-temperature protection, and more comprehensively protect various components in the circuit.

[0009] In order to achieve the above object, the present invention adopts the following technical solutions:

[0010] A high-voltage DC thermal fuse, comprising:

[0011] A housing, wherein the internal sliding sleeve of the housing is provided with a connecting sleeve, and ends of the housing and the connecting sleeve that are away from each other are fixedly connected to a first conductor and a second conductor respectively, a movable cavity is opened at the center of the connecting sleeve, and a temperature sensor is provided in the movable cavity, and two ends of the temperature sensor are in contact with the first conductor and the second conductor respectively;

[0012] An automatic locking mechanism for automatically locking the connecting sleeve after it is inserted into the housing, the automatic locking mechanism comprising two symmetrically distributed slide grooves formed on the outer wall of the connecting sleeve, a wedge-shaped block slidably connected within the slide grooves, a slot for cooperating with the wedge-shaped block formed on the side wall of the housing, and a first spring fixedly connected between the wedge-shaped block and the inner wall of the slide groove;

[0013] The automatic ejection mechanism is used to automatically eject the temperature sensor from the active cavity when the temperature of the temperature sensor is too high.

[0014] Preferably, the automatic ejection mechanism includes a first annular cavity provided inside the circumferential side wall of the connecting sleeve, a first piston ring and a second piston ring are sealingly and slidably connected inside the first annular cavity, a heat-conducting rod is fixedly connected to the inner wall of the connecting sleeve, two ends of the heat-conducting rod extend into the first annular cavity and the movable cavity respectively, one end of the heat-conducting rod is located between the first piston ring and the second piston ring, and the other end slides in contact with the temperature sensing body, a second annular cavity is provided inside the circumferential side wall of the connecting sleeve, a third piston ring is sealingly and slidably connected in the second annular cavity, a push rod is fixedly connected between the third piston ring and the second piston ring, a plurality of second springs distributed in a circumferential array are fixedly connected between the third piston ring and the inner wall of the second annular cavity, a push block is fixedly connected to the circumferential side wall of the temperature sensing body, the push block is sealingly and slidably connected to the inner wall of the movable cavity, and a first communicating groove is provided between the second annular cavity and the movable cavity.

[0015] Preferably, a first liquid storage space is formed between the first piston ring and the second piston ring, and the first liquid storage space is filled with thermal expansion and contraction liquid.

[0016] Preferably, a second liquid storage space is formed among the third piston ring, the second annular cavity, the first communicating groove, the movable cavity and the push block, and the second liquid storage space is filled with hydraulic oil.

[0017] Preferably, a control groove is provided on one side wall of the first annular cavity close to the slide groove, a piston block is sealingly and slidingly connected in the control groove, a connecting rod is fixedly connected between the piston block and the wedge-shaped block, and a second connecting groove is provided between the control groove and the first annular cavity.

[0018] Preferably, a limiting groove is provided inside the peripheral side wall of the connecting sleeve, and the connecting rod is slidably connected to the limiting groove.

[0019] Preferably, a third liquid storage space is formed among the first piston ring, the first annular cavity, the second communicating groove, the control groove and the piston block, and the third liquid storage space is filled with hydraulic oil.

[0020] Preferably, the elastic coefficient of the second spring is greater than the elastic coefficient of the first spring.

[0021] Compared with existing technologies, the advantages of this high-voltage DC thermal fuse are:

[0022] 1. This invention incorporates an automatic ejection mechanism, leveraging the synergistic effects of thermal expansion and contraction fluid and hydraulic oil. When the temperature of the temperature sensor rises slightly, the thermal expansion and contraction fluid rapidly expands, pushing the first and second piston rings to move. This rapidly triggers a series of subsequent actions, ejecting the temperature sensor and disconnecting the circuit. Compared to traditional fuses that rely on melting the temperature sensor, this fuse can respond quickly to a wider range of overtemperature conditions, significantly shortening the time lag for overtemperature protection, more comprehensively protecting various components in the circuit, and effectively reducing the risk of component damage due to overheating.

[0023] 2. The present invention is provided with an automatic locking mechanism, which can automatically lock after the connecting sleeve is inserted into the interior of the shell. The wedge-shaped clamping block is tightly clamped into the slot under the action of the first spring, and with the reasonable structural design, the connection between the connecting sleeve and the shell is very stable. Even in complex environments such as vibration and large temperature changes, it can ensure that the connecting sleeve and the shell do not loosen, maintain a good contact state between the temperature sensor and the first conductor and the second conductor, ensure stable current transmission, avoid safety problems such as false connection and sparking caused by loose connection, and significantly improve the reliability of the fuse in complex working environments.

[0024] 3. The present invention utilizes an automatic ejection mechanism in conjunction with an automatic locking mechanism, so that when the temperature sensor is ejected due to overheating, the automatic locking mechanism is unlocked. This structural change provides the user with intuitive feedback on the fuse status. When the connecting sleeve and the housing are no longer locked, it can be determined that the fuse has triggered the protection mechanism due to overheating and needs to be replaced. This facilitates the user's maintenance and management of the fuse, allowing for the timely replacement of failed fuses to ensure the continued stable operation of the entire circuit system. BRIEF DESCRIPTION OF THE DRAWINGS

[0025] Figure 1 This is a schematic diagram of the three-dimensional structure of a high-voltage DC thermal fuse provided by the present invention;

[0026] Figure 2 This is a schematic cross-sectional view of a high-voltage DC thermal fuse provided by the present invention;

[0027] Figure 3 This is a schematic diagram of the cross-sectional structure of a disassembled high-voltage DC thermal fuse provided by the present invention;

[0028] Figure 4 yes Figure 2 Enlarged view of point A in the middle;

[0029] Figure 5 yes Figure 2 Enlarged view of point B in the middle.

[0030] In the picture:

[0031] 1. Housing; 11. Connecting sleeve; 12. First conductor; 13. Second conductor; 14. Active cavity; 15. Temperature sensor; 2. Automatic locking mechanism; 21. Slide groove; 22. Wedge-shaped block; 23. Slot; 24. First spring; 3. Automatic ejection mechanism; 31. First annular cavity; 32. First piston ring; 33. Second piston ring; 34. Heat-conducting rod; 35. Second annular cavity; 36. Third piston ring; 37. Push rod; 38. Second spring; 39. Push block; 310. First connecting groove; 4. Control groove; 41. Piston block; 42. Connecting rod; 43. Second connecting groove; 5. Limiting groove. DETAILED DESCRIPTION

[0032] The following examples are for illustrative purposes only and are not intended to limit the scope of the present invention.

[0033] Example: Refer to Figures 1 to 5 , a high voltage DC thermal fuse, comprising:

[0034] The shell 1 has an internal sliding sleeve provided with a connecting sleeve 11. The shell 1 and the connecting sleeve 11 are fixedly connected at one end away from each other with a first conductor 12 and a second conductor 13. These two conductors serve to connect the external circuit so that the current can pass through the fuse smoothly. The center of the connecting sleeve 11 is provided with an active cavity 14, which provides a movable space for a temperature sensor 15. The temperature sensor 15 is provided in the active cavity 14. The temperature sensor 15 is a key component of the fuse and is used to sense temperature changes. The two ends of the temperature sensor 15 are in contact with the first conductor 12 and the second conductor 13 respectively, thereby forming a conductive path under normal circumstances to ensure the transmission of current.

[0035] The first spring 24 is fixedly connected between the wedge block 22 and the inner wall of the slide groove 21, and the first spring 24 provides elastic force, so that the wedge block 22 always maintains the tendency to move in the direction of the slot 23 to maintain the locked state.

[0036] The automatic ejection mechanism 3 is used to automatically eject the temperature sensing body 15 from the active cavity 14 when the temperature of the temperature sensing body 15 is too high. The automatic ejection mechanism 3 includes a first annular cavity 31 formed inside the side wall of the connecting sleeve 11. The first annular cavity 31 provides a movable space for the first piston ring 32 and the second piston ring 33. The first annular cavity 31 is sealed and slidably connected with the first piston ring 32 and the second piston ring 33. They can slide in the first annular cavity under the action of the thermal expansion and contraction liquid. A heat-conducting rod 34 is fixedly connected to the inner wall of the connecting sleeve 11. The heat-conducting rod 34 plays the role of heat conduction and can transfer the heat of the temperature sensing body 15 to the inner wall of the connecting sleeve 11. The heat conducting rod 34 is passed to the first annular cavity, and both ends of the heat conducting rod 34 extend into the first annular cavity 31 and the movable cavity 14 respectively. One end of the heat conducting rod 34 is located between the first piston ring 32 and the second piston ring 33, and the other end is in sliding contact with the temperature sensing body 15. In this way, when the temperature of the temperature sensing body 15 rises, the heat can be quickly transferred to the heat conducting rod 34. A second annular cavity 35 is opened inside the side wall of the connecting sleeve 11. The second annular cavity 35 provides a movable space for the third piston ring 36. The third piston ring 36 is sealed and slidably connected in the second annular cavity 35. The third piston ring 36 pushes the push rod 37 to move under the action of hydraulic oil. A push rod 37 is fixedly connected between the third piston ring 36 and the second piston ring 33 for transmitting the movement of the piston. A plurality of second springs 38 distributed in a circumferential array are fixedly connected between the third piston ring 36 and the inner wall of the second annular cavity 35. The second spring 38 plays a reset role to keep the position of the third piston ring 36 stable when the temperature sensing body 15 is not overheated. A push block 39 is fixedly connected to the peripheral side wall of the temperature sensing body 15. The push block 39 is used to push the temperature sensing body 15 to move. The push block 39 is sealingly and slidably connected to the inner wall of the active cavity 14, which can not only ensure the stable movement of the temperature sensing body 15, but also prevent liquid leakage. A first connecting groove 310 is provided between the second annular cavity 35 and the active cavity 14 to enable the hydraulic oil in the second annular cavity 35 and the active cavity 14 to circulate, thereby realizing force transmission.

[0037] Specifically, a first liquid storage space is formed between the first piston ring 32 and the second piston ring 33, and the first liquid storage space is filled with thermal expansion and contraction liquid. When the temperature of the temperature sensing body 15 rises, the thermal expansion and contraction liquid expands due to heat and pushes the first piston ring 32 and the second piston ring 33 to move, thereby triggering a subsequent ejection action.

[0038] Specifically, a second liquid storage space is formed between the third piston ring 36, the second annular cavity 35, the first connecting groove 310, the movable cavity 14 and the push block 39, and the second liquid storage space is filled with hydraulic oil. The hydraulic oil plays a role in transmitting pressure, transmitting the movement of the third piston ring 36 to the push block 39, thereby pushing the temperature sensing body 15.

[0039] A control groove 4 is provided on one side wall of the first annular cavity 31 close to the slide groove 21. The control groove 4 is used to accommodate the piston block 41 and limit its movement direction. The piston block 41 is sealed and slidably connected in the control groove 4. The piston block 41 moves under the action of hydraulic oil. A connecting rod 42 is fixedly connected between the piston block 41 and the wedge-shaped block 22. The connecting rod 42 is used to transmit the movement of the piston block 41 so that the wedge-shaped block 22 can move driven by the piston block 41. A second connecting groove 43 is provided between the control groove 4 and the first annular cavity 31. The second connecting groove 43 allows the hydraulic oil in the first annular cavity 31 to flow into the control groove 4, thereby pushing the piston block 41 to move.

[0040] Specifically, a limiting groove 5 is opened inside the peripheral side wall of the connecting sleeve 11, and the connecting rod 42 is slidably connected to the limiting groove 5. The limiting groove 5 limits the connecting rod 42, ensuring that the connecting rod 42 can only slide in the specified direction, thereby ensuring the movement accuracy of the wedge-shaped block 22.

[0041] Specifically, a third liquid storage space is formed between the first piston ring 32, the first annular cavity 31, the second connecting groove 43, the control groove 4 and the piston block 41, and the third liquid storage space is filled with hydraulic oil. The hydraulic oil transmits pressure in this space, so that the movement of the first piston ring 32 can be transmitted to the piston block 41 through the hydraulic oil, thereby controlling the action of the wedge-shaped clamping block 22.

[0042] Specifically, the elastic coefficient of the second spring 38 is greater than the elastic coefficient of the first spring 24. Under normal circumstances, the first spring 24 can maintain the locked state of the wedge block 22. When the temperature of the temperature sensing body 15 is too high, the expansion of the thermal expansion and contraction fluid first overcomes the elastic force of the first spring 24, so that the piston block 41 can drive the wedge block 22 to move through the connecting rod 42, so that the wedge block 22 no longer locks the shell 1 and the connecting sleeve 11. After the connecting sleeve 11 is pulled out of the shell 1, the expansion of the thermal expansion and contraction fluid overcomes the elastic force of the second spring 38, so that the automatic ejection mechanism 3 can operate smoothly, push the temperature sensing body 15 out of the active cavity 14, cut off the circuit, and achieve over-temperature protection.

[0043] The functional principle of the present invention can be explained through the following operation: Under normal operating conditions, the temperature sensor 15 is located within the active cavity 14, with its ends in contact with the first conductor 12 and the second conductor 13, forming a conductive path, allowing current to flow normally through the fuse. If an abnormality occurs in the circuit, causing the temperature of the temperature sensor 15 to rise, the heat from the temperature sensor 15 is transferred to the thermal expansion and contraction fluid in the first liquid storage space via the heat conducting rod 34. The thermal expansion and contraction liquid expands due to heat, pushing the first piston ring 32 and the second piston ring 33 to move successively. The hydraulic oil in the first liquid storage space flows into the control groove 4 through the second connecting groove 43, pushing the piston block 41. The piston block 41 drives the wedge block 22 through the connecting rod 42 to overcome the elastic force of the first spring 24 and slide into the slide groove 21, so that the wedge block 22 disengages from the groove 23, releasing the lock of the automatic locking mechanism 2. At the same time, the second piston ring 33 pushes the third piston ring 36 to move in the second annular cavity 35 through the push rod 37, compressing the second spring 38. The hydraulic oil in the second liquid storage space enters the active cavity 14 through the first connecting groove 310, pushing the push block 39, and then pushing the temperature sensing body 15 out of the active cavity 14, cutting off the conductive path between the first conductor 12 and the second conductor 13, thereby realizing over-temperature protection of the circuit.

[0044] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the scope of protection of the present invention.

Claims

1. A high voltage DC thermal fuse, characterized in that: include: A housing (1), wherein an internal sliding sleeve of the housing (1) is provided with a connecting sleeve (11), and ends of the housing (1) and the connecting sleeve (11) that are away from each other are fixedly connected to a first conductor (12) and a second conductor (13), respectively; a movable cavity (14) is provided at the center of the connecting sleeve (11), a temperature sensing body (15) is provided in the movable cavity (14), and two ends of the temperature sensing body (15) are in contact with the first conductor (12) and the second conductor (13), respectively; An automatic locking mechanism (2) is used for automatically locking the connecting sleeve (11) after it is inserted into the housing (1), the automatic locking mechanism (2) comprising two symmetrically distributed slide grooves (21) provided on the outer wall of the connecting sleeve (11), a wedge-shaped clamping block (22) being slidably connected in the slide groove (21), a clamping groove (23) for use with the wedge-shaped clamping block (22) being provided on the side wall of the housing (1), and a first spring (24) being fixedly connected between the wedge-shaped clamping block (22) and the inner wall of the slide groove (21); An automatic ejection mechanism (3) for automatically ejecting the temperature sensing body (15) from the active cavity (14) when the temperature of the temperature sensing body (15) is too high; The automatic ejection mechanism (3) includes a first annular cavity (31) provided inside the peripheral side wall of the connecting sleeve (11), a first piston ring (32) and a second piston ring (33) are sealed and slidably connected inside the first annular cavity (31), a heat-conducting rod (34) is fixedly connected to the inner wall of the connecting sleeve (11), and two ends of the heat-conducting rod (34) extend into the first annular cavity (31) and the movable cavity (14), respectively, one end of the heat-conducting rod (34) is located between the first piston ring (32) and the second piston ring (33), and the other end is in sliding contact with the temperature sensing body (15), and the inner side wall of the connecting sleeve (11) is provided with a heat-conducting rod (34). A second annular cavity (35) is provided, a third piston ring (36) is sealingly and slidably connected in the second annular cavity (35), a push rod (37) is fixedly connected between the third piston ring (36) and the second piston ring (33), a plurality of second springs (38) distributed in a circumferential array are fixedly connected between the third piston ring (36) and the inner wall of the second annular cavity (35), a push block (39) is fixedly connected to the circumferential side wall of the temperature sensing body (15), the push block (39) is sealingly and slidably connected to the inner wall of the active cavity (14), and a first connecting groove (310) is provided between the second annular cavity (35) and the active cavity (14); A first liquid storage space is formed between the first piston ring (32) and the second piston ring (33), and the first liquid storage space is filled with a thermal expansion and contraction liquid; A control groove (4) is provided on a side wall of the first annular cavity (31) close to the slide groove (21), a piston block (41) is sealingly and slidably connected in the control groove (4), a connecting rod (42) is fixedly connected between the piston block (41) and the wedge-shaped clamping block (22), and a second connecting groove (43) is provided between the control groove (4) and the first annular cavity (31).

2. The high-voltage DC thermal fuse according to claim 1, characterized in that: A second liquid storage space is formed between the third piston ring (36), the second annular cavity (35), the first communicating groove (310), the movable cavity (14) and the push block (39), and the second liquid storage space is filled with hydraulic oil.

3. The high-voltage DC thermal fuse according to claim 1, characterized in that: A limiting groove (5) is provided inside the peripheral side wall of the connecting sleeve (11), and the connecting rod (42) is slidably connected to the limiting groove (5).

4. The high-voltage DC thermal fuse according to claim 1, characterized in that: A third liquid storage space is formed between the first piston ring (32), the first annular cavity (31), the second communicating groove (43), the control groove (4) and the piston block (41), and the third liquid storage space is filled with hydraulic oil.

5. The high-voltage DC thermal fuse according to claim 4, characterized in that: The elastic coefficient of the second spring (38) is greater than the elastic coefficient of the first spring (24).

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