An electric vehicle DC-DC converter with isolation function

Abstract

The present invention relates to the technical field of DC-DC converters, and in particular, provides an electric vehicle DC-DC converter with an isolation function, comprising an aluminum alloy shell, a fixing plate provided at the bottom of the aluminum alloy shell, a DC-DC connector assembly provided on the aluminum alloy shell, the connector assembly comprising a DC-DC external connector fixed to the end of the aluminum alloy shell and an internal connector plugged into the external connector, a built-in interface is opened inward from the end of the aluminum alloy shell, the wiring terminals of the internal connector enter the built-in interface and plug with the wiring terminals in the built-in interface, and an elastic claw is provided at the bottom of the internal connector to quickly cut off the power of the external power supply and the components in the aluminum alloy shell, which is equivalent to quickly isolating the external power supply from the entire DC-DC converter. When the DC-DC converter is overheated during use, automatic power-off protection is achieved by quickly separating the internal connector from the external connector.

Description

Technical Field

[0001] The present invention relates to the technical field of electric vehicle accessories, and in particular to an electric vehicle DC-DC converter with an isolation function. Background Art

[0002] A DC-DC converter is a voltage converter that effectively outputs a fixed voltage after converting the input voltage. DC-DCDC converters are divided into three categories: boost DC / DC converters, buck DC / DC converters, and buck-boost DC / DC converters. For example, the DC-DC converter used in electric vehicles is a common power converter that converts one type of direct current into another type of direct current. For example, the patent application with application number CN201420398412.0 discloses an electric vehicle DC-DC isolation converter. It consists of an aluminum alloy body and an interface connected to one end of the aluminum alloy body, and a USB power plug is connected to the interface through a wire.

[0003] When the DC-DC converter is in use, the USB power plug is inserted into the power supply. When the power is connected and converted, a high conductive heat will be generated in the body. When the input current generated by the load overload exceeds the rated current of the internal components, a high heat will be generated in the body, which will not only affect the charging environment, but the large input current will also affect the service life of the internal components. Summary of the invention

[0004] In order to solve the above problems, the present invention provides an electric vehicle DC-DC converter with an isolation function, comprising an aluminum alloy shell, a fixing plate is provided at the bottom of the aluminum alloy shell, a fixing hole is provided on the fixing plate, a joint assembly is provided on the aluminum alloy shell, the joint assembly comprises an external joint fixed to the end of the aluminum alloy shell and an internal joint plugged into the external joint, a built-in interface is provided inwardly from the end of the aluminum alloy shell, a wiring terminal of the internal joint enters the built-in interface and is plugged with the wiring terminal in the built-in interface, an elastic claw is provided at the bottom of the internal joint, a card slot is provided at the bottom of the external joint, the elastic claw is downwardly inserted into the card slot so that the internal joint is fixed in the external joint, and a trigger located below the external joint is provided at the end of the aluminum alloy shell. The trigger mechanism comprises a trigger rod extending vertically upward, the top end of the trigger rod is pressed against the elastic claw, the trigger mechanism also comprises a trigger seat fixed at the end of the aluminum alloy shell, a trigger block is arranged in the trigger seat, the front end of the trigger block is provided with a downward inclined surface, the bottom end of the trigger rod penetrates into the trigger seat and is pressed against the inclined surface, an assembly cavity is opened inwardly from the end of the aluminum alloy shell, an elastic heat-conducting component is arranged in the assembly cavity, the elastic heat-conducting component comprises a threaded connection part at the front end and a fastening part at the rear end, a threaded hole is opened at the rear end of the trigger block, the threaded connection part at the front end of the elastic heat-conducting component is connected in the threaded hole, the fastening part at the rear end of the elastic heat-conducting component is tightly fixed in the assembly cavity, the fastening part is a rubber sleeve, and the fastening part is filled with an expansion agent.

[0005] As a further preference, the fastening portion is a rubber bellows, and the front end of the trigger block is slidably connected to the cavity wall of the assembly cavity.

[0006] As a further preferred embodiment, a stepped surface is provided in the middle portion of the inner joint, the diameter of the terminal of the inner joint is smaller than the diameter of the stepped surface, a spring is fused on the stepped surface, the spring is sleeved on the periphery of the terminal, the other end of the spring is connected to a protective sleeve sleeved on the periphery of the terminal, and the front end of the protective sleeve is pressed against the outer wall of the aluminum alloy shell.

[0007] As a further preference, an annular covering sleeve is provided at the front end of the protective sleeve, and the outer circumferential surface of the covering sleeve is in sliding contact with the inner cavity wall surface of the external joint.

[0008] As a further preferred embodiment, an air leakage hole is provided on the external joint, and the covering sleeve covers the air leakage hole by the inner cavity wall of the external joint, and when the covering sleeve slides forward, the air leakage hole leaks out, and the interior of the external joint communicates with the external gas of the external joint through the air leakage hole, and a chamfer is provided at the front end of the built-in interface, and the aperture of the built-in interface is larger than the diameter of the wiring terminal of the internal joint.

[0009] As a further preference, the root of the elastic claw is connected to the step surface, the trigger end of the elastic claw extends to the periphery of the spring, deviates outward from the periphery of the spring and extends into the slot of the external joint.

[0010] As a further preferred embodiment, a heat storage portion is provided inside the aluminum alloy shell, the heat storage portion is on the same side as the assembly cavity, a heat conducting portion is provided between the heat storage portion and the assembly cavity, a heat collecting portion with a trapezoidal surface structure is provided above the heat conducting portion, an integrated unit mounting plate is connected to the heat conducting portion, the integrated unit mounting plate extends flat to the other end inside the aluminum alloy shell, and all electrical components in the DC-DC converter are mounted on the integrated unit mounting plate.

[0011] As a further preferred embodiment, a guide seat is fixed on the top of the trigger seat, and a guide hole communicating with the trigger seat from top to bottom is opened between the guide seat and the trigger seat, the trigger rod passes through the guide hole, the bottom end of the trigger rod enters the trigger seat along the guide hole and contacts the inclined surface of the trigger block, and the top end of the trigger rod reaches the top of the guide seat along the guide hole, enters the card slot and presses against the bottom of the elastic claw.

[0012] Compared with the prior art, the present invention has the following beneficial effects:

[0013] When the components in the aluminum alloy housing generate high thermal current due to conduction or failure, the heat is released from the aluminum alloy housing into the assembly cavity. Since the space of the assembly cavity is relatively high, the heat will rise sharply in the assembly cavity. The high temperature heat is transferred to the fastening part through the assembly cavity, and the locking degree of the fastening part in the assembly cavity is reduced. At the same time, the fastening part releases the heat to the expansion agent. The expansion agent releases thrust forward when heated and pushes the threaded connection part forward. The threaded connection part pushes the trigger block forward, and the trigger block drives the inclined surface forward. The inclined surface moves along the bottom end of the trigger rod, and the trigger rod is pushed up by the inclined structure. The elastic claw is pushed by the top end of the trigger rod to withdraw the elastic claw from the slot. Back to the external connector, although the internal connector is inserted into the external connector at this time, and although the wiring terminal is still plugged into the wiring terminal in the built-in interface, the spring will release the elastic force, which acts on the internal connector from the front end and pushes the internal connector forward, and the internal connector drives the wiring terminal forward, so that the wiring terminal is separated from the wiring terminal in the built-in interface. The wiring terminal in the built-in interface is the power input terminal in the aluminum alloy shell. After the wiring terminal on the internal connector is separated from the wiring terminal in the built-in interface, it is equivalent to disconnecting the external power supply from the components in the aluminum alloy shell, and it is also equivalent to quickly disconnecting the external power supply from the DC-DC converter proposed by the present invention. When the converter is overheated during use, the converter can achieve automatic power-off protection by quickly separating the internal connector from the external connector. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 A schematic diagram of the assembly structure of a DC-DC converter for an electric vehicle with an isolation function provided by an embodiment of the present invention;

[0015] Figure 2 A schematic diagram of an internal connector of an electric vehicle DC-DC converter with an isolation function provided by an embodiment of the present invention being removed from an external connector;

[0016] Figure 3 A schematic top plan view of a DC-DC converter for an electric vehicle with an isolation function provided by an embodiment of the present invention;

[0017] Figure 4 An electric vehicle DC-DC converter with isolation function provided by the embodiment of the present invention is composed of Figure 3 The main plane diagram of the section A is shown below;

[0018] Figure 5 An electric vehicle DC-DC converter with isolation function provided by the embodiment of the present invention is composed of Figure 4 The introduced B section amplifies the intention;

[0019] Figure 6 An electric vehicle DC-DC converter with isolation function provided by the embodiment of the present invention is composed of Figure 4 The three-dimensional schematic diagram after the section is drawn;

[0020] Figure 7 An electric vehicle DC-DC converter with isolation function provided by the embodiment of the present invention is composed of Figure 1 Schematic diagram from an upward perspective.

[0021] In the figure: 1. aluminum alloy shell; 2. fixing plate; 3. fixing hole; 4. connector assembly; 5. external connector; 6. internal connector; 61. wiring terminal; 7. built-in interface; 8. elastic claw; 9. slot; 10. trigger mechanism; 11. trigger rod; 12. trigger seat; 13. trigger block; 14. inclined surface; 15. assembly cavity; 16. elastic heat conductive component; 17. threaded connection part; 18. fastening part; 19. threaded hole; 20. stepped surface; 21. spring; 22. protective cover; 23. heat storage part; 24. heat conductive part; 25. heat collecting part; 26. integrated unit mounting plate; 27. guide seat; 28. guide hole; 29. ​​cover cover; 30. vent hole; 31. chamfer. DETAILED DESCRIPTION

[0022] The above and other embodiments and advantages of the present invention are described clearly and completely below in conjunction with the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, not all embodiments.

[0023] In one embodiment, Figure 1-Figure 7 As shown:

[0024] The present embodiment provides an electric vehicle DC-DC converter with an isolation function, including an aluminum alloy shell 1, a fixing plate 2 is provided at the bottom of the aluminum alloy shell 1, a fixing hole 3 is provided on the fixing plate 2, a joint assembly 4 is provided on the aluminum alloy shell 1, the joint assembly 4 includes an external joint 5 fixed at the end of the aluminum alloy shell 1 and an internal joint 6 plugged into the external joint 5, a built-in interface 7 is provided inward from the end of the aluminum alloy shell 1, a wiring terminal 61 of the internal joint 6 enters the built-in interface 7 and is plugged into the wiring terminal in the built-in interface 7, an elastic claw 8 is provided at the bottom of the internal joint 6, a card slot 9 is provided at the bottom of the external joint 5, the elastic claw 8 is downwardly inserted into the card slot 9 so that the internal joint 6 is fixed in the external joint 5, and a trigger mechanism 10 located below the external joint 5 is provided at the end of the aluminum alloy shell 1, and the trigger mechanism 10 includes a vertical upward A trigger rod 11, the top of the trigger rod 11 is pressed against the elastic claw 8, the trigger mechanism 10 also includes a trigger seat 12 fixed to the end of the aluminum alloy shell 1, a trigger block 13 is arranged in the trigger seat 12, the front end of the trigger block 13 is provided with a downwardly inclined inclined surface 14, the bottom end of the trigger rod 11 penetrates into the trigger seat 12 and presses on the inclined surface 14, an assembly cavity 15 is opened inward from the end of the aluminum alloy shell 1, an elastic heat-conducting component 16 is arranged in the assembly cavity 15, the elastic heat-conducting component 16 includes a threaded connection portion 17 at the front end and a fastening portion 18 at the rear end, a threaded hole 19 is opened at the rear end of the trigger block 13, the threaded connection portion 17 at the front end of the elastic heat-conducting component 16 is connected in the threaded hole 19, the fastening portion 18 at the rear end of the elastic heat-conducting component 16 is tightly fixed in the assembly cavity 15, the fastening portion 18 is a rubber sleeve, and the fastening portion 18 is filled with an expansion agent.

[0025] The fastening portion 18 is a rubber bellows, and the front end of the trigger block 13 is slidably connected to the cavity wall of the assembly cavity 15 .

[0026] A stepped surface 20 is provided in the middle of the inner connector 6. The diameter of the terminal 61 of the inner connector 6 is smaller than the diameter of the stepped surface 20. A spring 21 is fused to the stepped surface 20. The spring 21 is sleeved on the periphery of the terminal. The other end of the spring 21 is connected to a protective sleeve 22 sleeved on the periphery of the terminal 61. The front end of the protective sleeve 22 is against the outer wall of the aluminum alloy housing 1.

[0027] An annular covering sleeve 29 is provided at the front end of the protective sleeve 22 , and the outer circumferential surface of the covering sleeve 29 is in sliding contact with the inner cavity wall surface of the external joint 5 .

[0028] The external connector 5 is provided with an air leakage hole 30, and the covering sleeve 29 covers the air leakage hole 30 by the inner cavity wall of the external connector 5. When the covering sleeve 29 slides forward, the air leakage hole 30 is exposed, and the inside of the external connector 5 is communicated with the external gas of the external connector 5 through the air leakage hole 30. The front end of the built-in interface 7 is provided with a chamfer 31, and the aperture of the built-in interface 7 is larger than the diameter of the terminal 61 of the internal connector 6.

[0029] The root of the elastic claw 8 is connected to the stepped surface 20 , and the trigger end of the elastic claw 8 extends to the periphery of the spring 21 , and deviates outward from the periphery of the spring 21 and then extends into the slot 9 of the external connector 5 .

[0030] A guide seat 27 is fixed to the top of the trigger seat 12, and a guide hole 28 communicating with the trigger seat 12 is opened between the guide seat 27 and the trigger seat 12. The trigger rod 11 passes through the guide hole 28, and the bottom end of the trigger rod 11 enters the trigger seat 12 along the guide hole 28 and contacts the inclined surface 14 of the trigger block 13. The top end of the trigger rod 11 reaches the top of the guide seat 27 along the guide hole 28, enters the card slot 9 and presses on the bottom of the elastic claw 8.

[0031] When the components in the aluminum alloy housing 1 generate high thermal current due to conduction or failure, the heat is released from the aluminum alloy housing 1 to the assembly cavity 15. Since the space of the assembly cavity 15 is small, the heat will rise sharply in a short time in the assembly cavity 15. The high temperature heat is released to the fastening part 18 at the rear end of the elastic heat-conducting component 16 through the assembly cavity 15, which will cause the locking degree of the fastening part 18 in the assembly cavity 15 to suddenly decrease. Since the fastening part 18 is filled with an expansion agent, the heat will also be released to the expansion agent, and the expansion agent will be heated and move forward. The thrust is released to push the threaded connection part 17 at the front end of the elastic heat-conducting component 16 forward, and the threaded connection part 17 pushes the trigger block 13 forward, and the trigger block 13 drives the inclined plane 14 forward. Since the bottom end of the trigger rod 11 falls on the inclined plane 14, when the inclined plane 14 moves forward, a thrust is formed on the bottom end of the trigger rod 11, forcing the trigger rod 11 to rise. When the trigger rod 11 rises, its top end pushes the top end of the trigger rod 11 to push the elastic claw 8, so that the elastic claw 8 is deflected upward from the card slot 9 and retreats into the tube cavity of the external joint 5. At this time, although the inner connector 6 is still inserted into the outer connector 5, and although the wiring terminal 61 on the inner connector 6 is still plugged into the wiring terminal in the built-in interface 7, since the elastic claw 8 is no longer restricted in the card slot 9 and no longer provides thrust to the spring 21 through the step surface 20, the spring 21 will release the elastic force forward and apply the ejection force to the step surface 20 in a forward ejection manner, and the step surface 20 acts on the inner connector 6, forcing the inner connector 6 to eject forward quickly, so that the wiring terminal 61 on the inner connector 6 is quickly separated from the wiring terminal in the built-in interface 7. Since the wiring terminal in the built-in interface 7 is the main electrical terminal that provides current to the aluminum alloy housing 1, and the inner connector 6 is the initial current that provides current to the wiring terminal in the built-in interface 7, after the wiring terminal 61 on the inner connector 6 is quickly separated from the wiring terminal in the built-in interface 7 in this way, it is equivalent to quickly powering off the external power supply and the components in the aluminum alloy housing 1, and it is also equivalent to quickly isolating the external power supply from the entire DC-DC converter. When the DC-DC converter becomes overheated during use, the internal connector 6 and the built-in interface 7 are quickly separated, thereby realizing automatic power-off protection of the DC-DC converter.

[0032] When the trigger rod 11 rises, the guide seat 27 plays a role of smooth guidance. In addition, the guide seat 27 can also accurately position the bottom end of the trigger rod 11 on the inclined surface 14 and the top end of the trigger rod 11 in the slot 9.

[0033] like Figure 4 , Figure 6As shown, a heat storage portion 23 is provided inside the aluminum alloy shell 1, and the heat storage portion 23 is on the same side as the assembly cavity 15. A heat conducting portion 24 is provided between the heat storage portion 23 and the assembly cavity 15. A heat collecting portion 25 with a trapezoidal surface structure is provided above the heat conducting portion 24. An integrated unit mounting plate 26 is connected to the heat conducting portion 24, and the integrated unit mounting plate 26 extends flat to the other end of the aluminum alloy shell 1. All electrical components in the DC-DC converter are mounted on the integrated unit mounting plate 26. The wiring terminals in the built-in interface 7 input current to each electrical component. Therefore, when the above-mentioned high heat phenomenon occurs due to factors such as circuit overload, the heat will be concentrated on the integrated unit mounting plate 26, and then concentrated from the integrated unit mounting plate 26 to the heat conducting portion 24. The heat conducting portion 24 is relatively thin, which further shortens the time for heat to be released to the fastening portion 18, so that the expansion agent in the fastening portion 18 expands rapidly, thereby improving the power-off efficiency of the wiring terminals in the inner joint 6 and the built-in interface 7.

[0034] like Figure 5 As shown, the front end of the protective sleeve 22 is provided with an annular covering sleeve 29, and the outer cylindrical surface of the covering sleeve 29 slides in contact with the inner cavity wall of the external joint 5. The rear end of the spring 21 is connected to the protective sleeve 22, and the spring 21 ejects the inner joint 6 forward. When the inner joint 6 moves forward, the inner joint 6 will also move forward with the spring 21, and the rear end of the spring 21 will move forward with the protective sleeve 22. The outer cylindrical surface of the protective sleeve 22 slides on the cavity wall of the external joint 5, ensuring that the inner joint 6 moves forward stably. The protective sleeve 22 also prevents the spring 21 from bending and deformation during its ejection action.

[0035] In addition, Figure 2 As shown, since an air leakage hole 30 is also provided on the covering sleeve 29, when the inner connector 6 is inserted into the outer connector 5 and used normally (when the wiring terminal 61 is normally connected to the wiring terminal in the built-in interface 7 and used), the covering sleeve 29 is close to the built-in interface 7, and the air leakage hole 30 is just covered by the outer circular surface, and the above-mentioned high temperature phenomenon occurs. When the spring 21 moves forward and pushes the inner connector 6 to move forward, the rear end of the spring 21 slides forward with the covering sleeve 29, and the covering sleeve 29 no longer covers the air leakage hole 30, and the high temperature heat in the built-in interface 7 is released synchronously.

[0036] The above orientation designations do not represent the specific orientations of the components in this implementation scheme. This implementation scheme is only for the convenience of describing the scheme, and the orientations are described relatively with reference to the figures. In essence, the specific orientations of the components are described according to their actual installation and actual use as well as the customary orientations of technicians in this field. This is hereby explained.

[0037] The specific implementation methods described above further describe the invention purpose, technical solutions, and beneficial effects of the present invention in detail. It should be understood that the above description is only a specific implementation method of the present invention and is not intended to limit the protection scope of the present invention. It is particularly pointed out that for those skilled in the art, any modifications, equivalent substitutions, improvements, etc. made within the spirit and principles of the present invention should be included in the protection scope of the present invention.

Claims

1. An electric vehicle DC-DC converter with isolation function, characterized in that: The invention comprises an aluminum alloy shell (1), a fixing plate (2) is provided at the bottom of the aluminum alloy shell (1), a fixing hole (3) is provided on the fixing plate (2), a joint assembly (4) is provided on the aluminum alloy shell (1), the joint assembly (4) comprises an external joint (5) fixed at the end of the aluminum alloy shell (1) and an internal joint (6) inserted into the external joint (5), a built-in interface (7) is provided inwardly from the end of the aluminum alloy shell (1), and a wiring terminal (61) of the internal joint (6) enters the built-in interface The inner connector (6) is plugged into the opening (7) and connected to the wiring terminal in the built-in interface (7); the bottom of the inner connector (6) is provided with an elastic claw (8); the bottom of the outer connector (5) is provided with a card slot (9); the elastic claw (8) is inserted downward into the card slot (9) so that the inner connector (6) is fixed in the outer connector (5); the end of the aluminum alloy housing (1) is provided with a trigger mechanism (10) located below the outer connector (5); the trigger mechanism (10) comprises a trigger rod (11) extending vertically upward; the trigger rod ( The top end of the trigger rod (11) is pressed against the elastic claw (8), the trigger mechanism (10) further comprises a trigger seat (12) fixed to the end of the aluminum alloy housing (1), a trigger block (13) is arranged in the trigger seat (12), a front end of the trigger block (13) is provided with a downwardly inclined inclined surface (14), the bottom end of the trigger rod (11) penetrates into the trigger seat (12) and presses against the inclined surface (14), an assembly cavity (15) is opened inward from the end of the aluminum alloy housing (1), and a There is an elastic heat-conducting component (16), the elastic heat-conducting component (16) comprising a threaded connection portion (17) at the front end and a fastening portion (18) at the rear end, the rear end of the trigger block (13) is provided with a threaded hole (19), the threaded connection portion (17) at the front end of the elastic heat-conducting component (16) is connected to the threaded hole (19), the fastening portion (18) at the rear end of the elastic heat-conducting component (16) is tightly fixed in the assembly cavity (15), the fastening portion (18) is a rubber sleeve, and the fastening portion (18) is filled with an expansion agent.

2. The electric vehicle DC-DC converter with isolation function according to claim 1, characterized in that: The fastening portion (18) is a rubber bellows, and the front end of the trigger block (13) is slidably connected to the cavity wall of the assembly cavity (15).

3. The electric vehicle DC-DC converter with isolation function according to claim 2, characterized in that: A stepped surface (20) is provided in the middle of the inner joint (6); the diameter of the connecting terminal (61) of the inner joint (6) is smaller than the diameter of the stepped surface (20); a spring (21) is fused to the stepped surface (20); the spring (21) is sleeved on the periphery of the connecting terminal; the other end of the spring (21) is connected to a protective sleeve (22) sleeved on the periphery of the connecting terminal (61); the front end of the protective sleeve (22) is pressed against the outer wall of the aluminum alloy housing (1).

4. The electric vehicle DC-DC converter with isolation function according to claim 3, characterized in that: An annular covering sleeve (29) is provided at the front end of the protective sleeve (22), and the outer circumferential surface of the covering sleeve (29) is in sliding contact with the inner cavity wall surface of the external joint (5).

5. The electric vehicle DC-DC converter with isolation function according to claim 4, characterized in that: The external joint (5) is provided with an air leakage hole (30), and the covering sleeve (29) covers the air leakage hole (30) through the inner cavity wall of the external joint (5). When the covering sleeve (29) slides forward, the air leakage hole (30) is leaked, and the interior of the external joint (5) is connected to the external gas of the external joint (5) through the air leakage hole (30). The front end of the internal interface (7) is provided with a chamfer (31), and the hole diameter of the internal interface (7) is larger than the diameter of the connection terminal (61) of the internal joint (6).

6. The electric vehicle DC-DC converter with isolation function according to claim 5, characterized in that: The root of the elastic claw (8) is connected to the stepped surface (20), and the trigger end of the elastic claw (8) extends toward the periphery of the spring (21), deviates outward from the periphery of the spring (21), and then extends into the slot (9) of the external joint (5).

7. The electric vehicle DC-DC converter with isolation function according to claim 6, characterized in that: A heat storage portion (23) is provided inside the aluminum alloy housing (1), the heat storage portion (23) and the assembly cavity (15) are on the same side, a heat conducting portion (24) is provided between the heat storage portion (23) and the assembly cavity (15), a heat collecting portion (25) with a trapezoidal surface structure is provided above the heat conducting portion (24), an integrated unit mounting plate (26) is connected to the heat conducting portion (24), the integrated unit mounting plate (26) extends flat to the other end inside the aluminum alloy housing (1), and all electrical components in the DC-DC converter are mounted on the integrated unit mounting plate (26).

8. The electric vehicle DC-DC converter with isolation function according to claim 7, characterized in that: A guide seat (27) is fixed on the top of the trigger seat (12); a guide hole (28) communicating with the trigger seat (12) is provided between the guide seat (27) and the trigger seat (12); the trigger rod (11) passes through the guide hole (28); the bottom end of the trigger rod (11) enters the trigger seat (12) along the guide hole (28) and contacts the inclined surface (14) of the trigger block (13); the top end of the trigger rod (11) reaches the top of the guide seat (27) along the guide hole (28), enters the clamping groove (9) and presses against the bottom of the elastic claw (8).

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