A draw-out low voltage switchgear

Abstract

The application relates to the field of power distribution cabinet equipment, in particular to a pull-out type low-voltage switch cabinet which comprises a cabinet body and an air duct, the air duct is fixed vertically in the interior of the cabinet body, a plurality of groups of drawers are arranged vertically and in a stacked manner in the interior of the cabinet body in front of the air duct, a bracket for supporting the front and back sliding of the drawers is arranged on the inner side of the cabinet body, a self-sealing assembly corresponding to the drawers is communicated with the front side of the air duct, and an air inlet assembly is penetrated through the inner side of the drawer and connected to the front port of the self-sealing assembly. An air duct automatic closing mechanism is arranged, the air outlet of the air duct can be automatically opened and closed when the drawers are in the in-place state and the pulled-out state, the overall air duct air pressure is prevented from being insufficient and the electrical element is prevented from being overheated after a single drawer is pulled out; the circuit closing, drawer locking and air duct conduction are integrated, the handle rotation synchronously realizes the circuit breaker closing conduction loop, the lock rod descending locking drawer and the air inlet assembly rotating conduction cooling air duct, and the reset handle can synchronously realize the loop opening, the drawer unlocking and the air duct automatic closing, so that the operation and maintenance steps are simplified.

Description

Technical Field

[0001] This invention relates to the field of power distribution cabinet equipment, and more specifically to a withdrawable low-voltage switchgear. Background Technology

[0002] Low-voltage withdrawable switchgear, as the core equipment for power distribution, circuit protection, and electrical control in power distribution systems, is widely used in factory power distribution, commercial buildings, municipal power, rail transit, and other scenarios. Traditional withdrawable low-voltage switchgear uses layered, pull-out functional drawers within the cabinet to achieve independent installation, maintenance, and replacement of electrical units in each circuit. It has the advantages of convenient operation and maintenance and high power supply reliability, making it the mainstream equipment in the field of low-voltage complete power distribution systems.

[0003] Currently, conventional switchgear often uses a fixed, normally open connection structure between the vertical air ducts and each drawer. When the drawers are pulled out for maintenance, the air vents of the air ducts are directly exposed and open. On the one hand, the cooling airflow inside the cabinet will leak out in large quantities from the empty air vents, resulting in insufficient heat dissipation air pressure. The heat dissipation efficiency of the remaining drawers will decrease significantly, which can easily lead to safety hazards such as overheating and tripping of electrical components and accelerated insulation aging. On the other hand, the open air vents will allow dust, moisture, and debris to enter the cabinet through the air ducts and adhere to the surfaces of precision electrical components such as busbars, terminals, and circuit breakers. Long-term accumulation can easily cause electrical faults such as short circuits, poor contact, and insulation breakdown.

[0004] Furthermore, traditional drawers rely solely on slide rails for front and rear positioning after being pushed into the cabinet. Lacking a pre-positioning and anti-detachment structure during the pushing process, the drawer is prone to slipping off the front end of the slide rail when being pushed in or fine-tuning the installation position, causing damage to the primary plug-in terminals and deformation of the air duct connection structure. At the same time, the air duct plug-in part lacks a locking and limiting structure, and under vibration conditions, the air duct connection is prone to circumferential displacement and axial loosening, resulting in air leakage in the cooling air duct and failure of unit heat dissipation, which seriously restricts the long-term stable operation of the switch cabinet. Summary of the Invention

[0005] The purpose of this invention is to provide a withdrawable low-voltage switchgear to solve the above-mentioned problems. By setting an automatic duct closing mechanism, the air outlet of the duct can be automatically opened and closed when the drawer is in place or withdrawn, avoiding insufficient air pressure in the overall duct and overheating of electrical components after a single drawer is withdrawn. The circuit closing, drawer locking, and duct opening are integrated into one unit. The rotation of the handle synchronously realizes the circuit breaker closing and conduction of the circuit, the lowering of the locking rod to lock the drawer, and the rotation of the air intake component to conduct the cooling air duct. Resetting the handle synchronously realizes the circuit opening, drawer unlocking, and automatic duct closing, simplifying the operation and maintenance steps, as detailed below.

[0006] To achieve the above objectives, the present invention provides the following technical solution: The present invention provides a withdrawable low-voltage switchgear, including a cabinet and an air duct. The air duct is vertically fixed inside the cabinet. Several sets of drawers are vertically stacked inside the cabinet in front of the air duct. The cabinet is provided with brackets that support the front and rear sliding of the drawers. A self-sealing component corresponding to the drawer is provided on the front side of the air duct. An air inlet component that can be inserted and cooperated with the self-sealing component is provided on the rear side of the drawer. The self-sealing component is provided with a normally closed closing mechanism. When the air inlet component is inserted into the position, it can drive the closing mechanism to open, so as to guide the air duct and the airflow passage inside the drawer. The drawer is equipped with an operating component, which can drive the locking mechanism between the drawer and the bracket to operate, and simultaneously drive the air inlet component and the self-sealing component to form a locking engagement. When the drawer detaches from the self-sealing component, the closing mechanism automatically resets and seals the air duct.

[0007] Preferably, the self-sealing assembly includes a self-sealing tube connected to a ventilation duct. A conical ring is fixed inside the self-sealing tube, and a support ring is fixed inside the tail end of the self-sealing tube. A closing rod extends longitudinally through the inner side of the support ring. A conical disc that fits against the closing conical ring is fixed to the front side of the closing rod. A spring is sleeved on the outer side of the closing rod to keep the conical disc pressed against the surface of the conical ring. The spring, together with the conical disc and the conical ring, forms a closing mechanism. The air inlet assembly includes an air distribution pipe sleeved outside the self-sealing tube. A push rod is provided inside the air distribution pipe to push the conical disc away from the conical ring, thereby opening the closing mechanism inside the self-sealing tube when the air inlet assembly is inserted into the outside of the self-sealing assembly.

[0008] When using the above-mentioned withdrawable low-voltage switchgear, if the drawer and its internal electrical components need to be inserted into the set position bracket inside the cabinet, the tail section of the drawer is placed into the top side of the bracket and pushed backward until the tail end of the air distribution pipe of the air inlet component on the rear side of the drawer is inserted into the outside of the self-sealing pipe of the self-sealing component. At this time, the connection terminal of the drawer is connected to the fixed terminal of the cabinet. During the process of inserting the tail end of the air inlet assembly into the front end of the self-sealing assembly, the locking piece of the air distribution tube and the clamping piece of the self-sealing tube are in an interlocked state. That is, the front end of the self-sealing tube allows the tail end of the air distribution tube to be inserted and engaged. At this time, the air distribution tube is sleeved around the outside of the self-sealing tube. As the convex edge of the air distribution tube moves backward, it expands outward to support the clamping piece. Under the action of the torsion spring, the clamping piece is clamped to the outer wall of the air distribution tube. The convex edge engages with the clamping piece to restrict the air distribution tube from moving forward and backward, thereby pre-positioning the entire drawer and preventing the drawer from slipping out. At the same time, the movable teeth of the force ring at the front end of the push rod move backward to the fixed teeth position of the meshing cone, and the force ring and the cone fit tightly together, keeping the rear self-sealing component in a closed state; When the handle needs to be rotated to activate the internal circuit of the drawer, the operating shaft at the rear end of the handle is connected to the circuit breaker switch. Rotating the handle rotates the operating shaft, causing the circuit breaker to close and activating the internal circuit of the drawer. At the same time, the support arm connected to the outer end of the operating shaft drives the eccentric shaft to rotate downward. The eccentric shaft drives the transmission frame to move the locking rod downward. The locking rod passes down through the upper locking hole into the lower locking hole, thereby locking the entire drawer onto the bracket and completing the mechanical locking of the front and rear positions of the drawer. While the drawer is locked, the operating shaft drives the transmission end cover of the air intake assembly to rotate via the synchronous belt. The transmission end cover drives the entire air intake assembly to rotate. The air duct of the air intake assembly rotates to the position where the external locking piece and the clamping piece of the self-sealing tube coincide. The wedge-shaped claw of the clamping piece locks and closes with the matching locking piece, locking the front and rear positions of the air duct and achieving secondary locking of the drawer position. During the rotation and locking process of the air intake assembly, the force ring drives the movable teeth to rotate synchronously. The movable teeth of the helical tooth structure push the fixed teeth of the self-sealing assembly outward, thereby pushing the fixed teeth and the cone plate away from the cone ring, thus separating the cone plate and the cone ring to open the air intake channel. At the same time, the spring is compressed and stored to automatically close the air intake channel when the drawer is pulled out. The air duct is connected to an external cooling fan. The airflow enters the air distribution duct along several sets of self-sealing components. After being filtered and collected by the dust filter sleeve inside the air distribution duct, the gas is discharged into the corresponding drawer along the air distribution duct, forming a positive pressure airflow in the drawer for heat dissipation. When removing the drawer, rotate the handle to reset it, the locking rod moves upward, and the air duct reverses. The moving teeth and fixed teeth engage again, the conical disc and conical ring automatically close the self-sealing tube cavity, and the locking piece of the air duct rotates to the position where the clip is misaligned to unlock it. Pull the drawer out, and then pull the push rod backward. The core ring at the front end of the push rod pulls the collar to compress the dust cover backward. Since the constraint ring at the rear end of the dust cover is fixed inside the air duct, continuing to pull the push rod backward can pull the core ring to support the collar and flip the dust cover backward out of the constraint ring. This allows the dust cover to be flipped inside and out along the end of the air duct, making it easier to clean the dust and impurities accumulated on the inner wall of the dust cover.

[0009] Preferably, the drawer is provided with a mounting plate to support the air intake component, the bracket is provided with two symmetrical drawer slides on both sides, the front of the bracket is provided with a locking hole corresponding to the operating component, and the front of the slide is provided with a backstop block.

[0010] Preferably, the outer end of the self-sealing tube is provided with a plurality of clamping pieces, each clamping piece being rotatably connected to the outer wall of the self-sealing tube via a side shaft, and the side shaft is provided with a torsion spring for pressing the end of the clamping piece against the outer wall of the air distribution tube, and the inner end of the clamping piece is provided with a claw for locking the air distribution tube.

[0011] Preferably, the cone disc has several fixed teeth at one end facing the air inlet assembly, and the push rod has a force-bearing ring at its rear end. The end face of the force-bearing ring has movable teeth corresponding to the fixed teeth. The fixed teeth and movable teeth are interlocking oblique tooth-shaped structures, and the movable teeth are provided with limiting grooves for restricting the axial displacement of the fixed teeth.

[0012] Preferably, a locking ring is fixed to the outer side of the tail end of the air distribution duct. The locking ring has a locking piece that cooperates with the clip, and a protruding edge connects adjacent locking pieces. The wall of the air distribution duct is densely covered with airflow holes, and a transmission end cap is fixed to its front end.

[0013] Preferably, a dust filter sleeve is coaxially sleeved inside the air distribution duct. A collar is provided on the inner side of the front end of the dust filter sleeve, and a constraint ring is provided on the rear end that is threadedly engaged with the inner wall of the air distribution duct. The collar is clearance-fitted with the inner wall of the air distribution duct and can be disengaged from the constraint ring.

[0014] Preferably, a core ring is fixed at the front end of the push rod, the core ring is rotatably engaged with the collar, and the core ring is detachably connected to the transmission end cover.

[0015] Preferably, the drawer includes a bottom plate and a tail hole plate. The tail hole plate is located on the front side of the air duct. Side plates connecting the tail hole plate are provided on both sides of the bottom plate. Guide wheels that cooperate with the slide rail are provided on the outside of the side plates. A cross brace is connected laterally between the two side plates. A connecting terminal is provided on the tail hole plate. A lock seat is provided at the front of the side plate.

[0016] Preferably, the operating component includes an operating shaft rotatably mounted on a mounting plate, a handle fixed at the front end of the operating shaft, an outwardly extending support arm fixed in the middle section, an eccentric shaft fixed at the outer end of the support arm, a transmission frame with clearance fitting on the outside of the eccentric shaft, a locking rod fixed at the bottom of the transmission frame that can sequentially pass through the upper and lower locking holes, and the operating shaft being connected to the transmission end cap via a synchronous belt drive to drive the self-sealing tube to rotate.

[0017] The beneficial effects are as follows: 1. By setting an independent self-sealing component, the present invention relies on the cooperation of a cone ring, a cone disc, and a spring to form an automatic closing mechanism, which can realize the automatic opening and closing of the air outlet of the air duct when the drawer is in place and when it is pulled out. When the drawer is pulled out and detached from the self-sealing component, the spring pushes the cone disc to fit against the sealing cone ring, automatically sealing the inner cavity of the self-sealing tube, blocking the airflow leakage from the air duct, ensuring the stable heat dissipation air pressure of the remaining drawers in the cabinet, and avoiding insufficient air pressure in the overall air duct and overheating of electrical components after a single drawer is pulled out; at the same time, the closed air duct can block external dust, moisture, and debris from entering the cabinet air duct and busbar area, avoiding terminal short circuits, insulation breakdown, and contact arcing caused by dust accumulation.

[0018] 2. A multi-level anti-disengagement locking structure is set up in layers to adapt to short-circuit impacts and equipment start-up and shutdown vibrations in the switchgear. During the drawer insertion stage, the torsion spring drives the clamping plates and claws to clamp the outer wall of the air duct. With the help of the locking ring protrusion, the drawer is pre-positioned and the axial slippage of the drawer is limited. The drawer slides out with the anti-reverse block at the end of the slide rail, which prevents the drawer from falling off the front end of the slide rail during assembly and protects the connection terminals and air duct structure from impact and deformation. During the closing operation, the locking rod of the operating component moves down and passes through the upper and lower locking holes to complete the axial mechanical locking of the drawer and bracket, limiting the back and forth movement of the drawer. At the same time, it drives the air intake component to rotate circumferentially, so that the clamping plates and locking plates bite and engage, completing the circumferential locking of the air duct insertion part and improving the stability of power distribution operation.

[0019] 3. The circuit closing, drawer locking, and air duct opening are integrated into one unit, which can be done simultaneously by rotating the handle on the outside of the panel. Rotating the handle simultaneously closes the circuit breaker to open the circuit, lowers the locking rod to lock the drawer, and rotates the air intake component to open the cooling air duct. Resetting the handle simultaneously opens the circuit, unlocks the drawer, and automatically closes the air duct. This solves the cumbersome operation process of traditional switchgear, which involves step-by-step closing, step-by-step locking, and manual sealing of air vents, simplifying the operation and maintenance steps. At the same time, the functions of each structure are interlocked. The air duct cannot be opened and the circuit cannot be closed when the drawer is not fully locked, forming a mechanical interlock protection. This effectively avoids high-risk operations such as pulling out the drawer under load or energizing the drawer without locking it, and is in line with the power distribution safety operation specifications.

[0020] 4. The drawer is equipped with an independent air intake component and dust filter cover. It adopts a separate assembly structure of collar and restraint ring. When cleaning accumulated dust, there is no need to disassemble the drawer or disassemble the air duct plug structure. Simply pull the push rod outward, and the core ring will drive the collar to pull the dust filter cover outward and remove it. The dust on the inner wall of the dust filter cover can be cleaned directly. Disassembly and cleaning are quick and labor-saving, shorten the maintenance and power outage time, and improve maintenance efficiency. Attached Figure Description

[0021] To more clearly illustrate the technical solutions in the embodiments of the present invention or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 This is a front view structural diagram of the present invention; Figure 2 This is a three-dimensional structural schematic diagram of the present invention; Figure 3 This is a schematic diagram of the internal structure of the present invention; Figure 4 This is a partial three-dimensional structural schematic diagram of the present invention; Figure 5This is a partial front view structural diagram of the present invention; Figure 6 This is a partial structural schematic diagram of another aspect of the present invention; Figure 7 This is a partial structural breakdown diagram of the present invention; Figure 8 This is a structural breakdown diagram of the bracket of the present invention; Figure 9 This is a three-dimensional structural schematic diagram of the air intake component of the present invention; Figure 10 This is a three-dimensional structural disassembled diagram of the air intake component of the present invention; Figure 11 This is a structural breakdown diagram of the self-sealing component of the present invention; Figure 12 This is a three-dimensional structural schematic diagram of the air distribution duct of the present invention; Figure 13 This is a three-dimensional structural diagram of the dust filter sleeve of the present invention; Figure 14 This is a partial structural schematic diagram of the self-sealing component of the present invention; Figure 15 This is a structural breakdown diagram of the operating components of the present invention; Figure 16 This is a structural disassembly diagram of the drawer of the present invention; Figure 17 This is a structural breakdown diagram of the panel of the present invention.

[0023] The annotations in the attached figures are explained as follows: 1. Cabinet; 2. Bracket; 201. Slide rail; 202. Lower lock hole; 203. Anti-reverse block; 3. Air duct; 301. Air vent; 4. Self-sealing assembly; 401. Self-sealing tube; 402. Clip; 402a. Claw; 403. Side shaft; 404. Torsion spring; 405. Conical ring; 406. Bracket ring; 406a. Connecting hole; 407. Closing rod; 407a. Spring; 407b. Limit nut; 408. Conical disc; 408a. Fixing tooth; 5. Drawer; 501. Base plate; 502. Tail hole plate; 503. Side plate; 503a. Lock seat; 504. Guide wheel; 505. Cross brace; 506. Connecting terminal; 6. Panel; 601. Status display screen; 602. Handle; 603. 604. Hinge; 604a. Moving section; 604b. Fixed section; 7. Mounting plate; 701. Support ear; 702. Mounting ear; 703. Locking hole; 704. Mounting cover; 8. Air inlet assembly; 801. Air distribution duct; 801a. Airflow hole; 802. Locking ring; 802a. Locking piece; 802b. Protruding edge; 803. Dust filter sleeve; 803a. Collar; 803b. Restraint ring; 804. Push rod; 805. Force ring; 806. Moving tooth; 807. Core ring; 808. Limiting groove; 809. Transmission end cover; 9. Operating assembly; 901. Operating shaft; 902. Handle; 903. Support arm; 903a. Eccentric shaft; 904. Transmission frame; 905. Locking rod. Detailed Implementation

[0024] The technical solutions of the embodiments of this application will be clearly described below with reference to the accompanying drawings. Obviously, the described embodiments are only some, not all, of the embodiments of this application. All other embodiments obtained by those skilled in the art based on the embodiments of this application are within the scope of protection of this application.

[0025] It should be noted that all directional and positional terms used in this invention, such as "up," "down," "left," "right," "front," "back," "vertical," "horizontal," "inner," "outer," "top," "lower," "lateral," "longitudinal," and "center," are only used to explain the relative positional relationships and connections between components in a specific state (as shown in the accompanying drawings). They are merely for the convenience of describing the invention and do not require the invention to be constructed and operated in a specific orientation; therefore, they should not be construed as limitations on the invention. Furthermore, descriptions involving "first," "second," etc., are for descriptive purposes only and should not be construed as indicating or implying their relative importance or implicitly specifying the number of technical features indicated.

[0026] In the description of this invention, unless otherwise explicitly specified and limited, the terms "installation," "connection," and "linking" should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral connection; they can refer to a mechanical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this invention based on the specific circumstances.

[0027] In the description of this specification, the references to terms such as "one embodiment," "some embodiments," "illustrative embodiment," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the invention. In this specification, the illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0028] See Figures 1-17 As shown, the present invention provides a withdrawable low-voltage switchgear, including a cabinet 1 and an air duct 3. The air duct 3 is vertically fixed inside the cabinet 1. Several sets of drawers 5 are vertically stacked inside the cabinet 1 in front of the air duct 3. The inner side of the cabinet 1 is provided with a bracket 2 that supports the front and rear sliding of the drawers 5. The front side of the air duct 3 is connected to a self-sealing component 4 provided for the corresponding drawer 5, which is used to automatically open and close the ventilation port of the air duct 3 in accordance with the insertion and removal action of the drawer 5, so as to realize the switching between sealing and ventilation of the air duct 3. The inner side of the drawer 5 has an air inlet component 8 that is inserted and connected to the front port of the self-sealing component 4, which is used to connect to the air duct 3 to deliver cooling airflow and provide positive pressure heat dissipation air for the electrical components inside the drawer 5. The self-sealing component 4 includes a self-sealing tube 401 connecting to the ventilation duct 3. A conical ring 405 is fixed inside the self-sealing tube 401. A support ring 406 is fixed to the inner side of the tail end of the self-sealing tube 401, and a closing rod 407 extends longitudinally through the inner side of the support ring 406. A conical disc 408 is fixed to the front side of the closing rod 407 to fit against the conical ring 405, thereby sealing the through hole of the conical ring 405, isolating the ventilation duct 3 from the outside, and realizing the automatic sealing of the ventilation duct 3. A spring 407a is sleeved on the outer side of the closing rod 407 to keep the conical disc 408 pressed against the surface of the conical ring 405. The spring 407a cooperates with the conical disc 408. The air inlet assembly 8 and the cone ring 405 form a closed mechanism. The air inlet assembly 8 includes an air distribution pipe 801 sleeved outside the self-sealing pipe 401, which is used to connect with the self-sealing pipe 401 to receive the airflow of the air duct 3, and at the same time complete the insertion and alignment and pre-fixation with the self-sealing assembly 4. The air distribution pipe 801 is provided with a push rod 804 that can push the cone plate 408 to disengage it from the cone ring 405. Thus, when the air inlet assembly 8 is inserted into the self-sealing assembly 4, the closing mechanism inside the self-sealing pipe 401 is opened, thereby guiding the air duct 3 and the internal channel of the air distribution pipe 801 to complete the connection operation of the heat dissipation air duct 3 of the single drawer 5.

[0029] As an optional implementation, the drawer 5 is provided with a mounting plate 7 that supports the air intake component 8, and the front of the drawer 5 is provided with a panel 6 that can be opened. The top side of the mounting plate 7 is provided with an operating component 9 that drives the air intake component 8 to rotate. The bracket 2 is provided with two symmetrically distributed slide rails 201 on both sides of the drawer 5, and the front side of the bracket 2 is provided with a vertically penetrating lower locking hole 202 corresponding to the operating component 9. The bottom edge of the front opening side of the slide rail 201 is provided with a backstop block 203. With this configuration, the slide rail 201 limits the sliding trajectory of the drawer 5, and the backstop block 203 prevents the drawer 5 from sliding out and slipping, which can improve the stability of the drawer 5's push-pull connection and prevent the drawer 5 from falling off the front end of the slide rail 201 and hitting the terminals during assembly. The front side of the air duct 3 is provided with several air holes 301 corresponding to the self-sealing component 4. The outer circumference of the bracket ring 406 is surrounded by multiple connecting holes 406a. The tail end of the closing rod 407 is threaded with a limit nut 407b. The outer end of the self-sealing tube 401 is surrounded by several sets of clamping pieces 402. The clamping pieces 402 and the outer wall of the self-sealing tube 401 are rotatably engaged by the side shaft 403. The side shaft 403 is sleeved with a torsion spring 404 to keep the end of the clamping piece 402 pressed against the outer wall of the air distribution tube 801. This is used to drive the clamping piece 402 to clamp inward in a normal state, realizing the pre-clamping limit after the air distribution tube 801 is inserted. The inner end of the clamping piece 402 is provided with an inwardly inclined claw 402a. With this configuration, the claw 402a can engage the locking ring 802 to complete the circumferential locking. The torsion spring 404 can automatically reset the clamping piece 402, realizing automatic opening and closing clamping when inserted and removed. A cone disc 408 near the air inlet assembly 8 has several sets of fixed teeth 408a arranged around its axis. A force ring 805 is fixed to the rear end of the push rod 804. The end face of the force ring 805 is provided with several sets of movable teeth 806 corresponding to the fixed teeth 408a. The fixed teeth 408a and the movable teeth 806 are interlocking helical tooth structures used for circumferential transmission engagement, which converts the rotational force of the air inlet assembly 8 into an axial pushing force. When the movable teeth 806 rotate, an axial component force is generated between the tooth surfaces, thereby driving the cone disc 408 to move axially along the closing rod 407 and disengage from the cone ring 405. The tip of the movable teeth 806 is provided with a limiting groove 808 to accommodate the tip of the fixed teeth 408a, thereby ensuring that the helical teeth do not deviate and the transmission alignment is accurate. With this configuration, the rotational action is converted into an axial pushing action, which is linked to unlock the air duct 3 closing mechanism. A locking ring 802 is fixed to the outer side of the tail end of the air duct 801. The locking ring 802 includes locking pieces 802a that are staggered with the clip 402. An arc-shaped protrusion 802b connects adjacent locking pieces 802a. The air duct 801 is densely covered with airflow holes 801a. A transmission end cap 809 is fixed to the front end of the air duct 801. A dust filter sleeve 803 is coaxially sleeved inside the air duct 801 to filter the cooling airflow entering the drawer 5 and prevent dust and debris from adhering to electrical components. The dust filter sleeve 803 is preferably made of a flexible filter mesh. The filter sleeve 803 has a structure that can undergo radial contraction and flipping deformation under axial tension. A collar 803a is fixed to the inner side of the front end of the dust cover 803, and a constraint ring 803b is fixed to the outer side of the rear end. The collar 803a is clearance-fitted with the inner wall of the air distribution duct 801, and the constraint ring 803b is threadedly fitted with the inner wall of the air distribution duct 801. The collar 803a can be disengaged from the constraint ring 803b to disassemble the front limiting structure of the dust cover 803. This design allows the dust cover 803 to be flipped out and removed without disassembling the air duct 3 structure, so as to quickly clean the attached dust. The front end of the push rod 804 is fixed with a core ring 807. The core ring 807 is rotatably engaged with the collar 803a. The core ring 807 is detachably connected to the transmission end cover 809 by bolts, thereby realizing the synchronous rotation of the push rod 804 and the air distribution pipe 801. At the same time, the push rod 804 can be disassembled separately, and the dust removal can be completed by pulling the dust filter sleeve 803. Drawer 5 includes a bottom plate 501 and a tail hole plate 502. The tail hole plate 502 is located on the front side of the air duct 3. Side plates 503 connected to the tail hole plate 502 are fixed on both sides of the bottom plate 501. Guide wheels 504 adapted to slide rail 201 are fixed on the outside of the side plates 503. A cross brace 505 is horizontally connected between the two side plates 503. A connecting terminal 506 extending backward is provided in the middle of the tail hole plate 502. A through hole-shaped lock seat 503a is provided at the front of the side plate 503. In addition, a handle 602 is provided on one side of the panel 6. A locking hook 603 that can be separated and locked to the lock seat 503a is provided at the rear of the handle 602. A status display screen 601 is provided on the front side of the panel 6. A hinge 604 is provided on the side of the panel 6 away from the handle 602. The hinge 604 includes a movable section 604a fixed to the panel 6 and a fixed section 604b fixed to the side plate 503. When the panel 6 needs to be opened separately, the handle 602 is pulled upward to disengage the locking hook 603 from the lock seat 503a. Then, with the support of the hinge 604, the panel 6 is opened forward separately. Therefore, the entire drawer 5 can be pulled out, and the panel 6 can be opened quickly to inspect the components at the front of the drawer 5 without pulling out the whole drawer 5, which improves the convenience of inspection. The top side of the mounting plate 7 is provided with a support ear 701 for supporting the operation component 9 and a mounting ear 702 for supporting the air inlet component 8. The bottom side of the mounting plate 7 is vertically perforated with an upper locking hole 703 corresponding to the lower locking hole 202. The front side of the support ear 701 is provided with a mounting cover 704 for mounting the operation component 9. The operating component 9 includes an operating shaft 901 rotatably mounted on a support ear 701. The front end of the operating shaft 901 extends out of the mounting cover 704 and is fixed with a handle 902. The middle section of the operating shaft 901 is fixed with an outwardly inclined support arm 903. The outer end of the support arm 903 is fixed with an eccentric shaft 903a. The eccentric shaft 903a is externally fitted with a horizontally extending transmission frame 904. The bottom of the transmission frame 904 is fixed with a locking rod 905 that passes through the upper locking hole 703 and the lower locking hole 202 in sequence. The locking rod 905 is driven to rise and fall vertically by means of the eccentric transmission structure, thereby completing the mechanical unlocking and locking of the drawer 5 and the bracket 2. The operating shaft 901 is externally provided with a synchronous belt that connects to the transmission end cover 809 to drive the self-sealing tube 401 to rotate. It can synchronously control the circumferential rotation of the air intake component 8 and synchronously complete the opening and closing of the air duct 3 and the clamping and locking operation.

[0030] Using the above structure, when the drawer 5 and its internal electrical components need to be inserted into the set position bracket 2 inside the cabinet 1, the tail section of the drawer 5 is placed into the top side of the bracket 2 and pushed backward until the tail end of the air distribution pipe 801 of the rear air intake assembly 8 of the drawer 5 is inserted into the outside of the self-sealing pipe 401 of the self-sealing assembly 4. At this time, the connection terminal 506 of the drawer 5 is connected to the fixed terminal of the cabinet 1. During the process of inserting the tail end of the air inlet assembly 8 into the front end of the self-sealing assembly 4, the locking piece 802a of the air distribution duct 801 and the clamping piece 402 of the self-sealing tube 401 are in an interleaved state, that is, the front end of the self-sealing tube 401 allows the tail end of the air distribution duct 801 to be inserted and engaged. At this time, the air distribution duct 801 is sleeved around the outside of the self-sealing tube 401. As the protruding edge 802b of the air distribution duct 801 moves backward, it expands outward to support the clamping piece 402. Under the action of the torsion spring 404, the clamping piece 402 is clamped to the outer wall of the air distribution duct 801. The protruding edge 802b cooperates with the clamping piece 402 to restrict the air distribution duct 801 from moving forward and backward, thereby pre-positioning the drawer 5 as a whole and preventing the drawer 5 from slipping out. At the same time, the movable tooth 806 of the force ring 805 at the front end of the push rod 804 moves backward to the position of the fixed tooth 408a of the meshing cone 408, and the force ring 805 fits tightly against the cone 408, keeping the rear self-sealing component 4 in a closed state. When it is necessary to rotate the handle 902 at position 6 of the panel to conduct the internal circuit of the drawer 5, since the operating shaft 901 at the rear end of the handle 902 is connected to the circuit breaker switch, that is, the tail end of the operating shaft 901 is inserted into the operating hole of the circuit breaker rocker arm, rotating the handle 902 will rotate the operating shaft 901 to drive the circuit breaker to close, thereby conducting the internal circuit of the drawer 5 at that position. At the same time, the support arm 903 connected to the outer end of the operating shaft 901 will drive the eccentric shaft 903a to rotate downward. The eccentric shaft 903a drives the transmission frame 904 to move the locking rod 905 downward. The locking rod 905 passes down through the upper locking hole 703 into the lower locking hole 202, thereby locking the drawer 5 as a whole onto the bracket 2, completing the mechanical locking of the front and rear positions of the drawer 5. While drawer 5 is locked, operating shaft 901 drives transmission end cover 809 of air intake assembly 8 to rotate via synchronous belt. Transmission end cover 809 drives air intake assembly 8 to rotate as a whole. Air duct 801 of air intake assembly 8 rotates to the position where external locking piece 802a coincides with clamping piece 402 of self-sealing tube 401. The wedge-shaped claw 402a of clamping piece 402 locks the front and rear positions of air duct 801 by locking the matching locking piece 802a, thus achieving secondary locking of drawer 5 position. During the rotation and locking process of the air inlet assembly 8, the force ring 805 drives the movable tooth 806 to rotate synchronously. The movable tooth 806 with the helical tooth structure pushes the fixed tooth 408a of the self-sealing assembly 4 outward, thereby pushing the fixed tooth 408a and the cone plate 408 away from the cone ring 405, thus pushing the cone plate 408 and the cone ring 405 apart to open the air inlet channel. At the same time, the spring 407a is compressed and stored to automatically close the air inlet channel when the drawer 5 is pulled out. The air duct 3 is connected to the external cooling fan. The airflow enters the air distribution duct 801 along several sets of self-sealing components 4. After being filtered and collected by the dust filter sleeve 803 inside the air distribution duct 801, the gas is discharged into the corresponding drawer 5 along the air distribution duct 801, forming a positive pressure airflow for heat dissipation in the drawer 5. When removing drawer 5, rotate handle 902 to reset, lock lever 905 moves upward, and air distribution tube 801 reverses. Movable tooth 806 engages with fixed tooth 408a again, cone disc 408 automatically closes the inner cavity of self-sealing tube 401 against cone ring 405, and locking piece 802a of air distribution tube 801 rotates to the misaligned position of clip piece 402 to unlock, allowing drawer 5 to be pulled out. Then, pull push rod 804 backward, utilizing the core ring 807 at the front end of push rod 804. Pulling the collar 803a causes the dust filter sleeve 803 to compress backward. Since the constraint ring 803b at the rear end of the dust filter sleeve 803 is fixed inside the air distribution duct 801, continuing to pull the push rod 804 backward can pull the core ring 807 to drive the collar 803a to support the dust filter sleeve 803 to flip backward out of the constraint ring 803b, thereby flipping the dust filter sleeve 803 inside and out along the tail end of the air distribution duct 801 and pulling it out, which makes it easier to clean the dust and impurities accumulated on the inner wall of the dust filter sleeve 803.

[0031] By setting an independent self-sealing component 4, relying on the cooperation of the cone ring 405, cone plate 408, and spring 407a to form an automatic closing mechanism, the air outlet of the air duct 3 can be automatically opened and closed when the drawer 5 is in position or pulled out. When the drawer 5 is pulled out and detached from the self-sealing component 4, the spring 407a pushes the cone plate 408 to fit against the sealing cone ring 405, automatically sealing the inner cavity of the self-sealing tube 401, blocking the airflow leakage of the air duct 3, ensuring the stable heat dissipation air pressure of the remaining drawers 5 in the cabinet, and avoiding insufficient air pressure of the overall air duct 3 and overheating of electrical components after a single drawer 5 is pulled out; at the same time, sealing the air duct 3 can prevent external dust, moisture, and debris from entering the air duct 3 and busbar area of ​​the cabinet 1, avoiding terminal short circuits, insulation breakdown, and contact arcing caused by dust accumulation.

[0032] The multi-level anti-disengagement locking structure is layered to adapt to short-circuit impacts and equipment start-up and shutdown vibrations in the switchgear. During the insertion stage of drawer 5, the torsion spring 404 drives the clamping piece 402 and the claw 402a to clamp the outer wall of the air duct 801. With the cooperation of the locking ring 802 and the protruding edge 802b, the drawer 5 is pre-positioned for insertion, limiting the axial slippage of drawer 5. The anti-reverse block 203 at the end of the slide rail 201 limits the drawer 5 from sliding out, preventing drawer 5 from falling off the front end of the slide rail 201 during assembly and protecting the connection terminal 506 and the air duct 3 structure from impact and deformation. During the closing operation, the locking rod 905 of the operating component 9 moves down and passes through the upper locking hole 703 and the lower locking hole 202 to complete the axial mechanical locking of drawer 5 and bracket 2, limiting the back-and-forth movement of drawer 5. At the same time, it drives the air intake component 8 to rotate circumferentially, so that the clamping piece 402 and the locking piece 802a engage and lock, completing the circumferential locking of the air duct 3 insertion part, improving the stability of power distribution operation.

[0033] The circuit closing, drawer 5 locking, and air duct 3 opening are integrated into one unit, which can be done simultaneously by rotating the handle 902 on the outside of the panel 6. Rotating the handle 902 simultaneously closes the circuit breaker and opens the circuit, lowers the locking rod 905 to lock the drawer 5, and rotates the air intake component 8 to open the cooling air duct 3. Resetting the handle 902 simultaneously opens the circuit, unlocks the drawer 5, and automatically closes the air duct 3. This solves the cumbersome operation process of traditional switchgear, which involves step-by-step closing, step-by-step locking, and manual sealing of air vents, simplifying the operation and maintenance steps. At the same time, the functions of each structure are interlocked. If the drawer 5 is not fully locked, the air duct 3 cannot be opened and the circuit cannot be closed, forming a mechanical interlock protection. This effectively avoids high-risk operations such as pulling out the drawer 5 under load or energizing the drawer 5 without locking it, and is in line with the power distribution safety operation specifications.

[0034] The drawer 5 is equipped with an independent air intake component 8 and a dust filter cover 803. It adopts a separate assembly structure of collar 803a and constraint ring 803b. When cleaning accumulated dust, there is no need to disassemble the drawer 5 or disassemble the plug-in structure of the air duct 3. Simply pull the push rod 804 outward, and the core ring 807 will drive the collar 803a to pull the dust filter cover 803 outward to directly clean the dust on the inner wall of the dust filter cover 803. The disassembly and cleaning is quick and labor-saving, shortens the maintenance downtime, and improves maintenance efficiency.

[0035] The dimensions, shapes, installation positions, and connection methods of each structural component in this application can be adaptively designed according to the rated current level of the switchgear, the specifications of the drawer unit, the air duct layout, and the cabinet space dimensions. To ensure the reliable implementation of the drawer 5's insertion, locking, closing, and air duct conduction actions, the operating component 9, the air inlet component 8, the self-sealing component 4, and the circuit breaker operating mechanism preferably satisfy a sequential linkage relationship. That is, after the drawer 5 completes the insertion and positioning, it first establishes the air duct connection pre-positioning state, then drives the locking rod 905 through the operating shaft 901 to complete the mechanical locking, then drives the air inlet component 8 to open the self-sealing component 4, and finally drives the circuit breaker operating mechanism to complete the circuit conduction. During the reset process, the reverse sequence is followed, thereby ensuring that the air duct closes after the circuit breaker is opened, the drawer unlocks after the air duct is closed, and the drawer can only be pulled out after it is unlocked, forming a mechanical interlock relationship.

[0036] The stroke difference, operating angle, preload, locking force, and transmission torque of the above-mentioned mechanisms can be adaptively designed according to the drawer capacity level, circuit breaker specifications, and air duct resistance. Those skilled in the art can complete the corresponding parameter matching based on existing mechanical design methods to ensure that each mechanism has sufficient operational reliability, locking stability, and service life during long-term operation.

[0037] Material selection, structural dimensions, tolerances, processing techniques, installation methods, and control parameters not described in detail in this invention can all be conventionally designed and optimized by those skilled in the art based on actual application scenarios without departing from the concept of this invention, and all of these fall within the protection scope of this invention.

[0038] The above description is merely a specific embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A withdrawable low-voltage switchgear, comprising a cabinet (1), an air duct (3) disposed within the cabinet (1), and a drawer (5) that can be pulled out along a bracket (2) within the cabinet (1), characterized in that: The front side of the air duct (3) is provided with a self-sealing component (4) corresponding to the drawer (5), and the rear side of the drawer (5) is provided with an air inlet component (8) that can be plugged into the self-sealing component (4). The self-sealing component (4) is provided with a normally closed closing mechanism. When the air inlet component (8) is inserted into the position, it can drive the closing mechanism to open, so as to guide the airflow passage between the ventilation duct (3) and the drawer (5). The drawer (5) is provided with an operating component (9), which can drive the locking mechanism between the drawer (5) and the bracket (2) to operate, and simultaneously drive the air intake component (8) and the self-sealing component (4) to form a locking engagement; When the drawer (5) disengages from the self-sealing assembly (4), the closing mechanism automatically resets and seals the air duct (3).

2. The withdrawable low-voltage switchgear according to claim 1, characterized in that: The self-sealing assembly (4) includes a self-sealing tube (401) connected to the ventilation duct (3). A conical ring (405) is fixed inside the self-sealing tube (401). A support ring (406) is fixed inside the tail end of the self-sealing tube (401). A closing rod (407) is axially slidably mounted on the support ring (406). A conical disc (408) that fits against the closing conical ring (405) is fixed to the front side of the closing rod (407). A retaining conical disc (408) is sleeved on the outside of the closing rod (407) to keep it pressed against the conical ring (405). The spring (407a) on the surface of the air inlet assembly (8) is used in conjunction with the cone disc (408) and the cone ring (405) to form a closing mechanism. The air inlet assembly (8) includes a distribution pipe (801) sleeved outside the self-sealing pipe (401). The distribution pipe (801) is provided with a push rod (804) inside, which can push the cone disc (408) to disengage it from the cone ring (405). When the air inlet assembly (8) is inserted into the outside of the self-sealing assembly (4), the closing mechanism inside the self-sealing pipe (401) is opened by pushing.

3. The withdrawable low-voltage switchgear according to claim 2, characterized in that: The drawer (5) is provided with a mounting plate (7) that supports the air intake component (8). The bracket (2) is provided with two slide rails (201) symmetrically distributed on both sides of the drawer (5). The front side of the bracket (2) is provided with a lower locking hole (202) corresponding to the operating component (9). The front side of the slide rail (201) is provided with a backstop block (203).

4. The withdrawable low-voltage switchgear according to claim 3, characterized in that: The outer end of the self-sealing tube (401) is surrounded by a plurality of clips (402). Each clip (402) is rotatably connected to the outer wall of the self-sealing tube (401) via a side shaft (403). The side shaft (403) is provided with a torsion spring (404) to press the end of the clip (402) against the outer wall of the air distribution tube (801). The inner end of the clip (402) is provided with a claw (402a) for locking the air distribution tube (801).

5. A withdrawable low-voltage switchgear according to claim 4, characterized in that: The cone disc (408) has a plurality of fixed teeth (408a) at one end facing the air inlet assembly (8), and the push rod (804) has a force ring (805) at the rear end. The end face of the force ring (805) has movable teeth (806) corresponding to the fixed teeth (408a). The fixed teeth (408a) and the movable teeth (806) are interlocking oblique tooth structures, and the movable teeth (806) are provided with a limiting groove (808) for limiting the axial displacement of the fixed teeth (408a).

6. The withdrawable low-voltage switchgear according to claim 4, characterized in that: A locking ring (802) is fixed to the outer side of the tail end of the air distribution duct (801). The locking ring (802) has a locking piece (802a) that cooperates with the clip (402), and a protruding edge (802b) connects adjacent locking pieces (802a). The air distribution duct (801) has airflow holes (801a) densely distributed on its wall, and a transmission end cap (809) is fixed to its front end.

7. A withdrawable low-voltage switchgear according to claim 6, characterized in that: The air distribution duct (801) is coaxially fitted with a dust filter sleeve (803). The dust filter sleeve (803) has a collar (803a) on the inner side of its front end and a constraint ring (803b) that is threaded to the inner wall of the air distribution duct (801) at its rear end. The collar (803a) is in clearance fit with the inner wall of the air distribution duct (801) and can be dislodged from the constraint ring (803b) in the rear.

8. A withdrawable low-voltage switchgear according to claim 7, characterized in that: The push rod (804) has a core ring (807) fixed at its front end. The core ring (807) is rotatably engaged with the collar (803a). The core ring (807) is detachably connected to the transmission end cover (809).

9. A withdrawable low-voltage switchgear according to claim 8, characterized in that: The drawer (5) includes a bottom plate (501) and a tail hole plate (502). The tail hole plate (502) is located on the front side of the air duct (3). The bottom plate (501) has side plates (503) on both sides that connect to the tail hole plate (502). The side plates (503) have guide wheels (504) that cooperate with the slide rail (201) on their exterior. The two side plates (503) are connected laterally by a cross brace (505). The tail hole plate (502) has a connecting terminal (506). The side plate (503) has a lock seat (503a) at the front.

10. A withdrawable low-voltage switchgear according to claim 9, characterized in that: The operating component (9) includes an operating shaft (901) rotatably mounted on the mounting plate (7). The operating shaft (901) has a handle (902) fixed at its front end and an outwardly extending support arm (903) fixed in its middle section. An eccentric shaft (903a) is fixed at the outer end of the support arm (903). A transmission frame (904) is fitted to the outer side of the eccentric shaft (903a) with a clearance. A locking rod (905) is fixed at the bottom of the transmission frame (904) and can pass through the upper locking hole (703) and the lower locking hole (202) in sequence. The operating shaft (901) is connected to the transmission end cover (809) via a synchronous belt to drive the self-sealing tube (401) to rotate.

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