83results about How to "Reduce impact noise" patented technology

The utility model relates to the field of electromagnetic valves, and discloses a mute electromagnetic valve. The mute electromagnetic valve comprises a framework provided with a cavity, a coil is arranged on the peripheral wall of the framework, a movable iron core and a static iron core are coaxially arranged in the cavity, a mute pad is arranged at the end, facing the movable iron core, of the static iron core in a sleeved mode, a protruding ring is arranged at the end, facing the movable iron core, of the mute pad, and when the movable iron core and the static iron core attract each other, the movable iron core and the static iron core attract each other. Through the design that the annular end face of the convex ring abuts against the end face of the movable iron core, the impact contact area generated when the movable iron core and the static iron core are attracted is reduced, and the impact noise generated when the movable iron core and the static iron core are attracted can be effectively reduced.

The embodiment of the utility model discloses a universal wheel assembly and cleaning equipment with the universal wheel assembly. The universal wheel assembly comprises a universal wheel support and a universal wheel, the universal wheel is accommodated in the universal wheel support and can rotate around a universal wheel shaft; wherein the upper surface of the universal wheel support is provided with a cavity covering part, and the cavity covering part is used for sealing a cavity in the upper surface of the universal wheel support. According to the universal wheel assembly, the amplitude of the shell can be reduced when the universal wheel assembly collides with other objects, the amplification effect of the cavity on sound generated by collision is reduced, the collision sound is reduced, and the noise reduction effect is achieved.

The utility model belongs to the technical field of mechanical transmission, and particularly relates to an assembly type planetary gear transmission assembly. The utility model provides an assembly type planetary gear transmission assembly. The assembly type planetary gear transmission assembly comprises a fixing frame, a gear ring elastically installed in the fixing frame, a sun gear coaxial with the gear ring and a plurality of planetary gears connected between the gear ring and the sun gear in a meshed mode. The planet gear is rotationally arranged on the planet carrier, the planet carrier is a first power connecting end, and the sun gear is a second power connecting end; clamping structures are formed on the inner side of the fixing frame and the outer side of the gear ring, and an elastic gasket is connected between the inner side of the fixing frame and the outer side of the gear ring in a clamped mode. According to the assembly type planetary gear transmission assembly, balanced distribution of torque of the planetary gear can be achieved, vibration, noise and tooth surface abrasion generated by meshing of the planetary gear and the gear ring are effectively reduced, and therefore the transmission efficiency is improved, and the service life is prolonged.

The utility model relates to generator set auxiliary equipment technical field discloses a diesel generating set mute big cover convenient for overhauling, including cover body, the cover body top is equipped with the cover body that is composed of two symmetrical cover plates, and the cover plate is through the sliding block and the inverted T type sliding slot of cover body top sliding fit, the inner wall of cover body is equipped with buffer mechanism, and the support arm of buffer mechanism is supported through the elastic support rod, and the support arm end is equipped with gyro wheel no.

The present invention discloses a Roots blower with a guide device, comprising a casing, the casing is provided with an air inlet and an exhaust port, the air inlet is provided with an air inlet guide cone, an air inlet flow channel is formed between the air inlet guide cone and the inner wall of the air inlet, the exhaust port is provided with an air outlet guide cone, an air outlet flow channel is formed between the air outlet guide cone and the inner wall of the exhaust port, an exhaust cavity with openings at both ends is provided inside the air outlet guide cone, an exhaust hole connected to the exhaust cavity is provided on the casing, the air inlet guide cone and the exhaust guide cone have concave arc surfaces on the side facing the impeller, and a limit protection valve is provided on the side facing the impeller of the air outlet guide cone. By providing the guide cone, a longer flow channel can effectively delay the reflux process of high-pressure gas, and even if the gas enters the volume formed by the impeller and the casing along the flow channels on both sides of the two guide cones, the generation of gas turbulence can be effectively avoided, thereby solving the problem of high noise of the current blower.

The invention provides a plunger pump single body and a plunger pump. The plunger pump single body comprises a shell, two plungers arranged in the shell and a driving piece for driving the two plungers to do linear reciprocating motion at the same time. Wherein the driving part comprises an eccentric wheel, a main shaft used for driving the eccentric wheel to rotate and two driving shafts used for driving the two plungers to do linear reciprocating motion respectively, the driving shafts are arranged in a sliding way in the shell in a sliding mode, one ends of the driving shafts make contact with the outer contour wall of the eccentric wheel through driven wheels, and the other ends of the driving shafts are coaxially connected with the plungers; the eccentric wheel is positioned between the two driven wheels; a buffer layer is arranged on the outer contour wall of the driven wheel and / or the outer contour wall of the eccentric wheel. According to the plunger pump, the buffer layer is arranged on the driven wheel and / or the eccentric wheel, impact generated on the driven wheel in the rotating process of the eccentric wheel is buffered through the buffer layer, impact noise is reduced, impact on the main shaft is reduced, accordingly, radial stress abrasion of the main shaft bearing is reduced, and the service life of the main shaft bearing is prolonged.

The utility model relates to the technical field of printing machine scrapers, in particular to an SMT printing machine scraper which comprises a connecting box, a plurality of adjusting assemblies are arranged at the lower end of the connecting box, pressure sensors are arranged on the adjusting assemblies, buffer blocks are arranged at the lower ends of the adjusting assemblies, and a supporting plate is arranged at the lower ends of the buffer blocks. A main knife is arranged on the bottom wall of the supporting plate, an auxiliary knife sleeve is arranged at the lower end of the main knife, the auxiliary knife sleeve is matched with the main knife and is in damping sliding connection with the main knife, a connecting shaft is arranged at the upper end of the connecting box, the adjusting assembly comprises a control box, a motor, a supporting rod, an adjusting rod and an adjusting block, and baffles are arranged at the two ends of the bottom wall of the supporting plate. The buffer block is of a multi-layer composite elastomer structure, dynamic balance of pressure in different areas of the scraper is achieved, impact noise generated when the scraper works is effectively reduced, and the scraper is particularly suitable for precise printing of high-viscosity solder paste.

The invention provides an engine intake and exhaust system state evaluation method and system based on heterogeneous data. The method comprises the steps that a vibration signal and a thermotechnical signal under a diesel engine intake and exhaust system fault simulation test are acquired; performing wavelet transform on the vibration signal to obtain a combined wavelet feature, extracting a time domain feature of the vibration signal, and performing feature combination on the wavelet feature, the time domain feature and the thermotechnical signal to obtain a diesel engine motion state feature vector; and obtaining an optimized SVM model based on a particle swarm algorithm, and carrying out online state evaluation on the intake and exhaust system of the engine based on the SVM model. According to the method, the problems that the signal interference of a high-power multi-cylinder diesel engine is large and the accuracy rate of an existing intake and exhaust system state evaluation method taking a single information source as a diagnosis basis is low are solved to a certain extent, meanwhile, end-to-end intelligent online evaluation can be achieved, few hardware resources are consumed, and the method has good engineering application prospects.

The utility model discloses a uniformly-abraded SUV (sports utility vehicle) tire pattern and a tire, and relates to the technical field of tires. The utility model discloses a uniformly-abraded SUV (sports utility vehicle) tire pattern which comprises a plurality of pattern blocks with unequal pitches, wherein the pattern blocks extend and are distributed along the circumferential direction of a tread; the pattern blocks of each pitch comprise a middle pattern block, and middle rib pattern blocks and shoulder pattern blocks which are positioned on two sides of the middle pattern block and are sequentially distributed; middle longitudinal main grooves are formed between the middle pattern blocks and the middle rib pattern blocks which are adjacent to each other, and shoulder longitudinal main grooves are formed between the middle rib pattern blocks and the shoulder pattern blocks which are adjacent to each other; a middle Z-shaped groove is formed in the middle pattern block of each pitch, and middle rib pattern blocks on the two sides of each pitch are each provided with a middle rib S-shaped groove. According to the utility model, the long Z-shaped and S-shaped grooves are designed on the tire pattern, so that the pattern blocks are uniformly divided, the tire is easy to uniformly abrade, the long mileage and the long service life of the tire are further realized, and the impact noise is reduced.

The utility model discloses a high-grip SUV (sports utility vehicle) tire pattern and a tire, and relates to the technical field of tires. The tire comprises a plurality of pattern blocks with unequal pitches, wherein the pattern blocks extend and are distributed along the circumferential direction of a tread; the pattern blocks of each pitch comprise a middle pattern block, and middle rib pattern blocks and shoulder pattern blocks which are positioned on two sides of the middle pattern block and are sequentially distributed; middle longitudinal main grooves are formed between the middle pattern blocks and the middle rib pattern blocks which are adjacent to each other, and shoulder longitudinal main grooves are formed between the middle rib pattern blocks and the shoulder pattern blocks which are adjacent to each other; and the middle pattern block of each pitch is provided with two central short grooves which are in central symmetry and two central inclined short and thin grooves which are in central symmetry. According to the utility model, the middle pattern blocks are provided with more central inclined short and thin grooves and central thin grooves, and the middle pattern blocks are divided, so that the tread becomes soft, the tread can be in full contact with a road surface, and the road holding force of the tire on various road conditions, especially on a wet and slippery road surface, is enhanced.

The recovery training device comprises a bottom plate and a vertical frame, a storage box is fixed to one side of the top end of the bottom plate, guide rails are fixed to the left side and the right side of the top end of the storage box, sliding blocks are connected to the inner sides of the guide rails in a sliding mode, and a supporting table is fixed to the side, close to the central axis of the storage box, of each sliding block; a vertical rod is fixed to the middle of the top end of the supporting table, a balancing weight is arranged outside the vertical rod, a connector is arranged at the top end of the balancing weight, a steel cable is fixed to the top end of the connector, and a buffering air bag is fixed to the middle of the top end of the storage box. Compared with an existing recovery training device, the recovery training device has the advantages that the buffer mechanism is arranged, impact force generated by weight falling can be absorbed during training, noise and vibration of the device are reduced, disturbance to residents or patients in floors is reduced, meanwhile, the device is provided with the lifting chair structure, and the lifting chair structure is convenient to use. A patient can adjust the height of the chair according to own use requirements, so that the applicability of the device is improved.

The utility model discloses a sound insulation and noise reduction industrial lifting door which comprises a door frame, an inner cavity of the door frame is connected with a door plate in a sliding mode, and sliding rail assemblies are arranged on the two sides of the door plate. A plurality of connecting mechanisms are arranged on the sliding rail assembly, a pulling mechanism is arranged at one end of the fixing block, and the pulling mechanism comprises a fixing base fixed to one end of the sliding rail assembly; the insertion hole is formed in the top of the fixed seat; the folding and unfolding assembly is arranged at the top of the fixed seat; the jacking assembly is fixed to the bottom of the inner wall of the fixing base. And the dust board is fixed at one end of the fixed seat. The sliding rail assembly, the connecting mechanism and the pulling mechanism are arranged in a matched mode, the door plate can silently slide on the sliding rail assembly through the connecting mechanism, and when the door plate is moved to the position above the sliding rail assembly through the jacking assembly, impact damage of the door plate and the pressing switch and impact noise are reduced, and the safety of the door plate is improved. And through the retractable assembly, the use stability of the door plate is improved, and later maintenance is facilitated.

The utility model relates to the technical field of swimming pool water outlet, disclose a straight -in type water mouth with side water outlet. It aims at solving the technical problem of low work efficiency of big workload that the water outlet direction setting is on the top cover in the prior art, and the design of vertical direction leads to the dust and sundries of pool bottom gathering at the water outlet position, and only can use the dirt -suction machine to clean, the workload is big, and the work efficiency is low. The utility model includes base, detachable installation top cover above base, set up a plurality of side water outlets on the side of base, base is connected with backwater pipe through side water outlet to form water flow channel, annular supporting block is set up in the inner wall of backwater pipe to support adjustable pressing plate, adjustable pressing plate is installed in the middle of adjustable screw rod, adjustable screw rod is installed in hollow cylindrical structure, hollow cylindrical structure is fixed in annular supporting block through connecting rod, the thread of adjustable screw rod is set up in the inner wall of hollow cylindrical structure. The utility model has the advantages of saving construction time, high work efficiency, low construction difficulty and the like.

This utility model discloses an anti-rotation structure and its oil-free scroll compressor, comprising: a moving disc, on the outer circumferential side of which are at least three first protrusions; a housing, on the side of which adjacent to the moving disc are at least three second protrusions corresponding one-to-one with the first protrusions; and a flange eccentric sleeve connected to a first bearing installed in the second protrusions, wherein a cylindrical pin extending into the flange eccentric sleeve is installed in the first protrusion. This utility model has a simple structure. By changing the large clearance fit between the cylindrical pin and the ring sleeve to a small clearance fit between the cylindrical pin and the flange eccentric sleeve, the fit clearance is effectively reduced, significantly lowering the impact noise between the cylindrical pin and the mating parts. The small clearance fit enhances the stability of the moving pair, suppresses the overturning phenomenon of the moving disc caused by the large clearance, and improves the smoothness and reliability of the compressor operation. It combines the advantages of the pin sleeve anti-rotation structure and the three-crank structure.

This utility model belongs to the field of fan blade technology and discloses a multi-blade noise-reducing blower fan blade, including: a fan blade assembly comprising 53 forward-curved fan blades evenly distributed along the circumference of a hub, with a motor mounting cavity at the center of the hub; the axial end face of the hub has several heat dissipation holes, arranged equidistantly along the circumference to form an annular heat dissipation channel; a motor assembly comprising a thickened silicon steel sheet frame, the silicon steel sheet thickness being 0.5-0.8mm; the ratio of the fan blade diameter D to the fan outer diameter D0 is 75%-78%; this utility model, by using 53 forward-curved fan blades with an optimized bending angle of 15°-25°, and a chord length ratio of the leading edge to the trailing edge of the blades of 1:0.8-1:0.9, effectively suppresses turbulence and eddy noise. An arc-shaped transition section with a transition radius R = 3-5mm is provided at the connection between the hub and the fan blades to reduce airflow separation noise.

This invention discloses a low-noise hydraulic cylinder with adjustable end stroke and its assembly method, belonging to the field of ship vibration reduction and noise reduction technology. The cylinder includes a bow end cap, cylinder barrel, piston, connecting rod, buffer sleeve, stern end cap, and structures such as a reversing oil passage, a buffer oil passage, a reversing oil chamber, and a buffer oil chamber. The buffer sleeve is fitted onto both sides of the connecting rod, forming a closed buffer oil chamber in cooperation with the end cap, cylinder barrel, and piston. During operation, the oil flow rate and pressure of the buffer oil chamber are controlled by adjusting the oil pressure at the buffer port, achieving precise adjustment of the piston and connecting rod end stroke, avoiding rigid collision between the piston and the end cap, and suppressing impact noise at the source. This invention has a compact structure, reliable sealing, and convenient assembly, significantly reducing vibration impact and operating noise, improving the stealth of ships, and is suitable for scenarios with high vibration reduction and noise reduction requirements, such as the opening and closing of ship hull covers.

The utility model relates to the technical field of anti-theft doors, in particular to an anti-collision anti-theft door. The anti-theft door solves the technical problems that when a traditional anti-theft door is used and the anti-theft door is violently impacted, a plate-shaped structure of the anti-theft door possibly deforms due to impact force, so that the anti-theft door is damaged, and the safety of the anti-theft door is influenced. According to the technical scheme, the anti-collision anti-theft door comprises a door frame, an opening and closing assembly, an operation assembly, a noise reduction assembly, a buffering assembly, a reinforcing assembly and a supporting assembly; compared with the prior art that when a traditional anti-theft door is impacted violently, a plate-shaped structure is likely to deform due to impact force, so that the anti-theft door is damaged, and the safety of the anti-theft door is affected, the anti-theft door buffers the impact force through the buffer protection structure when the anti-theft door is impacted, and therefore the anti-theft door is protected. The stability of the anti-theft plate structure is improved through the reinforcing structure, the possibility that the anti-theft door is greatly deformed after being subjected to the device is reduced through the supporting structure, and therefore the anti-collision performance of the anti-theft door is improved.

The utility model discloses a novel noise reduction exhaust system of in-line four cylinder engine belongs to engine exhaust technical field, solves the problem of big exhaust noise of existing in-line four cylinder engine. It includes with the first cylinder exhaust passage, second cylinder exhaust passage, third cylinder exhaust passage, fourth cylinder exhaust passage of in-line four cylinder engine's four combustion chamber - corresponding connection first cylinder exhaust manifold, second cylinder exhaust manifold one end common connection has first exhaust branch pipe, third cylinder exhaust manifold, fourth cylinder exhaust manifold one end common connection has second exhaust branch pipe, first exhaust branch pipe, second exhaust branch pipe one end common connection has the exhaust pipe, first cylinder exhaust manifold with the exhaust pipe between, second cylinder exhaust manifold with the exhaust pipe between all is equipped with the shunt passage of the both intercommunication. The utility model's exhaust system effectively reduces the main gas flow noise of exhaust, prolongs the service life of engine.

The utility model provides a kind of spherical elbow belongs to pipe fitting technical field.It solves the problem of uneven distribution of fluid at branch and generation of larger noise in the prior art multi-channel elbow.The spherical elbow includes main pipe body, the main pipe body has several branch pipe bodies respectively with the communication of main pipe body, the main pipe body is spherical, the inner wall of each branch pipe body has several flow guide protrusions, the flow guide protrusions are spirally extended from the water inlet end of branch pipe body to the water outlet end, the pipe wall of branch pipe body has noise reduction hole along the length direction of branch pipe body, the noise reduction hole has multiple and is interval setting along the circumference of branch pipe body.The utility model has the advantage of solving the problem of larger noise generated during use of existing multi-channel elbow.

This application discloses an architectural planning and design model sand table, belonging to the field of sand table technology. The model sand table includes a base, a box mounted on the base, and a main body of the model sand table located at the end of the box away from the base. The box is equipped with a storage mechanism for storing the main body of the model sand table. The storage mechanism includes a frame that moves axially on the box, a drive component mounted on the box for moving the frame closer to or away from the base, and a dustproof cover at the end of the frame away from the base. Through the cooperation of the height-adjustable frame and the dustproof cover, the model sand table achieves the dual functions of dustproof storage and enclosure protection. During storage, the frame can be raised above the model's height using the drive component, and then the dustproof cover can be closed to effectively isolate dust. During display, the frame can be adjusted to a suitable height to form a fence surrounding the model, reducing damage from external collisions and improving the practicality and protection of the sand table.

A scroll compressor is disclosed. A scroll compressor according to an embodiment of the present invention comprises: a compression part for discharging, to the inner space of a casing, a refrigerant compressed in a compression chamber; a discharge port for forming a flow path through which the refrigerant compressed in the compression chamber is discharged to the outside of the compression chamber; and a valve member, which has, at one end portion thereof, a root part fixed to a valve seat part of the compression part, forms a free end on the other end portion thereof, and has a head part to open / close the discharge port. A spacing part is provided between the head part of the valve member and the valve seat part to space the head part from the valve seat part in a state in which the compression part stops. Therefore, during operation of the valve member, the moving speed of the head part is reduced by means of the stiffness of the valve member so that impact force generated when the head part of the valve member collides with one surface of the compression part is reduced and impact noise generated thereby can be decreased.

The application discloses a noise-reducing energy-saving environment-friendly transformer, which comprises a lower sound insulation frame and an energy-saving transformer, damping recessed seats are arranged on the both sides of the bottom of the inner cavity of the lower sound insulation frame, and the energy-saving transformer is located in the inner part of the lower sound insulation frame, and belongs to the technical field of transformers. The noise-reducing energy-saving environment-friendly transformer is characterized in that rectangular pull openings are arranged on the surface, the rear part and the both sides of the lower sound insulation frame, first positioning plates and second positioning plates are arranged on the inner sides of the rectangular pull openings respectively, and tooth blocks are arranged on the first positioning plates and the second positioning plates. After the energy-saving transformer is installed, the second spring is used to make the buffer block always adhere to the energy-saving transformer, so that the impact sound of the energy-saving transformer is reduced. In addition, the first positioning plate and the second positioning plate are always used to push the buffer block to adhere to the energy-saving transformer by the second spring when the energy-saving transformer vibrates and a gap is generated between the energy-saving transformer and the buffer block.

The utility model discloses a slewing mechanism, belongs to the technical field of metal pipe processing machines, and solves the problem that an existing slewing mechanism is high in noise. According to the technical scheme for solving the problem, the device mainly comprises a base, a transmission box arranged on the base, a power transmission mechanism which is arranged on the transmission box and comprises a power input shaft and a power output shaft, a chuck which is arranged on the power output shaft in a sliding mode and a clamping jaw which is arranged on the chuck in a sliding mode. The chuck is provided with a plurality of sliding grooves in the circumferential direction of the power input shaft, the clamping jaws can be inserted into the sliding grooves, a hollowed-out portion is arranged between every two adjacent sliding grooves, and the groove wall of each sliding groove has a certain thickness. The noise reduction device is mainly used for effectively reducing noise.

The utility model discloses a car door outer handle structure, a car door and a car, which comprises a control rod arranged on a car door outer handle seat assembly support, the control rod is in rotary limit contact with a car door outer handle handle assembly, and a car door outer handle base buffer block is arranged in an upper hole position of the car door outer handle seat assembly support. The car door outer handle base buffer block is located between the control rod and the car door outer handle base assembly support, and the front end of the control rod can make contact with the car door outer handle base buffer block. According to the utility model, the control rod is matched with the car door outer handle base buffer block for use, so that the rigid impact between the car door outer handle handle assembly and the car door outer handle base assembly bracket is avoided when a car door is opened, the impact sound is reduced, the sound quality of opening the door is improved, and the service life of the car door outer handle base assembly is prolonged at the same time.

This application relates to the field of high-voltage equipment safety technology, and in particular to an interlocking device for a high-voltage switchgear. The device includes a protective cover, a first rotating plate, a second rotating plate, a third rotating plate, and a linkage rod, all installed on the back of the high-voltage switchgear door. The first rotating plate is driven by a rotating column, and the second and third rotating plates rotate synchronously with the first rotating plate via the linkage rod. Each rotating plate is connected to a connecting rod and a locking pin. The rotation of the rotating plate drives the locking pins to extend or retract synchronously, achieving multi-point locking and unlocking of the door and door frame. The device also includes a telescopic assembly with a controller linked to the high-voltage switchgear's electrical circuit. This controller automatically controls the extension and retraction of the locking column based on the high-voltage switchgear's energized state, achieving forced locking during energization and automatic unlocking during power failure. This application simplifies the operation process, has a stable and durable structure, and effectively improves the operational safety and maintenance convenience of the high-voltage switchgear.

The invention relates to a steering engine speed reduction transmission system and method based on a linear gear. The transmission system comprises a shell assembly, a driving motor, an output shaft and a speed reduction mechanism. The speed reducing mechanism is arranged in the shell assembly and is configured to transmit the output torque of the driving motor to the output shaft; the speed reducing mechanism comprises at least one level of linear gear pair, and the linear gear pair is formed by meshing a driving linear gear and a driven linear gear; and the driving line gear and the driven line gear are respectively generated by a preset space curve and a conjugate curve thereof, and form point contact pure rolling in the meshing transmission process. Through cooperation of all the mechanisms, the single-stage large-transmission-ratio design is achieved through the small tooth number by means of the characteristic that a linear gear is free of undercutting limitation. Compared with a steering engine adopting an involute gear, the friction loss is reduced, the vibration noise is reduced, the structure compactness is improved, and the steering engine is suitable for micro steering engines, robot joints, precise executing mechanisms and other scenes.

The invention discloses a bidirectional superhigh pressure supercharger with a self-protection device, and relates to the technical field of hydraulic system pressure cylinders. Comprising a piston, an internal magnetic ring, a guide ring, an annular seal, a surface magnetic ring, a low-pressure cylinder, a low-pressure cylinder connecting screw, a magnetic shoe, a magnetic shoe fixing block, a magnetic shoe connecting screw, a magnetic shoe fixing block fixing screw, a high-pressure cylinder, a piston rod, a high-pressure seal, a high-pressure flange, a high-pressure screw, dovetail magnetic steel, a dovetail fixer and a low-pressure flange. The piston is suspended in the low-pressure cylinder according to the principle that like poles of the magnets repel each other, meanwhile, abrasion of piston sealing, piston guiding and the like caused by the self-adjustment of repulsive force of the magnets is prevented, the piston and the low-pressure cylinder are effectively protected, and the cylinder scoring phenomenon is prevented; repulsion between the piston and the low-pressure flange is achieved according to the principle that like poles of the magnets repel, the phenomenon that the piston impacts the low-pressure flange is avoided, impact noise is effectively reduced, finally, the repulsion force between the piston and the low-pressure flange can be adjusted by changing the thickness of the magnetic shoe fixing block, buffering force under different pressures is adjusted, and the buffering effect is good. And the noise is reduced on the basis of protecting the equipment.

The utility model provides a kind of engine cooling system, including engine, air inlet cover, air duct and heat exchanger, air duct is arranged between air inlet cover and heat exchanger, air duct is respectively communicated with the cold air inlet end of air inlet cover and heat exchanger, one end of engine is provided with fan, fan is set in air duct, the heat dissipation port of engine is communicated with the heat exchange air inlet of heat exchanger, at least one air guide channel and at least two first sound attenuation components are provided in air duct, first sound attenuation component is provided on the both sides of air guide channel, first sound attenuation component includes first air deflector and first sound attenuation cotton, first cavity is provided in first air deflector, a plurality of first perforations are set on the surface of first air deflector, first perforation is communicated with first cavity, and first sound attenuation cotton is set in first cavity;The utility model has the advantages of simple structure, high cooling efficiency and low noise.

The present application relates to a kind of crankshaft units, aero-engine and aircraft, belong to aerospace technology field, when flexible disc is directly connected with starter, the problem that the rotation moment of flexible disc is big, the gear of starter is easy to impact with starting gear ring at initial meshing moment, bring strong vibration and damage starting gear ring is solved.The present application includes crankshaft and flexible disc;Flexible disc is set to one end of crankshaft;Flexible disc includes disc body and starting gear ring being set to the edge of disc body along circumference;Starting gear ring is used to mesh with the gear of starter;Wherein, starting gear ring includes multiple sections being distributed along circumference, adjacent section can relatively move.The present application reduces the impact and vibration generated when the gear of starter is meshed with starting gear ring.