137results about How to "With limit function" patented technology

The inVention belongs to the technical field of noVel cigarettes, and particularly relates to a cigarette structure of a heating non-combustible cigarette. The heating non-combustible cigarette is composed of a cylinder hollow coiling block, a cleaning spacer sleeVe arranged at the front end of the coiling block, and a smoking product section and a cooling filtering section which are sequentiallyarranged inside the coiling block. By arranging the cleaning spacer sleeVe, a user can insert a heating body into a cigarette, no cut tobacco can drop out, meanwhile, small parts in smoking products cannot fall into a heater in the heating process, and cleanness in the heater is ensured.

The invention provides a numerical display type radial drilling machine, comprising a spindle speed regulating and spindle feeding speed regulating system, a spindle feeding mechanism, a spindle and balance mechanism, a spindle positive / negative rotation and variable-speed control mechanism, a rocker arm and clamping mechanism, an upright and rocker arm lifting mechanism, a hydraulic and cooling system, a testing system, a numerical display control system and the like; the upright and rocker arm lifting mechanism is mounted on a base; the rocker arm and clamping mechanism is mounted on the upright and rocker arm lifting mechanism; the numerical display control system is mounted on the upright and rocker arm lifting mechanism; the spindle speed regulating and spindle feeding speed regulating system is mounted on the rocker arm and clamping mechanism; the spindle feeding mechanism, the spindle and balance mechanism, the spindle positive / negative rotation and variable-speed control mechanism, and the hydraulic and cooling system are mounted on the spindle speed regulating and spindle feeding speed regulating system. According to the numerical display type radial drilling machine, stepless speed changing of a spindle can be realized without shutdown; graphic and numerical display can be realized at working positions; a die wall clamping device of a guide rail and a spindle limiting structure are sensitive and reliable; in short, the numerical display type radial drilling machine is applicable to machining industries.

The inVention belongs to the technical field of noVel cigarettes, and particularly relates to a cigarette structure of a heating non-combustible cigarette. The heating non-combustible cigarette is composed of a cylinder hollow coiling block and a cigarette front section, a cigarette middle section and a cigarette back section which are sequentially arranged inside the coiling block, and the diameters of the cigarette front section, the cigarette middle section and the cigarette back section are all equal to the inner diameter of the coiling block. By forming multiple sheet heating body insertion grooVes, a consumer can conVeniently insert sheet heating bodies into cigarettes. When the structure of the multiple sheet heating body insertion grooVes is adopted for heating, the surplus sheet type heating body insertion grooVes and suction resistance regulating air holes can jointly achieVe the air guiding effect, and the insertion grooVes can also replace the suction resistance regulatingair holes to directly achieVe the air guiding effect.

The invention discloses a vehicle door hinge structure integrated with a limiter, which comprises a rotary hinge and a fixed seat, wherein the rotary hinge is hinged with the fixed seat through a hinge rotating shaft; the rotary hinge is provided with a screw hole for fixing a vehicle door inner plate; the fixed seat is provided with a screw hole for fixing a vehicle body framework; the vehicle door hinge structure also comprises a limiting baffle block arranged on the rotary hinge and a torsion bar arranged on the fixed seat; one end of the limiting baffle block is fixed to the rotary hinge; the limiting baffle block is hinged to the hinge rotating shaft and is provided with a group of baffle concave arcs; one end of the torsion bar is fixed on the fixed seat, while the other end is a free end; and the free end of the torsion bar is contacted with the concave arcs on the limiting baffle block. The vehicle door hinge structure is integrated with the vehicle door limiter, has simple structure and small occupied space and is convenient to arrange.

The invention discloses a square high-load air spring. The square high-load air spring comprises a sac body, an upper snap ring, a lower snap ring, an upper cover plate, a lower cover plate, an upper limiting part, a lower limiting part and a plurality of connecting pieces, wherein the sac body is formed by vulcanizing a sac body rubber, a framework layer, an upper seam allowance steel ring and a lower seam allowance steel ring together; the upper cover plate and the lower cover plate are provided with grooves which are matched with the shapes of the upper seam allowance steel ring and the lower seam allowance steel ring of the sac body; the sac body is assembled on the upper and lower cover plates through the grooves; the upper seam allowance steel ring of the sac body is tightly pressed on the upper cover plate by the upper snap ring, and the lower seam allowance steel ring of the sac body is tightly pressed on the lower cover plate by the lower snap ring; the upper and lower snap rings are connected and fastened to the upper and lower cover plates through the connecting pieces; the upper and lower limiting parts are positioned in the sac body, the upper limiting part is connected to the upper cover plate through the connecting pieces, and the lower limiting part is connected to the lower cover plate through the connecting pieces; and an air hole and mounting holes are formed on the upper cover plate.

The invention discloses a coupling device, a cavity filter and communication radio frequency equipment. The coupling device comprises a signal transmission main rod and a coupling body which is used for acquiring a signal of the signal transmission main rod, wherein the coupling body is connected to a printed circuit board in parallel to the signal transmission main rod. The coupling device is characterized in that the coupling body comprises a coupling outer conductor which is connected to the printed circuit board, and a coupling inner conductor which is arranged in the coupling outer conductor, wherein one end of the coupling inner conductor is positioned in a through hole of the printed circuit board; the coupling inner conductor comprises a threaded part and is in threaded fit with the coupling outer conductor through the threaded part; an elastic fixing block is arranged between the coupling outer conductor and the coupling inner conductor; and the coupling inner conductor is in interference fit with the elastic fixing block and is fixed in the through hole of the coupling outer conductor. The coupling device can be conveniently installed, has limiting and self-locking functions, is free of short-circuit, and is high in safety.

The invention relates to a series four-way ball valve group. The series four-way ball valve group comprises a first four-way ball valve and a second four-way ball valve; a first valve element is arranged in a valve cavity of the first four-way ball valve, a second valve element is arranged in a valve cavity of the second four-way ball valve, and the first valve element and the second valve element are fixedly connected and synchronously rotate under the effect of a drive mechanism to achieve synchronous switching of the flow direction of fluid; the first valve element and the second valve element are fixedly connected and can rotate at the same time under the effect of the drive mechanism, through the structure, the flow directions of the fluid in the first four-way ball valve and the second four-way ball valve are switched at the same time, consistency of actions of the first valve element and the second valve element is ensured, and the interlocking function of the first valve element and the second valve element is achieved.

The invention relates to an on-site calibration method of a marine fiber bragg grating strain sensor. The method comprises the following steps of establishing a data preparing an upper computer,establishing the database on the upper computer, and setting electric communication between a simulated to-be-tested board and the database; mounting the simulated to-be-tested board: performing surface bonding on the simulated to-be-tested board and the fiber bragg grating strain sensor to form an equivalent strain; installing a fiber bragg grating demodulation instrument: connecting the fiber bragg grating strain sensor with the fiber bragg grating demodulation instrument; installing a simulated vibration analysis device; carrying out simulation analysis: obtaining the strain of the fiber bragg grating strain sensor for simulating the natural frequency vibration state of the to-be-tested board, determining the strain as calibration source data Z1, and storing the calibration source dataZ1 in a database; starting a fiber bragg grating demodulation instrument program to obtain actual strain data Z2 of the fiber bragg grating strain sensor; and carrying out comparison and calibration:displaying the data obtained in the steps S5 and S6 on a display screen of the upper computer, and performing comparison and calibration. The method is good in calibration effect and high in calibration precision.

The invention provides a shield segment lining connector structure with a limiting function to achieve simultaneous limiting of a longitudinal slot and an annular slot during segment assembly. The quality of a formed tunnel is improved, the mounting difficulty of connecting bolts is reduced, and mounting efficiency is effectively improved. The shield segment lining connector structure comprises a preorder splicing segment with a bolt front hole channel and a postorder splicing segment with a bolt rear hole channel, and a connecting bolt penetrates through the corresponding bolt front hole channel and bolt rear hole channel to connect the preorder splicing segment and the postorder splicing segment into a whole. A limiting mortise is arranged at the position, located on an end opening of the bolt front hole channel on a splicing joint, of the preorder splicing segment, and the rear portion of a limiting tenon with a through hole allowing the connecting bolt to penetrate is mounted in the limiting mortise. A limiting tenon groove is formed in the position, located on an end opening of the bolt rear hole channel on a splicing joint, of the postorder splicing segment, the length of the limiting tenon groove extends in the splicing sliding direction, and the front portion of the limiting tenon is inserted into the limiting tenon groove. The splicing joints comprise an annular splicing joint and a longitudinal splicing joint.

The invention discloses a vibration isolator outer sleeve which comprises a sleeve body integrally formed. The cross section of the sleeve body is of a non-equilateral polygon cylindrical structure. T-shaped support holes are formed in the side walls, corresponding to at lest two relatively-long edges, of the sleeve body. Each T-shaped support hole comprises a horizontal hole extending towards two sides and a vertical hole extending downwards from the middle of the horizontal hole. A jacking hole is formed in the side wall, above each support hole, of the sleeve body. The outside of the sleeve body is provided with a boss extending outwardly from each support hole and the corresponding jacking hole. Each boss recesses towards one side of the center of the sleeve body to form a pit. The sleeve is simple in structure, integrally formed, good in mechanical performance, long in service life, convenient to operate and good in limit effect, no special limit parts are needed, and a vibration isolator can be rotated into the sleeve from two directions and limited by the T-shaped support holes.

The invention discloses a glass clamp. The glass clamp comprises a clamp main body which is provided with a clamping groove used for clamping glass, and a hanging assembly which is positioned at the top of the clamp main body and is used for connecting an external structure; the clamp main body comprises a front glass clamp and a rear glass clamp which are connected with each other and define the clamping groove, and a connecting piece which is used for fixing the front glass clamp and the rear glass clamp; a first rack and a second rack are respectively arranged on the opposite sides of the front glass clamp and the rear glass clamp, and the first rack and the second rack are in vertical engagement connection. In the scheme of the invention, the first rack and the second rack are fastened and buckled by locking a glass connecting piece, so that the purpose of clamping the glass is achieved; a hole does not require to be formed in the glass, so that the original internal stress balance of the glass is prevented from being disturbed; moreover, a limiting effect is achieved through a tooth engagement structure, and the situation that the glass is broken because of stress concentration caused by overexerting when screw threads of the glass clamp are locked is prevented.

The invention discloses an earthquake-isolation energy dissipator for an ultra-high-voltage converter transformer. The earthquake-isolation energy dissipator comprises a plurality of earthquake-isolation supports, steel plates and thin rubbers which are arranged horizontally are arranged on the earthquake-isolation supports from top to bottom at intervals, and central holes are arranged at centers of the earthquake-isolation supports and provided with lead cores inside. The earthquake-isolation energy dissipator is characterized by further being provided with a squared foundation valve plate composed by steel beams, an upper connecting plate and a lower connecting plate, wherein the plurality of earthquake-isolation supports are installed at steel beam nodes of the foundation valve plate, the upper connecting plate and the lower connecting plate are parallel, and the upper and lower surfaces of the earthquake-isolation supports are connected with the centers of the upper connecting plate and the lower connecting plate respectively. According to the earthquake-isolation energy dissipator, the stability is guaranteed, simultaneously, the horizontal stiffness is small, the earthquake-isolation damping effect can be improved, soft limiting and anti-falling functions are provided, the safety of the earthquake-isolation energy dissipator under the action of earthquakes can be guaranteed, when the earthquake-isolation fails, a certain damping effect is also provided, and the safety function is provided in case of failure. The earthquake-isolation energy dissipator is low in construction cost, simple in construction and provided with good social benefits.

The invention belongs to the technical field of engineering buildings, and particularly relates to a cement laying device for building engineering. Aiming at the problem that a general bricklaying robot cannot well lay cement during use, so that hollow possibly exists inside the cement after the cement is laid, and engineering quality problems are caused, the following scheme is presented now. According to the scheme, the cement laying device comprises a stand column and a main body located at the top end of a wall body, wherein a third fixing plate is welded to the middle of the main body, apressing plate is welded to the bottom end of the third fixing plate, a spring is welded to the top end of the third fixing plate, and a rotating plate is welded to the top end of the spring. According to the cement laying device, the device encounters a gap between bricks in the travelling process to form jounce and up-down shaking, the rotating plate is formed to rotate up and down through the spring, the inclined rotating plate enables the cement to quickly slide on the wall body, the cement can drive a rotating body to rotate through pressing blocks in the sliding process, and the pressingblocks press the cement falling on the wall body in the rotating process, so that air in the cement is discharged.

The invention discloses a prefabricated composite energy-dissipated steel beam and column structure with multi-stage damping and secondary amplification of displacement. The prefabricated composite energy-dissipated steel beam and column structure comprises a prefabricated steel beam, a prefabricated steel column, energy dissipation walls, notches, door and window holes, an upper connecting plate,a lower connecting plate, a vertical type moving displacement support, a displacement amplification rod, a L-shaped fixed support, a U-shaped sliding rod, lug plates, a gear rotating shaft, bolt pins, bolts, front and rear cover plates, fan-shaped notches, column type bearing blocks, limiting rotating plates, an annular groove, shear-resistant keys, shearing blocks, an outer circular ring, low yield point steel and an inner limiting ring. The prefabricated composite energy-dissipated steel beam and column structure is clear in energy dissipation mechanism, realizes multistage control energy dissipation and gives full play to the functions of each energy dissipation part at different stages through shear deformation of the shearing blocks and the yield energy dissipation of the low yield point steel. Furthermore, the horizontal displacement between layers of a structure is subjected to secondary amplification, the efficiency of energy dissipation is improved, the damage and failure ofa main body of a steel structure can be effectively reduced, and replacement is convenient after the earthquake or after the damage.

The invention relates to a replacement device, in particular to an oil filter replacement device. The oil filter replacement device is used for quickly unscrewing and stably fixing an oil filter. Theoil filter replacement device comprises a mounting cover, a first connecting rod, a fixing component and a power component, wherein the mounting cover is used for being mounted on a whole device body;the first connecting rod is welded to the mounting cover; the fixing component is mounted between the first connecting rod and the mounting cover; and the power component is mounted on the first connecting rod and supplies power in a rotating mode. According to the oil filter replacement device, through cooperation of a thread and a nut, the oil filter can be quickly fixed and then dismantled; through cooperation of a rhombic rod and a rhombic hole, the oil filter can be quickly fixed and then dismantled; through cooperation of sliding rods and plastic balls, the oil filter can be dismantledand fixed more stably; and limiting blocks have a limiting function.

A rocker arm and clamping mechanism of a digital display type radial drilling machine comprises a rocker arm, a pushing shaft, a piston, a cam, a support, an oil cylinder, an oil cylinder head, a clamping pressing plate, a pull rod, a lever and a hinging shaft. The rocker arm is provided with the pull rod and connected with the clamping pressing plate, the lever is fixed to the rocker arm through the hinging shaft, and the rocker arm is provided with the pushing shaft and the support; the oil cylinder is mounted on the support, the piston and the cam are mounted in the oil cylinder, and the oil cylinder head is mounted on the oil cylinder. According to the working principle, the rocker arm is mounted on a guide rail type outer rectangular post A and moves up and down along the guide rail type outer rectangular post A, and the guiding precision of the rocker arm and the guide rail type outer rectangular post A is guaranteed. According to the rocker arm and clamping mechanism, stepless speed changing of a spindle can be achieved under the non-halt condition, and working positions can be displayed through figures and numbers; the guiding precision of a guide rail is high, the spindle has a limiting function and is flexible and reliable, and a control system is advanced; the rocker arm and clamping mechanism is simple and reasonable in structure, convenient and quick to operate and high in working efficiency and can be applied to the machining industry.

The invention relates to a four-way ball valve. The four-way ball valve comprises a valve body and a valve plug, wherein the valve body is provided with four fluid inlet and outlet channels, the valve plug is located in an inner cavity of the valve body, a valve seat component is arranged in each fluid inlet and outlet channel, and comprises a pre-fastening spring junk ring, a valve seat support barrel and an annular valve seat seal ring which are coaxial with the fluid inlet and outlet channel and are sequentially distributed along the axis, the annular valve seat seal ring is in sealed fit with the valve plug, the outer side surface of each valve seat support barrel is in sealed fit with the inner wall surface of the corresponding fluid inlet and outlet channel, a circular groove used for clamping the valve seat seal ring is arranged on the end surface, close to the inner cavity of the valve body, of the valve seat support barrel, a plurality of pre-fastening springs are arranged between the end surfaces of each pre-fastening spring junk ring and the corresponding valve seat support barrel, a limit part is mounted on the inner wall of each fluid inlet and outlet channel, and the end surface, far from the inner cavity of the valve body, of each pre-fastening spring junk ring is abutted against the corresponding limit part. The valve seat component greatly improves the sealing reliability of the valve, and the installation, the displacement and the maintenance of the valve seat component are very convenient.

The invention discloses a pushing mechanism simple and convenient to mount and reliable in limiting for a multipath magnetic latching relay. The pushing mechanism includes a pushing block, an armature part and at least two moving spring parts; the armature part and the moving spring parts are matched with the pushing block in a clamping manner; the pushing block is provided with a first clamping groove matched with the armature part and at least two second clamping grooves matched with the moving spring parts; a first limiting part is arranged in the first clamping groove of the pushing block, so as to stop bidirectional movement of the pushing block in a thickness direction with cooperation of the armature part; only one of the at least two second clamping grooves of the pushing block is provided with a second limiting part, the moving spring parts are provided with third clamping grooves, and the second limiting part of the pushing block is matched with the third clamping grooves of the moving spring parts, so as to stop bidirectional movement of the pushing block in a width direction. Through structural improvement of the pushing block and the moving spring parts, and by utilization of matching of the pushing block with the moving spring parts and the armature part, the pushing mechanism provided by the invention realizes a stable limiting function and has the characteristics of being simple to assemble and high in production efficiency.

The invention discloses a vibration isolation and reduction bracket for cable structures, comprising a support member (1), a vibration isolator (3), a hydraulic vibration reducer (6), a spring (7), a regulating nut (5), and a connecting pedestal (4). An adjustable combined vibration reducer (B) is composed of the spring (7), the hydraulic vibration reducer (6) inside the spring and the regulating nut (5), wherein the spring (7) provides support force, stiffness and reset ability, the regulating nut (5) regulates the length of the spring (7) to ensure that there is no tensile stress at a support member the root (A) in the balanced position, and the hydraulic vibration reducer (6) plays a role in in-plane buffer, displacement control, energy consumption and vibration reduction. The vibration isolator (3) produces shear deformation and consumes energy, and can reduce out-of-plane longitudinal vibration caused by action of the support member (1). By adopting the vibration isolation and reduction bracket for cable structures, fracture or fatigue damage of the support member root (A) caused by in-plane and out-of-plane three-direction vibration is solved, the redundancy of cable structures is enhanced, and the safety and using performance of a supported structure (2) are improved.

The invention discloses a ground well lifting mechanism, which comprises a wheel disc with a wheel disc groove, a box body with a cover plate and a worm and gear mechanism, a worm shaft, a gear shaft, a driving gear, a gear wheel, a bearing clip, a lifting wheel disc shaft and a clutch which are arranged in the box body, wherein the worm and gear mechanism is connected with the clutch through the worm shaft; the clutch is connected with the gear shaft through the bearing clip; the driving gear is arranged on the gear shaft; the gear wheel is meshed with the driving gear; the lifting wheel disc shaft is arranged on the gear wheel; the wheel disc is arranged on the lifting wheel disc shaft and positioned outside the box body; an Archimedes cam is also arranged outside the box body to be meshed with the gear shaft; and a motor is connected with the worm and gear mechanism. In the invention, the component members of the lifting mechanism are combined in the box body according to functions, the members are used effectively, the cost is reduced, the installation area is small, quick falling and limiting functions are realized, the safety of the mechanism is improved, and the safety of relates person and materials are ensured.

The invention discloses an electronic hydraulic door closer which comprises an external mechanism, a door stop solenoid valve and a rocker arm. The external mechanism comprises a stop plate, a mount plate and a stop plate limiter. The rocker arm of the door closer comprises a rocker arm body and a regulating arm connected in sequence; a rotation shaft and the stop plate with limit angle capable of being regulated rotationally are arranged on the rocker arm; the stop plate is provided with a limit notch, the limit notch is meshed with a steel ball in the rocker arm body, and the steel ball is abutted by a spring. As an oil circuit and an end cap of the door closer are connected into a whole, the integral structural design of the door closer is much more reasonable and compacter, the structure size of the door closer is reduced, maintenance and changing of the door closer are facilitated, and the door closer has higher specificity.

The invention relates to a foldable three-wheel transportation tool with an automatic reset steering component. The foldable three-wheel transportation tool with the automatic reset steering component comprises a handle bar (15), a saddle (2), pedals (5), rear wheels (11), a front frame (4-1), a rear frame (4-2) and the steering component (16) connected between the front frame (4-1) and the rear frame (4-2), wherein the steering component (16) comprises a rotating shaft (16-9), a bearing seat (16-7), a shaft fixing piece (16-10), two deep groove ball bearings, an elastic steel piece (16-15) and two fixing piece L-shaped elastic steel piece fixing pieces (16-1, 16-13), the rotating shaft (9) is fixedly connected with the bearing seat (16-7) through the deep groove ball bearings, the deep groove ball bearings (16-5) are installed in the bearing seat (16-7), and the shaft fixing piece (16-10) is installed on the rotating shaft in a located mode; the elastic steel piece (16-15) penetrates through the rotating shaft (16-9). The foldable three-wheel transportation tool with the automatic reset steering component has the advantages that the radius of a turning circle is small, the side turning is not prone to occurring, the stability is good, and the foldable effect is achieved.

The invention discloses an automatic strapping and packing machine and a strapping and packing technology thereof. The automatic strapping and packing machine comprises a transit detection platform, alinkage feeding mechanical arm, sheet stacking platforms, sheet picking and rotating mechanisms, belting and strapping mechanism, bundle picking and blanking mechanical arms and a stock box; the transit detection platform is arranged on a rack, the linkage feeding mechanical arm is arranged on the front side of the transit detection platform, and two sets of stock suction assemblies are arrangedon the linkage feeding mechanical arm at intervals; the sheet stacking platforms are arranged on the right side of the transit detection platform at intervals; the sheet picking and rotating mechanisms are arranged on the rear sides of the sheet stacking platforms, and stacked glass sheets in the sheet stacking platform are clamped and picked out by the sheet picking and rotating mechanisms and rotate to the vertical direction; the belting and strapping mechanisms are arranged on the side portions of the sheet picking and rotating mechanisms; the bundle picking and blanking mechanical arms are arranged on the right sides of the sheet picking and rotating mechanisms. The automatic strapping and packing machine effectively reduces membrane material collision between the adjacent glass sheets and membrane material collision between the glass sheets and external objects, effectively achieves concentrated storage of the glass sheets, and greatly improves the storage efficiency of the glasssheets.

The invention discloses a production device for preparing tic whiskers, and belongs to the technical field of drying devices, an upper cover is arranged at one end of a drying tank, a heating plate and a limiting block are fixedly connected to the inner wall of the drying tank, a supporting rod is fixedly connected to one surface of the limiting block through a screw rod, and a water collecting box is fixedly connected to one end of the supporting rod; the center of the bottom of the water collecting box is fixedly sleeved with a sealing bearing, the center of the sealing bearing is fixedly sleeved with a shaft rod, and the other end face of the shaft rod is fixedly connected with a rotating rake through a screw. According to the production device for preparing the tic whiskers, the horn-shaped filter screen convenient to assemble and disassemble has a vibration function, the solid-liquid separation efficiency is improved, the discharging speed of crystal whiskers can be increased, thearranged water collecting box has the function of automatically collecting liquid, the liquid can be rapidly guided out of the drying tank, the temperature in the drying tank is prevented from beingaffected by the liquid, the drying speed of the crystal whiskers is increased, and then production efficiency is improved.

The invention belongs to the technical field of pipe fitting plastics, and particularly relates to a hot melting connector capable of being quickly positioned, and a water dissolving core injection molding process thereof. The hot melting connector comprises a connector body provided with at least one installing end, wherein an installing site is arranged on an inner wall of the connector body; aguiding core is arranged on the installing site; an outer side wall of the guiding core is a guiding surface; a hot melting guiding part adaptive to the wall thickness of a hot melting pipe is formedbetween the guiding surface and an inner wall of the installing end; a guiding opening is formed in the outer end of the hot melting guiding part. The guiding core provided by the invention has the following effects that a, during heating, the guiding core can be prevented from being inclinedly or one-sidedly heated; b, during hot melting, a pipeline and the connector keep in a straight line, so that an annular fusion welding surface is uniformly fusion-welded, and the occurrence of the phenomenon of one-sided fusion welding is avoided.The injection molding process provided by the invention isapplied to the plastic industry and is mainly aimed at the plastic products which have complex inner cavity larger than the outer port and are not suitable for the core demoulding treatment. The plastic products produced by the injection molding process can integrally form a complex inner cavity, the core demoulding is not needed, the manufacturing cost is low and the water dissolving core can beeasily removed by water washing.

The invention discloses a limiting device for a hopper car bottom door opening and closing mechanism, and belongs to the technical field of freight vehicles. The limiting device specifically comprisesan upper transmission shaft, the upper transmission shaft drives a bottom door to be opened or closed through rotation, the limiting device comprises a limiting swing arm fixedly connected with a swing block, and a limiting mechanism which comprises a deflector rod device and a positioning block, and the deflector rod device drives the positioning block to longitudinally move along the guide structure so that the positioning block moves to different positioning gears; the swing block of the upper transmission shaft drives the limiting swing arm to rotate to the positioning blocks of differentgears so that the rotating angle of the upper transmission shaft is limited, and the opening state of the bottom door is controlled. The opening angle and the ballast unloading flow of a ballast unloading bottom door are achieved by controlling the rotating angle of the transmission shaft, and the functions of mistaken rotation prevention, multi-gear ballast unloading flow control and limiting when the bottom door is located at the full-open position are achieved.