29results about How to "Realize axial limit" patented technology

The invention relates to the field of LED display screen installation and splicing, and discloses an arc-shaped lock capable of adjusting an LED display screen box gap, the arc-shaped lock comprises a first lock seat and a second lock seat, the inner side of the first lock seat is in sliding connection with a first lock cylinder, the inner side of the second lock seat is in sliding connection with a second lock cylinder, the middle of the first lock cylinder is provided with a locking assembly, and the locking assembly is arranged on the inner side of the second lock seat. A fixing assembly is fixedly installed on the side face of the first lock cylinder, the locking assembly comprises a clamping column, the clamping column is arranged in the middle of the first lock cylinder and the middle of the second lock cylinder, a sliding groove is formed in the clamping column, and a pin is slidably connected into the sliding groove. The clamping blocks are opened to be clamped into the annular groove in the second lock cylinder, and internal buckling and axial limiting of the two lock cylinders are achieved. And in cooperation with a screwing structure of the nut and the external thread of the clamping column, continuous axial pressing force can be applied to the surface of the lock cylinder, and the flatness of the splicing face of the LED display screen and the stability of the overall structure are ensured.

The utility model relates to pen type ignition coil technical field, and disclose a pen type ignition coil shielding shell, including car engine shell, the car engine shell inside plug -in has shielding shell body, shielding shell body inside plug -in has pen type ignition coil body, shielding shell body periphery is provided with mounting mechanism, shielding shell body periphery bottom is provided with limit mechanism, the mounting mechanism includes hollow frame, the hollow frame fixedly connected in shielding shell body left and right sides, the hollow frame inboard fixedly connected with fixed link. Spring pushes and drives sliding board, connecting rod and limit board linkage through elasticity, makes the inclined plate close -fit plug -in in the jack of pen type ignition coil body, forms radial fixed, when disassembling, only need to pull the pull plate to drive the inclined plate to separate from the jack, removes the radial restraint to the ignition coil, cooperates the loosening operation of bolt, can complete the disassembly of shielding shell and pen type ignition coil body quickly.

The application provides a quick detachable agricultural machinery transmission shaft, and belongs to the technical field of transmission shafts, which solves the problems of inconvenient replacement and disassembly of the existing agricultural machinery transmission shaft and the lack of protection function. The quick detachable agricultural machinery transmission shaft comprises a mounting block, protection mechanisms are symmetrically arranged on the two sides of the mounting block, a transmission shaft body is slidably arranged in the mounting block, an axial limiting mechanism is arranged on the mounting block, a fixing block is arranged in the protection mechanism, symmetrically distributed threaded pins are arranged on the protection mechanism, rotating handles are fixed to the ends of the threaded pins, a clamping groove and a avoiding groove are arranged on the fixing block, a hinged seat is arranged on the protection mechanism, a cross shaft is hinged to the hinged seat, and a connecting ring is arranged at the end of the cross shaft. The application can quickly and conveniently disassemble the agricultural machinery transmission shaft, prevent dust and soil from entering the device during the operation of the agricultural machinery, protect the agricultural machinery transmission shaft, and adjust the protection mechanism according to the length of the agricultural machinery transmission shaft, thereby improving the protection capability.

The invention provides an extendable nerve intervention guide wire, and relates to the technical field of medical guide wires. A one-way extension cylinder is aligned with a clamping head at the tail end of a main guide wire through an extension groove in the outer wall of the one-way extension cylinder, and is pushed in in the axial direction, so that the clamping head enters the extension groove; the inclined end face of the inclined elastic piece faces the far end of the continuous guide wire. When the guide wire needs to be lengthened, a doctor pulls the continuous guide wire outwards, at the moment, the continuous guide wire drives the one-way lengthening barrel to move towards the telecentric end relative to the main guide wire, the clamping head relatively slides towards the proximal end along the lengthening groove, and the inclined elastic piece is flattened and allowed to pass in a sliding mode. If the continuous guide wire is trying to be pushed inwards in the reverse direction, the tip of the inclined elastic piece can be clamped into the groove in the side face of the clamping head, reverse movement of the inclined elastic piece is prevented, and mechanical one-way locking is formed. A doctor is allowed to gradually push out the main guide wire from the interior of the continuous guide wire during an operation, the guide wire is extended, the extended part is prevented from accidentally retracting, and the operation length is kept stable.

The utility model relates to the technical field of electric wire laying, and disclose a kind of electric power cable core stranded wire laying device, comprising: base, the upper end one side of base is equipped with lifting mechanism, the lifting end of lifting mechanism is equipped with side frame, the outside one side of side frame is equipped with second driving motor, and the output end of second driving motor is located inside the side frame and is equipped with driving roller;Guide slot, open in the inside upper end both sides of side frame, the inside sliding installation of guide slot has guide block, and driving roller is rotatably installed between the guide block, and the upper end of guide block is equipped with first return spring;Telescopic side rod, set in the outside one side of side frame, the rear end of telescopic side rod is equipped with ring shell.The utility model lifting adjustment adapts to different height, elastic compression prevents cable deviation, blocking ring prevents loose and moves, quick-release structure simplifies cutting tool replacement, improves laying adaptability, precision and construction efficiency.

The utility model provides a welding-free supporting column retainer and a bearing. The welding-free supporting column retainer comprises a supporting column, an annular retainer cover and an annular retainer seat, the supporting column comprises a central part, a cover connecting part and a seat connecting part; the central part is sleeved with a hollow roller, the cover connecting part is connected with an annular retainer cover, and the seat connecting part is connected with an annular retainer seat; the annular retainer cover is provided with a plurality of insertion holes matched with the cover connecting part, one end, far away from the central part, of each insertion hole is provided with an annular retainer cover groove, the cover connecting part is provided with an annular groove, the annular retainer cover groove is matched with the annular groove, and an annular gasket is arranged in a space formed by the annular retainer cover groove and the annular groove; welding is not needed in the sleeving process of the supporting column holder; a traditional welding process is replaced by a pure mechanical structure of taper thread connection and elastic gasket and step limiting, and the industrial problems that the welding quality is uncontrollable and the efficiency is low are solved.

This utility model belongs to the field of sock knitting technology, and specifically relates to a sock-feeding assembly and a sock-feeding device using the same, which solves the problem of inconvenient disassembly and assembly of the sock-feeding tube and the lifting seat. The sock-feeding device of this application includes a main shell, within which the sock-feeding assembly is housed. The lifting seat is connected to a screw-nut lifting unit. A main guide rod and a secondary guide rod are provided between the screw-nut lifting unit and the sock-feeding tube. The lifting seat has an axially penetrating guide hole and a side-open guide groove. The main guide rod is slidably connected to the guide hole, and the secondary guide rod is slidably connected to the guide groove. The sock-feeding assembly includes a lifting seat, and the sock-feeding tube is radially limited and connected to the lifting seat. At least one limiting groove is provided on the sock-feeding tube. The lifting seat has a locking body that cooperates with the limiting groove. The locking body can extend into the limiting groove to prevent axial movement of the sock-feeding tube. A locking body movable positioning mechanism is provided between the locking body and the lifting seat. This achieves the effect of quick disassembly and assembly of the sock-feeding tube and the lifting seat.

The utility model provides a handheld rotary cultivator. The handheld rotary cultivator comprises a machine shell, a transmission assembly, a transmission shaft, a handle, a housing and a driving motor. The transmission shaft transversely penetrates through the bottom of the machine shell and is rotationally connected with the machine shell, the transmission assembly is connected into the machine shell, the transmission shaft is in transmission connection with the output end of the transmission assembly, and the cutter head assemblies are fixed to the two ends of the transmission shaft. The housing is fixed at the lower end of the handle; the driving motor is fixed in the housing; the lower end of the housing is detachably connected with the upper end of the machine shell, a first transmission part is coaxially fixed to an output shaft of the driving motor, the input end of the transmission assembly is in transmission connection with a second transmission part, and the second transmission part is detachably in transmission connection with the first transmission part. According to the utility model, the housing and the housing can be split, so that the packaging volume of the handheld rotary cultivator can be reduced, namely, the packaging and transportation cost of the handheld rotary cultivator can be reduced.

The utility model provides a sealing end cover with a circumferential expansion and contraction matching connection structure, which comprises a main body shielding cover component, a switching positioning component, an axial limiting component, an axial matching connection component, an auxiliary shielding cover component and an expansion and contraction matching connection component, and the design of an embedding connection ring groove of the sealing end cover enables the outer wall of a static ring to be embedded into the embedding connection ring groove. Therefore, the main body barrel shell is fixedly connected with the static ring, the stability of the whole structure is enhanced, the static ring can be axially limited through the design of the limiting notch and the sealing caulking groove, the joint face of the adapter convex ring and the static ring is sealed, and the sealing performance is improved; the end cover can be jacked and pressed through the axial jacking and pressing mechanism due to the matching of the matching ring groove and the axial jacking and pressing mechanism, so that the application of axial pressure and the sealing of the sealing ring are realized, the stable performance of the sealing element can be kept under various working conditions, and the sealing element has higher reliability and longer service life in practical application.

The utility model discloses a folding bicycle locking structure, including first frame (2) and second frame (3), both can be folded to each other. Structure is provided with a telescopic locking piece (1), has the buckle slot (102) on it, can buckle with the locking lever (103) on the frame after folding is completed, thereby will two frames keep in the folding state. The locking piece (1) further is provided with safety device (104), is used for locking the extension length of telescopic spare and limiting its axial degree of freedom in locking lever (103). Through this structure, does not need additional extrusion or accurate alignment in the folding process, and the telescopic action can buckle and install, and the operation is convenient. The safety device passes through the locking and spacing cooperation, effectively prevents the locking from being loose because of vibration or impact, guarantees the stability and security under the folding state, promotes the use reliability of folding bicycle.

This invention relates to the field of controllers, specifically an electronic controller, comprising a housing, within which an energy storage element is disposed; the energy storage element is connected to the housing via a mounting unit; the mounting unit includes an anti-detachment unit and / or a limiting unit; the anti-detachment unit prevents the energy storage element from detaching from the housing; the limiting unit prevents the energy storage element from moving within the housing; this invention, through the installation unit, improves the stability and accuracy of the energy storage element's installation within the housing, while also facilitating the installation of the energy storage element; through the combined use of the anti-detachment unit and the limiting unit, the opposing blocking mechanism in the anti-detachment unit applies a backward pressing force to the columnar energy storage element; thereby achieving the fixed stability of the columnar energy storage element; the limiting unit provides axial limiting for the columnar energy storage element, preventing its movement within the housing.

The utility model discloses a motor upper casing, which comprises an upper casing and a support fixedly arranged at the top of the upper casing, a circular through hole is arranged at the center of the top wall of the upper casing, a blind hole position for a motor rotating shaft to insert is arranged on the support right above the circular through hole, the blind hole position and the circular through hole are concentrically arranged, and the top surface of the blind hole position is a plane. The utility model also discloses a motor comprising the motor upper casing. The blind hole position is arranged on the support right above the upper shell, one end of the motor rotating shaft is inserted into the blind hole position, and the top face of the blind hole position can abut against the end face of the motor rotating shaft, so that axial limiting of the motor rotating shaft is achieved, and a traditional spindle radial fixing mode is replaced. The motor rotating shaft and the top surface of the blind hole position are fixed in a shaft end axial contact manner, and the arc-shaped end surface of the motor rotating shaft and the top surface of the blind hole position are in point contact, so that the friction force is greatly reduced, and the improved motor has the advantages of low noise, low running current, less heat and low vibration.

The utility model relates to a detachable V-cone flow meter for a test, which comprises a measuring tube provided with a positive pressure tapping tube and a negative pressure tapping tube; the supporting pipe is arranged corresponding to the negative pressure taking pipe; the negative pressure pipe is connected with the supporting pipe; the cone is arranged on the negative pressure pipe in a sleeving manner; the supporting and positioning assembly is used for supporting the cone; the locking component is used for being in locking fit with the negative pressure pipe, and the locking component is in abutting fit with the supporting and positioning assembly so as to limit the cone in the axial direction of the measuring pipe. By adopting the technical means shown in the application, in the test process, different cones can be conveniently disassembled and replaced through the locking part for performance test, after the test is completed, the finally used cone is selected, and the cone can be used for a long time by welding the supporting column with the inner wall of the measuring tube. According to the detachable V-cone flowmeter for the test, the manufacturing cost in the test process is effectively reduced.

The utility model relates to the technical field of cleaning for cable production, and discloses an ultrasonic cleaning device for cable production, which comprises a cleaning bin, a motor I is fixedly connected to the right side of the front end of the cleaning bin, a waterproof shell is fixedly connected to the inner wall of the right end of the cleaning bin, and a motor II is fixedly connected to the inner wall of the waterproof shell. The driving end of the second motor is connected with a cleaning table through a transmission set, the driving end of the first motor is fixedly connected with a reciprocating lead screw, the outer wall of the reciprocating lead screw is connected with a moving shell through a reciprocating set, the left end of the cleaning table is rotationally connected with an adjusting ring, and the inner wall of the adjusting ring is connected with a transmission lead screw through a gear set; the outer wall of the transmission lead screw is rotationally connected with a connecting table. According to the cable cleaning device, synergistic interaction of mechanical brushing, ultrasonic cavitation and fluid impact is achieved, the cleaning uniformity and the stubborn stain removal rate are remarkably improved, self-adaptive clamping pressure is formed on a cable through the arc-shaped elastic contact surface of the two supporting plates, and the surface is prevented from being damaged by rigid extrusion.

This utility model discloses a connection structure for precast floor slabs, belonging to the field of precast floor slab connection technology. It includes a precast beam and a precast wall panel body. The precast beam has a slot and a circular hole inside, and the slot and the circular hole are connected. A movable plate is slidably connected inside the slot. A first spring is fixedly connected to one side of the movable plate, and the other end of the first spring is fixedly connected to the inner wall of the circular hole. An insert block is fixedly connected to the side of the precast wall panel body near the precast beam. Through the cooperation of the insert block, slot, circular hole, first spring, and limiting mechanism, when the insert block is inserted into the slot, the limiting insert plate will be pushed into the limiting groove by a second spring, achieving axial limiting of the insert block and effectively preventing the insert block from detaching. This achieves initial fixing of the precast beam and the precast wall panel body. Further fixing with pre-embedded bolts significantly improves the overall connection strength and reliability.

The utility model discloses a kind of safety protection device and syringe for injection, applied to syringe equipment field, safety protection device for injection includes needle guard, first limiting part and second limiting part are equipped on needle guard, the side wall of needle guard is also equipped with embracing ring, embracing ring is elastic structure;When needle guard is in initial state or protective state to shield needle head located on needle cylinder, embracing ring and the circumferential portion of recess portion abut along the radial direction of needle cylinder, first limiting part and limiting platform are connected along the axial direction of needle cylinder;When needle guard is in recovery state to release needle head, second limiting part and limiting platform are connected along the axial direction of needle cylinder, embracing ring and the rear end side wall of needle cylinder abut.The safety protection device for injection provided by the utility model can prevent needle guard from being irreversibly deflected due to jolt impact, avoid interference jam caused by deflection of needle guard when syringe is loaded and unloaded, and can ensure smooth movement of needle guard from initial state to recovery state and then to protective state.

The utility model provides a hub reduction structure which comprises a knuckle shell, a hub, a planetary transmission assembly, a gear ring seat and an inner gear ring, and the hub is connected with the knuckle shell through a first bearing assembly; the planetary transmission assembly comprises a planet carrier fixed to the end of the hub and a planet wheel arranged on the planet carrier. The gear ring seat is connected with the steering knuckle shell in a sleeving manner through a spline; the inner gear ring is arranged in the hub and meshed with the planet wheel, the inner gear ring is connected with the gear ring seat through a spline, a first step part which is concave outwards is arranged on the side, close to the steering knuckle shell, of an inner ring of the inner gear ring, and the gear ring seat is arranged in the first step part and abuts against the step face of the end of the first step part. The side, away from the steering knuckle shell, of the inner gear ring abuts against the planet carrier, axial limiting of the inner gear ring is achieved, parts are saved, assembling is easy, cost is reduced, and meanwhile the overall reliability is improved.

The utility model discloses a leakproof flange sealing connection device, which belongs to the technical field of flange connection and comprises a left flange and a right flange, the left flange and the right flange are respectively provided with a plurality of first bolt holes, first bolts sequentially penetrate through the right flange and the left flange and are screwed through first nuts, and the first nuts are pressed on the end face of the left flange. A head nut of the first bolt is pressed on the end face of the right flange; a plurality of second screw holes are formed in the side wall of the left flange, the axes of the second screw holes are perpendicular to the axes of the first bolt holes, the second screw holes and the first bolt holes are arranged in a one-to-one correspondence mode and communicated, second screws are connected to the second screw holes in a threaded mode, and positioning holes are formed in screws of the first bolts. After the first bolt is screwed down through the first nut, the positioning hole and the second screw hole are coaxial, and the second screw penetrates through the positioning hole. According to the utility model, the sealing connection of the left flange and the right flange has double protection effects of transverse and longitudinal combination, and the connection sealing performance is greatly improved.

The present invention relates to the field of ice making technology, and in particular to an ice making device and a refrigeration device. The ice making device comprises a bracket, on which a plurality of ice making boxes are arranged; an operating member, which is installed on the bracket; a connecting member, which is connected between the operating member and the plurality of ice making boxes so that the operating member drives the plurality of ice making boxes to move; the connecting member is provided with a loosening hole and a limiting hole which correspond to the operating member and the plurality of ice making boxes one by one and are interconnected; the connecting member is suitable for switching between a loosening position and a limiting position; in the loosening position, the operating member and the plurality of ice making boxes are respectively connected to the loosening hole and are suitable for being disengaged from the loosening hole; in the limiting position, the operating member and the plurality of ice making boxes are respectively connected to the limiting hole. The ice making device can realize linkage deicing of the plurality of ice making boxes and the operating member through a connecting member, thereby improving the deicing efficiency. At the same time, it can also improve the disassembly and assembly efficiency of the operating member and the ice making box, making it convenient for users to clean the ice making box.

The application relates to the technical field of molds, and particularly discloses a glass bottle encapsulating mold and a product thereof. The glass bottle encapsulating mold comprises a bottle mouth positioning structure arranged on a lower mold plate, the bottle mouth positioning structure comprises a positioning insert arranged on the lower mold plate and a high-temperature-resistant deformable sleeve block sleeved outside the positioning insert, the inner side wall of the deformable sleeve block is provided with a thread structure matched with a thread part of a glass bottle mouth, the top of the positioning insert is provided with an annular taper part, and the annular taper part comprises a buffer part used for abutting against the end part of the glass bottle mouth. The glass bottle encapsulating mold can realize full encapsulation of a glass bottle body, has good positioning effect, and effectively reduces the influence of injection impact force on the glass bottle.

The utility model discloses a circuit breaker pressure spring pin pressing and riveting tool, and belongs to the technical field of electrical equipment manufacturing, the circuit breaker pressure spring pin pressing and riveting tool comprises a rack, a positioning assembly, a limiting assembly and a pressing and riveting assembly, the positioning assembly is installed on one side of the rack, and a positioning groove is formed in the positioning assembly; the limiting assembly is arranged opposite to the positioning assembly and used for clamping and driving the insulation pull rod to move in the direction close to or away from the rivet pressing assembly, and the rivet pressing assembly is used for riveting the edge of the pressure spring pin. The positioning assembly, the limiting assembly and the press riveting assembly are used in cooperation, automatic and accurate riveting of the pressure spring pin can be achieved, the riveting efficiency of the pressure spring pin is improved, the consistency of the knocking angle and position of the pressure spring pin is guaranteed, the situation that the center of the pressure spring pin is expanded due to stress, and use is affected is effectively avoided, and the production efficiency is improved. The action reliability and the operation stability of opening and closing of the circuit breaker are improved; according to the utility model, the qualified rate of opening and closing parameters of the circuit breaker can be effectively improved, batch reworking is reduced, and the production efficiency is improved.

This utility model relates to the field of medical device technology, specifically to a dental curved handpiece. The dental curved handpiece includes a head assembly, a transmission assembly, a liner assembly, a screw, and a curved handle. The transmission assembly and the liner assembly are embedded in the curved handle at a preset bending angle. The bottom end of the liner assembly abuts against the curved handle, and the top end of the liner assembly abuts against the transmission assembly. One end of the head assembly engages with the transmission assembly for transmission, and the other end extends beyond the top end of the head assembly. A limiting groove is formed on the outer wall of the head assembly. One end of the screw abuts against the limiting groove, and the other end is embedded in the bottom end of the curved handle. The screw is threadedly connected to the transmission assembly, and their axes are parallel. The angle between the screw and the head assembly is a preset bending angle, allowing the top end of the screw to extend into the limiting groove. By abutting against the inner wall of the limiting groove and / or the corner of the groove bottom, the screw axially limits the head assembly, preventing it from dislodging from the curved handle during treatment.

The invention discloses a crank arm limiting structure, and relates to the related technical field of liquid crystal glass substrate forming equipment, the crank arm limiting structure comprises a crank arm, a positioning sleeve and a crank arm rotating shaft, the crank arm rotating shaft is sleeved with the crank arm and the positioning sleeve, the positioning sleeve is installed on the crank arm rotating shaft through a locknut, the positioning sleeve is sleeved with a copper pad and a limiting clamp, and the limiting clamp is installed on the positioning sleeve. A limiting ring groove is formed in the outer side face of the positioning sleeve, the limiting clamp comprises a limiting frame, and the limiting frame is of a U-shaped limiting frame body structure. The screw is used for driving the wedge-shaped block to move so that the positioning sleeve can be clamped by the clamp, and axial limiting in a limited space is achieved; by means of the combination of the positioning sleeve and the limiting clamp, the limiting clamp can be normally removed after the positioning sleeve is clamped in a threaded mode, then normal disassembly and assembly of the crank arm are achieved, the clamping position can be selected according to the actual production requirement, then the adjustable limiting position within the design margin is achieved, and safety, flexibility and practicability are achieved.

This invention provides a turbine disk overspeed test structure and its installation method, relating to the field of aero-engine testing technology. The turbine disk overspeed test structure includes an overspeed rupture disk, a counterweight, and a sealing ring. The overspeed rupture disk includes an interconnected test section and a connecting section, with the connecting section located on one axial side of the test section. The counterweight is engaged with the test section and is located radially outward of the test section. The sealing ring has an interconnected connecting end and a limiting end, with the limiting end located on one axial side of the connecting end and connected to the counterweight to limit the axial position of the counterweight. The connecting end is fixedly connected to the connecting section to fix the sealing ring relative to the overspeed rupture disk. This turbine disk overspeed test structure eliminates the need for an open retaining ring, using the sealing ring to axially limit the counterweight, thereby avoiding abnormal interruptions to the overspeed test due to deformation of the open retaining ring and improving the operational safety of the turbine disk overspeed test structure.

The utility model belongs to the field of engineering machinery relates to a kind of quick lifting thimble, including thimble, thimble connecting sleeve, thimble guide cylinder and stopper, wherein one end of the thimble is threadedly connected with the thimble connecting sleeve, the thimble connecting sleeve is axially slidably installed in the thimble guide cylinder, and limiting rack along axial arrangement is equipped on the thimble connecting sleeve;Opening is equipped on the side of the thimble guide cylinder close to the limiting rack, and movable stopper is arranged at the opening, and the stopper can be clamped in the limiting rack by moving position, or separated from the limiting rack, to limit the axial movement of the thimble connecting sleeve, or make the thimble connecting sleeve freely axially move.The utility model ingeniously converts the ineffective stroke of thimble into quick lifting action, combined with gravity falling mechanism, simplifies the spin-in spin-out process of traditional thimble.

The invention relates to the technical field of flatness detection equipment, in particular to bicycle hub end face flatness detection equipment and method, and the equipment comprises a detection table, a detection mechanism and a continuous conveying mechanism. The detection mechanism comprises a base, a detection disc, a movable insertion structure, a detection device, a driving disc and a pressing driver, a mounting seat is integrally formed at the upper end of the detection disc, an insertion hole is formed in the middle of the mounting seat in the axis direction, and an insertion groove corresponding to a spline on the hub is formed in the side wall of the insertion hole; the detection device is used for detecting the axial run-out of the detection disc; the continuous conveying mechanism comprises a continuous conveying frame and a plurality of clamping structures, the continuous conveying frame is used for driving the multiple clamping structures to pass through the upper portion of the mounting base in sequence, and the clamping structures are used for clamping bicycle hubs; the detection mechanism and the continuous conveying mechanism are arranged, and continuous detection of the bicycle hub end face cutting flatness is achieved.

The utility model discloses a protective cover and developing box assembly, the developing box includes: developing casing, is used to accommodate developer, developing roller is used to bear developer, and the rotation axis direction of developing roller is the first direction, end cover is located developing casing one end, and support is located the other end. The protective cover includes protective cover main part, first installation part and second installation part. First installation part includes first main part and joint, and joint cooperates with end cover, and second installation part is connected with protective cover main part, has the recess or is closed structure, and forms the joint or the cladding type connection with support. Along the first direction, first installation part and second installation part are opposite and located the both ends of protective cover main part, realize double -end fixed, prevent loose and fall off, and promote developing roller protection reliability.

The utility model provides a hub reduction structure which comprises a knuckle shell, a hub, a planetary transmission assembly, an inner gear ring and a gear ring seat, the knuckle shell comprises a connecting part and a housing part, and the connecting part is provided with a second step part protruding outwards in the radial direction; a limiting step part is arranged on the side, close to the housing part, in the hub. The planetary transmission assembly comprises a planet carrier fixed to the end of the hub, and a mounting groove is formed between the planet carrier and the limiting step part. The inner gear ring is arranged in the mounting groove, and a first step part which is sunken outwards in the radial direction is arranged on the side, close to the housing part, of the inner ring of the inner gear ring. One side of the gear ring seat is connected with the steering knuckle shell in a sleeved mode through a spline and abuts against the second step portion through a spacer bush, and the other side of the gear ring seat is arranged in the first step portion, connected with the inner gear ring through a spline and abuts against the step face of the end of the first step portion, so that axial limiting of the gear ring seat is achieved, assembling is easy, parts are saved, and cost is reduced. And the overall reliability is also improved while the cost is reduced.