37results about How to "Crawl quickly" patented technology

The invention discloses a bearing retainer ring installation device. The bearing retainer ring installation device comprises a machine frame and a control system. The machine frame sequentially comprises a conveying disc, a conveying station, a shifting fork transferring station, a bearing containing station, a first assembly station, a turning station, a second assembly station and a discharging station. The bearing retainer ring installation device has the advantages that the installation device is suitable for installing retainer rings of irregular structures, installation is accurate and firm, and two end faces of a bearing can be assembled at the same time.

The invention discloses a pull-type picking, kneading, bundling and bagging machine for straw feed. The pull-type picking, kneading, bundling and bagging machine comprises an integral rack, a picking, kneading and transporting device, a straw smashing filling bin, a straw compacting, bundling and bagging device and a powder transmission system. The innovative technologies such as the picking kneading and transporting device being front-arranged to suspend and hydraulically lift, deep tearing, kneading and smashing processing conducted on coarse hard section head and dense surface of corn straw, straw smashing three-direction hydraulic strong compaction and bundling to transport, straw compaction bundling, automatic packing after manual bagging are adopted, and combination processes of picking and smashing, compacting and bundling, bagging and packing are conducted on corn straw in the field. And the pull-type picking, kneading, bundling and bagging machine for the straw feed has the advantages that the technology is advanced, the structure is reasonable, the production efficiency is high, and the working quality is good. Straw feed compaction bales made by the machine has good sealing environment, microbial fermentation action can also occur in a natural condition, the slaking degree is improved, the nutrition ingredient is increased, and the palatability, the grazing rate and the digestion and absorption rate are improved when cattle and sheep are fed.

The invention discloses a combined calibration method between a three-dimensional laser radar and a mechanical arm of a mobile operation robot, and belongs to the technical fields of autonomous targetrecognition, grabbing and human-computer cooperation of the mobile operation robot. According to the method, a common square paperboard is used as a reference object in a robot calibration process, three-dimensional point cloud acquisition is carried out through a three-dimensional laser radar loaded through the robot, the acquired point cloud is preprocessed, the square paperboard clamped through the tail end of the mechanical arm is recognized, a coordinate value of the mechanical arm in the three-dimensional laser radar is obtained, and the coordinate value of the mechanical arm in a controller is acquired through the mechanical arm controller; and the position of the mechanical arm is repeatedly adjusted for N times (N is larger than or equal to 8 ) and the corresponding coordinate values of the mechanical arm are obtained; and finally, the coordinate conversion relation between the coordinate of the mechanical arm in the three-dimensional laser radar and the coordinate of the mechanical arm controller through using a least square method is solved.

The invention provides a URL (uniform resource locator) purifying method including the steps of matching an original URL to a domain name of a domain name set capable of being purified, positioning to a corresponding URL template set according to the domain name successful in matching, matching the original URL to a regular expression of a URL template of the URL template set, judging whether the template with the regular expression successful in matching contains command words or not, if so, then processing the URL according to the command words and going to the step of outputting a new URL purified, otherwise, returning to the original URL, and finally outputting the new URL purified. The invention further provides a URL purifying device. Whether the URLs of various forms are crawled or not can be judged after the URLs are purified; if crawled, then the URLs are not have to be crawled again; therefore, effective-webpage crawling capacity of clawers is improved remarkably and various resources are saved.

The invention discloses a trail-type straw collecting, smashing and bundling machine. The machine is composed of a complete machine frame, a collecting, smashing and conveying device, a smashed straw filling device, a straw compacting and bundling device and a power transmission system. The machine well overcomes the technical problems like pre-hydraulic lifting of the collecting, smashing and conveying device, connecting and conveying of vertical and horizontal auger rollers, intermittent and fast and smooth filler dragging, piston-type strong compressing of straw, artificial tying and bundling of stringing driven by hydraulic pressure, adjustment of bundling bale density by clamping a side wall, and removing and top squeezing of straw bundling bales by adopting a plurality of innovative technologies in the aspects of layout and arrangement of overall structure, integration and conformity of functional parts for operation, matching and selection of transmission power, etc. According to the invention, the machine has the outstanding features of advanced technology, reasonable structure, high production efficiency, good operation quality, wide application range, etc.; and the machine is suitable for combined operation of collecting, picking, smashing, conveying, compacting and bundling of straws of crops like standing or spread-or-strip windrowing corns, wheat, beans, sorghum, cotton and oilseed rapes.

The invention relates to a mouse experiment animal multifunction operation bed which is characterized in that the operation bed comprises an upper body plate 1 and a lower body plate 2. The periphery of the operation bed is provided with a fixed bolt 3 and a fixed bolt with a hole 4; the middle of the upper body plate is provided with an arch cover 5; the side wall of the arch cover 5 is opened with a side hole 6; the end of the arch cover 5 is provided with a bolt 7 with a hole for fixing teeth; the end part and the tail part of the arch cover 5 are respectively provided with an end cover 8 and an end cap 9 which are matched with the arch cover 5; the lower body plate 2 is provided with a blocking bolt 11 which is corresponding to the bolt 7 with a hole for fixing teeth and is provided with an anesthesia box which is matched with an end cap 8. The operation bed fully use the habit of the mouse experiment animal which likes drilling holes and can quickly realize grabbing, anaesthetizing, fixing and operation and the like on the experiment animal by simple operations, thus improving the safety and effectiveness of the animal experiment.

The invention discloses a mechanical arm dense object temperature priority grabbing method based on deep reinforcement learning. The method comprises the following steps of S1, constructing a mechanical arm working space, and constructing a real-time state; S2, preprocessing state information; S3, carrying out forward transmission on the preprocessed information through a Q network to obtain a corresponding Q value; S4, instructing a mechanical arm to act according to the Q value and an epsilon-greedy strategy, and obtaining rewards through a reward function; S5, continuously updating the weight through a target Q network to realize training of the Q network; and S6, recording related data in the training process and a model finally formed after training to obtain an optimal grabbing strategy of the mechanical arm. The method has the advantages that the method is specifically applied to the grabbing scenes where objects have irregular shapes and are densely stacked and temperature factors need to be preferentially considered; the mechanical arm action is designed according to the deep reinforcement learning algorithm, so that the grabbing performance of the mechanical arm is improved; and an infrared image is introduced, so that the mechanical arm has the capacity of preferentially grabbing objects with higher temperature.

The invention discloses a Chinese medicinal liniment for treating burn and scalding. In traditional Chinese medicine, burn and scalding are caused because skin is harmed directly by extraneous harm such as fire toxin, thermal toxin and the like. Therefore, according to the Chinese medicinal liniment, Chinese medicines such as golden thread, common anemarrhena rhizome, figwort root, heartleaf houttuynia herb, pariphyllin, notoginseng root, red paeony, gypsum, catechu and calamine which have the effects of clearing heat, purging pathogenic fire, cooling blood, promoting blood circulation, relieving pain and promoting tissue regeneration are put into a proper amount of sesame oil to be soaked for 48 hours and decocted over slow fire until the medicine is withered and yellow in color, decoction dregs are removed and drained, yellow wax is added so as to prepare paste, and the paste is put into a sterile container for later use. After 158 patients are treated, 52 patients who suffer from first-degree burn are cured completely within one week; 39 patients who suffer from superficial second-degree burn are cured within 2 to 3 weeks; 67 patients who suffer from deep second-degree burn arecured after 4 weeks; and the total cure rate is 100 percent, so the Chinese medicinal liniment is worth of clinical popularization and application.

The invention discloses a flexible arm capable of being driven to extend, belongs to the field of flexible arms, and aims to solve the problem of complicated control flow in a traditional pneumatic flexible clamping hand. The flexible arm capable of being driven to extend comprises a first fixed plate, a second fixed plate, a first elastic airbag, a second elastic airbag, a first air transmissionpipe, a second air transmission pipe, a connecting spring and a clamping hand module; a first through hole is formed in the first fixed plate; and a second through hole is formed in the second fixed plate. The flexible arm can effectively solve the problem of complicated control structure in a traditional flexible robot, is skillful in concept, simple in structure, low in cost, excellent in performance, reasonable in design, high in adaptability, higher in application value and better in application prospect, and deserves large-scale popularization and application. Through actual application,the flexible clamping hand can meet the clamping demands of objects with different shapes, and can realize lifting and grabbing of the objects with a higher weight than the flexible clamping hand by 10-15 times.

The invention discloses a cascade type multi-finger cross manipulator which comprises an arm rod, a fixing base, paws, a pen type electric push rod and auxiliary grabbing structures, wherein the arm rod is fixedly connected to the top of the fixing base, the paws comprise the left claw and the right claw, and the left claw and the right claw are oppositely arranged on the left side and the right side of the bottom of the fixing base correspondingly; the left claw and the right claw are provided with a left finger and a right finger respectively, the left finger and the right finger are arranged in a staggered mode, the pen type electric push rod is arranged in the arm rod, the top end of the pen type electric push rod is fixed to the top of the arm rod, and the bottom end of the pen type electric push rod is connected with the top of the left claw and the top of the right claw. The auxiliary grabbing structures are oppositely arranged at the bottom of the left finger and the bottom of the right finger respectively. The paw are opened and closed through pushing and pulling of the pen type electric push rod, a large-diameter object is grabbed through a main body part of the paw, and a small-diameter object is reversely grabbed through the two auxiliary grabbing structures.

The invention discloses a feeding mechanical hand. The feeding mechanical hand structurally comprises a rotary column, a mechanical arm, a base and a storage cabinet. The bottom of the rotary column is movably clamped to the upper wall of the base, the mechanical arm is cooperatively mounted on one side of the rotary column, and the storage cabinet is arranged on the front side of the base. The feeding mechanical hand has the beneficial effects that a positioning block drives a telescopic rod to stretch out to the needed length, a suction block is located on the upper surface of a ceramic tile, a through pipe sucks air upwards, a suction plate is pulled upwards, a sucker tightly sucks the surface of the ceramic tile, the adsorption force for the ceramic tile is improved through suction grooves in the bottom of the suction plate, dust and water on the ceramic tile are wiped away through brushes and sponge blocks at the bottoms of cleaning plates, the situation that as water exists on the surface of the ceramic tile, the ceramic tile and the sucker slip, and the ceramic tile falls and is smashed into pieces in the feeding process is avoided, and grabbing of the mechanical hand for the ceramic tile is improved.

The invention provides an electronic skin glove device applied to a robot hand. The electronic skin glove device comprises a simulated skin glove made of a flexible waterproof material, a sensor component used for obtaining a sensing signal and an electric connection interface used for leading an internal signal transmission line into the simulated skin glove to be connected with the sensor component, wherein the sensor component is arranged at the inner side of the simulated skin glove, and the electric connection interface is formed in the simulated skin glove. By the adoption of the electronic skin glove device applied to the robot hand, the robot hand can be sleeved with the expanded simulated skin glove with certain elasticity, and connection is conducted through the electric connection interface, so that the device is convenient and fast to mount and dismount; and meanwhile, the material, temperature, physical properties, chemical properties and the like of an operation object ofa robot can be sensed more finely through the arranged sensor component, and then the operation performance of the robot hand is improved.

The invention relates to a sand mould clamping mechanism. The sand mould clamping mechanism comprises a cross beam, a rotating shaft rotatably mounted on the cross beam, clamping arms slidingly mounted on the two ends of the cross beam and gripper assemblies fixedly mounted on the bottom ends of the clamping arms. Each gripper assembly comprises a fixed base, multiple large grippers and multiple small grippers, and the large grippers and the small grippers are arranged on the fixed base in a spaced manner. The fixed bases are rotatably mounted on the inner side walls of the corresponding clamping arms, the large grippers are used for being clamped on lifting handles of large sand moulds, the small grippers are used for protruding and extending into concave structures of small sand moulds,and the sand mould clamping mechanism can be suitable for grabbing of sand moulds of different sizes and different weights, and the efficiency of producing sand moulds can be effectively improved.

The invention relates to an uncapping hoisting device, which comprises a driving block, wherein the driving block is arranged in a hoisting base and is further horizontally slid with the bottom end ofthe inner wall of the hoisting base; the side wall of the driving block is provided with a vertical groove; the extended end surface of one side of the bottom end of the driving block is provided with a right-trapezoid lug boss a; one end of a swing link is rotationally connected with a rotating shaft; the other end of the swing link is connected with the driving block and the vertical groove ina sliding meaner respectively; the lower part of the rotating shaft is provided with a gear; a lifting block is arranged in the hoisting base and is further slid up and down with the inner wall of thehoisting base; a right-trapezoid lug boss b is connected with an oblique angle of the right-trapezoid lug boss a in the sliding manner; a first rack passes through the lifting block and is further rotationally connected with the gear at the lower part of the rotating shaft. The device to which the invention relates is used for realizing solving the problem that the location of a manipulator of anuncapping mechanism is inaccurate, is simpler in structure, integrates grabbing and hoisting and is used for decreasing the risk of a collision caused as a grabbing mechanism is arranged on a centralaxis.

The invention discloses high-precision grabbing equipment based on electrical control. According to the high-precision grabbing equipment, a plurality of sets of clamping driving mechanisms are arranged, simultaneous clamping of a plurality of block workpieces can be achieved. Precision grabbing mechanisms comprise fixed clamping plates and movable clamping jaws, each movable clamping jaws is arranged opposite to each fixed clamping plate, each movable clamping jaw is mounted on a driving clamping plate through a posture adjusting driving mechanism, the driving clamping plate is driven by eachclamping driving mechanism to enable the driving clamping plate to drive each movable clamping jaw to move relative to each fixed clamping plate, and when grabbing is carried out, the position of anobject is finely adjusted by using the posture adjusting driving mechanism, so that the accuracy of grabbing is guaranteed. Each movable clamping jaw comprises a clamping jaw body and four clamping jaw arms integrally arranged on the clamping jaw body, the center of the clamping jaw body is connected to an output end of the posture adjusting driving mechanism, the clamping arms are used for clamping the object, the position fine adjustment of the object is achieved by utilizing the posture adjusting rotation of the clamping jaw arms before clamping, and high-precision grabbing is achieved.

The invention discloses a pull-type picking, kneading, bundling and bagging machine for straw feed. The pull-type picking, kneading, bundling and bagging machine comprises an integral rack, a picking, kneading and transporting device, a straw smashing filling bin, a straw compacting, bundling and bagging device and a powder transmission system. The innovative technologies such as the picking kneading and transporting device being front-arranged to suspend and hydraulically lift, deep tearing, kneading and smashing processing conducted on coarse hard section head and dense surface of corn straw, straw smashing three-direction hydraulic strong compaction and bundling to transport, straw compaction bundling, automatic packing after manual bagging are adopted, and combination processes of picking and smashing, compacting and bundling, bagging and packing are conducted on corn straw in the field. And the pull-type picking, kneading, bundling and bagging machine for the straw feed has the advantages that the technology is advanced, the structure is reasonable, the production efficiency is high, and the working quality is good. Straw feed compaction bales made by the machine has good sealing environment, microbial fermentation action can also occur in a natural condition, the slaking degree is improved, the nutrition ingredient is increased, and the palatability, the grazing rate and the digestion and absorption rate are improved when cattle and sheep are fed.

The low-headroom hoisting device and the hoisting system provided by the present invention relate to the technical field of engineering and construction. The low-headroom hoisting device includes: a casing, a spreader, a traveling unit and a hoisting unit; the traveling unit includes driving the casing The hoisting unit includes a hoisting motor that drives the spreader to lift and lower, and the hoisting motor and the traveling motor are respectively arranged on both sides of the running track. In the low-headroom hoisting device provided by the present invention, the hoisting motor and the traveling motor are respectively arranged on both sides of the running track, which can not only greatly reduce the clearance of the whole device, but also can grab heavy objects higher. At the same time, it can also make the weight distribution of the whole device reasonable, and the center of gravity is on the center line of the running track, which has the advantages of low headroom and structural size.

The invention discloses a traditional Chinese medicine ointment for treating burn and scald. The traditional medical science believes that burn and scald are caused by direct damages on the skin from the external hurts, such as fire toxin and heat toxin. The traditional Chinese ointment provided by the invention is prepared by selecting Radix Scutellariae, hopleaf ampelopsis root-bark, Radix Arnebiae seu Lithospermi, realgar, camphor, Rheum Officinale, Salviae miltiorrhizae, stem and leaf of slender-spike Gouania, pearl, Haloragis micrantha and Buddleja lindleyana Fort.; the traditional Chinese medicine ointment has the functions of clearing heat and discharging fire, cooling and activating blood, diminishing inflammation and relieving pain, activating blood and dispersing stagnation, and removing slough and promoting the growth of tissue regeneration; furthermore, the traditional Chinese medicine ointment is capable of improving local blood circulation and histotrophic nutrition, promoting the granulation tissues to quickly grow, enabling the wound epithelial tissues to quickly centripetally crawl, and reducing the wound edges, thereby being convenient to repair, preventing scars and contracture and softening the scars as well. Through the clinical tests, the total effective ratio reaches up to 97.5%, thereby being significantly superior to a control group; and meanwhile, the average healing time of the wound is significantly shorter than that of a control group, so that the traditional Chinese medicine ointment is worthy of promotion and application in clinic.

The invention discloses a manipulator for picking up injection molded sheets, which comprises a body of the manipulator for picking up injection molded sheets composed of a base, a manipulator arm and a grabbing mechanism. The top of the base is fixedly connected to the bottom of the manipulator arm, and the left bottom of the manipulator arm is The top of the grabbing mechanism is rotatably connected, and the inside of the mechanical arm is respectively provided with a suction vacuum pump and a micro motor. The grabbing mechanism includes an upper block, and the top of the upper block is rotatably connected to the micro motor through a rotating rod. The interior of the upper bearing block is slidably connected with a touch mechanism. The present invention relates to the technical field of injection molding manipulators. This kind of manipulator for picking up injection molded pieces solves the problem that during the production process of injection molded pieces, the temperature of injection molded pieces is high, the labor intensity of manual picking is high, the efficiency is low, and it is easy to burn; when ordinary manipulators pick up, individual injection molded pieces are squeezed, causing The injection molded sheet is deformed, and it is easy to fall off during the transfer process, causing damage to the injection molded sheet.

The invention relates to a target object pose determination method and device, a storage medium and electronic equipment and aims to solve the problem of relatively low accuracy of target object posedetermination in related technologies, and the method comprises the steps of determining target coordinates of each input point in a target object according to 3D point cloud corresponding to the target object; based on a down-sampling method, generating seed points according to the target coordinates of each input point; inputting the original coordinate of each seed point into a deep neural network model to obtain a central point coordinate and an in-situ point coordinate of each seed point; and determining the 6D pose of the target object according to the central point coordinate and the in-situ point coordinate of each seed point. Accuracy of determining the pose of the target object is improved.

A visual imitation-based robotic sequence task learning method for instructing robots to imitate human actions from videos containing them. The steps are: (1) According to the input image, use the region-based mask convolutional neural network to identify the object type and mask; (2) Calculate the actual plane physical coordinates (x, y) of the object according to the mask; (3) Identify the target Atomic actions in the video; (4) convert the atomic action sequence and the recognized object type into a one-dimensional vector; (5) input the one-dimensional vector into the task planner, and output a task description vector that can guide the robot; (6) Combining the task description vector and object coordinates, the robot is controlled to complete the robot's imitation of the sequence tasks in the target video. The invention takes videos and images as input, recognizes objects and infers task sequences, and guides the robot to complete the imitation of the target video. At the same time, it has strong generalization and can still complete the imitation tasks under different environments or object types.

The invention discloses a joint calibration method between a three-dimensional laser radar and a mechanical arm of a mobile operation robot, and belongs to the technical field of autonomous target identification, grasping and human-machine cooperation of the mobile operation robot. It uses ordinary square cardboard as a reference object in the robot calibration process, collects three-dimensional point clouds through the three-dimensional laser radar carried by the robot, preprocesses the acquired point cloud, and recognizes the square cardboard held by the end of the mechanical arm. The coordinate value of the arm in the three-dimensional laser radar is obtained by the controller of the robot arm; the position of the robot arm is adjusted repeatedly N times (N≥8), and the corresponding coordinate value is obtained, and finally the least squares is used Multiplication solves the coordinate transformation relationship between the coordinates of the manipulator in the 3D lidar and its controller.

The invention discloses a method for detecting glucose in a beverage by using a composite probe based on SERS (Surface Enhanced Raman Scattering), and belongs to the field of analysis and detection. The method comprises the steps that firstly, a silver nitrate solution and a COF material are mixed, heated and incubated, after incubation is finished, a sodium citrate solution is added for reduction, and an AgNPs (at) COF substrate is obtained; adding a TMB (Tetramethylbenzidine) aqueous solution into the obtained AgNPs (at) COF substrate, and uniformly mixing to obtain a TMB-AgNPs (at) COF SERS (Surface Enhanced Raman Scattering) probe; mixing a series of glucose aqueous solutions with known concentrations with the beverage sample solution to be detected and the TMB-AgNPs (at) COF SERS probe solution to obtain a test sample solution; performing Raman detection on the test sample solution to obtain a Raman spectrum; performing linear correlation on the peak intensity attenuation rate A at the characteristic peak 1604cm <-1 > + / -5cm <-1 > and the glucose concentration of the corresponding test sample solution to obtain a detection model. According to the method, the TMB-AgNPs (at) COF is used as an SERS probe to detect the glucose in the beverage, the detection time is within 5 minutes, and the detection limit is as low as 0.094 mg / L.

The invention discloses a Chinese medicinal liniment for treating burn and scalding. In traditional Chinese medicine, burn and scalding are caused because skin is harmed directly by extraneous harm such as fire toxin, thermal toxin and the like. Therefore, according to the Chinese medicinal liniment, Chinese medicines such as golden thread, common anemarrhena rhizome, figwort root, heartleaf houttuynia herb, pariphyllin, notoginseng root, red paeony, gypsum, catechu and calamine which have the effects of clearing heat, purging pathogenic fire, cooling blood, promoting blood circulation, relieving pain and promoting tissue regeneration are put into a proper amount of sesame oil to be soaked for 48 hours and decocted over slow fire until the medicine is withered and yellow in color, decoction dregs are removed and drained, yellow wax is added so as to prepare paste, and the paste is put into a sterile container for later use. After 158 patients are treated, 52 patients who suffer from first-degree burn are cured completely within one week; 39 patients who suffer from superficial second-degree burn are cured within 2 to 3 weeks; 67 patients who suffer from deep second-degree burn arecured after 4 weeks; and the total cure rate is 100 percent, so the Chinese medicinal liniment is worth of clinical popularization and application.

The invention relates to a mouse experiment animal multifunction operation bed which is characterized in that the operation bed comprises an upper body plate 1 and a lower body plate 2. The periphery of the operation bed is provided with a fixed bolt 3 and a fixed bolt with a hole 4; the middle of the upper body plate is provided with an arch cover 5; the side wall of the arch cover 5 is opened with a side hole 6; the end of the arch cover 5 is provided with a bolt 7 with a hole for fixing teeth; the end part and the tail part of the arch cover 5 are respectively provided with an end cover 8 and an end cap 9 which are matched with the arch cover 5; the lower body plate 2 is provided with a blocking bolt 11 which is corresponding to the bolt 7 with a hole for fixing teeth and is provided with an anesthesia box which is matched with an end cap 8. The operation bed fully use the habit of the mouse experiment animal which likes drilling holes and can quickly realize grabbing, anaesthetizing, fixing and operation and the like on the experiment animal by simple operations, thus improving the safety and effectiveness of the animal experiment.

The invention discloses a trail-type straw collecting, smashing and bundling machine. The machine is composed of a complete machine frame, a collecting, smashing and conveying device, a smashed straw filling device, a straw compacting and bundling device and a power transmission system. The machine well overcomes the technical problems like pre-hydraulic lifting of the collecting, smashing and conveying device, connecting and conveying of vertical and horizontal auger rollers, intermittent and fast and smooth filler dragging, piston-type strong compressing of straw, artificial tying and bundling of stringing driven by hydraulic pressure, adjustment of bundling bale density by clamping a side wall, and removing and top squeezing of straw bundling bales by adopting a plurality of innovative technologies in the aspects of layout and arrangement of overall structure, integration and conformity of functional parts for operation, matching and selection of transmission power, etc. According to the invention, the machine has the outstanding features of advanced technology, reasonable structure, high production efficiency, good operation quality, wide application range, etc.; and the machine is suitable for combined operation of collecting, picking, smashing, conveying, compacting and bundling of straws of crops like standing or spread-or-strip windrowing corns, wheat, beans, sorghum, cotton and oilseed rapes.

The invention discloses a bearing retainer ring installation device. The bearing retainer ring installation device comprises a machine frame and a control system. The machine frame sequentially comprises a conveying disc, a conveying station, a shifting fork transferring station, a bearing containing station, a first assembly station, a turning station, a second assembly station and a discharging station. The bearing retainer ring installation device has the advantages that the installation device is suitable for installing retainer rings of irregular structures, installation is accurate and firm, and two end faces of a bearing can be assembled at the same time.