74results about How to "Low machining accuracy requirements" patented technology

This application relates to the field of conveying equipment technology, and proposes a tensioning structure and a roller motor. The tensioning structure is used to connect a driving component and a rotating component. Under the drive of the driving component, the tensioning structure can drive the rotating component to rotate around a rotation axis. The tensioning structure includes: a first connecting component, which is connected to the driving component; a limiting component, including a bottom wall and a side wall provided along the periphery of the bottom wall, with an installation groove on the side wall, and the bottom wall is detachably connected to the first connecting component so that the side wall can be sleeved on the first connecting component; and a tensioning component, which engages with the installation groove, with the side of the tensioning component opposite to the first connecting component protruding from the installation groove and abutting against the rotating component. In the above-mentioned tensioning structure, a reliable frictional force is generated between the tensioning component and the rotating component to achieve a fixed connection, thereby driving the rotating component to rotate around the rotation axis. This connection method has low requirements for the shape of the tensioning structure, reduces the requirements for processing accuracy, and solves the technical problems of existing roller and sleeve connection methods that have high processing accuracy requirements and complex disassembly and assembly.

A loader frame articulation structure, belonging to the field of engineering machinery, includes a front frame and a rear frame, connected by an articulation assembly. The articulation assembly includes an articulation shaft, which is fixedly mounted on the front frame, and the rear frame is rotatably connected to the articulation shaft. The articulation shaft includes a cylindrical portion and a truncated cone portion. The truncated cone portion is fixedly mounted on the upper end of the cylindrical portion and installed within an articulation hole in the front frame. A mounting plate is mounted on the upper end of the truncated cone portion, and the mounting plate is fixedly connected to the front frame by bolts. The cylindrical portion is rotatably connected to the rear frame, and the lower end of the cylindrical portion is connected to the articulation hole on the front frame via a bushing. The use of a conical surface fit at the loader's articulation structure significantly improves the assembly accuracy and connection strength at the articulation point, thereby solving the connection strength problem at the articulation point under extreme working conditions and the fatigue wear problem caused by the increasing use time of the loader, effectively reducing the failure rate of the loader product.

The application discloses a lower limb supine position rehabilitation aid for sports rehabilitation training, which comprises a leg fixing plate and a foot fixing plate, the surface of the leg fixing plate is provided with a sliding rail through fixed installation, the surface of the sliding rail is slidably connected with a sliding piece, the two sides of the foot fixing plate are hingedly connected with semicircular first connecting pieces through first pin shafts, the top of the first connecting piece is fixedly connected with a first pull rod, and one end of the first pull rod is hingedly connected to one side of the sliding piece through a second pin shaft. The different hole positions of the index pin locking hole on the surface of the leg fixing plate are locked and matched with each other through the index pin, the foot fixing plate and the leg fixing plate are fixed at different angles, the setting can meet the demand of the person to be rehabilitated for different angles due to the lower limb condition, and the index pin is matched with the index pin locking hole for fixing, the operation is simple and convenient, and the unlocking and locking can be quickly realized.

This utility model discloses a valve structure, comprising: a housing having a first cavity, a second cavity, a first connecting hole, a second connecting hole, and a valve port; the first connecting hole being located on the peripheral wall of the housing and communicating with the first cavity; the second connecting hole connecting the first cavity and the second cavity; and the valve port located at the end of the second cavity opposite to the first cavity; and a valve core passing through the second connecting hole, with its outer peripheral wall sealed to the inner peripheral wall of the second connecting hole. The valve core is movable along the axial direction of the housing and has a balancing flow channel and a flow port. The flow port is located on the peripheral wall of the valve core, and the balancing flow channel connects the flow port and the valve port. In a first position, the entire flow port is located on the side of the second connecting hole facing the valve port; in a second position, at least a portion of the flow port is located on the side of the second connecting hole opposite to the valve port. According to this valve structure, the requirements for valve core machining accuracy can be reduced, thus lowering production costs.

The pot cover assembly comprises a cover body and an inner cover arranged below the cover body, an exhaust hole is formed in the inner cover, the pot cover assembly further comprises an anti-blocking cover arranged on the lower side of the inner cover, the projection, facing the inner cover, of the anti-blocking cover covers the exhaust hole, a heat insulation piece is fixed to the anti-blocking cover, and the heat insulation piece is fixed to the inner cover. The heat insulation piece is provided with a connecting part and a holding part, the connecting part is used for being fixedly connected with the inner cover, and the holding part protrudes out of the outer surface of the anti-blocking cover. The anti-blocking cover is fixed to the inner cover through the heat insulation piece, and the heat insulation piece is not prone to deformation at high temperature, so that the connecting effect and stability of the heat insulation piece and the inner cover can be kept, and stable connection and position stability of the anti-blocking cover are kept. When the anti-blocking cover is disassembled, a user can grasp the holding part, protruding out of the anti-blocking cover, of the heat insulation part to disassemble the heat insulation part and the anti-blocking cover from the inner cover together, and the holding part protrudes out of the surface of the anti-blocking cover, so that the heat insulation cover is convenient to hold by the user, the temperature of the heat insulation cover is low, and the user can obtain better touch feeling.

This utility model discloses a multi-jaw hydraulic vise clamp, including a base, a clamping assembly, and a hydraulic drive cylinder. The clamping assembly includes a main body, a pull rod, multiple sliders, multiple swing arms, and multiple jaw blocks. The multiple sliders are arranged in a circumferential interval around the center of the main body. The multiple swing arms are mounted inside the main body and can swing back and forth. Each swing arm is hinged to the pull rod and driven by the pull rod to swing back and forth. Each swing arm is also hinged to a multiple slider and drives the slider to slide back and forth horizontally. By mounting multiple swing arms inside the main body and using the pull rod to drive the multiple swing arms to swing back and forth, which in turn drives the multiple sliders to slide back and forth horizontally, this design replaces the traditional structure where parts use inclined surfaces for fit. This design has lower requirements for the machining accuracy of parts, is easier to assemble, and avoids jamming. The transmission is more stable and smooth, and the clamping is more stable and reliable, bringing convenience to machining operations.

This invention relates to the field of motorsports technology, and more particularly to a transmission system for an off-road rally car and a race car equipped with the transmission system. The system includes a frame and a transmission system mounted on the frame. Wheels are mounted on the frame via a suspension system. The transmission system includes a gearbox mounted at the rear of the frame and a differential mounted at the front of the frame; the gearbox and the differential are connected by a first driveshaft positioned at the front and rear. The suspension system includes front steering knuckles located inside the two front wheels, both of which are fixed to the front side of the frame via upper and lower double wishbone suspensions. This off-road rally car has advantages such as lighter weight, more compact structure, better handling, superior passability, and higher safety. The lighter vehicle has sufficient power performance, and its low self-friction resistance during travel improves its ability to traverse uneven roads, reducing the risk of rollover and thus improving race performance.

The utility model provides a kind of valve seat sealing ring installation tool of VCR diaphragm valve, the intermediate passage is formed between the valve body and valve seat of VCR diaphragm valve, and the upper end plane of the intermediate passage is provided with sealing ring installation groove;The outside of the sealing ring installation groove is provided with stainless steel wall, and the inside of the stainless steel wall is in contact with the outer circle of sealing ring;The valve seat sealing ring installation tool includes pressing mechanism, and the pressing mechanism is cylindrical barrel, and the inside wall bottom of the pressing mechanism is provided with inclined plane and vertical surface, and the vertical surface is in contact with the outside of stainless steel wall;The outside of the stainless steel wall is provided with first step, and the first step is used to install pressing mechanism;When the pressing mechanism descends to the first step, inclined plane extrudes stainless steel wall, so that the stainless steel wall is closely attached with sealing ring.The installation tool provided by the utility model can make the deformation of the stainless steel wall outside sealing ring, so as to ensure that sealing ring and stainless steel wall are closely combined, and improve sealing performance.

This utility model relates to the field of low-voltage switchgear technology, specifically an interlocking mechanism for a movable drawer unit and the movable drawer unit itself. The interlocking mechanism includes a position interlocking mechanism, comprising a position interlocking drive plate and a movable portion position locking plate. The movable portion position locking plate is located on the back of the movable drawer unit and is fixed to the movable portion. The position interlocking drive plate is positioned by embedding a positioning element into a corresponding position positioning hole on the movable portion position locking plate. The fixed and movable portions of the movable drawer unit are interlocked through the aforementioned interlocking mechanism. The advantages are: the interlocking mechanism has complete functions, low structural cost, small space occupation, and enables unit miniaturization; the use of T-shaped sliding columns and guide rails for push-guided limiting reduces the precision requirements of sheet metal parts processing, lowers costs, solves push-up failures, controls the upward tilting of the rear of the movable portion, and also increases the internal width of the unit.

The utility model belongs to the technical field of buffers, and particularly relates to a mandrel type and piston type liquid-gas buffer, a mandrel comprises a shaft body, a shaft rod front end and a shaft rod rear end are respectively arranged on two sides of the shaft body, the shaft rod front end is connected with a mandrel seat, an inner hole is arranged on the mandrel seat, the inner hole is sleeved on the outer side of the shaft body, and the piston type liquid-gas buffer is arranged on the mandrel seat. The rear end of the shaft rod is connected with a cylinder base, the shaft body is of an equal-diameter cylindrical structure, the diameter of the cylindrical structure is equal to that of an inner hole in the mandrel seat, and an oil channel of a groove structure is arranged on the surface of the shaft body. A conical column structure is improved into an equal-diameter cylindrical structure, the diameter of the cylindrical structure is equal to that of the inner hole in the mandrel seat, and a plurality of oil liquid channels with groove structures are arranged on the shaft rod, so that the cost is relatively reduced, the buffering force can be uniformly distributed, and the buffering effect is improved. And the condition that the core shaft is stuck on the core shaft seat can be avoided when an impactor with larger kinetic energy impacts.

The utility model relates to a roller press tension adjusting assembly which comprises a swing roller and a rotating shaft, a first swing arm is arranged between the transmission end of the rotating shaft and the left end of the swing roller, a second swing arm is arranged between the non-transmission end of the rotating shaft and the right end of the swing roller, and the swing roller is rotationally supported between the upper end of the first swing arm and the upper end of the second swing arm. The lower end of the first swing arm is in transmission connection with the transmission end of the rotating shaft, the non-transmission end of the rotating shaft is in transmission connection with an adapter plate, the lower end of the second swing arm is arranged on the non-transmission end of the rotating shaft in a sleeving mode, kidney-shaped holes which are evenly distributed in the circumferential direction are formed in the adapter plate, and through holes which are evenly distributed in the circumferential direction are formed in the second swing arm. The adapter plate and the second swing arm are fixedly connected through a fastening bolt penetrating through the kidney-shaped hole and the through hole. The adapter plate is arranged at the non-transmission end of the rotating shaft, the second swing arm is adjusted through the kidney-shaped hole in the adapter plate, angle adjustment of the swing roller is achieved, the purpose of adjusting tension of the left end and the right end of the press roller of the roller press is achieved, the requirement for machining precision of parts is lowered through the connecting structure, and the service life of the adjusting assembly is prolonged.

This application provides an optical module and an electronic device. The housing of the optical module includes a hollow cavity for accommodating a liquid-cooled working fluid, and two first connectors elastically connected to the hollow cavity. A first mounting base is provided at the front of the housing, and each first connector is respectively mounted on the first mounting base. A first constraint and a second constraint exist between the first connector and the first mounting base. When the optical module is inserted or removed, based on the first constraint between the first connector and the first mounting base, the first connector and the main structure of the optical module move synchronously, meeting the reliability requirements of the insertion and removal operation. Based on the second constraint between the first connector and the first mounting base, it can be ensured that no stress is generated during the docking of the first connector and the second connector, maintaining good docking reliability. Furthermore, the second constraint can also adaptively adjust the tolerance accumulation on the dimensional chain of the interface assembly between the optical module side and the device side, providing an adaptive capability to prevent the impact of tolerance accumulation.

The application discloses a kind of based on ultraviolet gluing quasi-monolithic compact interferometer and its building method, it is related to optical element and high-precision laser ranging field, including: the collimator of optical fiber in Mach-Zehnder interferometer and glass mounting seat ultraviolet gluing connection constitute the bottom flat integrated collimator, and integrated collimator and the target position ultraviolet gluing connection of glass base in Mach-Zehnder interferometer;It also includes: for adjusting the position of depolarization beamsplitter and 45 degree mirror in Mach-Zehnder interferometer adjusting support;Adjusting support includes support device for supporting adjusting part, adjusting part includes: six-dimensional optical adjusting frame, it includes: upper layer board;Lower layer board, between upper layer board and lower layer board by multiple screw nails of circumferential surrounding screw connection;Rotary ring is arranged at the bottom of lower layer board;Metal cylindrical connecting rod is fixedly arranged at the bottom of rotary ring.The application can build high stability high-precision quasi-monolithic compact interferometer.

The utility model discloses a presser foot bottom plate, a composite presser foot and a sewing machine in the technical field of sewing machines. A filling groove is arranged on the contact surface of the presser foot bottom plate, and a filling layer made of a material different from that of the presser foot bottom plate is arranged in the filling groove. The bottom surface of the filling layer is located below the contact surface of the presser foot bottom plate, and the distance between the bottom surface of the filling layer and the contact surface is L, where 0 < L ≤ 0.2 mm. The utility model adopts a composite structure, which not only enables the composite presser foot to have the service performance of a plastic presser foot and the service life of a metal presser foot at the same time, but also can reduce the processing precision requirements for the presser foot bottom plate and lower the production cost.

This utility model discloses a spindle unit tail end fixing structure, including a housing, a spindle unit, and a tightening cover. The spindle unit is axially rotatably mounted in the housing with a clearance fit. The tightening cover is fixed to the tail end of the housing by a first screw. The tail end of the spindle unit has an outer conical surface near the inner side of the tightening cover, and the inner side of the tightening cover has an inner conical surface that mates with the outer conical surface. This utility model provides sufficient axial and radial clearance between the tightening cover and the housing, reducing the machining accuracy requirements for the spindle unit and housing mounting holes, thus lowering assembly difficulty and processing costs. Furthermore, the mating of the inner and outer conical surfaces ensures that the tightening cover can be reliably pressed onto the tail end of the housing, improving assembly accuracy and preventing deformation caused by the clearance between the spindle unit and the housing during transmission. This reduces mechanical vibration and wear, extending the service life of the spindle unit.

A scroll compressor includes a motor, a compression mechanism, a drive shaft and a bushing. The compression mechanism includes a fixed scroll and an orbiting scroll. The drive shaft has an eccentric journal. The bushing is designed to be movable relative to the eccentric journal to enable the orbiting scroll to have a variable eccentricity, wherein one axial section of the bushing is arranged between the orbiting scroll and the eccentric journal to enable the drive shaft to transmit power to the orbiting scroll via the one axial section of the bushing, and another axial section of the bushing is designed to limit the range of movement of the bushing relative to the eccentric journal to further define the range of variation of the variable eccentricity of the orbiting scroll. The bushing with the above configuration cooperates with the corresponding structure to reliably and effectively limit the range of movement thereof to enable the orbiting scroll to have a proper variable eccentricity, which reduces the requirement for assembly accuracy of the scroll compressor and thereby reduces the cost of the compressor.

An adjusting pad and a linear guide system for machine tools, belonging to the technical field of machine tool parts, are disclosed. The adjusting pad includes two elongated, sheet-like pads, each fixedly connected at one end by a connecting part. All pads are spaced apart along the length of the connecting part, with a first clearance groove between adjacent pads. The first clearance groove is open at the end furthest from the connecting part. A second clearance groove is provided on the outer side of each pad near the two ends of the connecting part, also open at the end furthest from the connecting part, and open on the side closest to the end of the connecting part. The first and second clearance grooves together provide clearance for all fastening screws. The sides of the second clearance grooves at both ends open simultaneously, eliminating the need for the outermost sheet, reducing the workpiece machining accuracy requirements, and facilitating the insertion and positioning of the adjusting pad, significantly reducing alignment difficulty.

The utility model discloses a split type synchronous transmission mechanism which comprises a gear assembly, a driving shaft, a transmission wheel belt assembly and a driven shaft, the driving shaft is composed of a positioning shaft and a split shaft, the positioning shaft and the split shaft are coaxially arranged, one end of the positioning shaft and one end of the split shaft are detachably connected together, and the other end of the split shaft is detachably connected with the gear assembly. The other end of the positioning shaft can be connected into a motor through a gear assembly, the other end of the split shaft can indirectly drive the encoder to operate through a transmission wheel belt assembly, a driven shaft and a mechano-electronic cam box, and installation and maintenance are very convenient.

The utility model discloses a kind of for capacitor bushing machine's upper sleeve device, including sliding sleeve, upper die needle and upper die needle fixed base, the upper die needle one end is provided with first connector, the first connector is through sliding sleeve sliding connection, the upper die needle other end is provided with second connector, the upper die needle fixed base is provided with mounting hole, the second connector is inserted into mounting hole and is connected with upper die needle fixed base. The utility model upper sleeve device is outside the upper die needle, the recess and projection cooperation of sliding groove and slider in the inside of sliding sleeve, can effectively prevent capacitor bushing from being stuck in the gap between upper die needle and sliding sleeve when being sleeved, reduce the waste of bushing. The utility model also has the advantages of simple structure, high precision requirement of part processing is not required, low production cost, etc., can be adjusted in the process of being installed on capacitor bushing machine, and good applicability.

The utility model discloses a mould isosceles structure in the technical field of forming mould, including lower die seat and lower die core plate. Lower die seat has the core plate groove, and lower die core plate is fixed in the core plate groove. Lower die seat is equipped with a plurality of isosceles columns, and a plurality of isosceles columns are arranged around the outer periphery of the core plate groove. The upper end of isosceles column has the positioning end face. In the mould isosceles structure of the utility model, lower die core plate is positioned through the core plate groove, and the height position of the positioning end face of isosceles column is controlled in accuracy to the effect of mould closing, and the difficulty of detection and processing is low, thereby reducing the machining accuracy requirement and the casting cost of lower die seat, and having important economic significance for production.

The application provides an automatic hole-making end normal sensor calibration method and belongs to the field of aviation manufacturing engineering and airplane assembly technology. The application is based on large-scale high-precision measuring equipment such as a laser tracker, and the high-precision calibration of the relative position and angle of each optical normal sensor emission and the tool axis can be completed on the assembly site by means of a specially-made calibration target plate, the influence of the end effector part machining precision and assembly error is significantly reduced, and the hole-making quality and efficiency of the standard part are ensured.

This utility model discloses a blade ring locking type bearing temperature sensor, aiming to solve the problems of high processing difficulty, poor compatibility when installed on bearings, and complex sensor installation of traditional temperature sensors. The blade ring locking type bearing temperature sensor of this utility model includes a sensor body, a blade ring, and a locking assembly. The blade ring is sleeved on the sensor body and disposed within the locking assembly, which is sleeved on the sensor body. The locking assembly is connected to the temperature measuring hole of the bearing, and the end face of the sensor body abuts against the inner wall of the temperature measuring hole. By pressing the blade ring with the locking assembly, the sensor body can be quickly installed and fixed, simplifying the sensor body installation process and improving the efficiency of installation and maintenance. The position of the sensor body relative to the locking assembly and the temperature measuring hole of the bearing is adjustable, reducing the processing precision requirements of the sensor body and the temperature measuring hole of the bearing, and improving the versatility of the sensor body.

The utility model relates to the technical field of horizontal lift valves, and discloses a valve shaft concentricity adjusting device of a horizontal lift valve. The valve shaft, the outer wall and the valve plate are arranged; the lifting valve adjusting fixing plate and the lifting valve adjusting plate are both mounted at the external position of the valve shaft; the fixed bearing and the ball bearing are both mounted on the lifting valve adjusting plate, and the fixed bearing and the ball bearing are used for fixing the valve shaft; and the adjusting bolt is connected with the lifting valve adjusting and fixing plate. And an air cylinder is fixedly mounted at the end part of the valve shaft. The number of the ball bearings is two, and the two ball bearings are symmetrically distributed on the two sides of the fixed bearing. According to the valve shaft concentricity adjusting device of the horizontal lift valve, the two ball bearings and the fixed bearing are arranged to position the valve shaft fixing column, the heights of the two ends of the valve shaft can be flexibly adjusted, and therefore the requirement of equipment for machining precision is effectively lowered.

The utility model provides a kind of elevator with limiting lifting mechanism, including lower beam assembly, lifting mechanism and limiting piece, lower beam assembly includes two groups of lower beams, two groups of lower beams are all channel-shaped and its opening is set back, lifting mechanism includes linkage lever and governor lifting arm, linkage lever is rotatably installed on two groups of lower beams, governor lifting arm is installed on the part of linkage lever extending two groups of lower beams, positioning pin is arranged between linkage lever and governor lifting arm, limiting piece is installed on lower beam, limiting piece is located above the free end of governor lifting arm.The utility model limits the rotation amplitude of governor lifting arm by limiting piece, avoid governor lifting arm rotation amplitude too large and generate larger impact after being braked, so as to avoid the positioning pin between governor lifting arm and linkage lever be pulled off.Adjustable mounting position of long hole limiting block can reduce the requirement of machining precision and installation precision, and the influence of local wear of limiting block can be compensated.

The utility model discloses a kind of mouth ring mounting structures of pump unit suction port, belong to pump unit field.The mouth ring assembly in the utility model includes mouth ring seat, and the inboard of mouth ring seat is formed with the inlaying space of floating mouth ring;Floating mouth ring is configured as gap fit and is sleeved on the inlet end outside of impeller, and floating mouth ring part is inlayed in the inlaying space of mouth ring seat;The skeleton main body bottom end of outer skeleton is connected with mouth ring seat by extending inward, and the top end of skeleton main body is equipped with everted ring part, and the radial outermost end of everted ring part and pump assembly surface are linear contact interference fit, so that the radial clearance between the outer wall surface of skeleton main body and pump assembly surface is kept.The utility model realizes linear contact fit between pump assembly surface, and the machining precision requirement of pump body assembly groove can be obviously reduced, can be obtained by simpler processing mode, and assembly technology tolerance improves, more conducive to production and processing, reduce production maintenance cost.

This invention relates to the field of door and window technology, and discloses an aluminum-clad wood door and window corner process, including an aluminum corner structure, a wood frame assembly, and a snap-fit ​​connection mechanism. The process includes the following steps: aligning the boss at the end of the wood frame with the guide groove of the aluminum corner, and inserting the boss into the guide groove at a 45° angle; rotating the wood frame to a vertical position until it is engaged and locked by the snap-fit ​​connection mechanism, and confirming that the wood frame is not loose after locking; applying weather-resistant sealant between the wood frame strip and the wood frame, and using self-tapping screws with anti-loosening structure to fix the wood frame strip and the wood frame together, completing the assembly. By using a standard aluminum corner and snap-fit ​​connection, the automatic engagement characteristic of the snap-fit ​​connection simplifies the on-site assembly process. The improved structure reduces the processing precision requirements of the wood components, reduces the scrap rate caused by dimensional deviations, and improves the utilization rate of raw materials, solving the shortcomings of low on-site assembly efficiency, high dependence on personnel skills, and serious waste of raw materials.

The utility model discloses a kind of zero-leakage gas one-way valve sealing structure, including valve body and valve core subassembly, valve core subassembly is arranged inside valve body, and including valve core, rubber sealing block and screw;Valve core's step portion is fixed with rubber sealing block, the sealing block has plastic deformation ability, can keep constant sealing specific pressure under different working pressure, realize reliable sealing under high-low pressure environment;Valve body inside is equipped with conical section, and rubber sealing block is attached to form seal, conical section is low in machining precision requirement, facilitate assembly;Valve core subassembly opens passage when inflating, allow gas to flow into pressure storage container;After stopping inflation, spring and gas pressure jointly act, so that sealing block is tightly attached to conical section, cut off gas circuit, prevent gas leakage;In addition, inlet end is equipped with filter screen, prevent impurities from entering, improve the reliability and service life of valve;The utility model structure is simple, sealing is reliable, applicable to high-pressure gas storage and industrial pneumatic system etc. scene.

The invention provides a large-tolerance self-adaptive assembly joint for space assembly and a spacecraft. The method can be used in the technical field of spacecraft on-orbit assembly. The large-tolerance self-adaptive assembly joint for space assembly is provided with a mounting hole, and the mounting hole is at least used for being arranged on the outer side of a first connecting part and the outer side of a second connecting part in a sleeving mode. The large-tolerance self-adaptive assembly joint for space assembly is made of memory alloy, and the hole expansion rate of the large-tolerance self-adaptive assembly joint for space assembly is larger than or equal to 20%. The aperture of the mounting hole is adjustable, and when the aperture of the mounting hole is increased, the length of the large-tolerance self-adaptive assembly joint for space assembly is increased or decreased. According to the large-tolerance self-adaptive assembly joint for space assembly, the requirements for self-adaption and large assembly tolerance of the joint can be met by improving the structural design and the hole expansion rate of the joint.