118 results about "Strong coupling" patented technology

The invention relates to the technical field of welding quality detection, in particular to a surfacing process quality monitoring method, system and equipment, and the method comprises the steps that a dynamic parameter set of the surfacing process is obtained in real time, and the dynamic parameter set comprises arc characteristic parameters, temperature field distribution parameters and mechanical state parameters; setting an edge computing node, accessing the welding quality prediction model, inputting a dynamic parameter set, and outputting a quality evaluation result containing a defect probability and a fusion depth prediction value; a welding parameter adjusting instruction is generated based on the quality evaluation result, and the operation states of a welding power source and a wire feeding mechanism are adjusted in real time; and updating the dynamic parameter set according to the welding parameter adjusting instruction and transmitting the dynamic parameter set to the industrial control switchboard based on the edge computing node. According to the invention, the problem of uncontrollable instantaneous quality fluctuation caused by strong coupling of multiple physical fields in the surfacing process is effectively solved.

The invention discloses a two-arm robot motion planning method, system and device for a strong coupling scene, and the main content is as follows: constructing a strong coupling two-arm robot closed chain system kinematic model, giving a group of mechanical arm # imgabs0 # joint configuration, and outputting a joint configuration set corresponding to another mechanical arm # imgabs1 # through the kinematic model, therefore, the planning space dimension is greatly reduced; according to a master-slave batch self-adaptive planning strategy, a mechanical arm # imgabs2 # carries out active batch self-adaptive path planning, and then a mechanical arm # imgabs3 # carries out passive batch self-adaptive path planning based on the strong-coupling double-arm closed-chain system kinematic model; and carrying out pre-motion safety check on the double-arm robot to ensure absolute safety of double-arm cooperative motion in the closed chain operation process. The problems of real-time performance and safety in a strong coupling scene are effectively solved, and reliable technical support is provided for industrial-grade double-arm cooperation.

The invention relates to the technical field of computer science and industrial engineering, in particular to a tool workshop scheduling method, which comprises the following steps of: acquiring production characteristics of a current tool workshop, generating an optimal batch scheduling strategy according to the production characteristics of the current tool workshop based on a preset evolutionary strategy, and automatically designing an algorithm by utilizing a preset large model, and calculating the minimum completion time and the maximum completion time of the optimal batch scheduling strategy, and completing tool workshop scheduling according to the minimum completion time and the maximum completion time based on the optimal batch scheduling strategy. Therefore, the problems of high workshop scheduling complexity and the like caused by strong coupling of batch division and working procedure sorting, strict constraint between working procedures and high resource networking degree in workshop scheduling are solved, an automatic algorithm design framework based on a large model is introduced, the expert algorithm design time is shortened, and the workshop scheduling efficiency is improved. Therefore, the efficiency and feasibility of aircraft tooling production scheduling are improved.

The invention discloses an ultra-high-temperature heavy-load self-aligning roller bearing optimization design method and system based on a particle swarm algorithm, belongs to the field of rolling bearing optimization design, and solves the problems that a traditional bearing design process is low in efficiency, and multi-target collaborative optimization is difficult to achieve. And the design method combining the empirical formula and the finite element model is poor in precision due to the strong coupling characteristic of the material nonlinearity, the thermal coupling effect and the bearing performance under the ultra-high-temperature heavy-load working condition. The method comprises the following steps: S1, determining a bearing parameter, a working condition parameter and a particle swarm algorithm parameter; s2, establishing an optimization model of the ultrahigh-temperature heavy-load self-aligning roller bearing: S21, establishing a target function; s22, determining a design variable; s23, establishing a constraint equation; and S3, optimizing corresponding parameters of the bearing by adopting a particle swarm algorithm to obtain an optimization result. The method is suitable for a self-aligning roller bearing optimization design scene.

The invention discloses a strong-coupling phased-array antenna unit loaded with a metasurface structure, belongs to the technical field of antenna engineering, and relates to a strong-coupling phased-array antenna. According to the metasurface structure for improving the wide-angle scanning performance of the strong-coupling phased-array antenna, on the basis of square metal patches which are periodically and uniformly distributed, rectangular patches which are specially distributed and are inconsistent in length and width are introduced, so that a non-uniform metasurface matching layer structure is formed. When the H-plane wide-angle scanning of the strong-coupling phased-array antenna is carried out, the rectangular patch can equivalently play a role of a director, and the impedance change is smoother, so that the H-plane wide-angle scanning performance of the strong-coupling phased-array antenna is remarkably improved. Meanwhile, the metasurface structure has small influence on the wide-angle scanning performance of the E plane, so that the antenna can achieve good wide-angle scanning performance in both the E plane and the H plane. The metasurface is simple in structure and has the advantages of being single-layer, light in weight and easy to process.

The invention discloses a strong coupling process prediction method based on large model fine tuning, and relates to the technical field of industrial process intelligent optimization, and the method comprises the steps: S1, carrying out the cleaning, coupling feature extraction, time sequence standardization and VAE small sample enhancement of strong coupling process original data, and obtaining standardized time sequence data; s2, selecting a Transform architecture industrial time sequence pre-training large model as a base model; s3, through a layered freezing-fine tuning mechanism, freezing a bottom-layer general knowledge layer, performing fine tuning on a middle-layer coupling feature adaptation layer and a top-layer multi-branch output layer, and completing model adaptation in combination with a weighted loss function containing a coupling constraint regular term; and S4, inputting data to obtain a prediction result, and realizing rapid iteration of the model through increment fine tuning. The method is suitable for strong coupling scenes of chemical engineering, metallurgy and the like, an iron-making and steel-making process is taken as an experimental case, the predicted MAE of the molten iron temperature reaches 9.2 DEG C, the predicted MAE of the carbon content of the molten steel reaches 0.012%, the generalization accuracy rate is 93%, the prediction precision and the industrial suitability are remarkably improved, and the production energy consumption and cost are reduced.

The invention discloses an electromagnetic actuator with a rigidity compensation function. The end face of the inner side of a stator iron core of a C-shaped structure is provided with a trapezoidal slope notch, and the working face of a rotor is a slope matched with the notch of the stator iron core; the N pole and the S pole of the permanent magnet are attracted to the upper end arm of the stator core, the coil winding is wound on the yoke portion of the stator core, the flexible guide mechanism is connected with the rotor and the base, the lower end arm of the stator core is connected with the base through a fastener, and the fastener is screwed to adjust the relative distance between the end face of the stator core and the working face of the rotor. According to the invention, the rotor and the stator core form an inclined air gap, and the linear displacement of the rotor is not equal to the normal thickness of the air gap any more, but is amplified in geometrical relationship. The fundamental contradiction of strong coupling of the stroke and the thickness in a traditional plane air gap is overcome, on the premise that a small initial normal air gap is maintained, the macroscopic motion stroke several times of the thickness is achieved, and the problem that large stroke and high linearity are difficult to consider at the same time is solved from the structural principle.

The invention relates to a force control method and system for a double-leg supporting hydraulic power-assisted exoskeleton and the exoskeleton. The force control method for the double-leg supporting hydraulic power-assisted exoskeleton comprises the following steps that 1, the sampling period of a real-time controller is initialized; step 2, acquiring state data of the exoskeleton; 3, the motion states of the left leg foot and the right leg foot are judged respectively, and state data are corrected in real time according to the motion states; and 4, establishing a physical model of the double-leg supporting hydraulic power-assisted exoskeleton. According to the invention, a multi-input multi-output adaptive robust control algorithm is utilized, a cascade force control method is adopted, and an upper layer controller and a lower layer controller are designed. A moment distribution algorithm is designed in a lower-layer controller, so that the influence of closed chain dynamics of the double-leg supporting hydraulic exoskeleton under the condition of a double-leg supporting state is effectively overcome. Under the condition that the control input number is smaller than the exoskeleton motion freedom degree number, the influence of multi-joint strong coupling and model uncertainty of the exoskeleton is effectively overcome.

The present invention relates to a quantum computer comprising NV centers in diamond as quantum bits, nuclear spins of nuclei strongly coupled to the NV centers, strongly constrained by these NV centers, as nuclear quantum bits (hereinafter referred to as strong nuclear quantum bits), and nuclear spins, weakly constrained by these NV centers, of nuclei weakly coupled to the NV centers as nuclear qubits (hereinafter referred to as weak nuclear qubits). The resonance energy for coupling the weakly coupled nuclear spins of the nuclei weakly coupled to the respective NV centers depends only weakly on the respective spin state of the electron configuration of the NV centers weakly coupled to that nuclear spin. The control mode of the quantum computer on nuclear spin under weak constraint of the NV center is different from the control mode of the quantum computer on nuclear spin under strong constraint of the NV center. To this end, the quantum computer preferably has a kernel qubit database that stores information about whether the kernel qubits are strongly coupled or weakly coupled.

The invention belongs to the technical field of digital design of Roots blower equipment, and particularly relates to a digital twinning-based dynamic performance digital design method of a blower, which comprises the following steps of: constructing a multi-component parameterized structure model of the blower, establishing a multi-physics field coupling model of pneumatic, structural, thermal, electromagnetic and sound fields, and constructing a digital twinning model of the blower. Dynamic boundary conditions such as flow disturbance, inertia force and base disturbance are loaded, a digital twin model synchronous with a physical fan state is constructed, master-slave type strong coupling joint solution is executed, multi-field response indexes are extracted and normalized analysis is carried out, and finally optimization design parameters of the fan are output through a multi-target optimization feedback mechanism. According to the method, multi-domain balance design among fan structure performance, electromagnetic response, thermal stability and acoustic characteristics can be achieved, modeling precision and parameter optimization capacity are improved, and the method is suitable for digital development of high-reliability roots blower equipment under complex operation conditions.

The invention relates to the technical field of laser cutting, in particular to an intelligent steel structural part blanking method based on laser cutting, which comprises the following steps: acquiring three-dimensional shape data, reflectivity data, alloy element concentration and alloy element concentration distribution of the surface of a movable arm mainboard in a cutting pre-scanning area; the reflectivity is decomposed through the alloy element concentration, and the inherent reflectivity and the deformation-induced reflectivity are obtained; and synchronizing the acquired data according to a timestamp, and generating a basic state vector of the detection point. According to the method, a multi-dimensional risk assessment system is constructed by defining a strong coupling region (first-level risk), a high warping region / element segregation region (second-level risk) and a high reflection region (third-level risk) and combining parameters such as a coupling boundary response function and an element concentration gradient; a hierarchical control strategy and feedforward prediction are designed for different region types; the key process problem in high-strength steel laser cutting is solved in a unified mode, and the precision, efficiency and stability of steel structural part blanking are remarkably improved.

The present disclosure relates to a superconducting quantum chip connection structure used for connecting between superconducting quantum chips. The superconducting quantum chips comprise quantum substrates and quantum circuits. The connection structure includes: a connection portion for connecting the superconducting quantum chips; and a current conversion portion disposed on the quantum substrate for bonding and connecting the quantum circuits to the connection portion, so that the standing wave current of the standing wave mode used for communication at the bonding connection interface is close to zero. The present disclosure can not only significantly reduce channel loss and achieve stronger coupling, but also significantly reduce energy loss at the bonding connection interface, thereby reducing the impact on quantum state transmission efficiency.

The invention discloses an access device based on extended backboards and a routing method based on the extended backboards, and relates to the technical field of storage equipment, each to-be-accessed backboard is disorderly accessed to a one-to-multiple cable of each port group, an integrated circuit bus controller reads a backboard identifier of the to-be-accessed backboard accessed to each electrical equivalent physical port; according to the backboard identifier, the logic slot position of each to-be-accessed backboard is determined, and no matter which branch cable of the one-to-many cable accesses each port group, each to-be-accessed backboard is mapped to the corresponding logic slot position. And aggregating the backboard signals in each port group to obtain a backboard signal set of each port group, and routing each backboard signal in the backboard signal set of each port group to the corresponding logic slot according to the corresponding relationship between the backboard identifier of each to-be-accessed backboard and the logic slot. Strong coupling of a physical connection sequence and a logic slot position is broken, and the flexibility of accessing a plurality of backboards on the expansion backboards is improved.

The present invention provides a strong-coupling charging magnetic coupling mechanism and its load identification method, comprising a transmitting coil, a receiving coil, and a ferrite. The coupling coefficient between the transmitting coil and the receiving coil is constant. The transmitting side is provided with a capacitor and an inductor, the inductor being obtained by short-circuiting the primary. The receiving side has a load. By resonating the capacitor and inductor to achieve a constant voltage output independent of the load, the load resistance can be calculated. Accurate load identification can better meet the requirements of the control strategy.

The invention discloses a vibration measurement and control device of a frame type multilayer vibration isolation platform. The vibration measurement and control device comprises a device body part, a vibration isolation damping part, a quasi-zero stiffness coupling part, an upper functional assembly part, a flexible beam part, a vibration detection part and a control part. The multi-layer strong coupling link of vibration excitation, magnetic damping vibration isolation, the quasi-zero stiffness system, the rotating platform and elastic connection is realized on the same platform, so that the coupling transmission and modal interaction can be conveniently researched.

The utility model relates to the technical field of low-frequency sound insulation, in particular to a low-frequency sound insulation mortar structure which comprises bearing columns, first steel bar sets are fixedly installed in the bearing columns, a wall body mechanism is arranged between the bearing columns, a base mechanism is arranged at the bottom ends of the bearing columns, and the wall body mechanism comprises a brick body wall. The brick body wall is fixedly installed between the bearing columns, sound insulation mechanisms are arranged at the front end of the brick body wall, the heavy balls coated with the soft layers are placed in the base body formed by combining the whole sound insulation mechanisms to form the resonance unit with low frequency, and when the frequency of elastic waves propagated in the base body is close to the resonance frequency of the resonance unit, the sound insulation mechanism is arranged on the brick body wall. The resonance structure units and elastic waves generate a strong coupling effect, so that the elastic waves cannot be continuously propagated forwards, thereby causing the generation of band gaps, realizing the control of large wavelength by small size, and generating a sound insulation effect.

The present invention provides a filter and its coupling structure, which is installed in a cavity. A cover plate is covered on the cavity, and at least two resonant rods are also provided in the cavity. The coupling structure includes a coupling plate, and the coupling plate is fixed on the side of the cover plate close to the cavity and is located between two adjacent resonant rods. In the coupling structure of the present invention, the coupling plate is directly attached and fixed to the inner side of the cover plate. The energy at the top of the resonant rod is the largest. Therefore, setting the coupling plate on the inner side surface of the cover plate is to achieve cross-coupling at the top of the resonant rod. Only a very small coupling area is required to meet a strong coupling amount. Compared with the flying rod structure that uses the side surface of the resonant rod to achieve coupling in the prior art, it does not need to make the coupling disk very large to achieve the same coupling amount. Moreover, the fixed structure is stable by using the attachment and fixing method, the structure is simpler, the requirement for processing accuracy is not high, and the production and processing efficiency is greatly improved and the production cost is reduced.

The invention discloses a BOPP (Biaxially-oriented Polypropylene) rolling driving safety linkage control method, which relates to the technical field of industrial automation control and comprises the following steps: establishing an electromagnetic disturbance distribution diagram of a driving and rolling signal transmission path, extracting electromagnetic coupling strength distribution on the basis of a current pulse space diffusion track generated by a driving device and a rolling device in a start-stop stage, and calculating a driving speed of the driving and rolling signal transmission path; and dividing a strong coupling region and a weak coupling region according to the coupling strength to form a continuous electromagnetic characteristic band. The delay absorption layer and the reverse phase shift guide chain are arranged in a signal path, so that layered energy absorption and reverse phase counteracting are realized, electromagnetic pulse propagation is weakened, and false triggering is prevented; and meanwhile, a low-amplitude periodic slip signal is injected into the signal input end, so that the channel frequency generates micro-amplitude wandering, a dynamic self-adaptive anti-interference mechanism is formed, and stable and reliable signal transmission is ensured.

The present invention provides a miniaturized sheet metal combiner, in which the front and rear ends of each resonant plate are bent upward to form a bent structure for coupling adjacent resonant plates. The coupling is enhanced by adjusting the distance and relative area between the bent structures of adjacent resonant plates, thereby achieving adjustment of the coupling bandwidth. Under volume constraints, the height and volume of the bent structure are significantly reduced compared to the general coaxial metal solution. At the same time, a tuning channel is provided on the cover plate above the bent structure of any two adjacent resonant plates, and the distance and relative area of the bent structure are changed by prying the tuning channel on the cover plate, thereby effectively enhancing the coupling, reducing the number of debugging parts, and saving costs. Moreover, the present invention adjusts the performance of the combiner through the sheet metal resonant plates and the flying rod plates and connecting rods that generate capacitive and inductive cross coupling. While achieving the same frequency index, the overall weight is significantly reduced.

The application discloses an industrial full-link through implementation method based on unique identification and double contract anchoring, and belongs to the technical field of intelligent manufacturing informatization. The method takes a plan number as a unique and unchangeable identification throughout the full life cycle from raw material warehousing to finished product warehousing, takes a contract hash value as a cross-table association anchor point, adopts a step-by-step anchoring mechanism of sales contract priority binding and procurement contract subsequent binding, and combines batch processing, transaction safety control and full-chain backtracking synchronization technology to realize bidirectional synchronous updating of procurement and sales contract information in full life cycle data tables such as raw material inventory tables and production process quality inspection record tables. The application breaks the strong coupling of the procurement and production processes, supports cost information post-recording, solves the pain points of data disconnection, untraceability, low efficiency and maintenance difficulty of traditional industrial software, has a simple architecture, high performance and stable operation, and is suitable for various intelligent manufacturing systems such as MES and ERP. The application has been applied in actual industrial scenes and has industrialization popularization capability.

The present invention discloses an electromagnetic wave absorbing unit and an electromagnetic wave absorbing structure. The electromagnetic wave absorbing unit includes a first dielectric layer and a first metal unit structure and a second metal unit structure respectively arranged on the upper and lower end surfaces of the first dielectric layer. The first metal unit structure includes an upper metal arm, a lower metal arm, a left coupling line, and a right coupling line, which are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. The second metal unit structure includes a left metal arm, a right metal arm, an upper coupling line, and a lower coupling line, which are arranged in an array along the horizontal and vertical directions on the end surface of the first dielectric layer. Through the coordination between the metal arms and the coupling lines, strong coupling is formed between adjacent metal arms, and the impedance and resistance between the metal arms are well matched, thereby broadening the absorption bandwidth of the electromagnetic wave absorbing unit and the electromagnetic wave absorbing structure.

Wideband antenna elements exhibit strong coupling when formed into an array, which normally degrades the impedance bandwidth, radiation pattern, and efficiency of the feed antennas. Various methods are provided herein to mitigate or reduce this coupling. For example, designing an array such that not all antennas support the lower frequency operation mitigates coupling at low frequencies where coupling is most significant. Alternatively, embedding the feeds into a high-refractive-index medium increases the electrical distance between feeds while the physical separation is kept constant.

The present invention provides an MEMS gyroscope and an electronic product. The MEMS gyroscope comprises a plurality of first mass blocks, a second mass block and coupling parts, wherein the plurality of first mass blocks are located at two opposite sides of the second mass block in a first direction; and each coupling part comprises a coupling link and a plurality of connecting beams connected to two ends of the coupling link, the connecting beams are flexible beams, and the coupling part is positioned between the first mass blocks and the second mass block and connects the first mass blocks with the second mass block. Through the arrangement of the coupling links, strong coupling can be realized between the first mass blocks and the second mass block, so that the anti-interference performance of the MEMS gyroscope is enhanced during work and the working stability is improved.

The application provides a broadband symmetrical amplitude equalization directional coupler and a coupling method, relates to the technical field of microwave radio frequency passive devices, and comprises the following parts: a single-section coupling line located in an input through branch, the single-section coupling line being a double-layer metal biased wide-side coupling line; a symmetrical amplitude equalizer connected to a coupling port and an isolation port respectively; and an LC matching network connected to an input port and an output port respectively, so that the directional coupler suitable for 18-50GHz can be constructed, and strong coupling of the directional coupler is realized.

The invention discloses a power control method of a strong coupling emission array system, which is used for coping with instability and uncertainty phenomena in a system power increasing process. According to the method, the power adjustment process is divided into a plurality of stages, the target power of the first stage is the safe power of the transmitter capable of working under the total reflection condition, and after the target of the first stage is completed, array element phase adjustment is carried out according to beam pointing. In the power adjustment process of each stage, the amplitude of the uncertainty of the system state is reduced by controlling the gain change step pitch, the iteration step number and the error tolerance, the system is prevented from entering the oscillation state, and the uncertainty of the final state of the system is effectively eliminated. The method is low in complexity, easy in engineering implementation, stable in power control process, high in speed and particularly suitable for a large-scale strong coupling emission array system.

The utility model discloses a high-pass and low-pass duplexer with a pure copper sheet structure, and belongs to the field of filters. A high-pass and low-pass duplexer with a pure copper sheet structure comprises a shell and a cavity arranged on the shell and further comprises a common end input connector, a low end output connector and a high end output connector which are all arranged on the outer wall of the shell. The common end input connector, the low end output connector and the high end output connector are connected with an input core rod, a low end output core rod and a high end output core rod respectively. The high-low pass copper sheet is arranged in the cavity, and the input core rod, the low-end output core rod and the high-end output core rod are arranged at one end in the cavity and correspond to the high-low pass copper sheet; according to the utility model, the disadvantage that strong coupling is difficult to realize in the design of a broadband combiner is solved, a relatively wide passband can be realized, and the design is relatively easy to control product indexes, free of tuning, small in size and high in consistency; and the processing consistency and the cost are relatively low, and the control is easy.

The utility model provides a six-degree-of-freedom hexagonal bearingless permanent magnet synchronous motor with precise compensation and decoupling, the problem of precise compensation and strong decoupling can be solved, a permanent magnet adopts an integrated installation mode and is fixed on a stator and a rotor, and a six-pole 12-slot winding installation structure is adopted. Freedom-degree suspension force in six directions can be generated when the rotor rotates by 60 degrees every time, stable suspension of the motor rotor can be guaranteed by shifting the rotor by 60 degrees, and a six-freedom-degree magnetic field air gap is generated. A coil is wound in each stator groove, when current passes through the coils, corresponding degree-of-freedom control can be achieved, six permanent magnet rings and six triangular permanent magnets are installed on the surface of the rotor in an adsorption mode, an integrated installation mode is adopted, high-frequency output of torque can be achieved, and six-degree-of-freedom stable suspension can be achieved. The device is simple and convenient in structure, and can achieve the effects of compensation of rotor position offset, fast dynamic response and accurate compensation of strong coupling.

The present invention provides a CFD-6DOF strong coupling numerical calculation method for the transient self-flow process of a vane pump, including: S1: establishing a hydrodynamic geometric model file; S2: performing discretization processing and mesh division; S3: coupling the hydrodynamic control equation and the six-degree-of-freedom motion equation; S4: setting the initial boundary conditions and the inherent physical properties of the rotor rigid body structure; S5: calculating the torque generated by each grid node on the rotor structure wall surface; S6: calculating the angular velocity generated by the rotor at the time step of S5 to obtain the angular displacement; S7: updating the positions of each grid node in the rotating domain and correcting the flux field; S8: solving the flow field at the next time step of the system, iteratively correcting the flow field, and returning to S5 to perform cyclic calculations for each time step until the calculations for all time steps are completed and the results are output; S9: differentiating the angular displacements calculated for each time step. The present invention can obtain the transient evolution law of the flow field during the self-flow process of the pump, making the numerical analysis results closer to the actual engineering requirements.

This invention belongs to the field of semiconductor device manufacturing process control technology, specifically relating to a method for optimizing process parameters in VCSEL epitaxial wafer production. The method includes: constructing a multi-loop PID control system based on process parameters and key quality indicators during VCSEL epitaxial wafer growth; online identification of the ARX model during PID control system operation; calculation of the steady-state process gain matrix characterizing the steady-state causal relationship of the system; identification of the coupling direction based on the sign of the steady-state gain; and calculation of the antagonistic coupling strength factor and the cooperative coupling strength factor. The PID controller gain is then dynamically adjusted to achieve control of the epitaxial wafer growth process. This invention improves the response speed and robustness of each control loop while ensuring the overall stability of the multivariable control system, effectively reducing layer thickness and composition fluctuations caused by parameter drift and strong coupling during VCSEL epitaxial wafer growth, and improving the growth accuracy of the epitaxial wafer.

The resin mesh section allows the product to be kept in the resin case for an extended period. [Solution] The mesh portion is cylindrical with one end open and the sides closed. The case comprises an opening-holding portion that holds the entire outer circumference of one end of the mesh portion, and a frame portion that holds a part of the outer circumference of the side of the mesh portion. Multiple ribs are formed on the opening-holding portion of the case, spaced apart in the circumferential direction. The entire circumference of the opening-holding portion faces the entire circumference of one end of the mesh portion, and only a part of the circumferential direction of one end is embedded within the ribs, forming a strong coupling portion that is strongly connected to each other. In the parts other than the strong coupling portion, a weak coupling portion is formed where the mesh portion is not embedded. One end of the mesh portion and the opening-holding portion of the case are mainly connected by a pre-set strong coupling portion. Stress will concentrate between the mesh portion and the case at this strong coupling portion, but since the area where stress concentrates can be identified during the design phase, the coupling portion can be set in an area and position that will not peel off even if stress concentrates.