Ceramic spark plug polymer buffer rubber sleeve rotary assembly tool and intelligent loss prevention method

Abstract

The invention discloses a ceramic spark plug polymer buffer rubber sleeve rotary assembly tool and an intelligent damage prevention method. The tool comprises a rotary drive module, a buffer guide module, a torque control module, an over-twisting prevention module and a state monitoring module. A spark plug ceramic body is coated with a polymer rubber sleeve formed by compounding an elastic buffer layer and a rigid guide layer, and stress dispersion and accurate guide are realized in combination with flexible torque transmission of a magneto-rheological coupling. The dynamic torque controller intelligently adjusts the output torque based on ceramic strain data monitored in real time and triggers reverse rotation protection when the output torque exceeds a threshold value. The over-screwing prevention module blocks the over-screwing risk through mechanical limiting and electrical interlocking. A five-stage screwing-in control strategy is adopted, laser positioning, self-adaptive rotating speed adjusting and pulse screwing-in technologies are fused, and the problems of ceramic damage, thread damage and assembly eccentricity are synchronously solved.

Description

TECHNICAL FIELD

[0001] The present application relates to the technical field of internal combustion engine assembly, and particularly relates to a ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool and an intelligent damage prevention method. BACKGROUND

[0002] In the field of internal combustion engine assembly, the installation of a ceramic spark plug on a cylinder head has long been plagued by systematic technical bottlenecks. Traditional assembly tools use rigid metal clamps to clamp the hexagonal part of the spark plug, and the structural defects of the metal clamps lead to the following key problems:

[0003] Stress concentration damage: the metal clamp directly contacts the ceramic body, lacks a stress buffering mechanism, and the rotary torque is concentrated in the local area of the ceramic body, causing micro-cracks;

[0004] Lack of guidance accuracy: the alignment of the threaded hole relies on manual visual positioning, and there is no active correction mechanism, which leads to the eccentricity of the spark plug axis and the cylinder head screw hole;

[0005] Risk of over-tightening out of control: the assembly depth is controlled by experience, and there is no mechanical-electrical linkage protection mechanism, which easily causes thread slipping or cylinder head damage;

[0006] Insufficient production line flexibility: a single tool structure cannot be compatible with multiple specifications of spark plugs, and production line changeover requires downtime to replace equipment, reducing production efficiency.

[0007] Based on the above defects, the present application provides a ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool and an intelligent damage prevention method to solve the above technical problems. SUMMARY

[0008] This section is intended to summarize some aspects of the embodiments of the present application and briefly introduce some preferred embodiments. Some simplifications or omissions may be made in this section and the abstract and title of the specification to avoid obscuring the purpose of this section, the abstract and the title, and such simplifications or omissions cannot be used to limit the scope of the present application.

[0009] Therefore, to solve the above technical problems, the present application provides the following technical scheme: a ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, comprising:

[0010] A rotary drive module includes a servo motor and a rotary sleeve driven by the servo motor;

[0011] A buffer guide module includes a rubber sleeve coaxially connected to the rotary sleeve, the rubber sleeve is composed of an inner elastic buffer layer and an outer rigid guide layer, and the inner elastic buffer layer covers the ceramic body of the spark plug;

[0012] The torque control module comprises a magneto-rheological coupling arranged between the rotating sleeve and the rubber sleeve, and the magneto-rheological coupling is connected with a dynamic torque controller; the dynamic torque controller executes a dynamic torque compensation algorithm, and real-time correction of output torque is performed according to spark plug ceramic body micro-strain data detected by a fiber grating sensor;

[0013] The anti-over-tightening module comprises a ring-shaped limiting protrusion arranged at the end of the rubber sleeve, and a guide joint is arranged at the bottom of the ring-shaped limiting protrusion.

[0014] The state monitoring module comprises a piezoelectric film sensor embedded in the inner elastic buffer layer and a fiber grating sensor arranged on the inner wall of the rubber sleeve.

[0015] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the inner elastic buffer layer is made of a microporous structure high-damping elastic material, and the outer rigid guide layer is made of glass fiber reinforced engineering plastic.

[0016] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the outer diameter of the ring-shaped limiting protrusion of the anti-over-tightening module is greater than the size of the hexagonal part of the spark plug, when the ring-shaped limiting protrusion contacts the cylinder cover plane, tactile feedback is generated and the servo motor is triggered to be powered off, and the taper angle of the bottom guide joint matches the thread guide angle of the spark plug.

[0017] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the tool further comprises a modular adaptation mechanism, which comprises a quick-change interface arranged at the top end of the rubber sleeve and a detachable adaptation ring, and the inner diameter of the adaptation ring matches different spark plug specifications.

[0018] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the tool further comprises a bearing tube module, and the bearing tube module comprises a bearing tube, the servo motor is arranged in the bearing tube, and one end of the bearing tube is provided with a connector mounting position for connecting a device to monitor torque.

[0019] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the inside of the bearing tube is provided with a multi-cylinder branch channel, the bearing tube is provided with a wire joint for wire access, the bearing tube is provided with a mounting bracket for fixing and position adjustment of the tool device.

[0020] As a preferred scheme of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the piezoelectric film sensor of the state monitoring module is arranged in an array, and real-time collection of spark plug ceramic body surface stress distribution data is realized; the fiber grating sensor is arranged along the axial direction of the rubber sleeve, and the micro-strain of the spark plug ceramic body is monitored.

[0021] The intelligent damage prevention method of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool is applied to the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool in any one of the preceding aspects, and comprises the following stages:

[0022] Pre-alignment stage: spark plug and cylinder head threaded hole ±0.05mm positioning is performed through device assistance;

[0023] Initial screwing-in stage: the servo motor is operated at a speed of ≤50rpm, the torque limit is ≤5N·m, and the torque rising slope is ≤2N·m / s;

[0024] Thread engagement stage: a dynamic torque compensation algorithm is started, and the speed is increased to 100-150rpm;

[0025] Critical torque stage: when the torque reaches 15-18N·m, the pulse mode of 200ms forward rotation and 100ms pause alternation is switched to;

[0026] Final locking stage: after the annular limiting protrusion contacts the cylinder head plane, the servo motor power is cut off.

[0027] As a preferred scheme of the intelligent damage prevention method of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool, the dynamic torque compensation algorithm comprises the following steps:

[0028] Signals from the fiber Bragg grating sensor are collected and denoising processing is performed;

[0029] Real-time strain ε1 is output in real time through the fiber Bragg grating sensor, and the target strain threshold ε2 is calculated by the following formula:

[0030] ε2=σ2 / E;

[0031] Wherein, σ2=8MPa, and E is the elastic modulus of the ceramic body;

[0032] According to the real-time measured ε1 and the target strain difference threshold ε2 of each sampling period, the torque correction amount is calculated by the following formula:

[0033] ΔT=K c ×(ε2-ε1);

[0034] Wherein, the compensation gain K c ∈[0.1, 0.5], unit: N·m / με;

[0035] When ε1>ε2, the servo motor is driven to rotate in reverse at 50% of the current speed for 0.1s, and the local stress is quickly released;

[0036] When the reverse rotation is triggered, the dynamic torque controller forcibly interrupts other control instructions, executes the 0.1s reverse rotation action preferentially, and automatically resets to the current stage basic speed 100-150rpm after the end.

[0037] As a preferred scheme of the intelligent anti-damage method of the polymer buffer sleeve rotary assembly tooling of the ceramic spark plug, in the threaded engagement stage, when the piezoelectric film sensor array of the state monitoring module detects that the surface stress distribution unevenness U of the ceramic body of the spark plug is greater than 20%, the screw-in rotating speed of the servo motor in this stage is reduced by 30%, and after 2s, it is restored to the current stage basic rotating speed 100-150rpm.

[0038] Wherein, the surface stress distribution unevenness U of the ceramic body of the spark plug is calculated according to the following formula:

[0039]

[0040] Wherein, σ i The surface stress value of the ceramic body of the spark plug detected by the i-th piezoelectric film sensor, with the unit of MPa;

[0041] The average value of the surface stress of the ceramic body of the spark plug detected by each piezoelectric film sensor.

[0042] The beneficial effects of the present application are:

[0043] 1. The present application is provided with a polymer sleeve composed of an inner elastic buffer layer and an outer rigid guide layer, the layered buffer structure disperses the surface stress of the ceramic body of the spark plug through the elastic deformation of the inner layer, and the outer layer ensures the accuracy of the screwing-in trajectory, solving the technical problem of stress concentration damage caused by hard contact; the flexible torque transmission chain is formed by the combination of the magneto-rheological coupling and the dynamic torque controller, the impact torque peak value is suppressed, the reverse rotation protection triggered by the strain threshold is combined, and the impact torque peak value is actively suppressed; the servo motor is triggered to be powered off when the annular limiting protrusion contacts the cylinder head plane, and the over-tightening risk is physically blocked; through the above structure design, the breakage rate of the ceramic body of the spark plug is significantly reduced, and the assembly jam caused by the thread engagement deviation is eliminated.

[0044] 2. The present application realizes the rapid switching of different specifications of spark plugs through the combination of the quick-change interface and the detachable adapter ring, so that the tooling is compatible with multiple types of spark plug assembly and adapts to the assembly requirements of multiple specifications of spark plugs; the torque control algorithm automatically adapts to the structural differences of the spark plug, without manual parameter resetting; through the above structure design, the tooling supports mixed production of multiple types of spark plugs, and significantly reduces the changeover downtime.

[0045] 3、The piezoelectric film sensor array detects the stress distribution on the surface of the spark plug ceramic body, the fiber grating sensor captures the micro-strain in real time, and the dual-redundancy quality feedback during the assembly process is constructed; the multi-cylinder branch channel in the bearing tube realizes the isolated transmission of sensor data and servo control signals, ensuring signal integrity; the connector mounting position provides an external output channel for assembly torque and stress data, supporting process parameter optimization and defect root cause analysis; through the above structural design, a full-process assembly data chain is constructed to support digital quality traceability.

[0046] 4、The application designs five-stage screwing control, including fusion laser positioning, gradient speed regulation, pulse screwing and other actions, balancing efficiency and safety; when the ceramic strain exceeds the threshold, reverse rotation is triggered preferentially, and speed reduction is executed when the stress distribution is abnormal, realizing collaborative management of multiple risk scenarios; through the above design, the inherent contradiction of traditional tooling "sacrificing efficiency to ensure safety" is broken through. BRIEF DESCRIPTION OF DRAWINGS

[0047] In order to more clearly illustrate the technical solutions of the embodiments of the application, the following will briefly introduce the drawings needed to be used in the embodiment description. Obviously, the drawings in the following description are only some embodiments of the application, and for those skilled in the art, other drawings can also be obtained without creative labor. Among them:

[0048] Figure 1 It is a schematic diagram of the overall structure of the application.

[0049] Figure 2 It is a schematic diagram of the bottom structure of the application.

[0050] Figure 3 It is a schematic diagram of the front structure of the application.

[0051] Figure 4 It is a schematic diagram of the cross-sectional structure of the application.

[0052] Figure 5 It is a control logic block diagram of the rotation driving module and the state monitoring module of the application.

[0053] Figure 6 It is a work flow chart of the intelligent loss prevention method of the application.

[0054] In the figure: 100, rotation driving module; 101, servo motor; 102, rotating sleeve;

[0055] 200, buffer guiding module; 201, rubber sleeve; 201a, inner elastic buffer layer; 201b, outer rigid guiding layer;

[0056] 300, torque control module;

[0057] 400, anti-overturning module; 401, annular limiting protrusion; 402, guide joint;

[0058] 500, bearing tube module; 501, bearing tube; 502, connector installation site; 503, installation support; 504, wire joint;

[0059] 600, state monitoring module; 601, piezoelectric film sensor; 602, fiber grating sensor;

[0060] 700, modular adaptation mechanism; 701, quick-change interface; 702, adaptation ring. DETAILED DESCRIPTION

[0061] In order to make the above objectives, features and advantages of the present application more apparent, a detailed description of the specific embodiments of the present application will be given below with reference to the accompanying drawings.

[0062] In the following description, a large number of specific details are set forth in order to provide a thorough understanding of the present application, but the present application can also be implemented in other ways different from those described herein, and those skilled in the art can make similar generalizations without departing from the spirit of the present application, so the present application is not limited to the specific embodiments disclosed below.

[0063] Secondly, the "one embodiment" or "embodiment" referred to herein means that the specific features, structures or characteristics can be included in at least one implementation of the present application. "In one embodiment" appearing in different places in the specification does not mean the same embodiment, nor is it an independent or alternative embodiment that excludes other embodiments.

[0064] Thirdly, the present application is described in detail in conjunction with the schematic diagram, and in the detailed description of the embodiments of the present application, the cross-sectional view of the device structure is partially enlarged without the general proportion for the convenience of description, and the schematic diagram is only an example, which should not limit the scope of protection of the present application. In addition, three-dimensional spatial dimensions including length, width and depth should be included in actual manufacture.

[0065] Embodiment 1

[0066] Reference Figures 1-5 For the first embodiment of the present application, a ceramic spark plug high polymer buffer rubber sleeve rotary assembly tool is provided, which includes the following modules for cooperative operation:

[0067] Bearing tube module 500:

[0068] An aluminum alloy tubular bearing tube 501 is adopted, and the servo motor 101 can be fixed in the inner cavity of the bearing tube 501 through a flange.

[0069] The top end of the bearing pipe body 501 is provided with a connector mounting position 502 for connecting the external PLC system to transmit torque data.

[0070] Four wire distribution channels are arranged in the bearing pipe body 501 to correspond to the four-cylinder engine, and the channels are provided with servo motor power lines and sensor signal lines.

[0071] A threaded wire joint 504 is mounted on the side wall of the middle part of the bearing pipe body 501.

[0072] A mounting bracket 503 is welded at the bottom of the bearing pipe body 501, and the mounting bracket 503 is provided with mounting holes for fixing the tooling by bolts.

[0073] Rotary drive module 100:

[0074] The output shaft of the servo motor 101 is connected to a steel rotary sleeve 102, and the end of the rotary sleeve 102 is processed with external splines for torque transmission.

[0075] Buffering and guiding module 200:

[0076] The top end of the high-molecular composite rubber sleeve 201 is connected to the rotary sleeve 102.

[0077] The inner elastic buffer layer 201a of the rubber sleeve is made of solid rubber material, covering the ceramic part of the spark plug; the outer rigid guiding layer 201b is made of hard PVC plastic.

[0078] Torque control module 300:

[0079] The input end of the magneto-rheological coupling is engaged with the splines of the rotary sleeve 102, and the output end is connected to the rubber sleeve 201.

[0080] The dynamic torque controller adjusts the magnetic field strength of the magneto-rheological coupling through the wire.

[0081] Anti-over-tightening module 400:

[0082] The annular limiting protrusion 401 is made of nylon material and is integrally formed at the end of the rubber sleeve 201.

[0083] The protrusion bottom is embedded with a stainless steel guide joint 402, and the inner taper angle is designed to guide the spark plug thread.

[0084] State monitoring module 600:

[0085] The piezoelectric film sensor 601 is pasted on the inner surface of the buffer layer 201a.

[0086] The fiber Bragg grating sensor 602 is glued and fixed along the axial direction of the rubber sleeve 201.

[0087] In actual use: the servo motor 101 drives the rotating sleeve 102, and the torque is transmitted to the rubber sleeve 201 through the magneto-rheological coupling buffer, in the process of rotating the spark plug into the engine cylinder cover, the piezoelectric film sensor 601 monitors the stress on the surface of the ceramic body of the spark plug, and the optical fiber sensor 602 monitors the micro-strain; when the annular limiting protrusion 401 contacts the cylinder cover plane, the servo motor 101 stops working.

[0088] Embodiment 2

[0089] Referring to Figure 3 For the second embodiment of the application, which is different from the first embodiment, the following optimizations are made on the basis of embodiment 1:

[0090] The inner elastic buffer layer 201a adopts micro-porous polyurethane to provide high damping characteristics.

[0091] The outer rigid guide layer 201b adopts glass fiber reinforced engineering plastic.

[0092] The piezoelectric film sensor 601 is embedded in the inner elastic buffer layer 201a in an array.

[0093] The fiber Bragg grating sensor 602 is arranged equidistantly along the axis of the rubber sleeve 201.

[0094] Modular adaptation:

[0095] The rubber sleeve top end is provided with a quick-change interface 701, which adopts a threaded structure.

[0096] The adapter ring 702 provides two specifications of M12x1.25 / M14x1.25, and the inner wall is processed with anti-slip lines.

[0097] When assembling the M14 spark plug, the corresponding adapter ring 702 is selected and clamped into the quick-change interface 701, the glass fiber reinforced outer layer ensures the screwing rigidity, the micro-porous polyurethane layer absorbs the radial impact, and the fiber sensor 602 real-time feedbacks the axial deformation amount of the spark plug ceramic body to the control system.

[0098] Embodiment 3

[0099] Referring to Figures 1-2 For the second embodiment of the application, which is different from the first embodiment, the following optimizations are made on the basis of the above-mentioned embodiment:

[0100] Anti-over-tightening mechanism:

[0101] The outer diameter of the annular limiting protrusion 401 is greater than that of the standard spark plug hexagonal part.

[0102] The annular limiting protrusion 401 can integrate sensors, generate tactile feedback ≥5N when contacting the cylinder cover, and cut off the power supply of the servo motor 101.

[0103] After the spark plug is screwed in the late stage, the annular limiting protrusion 401 contacts the cylinder head, and the tactile feedback triggers the servo motor 101 to stop urgently.

[0104] Embodiment 4

[0105] Reference Figures 5-6 For the second embodiment of the application, which is different from the first embodiment, the embodiment provides an intelligent damage prevention method for the ceramic spark plug high polymer buffer sleeve rotary assembly tool of the above embodiments 1-3. In the embodiment, the assembly tool specifically includes:

[0106] The piezoelectric film sensor array 601: 24 measuring points are arranged in a ring shape, uniformly distributed, with a measuring point spacing of 5 mm, a pressure measurement accuracy of ±0.05 MPa, a response time of not more than 1 ms, and used for real-time monitoring of stress distribution of each part of the ceramic body surface of the spark plug.

[0107] The fiber grating sensor 602: three measuring points are arranged equidistantly along the sleeve 201 axis, with a range of ±2000 micro-strain and a resolution of 1 micro-strain, and used for high-precision sensing of ceramic micro-strain.

[0108] Laser ranging equipment: can be arranged at the front end of the tool (not shown in the figure), with a working distance of 50 to 100 mm and a positioning accuracy of ±0.05 mm, and used for high-precision pre-alignment of the spark plug and the cylinder head threaded hole.

[0109] The execution layer includes key execution mechanisms such as servo motors and magnetorheological couplings:

[0110] Servo motor 101: rated output torque is 30 N·m, speed range is 0 to 300 rpm, acceleration and deceleration response time is less than or equal to 10 ms, and dynamic response type rotation control can be realized.

[0111] Magnetorheological coupling 301: with an output torque adjustment range of 0 to 25 N·m, a magnetic field response time of less than or equal to 5 ms, used for high-precision torque output adjustment, and cooperating with a dynamic controller to respond to micro-strain changes in the assembly process.

[0112] Dynamic torque controller: uses a control chip based on ARM Cortex-M7 architecture, and is equipped with a real-time operating system (RTOS) to realize real-time data acquisition, filtering calculation, compensation instruction execution and other functions.

[0113] Priority arbitration part: uses a hardware interrupt channel allocation mechanism, in which the highest priority is strain threshold value trigger reverse rotation, the intermediate priority is stress distribution unevenness threshold trigger speed reduction, and the basic priority is rotation speed increase in the threaded screwing process.

[0114] The intelligent anti-damage method of the ceramic spark plug high polymer buffer rubber sleeve rotary assembly tooling realized based on the above assembly tooling includes the following stages:

[0115] S1: pre-alignment stage: the tooling is moved to a position 30 mm above the cylinder head threaded hole, and the laser ranging device is started to scan the hole center coordinate; when the current X, Y and Z three-axis positioning errors are all less than or equal to ±0.05 mm, it is determined that the positioning is successful, and the next stage is entered.

[0116] S2: initial screwing-in stage: the servo motor 101 is operated at a speed of ≤50 rpm, the torque is limited to ≤5 N·m, and the torque rising slope is ≤2 N·m / s.

[0117] S3: threaded engagement stage: after entering this stage, the control system performs the following operations:

[0118] S31: speed promotion:

[0119] The screwing-in speed is gradually and smoothly promoted from the current speed to the basic screwing-in speed to avoid the impact on the ceramic body caused by the step response; the basic speed range is set to 100-150 rpm;

[0120] S32: dynamic torque compensation algorithm:

[0121] S321: 1000 micro-strain signals are collected per second;

[0122] S322: signals from the fiber Bragg grating sensor 602 are collected at a frequency of 1 kHz, and denoising processing is performed through a second-order zero-phase Butterworth filter with a cutoff frequency of 100 Hz;

[0123] S323: real-time strain ε1 is output in real time through the fiber Bragg grating sensor 602, and the target strain threshold ε2 is calculated according to the following formula:

[0124] ε2 = σ2 / E;

[0125] Wherein, σ2 = 8 MPa, and E is the elastic modulus of the ceramic body (typical value 350 GPa);

[0126] S324: according to the real-time measured ε1 and the target strain difference threshold ε2 of each sampling period, the torque correction amount is calculated through the following formula:

[0127] ΔT = K c × (ε2-ε1);

[0128] Wherein, the compensation gain K c ∈ [0.1, 0.5], unit: N·m / με;

[0129] The typical value of K c is 0.3 N·m / με;

[0130] S325: When ε1> ε2, then drive the servo motor 101 to rotate reversely at 50% of the current speed for 0.1s to quickly release the local stress;

[0131] When the reverse rotation is triggered, the dynamic torque controller forcibly interrupts other control instructions, prioritizes the 0.1s reverse rotation action, and automatically resets to the current stage basic speed of 100-150rpm after the end;

[0132] It is worth noting that the 0.1s reverse rotation time is based on the stress relaxation time constant of the ceramic body, which is the stress relaxation time constant τ of the ceramic body material, where η is the viscosity modulus of the ceramic body, and E is the elastic modulus of the ceramic body; The typical value is τ ≈ 0.0034s; The reverse rotation time is selected as 0.1s, which is about 30 times the time constant τ, which can ensure that the stress is released sufficiently and avoid the accumulation of micro-cracks;

[0133] S33: Stress unevenness regulation mechanism:

[0134] S331: Real-time calculation of the spark plug ceramic body surface stress distribution unevenness U measured by all piezoelectric film sensors 601:

[0135]

[0136] Where, σ i is the spark plug ceramic body surface stress value detected by the i-th piezoelectric film sensor 601, with the unit of MPa;

[0137] is the average value of the spark plug ceramic body surface stress detected by each piezoelectric film sensor 601;

[0138] S332: When the piezoelectric film sensor 601 array of the state monitoring module 600 detects that the spark plug ceramic body surface stress distribution unevenness U> 20%, the rotation speed of the servo motor 101 in this stage is reduced by 30%, and then restored to the current stage basic speed of 100-150rpm after 2s;

[0139] Considering that the pitch of the spark plug is generally 1.25mm, at a basic speed of 150rpm, a single circle takes 0.4s, and after the speed is reduced to 105rpm, a single circle takes about 0.57s, and a continuous speed reduction of 2s is equivalent to about 3.5 circles of rotation, which can complete the automatic adjustment of the partial load; When the speed reduction amplitude is 30%, the stress unevenness improvement rate can reach 68%, which is better than the industry control target of 60%, and can also consider the assembly time optimization;

[0140] S34: Priority arbitration mechanism:

[0141] If the strain threshold and stress non-uniformity are exceeded at the same time, the system responds to the strain trigger first, and then executes the speed reduction operation after the reverse action is completed.

[0142] Each event has automatic reset logic to prevent system misjudgment or loss of control caused by nested responses.

[0143] S4: Critical torque phase:

[0144] When the torque sensor detects that the output torque reaches 15-18 N·m during assembly, it is judged that it has entered the critical thread locking interval, and the servo motor is triggered to enter the "pulse spin-in mode", that is, it alternately executes 200 ms forward rotation and 100 ms pause every cycle, and executes a maximum of 10 cycles or ends when the maximum torque limit is reached.

[0145] S5: Final tightening lock phase:

[0146] The triggering condition for this phase is that the annular limiting protrusion 401 contacts the cylinder cover plane, and the contact pressure value is greater than or equal to 50 N. The system immediately cuts off the power supply of the servo motor 101 and terminates rotation.

[0147] Through 10,000 sample tests (test model: NGK LFR5A spark plug, cylinder cover material: aluminum-silicon-magnesium alloy (AlSi10Mg)) on an automobile engine assembly line, the data statistics are shown in the following table:

[0148] Index Traditional tooling Tooling of the invention Lifting amplitude Ceramic breakage rate 3.2％ 0.18％ Reduced by 94.4% Assembly concentricity deviation ±0.15 mm ±0.04 mm Reduced by 73.3% Single piece assembly time 8.7s 7.1s Shortened by 18.4% Thread damage rate 1.8％ 0.05％ Reduced by 97.2%

[0149] From the above table, we can see that:

[0150] 1. The ceramic breakage rate of the traditional tooling is as high as 3.2%, mainly due to torque overshoot or unbalanced load leading to instantaneous fracture of brittle ceramic (elastic modulus E = 350 GPa).

[0151] The present application uses a dynamic torque compensation algorithm to monitor the micro-strain data output by the fiber Bragg grating sensor 602 in real time. When the strain value exceeds the threshold value ε2 = σ2 / E, the servo motor 101 is immediately triggered to rotate in reverse at 50% of the current speed for 0.1 seconds, rapidly releasing the local stress. This mechanism reduces the ceramic breakage rate to 0.18%, a decrease of 94.4%, solving the problem of ceramic brittle fracture during spark plug assembly.

[0152] 2. The traditional assembly method is prone to overheating and seizure of the threaded pair due to continuous rotation, with a damage rate of 1.8%.

[0153] The application adopts a pulse rotation mode, switches to 200 ms forward rotation and 100 ms pause alternation operation in the critical torque stage (15-18 N·m) to effectively reduce the accumulation of friction heat, and simultaneously avoids the thread deformation caused by uneven load through stress unevenness regulation (30% speed reduction when U>20%) to finally optimize the thread damage rate to 0.05%, with a 97.2% reduction, and significantly prolong the cylinder cover thread life.

[0154] 3. The assembly concentricity deviation of the traditional tooling is ±0.15 mm, which is difficult to meet the stringent requirements (≤±0.05 mm) of the spark plug positioning of the direct injection engine in the cylinder.

[0155] The application realizes real-time calculation of stress distribution unevenness U through laser pre-positioning (±0.05 mm) and 24-point piezoelectric film sensor array monitoring, and automatically adjusts the speed when U>20% to ensure that the spark plug axis coincides with the center of the thread hole. The measured concentricity deviation is reduced to ±0.04 mm, the precision is improved by 73.3%, and the high-precision engine assembly requirements are perfectly met.

[0156] 4. The traditional tooling has a conservative control strategy (≤50 rpm throughout the process), and the single-piece assembly takes 8.7 seconds.

[0157] The application dynamically optimizes the speed within the safety threshold:

[0158] The initial rotation-in stage (≤50 rpm) avoids uneven load;

[0159] The thread engagement stage adopts an exponential curve speed-up, with a maximum of 150 rpm;

[0160] The critical torque stage balances efficiency and safety through pulse mode.

[0161] The final single-piece assembly time is shortened to 7.1 seconds, with an efficiency improvement of 18.4%, and according to the calculation of 500,000 engines per year, 2200 hours of work time can be saved.

[0162] The application synchronously solves the three technical bottlenecks of ceramic protection, assembly precision and efficiency improvement through the innovative design of “material property quantitative control + multi-sensor fusion (strain + stress monitoring) + hierarchical response arbitration (reverse rotation → speed reduction → pulse mode)”.

[0163] Note: The above data are based on the test results of NGK LFR5A spark plug and AlSi10Mg cylinder cover, and the specific parameters can be adjusted according to different models.

[0164] It should be noted that the above examples are only used to illustrate the technical solutions of the present application but not limit the present application. Although the present application is described in detail with reference to the preferred embodiments, those skilled in the art should understand that the technical solutions of the present application can be modified or equivalently replaced, without departing from the spirit and scope of the technical solutions of the present application, which should be covered in the scope of the claims of the present application.

Claims

1. A rotary assembly fixture for ceramic spark plug polymer buffer sleeves, characterized in that: include: A rotary drive module (100) includes a servo motor (101) and a rotary sleeve (102) driven by it; The buffer guide module (200) includes a rubber sleeve (201) coaxially connected to the rotating sleeve (102). The rubber sleeve (201) is composed of an inner elastic buffer layer (201a) and an outer rigid guide layer (201b). The inner elastic buffer layer (201a) covers the spark plug ceramic body. The torque control module (300) includes a magnetorheological coupling disposed between the rotating sleeve (102) and the rubber sleeve (201), which is connected to a dynamic torque controller; the dynamic torque controller executes a dynamic torque compensation algorithm to correct the output torque in real time based on the micro-strain data of the spark plug ceramic body detected by the fiber optic grating sensor (602); The anti-over-tightening module (400) includes an annular limiting protrusion (401) disposed at the end of the rubber sleeve (201), and a guide joint (402) is arranged at the bottom of the annular limiting protrusion (401). The status monitoring module (600) includes a piezoelectric thin film sensor (601) embedded in an inner elastic buffer layer (201a) and a fiber optic grating sensor (602) disposed on the inner wall of the sleeve (201).

2. The rotary assembly tooling for the ceramic spark plug polymer buffer sleeve as described in claim 1, characterized in that: The inner elastic buffer layer (201a) is made of a microporous high-damping elastic material, and the outer rigid guide layer (201b) is made of glass fiber reinforced engineering plastic.

3. The rotary assembly tooling for ceramic spark plug polymer buffer sleeves as described in claim 2, characterized in that: The outer diameter of the annular limiting protrusion (401) of the anti-over-tightening module (400) is larger than the size of the spark plug hexagonal part. When the annular limiting protrusion (401) contacts the cylinder head plane, it generates tactile feedback and triggers the servo motor (101) to cut off power. The cone angle of its bottom guide joint (402) matches the spark plug thread guide angle.

4. The rotary assembly tooling for ceramic spark plug polymer buffer sleeves as described in claim 3, characterized in that: It also includes a modular adapter mechanism (700), which includes a quick-change interface (701) located at the top of the rubber sleeve (201) and a detachable adapter ring (702), the inner diameter of which matches different spark plug specifications.

5. The rotary assembly tooling for ceramic spark plug polymer buffer sleeves as described in claim 4, characterized in that: It also includes a support tube module (500), which includes a support tube (501), a servo motor (101) arranged inside the support tube (501), and a connector mounting position (502) for connecting the monitoring torque of the equipment is provided at one end of the support tube (501).

6. The rotary assembly tooling for ceramic spark plug polymer buffer sleeves as described in claim 5, characterized in that: The bearing tube (501) is provided with a multi-cylinder branching channel inside. The bearing tube (501) is provided with a wire connector (504) for wire access. The bearing tube (501) is provided with a mounting bracket (503) for fixing and adjusting the position of the tooling equipment.

7. The rotary assembly tooling for ceramic spark plug polymer buffer sleeves as described in claim 6, characterized in that: The piezoelectric thin film sensors (601) of the condition monitoring module (600) are arranged in an array to collect the stress distribution data on the surface of the spark plug ceramic body in real time; the fiber optic grating sensor (602) is arranged along the axial direction of the rubber sleeve (201) to monitor the micro-strain of the spark plug ceramic body.

8. An intelligent anti-damage method for a rotary assembly fixture for ceramic spark plug polymer buffer sleeves, applied to the rotary assembly fixture for ceramic spark plug polymer buffer sleeves as described in any one of claims 1-7, characterized in that: Includes the following stages: Pre-alignment stage: Spark plug and cylinder head threaded holes are aligned using laser equipment; Initial screwing stage: The servo motor (101) runs at a speed of ≤50rpm, the torque limit is ≤5N·m, and the torque rise slope is ≤2N·m / s; During the thread engagement stage: the dynamic torque compensation algorithm is activated, and the speed is increased to 100-150 rpm; Critical torque stage: When the torque reaches 15-18 N·m, switch to a pulse mode that alternates between 200ms forward rotation and 100ms pause; Final tightening and locking stage: After the annular limit protrusion (401) contacts the cylinder head plane, the power supply to the servo motor (101) is cut off.

9. The intelligent anti-damage method for the rotary assembly fixture of ceramic spark plug polymer buffer sleeve as described in claim 8, characterized in that: The dynamic torque compensation algorithm includes the following steps: The signal from the fiber Bragg grating sensor (602) is acquired and denoised. The real-time strain ε1 is output by the fiber optic grating sensor (602), and the target strain threshold ε2 is calculated using the following formula: ε2=σ2 / E; Where σ2=8MPa, and E is the elastic modulus of the ceramic body; Based on the real-time measured ε1 and the target strain difference threshold ε2 for each sampling period, the torque correction is calculated using the following formula: ΔT=K c ×(ε2-ε1); Wherein, the compensation gain K c ∈[0.1, 0.5], unit: N·m / με; When ε1>ε2, the servo motor (101) is driven to rotate in the opposite direction for 0.1s at 50% of the current speed to quickly release local stress. When reverse rotation is triggered, the dynamic torque controller forcibly interrupts other control commands and prioritizes the execution of the 0.1s reverse rotation action. After the action is completed, it automatically resets to the current stage base speed of 100-150rpm.

10. The intelligent anti-damage method for the rotary assembly fixture of the ceramic spark plug polymer buffer sleeve as described in claim 9, characterized in that: During the thread engagement stage, when the piezoelectric thin film sensor (601) array of the condition monitoring module (600) detects that the non-uniformity of the stress distribution on the surface of the spark plug ceramic body U>20%, the screwing speed of the servo motor (101) in this stage is reduced by 30%, and after 2 seconds it is restored to the base speed of the current stage of 100-150 rpm. The formula for calculating the surface stress non-uniformity U of the spark plug ceramic body is as follows: Where, σ i The value of the surface stress of the spark plug ceramic body detected by the i-th piezoelectric thin film sensor (601) is expressed in MPa. The average surface stress of the spark plug ceramic body detected by each piezoelectric thin film sensor (601) is the average value.

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