Assembly method of interference fit hinge

Abstract

The invention relates to an assembly method of an interference fit hinge, and belongs to the technical field of mechanical connection.The interference fit hinge comprises a shaft body, a shaft seat and a plurality of butterfly-shaped elastic pieces, and the shaft seat and the butterfly-shaped elastic pieces are fixed through connecting pieces and can be connected to the shaft body in a sleeving mode in a relatively rotating mode; the butterfly-shaped elastic piece and the shaft seat are in interference fit to generate damping force, and an oil storage groove formed in the butterfly-shaped elastic piece is used for being filled with lubricating oil so as to provide the lubrication degree when the shaft seat and the butterfly-shaped elastic piece rotate relatively. The assembly method comprises the steps of laser-assisted shaft seat positioning, gradient pressure hinge assembly, lubricating oil injection, damping torque signal acquisition, signal filtering and PID algorithm adjustment, laser-assisted positioning is used for guaranteeing the precision of the assembly position, the damping torque signal standard deviation of the currently assembled hinge is monitored in real time, the PID algorithm is used for dynamically adjusting follow-up assembly parameters, and the precision of the assembly position is guaranteed. And stable and consistent assembly quality of the hinge is ensured. Therefore, assembly errors caused by fluctuation of machining parameters can be reduced, and the overall precision of products is improved.

Description

Technical Field

[0001] The invention relates to the technical field of mechanical connection, and in particular to an assembly method of an interference fit hinge. Background Art

[0002] Traditional hinge structures mostly use bolts and spring sheets to achieve damping, and rely on manual experience to adjust the bolt preload. Different operators have different adjustment techniques and strengths, resulting in large fluctuations in friction torque and inconsistent user experience. Secondly, the damping control process of the hinge is complicated and time-consuming, requiring professional personnel, and the adjustment process may require multiple trial and error, which increases maintenance costs and time. The bolts and spring sheets are prone to wear during long-term use, resulting in a decrease in the damping effect and shortening the service life of the hinge. In addition, the assembly parameters of traditional hinges rely on manual experience to adjust, and it is difficult to ensure the position accuracy of the hinge and the uniformity of the damping torque, which will lead to unstable hinge assembly quality and affect the overall performance of the product. Traditional hinge assembly methods are difficult to adapt to different working environments, load conditions and workpiece sizes.

[0003] In view of the above situation, there is an urgent need to design an assembly method for an interference fit hinge. Summary of the invention

[0004] In view of the deficiencies mentioned in the above technical background, an object of the present invention is to provide an assembly method of an interference fit hinge.

[0005] The purpose of the present invention can be achieved through the following technical solutions: An assembly method of an interference fit hinge comprises the following steps: S1. Laser-assisted positioning interference fit hinge: The interference fit hinge is used to achieve a pivotal connection between a fixed part and a movable part, and includes a shaft body, a shaft seat and a plurality of butterfly-shaped spring pieces; the shaft body is fixedly connected to the fixed part and is relatively rotatably connected to the movable part; the shaft seat is fixedly connected to the movable part, and an shaft hole is provided at one end of the shaft seat, and the shaft body can be relatively rotatably inserted into the shaft hole; a connecting hole is provided at one end of the butterfly-shaped spring piece, and the shaft body can be relatively rotatably inserted into the connecting hole, and the diameter of the connecting hole is smaller than the diameter of the shaft body, so that there is an interference fit between the butterfly-shaped spring piece and the shaft body; the other end of the butterfly-shaped spring piece is fastened to the shaft seat through a connecting piece, and a plurality of oil storage grooves are provided on the inner wall of the butterfly-shaped spring piece, and the oil storage grooves are filled with lubricating oil to provide lubrication when the fixed part and the movable part rotate relative to each other; Use a laser projector to project the designed shaft hole point of the shaft seat onto the work surface, align and place the shaft hole of the shaft seat according to the designed shaft hole point, and fix the position of the shaft seat with a clamp; S2, gradient pressure assembly hinge: the butterfly spring is fastened to the shaft seat through the connecting piece, and the servo press is used to apply pressure in stages to sequentially insert the shaft body into the connecting hole of the butterfly spring, the shaft hole of the shaft seat, the movable part and the fixed part, and the axial displacement and pressure of the shaft body are monitored in real time by using a displacement sensor and a force sensor, and the coaxiality is automatically calibrated by using laser alignment technology, wherein the butterfly spring, the shaft seat and the movable part are all connected to the shaft body in a relatively rotatable manner, and the fixed part is fixedly connected to the end of the shaft body, thereby completing the assembly of the interference fit hinge; S3, lubricating oil injection: inject a set amount of lubricating oil into the oil storage tank through a micro-metering pump, and use an ultrasonic sensor to detect the oil level, and trigger an alarm when the oil level exceeds the tolerance; S4. Damping torque signal acquisition: After assembly, the interference fit hinge is rotated at a constant speed by a servo motor, and the original damping torque signal X of the entire rotation process is acquired by a non-contact torque sensor installed between the servo motor and the interference fit hinge at a set frequency f. i (i=1, 2....n), n is the number of collected signals; S5, signal filtering: the original damping torque signal X i Perform sliding average filtering to obtain the filtered damping torque signal M k , eliminate high-frequency noise and draw the damping torque curve, and calculate the filtered damping torque signal M k The standard deviation SD(t) is calculated and compared with the set standard deviation threshold SD' to evaluate whether the assembly quality of the interference fit hinge is qualified; S6, PID algorithm adjustment: According to the extent to which the standard deviation SD(t) exceeds the set standard deviation threshold SD', the PID algorithm is used to calculate the next adjustment target of the interference fit hinge, and the pressure application speed v of the servo press is adjusted until the damping torque signal M k The standard deviation SD(t) meets the requirements.

[0006] As a preferred technical solution of the present invention, the type of clamp in step S1 is selected according to the material properties of the shaft seat, including magnetic clamping, mechanical clamping or vacuum adsorption clamp.

[0007] As a preferred technical solution of the present invention, in step S2, the servo press applies pressure in three stages, specifically, an initial centering stage, a main body pressing stage, and a final pressure stage. The initial centering stage applies 5% of the rated pressure, the main body pressing stage applies 50%-80% of the rated pressure at a uniform speed, and the final pressure stage applies 100% of the rated pressure and maintains the pressure for more than 2 seconds.

[0008] As a preferred technical solution of the present invention, the sampling frequency f of the non-contact torque sensor is ≥ 1 kHz, and the set standard deviation threshold is 0.2 N·m.

[0009] As a preferred technical solution of the present invention, the sliding average filtering process in step S5 is specifically as follows: caching the first N original damping torque signals X1, X2...X N , calculate the first filtered damping torque signal M N :

[0010] Every time a new original damping torque signal X is collected k , add it to the window queue, and remove the oldest original damping torque signal X in the window k−N+1 , the arithmetic mean of the N data in the calculation window is updated to the filtered damping torque signal M k , the filtered damping torque signal M k The following relationship is satisfied:

[0011] Where M k is the damping torque signal after the kth filter, N is the size of the sliding window, X i is the i-th original damping torque signal; When the number of original damping torque signals Xi collected in the initial stage is less than N, that is, k<N, the filtered damping torque signal M in the initial stage is obtained by partial averaging. k , satisfying the following relationship:

[0012] As a preferred technical solution of the present invention, the PID algorithm in step S6 controls the pressure application speed v of the servo press, specifically comprising the following steps: S61, calculating the error value between the standard deviation SD(t) and the set standard deviation threshold SD': e(t)=SD(t)−SD' When e(t) < 0, no PID optimization is required. The current damping torque signal M k The standard deviation SD(t) meets the requirements; when e(max)≥e(t)>0, enter step S62 to perform PID optimization and continue monitoring; when e(t)>e(max), immediately stop the adjustment operation of the current interference fit hinge and the subsequent assembly operation of the interference fit hinge, and check whether the interference between the shaft body and the butterfly spring meets the design requirements; The over-limit threshold of the error value e(t) is set to e(max), that is, the actual interference between the shaft body and the butterfly spring of the current interference fit hinge exceeds the design threshold, which will cause component damage or assembly failure. Therefore, it is necessary to immediately stop the adjustment and assembly operations and check whether the dimensions of the shaft body and the butterfly spring are qualified; S62, Initialize PID parameters: Initialize and set the parameters of the PID control algorithm, including the proportional constant K p , integration constant K i , differential constant K d ; S63, calculate the control quantity according to the PID control algorithm:

[0013] Where, Output(t) is the PID output value, K p is the proportionality constant, K i is the integration constant, K d is the differential constant; S64, adjusting the pressure application speed: adjusting the pressure application speed v of the servo press according to the PID output value Output(t); S65, real-time monitoring and feedback: real-time monitoring of the standard deviation SD of the damping torque signal, and feedback to the PID controller for closed-loop control. According to the actual control effect, the parameter K of the PID control algorithm is gradually adjusted. p , K i and K d , in order to achieve the best control effect.

[0014] As a preferred technical solution of the present invention, a plurality of arc-shaped interference blocks are provided on the inner wall of the connecting hole, the shaft body is relatively rotatably arranged on the arc-shaped interference blocks, the contact surface between the arc-shaped interference blocks and the shaft body is an interference fit surface, and the oil storage tank is formed between adjacent arc-shaped interference blocks.

[0015] As a preferred technical solution of the present invention, an opening is provided on one side of the connecting hole, and the arc-shaped interference blocks are provided on both left and right ends of the opening close to the inner wall of the connecting hole.

[0016] As a preferred technical solution of the present invention, the butterfly-shaped spring piece is made of elastic material; the shaft body is a bolt structure, and the shaft body and the fixing part are fixed by connecting and fixing the nut with the threaded teeth and flat knurled structure at the end of the bolt structure; the connecting part is a rivet structure.

[0017] In summary, the beneficial effects of the present invention are: The interference fit hinge of the present invention utilizes the interference fit between the butterfly spring piece and the shaft body to generate a damping torque, providing a more stable connection and significantly reducing the occurrence of friction and loosening during movement. Compared with the traditional bolt and spring sheet structure, its wear after long-term use is much lighter. Due to the less wear, its damping effect can be maintained at a good level for a long time, thereby extending the service life of the hinge. In addition, the interference fit hinge of the present invention has good adaptability in different working environments. Whether it is under high temperature, low temperature, or high humidity and other harsh environmental conditions, the interference fit structure between the butterfly spring piece and the shaft body can still play a stable role and ensure the stable output of the damping torque, thereby maintaining the normal working state of the hinge. The structural reliability is relatively high. During frequent opening and closing operations, it can effectively avoid failures caused by looseness or excessive wear, further improving the overall durability and safety of the product.

[0018] The assembly method of the present invention quantitatively evaluates the assembly quality of the current interference fit hinge by calculating the error value e(t) between the standard deviation SD(t) and the set standard deviation threshold SD'. The standard deviation is an important indicator for measuring the degree of signal fluctuation and reflects the damping performance of the hinge. According to the size of the error value e(t), the PID algorithm is used to dynamically adjust the assembly parameters. The control quantity Output(t) is calculated through the comprehensive effect of the three links of proportion, integration and differentiation to adjust the pressure application speed v of the servo press, so as to timely discover and correct problems in the assembly process, ensure the assembly quality of subsequent interference fit hinges, and avoid assembly quality problems caused by fixed assembly parameters; secondly, real-time monitoring of the assembly quality of each interference fit hinge helps to improve the transparency of the production process, facilitate quality control and problem tracing, and facilitate the consistency of the quality of the same batch of products. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 It is a schematic diagram of the installation of the interference fit hinge of the present invention; Figure 2 is a schematic diagram of an interference fit hinge of the present invention; Figure 3 is a schematic diagram of the axle seat of the present invention; Figure 4 Schematic diagram of the butterfly-shaped shrapnel of the present invention; Figure 5 It is a plan view of the butterfly-shaped spring piece of the present invention; Figure 6 It is a flow chart of an assembly method of an interference fit hinge of the present invention; In the figure, 1-interference fit hinge, 11-axis body, 12-axis seat, 121-axis hole, 13-butterfly spring, 131-connecting hole, 132-oil storage tank, 133-arc interference block, 134-opening, 14-connecting part, 2-fixed part, 3-movable part. DETAILED DESCRIPTION

[0020] The specific embodiments of the present invention are described in detail below in conjunction with the accompanying drawings. It should be understood that the specific embodiments given here are only used to illustrate and explain the present invention, and cannot be used to limit the present invention.

[0021] It should be noted that many specific details are set forth in the following description to facilitate a full understanding of the present invention. However, the present invention may also have other implementations and variations thereof. Therefore, the protection scope of the present invention is not limited to the specific embodiments disclosed below.

[0022] like Figures 1 to 6 As shown, a method for assembling an interference fit hinge 1 comprises the following steps: S1. Laser-assisted positioning interference fit hinge 1: The interference fit hinge 1 is used to realize the pivot connection between the fixed part 2 and the movable part 3, and includes a shaft body 11, a shaft seat 12 and a plurality of butterfly-shaped spring pieces 13; the shaft body 11 is fixedly connected to the fixed part 2 and is relatively rotatably connected to the movable part 3; the shaft seat 12 is fixedly connected to the movable part 3, and one end of the shaft seat 12 is provided with a shaft hole 121, and the shaft body 11 can be relatively rotatably inserted into the shaft hole 121; one end of the butterfly-shaped spring piece 13 ... one end of the shaft seat 12 is provided with a shaft hole 121, and the shaft body 11 can be relatively rotatably inserted into the shaft hole 121; one end of the butterfly-shaped spring piece 13 is fixedly connected to the fixed part 2 and is relatively rotatably connected to the movable part 3; one end of the butterfly-shaped spring piece 13 is fixedly connected to the fixed part 2 and is relatively rotatably connected to the movable part 3; one end of the butterfly-shaped spring piece 13 is fixedly connected to the movable part 3 and is relatively rotatably connected to the movable part 3; one end of the butterfly-shaped spring piece 13 is fixedly connected to the movable part 3 and is relatively rotatably connected to the movable part 3; one end of the butterfly-shaped spring piece 13 is fixedly connected to the movable part 3 and A connecting hole 131 is provided at the end, and the shaft body 11 can be relatively rotatably inserted in the connecting hole 131. The diameter of the connecting hole 131 is smaller than the diameter of the shaft body 11, so that the butterfly-shaped spring piece 13 and the shaft body 11 are interference-fitted; the other end of the butterfly-shaped spring piece 13 is fastened to the shaft seat 12 through a connecting piece 14, and a plurality of oil storage grooves 132 are provided on the inner wall of the butterfly-shaped spring piece 13. The oil storage grooves 132 are filled with lubricating oil to provide lubrication when the fixed part 2 and the movable part 3 rotate relative to each other; The shaft seat 12 is used to position the movable part 3 and provide holes for connecting the shaft body 11 and the butterfly-shaped spring piece 13; one end of the connecting piece 14 is fixed to the shaft seat 12 and the other end is connected to the base of the butterfly-shaped spring piece 13 to form an axial constraint; the shaft body 11 is axially penetrated into the connecting hole 131 of the butterfly-shaped spring piece 13, and has an interference fit with the butterfly-shaped spring piece 13 to produce adjustable damping, and the end extends to the external fixing part 2, and the end is provided with a screw thread and a flat knurling structure, which is used for threaded connection with the fixing part 2 and anti-loosening fixation; the butterfly-shaped spring piece 13 is located between the shaft seat 12 and the movable part 3, is sleeved on the outer periphery of the shaft body 11 and cooperates with the shaft body 11, provides damping force through elastic deformation, and has a built-in oil storage tank 132 to store lubricating oil, which is used to reduce friction with the shaft body 11, reduce friction noise and extend service life.

[0023] Use a laser projector to project the designed shaft hole point of the shaft seat 12 onto the work surface, align and place the shaft hole 121 of the shaft seat 12 according to the designed shaft hole point, and fix the position of the shaft seat 12 with a fixture; Traditional methods rely on manual marking and positioning, which is prone to errors due to human factors. The present invention uses laser-assisted positioning of the shaft seat 12, and programmed guided operation to avoid human errors, which can ensure that the shaft hole 121 of the shaft seat 12 is accurately aligned with the designed position, with fast positioning speed and high positioning accuracy, reducing human operation errors and improving assembly consistency and reliability. In addition, the laser projection system can adapt to different types of targets, including planes, curved surfaces, transparent objects, small objects or oversized objects, and can quickly and accurately position on complex, special-shaped structural parts or surfaces, improving production flexibility and reducing assembly difficulty caused by the complexity of the workpiece.

[0024] S2, gradient pressure assembly hinge: fasten the butterfly spring piece 13 to the shaft seat 12 through the connecting piece 14, use a servo press to apply pressure in stages to insert the shaft body 11 into the connecting hole 131 of the butterfly spring piece 13, the shaft hole 121 of the shaft seat 12, the movable part 3 and the fixed part 2 in sequence, and use a displacement sensor and a force sensor to monitor the axial displacement and pressure of the shaft body 11 in real time, and use laser alignment technology to automatically calibrate the coaxiality, wherein the butterfly spring piece 13, the shaft seat 12 and the movable part 3 are all connected to the shaft body 11 so that they can rotate relative to each other, and the fixed part 2 is fixedly connected to the end of the shaft body 11, completing the assembly of the interference fit hinge 1; By applying pressure in stages, it is possible to ensure that the interference fit between the shaft body 11 and the butterfly spring piece 13, the shaft seat 12 and the movable part 3 is tighter and more stable, thereby improving the assembly quality, avoiding excessive pressure at one time, and reducing damage to components; the servo press applies pressure in three stages to avoid excessive pressure at one time and reduce damage to components, specifically the initial centering stage, the main body pressing stage and the final pressure stage. In the initial centering stage, 5% of the rated pressure is applied to ensure that the shaft body 11 is aligned with the connecting hole 131 of the butterfly spring piece 13; in the main body pressing stage, 50%-80% of the rated pressure is applied at a uniform speed to ensure that the shaft body 11 is smoothly inserted into the connecting hole 131 of the butterfly spring piece 13, the shaft hole 121 of the shaft seat 12, the movable part 3 and the fixed part 2; in the final pressure stage, 100% of the rated pressure is applied and maintained for more than 2 seconds to ensure the tightness of the interference fit.

[0025] S3, lubricating oil injection: inject a set amount of lubricating oil into the oil storage tank 132 through a micro-metering pump, and use an ultrasonic sensor to detect the oil level, and trigger an alarm when the oil level exceeds the tolerance; S4. Damping torque signal acquisition: After assembly, the interference fit hinge 1 is rotated at a constant speed by a servo motor, and the original damping torque signal X of the entire rotation process is collected by a non-contact torque sensor installed between the servo motor and the interference fit hinge 1 at a set frequency f. i (i=1, 2....n), n is the number of collected signals; S5, signal filtering: the original damping torque signal X iPerform sliding average filtering to obtain the filtered damping torque signal M k , eliminate high-frequency noise and draw the damping torque curve, and calculate the filtered damping torque signal M k The standard deviation SD(t) is calculated and compared with the set standard deviation threshold SD' to evaluate whether the current assembly quality of the interference fit hinge 1 is qualified; S6, PID algorithm adjustment: According to the degree to which the standard deviation SD(t) exceeds the set standard deviation threshold SD', the PID algorithm is used to calculate the adjustment target of the next interference fit hinge 1, and the pressure application speed v of the servo press is adjusted until the damping torque signal M k The standard deviation SD(t) meets the requirements.

[0026] The working principle of the interference fit hinge 1 of the present invention is as follows: when no operating force is applied, static friction is generated between the butterfly spring piece 13 and the shaft body 11 due to the interference fit, and this friction is large enough to prevent the shaft body 11 from rotating on its own when no external force is applied; when the applied operating force exceeds the static friction, the hinge starts to rotate, and the friction resistance generated by the interference fit between the butterfly spring piece 13 and the shaft body 11 becomes the dominant factor. The elastic properties of the material of the butterfly spring piece 13 cause it to produce elastic deformation during the interference fit, resulting in the butterfly spring piece 13 being deformed against the shaft body 11. The shaft 11 generates a continuous normal pressure, that is, a force perpendicular to the surface of the shaft 11. The existence of the normal pressure forms a stable dynamic friction torque between the butterfly spring 13 and the shaft 11. The dynamic friction torque is the torque that hinders the rotation of the shaft 11. Due to the elastic deformation of the butterfly spring 13 and the continuous normal pressure, the hinge can always hold the shaft 11 tightly and maintain close contact even during rotation, thereby providing a stable and controllable damping effect, so that the hinge can absorb energy during rotation, slow down the movement speed, and achieve a damping effect.

[0027] Compared with other types of interference fit hinges 1 on the market, the interference fit hinge 1 of the present invention uses the butterfly spring piece 13 with an internal oil storage tank 132 to complete the interference fit with the shaft body 11, reducing the oil storage gaskets arranged between the butterfly spring pieces 13, reducing the types and number of parts, making the assembly process more convenient, reducing the potential risk of oil leakage of the oil storage gasket, improving the reliability and stability of the hinge, and improving production efficiency; secondly, the oil storage tank 132 is directly arranged on the inner wall of the butterfly spring piece 13 that is interference fit with the shaft body 11, that is, the oil storage tank 132 is directly adjacent to the contact surface between the butterfly spring piece 13 and the shaft body 11, and the lubricating oil can be quickly exchanged between the contact surface and the oil storage tank 132, so as to quickly lubricate the area where the shaft body 11 and the butterfly spring piece 13 complete the relative rotation. Compared with the lubrication method using oil storage gaskets arranged at intervals, the lubrication effect of the present invention can fully cover the interference fit area, ensuring that the contact surface is always in a good lubrication state, making the hinge smoother during use, providing stable damping torque and performance, and having higher cost-effectiveness in long-term use.

[0028] The assembly method of the present invention uses a non-contact torque sensor to collect the damping torque signal of the assembled interference fit hinge 1 in real time, and processes the original damping torque signal through a sliding average filter to eliminate high-frequency noise, more accurately reflect the actual performance of the current interference fit hinge 1, and calculate the standard deviation SD(t) of the damping torque signal after filtering. According to the degree to which the standard deviation SD(t) exceeds the set standard deviation threshold SD', the PID algorithm is combined to calculate the adjustment target of the next interference fit hinge 1. The PID algorithm dynamically adjusts the pressure application speed v of the servo press through the comprehensive effect of the three links of proportion, integration and differentiation until the damping torque signal M k The standard deviation SD(t) meets the requirements. The dynamic control of the assembly process of a batch of interference fit hinges 1 is realized to ensure that the hinges assembled subsequently remain consistent in assembly quality, avoiding the traditional hinge assembly method in which assembly parameters are adjusted based on manual experience. Once quality problems are found, a large number of unqualified hinges have often been produced, which has a very serious lag and leads to waste of resources and increased costs. The assembly method of the present invention can also improve the degree of automation and production efficiency of the entire production process, reduce errors that may be caused by manual intervention, further improve the quality stability of the product, and enhance the competitiveness of the product in the market.

[0029] As a preferred embodiment of the present invention, in step S1 , the type of clamp is selected according to the material properties of the shaft seat 12 , including magnetic clamping, mechanical clamping or vacuum adsorption clamping.

[0030] As a preferred embodiment of the present invention, the sampling frequency f of the non-contact torque sensor is ≥ 1 kHz, and the standard deviation threshold is set to 0.2 N·m.

[0031] As a preferred embodiment of the present invention, the sliding average filtering process in step S5 is specifically as follows: caching the first N original damping torque signals X1, X2, ..., X N , calculate the first filtered damping torque signal M N :

[0032] Every time a new original damping torque signal X is collected k , add it to the window queue, and remove the oldest original damping torque signal X in the window k−N+1 , the arithmetic mean of the N data in the calculation window is updated to the filtered damping torque signal M k , the filtered damping torque signal M k The following relationship is satisfied:

[0033] Where M k is the damping torque signal after the kth filter, N is the size of the sliding window, X i is the i-th original damping torque signal; When the number of original damping torque signals Xi collected in the initial stage is less than N, that is, k<N, the filtered damping torque signal M in the initial stage is obtained by partial averaging. k , satisfying the following relationship:

[0034] In the process of collecting damping torque signals, the original signals will be subject to various interferences, such as mechanical vibration, electromagnetic interference, etc., resulting in high-frequency noise in the signals. These high-frequency noises will affect the accuracy and stability of the signals, and thus affect the evaluation of hinge performance. Through sliding average filtering, high-frequency noise can be effectively eliminated, making the filtered damping torque signal smoother and more stable. The sliding average filter reduces the random error of a single data point by calculating the average value of multiple data points in the window, and reduces signal fluctuations caused by accidental factors. The filtered signal is more reliable and can more truly reflect the damping characteristics of the hinge. This helps to improve the evaluation accuracy of assembly quality and ensure that the performance of each hinge meets the design requirements.

[0035] As a preferred embodiment of the present invention, the PID algorithm in step S6 controls the pressure application speed v of the servo press, which specifically includes the following steps: S61. Calculate the error between the standard deviation SD(t) and the set standard deviation threshold SD': e(t)=SD(t)−SD' When e(t) < 0, no PID optimization is required. The current damping torque signal Mk The standard deviation SD(t) meets the requirements; when e(max)≥e(t)>0, enter step S62 to perform PID optimization and continue monitoring; when e(t)>e(max), immediately stop the adjustment operation of the current interference fit hinge 1 and the subsequent assembly operation of the interference fit hinge 1, and check whether the interference between the shaft body 11 and the butterfly spring 13 meets the design requirements; The over-limit threshold of the error value e(t) is set to e(max), that is, the actual interference between the shaft 11 and the butterfly spring 13 of the current interference fit hinge 1 exceeds the design threshold, which will cause component damage or assembly failure. Therefore, it is necessary to immediately stop the adjustment and assembly operations to check whether the dimensions of the shaft 11 and the butterfly spring 13 are qualified; the over-limit threshold e(max) is the maximum allowable error value between the standard deviation SD(t) and the set standard deviation threshold SD', and the design threshold is the interference design requirement of the interference fit hinge during the assembly process; S62, Initialize PID parameters: Initialize and set the parameters of the PID control algorithm, including the proportional constant K p , integration constant K i , differential constant K d ; S63, calculate the control quantity according to the PID control algorithm:

[0036] Where, Output(t) is the PID output value, K p is the proportionality constant, K i is the integration constant, K d is the differential constant; S64, adjusting the pressure application speed: adjusting the pressure application speed v of the servo press according to the PID output value Output(t); S65, real-time monitoring and feedback: real-time monitoring of the standard deviation SD of the damping torque signal, and feedback to the PID controller for closed-loop control. According to the actual control effect, the parameter K of the PID control algorithm is gradually adjusted. p , K i and K d , in order to achieve the best control effect.

[0037] By calculating the error value e(t) between the standard deviation SD(t) and the set standard deviation threshold SD', the assembly quality of the current interference fit hinge 1 is quantitatively evaluated. The standard deviation is an important indicator to measure the degree of signal fluctuation and reflects the damping performance of the hinge. According to the size of the error value e(t), the PID algorithm is used to dynamically adjust the assembly parameters, where the proportional constant K p Determines the system's response speed to errors, the integral constant K i Static error can be eliminated, differential constant Kd The changing trend of the error can be predicted, and the control quantity Output(t) can be calculated through the comprehensive effect of the three links of proportion, integration and differentiation to adjust the pressure application speed v of the servo press to ensure the subsequent assembly quality of the interference fit hinge 1.

[0038] As a preferred embodiment of the present invention, a plurality of arc-shaped interference blocks 133 are provided on the inner wall of the connecting hole 131 , and the shaft body 11 can be relatively rotatably arranged on the arc-shaped interference blocks 133 . The contact surface between the arc-shaped interference blocks 133 and the shaft body 11 is an interference fit surface, and an oil storage tank 132 is formed between adjacent arc-shaped interference blocks 133 .

[0039] As a preferred embodiment of the present invention, an opening 134 is provided on one side of the connection hole 131 , and arc-shaped interference blocks 133 are provided on both left and right ends of the opening 134 close to the inner wall of the connection hole 131 .

[0040] The left and right ends of the opening 134 are both provided with arc-shaped interference blocks 133 that fit tightly against the inner wall of the connecting hole, forming an effective seal to prevent the lubricating oil from leaking from the opening 134 and ensure the sealing of the structure.

[0041] As a preferred embodiment of the present invention, the butterfly-shaped spring piece 13 is made of elastic material; the shaft body 11 is a bolt structure, and the shaft body 11 and the fixing member 2 are fixedly connected by the screw thread and the flat knurling structure at the end of the nut and the bolt structure; the connecting member 14 is a rivet structure.

[0042] It should be understood that the above-mentioned embodiments are one or more embodiments of the present invention, and there are many other embodiments and variations thereof based on the present invention; the variations and modifications made by ordinary technicians in this industry through the present invention without making pioneering innovations all fall within the scope of protection of the present invention.

Claims

1. A method for assembling an interference fit hinge, characterized in that The following steps are involved: S1. Laser-assisted positioning interference fit hinge: The interference fit hinge is used to achieve a pivotal connection between a fixed part and a movable part, and includes a shaft body, a shaft seat and a plurality of butterfly-shaped spring pieces; the shaft body is fixedly connected to the fixed part and is relatively rotatably connected to the movable part; the shaft seat is fixedly connected to the movable part, and an shaft hole is provided at one end of the shaft seat, and the shaft body can be relatively rotatably inserted into the shaft hole; a connecting hole is provided at one end of the butterfly-shaped spring piece, and the shaft body can be relatively rotatably inserted into the connecting hole, and the diameter of the connecting hole is smaller than the diameter of the shaft body, so that there is an interference fit between the butterfly-shaped spring piece and the shaft body; the other end of the butterfly-shaped spring piece is fastened to the shaft seat through a connecting piece, and a plurality of oil storage grooves are provided on the inner wall of the butterfly-shaped spring piece, and the oil storage grooves are filled with lubricating oil to provide lubrication when the fixed part and the movable part rotate relative to each other; Use a laser projector to project the designed shaft hole point of the shaft seat onto the work surface, align and place the shaft hole of the shaft seat according to the designed shaft hole point, and fix the position of the shaft seat with a clamp; S2, gradient pressure assembly hinge: the butterfly spring is fastened to the shaft seat through the connecting piece, and the servo press is used to apply pressure in stages to sequentially insert the shaft body into the connecting hole of the butterfly spring, the shaft hole of the shaft seat, the movable part and the fixed part, and the axial displacement and pressure of the shaft body are monitored in real time by using a displacement sensor and a force sensor, and the coaxiality is automatically calibrated by using laser alignment technology, wherein the butterfly spring, the shaft seat and the movable part are all connected to the shaft body in a relatively rotatable manner, and the fixed part is fixedly connected to the end of the shaft body, thereby completing the assembly of the interference fit hinge; S3, lubricating oil injection: inject a set amount of lubricating oil into the oil storage tank through a micro-metering pump, and use an ultrasonic sensor to detect the oil level, and trigger an alarm when the oil level exceeds the tolerance; S4. Damping torque signal acquisition: After assembly, the interference fit hinge is rotated at a constant speed by a servo motor, and the original damping torque signal X of the entire rotation process is acquired by a non-contact torque sensor installed between the servo motor and the interference fit hinge at a set frequency f. i (i=1, 2....n), n is the number of collected signals; S5, signal filtering: the original damping torque signal X i Perform sliding average filtering to obtain the filtered damping torque signal M k , eliminate high-frequency noise and draw the damping torque curve, and calculate the filtered damping torque signal M k The standard deviation SD(t) is calculated and compared with the set standard deviation threshold SD' to evaluate whether the assembly quality of the interference fit hinge is qualified; S6, PID algorithm adjustment: According to the extent to which the standard deviation SD(t) exceeds the set standard deviation threshold SD', the PID algorithm is used to calculate the next adjustment target of the interference fit hinge, and the pressure application speed v of the servo press is adjusted until the damping torque signal M k The standard deviation SD(t) meets the requirements.

2. The assembly method of an interference fit hinge according to claim 1, characterized in that: The type of clamp in step S1 is selected according to the material properties of the shaft seat, including magnetic clamping, mechanical clamping or vacuum adsorption clamping.

3. The assembly method of an interference fit hinge according to claim 1, characterized in that: In step S2, the servo press applies pressure in three stages, namely, an initial centering stage, a main body pressing stage, and a final pressure stage. The initial centering stage applies 5% of the rated pressure, the main body pressing stage applies 50%-80% of the rated pressure at a uniform speed, and the final pressure stage applies 100% of the rated pressure and maintains the pressure for more than 2 seconds.

4. The method for assembling an interference fit hinge according to claim 1, characterized in that: The non-contact torque sensor sampling frequency f≥1kHz, and the set standard deviation threshold is 0.2N·m.

5. The assembly method of an interference fit hinge according to claim 1, characterized in that: The sliding average filtering process in step S5 is specifically as follows: caching the first N original damping torque signals X1, X2, ..., X N , calculate the first filtered damping torque signal M N : Every time a new original damping torque signal X is collected k , add it to the window queue, and remove the oldest original damping torque signal X in the window k−N+1 , the arithmetic mean of the N data in the calculation window is updated to the filtered damping torque signal M k , the filtered damping torque signal M k The following relationship is satisfied: Where M k is the damping torque signal after the kth filter, N is the size of the sliding window, X i is the i-th original damping torque signal; When the number of original damping torque signals Xi collected in the initial stage is less than N, that is, k<N, the filtered damping torque signal M in the initial stage is obtained by partial averaging. k , satisfying the following relationship:

6. The method for assembling an interference fit hinge according to claim 1, characterized in that: The PID algorithm in step S6 controls the pressure application speed v of the servo press, which specifically includes the following steps: S61, calculating the error value between the standard deviation SD(t) and the set standard deviation threshold SD': e(t)=SD(t)−SD' When e(t) < 0, no PID optimization is required. The current damping torque signal M k The standard deviation SD(t) meets the requirements; when e(max)≥e(t)>0, enter step S62 to perform PID optimization and continue monitoring; when e(t)>e(max), immediately stop the adjustment operation of the current interference fit hinge and the subsequent assembly operation of the interference fit hinge, and check whether the interference between the shaft body and the butterfly spring meets the design requirements; The over-limit threshold of the error value e(t) is set to e(max), that is, the actual interference between the shaft body and the butterfly spring of the current interference fit hinge exceeds the design threshold, which will cause component damage or assembly failure. Therefore, it is necessary to immediately stop the adjustment and assembly operations and check whether the dimensions of the shaft body and the butterfly spring are qualified; S62, Initialize PID parameters: Initialize and set the parameters of the PID control algorithm, including the proportional constant K p , integration constant K i , differential constant K d ; S63, calculate the control quantity according to the PID control algorithm: Where, Output(t) is the PID output value, K p is the proportionality constant, K i is the integration constant, K d is the differential constant; S64, adjusting the pressure application speed: adjusting the pressure application speed v of the servo press according to the PID output value Output(t); S65, real-time monitoring and feedback: real-time monitoring of the standard deviation SD of the damping torque signal, and feedback to the PID controller for closed-loop control. According to the actual control effect, the parameter K of the PID control algorithm is gradually adjusted. p , K i and K d , in order to achieve the best control effect.

7. The method for assembling an interference fit hinge according to claim 1, characterized in that: The inner wall of the connecting hole is provided with a plurality of arc-shaped interference blocks, the shaft body is relatively rotatably arranged on the arc-shaped interference blocks, the contact surface between the arc-shaped interference blocks and the shaft body is an interference fit surface, and the oil storage groove is formed between adjacent arc-shaped interference blocks.

8. The method for assembling an interference fit hinge according to claim 7, characterized in that: An opening is provided on one side of the connecting hole, and the arc-shaped interference blocks are provided on both left and right ends of the opening close to the inner wall of the connecting hole.

9. The method for assembling an interference fit hinge according to claim 1, characterized in that: The butterfly-shaped spring piece is made of elastic material; the shaft body is a bolt structure, and the shaft body and the fixing piece are fixedly connected by a nut and a screw thread at the end of the bolt structure and a flat knurling structure; the connecting piece is a rivet structure.

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