Compound gear transmission device and method for nut large-torque tightening and torque monitoring

Abstract

The invention discloses a compound gear transmission device and method for nut large-torque tightening and torque monitoring, the device comprises a torque monitoring module, a torque amplification module, a reverse torque module and an input motor, the output end of the input motor is connected with the input end of the torque amplification module for transmitting power to the torque amplification module; the torque amplification module is provided with a reverse twisting module used for being connected with a reverse twisting hole site of an engine body to bear reverse twisting torque in the screwing process, the output end of the torque amplification module is connected with the input end of the torque monitoring module to be used for transmitting power to the torque monitoring module, and the output end of the torque monitoring module is used for being connected with a part to be screwed. According to the invention, the amplification of the torque from 4N. M to 10N. M to 2000N. M to 5000N. M is realized, so that the tightening torque of the nut and the real-time acquisition requirement of the torque in the tightening process are met, and meanwhile, the requirements of structural space constraint and light weight are met.

Description

Technical Field

[0001] This invention belongs to the field of assembly and connection technology, specifically to a composite gear transmission device and method for high-torque tightening and torque monitoring of nuts. Background Technology

[0002] Threaded connections are an important assembly connection method, widely used in electromechanical products. To ensure the reliability of the connection assembly and achieve the required service performance, process requirements are often specified for the tightening torque of the nuts. For critical threaded connections in major assemblies, very high tightening torques are often required, such as the preload nuts of heavy-duty truck axle differentials and the fastening nuts of multi-functional shafts in aircraft engines, which need to reach 2000~5000 N·m. To ensure that these critical structures achieve the specified assembly performance, it is necessary to accurately and reliably apply the tightening torque and monitor the torque during the tightening process, in order to adapt to the digital and intelligent requirements of the manufacturing process and achieve subsequent quality monitoring and problem traceability.

[0003] For manual nut tightening, torque wrenches and similar tools are typically used to control the tightening torque, generally with a maximum torque not exceeding tens of Newton-meters (Nm). With the aid of a torque multiplier, the torque can be further amplified, reaching hundreds of Nm. On automated assembly lines, automatic tightening guns are often used for assembling large batches of products, providing torque typically ranging from a few to tens of Nm. Therefore, there are many solutions for general nut tightening torques not exceeding hundreds of Nm. However, for torques between 2000 Nm and 5000 Nm, there are few good automatic tightening solutions. While manual operation can be achieved using dedicated torque multipliers integrated with torque wrenches, this cannot meet the monitoring and acquisition of torque information during the tightening process. To meet these specialized process requirements, compact and lightweight dedicated tightening fixtures have become an inevitable trend.

[0004] In the field of automatic tightening of high-torque nuts for aero-engines, some existing technical solutions have certain limitations. Some solutions present a high-torque electric tightening structure, which amplifies the torque by connecting a torque gun capable of outputting hundreds of torques in series with a single-stage parallel shaft reducer. This places very high technical requirements on the torque gun, which is difficult to meet with ordinary torque guns. Furthermore, the output stage of this mechanism is a single-stage parallel shaft gear transmission, resulting in a large overall structure. Moreover, the torque feedback in this structure is located at one end of the torque gun, and the presence of the reducer causes torque loss, making it impossible to accurately obtain the output torque. Other solutions use guide rods to adjust the position of the tightening head, employing multi-stage parallel shaft gear transmissions to amplify the torque and achieve a large tightening torque output. When the output torque reaches 2000 N·m to 5000 N·m, the overall structural size and weight of the parallel shaft gear transmission are very large, making it difficult to meet the requirements of structural compactness and lightweight design. Summary of the Invention

[0005] To address the problems existing in the prior art, this invention provides a composite gear transmission device and method for high-torque tightening and torque monitoring of nuts, so as to amplify the motor input torque from 4 N·m to 10 N·m to 2000 N·m to 5000 N·m, thereby meeting the requirements for real-time acquisition of the tightening torque and the torque during the tightening process of the nut, while also meeting the requirements for structural space constraints and lightweight design.

[0006] To achieve the above objectives, the present invention provides the following technical solution: a composite gear transmission device for high-torque tightening and torque monitoring of nuts, comprising a torque monitoring module, a torque amplification module, a reverse torque module, and an input motor. The output end of the input motor is connected to the input end of the torque amplification module to transmit power to the torque amplification module. The torque amplification module is provided with a reverse torque module to connect with the reverse torque hole of the engine block to bear the reverse torque during the tightening process. The output end of the torque amplification module is connected to the input end of the torque monitoring module to transmit power to the torque monitoring module. The output end of the torque monitoring module is used to connect to the component to be tightened.

[0007] Furthermore, the torque amplification module includes a low-speed internal gear and a three-stage gear transmission device. The three-stage gear transmission device consists of a hypoid gear transmission, a parallel shaft external gear transmission, and an NGW-type planetary gear transmission from the input end to the output end. The NGW-type planetary gear transmission meshes internally with the low-speed internal gear, which is fixed by a reverse torque module.

[0008] Furthermore, the quasi-hyperboloid gear transmission includes a quasi-hyperboloid pinion, a quasi-hyperboloid pinion shaft, and a quasi-hyperboloid gear. The output shaft of the input motor is connected to the quasi-hyperboloid pinion shaft via a coupling. The quasi-hyperboloid pinion on the quasi-hyperboloid pinion shaft and the quasi-hyperboloid gear form an interleaved shaft meshing. The parallel shaft external gear transmission includes a parallel shaft rotary shaft, a quasi-hypoid large gear fixed on the parallel shaft rotary shaft, the parallel shaft rotary shaft supported by a parallel shaft rotary shaft bearing, and the parallel shaft gear on the parallel shaft rotary shaft meshing with the input end of the NGW type planetary gear transmission; The NGW type planetary gear transmission includes a sun gear, planet gears, a low-speed internal gear, and a planet carrier. The sun gear is mounted on a double gear shaft, and the parallel shaft gear meshes with another gear on the double gear shaft. Planet gears are evenly distributed around the sun gear and are mounted on the planet carrier via planet gear shafts. The low-speed internal gear is fixed by a reverse torque module, and the planet gears mesh internally with the low-speed internal gear. The planetary gears mesh externally with the sun gear. Driven by the sun gear, the planetary gears rotate on their own axis and revolve around the center of the sun gear. The revolving motion of the planetary gears drives the planet carrier to rotate and output torque to the torque monitoring module.

[0009] Furthermore, the parallel shaft rotary shaft and the double gear shaft adopt a hollow design.

[0010] Furthermore, the double gear shaft and the sun gear transmit torque through an integral structure or a spline / key connection.

[0011] Furthermore, the planetary carrier is supported in the housing structure by planetary carrier bearings, and spring clips fix the position of the planetary carrier bearings.

[0012] Furthermore, the anti-torque module includes an output side plate and a lifting side plate. The low-speed internal gear of the NGW planetary gear transmission in the torque amplification module is fixed between the output side plate and the lifting side plate. A safety pin is provided on the output side plate for insertion into the anti-torque hole of the engine block, and a lifting hole is provided on the lifting side plate for lifting the compound gear transmission device to a designated position using lifting equipment.

[0013] Furthermore, the torque monitoring module includes a torque sensor output spline sleeve, a dynamic torque sensor, and a planetary carrier output sleeve. The output end of the torque amplification module is connected to the planetary carrier output sleeve. The planetary carrier output sleeve is connected to one side of the dynamic torque sensor via bolts. The other side of the dynamic torque sensor is connected to the tightening spindle via the torque sensor output spline sleeve. The tightening spindle is used to install the nut to be tightened. The dynamic torque sensor is used to monitor the tightening torque in real time.

[0014] This invention also provides a method for automatically tightening high-torque engine nuts, which employs the aforementioned composite gear transmission device for high-torque nut tightening and torque monitoring. The specific steps of the method are as follows: Fix the output end of the torque monitoring module to the engine component to be tightened, and connect the anti-torque module to the anti-torque hole of the engine block. The torque output from the input motor is applied to the component to be tightened through the torque amplification module and the torque monitoring module, thereby tightening the component.

[0015] Furthermore, during the automatic tightening process, the control system collects data from the torque monitoring module in real time and executes PID closed-loop control, including: If the target torque is not reached, the input motor is continuously driven and the torque growth rate is monitored; When the target value is approached, reduce the input motor speed; If the limits are exceeded or an abnormality occurs, the machine should be stopped immediately and an alarm should be triggered.

[0016] Compared with the prior art, the present invention has at least the following beneficial effects: This invention provides a composite gear transmission device for high-torque nut tightening and torque monitoring. It consists of four main modules: a torque monitoring module, a torque amplification module, a reverse torque module, and an input motor. These modules are closely connected and have clearly defined functions. The input motor transmits power to the torque amplification module, which amplifies the torque before transmitting it to the torque monitoring module, ultimately acting on the part to be tightened. The coordinated operation of these modules ensures the overall high efficiency of the device, providing a stable and reliable hardware foundation for nut tightening and torque monitoring. This device possesses a powerful torque amplification capability, increasing the input torque of a motor from 4 N·m to 10 N·m to 2000 N·m to 5000 N·m, precisely meeting the torque requirements for nut tightening. It can easily handle tightening operations with high-strength nuts or under special working conditions, ensuring proper tightening and effectively preventing loosening due to insufficient torque, thus providing a strong guarantee for the safe and stable operation of the equipment.

[0017] The torque monitoring module of this invention can collect torque data in real time during the tightening process, allowing operators to understand the tightening status of the nuts promptly. Real-time monitoring ensures that the tightening torque of each nut meets standard requirements, preventing uneven torque or excessive / insufficient torque from affecting equipment performance. This significantly improves the quality and reliability of nut tightening, laying a solid foundation for the long-term stable operation of the equipment.

[0018] The torque amplification module of this invention employs a three-stage gear transmission device, consisting of a hypoid gear transmission, a parallel shaft external gear transmission, and an NGW-type planetary gear transmission. This design allows for a smaller overall size of the large gears while ensuring sufficient strength in the smaller gears. It also achieves a 90° bend between the input and output shafts, reducing the overall axial dimension and maximizing the use of available space. Simultaneously, the multi-stage transmission reduces the number of transmission stages, decreases the number of components and manufacturing complexity, and contributes to a more compact and lightweight overall structure, meeting the requirements of modern machinery for miniaturization and weight reduction.

[0019] The parallel shaft rotary shaft and double gear shaft of this invention adopt a hollow design. This design ensures that the large gear retains sufficient strength even after having a large size and a hollow through-hole structure. This design facilitates the passage of auxiliary tooling through the hollow space, meets the arrangement requirements of auxiliary equipment such as pipelines and tools that may need to pass through during the tightening process, improves the versatility and practicality of the device, and enables the device to better adapt to different working environments and operational requirements.

[0020] The anti-torque module of this invention fixes the low-speed internal gear through an output side plate and a lifting side plate. The safety pin of the output side plate can be inserted into the anti-torque hole in the engine block to bear the anti-torque torque, and the lifting hole of the lifting side plate facilitates the lifting of the device. In the torque monitoring module, the dynamic torque sensor avoids the problem of signal / power line tangling, which facilitates lead wire arrangement and safe use. The planetary carrier is arranged with the inner ring space of the torque sensor through a spline structure, making full use of the hollow space, reducing the axial dimension, and ensuring stable operation and accurate data acquisition of the device during the tightening process.

[0021] The automatic tightening method for high-torque engine nuts provided by this invention only requires fixing the output end of the torque monitoring module to the engine component to be tightened and connecting the anti-torque module to the anti-torque hole in the engine block to begin the tightening operation. This connection method is stable and reliable, effectively withstanding various forces generated during the tightening process, ensuring that the device will not loosen or shift during tightening, providing a solid guarantee for the smooth progress of the tightening operation. During the automatic tightening process, the control system collects data from the torque monitoring module in real time and executes PID closed-loop control. Depending on different tightening stages, such as continuously driving the input motor and monitoring the torque growth rate when the target torque is not reached, reducing the input motor speed when approaching the target value, and immediately stopping and alarming when exceeding limits or abnormalities occur. This precise control method ensures that the nut is tightened to the accurate torque value, avoiding the problem of engine performance being affected by excessive or insufficient torque, and greatly improving the quality and reliability of tightening high-torque engine nuts.

[0022] This method employs the aforementioned composite gear transmission device. The device's multi-stage transmission, hollow design, and rational modular layout enable it to adapt to the high-torque nut tightening operations of engines of different specifications and models. Simultaneously, the automatic tightening method reduces manual operation errors and labor intensity, improves work efficiency, and can complete a large number of nut tightening operations in a short time, providing an efficient and reliable solution for engine production and maintenance. Attached Figure Description

[0023] Figure 1 This is an isometric structural schematic diagram of the present invention, wherein the dashed lines represent the anti-torsion modules.

[0024] Figure 2 This is an exploded view of the structure of the present invention.

[0025] Figure 3 This is an exploded schematic diagram of the three-stage gear transmission device of the present invention.

[0026] The components include: 1. Torque sensor output spline sleeve; 2. Dynamic torque sensor; 3. Planetary carrier output sleeve; 4. Output side plate; 5. Low-speed internal gear; 6. Three-stage gear transmission device; 7. Lifting side plate; 8. Housing; 9. Input motor; 10. Quasi-hypoid pinion shaft; 11. Planetary gear shaft; 12. Planetary carrier; 13. Planetary carrier bearing; 14. Spring circlip; 15. Planetary gear; 16. Double gear shaft; 17. Double gear shaft bearing; 18. Parallel shaft rotary shaft; 19. Parallel shaft rotary shaft bearing; 20. Quasi-hypoid large gear. Detailed Implementation

[0027] The following are specific embodiments of the present invention. It should be noted that the present invention is not limited to the following specific embodiments. All equivalent modifications made based on the technical solutions of this application fall within the protection scope of the present invention.

[0028] like Figures 1-3 As shown, the present invention provides a composite gear transmission device for high torque tightening and torque monitoring of nuts, including a torque amplification module, a torque monitoring module, an anti-torque module, and a connecting flange fixture.

[0029] The torque amplification module includes a low-speed internal gear 5 and a three-stage gear transmission device 6, used to achieve three-stage torque amplification and direction change. This structure, from input to output, consists of a hypoid gear transmission, a parallel shaft external gear transmission, and an NGW-type planetary gear transmission. Specifically, the output shaft of the input motor 9 is connected to the hypoid pinion shaft 10 in the gear transmission device via a coupling. A support bearing is installed on the hypoid pinion shaft 10, and power is transmitted to the hypoid large gear 20 through hypoid gear meshing, achieving initial torque amplification and direction change. The hypoid large gear 20 meshes with the double gear shaft 16 via a parallel shaft rotary shaft 18, achieving secondary torque amplification. The NGW-type planetary gear transmission consists of a sun gear, planet gears 15, a low-speed internal gear 5, a planet carrier 12, and a planet gear shaft 11 on the double gear shaft 16, achieving three-stage torque amplification. Preferably, in the NGW-type planetary gear transmission, the sun gear is driven by a double gear shaft 16, and planet gears 15 are distributed around the sun gear and mounted on the planet carrier 12 via planet gear shaft 11. A low-speed internal gear 5 is sleeved around the planet carrier 12 and is connected to the output side plate 4 and the lifting side plate 7 by bolts, fixed in the housing 8 structure, serving as a fixed gear ring. The planet carrier 12 supports the planet gears 15 and transmits the output torque. The double gear shaft 16 (the output component of the parallel shaft gear transmission) transmits the torque to the sun gear, driving it to rotate. The planet gears 15 mesh externally with the sun gear and internally with the low-speed internal gear 5. Due to the constraint of the anti-torque module, the low-speed internal gear 5 remains stationary, while the planet gears 15 rotate under the drive of the sun gear and simultaneously revolve around the center of the sun gear. The revolve motion of the planet gears 15 drives the planet carrier 12 to rotate. The planet carrier 12 is connected to the planet carrier output sleeve 3 via an external spline, transmitting the amplified torque to the torque monitoring module.

[0030] Preferably, the double gear shaft 16 transmits torque to the sun gear via an integrated structure or a spline / key connection, ensuring lossless power input. The planetary gears 15 are mounted in the holes of the planetary carrier 12 via the planetary gear shaft 11, allowing free rotation. The planetary carrier 12 is supported on the housing 8 structure by the planetary carrier bearing 13, and the bearing position is fixed by a spring retainer 14 to prevent axial movement. The low-speed internal gear 5 is bolted to the output side plate 4 and the lifting side plate 7, and transmits counter-torque to the engine block via a safety pin, ensuring that the low-speed internal gear 5 remains stationary during power transmission. The output end of the planetary carrier 12 is connected to the planetary carrier output sleeve 3 via an external spline, forming a rigid torque transmission path. The planetary carrier output sleeve 3 is bolted to the dynamic torque sensor 2, enabling torque transmission to the monitoring module.

[0031] The torque monitoring module includes a torque sensor output spline sleeve 1, a dynamic torque sensor 2, and a planetary carrier output sleeve 3. The dynamic torque sensor 2 is used to monitor the tightening torque in real time. The power of the planetary carrier 12 is transmitted to the internal spline of the planetary carrier output sleeve 3 via the external spline. The planetary carrier output sleeve 3 is connected to one side of the dynamic torque sensor 2 via bolts, and the other side of the dynamic torque sensor 2 transmits the torque to the tightening spindle through the torque sensor output spline sleeve 1. The dynamic torque sensor 2 is used to monitor the tightening torque in real time.

[0032] The anti-torque module includes an output side plate 4 and a lifting side plate 7. The low-speed internal gear 5 is fixed to the output side plate 4 and the lifting side plate 7 by bolts. The safety pin of the output side plate 4 is inserted into the anti-torque hole of the engine block to bear the anti-torque torque during the tightening process. The planetary carrier 12 forms a support structure with the output side plate 4 through the planetary carrier bearing 13 to ensure the rotation positioning accuracy.

[0033] Preferably, the quasi-hyperboloid large gear 20 and the parallel shaft rotary shaft 18 transmit torque via a key; Preferably, the planetary carrier 12 and the planetary carrier output sleeve 3 are connected by an external spline and an internal spline, and the torque sensor output spline sleeve 1 is connected to the tightening spindle by a spline.

[0034] Preferably, the planetary carrier output sleeve 3 and the torque sensor output spline sleeve 1 are located in the inner cavity of the dynamic torque sensor 2, thus shortening the overall axial dimension.

[0035] Preferably, the planetary carrier output sleeve 3 and the dynamic torque sensor 2, and the dynamic torque sensor 2 and the torque sensor output spline sleeve 1 are all fixed by bolts.

[0036] Preferably, the parallel shaft rotary shaft 18 and the double gear shaft 16 adopt a hollow design, which can reduce weight and optimize the dynamic performance of the transmission system.

[0037] This embodiment also provides an assembly process for a composite gear transmission device for high-torque nut tightening and torque monitoring, including the following steps: 1. Pre-assembly of basic components 1.1 Anti-torsion module assembly The low-speed internal gear is fixed to the output side plate: The low-speed internal gear 5 is bolted to the output side plate 4, and a safety pin is inserted for positioning and to withstand the reverse torque, ensuring that the coaxiality error between the two is ≤0.05mm.

[0038] Pre-installation of hoisted side panels: The hoisting side plate 7 and the low-speed internal gear 5 are initially positioned using safety pins, and the bolts are pre-tightened to 50% of the design torque (leaving room for adjustment).

[0039] 1.2NGW Planetary Gear Module Integration Planetary carrier assembly assembly: Install the planetary gears 15 and planetary gear shafts 11 into the corresponding holes of the planetary carrier 12, install the planetary carrier bearings 13 and fix them axially using spring clips 14 to ensure that the planetary gears rotate flexibly without jamming.

[0040] Final fixing of the hoisted side panels: After the hoisting side plate 7 and the low-speed internal gear 5 are fully aligned using the safety pin, the bolts are fully tightened to the design torque value.

[0041] 2. Intermediate stage gear transmission assembly 2.1 Parallel Shaft Gear Assembly Installation Bearing pre-installation: Bearings are installed on both sides of the parallel shaft rotary shaft 18 (the right bearing is not positioned for the time being), and the outer ring of the left bearing is pressed into the bearing seat of the housing 8.

[0042] Gear-shaft integration: Assemble the parallel shaft rotary shaft 18 with the double gear shaft 16 to ensure that the gear meshing clearance meets the design value (0.1~0.2mm).

[0043] Hypoid gear centering: Install the quasi-hyperboloid large gear 20 and connect it to the parallel shaft rotary shaft 18 via a key. After axial positioning, install the right-side bearing and the housing cover.

[0044] 2.3 Box Closure Align the eight separate parts of the housing with the locating pins, and tighten the bolts in a diagonal sequence to the designed torque.

[0045] 3. Input stage transmission and drive integration 3.1 Installation of the quasi-hyperboloid pinion The hypoid pinion shaft 10 and the bevel gear rotary shaft bearing are installed in the hollow space below the housing, and then fixed after adjusting the bearing preload.

[0046] 3.2 Input motor connection The output shaft of the input motor 9 is connected to the quasi-hyperboloid pinion shaft 10 via a coupling. The motor base is fixed to the housing with bolts, and the coaxiality error is ≤0.03mm.

[0047] 4. Torque monitoring module integration 4.1 Sensor Component Connection The planetary carrier output sleeve 3, dynamic torque sensor 2, and torque sensor output spline sleeve 1 are connected in sequence by bolts to ensure that the spline mating section is coaxial and slides smoothly.

[0048] 4.2 Verification of the end-effector torque transmission path Manually rotate the input motor to check that there is no interference in the torque transmission path from the planetary carrier output sleeve to the sensor and then to the spline sleeve. Ensure that the sensor signal wire is led out and protected.

[0049] 5. Final Fixing and Debugging 5.1 Overall fastening Check that all bolts (including anti-torsion modules, planetary carrier bearings, and housing connections) are tightened to the designed torque and that the safety pins are not sheared.

[0050] 5.2 No-load trial operation The input motor is started briefly, and the sensor output signal under no-load is monitored to ensure stability. The planetary gear system operates without abnormal noise, and the temperature rise is ≤15℃ / 10min.

[0051] The above steps enable high-precision assembly of the composite gear transmission device, meeting the requirements for high torque transmission and dynamic monitoring.

[0052] This embodiment also provides a method for using a composite gear transmission device for high-torque nut tightening and torque monitoring, including the following steps: 1. Preparations before operation 1.1 Equipment hoisting and positioning Using hoisting equipment connected to the hoisting holes on the hoisting side plate 7, the entire transmission system is hoisted to the designated position where the engine nut is to be tightened, ensuring a positioning accuracy error of ≤±1mm. Avoid collisions during hoisting to prevent deformation of the gearbox or sensor components.

[0053] 1.2 Reverse Twist Tooling Connection Insert the dedicated anti-torque fixture into the anti-torque shaft hole of the output side plate 4. Achieve precise alignment through shaft-hole fit (tolerance H7 / g6), insert the safety pin to secure it, and verify the load-bearing capacity. The anti-torque fixture must be rigidly connected to the engine block to ensure effective transmission of anti-torque torque.

[0054] 2. Tool Installation and Integration 2.1 Nut tightening tool connection Fit the special tool for tightening large nuts with the surface of the nut to be tightened, ensuring that the threads are aligned and not misaligned.

[0055] Insert the outer spline end of the dedicated torque bar into the inner spline hole of the torque sensor output spline sleeve 1 of the transmission system, and rotate to verify the smoothness of the spline fit; the axial clearance should be ≤0.1mm. Lubricant should be applied to the spline connection to prevent jamming or wear.

[0056] 2.2 Auxiliary tooling installation The auxiliary guide fixtures, data acquisition cables, etc. are passed through the through holes in the transmission system housing to fix the cables and prevent interference with moving parts.

[0057] 3. Tightening operation execution 3.1 System Startup and Parameter Settings Start the control system and input parameters such as target torque value, tightening speed, and torque tolerance range.

[0058] Enable the real-time monitoring function of dynamic torque sensor 2 and calibrate the sensor zero-point offset.

[0059] 3.2 Automated Tightening Control Start the input motor 9, which amplifies the torque step by step through a three-stage gear transmission (quasi-hyperboloid → parallel shaft → NGW planetary gear) to drive the nut to tighten.

[0060] The control system acquires torque sensor data in real time and executes PID closed-loop control. Target torque not reached: Continuously drive the motor and monitor the torque growth rate.

[0061] Approaching the target value: Reduce the rotation speed to achieve precise tightening (soft stop function).

[0062] Exceeding limits or abnormalities: Immediately stop the machine and issue an alarm (e.g., sudden drop in torque, speed fluctuation exceeding 5%).

[0063] 4. Data Management and Strategy Optimization Once tightening is complete, the control system collects and records torque curve information throughout the process and uploads it to the upper-level management system, forming a traceable quality data chain. Simultaneously, based on historical data analysis, it optimizes subsequent tightening strategies, achieving parameter self-adaptation and strategy updates, further enhancing the system's intelligence and stability. The high-torque tightening transmission system is separated from the nut tightening, the dedicated torque bar for nut tightening, and the dedicated anti-torque fixture to complete the operation.

[0064] By standardizing operating procedures, the composite gear transmission device can achieve high precision, high reliability, and intelligent operation in scenarios involving high torque tightening of nuts.

[0065] Example 1 This invention provides a composite gear transmission device for high-torque nut tightening and torque monitoring, including a torque monitoring module, a torque amplification module, an anti-torque module, a connecting flange fixture, and a housing structure; the overall structure has an axial dimension ≤350mm, a maximum radial outer diameter ≤280mm, a total weight ≤85kg, and is applicable to a tightening torque range of 500-8000N·m, covering large nut tightening scenarios in automobiles, construction machinery, etc.

[0066] The torque monitoring module includes a torque sensor output spline sleeve 1, a dynamic torque sensor 2, and a planetary carrier output sleeve 3. The torque amplification module transmits power to the planetary carrier output sleeve 3, and then sequentially transmits the power to the dynamic torque sensor 2 and the torque sensor output spline sleeve 1 via bolt connections. Finally, the torque output is connected to the tightening spindle via a spline connection, and the tightening spindle is used to perform the tightening action. In this process, to ensure the monitoring of the actual tightening torque, the dynamic torque sensor 2 is installed at the final stage of the power output. Compared to directly monitoring the output torque of the input motor 9 and calculating the tightening torque based on the transmission ratio, this method can avoid torque loss caused during power transmission.

[0067] Among them, the dynamic torque sensor 2 has a range of 0-10,000 N·m, an accuracy of ±0.5%FS, and an output signal frequency of 1kHz; the spline connection adopts an involute spline (module 2.5, number of teeth 24), with a transmission efficiency of ≥99.2%; the sensor installation position shortens the axial dimension by about 15%, and the overall module weight is reduced by 12%.

[0068] The torque amplification module includes a low-speed internal gear 5 and a three-stage gear transmission device 6, wherein the three-stage gear transmission device 6 further includes a quasi-hyperboloid pinion shaft 10, a planetary gear shaft 11, a planetary carrier 12, a planetary carrier bearing 13, a spring circlip 14, a planetary gear 15, a double gear shaft 16, a double gear shaft bearing 17, a parallel shaft rotary shaft 18, a parallel shaft rotary shaft bearing 19, and a quasi-hyperboloid large gear 20. The input motor 9 is connected to the hypoid pinion shaft 10 via a coupling. Through the hypoid gear transmission, the power is transmitted to the hypoid gear 20, achieving initial torque amplification and a change in transmission direction. The hypoid gear 20 is fixed to the parallel shaft rotary shaft 18 via a key connection for torque transmission and is supported by the parallel shaft rotary shaft bearing 19. The parallel shaft rotary shaft 18 transmits power to the double gear shaft 16 through the parallel shaft gear transmission, achieving secondary torque amplification, and is supported by the double gear shaft bearing 17. The parallel shaft rotary shaft 18 adopts a hollow structure to achieve lightweight design. The sun gear, planet carrier 12, low-speed internal gear 5, planet gear 15 and planet gear shaft 11 on the double gear shaft 16 together form an NGW type planetary gear, realizing three-stage amplification of tightening torque. The planet carrier bearing 13 supports the planet carrier 12 and the spring clasp 14 to ensure that the planet carrier bearing 13 is firmly fixed in its installation position, preventing the bearing from shifting or falling off and ensuring the rotational accuracy of the planet carrier 12.

[0069] The torque amplification module transmits the power of the planetary carrier 12 to the planetary carrier output sleeve 3 through a toothed spline.

[0070] Among them, the hypoid gear transmission has a transmission ratio of 3.2:1, uses 20CrMnTi material, and achieves a hardness of HRC58-62 after surface carburizing and quenching, with a transmission efficiency of 93.5%; the parallel shaft gear transmission has a transmission ratio of 4.1:1, a gear precision grade of ISO5, a hollow shaft outer diameter of 80mm and an inner diameter of 40mm, and successfully reduced weight by 17.5% through lightweight design; the NGW planetary gear has a transmission ratio of 5.2:1, 14 teeth on the sun gear, 22 teeth on the planet gears, and 58 teeth on the internal gear ring, with a total transmission ratio of 3.2×4.1×5.2≈68.224:1 and a transmission efficiency of 91.5%.

[0071] The total torque amplification factor is approximately 68 times. When the rated torque of the input motor is 100 N·m, the theoretical output torque can reach 6,800 N·m. Considering various complex factors such as friction and heat dissipation in the actual working environment, after repeated testing and optimization, the maximum output torque was finally determined to be 5,000 N·m to ensure the reliability and safety of the device during long-term stable operation.

[0072] The anti-torque module includes an output side plate 4 and a mounting side plate 7. The low-speed internal gear 5 of the torque amplification module is fixed to the output side plate 4 and the mounting side plate 7 respectively by bolts. The anti-torque generated by the torque amplification module during tightening is transmitted to the engine block by the safety pin on the output side plate 4 to ensure the normal operation of the composite gear transmission device.

[0073] Among them, the safety pin is made of 40Cr material, with a shear strength ≥600MPa, a diameter of 8mm, and a single pin bearing capacity ≥10kN; The alignment tolerance between the output side plate and the engine block is ≤0.1mm, and the reverse torque transmission efficiency is ≥95%.

[0074] When using the composite gear transmission device for high-torque nut tightening and torque monitoring according to the present invention, the target torque is set to a typical value of 500-800 N·m for automotive wheel hub nuts, and up to 5,000 N·m for heavy-duty machinery nuts; the tightening speed is controllable from 5-20 rpm, the data acquisition frequency is 1 kHz, and the torque curve resolution is 0.1 N·m; the single tightening cycle is ≤30 seconds (including automatic tool retraction time), and the system thermal stability is ≤±0.3%FS / h; the specific steps are as follows: (1) By connecting the hoisting equipment and corresponding ropes to the hoisting holes of the hoisting side plate 7, the compound gear transmission device is placed at the designated position of the engine nut to be tightened; (2) Align the safety pin of the output side plate 4 with the anti-torsion hole reserved in the engine body; (3) Install the tightening spindle with the nut to be tightened through the through hole of the compound gear transmission device, and connect the inner spline of the spline 1 output by the torque sensor with the outer spline of the tightening spindle. (4) Pass the remaining auxiliary tools through the through hole of the high-torque tightening transmission system; (5) Controlling the tightening action of the high-torque tightening transmission system; (6) Tightening complete, operation finished.

[0075] The specific operation of the device of the present invention and the conventional solution are compared in the following table:

[0076] As can be seen from the data in the table, by directly monitoring with an end dynamic torque sensor, efficiently amplifying with a three-stage gear transmission, and rigidly fixing with a reverse torque module, this invention is significantly superior to traditional solutions in terms of accuracy, efficiency, and intelligence, and is especially suitable for high-precision, high-torque automated assembly scenarios.

[0077] In summary, this invention employs a three-stage composite gear transmission device, achieving the goal of high torque transmission while minimizing the number of transmission stages, effectively reducing the number of system components and manufacturing complexity. The input stage utilizes a quasi-hypoid gear transmission. On one hand, while ensuring sufficient strength of the smaller gear, the larger gear's structural dimensions are smaller than ordinary bevel gears, greatly contributing to the overall compactness and lightweight design. On the other hand, it achieves a 90° angle between the input and output shafts, which is significant for reducing the overall axial dimension of the multi-stage gear composite transmission system, allowing for full and efficient utilization of the working space. The intermediate stage uses a parallel shaft gear transmission, ensuring the larger gear has a substantial size and retains sufficient strength even after hollow through-hole construction, fully meeting the practical requirements for the hollow passage of auxiliary tooling. The output stage uses an NGW-type planetary gear transmission, evenly distributing torque through multiple planetary gears, further reducing the overall structural size. Furthermore, the low-speed internal gear can be integrated with the housing, greatly simplifying the manufacturing and assembly process. Furthermore, in terms of torque monitoring, the torque sensor is located at the output end of the composite transmission gear train, enabling direct and accurate monitoring of the torque signal. This effectively eliminates the torque loss problem caused by the torque sensor being located on the motor input side and passing through multiple gear transmission stages. Simultaneously, the use of a dynamic torque sensor avoids the entanglement issues caused by the signal / power lines of ordinary static torque sensors rotating with the output shaft, greatly simplifying the wiring layout of the entire system structure and ensuring operational safety. The output stage planetary carrier is cleverly arranged within the inner ring space of the torque sensor via a spline structure. The output normal of the torque sensor is also located within this inner ring space, fully utilizing the hollow space of the inner ring of the torque sensor, further reducing the axial dimension and providing strong support for the miniaturization of the overall structure.

Claims

1. A combined gear drive for nut high torque tightening and torque monitoring, characterized in that, The torque monitoring module, the torque amplification module, the counter-torque module, the input motor (9), the output end of the input motor (9) is connected with the input end of the torque amplification module for transmitting power to the torque amplification module, the counter-torque module is arranged on the torque amplification module for being connected with the counter-torque hole of the engine body to bear the counter-torque in the tightening process, the output end of the torque amplification module is connected with the input end of the torque monitoring module for transmitting power to the torque monitoring module, and the output end of the torque monitoring module is used for being connected with the component to be tightened.

2. A combined gear drive for nut high torque tightening and torque monitoring according to claim 1, characterized in that The torque amplification module comprises a low-speed internal gear (5) and a three-stage gear transmission device (6), the three-stage gear transmission device (6) is quasi-hyperboloidal gear transmission, parallel shaft external gear transmission and NGW type planetary gear transmission from the input end to the output end, the NGW type planetary gear transmission is internally meshed with the low-speed internal gear (5), and the low-speed internal gear (5) is fixed through the counter-torque module.

3. A combined gear drive for nut high torque tightening and torque monitoring according to claim 2, characterized in that The quasi-hyperboloidal gear transmission comprises a quasi-hyperboloidal pinion, a quasi-hyperboloidal pinion shaft (10) and a quasi-hyperboloidal gear (20), the output shaft of the input motor (9) is connected with the quasi-hyperboloidal pinion shaft (10) through a shaft coupling, the quasi-hyperboloidal pinion on the quasi-hyperboloidal pinion shaft is in staggered shaft meshing with the quasi-hyperboloidal gear (20); The parallel shaft external gear transmission comprises a parallel shaft rotary shaft (18), the quasi-hyperboloidal gear (20) is fixed on the parallel shaft rotary shaft (18), the parallel shaft rotary shaft (18) is supported through a parallel shaft rotary shaft bearing (19), and the parallel shaft gear on the parallel shaft rotary shaft (18) is in meshing with the input end of the NGW type planetary gear transmission; The NGW type planetary gear transmission comprises a sun gear, a planet gear (15), a low-speed internal gear (5) and a planet carrier (12), the sun gear is arranged on a double gear shaft (16), the parallel shaft gear is in meshing with another gear of the double gear shaft (16), the planet gears (15) are uniformly distributed around the sun gear, the planet gears (15) are installed on the planet carrier (12) through planet gear shafts (11), the low-speed internal gear (5) is fixed through the counter-torque module, and the planet gears (15) are in meshing with the low-speed internal gear (5) internally; The planet gears (15) are in meshing with the sun gear externally, the planet gears (15) rotate around the sun gear under the drive of the sun gear, and the revolution movement of the planet gears (15) drives the planet carrier (12) to rotate and output torque to the torque monitoring module.

4. A combined gear drive for nut high torque tightening and torque monitoring according to claim 3, characterized in that The parallel shaft rotary shaft (18) and the double gear shaft (16) adopt a hollow design.

5. A combined gear drive for high torque nut tightening and torque monitoring according to claim 3, characterized in that The double gear shaft (16) and the sun gear transmit torque through an integrated structure or a spline / key connection.

6. A combined gear drive for high torque nut tightening and torque monitoring according to claim 3, characterized in that The planet carrier (12) is supported in the box body (8) through a planet carrier bearing (13), and a spring collar (14) fixes the position of the planet carrier bearing (13).

7. A combined gear drive for high torque nut tightening and torque monitoring according to claim 1, characterized in that The anti-torque module comprises an output side plate (4) and a hoisting side plate (7), and the low-speed inner gear (5) of the NGW type planetary gear transmission in the torque amplification module is fixed between the output side plate (4) and the hoisting side plate (7) and in the box (8); the safety pin is arranged on the output side plate (4) and is used for being inserted into the anti-torque hole of the engine body, and the hoisting hole is arranged on the hoisting side plate (7) and is used for hoisting the composite gear transmission device to the specified position by using the hoisting equipment.

8. A combined gear drive for nut high torque tightening and torque monitoring according to claim 1, characterized in that, The torque monitoring module comprises a torque sensor output spline sleeve (1), a dynamic torque sensor (2) and a planet carrier output sleeve (3), the output end of the torque amplification module is connected with the planet carrier output sleeve (3), the planet carrier output sleeve (3) is connected with one side of the dynamic torque sensor (2) through a bolt, the other side of the dynamic torque sensor (2) is connected with the tightening spindle through the torque sensor output spline sleeve (1), and the tightening spindle is used for being installed with the nut to be tightened; the dynamic torque sensor (2) is used for monitoring the tightening torque in real time.

9. An engine large torque nut automatic tightening method, characterized by, The method is carried out by using the composite gear transmission device for nut large-torque tightening and torque monitoring in any one of claims 1-8, and the specific steps are as follows: The output end of the torque monitoring module is fixed with the engine component to be tightened, and the anti-torque module is connected with the anti-torque hole of the engine body; The torque output by the input motor (9) acts on the component to be tightened through the torque amplification module and the torque monitoring module, so as to realize the tightening of the component to be tightened.

10. The method of claim 9, wherein the method further comprises: During the automatic tightening process, the control system collects the data of the torque monitoring module in real time, and executes PID closed-loop control, including: When the target torque is not reached, the input motor (9) is continuously driven and the torque growth rate is monitored; When the target value is approached, the input motor (9) speed is reduced; When the limit or abnormality is exceeded, the machine is immediately stopped and an alarm is given.

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