A flexible split torque fastening device suitable for narrow areas

Abstract

The present invention discloses a flexible, split torque tightening device suitable for use in confined spaces. The device comprises a tightening gun, a flexible transmission mechanism, and a torque output terminal. The tightening gun contains a controller that processes and calculates torque before activating an internal motor. The torque is then transmitted to the torque output terminal via the flexible transmission mechanism, thereby controlling the tightening of the bolt. The torque output terminal also provides feedback to the controller regarding the current torque level. The device is detachable and highly precise, enabling flexible adaptation to various confined spaces while also precisely controlling the tightening torque.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical equipment, and in particular to a flexible split-type torque fastening device suitable for narrow locations. Background Art

[0002] In industrial assembly, the precision and reliability of bolt tightening processes directly impact equipment sealing, structural stability, and service life. Traditional manual or pneumatic tightening tools suffer from large torque output deviations, insufficient spatial adaptability, and a lack of real-time feedback. This is particularly true when operating in confined spaces (such as flange gaps, engine compartments, or within precision electronic equipment). Conventional tools often experience torque loss or bolt slippage due to structural interference. The one-way drive of traditional ratchet wrenches relies on frequent manual reversing, resulting in low efficiency. Furthermore, cumbersome socket replacement and insufficient anti-slip performance further restrict assembly quality and efficiency. Summary of the Invention

[0003] In view of the shortcomings of traditional bolt tightening tools such as large torque deviation and poor spatial adaptability, the present invention provides a flexible split torque tightening device suitable for narrow areas.

[0004] The present invention comprises:

[0005] A tightening gun, which includes a controller and a power source, wherein the controller is used to receive a target torque value and control the power source to output corresponding power;

[0006] a flexible transmission mechanism connecting the tightening gun and the torque output terminal for transmitting the power of the tightening gun to the torque output terminal, the flexible transmission mechanism including a flexible force transmission component capable of transmitting torque in a narrow or tortuous space and allowing bending of the torque transmission path;

[0007] A torque output terminal is connected to the flexible transmission mechanism and is used to convert the power transmitted by the flexible transmission mechanism into torque and apply it to the fastener. The torque output terminal includes a torque feedback device, which is used to measure the actual applied torque and feed back the signal to the controller. The controller adjusts the output of the power source according to the feedback signal to achieve precise control of the torque.

[0008] Beneficial effects of the present invention: The present invention achieves technological upgrades through an innovatively developed modular high-precision torque output system. The device innovatively integrates a ratchet mechanism, a dynamic servo closed-loop control component, and a wire rope flexible cable transmission mechanism. Through a rigid-flexible coupling transmission mechanism, it achieves precise output of directional torque in a narrow space, while supporting rapid replacement of sleeves, significantly improving assembly efficiency and reliability, and is suitable for precision industrial scenarios such as large transformers and aviation. BRIEF DESCRIPTION OF THE DRAWINGS

[0009] Figure 1 To tighten the gun end structure diagram;

[0010] Figure 2 This is the torque output terminal structure diagram;

[0011] Figure 3 It is the structural diagram of the flexible transmission mechanism;

[0012] Figure 4 is the torque transfer curve;

[0013] Figure 5 The overall structure diagram of the device;

[0014] Figure 6 This is the working flow diagram of the device system;

[0015] Figure 7 This is the flow chart of the torque control algorithm. DETAILED DESCRIPTION

[0016] To make the objects, technical solutions, and advantages of the present invention more apparent, the present invention will be described in further detail with reference to the accompanying drawings. This description introduces specific embodiments consistent with the principles of the present invention by way of example and not limitation. The descriptions of these embodiments are sufficiently detailed to enable those skilled in the art to practice the present invention. Other embodiments may be used and the structures of the various elements may be changed and / or replaced without departing from the scope and spirit of the present invention. Therefore, the following detailed description should not be understood in a restrictive sense.

[0017] This application provides a flexible split torque tightening device suitable for narrow areas. The device consists of a tightening gun, a flexible transmission mechanism, and a torque output terminal. The tightening gun contains a controller that starts the internal motor after processing and calculating the torque. The torque is transmitted to the torque output terminal through the flexible transmission mechanism, thereby controlling the tightness of the bolt. At the same time, the torque output terminal can feedback the current torque size to the controller. Unlike traditional torque wrenches, this device is detachable and highly precise. It can not only flexibly adapt to various narrow spaces, but also accurately control the tightening torque.

[0018] The tightening gun is the core control and power unit of the device. It integrates a controller and a reduction motor, and achieves high-precision torque output through an intelligent closed-loop system. The controller, as the "brain", contains a microprocessor and a communication module. It can receive the target torque value set by the user and run the real-time control algorithm. At the same time, it establishes a data exchange channel with the sensor at the torque output terminal. The controller also includes a limit protection function. When the transmission mechanism reaches the preset stroke limit, it immediately triggers a signal and the controller stops the motor to avoid overload damage to the transmission mechanism or mechanism jamming. The reduction motor unit consists of a servo motor and a gear reducer. It converts the high-speed and low-torque of the motor into a low-speed and high-torque output, which is suitable for the power characteristics required for bolt tightening.

[0019] In a preferred embodiment, if Figure 1 As shown, the tightening gun end comprises a tightening gun 11, a first sleeve 12, a first drum 13, a limiting mechanism 14, a top plate 15, and a bottom plate 16, forming a functional assembly. Specifically, the output end of the tightening gun 11 utilizes a quadrangular prism shaft structure, forming a zero-clearance transition fit with the quadrangular inner cavity of the first sleeve 12. The first sleeve 12 also achieves a zero-clearance fit with the quadrangular prism boss of the drive shaft of the first drum 13. The first drum 13 is supported by a rolling bearing assembly within a rigid frame formed by the top plate 15 and bottom plate 16. This frame is vertically positioned by a copper column and nut assembly. The limiting mechanism 14 is fastened to the top plate via a bolt-nut pair, constraining the torsional torque transmission path.

[0020] The device's power system integrates a servo controller and a reduction motor assembly with the tightening gun 11, establishing a mechanical transmission chain through the first sleeve 12 and the first drum 13. The first drum 13 houses two counter-rotating steel wire ropes 21. When the actuator is activated, the reduction motor rotates the first sleeve 12, which in turn drives the first drum 13 in a bidirectional winding operation. A specially designed mechanical limiter 14 effectively suppresses angular displacement of the tightening gun 11 caused by the reaction torque generated by the actuation of the first drum 13 through physical interference.

[0021] The torque output terminal is the core execution unit that accurately applies the torque transmitted by the flexible transmission mechanism to the bolt and realizes torque feedback. Its structure consists of a ratchet mechanism, a second sleeve, and a torque sensor.

[0022] The ratchet body is made of steel and has a bidirectional pawl integrated inside. When the flexible transmission mechanism drives the ratchet input shaft to rotate through the second reel, the engagement mechanism between the pawl and the tooth groove (such as clockwise locking / counterclockwise idling) ensures continuous unidirectional torque output during the bolt tightening process to prevent back-off and loosening.

[0023] The second sleeve is connected to the ratchet output shaft via a hexagonal magnetic interface, supporting the rapid replacement of bolt heads of various specifications.

[0024] The torque sensor is based on a strain gauge or piezoelectric principle and is located on the limit device. When the second sleeve drives the bolt to rotate, the generated reaction force acts on the limit device, thereby measuring the actual torque in real time and feeding the signal back to the tightening gun controller, forming an "output-monitoring-calibration" closed loop.

[0025] In a preferred embodiment, if Figure 2 As shown, the torque output terminal is composed of a second drum 31, a driving gear 32, a driven gear 33, a second sleeve 34, a pawl 35, a limiter 36, an upper bearing plate 37 and a lower base plate 38 as core components. The second drum 31 has two symmetrically distributed pre-tightened steel wire ropes 21 integrated inside. Its rotation axis is supported by a double-plate structure through a bearing group, and the upper bearing plate and the lower base plate are rigidly fixed by a bolt group. The driving gear 32 is connected to the second drum 31 with a zero-clearance fit and forms an orthogonal axis gear pair with the driven gear 33. The output end of the driven gear 33 is a quadrangular prism drive shaft, which forms a zero-clearance fit with the inner cavity of the second sleeve 34. A threaded pair engagement surface may also be provided at the end of the second sleeve 34, and its rotational freedom is constrained by the ratchet mechanism: the pawl 35 is a symmetrical double-pawl structure. When the pawl 35 is not engaged with the tooth groove of the driving gear 32, the torque of the second reel 31 is transmitted to the second sleeve 34 through the gear pair, driving the threaded pair to rotate; when the pawl 35 system enters a unilateral engagement state, the second sleeve 34 is constrained by the ratchet mechanism to only maintain a unidirectional degree of freedom; and under bilateral engagement, the second sleeve 34 will enter a bidirectional self-locking state.

[0026] The limiter 36 is bolted to the underside of the lower base plate 38 and utilizes a hardened alloy steel stopper structure to mechanically suppress the reaction torque during the actuation of the threaded pair. The system's power transmission path involves the wire rope 21 driving the second drum 31, which is then transmitted via the driving gear 32 and driven gear 33 to the second sleeve 34, ultimately acting on the threaded pair, forming a closed-loop torque output system.

[0027] The flexible transmission mechanism is responsible for achieving flexible transmission and direction conversion of torque in a narrow or tortuous space. Its structure consists of a bidirectionally wound wire rope assembly and a drum system.

[0028] The main body utilizes two high-strength steel cables wrapped in a wear-resistant rubber sheath to prevent debris from metal friction and reduce rigid resistance during bending. The two cables are wound in opposite directions (clockwise and counterclockwise) around two sets of reels at the tightening gun and torque output terminal, respectively, creating a symmetrical tension structure that ensures stable torque transmission during forward and reverse rotation. When the tightening gun's reduction motor drives the reel at the gun end to rotate, the reel generates traction through retraction and expansion, driving the terminal reel to rotate synchronously, thereby transmitting torque losslessly to the terminal actuator.

[0029] In a preferred embodiment, if Figure 3As shown, the flexible transmission mechanism mainly includes two steel ropes 21, which are wrapped in protective sheaths, as well as a first drum 13 and a second drum 31. The first drum 13 and the second drum 31 are located at the tightening gun and the torque output terminal, respectively. One end of the two steel ropes is wound in reverse on the drum, and the other end is also wound in reverse on the other drum. When one of the drums starts to rotate, due to the opposite winding directions of the steel ropes, the drum can drive one of the steel ropes to contract and the other to release. Correspondingly, on the other drum, one of the steel ropes is released and the other is contracted. The flexible transmission mechanism couples the input end and the output end. Figure 4 The torque transfer curve shows the relationship between the input torque (horizontal axis) and the output torque (vertical axis). When the reduction motor at the input rotates back and forth periodically, the relationship between the output torque and the input torque approximates a hysteresis loop.

[0030] Furthermore, since the two high-strength steel wire ropes in the flexible transmission mechanism are covered with wear-resistant rubber sleeves, the ropes will be subject to friction in the rubber sleeves. Moreover, due to the different bending degrees of the ropes, the friction they are subject to is also non-stationary and nonlinear, and the tension will be lost when it is transmitted in the rubber sleeves. The steel wire rope is also not an ideal rigid body in the axial direction and will have a spring effect. The steel wire rope is considered to have a stiffness of A linear spring, when the rope is in tension, Position pull ,and Deformation of position The relationship is as follows:

[0031]

[0032] Therefore, the displacement at the input end and the displacement at the output end are not exactly the same. Position pull It can be calculated by the following formula:

[0033]

[0034] Where, for The tension of the point, is the Coulomb friction coefficient, For the rope The radius of curvature of a point, for The speed at which the

[0035] Any on the rope Position displacement It can be calculated by the following formula:

[0036]

[0037] The above formula is the calculation formula of tension and displacement derived from physical modeling. In the field of computer control, calculations are usually discretized. In actual controllers, any position on the rope is Position pull It can be calculated by the following formula:

[0038]

[0039] Any on the rope Position displacement It can be calculated by the following formula:

[0040]

[0041] in, , , .

[0042] It can be seen that when the curvature radius of the wire rope is fixed, the tension will decay exponentially.

[0043] In actual use, due to the limitation of operating space, for the sake of ease of operation, the placement and curling of the wire rope are random, that is, the radius of curvature is uncertain, and the tension attenuation of the system is difficult to accurately calculate. If open-loop control is used, the system output has no effect on the control effect. Even if the output deviates, the control effect will not change. Therefore, closed-loop control is adopted here. The output is fed back to the input end through the feedback link and compared with the reference input to form a deviation signal. The control system continuously adjusts the output according to the deviation until the deviation is eliminated or reduced to the allowable range, thereby achieving precise control of the torque. The mathematical expression of closed-loop control is as follows:

[0044]

[0045] In the formula is the sampling sequence number, =0, 1, 2, ..., For the The controller output value at the sampling moment, For the The deviation value input at the sampling moment, is the proportionality coefficient, is the integration coefficient.

[0046] Figure 5 The figure shows the overall structure of the flexible split torque fastening device suitable for narrow places. The operation process is based on Figure 6 The system workflow diagram of the flexible split torque fastening device suitable for narrow areas achieves the coordination of various components:

[0047] The operator can quickly change socket sizes using a magnetic interface, insert it into a bolt through a narrow space, set the target torque, and activate the device. The tightening gun drives the lower drum forward and reverse, transmitting power via two counter-wound steel cables (encased in rubber sheaths). When the bottom ratchet engages the tooth groove, if the drum rotates clockwise, the drive sleeve outputs torque clockwise.

[0048] Both limit devices in this application are mechanical stops that prevent the reaction force from rotating the bolt from rotating the tightening gun and the torque output terminal. This design allows the transmission path to bend freely according to the working space (such as around obstacles or through S-shaped pipes). At the same time, the symmetrical tension of the bidirectional wire rope offsets the deformation caused by one-sided force, ensuring the accuracy and reliability of torque transmission in confined spaces. At the same time, the torque sensor, based on strain gauges or piezoelectric principles, is located on the limit device. When the sleeve drives the bolt to rotate, the reaction force generated acts on the limit device, thereby measuring the actual torque in real time and feeding the signal back to the tightening gun controller to achieve high-precision tightening.

[0049] Figure 7 The torque control algorithm flow chart shows that after setting the target torque, the controller starts the reduction motor and begins monitoring the output torque in real time. The system compares the target torque with the actual output torque and calculates an error signal. This error signal is processed by both proportional and integral control. Proportional control adjusts the control signal based on the error, with the output proportional to the error. Integral control integrates the error and outputs a signal proportional to the integral of the error to eliminate steady-state error. The processed control signals are then added together to drive the reduction motor to adjust the output torque. Simultaneously, a feedback device monitors the output torque in real time and transmits it back to the control system, forming a closed-loop control loop.

[0050] The above embodiments are preferred implementation modes of the present invention, but the implementation modes of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications that do not deviate from the spirit and principles of the present invention should be considered as equivalent replacement methods and are included in the scope of protection of the present invention.

Claims

1. A flexible split torque fastening device suitable for narrow areas, characterized in that: include: A tightening gun, which includes a controller and a power source, wherein the controller is used to receive a target torque value and control the power source to output corresponding power; a flexible transmission mechanism connecting the tightening gun and the torque output terminal for transmitting the power of the tightening gun to the torque output terminal, the flexible transmission mechanism including a flexible force transmission component capable of transmitting torque in a narrow or tortuous space and allowing bending of the torque transmission path; a torque output terminal connected to the flexible transmission mechanism, configured to convert the power transmitted by the flexible transmission mechanism into torque and apply the torque to the fastener, the torque output terminal including a torque feedback device configured to measure the actual applied torque and feed back the signal to the controller, the controller adjusting the output of the power source according to the feedback signal to achieve precise control of the torque; The flexible force transmission component of the flexible transmission mechanism is a bidirectionally wound steel wire rope assembly, the surface of which is wrapped with a wear-resistant rubber sleeve to reduce debris generated by metal friction and rigid resistance during bending; The wire rope assembly includes two high-strength steel ropes, which are wound on the tightening gun end and the drum of the torque output terminal in opposite directions, forming a symmetrical tension structure to ensure the stability of torque transmission during forward and reverse rotation.

2. The torque fastening device according to claim 1, characterized in that: The tightening gun also includes a limit protection device, which is used to trigger a signal to cause the controller to stop the operation of the power source when the movement of the flexible transmission mechanism reaches a preset stroke limit, so as to prevent the flexible transmission mechanism from being overloaded or stuck.

3. The torque fastening device according to claim 1 or 2, characterized in that: The power source is a combination of a servo motor and a gear reducer. The servo motor converts high-speed, low-torque power into low-speed, high-torque output, which is adapted to the power characteristics required for bolt tightening.

4. The torque fastening device according to claim 1, characterized in that: The torque output terminal further includes a ratchet mechanism, which is used to ensure unidirectional output of torque during the tightening process of the bolt to prevent backlash and loosening.

5. The torque fastening device according to claim 4, characterized in that: The sleeve of the torque output terminal is connected to the ratchet mechanism via a magnetic interface, supporting the rapid replacement of bolt heads of various specifications.

6. The torque fastening device according to claim 4 or 5, characterized in that: The torque feedback device is a torque sensor based on a strain gauge or piezoelectric principle. The torque sensor is located on the limit device of the torque output terminal and is used to measure the actual applied torque in real time and feed it back to the controller.

7. The torque fastening device according to claim 6, characterized in that: The controller adopts a closed-loop control algorithm, which feeds back the output to the input end through a feedback link and compares it with the reference input to form a deviation signal. The output is adjusted according to the deviation signal until the deviation is eliminated or reduced to within the allowable range, thereby achieving precise control of the torque.

8. The torque fastening device according to claim 1, characterized in that: It also includes a limit device for preventing the reaction force when rotating the bolt from rotating the tightening gun and the torque output terminal, thereby ensuring the accuracy and reliability of torque transmission.

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