Flexible split type torque fastening device suitable for narrow part

Abstract

The invention discloses a flexible split type torque fastening device suitable for a narrow part. The device comprises a tightening gun, a flexible transmission mechanism and a torque output terminal. A controller is arranged in the tightening gun, an internal motor is started after torque is processed and calculated, the torque is transmitted to a torque output terminal through a flexible transmission mechanism so as to control the tightness of a bolt, and meanwhile, the torque output terminal can feed back the current torque to the controller. The device has the characteristics of detachability and high precision, not only can flexibly adapt to various narrow spaces, but also can accurately control the fastening torque.

Description

Technical Field

[0001] The present invention relates to the field of electromechanical equipment, and particularly to a flexible split torque tightening device applicable to narrow parts. Background Art

[0002] In the field of industrial assembly, the accuracy and reliability of the bolt tightening process directly affect the equipment sealing performance, structural stability and service life. Traditional manual or pneumatic tightening tools have defects such as large torque output deviation, insufficient space adaptability, and lack of real-time feedback. Especially when operating in narrow spaces (such as flange gaps, engine compartments or inside precision electronic equipment), conventional tools often cause torque loss or bolt slipping due to structural interference. The one-way drive of traditional ratchet wrenches relies on frequent manual commutation, resulting in low efficiency, and problems such as cumbersome socket replacement and insufficient anti-slip performance further restrict the assembly quality and efficiency. Summary of the Invention

[0003] Aiming at the deficiencies of large torque deviation and poor space adaptability of traditional bolt tightening tools, the present invention provides a flexible split torque tightening device applicable to narrow parts.

[0004] The present invention includes:

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

[0006] A flexible transmission mechanism, which connects the tightening gun and the torque output terminal, and is used to transmit the power of the tightening gun to the torque output terminal. The flexible transmission mechanism includes a flexible force transmission component, and the flexible force transmission component can transmit torque in a narrow or tortuous space and allow the bending of the torque transmission path;

[0007] A torque output terminal, which connects 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, and the torque feedback device 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] The beneficial effects of the present invention: The present invention realizes technological upgrading through an innovatively developed modular high-precision torque output system. This device innovatively integrates a ratchet mechanism, a dynamic servo closed-loop control component and a steel wire rope flexible cable force transmission mechanism. Through a rigid-flexible coupling transmission mechanism, it realizes the precise output of directional torque in a narrow space, and at the same time supports quick socket replacement, significantly improving the assembly efficiency and reliability, and is applicable to precision industrial scenarios such as large transformers and aviation. Description of the Drawings

[0009] Figure 1 Structural diagram of the tightening gun end

[0010] Figure 2 Structural diagram of the torque output terminal

[0011] Figure 3 Structural diagram of the flexible transmission mechanism

[0012] Figure 4 Torque transmission curve graph

[0013] Figure 5 Overall structural diagram of the device

[0014] Figure 6 Device system working flow chart

[0015] Figure 7 Torque control algorithm flow chart Specific implementation manners

[0016] To make the objectives, technical solutions and advantages of the present invention clearer, the present invention will be further described in detail with reference to the accompanying drawings. Such description introduces specific implementation manners consistent with the principles of the present invention in an illustrative rather than restrictive manner. These implementation manners are described in sufficient detail to enable those skilled in the art to practice the present invention. Other implementation manners can be used and the structures of various elements can be changed and / or replaced without departing from the scope and spirit of the present invention. Therefore, the following detailed description should not be construed in a limiting sense.

[0017] This application provides a flexible split - type torque tightening device applicable to narrow areas. The device consists of a tightening gun, a flexible transmission mechanism, and a torque output terminal. The tightening gun internally contains a controller, which starts the internal motor after processing and calculating the torque, and transmits the torque to the torque output terminal through the flexible transmission mechanism, thereby controlling the tightening and loosening of bolts. At the same time, the torque output terminal can feedback the current torque magnitude to the controller. Different from traditional torque wrenches, this device has the characteristics of being detachable and highly precise, and 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 inside, and realizes high-precision torque output through an intelligent closed-loop system. The controller, as the "brain", includes a microprocessor and a communication module. It can receive the target torque value set by the user and run real-time control algorithms. At the same time, it establishes a data interaction 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 during retraction and extension, a signal is immediately triggered, and the controller stops the motor from running to avoid overloading and straining the transmission mechanism or jamming of the mechanism. The reduction motor set consists of a servo motor and a gear reducer, which converts the high-speed and low-torque of the motor into low-speed and high-torque output to adapt to the power characteristics required for bolt tightening.

[0019] In a preferred embodiment, as Figure 1 shown, the tightening gun end consists of a tightening gun 11, a first sleeve 12, a first reel 13, a limit mechanism 14, a top plate 15 and a bottom plate 16 to form a functional component. Specifically, the output end of the tightening gun 11 adopts a quadrangular prism shaft structure, forming a zero-clearance transition fit with the quadrilateral inner cavity of the first sleeve 12, and the first sleeve 12 and the quadrangular prism boss of the drive shaft of the first reel 13 achieve zero-clearance fit. The first reel 13 is supported by a set of rolling bearings within the rigid frame formed by the top plate 15 and the bottom plate 16. This frame is vertically positioned through copper column and nut assemblies. The limit mechanism 14 is fastened above the top plate via a bolt-nut pair, and its function is to restrict the torque transmission path.

[0020] The device power system integrates a servo controller and a reduction motor set in the body of the tightening gun 11, and establishes a mechanical transmission chain through the first sleeve 12 and the first reel 13. There are two strands of steel wires 21 arranged reversely inside the first reel 13. When the actuator is started, the reduction motor drives the first sleeve 12 to generate a rotational motion, and then drives the first reel 13 to perform a two-way winding operation. The specially designed mechanical limit mechanism 14 effectively suppresses the angular displacement deviation of the tightening gun 11 body caused by the reaction torque generated during the actuation of the first reel 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 integrates a two-way pawl. When the flexible transmission mechanism drives the ratchet input shaft to rotate through the second reel, the meshing mechanism of 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 through a hexagonal magnetic interface, supporting quick replacement of various specifications of bolt heads.

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

[0025] In a preferred embodiment, as Figure 2 shown, the torque output terminal consists of a second reel 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 substrate 38 as the core components. Inside the second reel 31, two symmetrically distributed pre - tightened wire ropes 21 are integrated. Its rotation axis realizes a double - plate support structure through a bearing group. The upper bearing plate and the lower substrate are rigidly fixed by a bolt group. The driving gear 32 and the second reel 31 are connected with zero clearance and form an orthogonal shaft 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 thread pair joint surface can also be provided at the end of the second sleeve 34, and its rotational freedom is restricted by a ratchet mechanism: the pawl 35 has a symmetric double - pawl structure. When the pawl 35 does not engage 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 to drive the rotation of the thread pair; when the pawl 35 system enters the single - side engagement state, the second sleeve 34 is restricted by the ratchet mechanism to only maintain a single - way freedom; and under double - side engagement, the second sleeve 34 will enter a two - way self - locking state.

[0026] The limiter 36 is fixedly connected to the bottom surface of the lower substrate 38 by bolts and adopts a hardened alloy steel block structure to suppress the reaction torque during the actuation of the thread pair through mechanical interference. The power transmission path of the system is that the wire rope 21 drives the second reel 31 to rotate, is transmitted to the second sleeve 34 through the driving gear 32 and the driven gear 33, and finally acts on the thread pair to form a closed - loop torque output system.

[0027] The flexible transmission mechanism is responsible for realizing the flexible transmission and direction conversion of torque in a narrow or tortuous space, and its structure consists of a wire rope assembly with two - way winding and a reel system.

[0028] The main body uses two high - strength wire ropes, the surfaces of which are wrapped with wear - resistant rubber sleeves, which not only prevent the generation of debris due to metal friction but also reduce the rigid resistance during bending; the two wire ropes are wound around two groups of reels at the tightening gun end and the torque output terminal in opposite directions (clockwise / counter - clockwise) to form a symmetric tension structure to ensure the stability of torque transmission during forward and reverse rotations. When the reduction motor of the tightening gun drives the reel at the gun end to rotate, the wire rope generates traction force through winding and unwinding, driving the terminal reel to rotate synchronously, thereby transmitting the torque to the terminal actuator without loss.

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

[0030] Furthermore, due to the two high-strength steel wire ropes in the flexible transmission mechanism, with wear-resistant rubber sleeves wrapped on the surface, the ropes will be subject to frictional forces in the rubber sleeves, and due to the different bending degrees of the ropes, the frictional forces are non-fixed and non-linear, and there will be losses when the tension propagates in the rubber sleeves. The steel wire ropes are not ideal rigid bodies in the axial direction and will have a spring effect. Regarding the steel wire ropes as linear springs with a stiffness of When the rope is in a tensile state, the tension at the position and the deformation at the

[0031]

[0032] Therefore, the displacements at the input end and the output end are not exactly the same. The tension at any position on the rope can be calculated by the following formula:

[0033]

[0034] In the formula, is the tension at point is the Coulomb friction coefficient, is the curvature radius of the rope at point is the velocity at

[0035] The displacement at any position on the rope can be calculated by the following formula:

[0036]

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

[0038]

[0039] The displacement at any position on the rope can be calculated by the following formula:

[0040]

[0041] Where , , .

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

[0043] In actual use, due to the limitation of the operation space, for the sake of simplicity of operation, the placement and curling method of the steel wire rope are random, that is, the curvature radius is uncertain, and the tension decay of the system is difficult to calculate accurately. How to use open-loop control, the system output has no influence on the control action. Even if the output deviates, the control action 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 to achieve 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,..., is the output value of the controller at the th sampling moment, is the deviation value input at the th sampling moment, is the proportional coefficient, is the integral coefficient.

[0046] Figure 5 The overall structure diagram of the flexible split torque tightening device applicable to narrow parts is shown. The operation process is based on Figure 6 the system working flow chart of the flexible split torque tightening device applicable to narrow parts to achieve the coordination of each component:

[0047] The operator can quickly change the sleeve specification through the magnetic interface, put it on the bolt through the narrow space, start the device after setting the target torque, drive the reel below the tightening gun to rotate forward / backward, and transmit power through two reversely wound steel wire ropes (with rubber sleeves outside). When the bottom ratchet engages with the tooth groove, if the reel rotates clockwise, it drives the sleeve to output torque clockwise.

[0048] Both of the two limiting devices in this application are mechanical stoppers, which prevent the tightening gun and the torque output terminal from rotating due to the reaction force when rotating the bolt. This design enables the transmission path to bend freely according to the shape of the working space (such as bypassing obstacles or passing through S-shaped pipes). At the same time, the symmetrical tension of the bidirectional steel wire rope offsets the deformation caused by unilateral force, ensuring the accuracy and reliability of torque transmission in a narrow space. Meanwhile, the torque sensor is based on the strain gauge or piezoelectric principle and is located on the limiting device. When the sleeve drives the bolt to rotate, the generated reaction force acts on the limiting device, thereby measuring the actual acting torque in real time and feeding back the signal to the tightening gun controller to complete high-precision fastening.

[0049] Figure 7 Flowchart of the torque control algorithm. After setting the target torque, the controller starts the reduction motor and begins to monitor the output torque in real time. The system compares the target torque with the actual output torque and calculates the error signal. This error signal is processed through the proportional control and integral control links respectively. The proportional control adjusts the control signal immediately according to the size of the error, and its output is proportional to the error; the integral control performs an integral operation on the error and outputs a signal proportional to the integral of the error to eliminate the steady-state error. The processed control signals are added together to drive the reduction motor to adjust the output torque. At the same time, the feedback device monitors the output torque in real time and transmits it back to the control system to form a closed-loop control.

[0050] The above embodiments are the preferred embodiments of the present invention, but the embodiments of the present invention are not limited to the above embodiments. Any other changes, modifications, substitutions, combinations, and simplifications made without departing from the spirit and principle of the present invention shall be equivalent replacement methods and are all included in the protection scope of the present invention.

Claims

1. A flexible split torque fastening device applicable to narrow parts, characterized in that Comprising: A tightening gun, which internally contains a controller and a power source, and the controller is used to receive a target torque value and control the power source to output corresponding power; A flexible transmission mechanism, which connects the tightening gun and the torque output terminal, and is used to transmit the power of the tightening gun to the torque output terminal. The flexible transmission mechanism includes a flexible force transmission component, and the flexible force transmission component can transmit torque in a narrow or tortuous space and allow the bending of the torque transmission path; A torque output terminal, which connects 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 to be tightened. The torque output terminal includes a torque feedback device, and the torque feedback device is used to measure the actual applied torque and feedback 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.

2. The torque tightening device according to claim 1, wherein, The tightening gun further includes a limit protection device, and the limit protection device is used to trigger a signal to stop the operation of the power source by the controller when the movement of the flexible transmission mechanism reaches a preset stroke limit, so as to prevent the transmission mechanism from being overloaded or jammed.

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

4. The torque tightening device according to claim 1, wherein The flexible force transmission component of the flexible transmission mechanism is a bidirectionally wound wire rope assembly, and the surface of the wire rope assembly is wrapped with a wear-resistant rubber sleeve to reduce the debris generated by metal friction and the rigid resistance during bending.

5. The torque tightening device according to claim 4, characterized in that, The wire rope assembly includes two high-strength wire ropes, and the two wire ropes are respectively wound around the drums at the tightening gun end and the torque output terminal in opposite directions to form a symmetric tension structure, ensuring the stability of torque transmission during forward and reverse rotations.

6. The torque tightening device according to claim 1, characterized in that, The torque output terminal further includes a ratchet mechanism, and the ratchet mechanism is used to ensure the unidirectional output of torque during the bolt tightening process and prevent back-off and loosening.

7. The torque tightening device according to claim 6, wherein The second sleeve of the torque output terminal is connected to the ratchet mechanism through a magnetic interface, supporting the quick replacement of bolt heads of various specifications.

8. The torque tightening device according to claim 6 or 7, characterized in that, The torque feedback device is a torque sensor based on the strain gauge or piezoelectric principle, and 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 feedback it to the controller.

9. The torque tightening device according to claim 8, characterized in that, The controller adopts a closed-loop control algorithm, and through the feedback link, the output is fed back to the input end to be compared with the reference input to form a deviation signal, and the output is adjusted according to the deviation signal until the deviation is eliminated or reduced to an allowable range, realizing precise control of the torque.

10. The torque tightening device according to claim 1, characterized in that, It further includes a limit device, which is used to prevent the tightening gun and the torque output terminal from rotating due to the reaction force when rotating the bolt, ensuring the accuracy and reliability of torque transmission.

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