Thread tension adjusting device and sewing machine

Abstract

The invention discloses a thread tension adjusting device and a sewing machine, relates to the technical field of sewing equipment, and aims to solve the problems that an existing electromagnet-driven thread tension adjusting device is low in response speed, thread tension is reduced due to long-time operation, and the thread loosening speed lags behind. The motor is arranged on one side of the supporting structure; the wire clamping mechanism and the motor are oppositely arranged on the other side of the supporting structure, the wire clamping mechanism comprises a cam and a wire passing wheel, the cam is connected with a motor shaft of the motor, and the outer edge of the cam is attached to a wire passing groove of the wire passing wheel; by means of the arrangement, high-precision, quick-response and long-term stable thread tension control is achieved through motor driving, meanwhile, the thread loosening performance is optimized, and the overall performance of the sewing machine is remarkably improved.

Description

TECHNICAL FIELD

[0001] The present application relates to the sewing equipment technical field, more particularly, to a thread tension adjusting device and a sewing machine. BACKGROUND

[0002] The thread tension control precision of a sewing machine is a key factor affecting the stitch quality and appearance flatness of a sewing product, and directly determines the sewing efficiency and product qualification rate. In existing industrial and household sewing machines, the thread tension adjusting device mostly adopts an electromagnet drive, and its working mode is mainly divided into two types: one is a pushing type, in which, in a normal state, a tension spring is in a compressed state, tightly pressing the thread clamping pieces together to provide clamping force; when it is necessary to loosen, the electromagnet pushes away the top rod to separate the thread clamping pieces, so as to achieve the purpose of loosening the thread. The other is a pulling type, in which, in a normal state, the thread clamping pieces are not clamped, and the electromagnet pulls the thread clamping pieces to clamp them after being powered on, so as to provide clamping force.

[0003] However, although the above two schemes are widely used in sewing machines, there are still many technical shortcomings in actual operation. First, the current thread tension control scheme mainly relies on an electromagnet as a driving force, but the response speed of the electromagnet is generally about 20 ms, which is much slower than the response speed of the motor (below 5 ms). In the high-speed sewing scene, the hysteresis of the electromagnet magnetic force change will cause the thread tension adjustment to be out of sync with the sewing rhythm, and finally the stitch quality cannot meet the expected standard. Second, in the process of long-time continuous power-on operation of the electromagnet, the coil inside the electromagnet will generate heat accumulation due to the current heat effect, resulting in a significant increase in the temperature of the electromagnet body. Since the magnetic force of the electromagnet is directly related to the magnetic permeability of the coil, and the magnetic permeability will decay with the increase of the temperature, the electromagnetic suction force output by the electromagnet will weaken. The attenuation of the electromagnetic suction force will directly change the clamping pressure of the thread clamping part on the thread, causing the thread tension to deviate from the preset value. In addition, the loosening process realized by relying on the spring force is limited by the rebound speed of the spring, and the response speed lags behind the sewing action rhythm. At the same time, the residual spring force may cause a weak clamping force between the thread clamping pieces, causing the thread to be dragged, affecting the smoothness of the thread end processing and fabric transfer.

[0004] Therefore, how to solve the problems of slow response speed, long-time operation leading to reduced thread tension, and slow loosening speed of the existing electromagnet-driven thread tension adjusting device is a problem that needs to be solved by the technical personnel in the field. SUMMARY

[0005] Therefore, the purpose of the present application is to provide a thread tension adjusting device, which realizes high-precision, fast-response and long-term stable thread tension control through motor driving, and optimizes the loosening performance.

[0006] Another object of the present application is to provide a sewing machine comprising the thread tension adjusting device, which significantly improves the overall performance of the sewing machine.

[0007] To achieve the above object, the present application provides the following technical solutions.

[0008] A thread tension adjusting device, comprising:

[0009] A support structure;

[0010] A motor arranged on one side of the support structure;

[0011] A thread clamping mechanism arranged on the other side of the support structure opposite to the motor, the thread clamping mechanism comprising a cam and a thread guide wheel, the cam being connected with a motor shaft of the motor, and the outer edge of the cam being in contact with a thread guide groove of the thread guide wheel.

[0012] In some embodiments, the thread clamping mechanism further comprises a resilient element, which is used to connect the thread guide wheel with the support structure and provide a restoring force for the thread guide wheel.

[0013] In some embodiments, the thread clamping mechanism further comprises a crank, the rotating end of the crank being rotatably connected with the support structure through a crank shaft, and the movable end being movably arranged in a first limiting hole of the support structure through a limiting shaft hinged by a bearing.

[0014] In some embodiments, the limiting shaft is provided with a thread tension spring at the end away from the support structure, the thread guide wheel is arranged outside the thread tension spring, and the thread guide wheel is provided with a second limiting hole through which a thread tension part of the thread tension spring passes.

[0015] In some embodiments, the resilient element is a tension spring, the side of the crank close to the support structure is provided with a protrusion, the side of the support structure close to the crank is provided with a hook spring column, and the two ends of the tension spring are connected with the protrusion and the hook spring column through hooking structures respectively.

[0016] In some embodiments, the outer edge of the cam is provided with a thread clamping ring having elasticity.

[0017] In some embodiments, a pressure sensor is arranged in the thread guide groove, which is used to detect the pressure of the outer edge of the cam or the thread clamping ring on the thread guide groove in real time.

[0018] In some embodiments, the outer contour of the cam is in the shape of an Archimedes spiral.

[0019] In some embodiments, the thread guide groove is an arc-shaped groove.

[0020] A sewing machine comprising the thread tension adjusting device according to any one of the above.

[0021] The thread tension adjusting device provided by the application comprises a support structure, a motor and a thread clamping mechanism. Specifically, the motor is arranged on one side of the support structure, and the thread clamping mechanism is arranged on the other side of the support structure opposite to the motor. The device can effectively utilize space, has a smaller volume, is convenient to integrate into various sewing machines, and improves the versatility and adaptability of the equipment. The thread clamping mechanism comprises a cam and a thread guide wheel. The outer edge of the cam is in close contact with the thread guide groove of the thread guide wheel, so that precise mechanical transmission can be achieved. Through rotation of the cam, the radial movement of the thread guide wheel forms a linear relationship with the rotation angle of the cam, so that continuous adjustment of the thread tension can be realized. At the same time, the close transmission mode effectively avoids the thread tension fluctuation caused by transmission gap or sliding, and ensures the uniformity and stability of the thread tension during sewing. In addition, by changing the rotation angle of the cam, the position of the thread guide wheel can be flexibly adjusted, and then different sizes of thread tension can be realized to adapt to the needs of various sewing processes. The close transmission also reduces the sliding friction between the transmission components, reduces the wear speed of the components, prolongs the service life of the device, and reduces the maintenance cost.

[0022] The cam is connected with the motor shaft of the motor, ensuring the directness and efficiency of power transmission, reducing the intermediate transmission link, and thus reducing energy loss and transmission error. The precise control capability of the motor can be directly reflected on the rotation of the cam. Through the speed regulation and positioning function of the motor, precise rotation of the cam can be realized, and then the thread tension can be accurately adjusted. The motor can provide precise speed and torque control, ensuring that the rotation angle and speed of the cam can be accurately adjusted according to actual needs, so as to realize high-precision adjustment of the thread tension. In addition, the response speed of the motor is much higher than that of the traditional electromagnet driving mode, which can quickly adjust the thread tension during sewing to adapt to the needs of high-speed sewing and avoid needle trace quality problems caused by response lag. During operation, the motor has the characteristics of low energy consumption and low heat generation, and will not cause performance degradation due to long-time operation, thereby effectively ensuring the long-term stability of the thread tension. At the same time, the motor-driven quick thread release mechanism uses the fast response capability of the motor to realize instant thread release, avoiding the response lag problem caused by the rebound speed limitation of the traditional tension spring. In addition, through the precise control of the motor, zero residual force can be realized during thread release, effectively avoiding the weak clamping force between the thread clamping pieces caused by the residual elastic force of the tension spring, and then ensuring the smoothness of the thread release process.

[0023] The thread tension adjusting device arranged in the above manner realizes high-precision, fast-response and long-term stable thread tension control through motor driving, optimizes the thread release performance, and significantly improves the overall performance of the sewing machine. BRIEF DESCRIPTION OF DRAWINGS

[0024] In order to more clearly illustrate the technical solutions in the embodiments of the present application or the prior art, the following will briefly introduce the drawings needed to be used in the embodiments or prior art description. Obviously, the drawings described below only illustrate a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0025] Figure 1 Structure diagram of the line tension adjusting device provided by the present application;

[0026] Figure 2 Partial structure diagram of the line tension adjusting device provided by the present application;

[0027] Figure 3 Exploded view of Figure 2

[0028] Structure diagram of the line tension adjusting device provided by the present application; Figure 4

[0029] Structure diagram of the line tension adjusting device provided by the present application; Figure 5

[0030] Flow chart of line tension detection and control of the line tension adjusting device provided by the present application. Figure 6

[0031] Reference signs:

[0032] 1-supporting structure, 11-first limiting hole, 12-hook spring column;

[0033] 2-motor, 21-motor shaft;

[0034] 3-thread clamping mechanism, 31-cam, 32-thread passing wheel, 321-thread passing groove, 322-second limiting hole, 33-elastic element, 34-crank, 341-protrusion, 35-crank shaft, 36-bearing, 37-limiting shaft, 38-thread tension spring, 39-thread clamping loop. DETAILED DESCRIPTION

[0035] The technical solutions in the embodiments of the present application will be described clearly and completely below with reference to the drawings in the embodiments of the present application. Obviously, the described embodiments are only a part of the embodiments of the present application, and not all the embodiments. Based on the embodiments of the present application, all the other embodiments obtained by a person of ordinary skill in the art without creative effort belong to the protection scope of the present application.

[0036] ​In the present application, unless otherwise explicitly specified and limited, the terms "mounting", "connecting", "connecting", "fixing" and the like should be understood broadly, for example, it can be fixedly connected, or it can be detachably connected, or it can be integrally connected; it can be mechanically connected, or it can be electrically connected; it can be directly connected, or it can be indirectly connected through an intermediate medium, or it can be connected inside two elements. For those skilled in the art, the specific meaning of the above terms in the present application can be understood according to the specific circumstances.

[0037] The core of the present application is to provide a thread tension adjusting device, which realizes high-precision, fast response and long-term stable thread tension control through motor 2 driving, and optimizes the thread loosening performance. Another core of the present application is to provide a sewing machine comprising the above thread tension adjusting device, which significantly improves the overall performance of the sewing machine.

[0038] Please refer to Figure 1 , Figure 2 and Figure 4 , a thread tension adjusting device comprises a support structure 1, a motor 2, and a thread clamping mechanism 3.

[0039] Specifically, the motor 2 is arranged on one side of the support structure 1, and the thread clamping mechanism 3 is arranged on the other side of the support structure 1 opposite to the motor 2, which can effectively utilize the space, make the device smaller, facilitate integration into various sewing machines, and improve the versatility and adaptability of the equipment. The thread clamping mechanism 3 comprises a cam 31 and a thread guide wheel 32, the outer edge of the cam 31 is in close contact with the thread guide groove 321 of the thread guide wheel 32, which can realize precise mechanical transmission. Through the rotation of the cam 31, the radial movement of the thread guide wheel 32 and the rotation angle of the cam 31 form a linear relationship, so as to realize the continuous adjustment of the thread tension. At the same time, this close transmission mode effectively avoids the tension fluctuation caused by transmission gap or sliding, and ensures the uniformity and stability of the thread tension in the sewing process. In addition, by changing the rotation angle of the cam 31, the position of the thread guide wheel 32 can be flexibly adjusted, and then different sizes of thread tension can be realized to adapt to the needs of various sewing processes. Close transmission also reduces the sliding friction between transmission parts, reduces the wear speed of parts, prolongs the service life of the device, and reduces the maintenance cost.

[0040] The cam 31 is connected with the motor shaft 21 of the motor 2, ensuring the directness and high efficiency of power transmission, reducing the intermediate transmission link, thereby reducing energy loss and transmission error. The precise control capability of the motor 2 can be directly reflected in the rotation of the cam 31, and through the speed regulation and positioning function of the motor 2, the precise rotation of the cam 31 can be realized, and the line tension can be accurately adjusted. The motor 2 can provide precise speed and torque control to ensure that the rotation angle and speed of the cam 31 can be accurately adjusted according to actual needs, thereby realizing high-precision adjustment of the line tension. In addition, the response speed of the motor 2 is much higher than that of the traditional electromagnet driving mode, which can quickly adjust the line tension during sewing to adapt to the needs of high-speed sewing and avoid needle trace quality problems caused by response lag. During operation, the motor 2 has the characteristics of low energy consumption and low heat generation, and will not cause performance degradation due to long-time operation, thereby effectively ensuring the long-term stability of the line tension. At the same time, the motor 2 driven quick thread releasing mechanism uses the fast response capability of the motor 2 to realize instant thread release, avoiding the response lag problem caused by the speed limitation of the traditional tension spring elastic force. In addition, through the precise control of the motor 2, zero residual force can be achieved during thread release, effectively avoiding the weak clamping force between the clamping pieces caused by the residual elastic force of the tension spring, thereby ensuring the smoothness of the thread release process.

[0041] In the above case, the wire passing groove 321 is an arc-shaped groove. Specifically, the wire passing groove 321 is designed as an optional circular arc-shaped groove or a "V"-shaped arc groove, and this flexible design enables the device to be adapted to different sewing materials and process requirements. The circular arc-shaped groove can provide more uniform clamping force when handling soft or thin wires, reducing wire wear; while the "V"-shaped arc groove is more suitable for thick or high-strength sewing threads, providing more stable clamping effect. This flexibility significantly improves the versatility and application range of the device. Among them, the circular arc-shaped groove is the preferred design, which can better fit the circular cross-section of the sewing thread, reducing stress concentration of the wire during clamping, thereby reducing the risk of wire breakage and improving the stability of the sewing thread delivery. At the same time, the "V"-shaped groove can also provide good clamping effect in actual application, especially when handling thicker wires, it can ensure that the wire does not shift during clamping, further optimizing the wire clamping performance.

[0042] In one embodiment, the cam 31 is directly provided with a circular arc flange or a V-shaped flange matched with the wire passing groove 321, which can ensure the precise positioning of the wire during delivery. The circular arc flange cooperates with the circular arc surface wire passing groove 321, and the V-shaped flange cooperates with the corresponding designed wire passing groove 321, both of which can provide stable clamping force, reducing the deviation or shaking of the wire during delivery, thereby improving the accuracy and stability of the wire delivery.

[0043] In another embodiment, the outer edge of the cam 31 is provided with an elastic wire clamping ring 39. The outer edge of the cam 31 is provided with an elastic wire clamping ring 39 and is embedded through an adaptive slot. This design not only enhances the flexibility of clamping, but also adapts to wires of different diameters and materials. The elastic wire clamping ring 39 can automatically adjust the clamping force according to the thickness of the wire, avoiding damage to the wire due to excessive clamping force, or sliding of the wire due to insufficient clamping force, thereby significantly improving the adaptability of the device to different sewing threads. The wire passing groove 321 on the thread guide wheel 32 matches the curvature of the outer circle of the wire clamping ring 39, forming a fitting assembly relationship. This design not only ensures smooth transition of the wire during transportation, but also reduces friction between the wire and the wire passing groove 321, reducing the risk of wire wear and tear, prolonging the service life of the wire, and improving the smoothness of the sewing process. Through the fitting assembly of the circular arc surface and the wire clamping ring 39, the wire can maintain stable positioning during transportation, avoiding uneven stitches or sewing failures caused by wire deviation.

[0044] In the above embodiment, a pressure sensor is provided in the wire passing groove 321 to detect the pressure of the outer edge of the cam 31 or the wire clamping ring 39 on the wire passing groove 321 in real time.

[0045] It can be understood that the pressure sensor provided in the wire passing groove 321 can detect the pressure of the outer edge of the cam 31 or the wire clamping ring 39 on the wire passing groove 321 in real time. This real-time monitoring function enables the device to obtain relevant data of the wire tension in real time, providing a basis for dynamic adjustment. By calculating the sliding friction of the wire through pressure data, the size of the wire tension can be accurately determined, thereby realizing dynamic adjustment of the wire tension and ensuring that the wire tension is always within the preset range. The dynamic adjustment mechanism can effectively deal with fluctuations in wire tension caused by changes in wire, fluctuations in sewing speed, or mechanical vibrations during the sewing process. Through real-time feedback and adjustment, the device can quickly correct deviations and maintain stable wire tension, avoiding problems such as uneven stitches, thread skipping, or thread breakage caused by unstable tension, thereby significantly improving sewing quality.

[0046] When detecting the wire tension, the pressure sensor is preferred for measurement: the pressure sensor detects the pressure of the wire clamping ring 39 acting on the wire passing groove 321 in real time, and combined with the friction force calculation formula, the sliding friction of the wire can be accurately calculated, and the size of the wire tension can be determined. In addition, another detection scheme can also be used, that is, by detecting the displacement of the thread tension spring 38 and calculating its restoring force based on the mechanical properties of the thread tension spring 38, the wire tension can be accurately detected. This method is not described in detail, please refer to the prior art. Both detection schemes can be flexibly selected according to actual application scenarios to meet different sewing processes and equipment requirements.

[0047] The line tension adjusting device is driven by the motor 2 to achieve high-precision, fast response and long-term stable line tension control, and optimizes the thread loosening performance, thereby significantly improving the overall performance of the sewing machine.

[0048] Please refer to Figure 2 、 Figure 3 and Figure 5 , the thread clamping mechanism 3 further comprises a resilient element 33 connected between the thread guide wheel 32 and the support structure 1, for providing a restoring force to the thread guide wheel 32.

[0049] It should be noted that the resilient element 33 connects the thread guide wheel 32 and the support structure 1, and provides a stable restoring force to the thread guide wheel 32, so as to ensure that the thread guide wheel 32 can quickly and accurately return to the initial position during the adjustment of the line tension or the thread loosening, and avoid the instability of the line tension or the thread clamping failure caused by the position deviation. The restoring force of the resilient element 33 can offset part of the inertial force and friction force in the mechanical transmission, so that the movement of the thread guide wheel 32 driven by the cam 31 is more stable. This stability helps to improve the accuracy of the line tension adjustment, and ensures that the line tension can remain consistent under different working conditions. The addition of the resilient element 33 reduces the impact and vibration of the thread guide wheel 32 during movement, and reduces the wear rate of mechanical parts. This design not only prolongs the service life of the device, but also reduces the risk of failure caused by component fatigue, and improves the overall reliability of the device. During the thread loosening process, the resilient element 33 can quickly reset the thread guide wheel 32, ensuring that the wire can be quickly released. This fast response capability avoids the problems of thread handling difficulty or fabric transfer difficulty caused by delayed thread loosening, and improves the smoothness of the sewing process.

[0050] In the above case, the thread clamping mechanism 3 further comprises a crank 34, the rotating end of the crank 34 is rotatably connected to the support structure 1 through a crank shaft 35, and the movable end is movably arranged in the first limiting hole 11 of the support structure 1 through a limiting shaft 37 hinged by a bearing 36.

[0051] It can be understood that the crank 34 is rotationally connected with the support structure 1 through the crank shaft 35, ensuring the stability and accuracy of its rotational movement. This connection mode can accurately transmit the power of the motor 2 to drive the thread wheel 32 to realize the expected radial movement, thereby realizing the accurate adjustment of the thread tension. The movable end of the crank 34 is movably arranged in the first limiting hole 11 of the support structure 1 through the bearing 36 hinged limiting shaft 37, which provides a clear path and range for the movement of the thread wheel 32. The cooperation of the limiting shaft 37 and the limiting hole can effectively constrain the motion trajectory of the thread wheel 32, avoid its deviation or jamming during adjustment, and ensure the flexibility and reliability of the movement. The connection between the crank 34 and the limiting shaft 37 through the bearing 36 significantly reduces the friction between the moving parts, reduces mechanical wear. This low-friction design not only prolongs the service life of the components, but also improves the operating efficiency of the device and reduces energy consumption. The double support structure 1 of the crank shaft 35 and the limiting shaft 37 provides a stable mechanical basis for the movement of the thread wheel 32. This design can effectively resist external impact and vibration, ensuring that the device can maintain stable performance under high-speed operation or complex working conditions.

[0052] The movement of the crank 34 can quickly respond to the driving signal of the motor 2 through the precise cooperation of the limiting shaft 37 and the limiting hole, realizing instant thread tension adjustment. This fast response capability enables the device to adapt to the needs of high-speed sewing, avoiding needle trace quality problems caused by adjustment lag. The combined design of the crank 34 and the limiting shaft 37 simplifies the mechanical transmission structure, reducing the use of complex connecting rods and sliding block mechanisms. This simplification not only reduces the manufacturing cost of the device, but also improves the convenience of maintenance and repair, reducing downtime. The cooperation of the crank 34 and the limiting shaft 37 can be adjusted according to different sewing process requirements, providing appropriate movement range and adjustment accuracy. This adaptability enables the device to better cope with different thread materials and sewing speeds, enhancing the versatility and flexibility of the device.

[0053] The support structure 1 mainly includes a mounting disc, which serves as the core framework of the entire device and provides a stable mounting basis for various components. The cam 31 is positioned in the mounting hole of the mounting disc through the motor shaft 21, and the two constitute rotating pair one, which can rotate relative to the axis of the motor shaft 21. This design ensures that the cam 31 can rotate smoothly and accurately under the drive of the motor 2, providing a power basis for subsequent line tension adjustment. One end of the crank 34 is positioned in the crank shaft hole of the mounting disc through the crank shaft 35, and the two constitute rotating pair two, which can rotate relative to the axis of the crank shaft 35. This double rotating pair design allows the crank 34 to realize complex motion conversion under the drive of the cam 31, converting the rotational motion of the cam 31 into the radial movement of the line wheel 32. The other end of the crank 34 is in interference fit with the inner ring of the bearing 36, ensuring tight connection and stable force transmission between the two. The limiting shaft 37 passes through the inner ring of the bearing 36 and the central shaft hole of the line wheel 32 in sequence, realizing coaxial assembly of the three. This coaxial assembly not only simplifies the structure design, but also improves the efficiency and accuracy of motion transmission.

[0054] The line wheel 32 is connected to the crank 34 through the limiting shaft 37 and can move synchronously with the crank 34. This linkage design ensures that the movement of the line wheel 32 is closely matched with the rotation of the cam 31, achieving dynamic adjustment of the line tension. One end of the limiting shaft 37 is embedded in the limiting hole of the mounting disc, and the hole diameter and depth of the limiting hole are designed to be accurately matched with the outer diameter and length of the limiting shaft 37. Through this limiting structure, the movement range of the limiting shaft 37 and the components connected to it, such as the bearing 36 and the line wheel 32, is strictly limited within the preset track. This design effectively avoids device operation failure caused by component movement offset, ensuring the stability and reliability of the entire device.

[0055] Please refer to Figure 2 , Figure 3 and Figure 4 , the limiting shaft 37 away from the support structure 1 is provided with a thread tension spring 38, and the line wheel 32 is located outside the thread tension spring 38. The line wheel 32 is provided with a second limiting hole 322 for the thread tension part of the thread tension spring 38 to pass through.

[0056] It should be noted that the thread tension spring 38 is fixed in the thread guide wheel 32, and the thread tension part extends through the second limiting hole 322, which is compatible with the trajectory of the thread movement. This design can achieve precise thread hooking during device operation, ensuring that the thread maintains stable tension during transportation, avoiding uneven stitches or sewing failures caused by loose or shaking threads. The end of the limiting shaft 37 away from the support structure 1 is provided with the thread tension spring 38, which can provide stable support during operation. The coaxial assembly of the limiting shaft 37 and the thread guide wheel 32, as well as the fixed connection of the thread tension spring 38 and the thread guide wheel 32, ensures the mechanical stability of the entire thread hooking mechanism during operation, reducing the risk of failure caused by loose or displaced parts.

[0057] Please refer to Figure 2 and Figure 5 , the elastic element 33 is a tension spring, the crank 34 is provided with a protrusion 341 on one side close to the support structure 1, and the support structure 1 is provided with a hook spring column 12 on one side close to the crank 34. The two ends of the tension spring are connected to the protrusion 341 and the hook spring column 12 through hooking structures respectively.

[0058] It can be understood that in the structural design of the device, a protrusion 341 is ingeniously arranged at the end of the crank 34. This protrusion 341 is closely connected to one end of the tension spring, allowing the tension spring to provide a stable return force in the direction of rotation of the crank 34. The key role of this design is to ensure that the crank 34 can quickly and stably reset after completing the movement, thereby maintaining the running stability of the entire device and the accuracy of thread tension adjustment. The tension spring, as the elastic element 33, is connected to the protrusion 341 of the crank 34 and the hook spring column 12 of the support structure 1 through hooking structures at both ends, forming a stable tension return circuit. This design ensures that the crank 34 can obtain a continuous and stable resetting force during movement, allowing the thread guide wheel 32 to quickly and accurately return to the initial position, avoiding unstable thread tension or thread clamping failure caused by position deviation. Through this path, the tension spring can continuously apply a return force to the crank 34, ensuring that the crank 34 is always properly constrained and guided during movement. By reasonably adjusting the elastic coefficient and deformation range of the tension spring, it can flexibly adapt to the needs of different sewing materials and processes for thread tension, thereby achieving efficient and stable sewing operations.

[0059] The three-way linkage of "cam 31, crank 34, tension spring" precisely controls the thread tension. The rotational movement of cam 31 is transmitted to the tension spring through crank 34, which in turn drives the thread guide wheel 32 to move radially, achieving dynamic adjustment of thread tension. The outer contour of the thread clamping ring 39 closely fits the thread guide groove 321. This design ensures that the pressure is evenly distributed inside the thread guide groove 321, avoiding fluctuations in thread tension caused by uneven local pressure, thereby ensuring the uniformity and stability of thread tension during sewing. This linkage mechanism not only improves the accuracy and response speed of thread tension adjustment, but also enhances the adaptability of the device to different sewing materials and process requirements, significantly improving sewing quality and efficiency.

[0060] As a preferred embodiment, the outer contour of the cam 31 is in the shape of an Archimedes spiral. Designing the outer contour of the cam 31 as an Archimedes spiral ensures a precise linear correspondence between the rotation angle of the cam 31 and the radial displacement of the thread guide wheel 32. This design ensures that the distance from the outer contour of the cam 31 to the axis changes uniformly when the cam 31 rotates, directly translating into the linear increase and decrease of the squeezing force between the thread guide wheel 32 and the thread clamping ring 39. This linear variation relationship makes the adjustment of thread tension more accurate and continuous, enabling high-precision thread tension control to meet the fine-tuning requirements of thread tension for different sewing processes. The uniform rotation of the cam 31 enables continuous adjustment of thread tension, avoiding problems such as uneven stitches and thread skipping caused by discontinuous adjustment, significantly improving sewing quality. The design of the Archimedes spiral allows the device to flexibly adjust thread tension according to different sewing speeds, thread types, and process requirements. By changing the rotation angle of the cam 31, smooth transitions from low tension to high tension can be achieved, adapting to various sewing scenarios and enhancing the versatility and flexibility of the device.

[0061] The outer contour of the cam 31 is designed with the center of the revolute pair (i.e. the axis of the motor shaft 21) as the origin, adopting an Archimedes spiral structure. This design makes the distance between any point on the outer contour of the cam 31 and the center of the revolute pair change regularly. Specifically, the planar Cartesian coordinate equation of this Archimedes spiral is: , where α and β can be adjusted according to actual conditions, with α taking 0 and β taking 2 in this patent. The design of this Archimedes spiral structure enables the cam 31 to precisely control the stretching length of the tension spring during rotation, thereby achieving continuous adjustment of thread tension. By adjusting α and β, different thread tension requirements can be flexibly adapted to, ensuring that the device maintains stable performance under various sewing conditions. In addition, this scheme is not limited to the Archimedes spiral structure. Other contour curves that meet functional requirements, such as "variable-diameter circular arc spiral" and "elliptical arc combination", can also achieve precise control of the stretching length of the tension spring, thereby achieving the same adjustment effect.

[0062] The working principle of the device is as follows: the cam 31 can realize rotary motion around the rotary pair one (i.e. the axis of the motor shaft 21). Since the distance from each point on the outer contour of the cam 31 to the center of the rotary pair one changes regularly according to the Archimedes spiral, when the cam 31 rotates in the counterclockwise direction, the outer contour will generate a radial extrusion force on the thread wheel 32, prompting the thread wheel 32 to move away from the motor shaft 21. In this process, the thread wheel 32 is linked with the crank 34 through the limiting shaft 37, and the movement of the thread wheel 32 will drive the crank 34 to rotate synchronously around the rotary pair two (i.e. the axis of the crank shaft 35), and then make the tension spring connected with the protrusion 341 at the end of the crank 34 be stretched. The tension spring generates elastic restoring force after being stretched, and the restoring force acts on the crank 34 in the form of tension, forming the reset pre-tightening force of the crank 34. With the movement of the thread wheel 32 away from the motor shaft 21, the gap between the thread groove 321 on the thread wheel 32 and the thread clamp 39 gradually decreases, and finally forms a extrusion fit relationship. The sewing thread passes through the gap between the thread groove 321 and the thread clamp 39, and under the above extrusion action, the wire is tightly clamped between them. In the normal sewing process of the sewing machine, when the wire moves along the preset path, it will produce relative sliding with the arc surface of the thread groove 321 and the inner wall of the thread clamp 39, and then form sliding friction. The sliding friction is the source of thread tension in the sewing process, which can ensure the stability of the thread tension and avoid problems such as thread jumping and loose stitches.

[0063] Further, the angle of the cam 31 rotating counterclockwise is positively correlated with the size of the wire tension. When the angle of the cam 31 rotating counterclockwise increases, the extrusion stroke of the cam 31 to the wire guide wheel 32 increases, the stretching amount of the tension spring increases accordingly, and the tension of the tension spring acting on the crank 34 increases. Driven by the tension, the extrusion force of the wire guide groove 321 and the wire clamping ring 39 to the wire increases synchronously, which significantly increases the sliding friction between the wire and the two, and finally makes the wire tension show an increasing trend. Conversely, if the wire tension needs to be reduced, the cam 31 can be driven to rotate clockwise around the first rotating joint (the axis of the motor shaft 21) to achieve the purpose. When the cam 31 rotates clockwise, the radial extrusion force of the cam 31 to the wire guide wheel 32 gradually weakens. Since the outer contour of the cam 31 follows the Archimedes spiral rule, during the clockwise rotation, the distance between the outer contour and the center of the first rotating joint decreases with the increase of the rotation angle. At this time, the tension spring gradually contracts under the action of its elastic restoring force, and the tension acting on the crank 34 decreases synchronously. Influenced by the change of the tension, the crank 34 moves towards the motor shaft 21 around the second rotating joint, and then drives the wire guide wheel 32 to move towards the motor shaft 21 through the limiting shaft 37. As the wire guide wheel 32 moves towards the motor shaft 21, the extrusion force of the wire guide groove 321 and the wire clamping ring 39 to the wire passing through the gap decreases significantly. When the wire moves along the preset path, the sliding friction between the wire and the arc surface of the wire guide groove 321 and the inner wall of the wire clamping ring 39 decreases, and finally the wire tension in the wire conveying process is effectively reduced to adapt to the process requirement of low-tension wire conveying in the sewing operation.

[0064] Please refer to Figure 6 The wire tension detection and control process of the present application is as follows: the user first inputs the desired tension value. The pressure sensor detects the pressure in real time, and calculates the friction force (i.e. the real-time wire tension) according to the formula. Then, the real-time wire tension is fed back to the comparator to compare with the preset tension size to obtain the deviation. The controller issues instructions to drive the motor 2 to act according to the deviation, thereby adjusting the tension of the wire. Then, the pressure sensor detects again and repeats the above process to form a closed loop control, so as to realize accurate and stable control of the wire tension.

[0065] The outer contour of the cam 31 of the device adopts an Archimedes spiral design, and the distance from each point on the contour to the center of the rotary pair changes linearly, thereby realizing the precise correspondence between the rotation angle of the cam 31 and the displacement of the thread passing wheel 32. When the motor 2 drives the cam 31 to rotate clockwise or counterclockwise, the thread tension will show a continuous and linear adjustment trend with the change of the rotation angle of the cam 31. This precise adjustment characteristic can meet the fine requirements of different fabrics on the thread tension, thereby significantly improving the uniformity and aesthetics of the sewing stitches. The rotation of the cam 31 is directly driven by the motor 2, and the response speed is greatly improved. The transmission structure of the cam 31 and the thread passing wheel 32 is rigid contact, and the response time from the start of the rotation of the cam 31 to the stable adjustment of the thread tension can be controlled within 20 ms, which can quickly adapt to the dynamic tension adjustment demand of the sewing machine during high-speed operation. When it is necessary to quickly loosen the thread, the motor 2 only needs to rotate clockwise quickly, so that the extrusion force between the thread passing wheel 32 and the thread clamping ring 39 is reduced to 0, thereby further improving the response efficiency of the device. In addition, the operation energy consumption of the device is low and the heat generation is small. During the thread tension adjustment process, the cam 31 only needs to be rotated at the time of tension switching, and after the tension is stable, the motor 2 can enter the standby state without the need for continuous power output, thereby significantly reducing the energy consumption and making the operation more energy-saving and environmentally friendly. Finally, when the cam 31 rotates to the target position and remains fixed, the radial extrusion force of the outer contour of the cam 31 on the thread passing wheel 32 remains constant, and the stretching amount of the tension spring also remains stable. This makes the clamping and extrusion force of the thread passing groove 321 and the thread clamping ring 39 on the thread maintain at a preset constant value. In this state, the sliding friction force generated between the thread and the thread passing groove 321 and the thread clamping ring 39 during the conveying process always remains consistent, that is, the thread tension is in a stable and constant state without any fluctuation deviation, thereby ensuring the stability and consistency of the sewing process.

[0066] In summary, the thread tension adjustment device provided by the present application performs well in terms of high precision, fast response, low energy consumption and stability, and provides an efficient and reliable thread tension control solution for sewing operations, thereby significantly improving the sewing quality and production efficiency.

[0067] In addition to the thread tension adjustment device disclosed in the above embodiments, the present application also provides a sewing machine comprising the above thread tension adjustment device. The structures of other parts of the sewing machine refer to the prior art, and will not be described herein.

[0068] It should be noted that in the present specification, relational terms such as first and second are used only to distinguish one entity from another entity, and do not necessarily require or imply that there is any such actual relationship or order between these entities.

[0069] The various embodiments are described in the specification, each of which focuses on differences from other embodiments. The same or similar parts among the various embodiments can be mutually referred to.

[0070] The above describes in detail the thread tension adjusting device and sewing machine provided by the present application. The principles and implementation manners of the present application are described by using specific examples in this paper. The above description of the embodiments is only used to help understand the method of the present application and its core idea. It should be pointed out that, for those skilled in the art, without departing from the principles of the present application, the present application can be improved and modified in several ways. These improvements and modifications also fall within the protection scope of the present application.

Claims

1. A thread tension regulating device, characterized by, The utility model relates to a line tension adjusting device, including: Support structure (1); Motor (2) is located one side of support structure (1); Clamping mechanism (3) is located the other side of support structure (1) with motor (2) is opposite, clamping mechanism (3) includes cam (31) and pass line wheel (32), cam (31) is connected with motor shaft (21) of motor (2), the outer edge of cam (31) is attached with pass line groove (321) of pass line wheel (32).

2. The thread tension regulating device of claim 1, wherein, Clamping mechanism (3) still includes elastic element (33), and elastic element (33) is used for connecting pass line wheel (32) with support structure (1), is used for providing reset force for pass line wheel (32).

3. The thread tension regulating device of claim 2, wherein, Clamping mechanism (3) still includes crank (34), and the rotating end of crank (34) is rotatably connected with support structure (1) through crank shaft (35), and the movable end is movably arranged in the first limiting hole (11) of support structure (1) through bearing (36) articulated limiting shaft (37).

4. The thread tension regulating device of claim 3, wherein The end of limiting shaft (37) away from support structure (1) is equipped with thread take-up spring (38), and pass line wheel (32) is arranged outside thread take-up spring (38), and pass line wheel (32) is equipped with the second limiting hole (322) for the thread take-up part of thread take-up spring (38) passes through.

5. The thread tension regulating device of claim 4, wherein, Elastic element (33) is tension spring, and the side of crank (34) close to support structure (1) is equipped with protrusion (341), and the side of support structure (1) close to crank (34) is equipped with hook spring column (12), and the both ends of tension spring are connected protrusion (341), hook spring column (12) through hooking structure respectively.

6. The thread tension regulating device according to any one of claims 1 to 5, wherein The outer edge of cam (31) is equipped with the line clamping ring (39) with elasticity.

7. The thread tension regulating device of claim 6, wherein, Pass line groove (321) is equipped with pressure sensor inside, for real-time detection the pressure of the outer edge of cam (31) or line clamping ring (39) to pass line groove (321).

8. The thread tension regulating device of claim 6, wherein, The outer contour of cam (31) is in the shape of archimedes spiral.

9. The thread tension regulating device of claim 8, wherein, Pass line groove (321) is arc slot.

10. A sewing machine characterized by comprising: The line tension adjusting device of any one of claims 1-9 is included.

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