Sewing machine and thread trimming driving mechanism thereof
By designing a thread-cutting driving mechanism in a sewing machine, using thread-cutting balls to contact and cooperate with the chute surface, the peak load torque of the motor during thread-cutting is reduced, and the problem of excessive motor performance in the prior art is solved, the working performance is improved and the service life is extended.
Patent Information
- Application Number
- CN202422151630.0
- Authority / Receiving Office
- CN · China
- Patent Type
- Utility models(China)
- Current Assignee / Owner
- Filing Date
- 2024-09-02
- Publication Date
- 2025-06-27
- Estimated Expiration
- 2034-09-02
AI Technical Summary
The existing sewing machine thread cutting mechanism generates a large peak load torque during the thread cutting process, resulting in excess motor performance and increasing production costs.
A wire-cutting driving mechanism is designed, including a driving motor, wire-cutting arm and wire-cutting driving member. Through contact and cooperation with the wire-cutting chute surface, the biting force between the moving knife and the fixed knife is reduced and the peak load torque is reduced.
It effectively reduces the peak load torque acting on the motor during the thread cutting process, improves the working performance of the motor, avoids heating, and extends the service life of the motor.
Smart Images
Figure CN223033630U_ABST
Abstract
Description
Technical Field
[0001] The utility model relates to the technical field of sewing machines, in particular to a sewing machine and a thread cutting driving mechanism thereof. Background Art
[0002] As Figure 1 shown, the existing thread cutting mechanism of a sewing machine includes a thread cutting shaft rotatably arranged in the sewing machine, a return spring 403 sleeved on the thread cutting shaft, a moving knife 501 in transmission connection with the thread cutting shaft, and a fixed knife 502 with a fixed position. One end of the thread cutting shaft is provided with a thread cutting crank 401, the thread cutting crank 401 is hinged to the first end of a thread cutting connecting rod 402, the second end of the thread cutting connecting rod 402 is hinged to a moving knife holder 503, and the moving knife 501 is fixed on the moving knife holder 503. One end of the return spring 403 is fixed in the sewing machine, and the other end is connected to the thread cutting crank 401. When the thread cutting shaft rotates, it can drive the moving knife 501 to rotate towards the fixed knife 502 and insert under the fixed knife 502, and the two are engaged to complete the thread cutting action. After the thread cutting is completed, the return spring 403 drives the thread cutting shaft to rotate and reset, and when thread cutting is not required, the return spring 403 also keeps the thread cutting shaft in its initial position.
[0003] During the process of the thread cutting mechanism performing the thread cutting action, the thread cutting crank 401 is subjected to a load torque M S , M S whose magnitude increases as the swing angle of the thread cutting crank 401 increases. Before the moving knife 501 and the fixed knife 502 enter the engagement stage, the two are separated from each other and there is no mutual acting force; when the moving knife 501 and the fixed knife 502 are engaged with each other, the moving knife holder 503 is subjected to a load torque M D , and the source of the load torque M D includes the extrusion friction force between the moving knife 501 and the fixed knife 502, the shearing resistance of the sewing thread fibers, etc. Therefore, during the thread cutting process, the moment of maximum thread cutting load is the moment when the moving knife 501 and the fixed knife 502 are about to end the engagement, at this time M S and M D both have the maximum value, and the combined load torque generated by the two is denoted as M SD .
[0004] Currently, the method of increasing the motor power is mostly adopted to cope with the load torque M SD during the thread cutting process, but this will cause the motor performance to be excessive and increase the production cost. Summary of the Utility Model
[0005] The purpose of the utility model is to provide a thread cutting driving mechanism, which can reduce the peak load torque acting on the motor during the thread cutting process.
[0006] The present utility model provides a thread cutting drive mechanism, which is arranged in a sewing machine. The sewing machine includes a thread cutting mechanism. The thread cutting mechanism includes a thread cutting shaft rotatably arranged in the sewing machine, a moving knife drivingly connected to the thread cutting shaft, and a fixed knife with a fixed position. The thread cutting drive mechanism includes a drive motor, a thread cutting arm rotated under the drive of the drive motor, and a thread cutting driving member arranged on the thread cutting shaft. A rotatable thread cutting ball is arranged on the thread cutting arm, a thread cutting driving arm is arranged on the thread cutting driving member, and a thread cutting chute surface for contact and cooperation with the thread cutting ball is arranged on the thread cutting driving arm. The thread cutting chute surface includes a thread cutting biting surface arranged at the end of the thread cutting driving arm. The output shaft rotation angle of the drive motor has independent feeding area and thread cutting area. When the output shaft operates in the feeding area, the thread cutting ball is separated from the thread cutting driving arm, and the thread cutting mechanism does not act. When the output shaft operates in the thread cutting area, the thread cutting ball is in contact and cooperation with the thread cutting chute surface, driving the moving knife to approach or move away from the fixed knife. When the moving knife and the fixed knife are about to end the biting, the thread cutting ball is in contact and cooperation with the thread cutting biting surface.
[0007] Preferably, one end of the thread cutting shaft is provided with a thread cutting crank, the thread cutting crank is hinged to the first end of a thread cutting connecting rod, and the second end of the thread cutting connecting rod is hinged to a moving knife holder. The moving knife is fixed on the moving knife holder.
[0008] Preferably, the moving knife is arc-shaped, a thread cutting bulge is arranged on its outer arc surface, a through hole is arranged in the thread cutting bulge, and the edge where the through hole intersects with the surface of the thread cutting bulge forms a moving knife thread cutting edge.
[0009] Preferably, one end of the fixed knife is provided with a flat fixed knife thread cutting edge.
[0010] Preferably, a reset arm is further arranged on the thread cutting driving member, and a forced reset surface for contact and cooperation with the thread cutting ball is arranged on the reset arm.
[0011] Preferably, the output shaft rotation angle of the drive motor further has a transition area distributed between the feeding area and the thread cutting area.
[0012] Preferably, the thread cutting drive mechanism is arranged below the sewing machine bottom plate.
[0013] The present utility model further provides a sewing machine, including the foregoing thread cutting drive mechanism.
[0014] The beneficial effect of the present utility model is that by optimizing the thread cutting drive structure, the drive motor has a smaller load torque during the process of realizing step-by-step thread cutting, has better working performance, can avoid the drive motor from heating, and prolongs the service life of the drive motor. Description of the Drawings
[0015] Figure 1 It is the force analysis diagram of the wire cutting mechanism during the wire cutting process;
[0016] Figure 2 It is the three-dimensional diagram of the wire cutting driving mechanism of the present utility model;
[0017] Figure 3 Schematic diagram of the working range of the driving motor;
[0018] Figure 4 It is the structural schematic diagram of the wire cutting driving part;
[0019] Figure 5 It is the schematic diagram of the relative position between the wire cutting ball and the wire cutting driving part at the moment of the maximum wire cutting load.
[0020] Description of component numbers:
[0021] 1 Driving motor
[0022] 11 Wire cutting area
[0023] 12 Transition area
[0024] 13 Feeding area
[0025] 2 Wire cutting arm
[0026] 31 Wire cutting ball
[0027] 32 Wire cutting driving part
[0028] 321 Wire cutting driving arm
[0029] 321a Wire cutting chute surface
[0030] 321b Wire cutting engaging surface
[0031] 322 Reset arm
[0032] 4 Wire cutting shaft
[0033] 41 / 401 Wire cutting crank
[0034] 42 / 402 Wire cutting connecting rod
[0035] 43 / 403 Reset spring
[0036] 51 / 501 Moving knife
[0037] 511 / 503 Moving knife holder
[0038] 52 / 502 Fixed knife Detailed implementation manners
[0039] The following further elaborates in detail on the specific implementation manners of the present utility model in conjunction with the accompanying drawings. These implementation manners are only used to illustrate the present utility model and do not limit the present utility model.
[0040] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "upper", "lower", "front", "rear", "left", "right", "top", "bottom", "inner", "outer", etc. is based on the orientation or positional relationship shown in the accompanying drawings. It is only for the convenience of describing the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation, and therefore should not be construed as a limitation to the present utility model.
[0041] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be directly connected, or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.
[0042] Figure 2 The following shows a perspective view of the thread cutting drive mechanism of the present utility model. In the following description, the accompanying drawings in Figure 2 are used as the reference basis for directions. In Figure 2 , the length direction of the thread cutting shaft 4 is defined as the left-right direction, and the thread cutting drive member 32 is located at the right end of the thread cutting shaft 4.
[0043] The present utility model provides a thread cutting drive mechanism and a sewing machine including the thread cutting drive mechanism.
[0044] As shown in Figure 2As shown, the sewing machine includes a thread trimming mechanism, which includes a thread trimming shaft 4 rotatably arranged in the sewing machine, a return spring 43 sleeved on the thread trimming shaft 4, a movable knife 51 connected to the thread trimming shaft 4, and a fixed fixed knife 52. Specifically, the thread trimming shaft 4 extends in the left and right directions, and a thread trimming crank 41 is provided at its left end. The thread trimming crank 41 is hinged to the first end of the thread trimming connecting rod 42, and the second end of the thread trimming connecting rod 42 is hinged to the movable knife frame 511, and the movable knife 51 is fixed on the movable knife frame 511. The movable knife 51 is arc-shaped, and a thread trimming bulge is provided on its outer arc surface. A through hole is provided in the thread trimming bulge, and the edge where the through hole intersects with the surface of the thread trimming bulge constitutes a thread trimming edge of the movable knife. A straight fixed knife thread trimming edge is provided at one end of the fixed knife 52. One end of the return spring 43 is fixed in the sewing machine, and the other end is connected to the thread trimming crank 41. When the thread trimming shaft 4 rotates, the movable knife 51 can be driven to rotate toward the fixed knife 52 and inserted under the fixed knife 52, so that the thread cutting edge of the movable knife and the thread cutting edge of the fixed knife are engaged with each other to complete the thread trimming action. After the thread trimming is completed, the return spring 43 drives the thread trimming shaft 4 to rotate and reset, and when the thread trimming is not needed, the return spring 43 also keeps the thread trimming shaft 4 at its initial position.
[0045] In order to reduce the peak load torque acting on the motor during the thread trimming process and make the motor load distribution more reasonable, such as Figure 2 As shown, the thread trimming drive mechanism provided by the utility model includes a driving motor 1, a thread trimming arm 2 rotating under the drive of the driving motor 1, and a thread trimming drive member 32 arranged on the thread trimming shaft 4. The thread trimming drive mechanism is arranged below the bottom plate of the sewing machine. The thread trimming arm 2 is provided with a rotatable thread trimming ball 31. Figure 4 As shown, the thread trimming driving member 32 is provided with a thread trimming driving arm 321 and a reset arm 322 extending in different directions. The outer peripheral surface of the thread trimming driving arm 321 has a thread trimming chute surface 321a for contacting and cooperating with the thread trimming ball 31, and the thread trimming chute surface 321a includes a thread trimming engaging surface 321b arranged at the end of the thread trimming driving arm 321. The reset arm 322 is staggered with the thread trimming driving arm 321 along the circumferential direction, and its outer peripheral surface has a forced reset surface for contacting and cooperating with the thread trimming ball 31.
[0046] like Figure 3 As shown, the output shaft rotation angle of the driving motor 1 has a feeding area 13 and a thread trimming area 11 which are independent of each other. The angles at both ends of the thread trimming area 11 are A1 and A2 respectively, and the angles at both ends of the feeding area 13 are A3 and A4 respectively. <A2<A3<A4。即,剪线区11的角度范围为A1~A2,送料区13的角度范围A3~A4。同时,驱动电机1的输出轴转角还具有分布在送料区13和剪线区11之间的过渡区12,过渡区12的角度范围为A2~A3。
[0047] When the sewing machine is sewing normally, the output shaft of the driving motor 1 rotates within the feeding area 13, and the thread cutting ball 31 is separated from the thread cutting driving arm 321 and does not transmit power. Therefore, the thread cutting mechanism does not perform the thread cutting action.
[0048] When thread cutting is required, the output shaft of the driving motor 1 reverses from the current angle in the feeding area 13 to the starting angle A2 of the thread cutting area 11, and then continuously reverses within the thread cutting area 11 to the ending angle A1 of the thread cutting area 11. As Figure 4 and Figure 5 shown, during the process of the output shaft rotating from A2 to A1, the thread cutting ball 31 is in contact and cooperation with the thread cutting chute surface 321a. The thread cutting arm 2 pushes the thread cutting driving member 32 to drive the thread cutting shaft 4 to rotate, and then through the thread cutting crank 41, the thread cutting connecting rod 42, and the moving knife holder 511, the moving knife 51 is driven to move, so that the moving knife 51 gradually approaches the fixed knife 52 and inserts below the fixed knife 52. When the moving knife 51 and the fixed knife 52 are about to end the engagement, the thread cutting ball 31 is in contact and cooperation with the thread cutting engagement surface 321b. The thread cutting engagement surface 321b has a specific angle, so that the acting force F of the thread cutting driving member 32 on the thread cutting arm 2 has a shorter force arm L (L ≤ 15 mm), thereby reducing the peak load torque M1 of the driving motor 1. After the thread cutting is completed, the output shaft of the driving motor 1 rotates forward to the current angle within the feeding area 13 before thread cutting. Under the action of the return spring 43, the thread cutting shaft 4 and the thread cutting driving member 32 rotate and reset, driving components such as the thread cutting crank 41, the thread cutting connecting rod 42, the moving knife holder 511, and the moving knife 51 to reset respectively. During the reset process, the thread cutting ball 31 is in contact and cooperation with the forced reset surface of the reset arm 322. The thread cutting ball 31 pushes the reset arm 322 to reset, and further drives the thread cutting driving member 32 and the thread cutting mechanism to be forcibly reset, reducing the risk that the moving knife 51 cannot be smoothly reset due to being stuck by lint. The setting of the reset arm 322 can help the moving knife 51 get out of the fault position and ensure the smooth execution of the next thread cutting action.
[0049] The above is only the preferred embodiment of the present invention. It should be noted that for those of ordinary skill in the art of this technology, without departing from the technical principle of the present invention, several improvements and replacements can still be made, and these improvements and replacements should also be regarded as the protection scope of the present invention.
Claims
1. A thread trimming drive mechanism, arranged in a sewing machine, the sewing machine comprising a thread trimming mechanism, the thread trimming mechanism comprising a thread trimming shaft rotatably arranged in the sewing machine, a movable knife drivingly connected to the thread trimming shaft, and a fixed knife at a fixed position, characterized in that: The thread trimming drive mechanism comprises a driving motor, a thread trimming arm rotating under the driving of the driving motor, and a thread trimming drive member arranged on the thread trimming shaft, the thread trimming arm is provided with a rotatable thread trimming ball, the thread trimming drive member is provided with a thread trimming drive arm, the thread trimming drive arm is provided with a thread trimming chute surface for contacting and cooperating with the thread trimming ball, and the thread trimming chute surface comprises a thread trimming bite surface arranged at the end of the thread trimming drive arm; The output shaft rotation angle of the driving motor has a feeding area and a thread cutting area which are independent of each other. When the output shaft operates in the feeding area, the thread trimming ball is separated from the thread trimming driving arm, and the thread trimming mechanism does not operate; When the output shaft rotates in the thread trimming area, the thread trimming ball contacts and cooperates with the thread trimming groove surface to drive the movable knife to approach or move away from the fixed knife; when the movable knife and the fixed knife are about to end the bite, the thread trimming ball contacts and cooperates with the thread trimming bite surface.
2. The thread trimming drive mechanism according to claim 1, characterized in that: A thread trimmer crank is provided at one end of the thread trimmer shaft. The thread trimmer crank is hinged to the first end of the thread trimmer connecting rod. The second end of the thread trimmer connecting rod is hinged to the moving knife frame. The moving knife is fixed on the moving knife frame.
3. The thread trimming drive mechanism according to claim 1, characterized in that: The movable knife is arc-shaped, and a thread cutting bulge is arranged on its outer arc surface. A through hole is arranged in the thread cutting bulge, and the edge where the through hole intersects with the surface of the thread cutting bulge constitutes the thread cutting edge of the movable knife.
4. The thread trimming drive mechanism according to claim 1, characterized in that: One end of the fixed knife is provided with a straight fixed knife thread cutting edge.
5. The thread trimming drive mechanism according to claim 1, characterized in that: The thread trimmer driving member is also provided with a reset arm, and the reset arm is provided with a forced reset surface for contacting and cooperating with the thread trimmer ball.
6. The thread trimming drive mechanism according to claim 1, characterized in that: The output shaft rotation angle of the driving motor also has a transition zone distributed between the feeding zone and the thread cutting zone.
7. The thread trimming drive mechanism according to claim 1, characterized in that: The thread trimming driving mechanism is arranged below the bottom plate of the sewing machine.
8. A sewing machine, characterized in that: It comprises the thread cutting drive mechanism as claimed in any one of claims 1 to 7.