Sewing machine and feeding driving mechanism thereof

Abstract

The utility model provides a sewing machine and feed driving mechanism thereof, sewing machine comprises a feed dog frame, feed dog fixed on the feed dog frame, feed mechanism connected with the first end of the feed dog frame and a needle plate, feed driving mechanism comprises a driving motor and a feed arm which rotates under the driving of the driving motor, the feed dog is fixed on the feed dog frame, the feed mechanism is connected with the first end of the feed dog frame, and the needle plate is fixed on the feed dog frame. The feeding arm is connected with the feeding mechanism through a feeding connecting rod; the corner of the output shaft of the driving motor is provided with a feeding area, and when the output shaft operates in the feeding area, the feeding arm drives the feeding teeth to reciprocate back and forth; when the feeding teeth are about to come out of the needle plate, the included angle between the axis of the feeding arm and the axis of the feeding connecting rod is smaller than or equal to 25 degrees. The utility model further provides a sewing machine which comprises the feeding driving mechanism. The feeding driving structure has the advantages that by optimizing the feeding driving structure, the driving motor has small load torque in the feeding process, the working performance is better, heating of the driving motor can be avoided, and the service life of the driving motor is prolonged.

Description

Technical Field

[0001] The utility model relates to the technical field of sewing machines, in particular to a sewing machine and a feeding drive mechanism thereof. Background Art

[0002] As Figure 1 shown, a sewing machine includes a feeding mechanism, a lifting tooth mechanism, a tooth carrier 500, and a feed dog 501 fixed on the tooth carrier 500. When the sewing machine works, the feeding mechanism drives the tooth carrier 500 and the feed dog 501 to perform reciprocating motion back and forth, and the lifting tooth mechanism 7 drives the tooth carrier 500 and the feed dog 501 to perform reciprocating motion up and down. Finally, the feed dog 501 performs a compound motion with a trajectory similar to an ellipse as Figure 2 shown, driving the sewing material 200 to move forward to complete the feeding action.

[0003] As Figure 1 and Figure 2 shown, during the process of the feed dog 501 transporting the sewing material 200 (by default, there is no relative movement between the feed dog 501 and the sewing material 200), the feed dog 501 emerges from the upper surface of the needle plate 100, and the presser foot 300 presses the sewing material 200 under the action of the spring 400 and generates a downward positive pressure F N (F N (the numerical change amount caused by the change in tooth height is very small, and the numerical change amount ≤ 5%). Due to the existence of the positive pressure F N , the feed dog 501 is subjected to a frictional force f in the direction opposite to its feeding direction, and the value of the frictional force f is basically constant during the stable feeding process. At the same time, due to the high-speed operation of the machine, the feeding execution components such as the tooth carrier 500 and the feed dog 501 are also subjected to their own inertial force F m in the front and back directions in addition to the frictional force f. When the feed dog 501 is about to sink into the needle plate 100 or about to emerge from the upper surface of the needle plate 100, the speed of the feed dog 501 is the smallest and the acceleration is the largest. Therefore, the inertial force F m has the maximum value at the two limit points in the front and back directions of the movement trajectory of the feed dog. When the feed dog 501 runs in the first quadrant (i.e., during the process of the feed dog 501 emerging from the needle plate 100 to reaching the highest point), the directions of f and F m are the same, and the overall load of the feeding execution component is f + F m ; when the feed dog 501 runs in the second quadrant (i.e., during the process of the feed dog 501 falling from the highest point into the needle plate 100), the directions of f and F m are opposite, and the overall load of the feeding execution component is f - F m . It can be judged that within a feeding cycle, the moment of the maximum feeding load is the moment t1 when the feed dog 501 is about to emerge from the upper surface of the needle plate 100, and at this time, the load of the feeding execution component is f + F m .

[0004] Currently, the method of increasing the motor power is mostly adopted to cope with the load torque during the feeding process, but this will cause the overcapacity of the motor performance and increase the production cost. Summary of the Invention

[0005] The purpose of the present utility model is to provide a feeding drive mechanism, which can reduce the peak load torque acting on the motor during the feeding process.

[0006] The present utility model provides a feeding drive mechanism, which is arranged in a sewing machine. The sewing machine includes a tooth carrier, a feed dog fixed on the tooth carrier, a feeding mechanism connected to the first end of the tooth carrier, and a needle plate allowing the feed dog to protrude. The feeding drive mechanism includes a drive motor and a feeding arm rotated under the drive of the drive motor. The feeding arm is connected to the feeding mechanism through a feeding connecting rod. The output shaft rotation angle of the drive motor has a feeding area. When the output shaft operates in the feeding area, the feeding arm drives the feed dog to perform a reciprocating motion back and forth. When the feed dog is about to protrude from the needle plate, the included angle between the axis of the feeding arm and the axis of the feeding connecting rod is less than or equal to 25°.

[0007] Preferably, the output shaft rotation angle of the drive motor further has a thread trimming area, and the thread trimming area is independent of the feeding area. When the output shaft operates in the thread trimming area, the feeding arm and the feeding connecting rod are collinear, and the feed dog stops feeding.

[0008] Preferably, the output shaft rotation angle of the drive motor further has a transition area distributed between the feeding area and the thread trimming area.

[0009] Preferably, the feeding mechanism includes a feeding shaft rotatably arranged in the sewing machine and a tooth carrier seat fixed at the first end of the feeding shaft. The tooth carrier seat is hinged to the first end of the tooth carrier.

[0010] Preferably, the feeding arm is hinged to the first end of the feeding connecting rod, the second end of the feeding connecting rod is hinged to the first end of the feeding crank, and the second end of the feeding crank is hinged to the second end of the feeding shaft.

[0011] Preferably, the feeding drive mechanism is arranged below the needle plate.

[0012] The present utility model further provides a sewing machine, including the foregoing feeding drive mechanism.

[0013] Preferably, a tooth lifting mechanism is further included. The tooth lifting mechanism includes a tooth lifting shaft rotatably arranged in the sewing machine, a tooth lifting fork-shaped crank fixed at one end of the tooth lifting shaft, and a tooth lifting slider slidably assembled in the opening of the tooth lifting fork-shaped crank. The tooth lifting slider is hinged to the second end of the tooth carrier.

[0014] The beneficial effect of the present utility model is that by optimizing the feeding drive structure, the driving motor has a smaller load torque during the realization of electronic feeding, with better working performance, and can avoid the heating of the driving motor and extend the service life of the driving motor. Description of the Drawings

[0015] Figure 1 is the force analysis diagram of the feed dog during feeding;

[0016] Figure 2 is the schematic diagram of the frictional force and inertial force received by the feed dog within one feeding cycle;

[0017] Figure 3 is the perspective view of the feeding drive mechanism of the present utility model;

[0018] Figure 4 is the schematic diagram of the working range of the driving motor;

[0019] Figure 5 is the schematic diagram of the relative position of the feeding connecting rod and the feeding arm at the moment of maximum feeding load.

[0020] Explanation of Component Labels:

[0021] 1 Driving motor

[0022] 11 Thread cutting area

[0023] 12 Transition area

[0024] 13 Feeding area

[0025] 2 Feeding arm

[0026] 31 Feeding connecting rod

[0027] 32 Feeding crank

[0028] 4 Feeding shaft

[0029] 41 Tooth carrier base

[0030] 5 / 500 Tooth carrier

[0031] 51 / 501 Feed dog

[0032] 6 Thread cutting mechanism

[0033] 7 Tooth lifting mechanism

[0034] 100 Needle plate

[0035] 200 Sewing material

[0036] 300 Presser foot

[0037] 400 Spring Specific embodiments

[0038] The following further details the specific embodiments of the present utility model in conjunction with the accompanying drawings. These embodiments are only for illustrating the present utility model and are not intended to limit the present utility model.

[0039] 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.

[0040] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", "connection" 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.

[0041] Figure 3 The following shows a perspective view of the feeding drive mechanism of the present utility model. In the following description, the accompanying drawings in Figure 3 are used as the reference basis for directions. In Figure 3 , the length direction of the feeding shaft 4 is defined as the left - right direction, and the driving motor 1 is located on the right side of the tooth carrier 5; the setting direction of the tooth carrier 5 is defined as the front - rear direction, and the tooth carrier base 41 is located on the front side of the lifting tooth mechanism 7; the direction perpendicular to the left - right direction and the front - rear direction is defined as the up - down direction.

[0042] The present utility model provides a feeding drive mechanism and a sewing machine including the feeding drive mechanism.

[0043] As Figure 3 shown, the sewing machine includes a thread cutting mechanism 6, a tooth carrier 5, a feeding tooth 51 fixed on the tooth carrier 5, a feeding mechanism connected to the front end (i.e., the first end) of the tooth carrier 5, a lifting tooth mechanism 7 connected to the rear end (i.e., the second end) of the tooth carrier 5, and a needle plate 100 through which the feeding tooth 51 can protrude.

[0044] Among them, the sewing material 200 is placed on the needle plate 100; the feeding mechanism includes a feeding shaft 4 rotatably arranged in the sewing machine and a tooth rest base 41 fixed to the left end of the feeding shaft 4, and the tooth rest base 41 is hinged to the front end of the tooth rest 5; the lifting tooth mechanism 7 includes a lifting tooth shaft rotatably arranged in the sewing machine, a lifting tooth fork-shaped crank fixed to the left end of the lifting tooth shaft, and a lifting tooth slider slidably assembled in the opening of the lifting tooth fork-shaped crank. The lifting tooth slider is hinged to the rear end of the tooth rest 5, and the lifting tooth shaft extends in the left-right direction. When the sewing machine works, the feeding shaft 4 and the lifting tooth shaft rotate. The feeding mechanism drives the tooth rest 5 and the feeding tooth 51 to perform reciprocating motion back and forth, and the lifting tooth mechanism 7 drives the tooth rest 5 and the feeding tooth 51 to perform reciprocating motion up and down. Finally, the feeding tooth 51 performs a compound motion with a trajectory similar to an ellipse as shown in Figure 2 shown, driving the sewing material 200 to move forward to complete the feeding action.

[0045] To reduce the peak load torque acting on the motor during the feeding process and make the motor load distribution more reasonable, as shown in Figure 3 shown, the feeding drive mechanism provided by the present invention includes a drive motor 1 and a feeding arm 2 that rotates under the drive of the drive motor 1. The feeding drive mechanism is arranged below the needle plate 100. The feeding arm 2 is connected to the feeding mechanism through a feeding connecting rod 31. Specifically, the feeding arm 2 is hinged to the first end of the feeding connecting rod 31, the second end of the feeding connecting rod 31 is hinged to the first end of the feeding crank 32, and the second end of the feeding crank 32 is hinged to the right end (i.e., the second end) of the feeding shaft 4.

[0046] As shown in Figure 4 shown, the output shaft rotation angle of the drive motor 1 has an independent feeding area 13 and a thread cutting area 11. The two ends of the thread cutting area 11 have angles A1 and A2 respectively, and the two ends of the feeding area 13 have angles A3 and A4 respectively. Along the forward rotation direction of the drive motor 1, A1 < A2 < A3 < A4. That is, the angle range of the thread cutting area 11 is A1~A2, and the angle range of the feeding area 13 is A3~A4. At the same time, the output shaft rotation angle of the drive motor 1 also has a transition area 12 distributed between the feeding area 13 and the thread cutting area 11, and the angle range of the transition area 12 is A2~A3.

[0047] When the sewing machine is sewing normally, the output shaft of the drive motor 1 operates within the feeding area 13, and the thread cutting mechanism 6 does not perform the thread cutting action. The feeding arm 2 drives the feeding tooth 51 to perform reciprocating motion back and forth through the feeding connecting rod 31 and the feeding mechanism, and the feeding tooth 51 feeds normally. As shown in Figure 5 shown, when the feeding tooth 51 is about to emerge from the needle plate 100, the included angle θ between the axis of the feeding arm 2 and the axis of the feeding connecting rod 31 is less than or equal to 25°. The smaller included angle θ makes the acting force F of the feeding connecting rod 31 on the feeding arm 2 have a shorter force arm L (L ≤ 15 mm), thereby reducing the peak load torque M1 of the drive motor 1.

[0048] When wire cutting is required, the output shaft of the driving motor 1 reverses from the current angle of the feeding area 13 to the wire cutting area 11, and the wire cutting mechanism 6 performs the moving wire cutting action. When the output shaft of the driving motor 1 rotates within the wire cutting area 11, the feeding arm 2 and the feeding connecting rod 31 are collinear, and the feeding crank 32 remains basically stationary. Therefore, the displacement of the feeding tooth 51 in the front-back direction is very small, and the feeding action is not performed.

[0049] The above are only the preferred embodiments 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 substitutions can be made, and these improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A feeding drive mechanism, arranged in a sewing machine, the sewing machine comprising a tooth frame, a feed tooth fixed on the tooth frame, a feeding mechanism connected to a first end of the tooth frame, and a needle plate allowing the feed tooth to emerge, characterized in that: The feeding drive mechanism comprises a driving motor and a feeding arm that rotates under the drive of the driving motor, and the feeding arm is connected to the feeding mechanism through a feeding connecting rod; The output shaft angle of the driving motor has a feeding area. When the output shaft rotates in the feeding area, the feeding arm drives the feeding dog to reciprocate back and forth. When the feeding dog is about to emerge from the needle plate, the angle between the axis of the feeding arm and the axis of the feeding connecting rod is less than or equal to 25°.

2. The feeding drive mechanism according to claim 1, characterized in that: The output shaft rotation angle of the driving motor also has a thread trimming area, and the thread trimming area is independent of the feeding area; when the output shaft runs in the thread trimming area, the feeding arm and the feeding connecting rod are in line, and the feeding dog stops feeding.

3. The feeding drive mechanism according to claim 2, 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.

4. The feeding drive mechanism according to claim 1, characterized in that: The feeding mechanism comprises a feeding shaft rotatably arranged in the sewing machine and a tooth frame seat fixed to the first end of the feeding shaft, and the tooth frame seat is hinged to the first end of the tooth frame.

5. The feeding drive mechanism according to claim 4, characterized in that: The feeding arm is hinged to the first end of the feeding connecting rod, the second end of the feeding connecting rod is hinged to the first end of the feeding crank, and the second end of the feeding crank is hinged to the second end of the feeding shaft.

6. The feeding drive mechanism according to claim 1, characterized in that: The feeding drive mechanism is arranged below the needle plate.

7. A sewing machine, characterized in that: It comprises a feeding drive mechanism as described in any one of claims 1-6.

8. The sewing machine according to claim 7, characterized in that It also includes a tooth lifting mechanism, which includes a tooth lifting shaft rotatably arranged in the sewing machine, a tooth lifting fork crank fixed at one end of the tooth lifting shaft, and a tooth lifting slider slidably assembled in the opening of the tooth lifting fork crank, and the tooth lifting slider is hinged to the second end of the tooth frame.

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