Feeding mechanism capable of switching differential ratio and sewing machine

Abstract

The utility model discloses a feeding mechanism capable of switching differential ratio and a sewing machine in the technical field of sewing machines, which comprise a bottom plate, a main feeding motor, a differential feeding motor, a feed lifting shaft, a main feeding shaft and a differential feeding shaft, and the main feeding motor, the differential feeding motor, the feed lifting shaft, the main feeding shaft and the differential feeding shaft are mounted below the bottom plate. A main feeding tooth frame is connected between the front end of the main feeding shaft and the feed lifting tooth shaft, a main transmission four-connecting-rod assembly is connected between the rear end of the main feeding shaft and the main feeding motor, a differential feeding tooth frame is connected between the front end of the differential feeding shaft and the feed lifting tooth shaft, and a differential transmission four-connecting-rod assembly is connected between the rear end of the differential feeding shaft and the differential feeding motor. By controlling the swing amplitude of the swing output shaft of the main feeding motor and the swing amplitude of the swing output shaft of the differential feeding motor, not only can the differential ratio be switched and different sewing modes be realized, but also the structure is simple, the universality is high, the working efficiency is improved, the product competitiveness is improved, and the sewing machine is suitable for batch popularization.

Description

Technical Field

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

[0002] The down differential sewing machine has the advantages of anti-wrinkle, shrinkage and suitable for sewing cuffs. It is widely used in sewing some special fabrics and processes.

[0003] At present, most of the mainstream differential feed flat-bed sewing machines on the market are special models. Each model not only needs to be redesigned, but also has complex structure, poor parts versatility, high production cost, and large technical limitations, making it difficult to promote and apply in large quantities.

[0004] Therefore, how to improve the versatility of the lower differential sewing machine has become a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0005] In view of this, the purpose of the utility model is to provide a feeding mechanism capable of switching differential ratios, so as to solve the technical problem of poor versatility of existing lower differential sewing machines.

[0006] The technical solution adopted by the utility model is: a feeding mechanism capable of switching differential ratio, comprising:

[0007] Base plate;

[0008] A tooth-lifting shaft, which is rotatably mounted below the bottom plate, and a main tooth-lifting fork and a differential tooth-lifting fork are mounted on the front end of the tooth-lifting shaft;

[0009] A main feeding shaft, which is rotatably mounted below the bottom plate, is parallel to the tooth-lifting shaft, a main feeding front crank is mounted at the front end of the main feeding shaft, and a main feeding tooth frame is connected between the main feeding front crank and the main tooth-lifting fork;

[0010] A main feeding motor, the main feeding motor is installed below the bottom plate, and a main transmission four-link assembly for driving the main feeding shaft to swing back and forth is connected between the swing output shaft of the main feeding motor and the rear end of the main feeding shaft;

[0011] A differential feeding shaft, wherein the differential feeding shaft is rotatably coaxially arranged in the inner cavity of the main feeding shaft, a differential feeding front crank is installed at the front end of the differential feeding shaft, and a differential feeding tooth frame is connected between the differential feeding front crank and the differential tooth lifting fork;

[0012] A differential feeding motor is installed below the bottom plate, and a differential transmission four-link assembly for driving the differential feeding shaft to swing back and forth is connected between the swing output shaft of the differential feeding motor and the rear end of the differential feeding shaft.

[0013] Preferably, it also includes an electric control module, which is electrically connected to the main feeding motor and the differential feeding motor respectively and can adjust the reciprocating swing angles of the main feeding shaft and the differential feeding shaft.

[0014] Preferably, the rotatable sleeve on the main feed shaft is provided with a front sleeve and a rear sleeve, and the front sleeve and the rear sleeve are fixedly installed in the mounting holes below the base plate, a retaining ring is provided on one axial side of the front sleeve, and the retaining ring is fixedly connected to the main feed shaft, and an external retaining spring is provided on the other axial end of the front sleeve, and the external retaining spring is fixedly connected to the main feed shaft.

[0015] Preferably, the front end of the differential feed shaft extends axially to the outside of the main feed shaft and is fixedly connected to the differential feed front crank, the front end of the differential feed shaft is fixedly installed with an internal retaining spring, and the internal retaining spring abuts against the front end surface of the main feed shaft, and the rear end of the differential feed shaft is fixedly installed with a thrust ball bearing, and the thrust ball bearing abuts against the rear end surface of the main feed shaft.

[0016] Preferably, the main transmission four-link assembly includes a main drive crank, a main feed connecting rod and a main feed rear crank, the main drive crank is fixedly connected to the swing output shaft of the main feed motor, the main feed rear crank is fixedly connected to the rear end of the main feed shaft, one end of the main feed connecting rod is hinged to the main drive crank, and the other end of the main feed connecting rod is hinged to the main feed rear crank.

[0017] Preferably, the differential transmission four-bar assembly includes a differential drive crank, a differential feeding connecting rod and a differential feeding rear crank, the differential drive crank is fixedly connected to the swing output shaft of the differential feeding motor, the differential feeding rear crank is fixedly connected to the rear end of the differential feeding shaft, and a thrust ball bearing is arranged between the rear end surface of the differential feeding rear crank and the main feeding shaft, one end of the differential feeding connecting rod is hinged to the differential drive crank, and the other end of the differential feeding connecting rod is hinged to the differential feeding rear crank.

[0018] Preferably, the middle portion of the differential drive crank is fixedly connected to the swing output shaft of the differential feeding motor, the upper swing end of the differential drive crank is hinged to the differential feeding connecting rod, and the lower swing end of the differential drive crank is transmission-connected to the thread cutting drive assembly.

[0019] Preferably, a first motor bracket and a second motor bracket are detachably installed under the bottom plate, the main feeding motor is fixedly connected to the first motor bracket, and the differential feeding motor is fixedly connected to the second motor bracket.

[0020] The second object of the present utility model is to provide a sewing machine, which comprises the above-mentioned feeding mechanism capable of switching the differential ratio.

[0021] Beneficial effects of the utility model:

[0022] In the utility model, a differential feed shaft is rotatably and coaxially arranged in the inner cavity of a main feed shaft. A main feed tooth bracket is connected between the front end of the main feed shaft and a lifting tooth shaft. A main transmission four-link assembly is connected between the rear end of the main feed shaft and a main feed motor. A differential feed tooth bracket is connected between the front end of the differential feed shaft and the lifting tooth shaft. A differential transmission four-link assembly is connected between the rear end of the differential feed shaft and a differential feed motor. By controlling the swing amplitude of the swing output shafts of the main feed motor and the differential feed motor, not only can the differential ratio be switched to achieve different sewing modes, but also the structure is simple and the universality is strong, greatly enhancing the adaptability of the sewing machine to different fabrics and working conditions, simplifying the adjustment operation, improving the working efficiency, enhancing the product competitiveness, and being suitable for batch promotion. Description of the Drawings

[0023] Figure 1 is a schematic structural diagram of a feeding mechanism capable of switching the differential ratio of the utility model;

[0024] Figure 2 is a first perspective structural diagram of a feeding mechanism capable of switching the differential ratio after removing the bottom plate;

[0025] Figure 3 is a second perspective structural diagram of a feeding mechanism capable of switching the differential ratio after removing the bottom plate;

[0026] Figure 4 is a partial schematic diagram of a feeding mechanism capable of switching the differential ratio of the utility model

[0027] Figure 5 is Figure 4 the A-A view in

[0028] Figure 6 is a connection schematic diagram of a differential feed motor and a thread cutting drive assembly;

[0029] Figure 7 is a schematic diagram of different cloth feeding trajectories of a main feed tooth and a differential feed tooth.

[0030] Explanation of the reference numerals in the drawings:

[0031] 1. Bottom plate; 2. Lifting tooth shaft; 3. Main lifting tooth fork; 4. Differential lifting tooth fork; 5. Main feeding shaft; 6. Main feeding front crank; 7. Main feeding tooth frame; 8. Main feeding motor; 9. Main transmission four-bar linkage assembly; 10. Differential feeding shaft; 11. Differential feeding front crank; 12. Differential feeding tooth frame; 13. Differential feeding motor; 14. Differential transmission four-bar linkage assembly; 15. Front shaft sleeve; 16. Rear shaft sleeve; 17. Retaining ring; 18. External circlip; 19. Internal circlip; 20. Thrust ball bearing; 21. Main drive crank; 22. Main feeding connecting rod; 23. Main feeding rear crank; 24. Differential drive crank; 25. Differential feeding connecting rod; 26. Differential feeding rear crank; 27. Thread cutting drive assembly; 28. First motor bracket; 29. Second motor bracket; 30. First lifting tooth slider; 31. Second lifting tooth slider; 32. Main feeding tooth; 33. Differential feeding tooth; 34. Thread cutting slider; 35. Thread cutting fork-shaped crank; 36. Thread cutting shaft. Specific embodiments

[0032] The following further elaborates on the specific embodiments of the present utility model in conjunction with the accompanying drawings. These embodiments are only used to illustrate the present utility model and are not intended to limit the present utility model.

[0033] In the description of the present utility model, it should be noted that the orientation or positional relationship indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "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 thus cannot be construed as a limitation of the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0034] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "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 a mechanical connection or an electrical 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.

[0035] In addition, in the description of the present utility model, unless otherwise stated, the meaning of "a plurality of" is two or more.

[0036] Embodiment, such as Figures 1-7As shown in the figure, a feeding mechanism capable of switching the differential ratio includes: a bottom plate 1, a lifting shaft 2, a main feeding shaft 5, a main feeding motor 8, a differential feeding shaft 10, and a differential feeding motor 13. Among them, the bottom plate 1 is horizontally arranged in the front-rear direction. The lifting shaft 2 is rotatably installed below the bottom plate 1, and a main lifting fork 3 and a differential lifting fork 4 are installed at the front end of the lifting shaft 2. The main feeding shaft 5 is rotatably installed below the bottom plate 1 and is parallel to the lifting shaft 2. A main front feeding crank 6 is installed at the front end of the main feeding shaft 5, and a main feeding tooth frame 7 is connected between the main front feeding crank 6 and the main lifting fork 3. The main feeding motor 8 is installed below the bottom plate 1, and a main transmission four-link assembly 9 for driving the main feeding shaft 5 to swing reciprocally is connected between the swing output shaft of the main feeding motor 8 and the rear end of the main feeding shaft 5. The differential feeding shaft 10 is rotatably and coaxially arranged in the inner cavity of the main feeding shaft 5. The front end of the differential feeding shaft 10 axially extends and a differential front feeding crank 11 is installed, and a differential feeding tooth frame 12 is connected between the differential front feeding crank 11 and the differential lifting fork 4. The differential feeding motor 13 is installed below the bottom plate 1, and a differential transmission four-link assembly 14 for driving the differential feeding shaft 10 to swing reciprocally is connected between the swing output shaft of the differential feeding motor 13 and the rear end of the differential feeding shaft 10.

[0037] In this application, the differential feeding shaft 10 is rotatably and coaxially arranged in the inner cavity of the main feeding shaft 5. A main feeding tooth frame 7 is connected between the front end of the main feeding shaft 5 and the lifting shaft 2. A main transmission four-link assembly 9 is connected between the rear end of the main feeding shaft 5 and the main feeding motor 8. A differential feeding tooth frame 12 is connected between the front end of the differential feeding shaft 10 and the lifting shaft 2. A differential transmission four-link assembly 14 is connected between the rear end of the differential feeding shaft 10 and the differential feeding motor 13. By controlling the swing amplitude of the swing output shafts of the main feeding motor 8 and the differential feeding motor 13, not only can the differential ratio be switched to achieve different sewing modes, but also the structure is simple and the versatility is strong, greatly enhancing the adaptability of the sewing machine to different fabrics and working conditions. It also simplifies the adjustment operation, improves the work efficiency, enhances the product competitiveness, and is suitable for batch promotion.

[0038] It should be noted that: the front-rear direction in this application refers to Figure 1 the direction of the double arrow in

[0039] Specific embodiment 1, as Figures 1-7 shown, a feeding mechanism capable of switching the differential ratio includes: a bottom plate 1, a lifting shaft 2, a main feeding shaft 5, a main feeding motor 8, a differential feeding shaft 10, a differential feeding motor 13, a main feeding tooth frame 7, and a differential feeding tooth frame 12. The bottom plate 1 is horizontally arranged in the front-rear direction. The lifting shaft 2 is horizontally installed below the bottom plate 1 in the front-rear direction and can rotate circumferentially around its own axis. A main lifting fork 3 and a differential lifting fork 4 are installed at the front end of the lifting shaft 2.

[0040] The main feeding shaft 5 is horizontally installed below the bottom plate 1 in the front-rear direction. The main feeding shaft 5 is parallel to the lifting tooth shaft 2, and the main feeding shaft 5 can rotate circumferentially around its own axis. A main feeding front crank 6 is fixedly installed at the front end of the main feeding shaft 5. The main feeding tooth bracket 7 is arranged between the main feeding shaft 5 and the lifting tooth shaft 2, and one end of the main feeding tooth bracket 7 is connected to the first lifting tooth slider 30. The first lifting tooth slider 30 is slidably connected in the chute of the main lifting tooth fork 3. The other end of the main feeding tooth bracket 7 is hinged to the main feeding front crank 6. The main feeding tooth 32 is installed above the main feeding tooth bracket 7, and the main feeding tooth 32 is fixedly connected to the middle part of the main feeding tooth bracket 7.

[0041] The main feeding motor 8 is arranged below the bottom plate 1. A first motor bracket 28 is detachably installed below the bottom plate 1. The main feeding motor 8 is fixedly connected to the first motor bracket 28, and the swing output shaft of the main feeding motor 8 is arranged in the front-rear direction. A main transmission four-link mechanism 9 for driving the main feeding shaft 5 to swing reciprocally is connected between the end of the swing output shaft of the main feeding motor 8 and the rear end of the main feeding shaft 5.

[0042] Specifically, the main transmission four-link mechanism 9 includes a main driving crank 21, a main feeding connecting rod 22 and a main feeding rear crank 23. The connecting end (the bottom end in the figure) of the main driving crank 21 is fixedly connected to the end of the swing output shaft of the main feeding motor 8. The connecting end (the top end in the figure) of the main feeding rear crank 23 is fixedly connected to the rear end of the main feeding shaft 5. One end of the main feeding connecting rod 22 is hinged to the swing end (the top end in the figure) of the main driving crank 21. The other end of the main feeding connecting rod 22 is hinged to the swing end (the bottom end in the figure) of the main feeding rear crank 23, so as to drive the main feeding shaft 5 to swing reciprocally through the transmission of the crank-link mechanism.

[0043] The inside of the main feeding shaft 5 is hollow. The differential feeding shaft 10 is rotatably installed in the inner cavity of the main feeding shaft 5, and the differential feeding shaft 10 is coaxial with the main feeding shaft 5. The two ends of the differential feeding shaft 10 axially extend to the outside of the main feeding shaft 5, and a differential feeding front crank 11 is fixedly installed at the front end of the differential feeding shaft 10. The differential feeding tooth bracket 12 is arranged between the differential feeding shaft 10 and the lifting tooth shaft 2, and one end of the differential feeding tooth bracket 12 is connected to the second lifting tooth slider 31. The second lifting tooth slider 31 is slidably connected in the chute of the differential lifting tooth fork 4. The other end of the differential feeding tooth bracket 12 is hinged to the differential feeding front crank 11. The differential feeding tooth 33 is installed above the differential feeding tooth bracket 12, and the differential feeding tooth 33 is fixedly connected to the middle part of the differential feeding tooth bracket 12.

[0044] The differential feeding motor 13 is arranged below the bottom plate 1. A second motor bracket 29 is detachably installed below the bottom plate 1. The differential feeding motor 13 is fixedly connected to the second motor bracket 29. The swing output shaft of the differential feeding motor 13 is arranged in the front-rear direction. A differential transmission four-bar linkage assembly 14 for driving the differential feeding shaft 10 to swing reciprocally is connected between the swing output shaft of the differential feeding motor 13 and the rear end of the differential feeding shaft 10.

[0045] Specifically, the differential transmission four-bar linkage assembly 14 includes a differential driving crank 24, a differential feeding connecting rod 25 and a differential feeding rear crank 26. The connecting end (the top end in the figure) of the differential driving crank 24 is fixedly connected to the end of the swing output shaft of the differential feeding motor 13. The connecting end (the top end in the figure) of the differential feeding rear crank 26 is fixedly connected to the rear end of the differential feeding shaft 10. One end of the differential feeding connecting rod 25 is hinged to the swing end (the bottom end in the figure) of the differential driving crank 24. The other end of the differential feeding connecting rod 25 is hinged to the swing end (the bottom end in the figure) of the differential feeding rear crank 26. So as to drive the differential feeding shaft 10 to swing reciprocally through the transmission of the crank and connecting rod mechanism by the differential feeding motor 13.

[0046] In other embodiments, the feeding mechanism further includes an electronic control module (not shown in the figure). The electronic control module is electrically connected to the main feeding motor 8 by electrical signals. And the electronic control module can control the swing amplitude of the swing output shaft of the main feeding motor 8, that is, the electronic control module can adjust the reciprocating swing angle of the main feeding shaft 5 by controlling the main feeding motor 8. The electronic control module is electrically connected to the differential feeding motor 13 by electrical signals. And the electronic control module can control the swing amplitude of the swing output shaft of the differential feeding motor 13, that is, the electronic control module can adjust the reciprocating swing angle of the differential feeding shaft 10 by controlling the differential feeding motor 13, so as to realize the automatic adjustment of the differential ratio.

[0047] In other embodiments, the coaxial setting of the main feeding shaft 5 and the differential feeding shaft 10 is realized as follows: A front shaft sleeve 15 and a rear shaft sleeve 16 are rotatably sleeved on the middle part of the main feeding shaft 5. And the front shaft sleeve 15 and the rear shaft sleeve 16 are fixedly installed in the installation holes below the bottom plate 1 by an interference fit method. A retaining ring 17 is arranged on one axial side of the front shaft sleeve 15. The retaining ring 17 is sleeved on the main feeding shaft 5 and fixedly connected to the main feeding shaft 5. And one end face of the retaining ring 17 is attached to the rear end face of the front shaft sleeve 15. An external circlip 18 is arranged on the other axial end of the front shaft sleeve 15. The external circlip 18 is sleeved on the main feeding shaft 5. And the inner ring of the external circlip 18 is fixedly connected to the main feeding shaft 5. One end face of the external circlip 18 is attached to the front end face of the front shaft sleeve 15, which is used for axially limiting the main feeding shaft 5.

[0048] Both ends of the differential feed shaft 10 extend axially to the outside of the main feed shaft 5, and an inner retaining spring 19 is sleeved on the front end of the differential feed shaft 10. The inner ring of the inner retaining spring 19 is fixedly connected to the differential feed shaft 10, and the end face of the inner retaining spring 19 is in contact with the front end face of the main feed shaft 5; a thrust ball bearing 20 and a differential feeding rear crank 26 are fixedly installed at the rear end of the differential feed shaft 10, one end face of the thrust ball bearing 20 is in contact with the rear end face of the main feed shaft 5, and the other end face of the thrust ball bearing 20 is in contact with the end face of the differential feeding rear crank 26, which is used to axially limit the differential feed shaft 10.

[0049] In other embodiments, the middle part of the differential drive crank 24 is fixedly connected to the end of the swing output shaft of the differential feeding motor 13, and the differential drive crank 24 has an upper swing end and a lower swing end arranged one above and one below, the upper swing end of the differential drive crank 24 is hinged to the differential feeding connecting rod 25, and the lower swing end of the differential drive crank 24 is transmission connected to the thread cutting drive assembly 27, so that the differential feeding motor 13 can drive the thread cutting action, realizing one-to-two motors, thereby simplifying the sewing machine structure and reducing costs.

[0050] It should be noted that the transmission connection between the lower swing end of the differential drive crank 24 and the wire cutting drive assembly 27 is the existing technology. For example, the wire cutting drive assembly 27 includes a wire cutting shaft 36 and a wire cutting fork crank 35. The wire cutting fork crank 35 is fixedly mounted on the wire cutting shaft 36. The lower swing end of the differential drive crank 24 is connected to the wire cutting slider 34. The wire cutting slider 34 is slidably connected in the slide groove of the wire cutting fork crank 35.

[0051] An embodiment provides a sewing machine, comprising the above-mentioned feeding mechanism capable of switching the differential ratio.

[0052] The use process of the tooling of the utility model is as follows:

[0053] By controlling the swing amplitude of the output shafts of the main feed motor 8 and the differential feed motor 13 through the electronic control module of the sewing machine, not only the stitch length of the main feed dog 32 and the differential feed dog 33 can be changed, but also the differential feeding function and the synchronous feeding function can be realized as required.

[0054] When the swing amplitudes of the swing output shafts of the main feeding motor 8 and the differential feeding motor 13 are the same (i.e., when the stitch lengths of the main feeding tooth 32 and the differential feeding tooth 33 are the same), it is synchronous feeding, that is, the differential ratio is 1:1; when the swing amplitudes of the swing output shafts of the main feeding motor 8 and the differential feeding motor 13 are different (i.e., when the stitch lengths of the main feeding tooth 32 and the differential feeding tooth 33 are different), it is differential feeding, that is, the differential ratio is 1:n (n can be greater than or less than 1). Therefore, by adjusting the different swing amplitudes of the swing output shafts of the main feeding motor 8 and the differential feeding motor 13 according to requirements, different feeding differential ratios can be formed to correspond to different sewing conditions, improve the adaptability of the fabric, and be consistent with the basic functions of the lower differential sewing machines on the market.

[0055] When the user needs to adjust the sewing mode, the electronic control module controls the relative timing coordination relationship between the main feeding motor 8 and the differential feeding motor 13 and the lifting tooth movement to realize the transformation of the four common feeding trajectories in the figure. Therefore, in the synchronous feeding and differential feeding modes, the differential feeding tooth 33 and the main feeding tooth 32 can not only achieve the same feeding trajectory but also different feeding trajectories, greatly enhancing the adaptability to different fabrics and various sewing conditions.

[0056] Compared with the prior art, the present application has at least the following beneficial technical effects:

[0057] The feeding mechanism in the present application has a simple structure. It can not only form a relatively independent feeding module but also be quickly installed on the bottom plate of the existing sewing machine, reducing the modification of the sewing machine, adapting to conventional flat sewing machines, and can also be selected according to customer needs whether to have the differential feeding function. The overall versatility is strong and the applicable range is wide.

[0058] The above are only the preferred embodiments of the present invention. It should be noted that for those of ordinary skill in the art, 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 mechanism capable of switching differential ratio, characterized in that: include: Bottom plate (1); A tooth-lifting shaft (2), the tooth-lifting shaft (2) being rotatably mounted below the base plate (1), and a main tooth-lifting fork (3) and a differential tooth-lifting fork (4) being mounted at the front end of the tooth-lifting shaft (2); A main feeding shaft (5), the main feeding shaft (5) is rotatably mounted below the bottom plate (1), the main feeding shaft (5) is parallel to the tooth lifting shaft (2), a main feeding front crank (6) is mounted at the front end of the main feeding shaft (5), and a main feeding tooth frame (7) is connected between the main feeding front crank (6) and the main tooth lifting fork (3); A main feeding motor (8), the main feeding motor (8) being installed below the bottom plate (1), and a main transmission four-link assembly (9) for driving the main feeding shaft (5) to reciprocate and swing is connected between the swing output shaft of the main feeding motor (8) and the rear end of the main feeding shaft (5); A differential feeding shaft (10), the differential feeding shaft (10) being rotatably coaxially arranged in the inner cavity of the main feeding shaft (5), a differential feeding front crank (11) being installed at the front end of the differential feeding shaft (10), and a differential feeding tooth frame (12) being connected between the differential feeding front crank (11) and the differential tooth lifting fork (4); A differential feeding motor (13) is installed below the base plate (1), and a differential transmission four-link assembly (14) for driving the differential feeding shaft (10) to reciprocate is connected between the swing output shaft of the differential feeding motor (13) and the rear end of the differential feeding shaft (10).

2. A feeding mechanism capable of switching differential ratio according to claim 1, characterized in that: It also includes an electric control module, which is electrically connected to the main feeding motor (8) and the differential feeding motor (13) and is capable of adjusting the reciprocating swing angles of the main feeding shaft (5) and the differential feeding shaft (10).

3. A feeding mechanism capable of switching differential ratio according to claim 1 or 2, characterized in that: A rotatable sleeve on the main feed shaft (5) is provided with a front shaft sleeve (15) and a rear shaft sleeve (16), and the front shaft sleeve (15) and the rear shaft sleeve (16) are fixedly installed in the installation hole below the bottom plate (1), a retaining ring (17) is provided on one axial side of the front shaft sleeve (15), and the retaining ring (17) is fixedly connected to the main feed shaft (5), and an external retaining spring (18) is provided on the other axial end of the front shaft sleeve (15), and the external retaining spring (18) is fixedly connected to the main feed shaft (5).

4. A feeding mechanism capable of switching differential ratio according to claim 3, characterized in that: The front end of the differential feeding shaft (10) axially extends to the outside of the main feeding shaft (5) and is fixedly connected to the differential feeding front crank (11); the front end of the differential feeding shaft (10) is fixedly mounted with an internal retaining spring (19), and the internal retaining spring (19) abuts against the front end surface of the main feeding shaft (5); the rear end of the differential feeding shaft (10) is fixedly mounted with a thrust ball bearing (20), and the thrust ball bearing (20) abuts against the rear end surface of the main feeding shaft (5).

5. A feeding mechanism capable of switching differential ratio according to claim 1 or 2, characterized in that: The main transmission four-link assembly (9) comprises a main driving crank (21), a main feeding connecting rod (22) and a main feeding rear crank (23); the main driving crank (21) is fixedly connected to the swing output shaft of the main feeding motor (8); the main feeding rear crank (23) is fixedly connected to the rear end of the main feeding shaft (5); one end of the main feeding connecting rod (22) is hinged to the main driving crank (21); and the other end of the main feeding connecting rod (22) is hinged to the main feeding rear crank (23).

6. A feeding mechanism capable of switching differential ratio according to claim 5, characterized in that: The differential transmission four-link assembly (14) comprises a differential drive crank (24), a differential feeding connecting rod (25) and a differential feeding rear crank (26); the differential drive crank (24) is fixedly connected to the swing output shaft of the differential feeding motor (13); the differential feeding rear crank (26) is fixedly connected to the rear end of the differential feeding shaft (10); and a thrust ball bearing (20) is provided between the differential feeding rear crank (26) and the rear end surface of the main feeding shaft (5); one end of the differential feeding connecting rod (25) is hinged to the differential drive crank (24); and the other end of the differential feeding connecting rod (25) is hinged to the differential feeding rear crank (26).

7. A feeding mechanism capable of switching differential ratio according to claim 6, characterized in that: The middle part of the differential drive crank (24) is fixedly connected to the swing output shaft of the differential feeding motor (13), the upper swing end of the differential drive crank (24) is hinged to the differential feeding connecting rod (25), and the lower swing end of the differential drive crank (24) is transmission-connected to the thread cutting drive assembly (27).

8. A feeding mechanism capable of switching differential ratio according to claim 1, characterized in that: A first motor bracket (28) and a second motor bracket (29) are detachably mounted below the base plate (1); the main feeding motor (8) is fixedly connected to the first motor bracket (28); and the differential feeding motor (13) is fixedly connected to the second motor bracket (29).

9. A sewing machine, characterized in that: The sewing machine comprises a feeding mechanism capable of switching a differential ratio as described in any one of claims 1 to 8.

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