CN220224534U - Lower differential feeding mechanism and sewing machine - Google Patents

Abstract

The utility model provides a lower differential feeding mechanism and a sewing machine, wherein the lower differential feeding mechanism comprises a first dental frame, a second dental frame, a first feeding tooth, a second feeding tooth, a first feeding driving source, a first feeding unit, a second feeding driving source and a second feeding unit, wherein the first dental frame and the second dental frame are arranged side by side, the first feeding tooth is fixed on the first dental frame, the second feeding tooth is fixed on the second dental frame, the first feeding driving source is connected with one end of the first dental frame through the first feeding unit, the second feeding driving source is connected with one end of the second dental frame through the second feeding unit, and the first feeding driving source and the second feeding driving source are two independent driving sources. In this application, adopt the pay-off of two independent driving sources to drive the pay-off of first pay-off tooth and the pay-off of second pay-off tooth respectively, so, just can conveniently adjust the gauge needle of first pay-off tooth and the gauge needle of second pay-off tooth through the output of control first pay-off driving source and second pay-off driving source, also conveniently adjust differential gauge needle promptly, and for electronic regulation, raise the efficiency.

Description

Lower differential feeding mechanism and sewing machine

Technical Field

The utility model relates to the technical field of sewing machines, in particular to a lower differential feeding mechanism and a sewing machine comprising the same.

Background

At present, two sets of tooth frames and feeding teeth are arranged in the sewing machine with the lower differential feeding function, different sewing effects can be realized through synchronous feeding or asynchronous feeding (namely differential feeding) of the two sets of tooth frames and the feeding teeth, and certain application occasions are realized on the market.

In general, the structure for realizing the differential function under the sewing machine is as follows: the feeding power of one set of tooth frame and feeding tooth is from the feeding mechanism in the sewing machine, the feeding power of the other set of tooth frame and feeding tooth is from the feeding mechanism of the sewing machine, namely the feeding shaft in the feeding mechanism is connected with one tooth frame through one set of differential connecting rod mechanism and is provided with a manual adjusting mechanism, the manual adjusting mechanism acts on the differential connecting rod mechanism and is used for changing the transmission efficiency of the differential connecting rod mechanism and realizing the manual adjustment of differential needle distance (namely differential feeding amount). Therefore, the conventional sewing machine has problems of complicated structure and inconvenient adjustment of differential stitch length, and particularly cannot be adjusted when the sewing is stopped in the middle.

Disclosure of Invention

In view of the above-mentioned drawbacks of the prior art, an object of the present utility model is to provide a lower differential feeding mechanism, which is convenient for adjusting differential gauge.

In order to achieve the above purpose, the utility model provides a lower differential feeding mechanism, which comprises a first dental frame, a second dental frame, a first feeding tooth, a second feeding tooth, a first feeding driving source, a first feeding unit, a second feeding driving source and a second feeding unit, wherein the first dental frame and the second dental frame are arranged side by side, the first feeding tooth is fixed on the first dental frame, the second feeding tooth is fixed on the second dental frame, the first feeding driving source is connected with one end of the first dental frame through the first feeding unit, the second feeding driving source is connected with one end of the second dental frame through the second feeding unit, and the first feeding driving source and the second feeding driving source are two independent driving sources.

Further, the first feeding driving source and the second feeding driving source are motors; the first feeding unit comprises a first feeding shaft rotatably supported in the bottom plate of the sewing machine, a first feeding assembly in transmission connection between a first feeding driving source and the first feeding shaft, and a second feeding assembly in transmission connection between the first feeding shaft and the first dental frame; the second feeding unit comprises a second feeding shaft rotatably supported in the bottom plate of the sewing machine, a third feeding assembly in transmission connection between a second feeding driving source and the second feeding shaft, and a fourth feeding assembly in transmission connection between the second feeding shaft and the second dental frame; the first feeding shaft and the second feeding shaft are coaxially arranged.

Further, the first feeding driving source is a main motor in the sewing machine, the first feeding assembly comprises a main shaft rotatably supported in the sewing machine shell, a feeding eccentric wheel fixed on the main shaft, a first feeding connecting rod, a first feeding oscillating rod, a second feeding oscillating rod, a feeding oscillating seat with a fixed rotation pivot and a first feeding crank fixed on the first feeding shaft, the main motor is connected with the main shaft, one end of the first feeding connecting rod is in rotary fit with the eccentric part of the feeding eccentric wheel, the other end of the first feeding connecting rod, one end of the first feeding oscillating rod and one end of the second feeding oscillating rod are coaxially hinged, the other end of the first feeding oscillating rod is hinged with the feeding oscillating seat, and the other end of the second feeding oscillating rod is hinged with the first feeding crank.

Further, the second feeding assembly comprises a first dental frame seat fixed on the first feeding shaft, and the first dental frame seat is hinged with the first dental frame through a first dental frame pin; the fourth feeding assembly comprises a second dental frame seat fixed on a second feeding shaft, and the second dental frame seat is hinged with a second dental frame through a second dental frame pin; the first dental frame seat and the second dental frame seat are arranged side by side along the axial direction of the first feeding shaft and the second feeding shaft, and the first dental frame pin and the second dental frame pin are coaxially arranged.

Further, the first feeding shaft is rotatably arranged in the second feeding shaft in a penetrating manner; along the axial direction of the first feeding shaft and the second feeding shaft, the first dental frame is arranged on the outer side of the second dental frame, the second feeding driving source is arranged on the inner side of the second dental frame, and the second feeding driving source and the second feeding unit are both arranged on the inner sides of the first dental frame and the first dental frame seat.

Further, the first feeding shaft comprises a first shaft section and a second shaft section which are connected in sequence, the outer diameter of the first shaft section is larger than that of the second shaft section, a shaft shoulder is formed at the joint of the first shaft section and the second shaft section, a first clamp spring groove is formed in the periphery of the second shaft section, the first feeding unit further comprises a first check ring clamped in the first clamp spring groove, the second feeding shaft is sleeved on the periphery of the second shaft section, and the first check ring and the shaft shoulder are respectively abutted against two ends of the second feeding shaft.

Further, the second feeding driving source is fixed at the bottom of the sewing machine bottom plate; the third feeding assembly comprises a second feeding crank fixed on a motor shaft of the second feeding driving source, a second feeding connecting rod and a third feeding crank fixed on the second feeding shaft, and two ends of the second feeding connecting rod are hinged with the second feeding crank and the third feeding crank respectively.

Further, a second snap spring groove is formed in the periphery of the second feeding shaft, the second feeding unit further comprises a second check ring clamped in the second snap spring groove and a feeding shaft sleeve fixed in a bottom plate of the sewing machine, the second feeding shaft is rotatably arranged in the feeding shaft sleeve in a penetrating mode, and the second check ring and the third feeding crank respectively lean against two ends of the feeding shaft sleeve.

The utility model also provides a sewing machine, wherein the lower differential feeding mechanism is assembled in the sewing machine.

Further, the sewing machine further comprises a feed lifting mechanism, the feed lifting mechanism comprises a feed lifting driving source, a feed lifting shaft rotatably supported in a sewing machine bottom plate, a feed lifting assembly connected between the feed lifting driving source and the feed lifting shaft in a transmission mode, a first feed lifting fork crank and a second feed lifting fork crank which are both fixed on the feed lifting shaft, a first feed lifting slider assembled in the first feed lifting fork crank in a sliding mode, and a second feed lifting slider assembled in the second feed lifting fork crank in a sliding mode, the first feed lifting slider is hinged to the other end of the first feed lifting frame, and the second feed lifting slider is hinged to the other end of the second feed lifting frame.

As described above, the lower differential feeding mechanism and the sewing machine according to the present utility model have the following advantages:

in this application, adopt the pay-off of two independent driving sources to drive the pay-off of first pay-off tooth and the pay-off of second pay-off tooth respectively, so, just can conveniently adjust the gauge needle of first pay-off tooth and the gauge needle of second pay-off tooth through the output of control first pay-off driving source and second pay-off driving source, also conveniently adjust differential gauge needle promptly, and for electronic regulation, raise the efficiency.

Drawings

Fig. 1 is a schematic structural view of a sewing machine in the present application.

Fig. 2 and 3 are schematic structural views of fig. 1 under different viewing angles, with the chassis, the bottom plate and the needle plate omitted.

Fig. 4 is an enlarged view of circle a of fig. 3.

Fig. 5 is an enlarged view of circle B of fig. 3.

Fig. 6 is a schematic structural view of a first feeding shaft in the present application.

Fig. 7 is a schematic structural view of a second feeding shaft in the present application.

Description of element reference numerals

10. First dental frame

20. Second dental frame

30. First feeding tooth

40. Second feeding tooth

50. First feeding unit

51. First feeding shaft

501. A first shaft section

502. Second shaft section

503. Shaft shoulder

504. First jump ring groove

52. Main shaft

53. Feeding eccentric wheel

54. First feeding connecting rod

55. First feeding swing rod

56. Second feeding swing rod

57. Feeding swing seat

58. First feeding crank

59. First dental frame seat

510. First dental articulator pin

511. First check ring

60. Second feeding driving source

70. Second feeding unit

71. Second feeding shaft

711. Second jump ring groove

72. Second dental frame seat

73. Second dental articulator pin

74. Second feeding crank

75. Second feeding connecting rod

76. Third feeding crank

77. Second retainer ring

78. Feeding shaft sleeve

80. Tooth lifting mechanism

81. Lifting shaft

82. First lifting tooth fork-shaped crank

83. Second lifting tooth fork crank

84. Lifting tooth eccentric wheel

85. Lifting tooth connecting rod

86. Lifting tooth crank

90. Casing of machine

110. Bottom plate

120. Needle plate

Detailed Description

Further advantages and effects of the present utility model will become apparent to those skilled in the art from the disclosure of the present utility model, which is described by the following specific examples.

It should be understood that the structures, proportions, sizes, etc. shown in the drawings are for illustration purposes only and should not be construed as limiting the utility model to the extent that it can be practiced, since modifications, changes in the proportions, or adjustments of the sizes, which are otherwise, used in the practice of the utility model, are included in the spirit and scope of the utility model which is otherwise, without departing from the spirit or scope thereof. Also, the terms such as "upper," "lower," "left," "right," "middle," and "a" and the like are used herein for descriptive purposes only and not for purposes of limitation, and are intended to limit the scope of the utility model as defined by the claims and the relative terms thereof as construed as corresponding to the claims.

It will also be understood that when an element is referred to as being "mounted" or "disposed" on another element, it can be directly on the other element or intervening elements may also be present. When an element is referred to as being "connected" to another element, it can be directly connected to the other element or be indirectly connected to the other element through intervening elements.

Furthermore, the descriptions of "first," "second," and the like, herein are for descriptive purposes only and are not to be construed as indicating or implying a relative importance or implicitly indicating the number of technical features indicated. Thus, a feature defining "a first" or "a second" may explicitly or implicitly include at least one such feature. In addition, the technical solutions of the embodiments may be combined with each other, but it is necessary to base that the technical solutions can be realized by those skilled in the art, and when the technical solutions are contradictory or cannot be realized, the combination of the technical solutions should be regarded as not exist and not within the protection scope of the present application.

The utility model provides a lower differential feeding mechanism and a sewing machine equipped with the same. As shown in fig. 1 and 2, the sewing machine includes a housing 90 and a base plate 110 both fixedly provided, a needle plate 120 fixed to the base plate 110, and a main shaft 52 rotatably supported in the housing 90. For convenience of description, in the following embodiments, the axial direction of the main shaft 52 is defined as the left-right direction, and the direction of the main shaft 52 toward the sewing machine head is the left direction, and the direction of the main shaft 52 toward the sewing machine tail is the right direction; the moving direction of the fabric when the sewing machine is forward sewing is defined as the front direction. Accordingly, as shown in fig. 1, the needle plate 120 is fixed to the left side of the bottom plate 110.

As shown in fig. 2 and 3, the lower differential feeding mechanism according to the present utility model includes a first rack 10 and a second rack 20 arranged side by side, a first feeding tooth 30 fixed on the first rack 10, a second feeding tooth 40 fixed on the second rack 20, a first feeding driving source, a first feeding unit 50, a second feeding driving source 60, and a second feeding unit 70, the first feeding driving source is connected to the front end of the first rack 10 through the first feeding unit 50, the second feeding driving source 60 is connected to the front end of the second rack 20 through the second feeding unit 70, and the first feeding driving source and the second feeding driving source 60 are two independent driving sources; the first feeding teeth 30 are distributed right behind the second feeding teeth 40.

In the sewing process of the sewing machine, the first feeding driving source drives the first dental frame 10 to reciprocate back and forth through the first feeding unit 50, the first feeding teeth 30 reciprocate back and forth synchronously with the first dental frame 10, and the first feeding teeth 30 execute feeding action and have a first needle pitch; the second feeding driving source 60 drives the second rack 20 to reciprocate back and forth through the second feeding unit 70, the second feeding teeth 40 reciprocate back and forth in synchronization with the second rack 20, the second feeding teeth 40 perform feeding actions and have a second pitch, and the difference between the first pitch and the second pitch is a differential pitch. When the first needle pitch of the first feeding tooth 30 is equal to the second needle pitch of the second feeding tooth 40, the first needle pitch and the second needle pitch are synchronously fed; when the first needle pitch of the first feeding tooth 30 is not equal to the second needle pitch of the second feeding tooth 40, the first needle pitch and the second needle pitch are fed in a differential mode. According to the feeding device, two independent driving sources are adopted to respectively drive feeding of the first feeding tooth 30 and feeding of the second feeding tooth 40, the first needle pitch of the first feeding tooth 30 can be adjusted by controlling output of the first feeding driving source, the second needle pitch of the second feeding tooth 40 can be adjusted by controlling output of the second feeding driving source 60, and then differential needle pitch can be conveniently adjusted, electronic adjustment is achieved, and efficiency is improved.

Further, the first feeding driving source and the second feeding driving source 60 are motors, preferably stepper motors, so that the control is convenient, the adjustment precision of the differential stitch is improved, the adjustment in the seam of the differential stitch can be realized, and the intelligent feeding device is more intelligent. As shown in fig. 2 and 3, the first feeding unit 50 includes a first feeding shaft 51 rotatably supported in the sewing machine base plate 110, a first feeding assembly drivingly connected between the first feeding driving source and the first feeding shaft 51, and a second feeding assembly drivingly connected between the first feeding shaft 51 and the first dental frame 10; the second feeding unit 70 includes a second feeding shaft 71 rotatably supported in the sewing machine base plate 110, a third feeding assembly drivingly connected between the second feeding driving source 60 and the second feeding shaft 71, and a fourth feeding assembly drivingly connected between the second feeding shaft 71 and the second dental frame 20; the first feeding shaft 51 and the second feeding shaft 71 are coaxially disposed and are parallel to the main shaft 52 of the sewing machine, and the first feeding shaft 51 and the second feeding shaft 71 are both extended straight left and right.

Further, the first feeding unit 50 adopts an original feeding unit in the sewing machine, thereby reducing the cost. Based on this, as shown in fig. 2, 3 and 5, the first feeding driving source is a main motor in the sewing machine, which is not shown in the drawings, and a motor shaft of the main motor is fixedly connected to the right end of the main shaft 52 through a coupling, and the main motor drives the main shaft 52 to rotate. The first feeding assembly comprises a main shaft 52, a feeding eccentric wheel 53 fixed on the main shaft 52, a first feeding connecting rod 54, a first feeding swing rod 55, a second feeding swing rod 56, a feeding swing seat 57 with a fixed rotation pivot, and a first feeding crank 58 fixed at the right end of the first feeding shaft 51, wherein the upper end of the first feeding connecting rod 54 is in rotary fit with the eccentric part of the feeding eccentric wheel 53, the lower end of the first feeding connecting rod 54, one end of the first feeding swing rod 55 and one end of the second feeding swing rod 56 are coaxially hinged, the other end of the first feeding swing rod 55 is hinged with the feeding swing seat 57, and the other end of the second feeding swing rod 56 is hinged with the first feeding crank 58. The second feeding assembly includes a first dental frame seat 59 fixed to the left end of the first feeding shaft 51, and the first dental frame seat 59 is hinged to the front end of the first dental frame 10 by a first dental frame pin 510 extending left and right.

Further, the structure of the second feeding unit 70 is preferably: as shown in fig. 2 to 4, the second feeding driving source 60 is fixed to the bottom of the sewing machine base plate 110 by a motor mounting plate; the third feeding assembly includes a second feeding crank 74 fixed on a motor shaft of the second feeding driving source 60, a second feeding connecting rod 75, and a third feeding crank 76 fixed on a right end of the second feeding shaft 71, both ends of the second feeding connecting rod 75 being hinged with the second feeding crank 74 and the third feeding crank 76, respectively. The fourth feeding assembly includes a second dental frame seat 72 fixed to the left end of the second feeding shaft 71, and the second dental frame seat 72 is hinged to the front end of the second dental frame 20 by a second dental frame pin 73 extending left and right. The first bracket pin 510 is provided coaxially with the second bracket pin 73.

Further, in order to optimize the structure of the sewing machine and reduce the volume of the sewing machine, in this embodiment, the arrangement manner of each part is as follows: as shown in fig. 2 and 3, the first feeding shaft 51 is rotatably provided in the second feeding shaft 71; along the axial direction of the first feeding shaft 51 and the second feeding shaft 71, the first rack mount 59 and the second rack mount 72 are arranged side by side, and the first rack 10 is arranged on the outside, i.e., the left side, of the second rack 20, the second feeding drive source 60 is arranged on the inside, i.e., the right side, of the second rack 20, and the second feeding drive source 60 and the second feeding unit 70 are both arranged on the inside, i.e., the right side, of the first rack 10 and the first rack mount 59, and therefore, the first rack mount 59 is arranged on the outside, i.e., the left side, of the second rack mount 72. The arrangement structure is compact and reasonable, and the length of the sewing machine in the left-right direction can be effectively reduced, so that the occupied volume of the sewing machine is reduced.

Further, as shown in fig. 6, the first feeding shaft 51 includes a first shaft section 501 and a second shaft section 502 which are sequentially connected, the outer diameter of the first shaft section 501 is larger than that of the second shaft section 502, the second shaft section 502 integrally extends axially leftwards from the left end of the first shaft section 501, a shaft shoulder 503 is formed at the joint of the first shaft section 501 and the second shaft section 502 of the first feeding shaft 51, and a first snap spring groove 504 is formed at the outer periphery of the second shaft section 502 of the first feeding shaft 51; as shown in fig. 4, the first feeding unit 50 further includes a first retainer ring 511 that is clamped in the first clamp spring groove 504, the second feeding shaft 71 is sleeved on the outer periphery of the second shaft section 502, and the first retainer ring 511 and the shaft shoulder 503 respectively abut against the left end and the right end of the second feeding shaft 71. The first retaining ring 511 and the shoulder 503 limit the first feeding shaft 51 in the axial direction, so that the first feeding shaft 51 is limited from moving in the left-right axial direction, but the rotation of the first feeding shaft 51 is not affected.

Further, as shown in fig. 4 and 7, a second clip spring groove 711 is formed on the outer periphery of the second feeding shaft 71, the second feeding unit 70 further includes a second clip ring 77 clamped in the second clip spring groove 711, and a feeding shaft sleeve 78 fixed in the sewing machine base plate 110, the second feeding shaft 71 rotatably penetrates the feeding shaft sleeve 78, and the second clip ring 77 and the third feeding crank 76 respectively abut against the left end and the right end of the feeding shaft sleeve 78. The second feeding shaft 71 is axially limited by the second retainer ring 77 and the third feeding crank 76, so that the left-right axial movement of the second feeding shaft 71 is limited, but the rotation of the second feeding shaft 71 is not affected.

The utility model also provides a sewing machine, wherein the lower differential feeding mechanism is assembled in the sewing machine. As shown in fig. 2 and 3, the sewing machine is further provided with a feed lifting mechanism 80, and the feed lifting mechanism 80 includes a feed lifting driving source, a feed lifting shaft 81 rotatably supported on a sewing machine base plate 110, a feed lifting assembly drivingly connected between the feed lifting driving source and the feed lifting shaft 81, a first feed lifting fork crank 82 and a second feed lifting fork crank 83 both fixed to the left end of the feed lifting shaft 81, a first feed lifting slider slidably mounted in the first feed lifting fork crank 82, and a second feed lifting slider slidably mounted in the second feed lifting fork crank 83, the first feed lifting slider being hinged to the rear end of the first frame 10, and the second feed lifting slider being hinged to the rear end of the second frame 20. In this embodiment, the lifting tooth driving source is also a main motor, and the lifting tooth assembly includes a main shaft 52, a lifting tooth eccentric wheel 84 on the fixed main shaft 52, a lifting tooth connecting rod 85, and a lifting tooth crank 86 fixed on the right end of the lifting tooth shaft 81, where the upper end of the lifting tooth connecting rod 85 is in running fit with the eccentric part of the lifting tooth eccentric wheel 84, and the lower end of the lifting tooth connecting rod 85 is hinged with the lifting tooth crank 86. Preferably, the feed eccentric 53 and the lifter eccentric 84 may be combined into one piece.

In the sewing process of the sewing machine, a main motor drives a main shaft 52 to rotate, the main shaft 52 drives a lifting tooth shaft 81 to reciprocate through a lifting tooth eccentric wheel 84, a lifting tooth connecting rod 85 and a lifting tooth crank 86, the lifting tooth shaft 81 drives a first tooth frame 10 and a second tooth frame 20 to synchronously reciprocate up and down through a first lifting tooth fork crank 82 and a first lifting tooth sliding block and a second lifting tooth fork crank 83 and a second lifting tooth sliding block, and then the first feeding tooth 30 and the second feeding tooth 40 synchronously reciprocate up and down, and the first feeding tooth 30 and the second feeding tooth 40 synchronously execute lifting tooth actions; the main shaft 52 drives the first feeding shaft 51 to reciprocate through the feeding eccentric wheel 53, the first feeding connecting rod 54, the first feeding swing rod 55, the second feeding swing rod 56, the feeding swing seat 57 and the first feeding crank 58, the first feeding shaft 51 drives the first dental articulator 10 to reciprocate back and forth through the first dental articulator 59, and the first feeding teeth 30 reciprocate back and forth along with the first dental articulator 10; at the same time, the motor shaft of the second feeding driving source 60 reciprocates, the second feeding shaft 71 is driven to reciprocate by the second feeding crank 74, the second feeding link 75 and the third feeding crank 76, the second feeding shaft 71 drives the second dental frame 20 to reciprocate back and forth by the second dental frame seat 72, and the second feeding teeth 40 reciprocate back and forth with the second dental frame 20. The second pitch of the second feeding teeth 40 is directly determined by the swing angle of the motor shaft of the second feeding drive source 60, and when the swing angle of the motor shaft of the second feeding drive source 60 is changed, the displacement of the back and forth reciprocating motion of the second feeding teeth 40 is also changed, so that the second pitch of the second feeding teeth 40 is changed.

Preferably, the sewing machine further comprises an operation panel, the operation panel and the second feeding driving source 60 are connected with an electronic control module of the sewing machine, and the change of the swinging angle of the second feeding driving source 60 is realized through the setting of parameters of the operation panel, so that the change of the second needle pitch of the second feeding teeth 40 is realized, and finally, the electronic adjustment of the differential needle pitch and the adjustment in the seam are realized. When the first needle pitch of the first feeding teeth 30 and the second needle pitch of the second feeding teeth 40 are equal, the two feeding teeth synchronously feed, and can adapt to the conventional fabric; when the output of the second feeding driving source 60 is controlled to enable the second needle pitch of the second feeding teeth 40 to be larger than the first needle pitch of the first feeding teeth 30, the special soft and thin fabric is sewn with good smooth sewing effect for stretching feeding; when the output of the second feeding driving source 60 is controlled to make the second pitch of the second feeding teeth 40 smaller than the first pitch of the first feeding teeth 30, the shrinkage feeding is suitable for some decoration sewing, and the diversity of sewing products is satisfied.

In summary, the present utility model effectively overcomes the disadvantages of the prior art and has high industrial utility value.

The above embodiments are merely illustrative of the principles of the present utility model and its effectiveness, and are not intended to limit the utility model. Modifications and variations may be made to the above-described embodiments by those skilled in the art without departing from the spirit and scope of the utility model. Accordingly, it is intended that all equivalent modifications and variations of the utility model be covered by the claims, which are within the ordinary skill of the art, be within the spirit and scope of the present disclosure.

Claims (10)

1. The utility model provides a lower differential feeding mechanism, includes first tooth frame (10) and second tooth frame (20) that set up side by side, fixes first feeding tooth (30) on first tooth frame (10), and fixes second feeding tooth (40) on second tooth frame (20), its characterized in that: the automatic feeding device comprises a first feeding driving source, a first feeding unit (50), a second feeding driving source (60) and a second feeding unit (70), wherein the first feeding driving source is connected with one end of a first dental frame (10) through the first feeding unit (50), the second feeding driving source (60) is connected with one end of a second dental frame (20) through the second feeding unit (70), and the first feeding driving source and the second feeding driving source (60) are two independent driving sources.

2. The lower differential feed mechanism of claim 1, wherein: the first feeding driving source and the second feeding driving source (60) are motors; the first feeding unit (50) comprises a first feeding shaft (51) rotatably supported in a sewing machine bottom plate (110), a first feeding assembly in transmission connection between a first feeding driving source and the first feeding shaft (51), and a second feeding assembly in transmission connection between the first feeding shaft (51) and the first dental frame (10); the second feeding unit (70) comprises a second feeding shaft (71) rotatably supported in a sewing machine bottom plate (110), a third feeding assembly in transmission connection between a second feeding driving source (60) and the second feeding shaft (71), and a fourth feeding assembly in transmission connection between the second feeding shaft (71) and the second dental frame (20); the first feeding shaft (51) and the second feeding shaft (71) are coaxially arranged.

3. The lower differential feed mechanism of claim 2, wherein: the first feeding driving source is a main motor in the sewing machine, the first feeding assembly comprises a main shaft (52) rotatably supported in a sewing machine shell (90), a feeding eccentric wheel (53) fixed on the main shaft (52), a first feeding connecting rod (54), a first feeding oscillating rod (55), a second feeding oscillating rod (56), a feeding oscillating seat (57) with a fixed rotation fulcrum and a first feeding crank (58) fixed on a first feeding shaft (51), the main motor is connected with the main shaft (52), one end of the first feeding connecting rod (54) is in running fit with an eccentric part of the feeding eccentric wheel (53), the other end of the first feeding connecting rod (54), one end of the first feeding oscillating rod (55) and one end of the second feeding oscillating rod (56) are coaxially hinged, the other end of the first feeding oscillating rod (55) is hinged with the feeding oscillating seat (57), and the other end of the second feeding oscillating rod (56) is hinged with the first feeding crank (58).

4. The lower differential feed mechanism of claim 2, wherein: the second feeding assembly comprises a first dental frame seat (59) fixed on a first feeding shaft (51), and the first dental frame seat (59) is hinged with the first dental frame (10) through a first dental frame pin (510); the fourth feeding assembly comprises a second dental frame seat (72) fixed on a second feeding shaft (71), and the second dental frame seat (72) is hinged with the second dental frame (20) through a second dental frame pin (73); the first and second dental frame seats (59, 72) are arranged side by side along the axial direction of the first and second feeding shafts (51, 71), and the first dental frame pin (510) and the second dental frame pin (73) are coaxially arranged.

5. The lower differential feed mechanism as claimed in claim 4, wherein: the first feeding shaft (51) is rotatably arranged in the second feeding shaft (71) in a penetrating way; along the axial direction of the first feeding shaft (51) and the second feeding shaft (71), the first dental frame (10) is arranged on the outer side of the second dental frame (20), the second feeding driving source (60) is arranged on the inner side of the second dental frame (20), and the second feeding driving source (60) and the second feeding unit (70) are both arranged on the inner sides of the first dental frame (10) and the first dental frame seat (59).

6. The lower differential feed mechanism of claim 5, wherein: the first feeding shaft (51) comprises a first shaft section (501) and a second shaft section (502) which are sequentially connected, the outer diameter of the first shaft section (501) is larger than that of the second shaft section (502), a shaft shoulder (503) is formed at the joint of the first shaft section (501) and the second shaft section (502) of the first feeding shaft (51), a first clamp spring groove (504) is formed in the periphery of the second shaft section (502), the first feeding unit (50) further comprises a first check ring (511) clamped in the first clamp spring groove (504), the second feeding shaft (71) is sleeved on the periphery of the second shaft section (502), and the first check ring (511) and the shaft shoulder (503) are respectively abutted to two ends of the second feeding shaft (71).

7. The lower differential feed mechanism of claim 2, wherein: the second feeding driving source (60) is fixed at the bottom of the sewing machine bottom plate (110); the third feeding assembly comprises a second feeding crank (74) fixed on a motor shaft of the second feeding driving source (60), a second feeding connecting rod (75) and a third feeding crank (76) fixed on the second feeding shaft (71), and two ends of the second feeding connecting rod (75) are hinged with the second feeding crank (74) and the third feeding crank (76) respectively.

8. The lower differential feed mechanism of claim 7, wherein: the periphery of second pay-off axle (71) has seted up second jump ring groove (711), second pay-off unit (70) still include card establish second retaining ring (77) in second jump ring groove (711) and fix pay-off axle sleeve (78) in sewing machine bottom plate (110), second pay-off axle (71) rotatably wear to establish in pay-off axle sleeve (78), second retaining ring (77) and third pay-off crank (76) support respectively and lean on the both ends of pay-off axle sleeve (78).

9. A sewing machine, characterized in that: the sewing machine is equipped with the lower differential feeding mechanism as claimed in any one of claims 1 to 8.

10. The sewing machine of claim 9, wherein: the sewing machine is characterized by further comprising a feed lifting mechanism (80), wherein the feed lifting mechanism (80) comprises a feed lifting driving source, a feed lifting shaft (81) rotatably supported in a sewing machine bottom plate (110), a feed lifting assembly connected between the feed lifting driving source and the feed lifting shaft (81) in a transmission mode, a first feed lifting fork crank (82) and a second feed lifting fork crank (83) which are both fixed on the feed lifting shaft (81), a first feed lifting slider slidably assembled in the first feed lifting fork crank (82) and a second feed lifting slider slidably assembled in the second feed lifting fork crank (83), the first feed lifting slider is hinged to the other end of the first feed lifting frame (10), and the second feed lifting slider is hinged to the other end of the second feed lifting frame (20).