CN220224568U - Bottom thread tension control mechanism and sewing machine - Google Patents

Abstract

The utility model discloses a bottom thread tension control mechanism and a sewing machine, comprising a wire-beating frame, wherein a first avoiding groove is arranged on the wire outlet side of the wire-beating frame, and a second avoiding groove is arranged on the wire inlet side of the wire-beating frame; the wire bonding sheet is arranged above the first avoiding groove, and a wire bonding guide groove is formed in the wire bonding sheet; the wire bonding cam is arranged below the first avoiding groove; the bottom line control sheet is arranged above the second avoidance groove, and is provided with a bottom line control groove; the bottom line control cam is arranged below the second avoidance groove, and the bottom line control cam and the wire bonding cam are coaxially arranged and can synchronously rotate; the first wire passing piece is fixedly arranged on two sides of the wire bonding sheet and the bottom wire control sheet. The utility model achieves the control of the bottom line tension by controlling the bottom line quantity, reduces the effect of the bottom line tension on the fabric when the thin elastic fabric is sewn, and avoids the fabric supply phenomenon caused by the bottom line pulling.

Description

Bottom thread tension control mechanism and sewing machine

Technical Field

The utility model relates to the technical field of bottom thread control of sewing machines, in particular to a bottom thread tension control mechanism and a sewing machine.

Background

In the actual sewing process, the requirements of the sewing machine are different when fabrics with different thicknesses are processed. When some special high-end thin elastic fabrics are processed, the fabrics are easy to generate arching, and part of arching cannot be thoroughly solved through debugging and can only be compensated through later ironing.

For the seam, the biggest influencing factor causing the arch of the fabric is the tightness of the bottom thread, so how to control the tension of the bottom thread, so that the effect of the tension of the bottom thread on the fabric is reduced when the thin elastic fabric is sewn, thereby avoiding the phenomenon that the bottom thread is pulled to cause the fabric to be supplied, and the technical problem to be solved by the person in the field is urgent.

Disclosure of Invention

In view of the above, the present utility model aims to provide a bobbin thread tension control mechanism to solve the technical problem that the existing thin fabric is easy to arch when being sewn.

The technical scheme adopted by the utility model is as follows: a bobbin thread tension control mechanism comprising:

the wire-bonding frame is characterized in that a first avoiding groove is formed in the wire outlet side of the wire-bonding frame, and a second avoiding groove is formed in the wire inlet side of the wire-bonding frame;

the wire bonding sheet is arranged above the first avoiding groove, and a wire bonding guide groove is formed in the wire bonding sheet;

the wire bonding cam is arranged below the first avoiding groove;

the bottom line control sheet is arranged above the second avoiding groove, and a bottom line control groove is formed in the bottom line control sheet;

the bottom line control cam is arranged below the second avoidance groove, and is coaxially arranged with the wire bonding cam and can synchronously rotate;

the first wire passing piece is fixedly arranged on two sides of the wire bonding sheet and the bottom wire control sheet;

when the bottom line control cam and the wire bonding cam rotate circumferentially, the contact time of the bottom line control cam and the bottom line is later than the wire bonding start time of the wire bonding cam to the bottom line, and the separation time of the bottom line control cam and the bottom line is earlier than the wire bonding end time of the wire bonding cam to the bottom line.

Preferably, the bottom line tension control mechanism further comprises a mounting frame, the wire-bonding frame comprises a mounting portion and a fixed connection portion which are vertically and fixedly connected, the fixed connection portion is fixedly connected with the mounting frame, and a first avoiding groove and a second avoiding groove are formed in the mounting portion in parallel.

Preferably, the installation part is obliquely arranged, the first avoiding groove is an open type avoiding groove with an opening at the bottom end, and the second avoiding groove is a closed type avoiding groove.

Preferably, the fixed connection part is rotationally connected with the mounting frame, and a clamp spring is arranged between the mounting frame and the mounting part.

Preferably, one side of the mounting frame is fixedly connected with a wire clamping device assembly, and the wire clamping device assembly is located on the wire inlet side of the wire bonding frame.

Preferably, the wire bonding sheet comprises a guiding part and a first connecting part which are vertically and fixedly connected, the first connecting part is fixedly connected with the wire bonding frame, the guiding part is arranged right above the first avoiding groove, and the guiding part is provided with a wire bonding guiding groove parallel to the wire bonding frame.

Preferably, the wire bonding cam is provided with a wire bonding accommodation gap corresponding to the guide part.

Preferably, the bottom line control piece comprises a second connecting part and a control part which are fixedly connected, the second connecting part is fixedly connected with the wire bonding frame, the control part is arranged right above the second avoiding groove, the control part is provided with a bottom line control groove, the top end of the bottom line control groove is positioned above the wire bonding guide groove, and the bottom end of the bottom line control groove is positioned below the wire bonding guide groove.

Preferably, the second connecting part is provided with a first connecting long slot hole for adjusting the bottom line quantity.

Preferably, the bottom line control cam is provided with a bottom line control gap corresponding to the control part.

Preferably, the first wire passing piece comprises a third connecting part and a wire passing part which are vertically and fixedly connected, the third connecting part is detachably and fixedly connected with the wire bonding frame, and the wire passing part is provided with a wire passing hole.

Another object of the present utility model is to provide a sewing machine, including the above-mentioned bottom thread tension control mechanism and a frame, a second thread passing member, and a looper, wherein the mounting frame of the bottom thread tension control mechanism is fixedly connected with the frame, the looper is disposed on a wire outgoing side of a wire-bonding frame of the bottom thread tension control mechanism, and the second thread passing member is disposed between the looper and the wire-bonding frame and is fixedly connected with the frame.

The utility model has the beneficial effects that:

according to the utility model, the bottom line control sheet parallel to the wire bonding sheet is arranged on the wire inlet side of the wire bonding frame, and the bottom line control cam is coaxially and fixedly connected on the wire inlet side of the wire bonding cam, and in the synchronous rotation process of the bottom line control cam and the wire bonding cam, the control of the bottom line tension in the wire bonding process can be realized by controlling the contact time and the separation time of the bottom line control cam and the bottom line, so that the acting force of the bottom line tension on the fabric can be reduced when the thin elastic fabric is sewn, and the fabric arching phenomenon caused by pulling the bottom line is avoided.

Drawings

FIG. 1 is a schematic diagram of a base string tension control mechanism according to the present utility model;

FIG. 2 is a diagram of the positional relationship of a wire bonding frame, a wire bonding cam, and a base wire control cam;

FIG. 3 is a diagram showing the positional relationship between a wire bonding frame and a first wire passing member;

FIG. 4 is a schematic structural view of a wire bonding frame;

FIG. 5 is a diagram of the positional relationship of the wire frame and the mounting frame;

FIG. 6 is a schematic structural view of a bonding pad;

FIG. 7 is a schematic view of the structure of the ground wire control sheet;

FIG. 8 is a schematic structural view of a first wire bonding member;

FIG. 9 is a schematic diagram of the wire bonding cam;

FIG. 10 is a reference view showing the state of use of the bobbin thread tension control mechanism according to the present utility model;

FIG. 11 is a first state diagram of the positional relationship of the wire bonding cam, the ground wire control cam, the wire bonding sheet and the ground wire control sheet;

FIG. 12 is a second state diagram of the positional relationship of the wire bonding cam, the ground wire control cam, the wire bonding sheet and the ground wire control sheet;

fig. 13 is a state diagram three of the positional relationship of the wire bonding cam, the ground wire control cam, the wire bonding sheet and the ground wire control sheet;

fig. 14 is a state diagram of the positional relationship of the wire bonding cam, the ground wire control cam, the wire bonding sheet and the ground wire control sheet;

FIG. 15 is a bottom line morphology corresponding to FIG. 12;

FIG. 16 is a bottom line morphology corresponding to FIG. 13;

fig. 17 is a schematic structural view of the sewing machine.

The reference numerals in the drawings illustrate:

1. a wire gripper assembly; 2. a mounting frame; 3. a bobbin thread control sheet; 4. wire-laying frame; 5. a bobbin thread control cam; 6. a wire bonding cam; 7. a first wire passing member; 8. a wire bonding sheet; 9. a second wire passing member; 10. a curved needle; 11. a frame; 12. a first avoidance groove; 13. a second avoidance groove; 14. a mounting part; 15. a fixed connection part; 16. a mounting hole; 17. a fastening screw; 18. an axial screw; 19. clamping springs; 20. a guide part; 21. a first connection portion; 22. wire bonding guide grooves; 23. a second connecting portion; 24. a first connecting slot; 25. a control unit; 26. a bobbin thread control groove; 27. a third connecting portion; 28. a second connecting slot; 29. a wire passing portion; 30. a wire through hole; 31. wire bonding accommodating gaps; 32. the bobbin thread controls the gap.

Detailed Description

The following describes the embodiments of the present utility model in further detail with reference to the accompanying drawings. These embodiments are merely illustrative of the present utility model and are not intended to be limiting.

In the description of the present utility model, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. indicate orientations or positional relationships based on the orientations or positional relationships shown in the drawings, are merely for convenience in describing the present utility model and simplifying the description, and do not indicate or imply that the apparatus or elements referred to must have a specific orientation, be configured and operated in a specific orientation, and thus should not be construed as limiting the present utility model. Furthermore, the terms "first," "second," and the like, are used for descriptive purposes only and are not to be construed as indicating or implying relative importance.

In the description of the present utility model, it should be noted that, unless explicitly specified and limited otherwise, the terms "mounted," "connected," and "connected" are to be construed broadly, and may be either fixedly connected, detachably connected, or integrally connected, for example; can be mechanically or electrically connected; can be directly connected or indirectly connected through an intermediate medium, and can be communication between two elements. The specific meaning of the above terms in the present utility model can be understood by those of ordinary skill in the art according to the specific circumstances.

Furthermore, in the description of the present utility model, unless otherwise indicated, the meaning of "a plurality" is two or more.

1-17, a bottom thread tension control mechanism for adjusting the bottom thread tension during sewing; the bobbin thread tension control mechanism includes:

the wire-bonding frame 4, the wire-outlet side of the wire-bonding frame 4 is provided with a first avoiding groove 12, and the wire-inlet side of the wire-bonding frame 4 is provided with a second avoiding groove 13.

The bonding sheet 8 is fixedly arranged right above the first avoiding groove 12, and the bonding sheet 8 is provided with a bonding guide groove 22.

A wire bonding cam 6, the wire bonding cam 6 being disposed directly below the first escape groove 12.

The bottom line control sheet 3 is fixedly arranged right above the second avoiding groove 13, and the bottom line control sheet 3 is provided with a bottom line control groove 26.

The bottom line control cam 5 is provided directly below the second escape groove 13, and the bottom line control cam 5 is coaxially provided with the wire bonding cam 6 and can rotate in synchronization therewith.

The number of the first wire passing pieces 7 is plural, and the plural first wire passing pieces 7 are fixedly arranged at both sides of the bonding sheet 8 and the ground wire control sheet 3.

When the bottom wire control cam 5 and the wire bonding cam 6 rotate circumferentially, the contact time of the bottom wire control cam 5 and the bottom wire is later than the wire bonding start time of the wire bonding cam 6 to the bottom wire, and the separation time of the bottom wire control cam 5 and the bottom wire is earlier than the wire bonding end time of the wire bonding cam 6 to the bottom wire.

According to the method, the bottom line control sheet 3 parallel to the wire bonding sheet 8 is arranged on the wire bonding side of the wire bonding frame 4, the bottom line control cam 5 is fixedly connected to the wire bonding side of the wire bonding cam 6 coaxially, the contact time and the separation time of the bottom line control cam 5 and the bottom line are controlled through the bottom line control cam 5 in the synchronous rotation process of the bottom line control cam 6, the control of the bottom line tension in the wire bonding process is realized, and therefore the acting force of the bottom line tension on the fabric can be reduced when thin elastic fabric is sewn, and the fabric arching phenomenon caused by pulling of the bottom line is avoided.

In one embodiment, as shown in fig. 1 and 5, the bottom wire tension control mechanism further comprises a mounting frame 2, and the mounting frame 2 can be detachably and fixedly mounted on a frame 11 of the sewing machine; the wire-bonding frame 4 comprises a mounting part 14 and a fixed connection part 15 which are vertically and fixedly connected, wherein the fixed connection part 15 is fixedly connected with the mounting frame 2, and a first avoiding groove 12 and a second avoiding groove 13 are arranged on the mounting part 14 in parallel.

Specifically, the mounting portion 14 and the fixed connection portion 15 are both plate-shaped, and the fixed connection portion 15 is vertically and fixedly connected to one end of the mounting portion 14; the fixed connection part 15 is arranged along the vertical direction, and the fixed connection part 15 is fixedly connected to the left side of the mounting frame 2; the installation frame 2 is L-shaped as a whole, and the installation frame 2 comprises a horizontal part and a vertical part, wherein the horizontal part can be fixedly connected with the frame 11, and the vertical part is fixedly connected with the fixed connection part 15 of the wire-bonding frame 4.

In a specific embodiment, as shown in fig. 1, 2, 3 and 4, the mounting portion 14 of the wire frame 4 is disposed obliquely, that is, one end of the mounting portion 14 near the frame 11 is located at a high position, and one end of the mounting portion 14 far from the frame 11 is located at a low position (for the wire frame 4, refer to patent 2019102862208); the first avoiding groove 12 is an open avoiding groove with an opening at the bottom end, namely the first avoiding groove 12 is U-shaped; the second avoiding groove 13 is a closed avoiding groove, that is, the second avoiding groove 13 is rectangular.

This is so arranged because: the wire bonding time of the wire bonding cam 6 to the bottom wire is longer than the wire bonding time of the bottom wire control cam 5 to the bottom wire, and the radial size of the wire bonding cam 6 is longer than the radial size of the bottom wire control cam 5, so that the wire bonding cam 6 is arranged below the open avoidance groove, and smooth rotation of the wire bonding cam 6 can be ensured.

In a specific embodiment, as shown in fig. 1 and 5, the fixed connection portion 15 of the wire-bonding frame 4 is rotatably connected to the mounting frame 2, and a clamp spring 19 is provided between the mounting frame 2 and the mounting portion 14.

Specifically, the fixed connection part 15 is disposed at the left side of the mounting frame 2, and the fixed connection part 15 is rotatably connected with the mounting frame 2 through an axial screw 18, so that the wire-bonding frame 4 can rotate around the axial screw 18 in a vertical plane; the clamping spring 19 is fixedly installed on the installation frame 2, the clamping spring 19 is located under the installation portion 14 of the wire-bonding frame 4, the top end of the clamping spring 19 is connected with the installation portion 14, limiting and fixing of the wire-bonding frame 4 are achieved through elastic force of the clamping spring 19, and meanwhile threading is facilitated.

In one embodiment, as shown in fig. 1 and 5, a wire clamping assembly 1 is fixedly connected to one side of the mounting frame 2, and the wire clamping assembly 1 is located on the wire feeding side of the wire bonding frame 4, and the wire clamping assembly 1 is used for clamping and stabilizing a bottom wire.

It should be noted that, the wire holder assembly 1 is in the prior art, and will not be described herein.

In a specific embodiment, as shown in fig. 1, 3 and 6, the bonding pad 8 includes a guiding portion 20 and a first connecting portion 21 that are vertically and fixedly connected, the guiding portion 20 and the first connecting portion 21 are both plate-shaped, the first connecting portion 21 is disposed on the upper surface of the bonding frame 4 in parallel, and the first connecting portion 21 is detachably and fixedly connected with the bonding frame 4 through a fastening bolt.

The guiding part 20 is arranged right above the first avoiding groove 12, and the guiding part 20 is provided with a wire bonding guiding groove 22, and the wire bonding guiding groove 22 is parallel to the wire bonding frame 4 and the first avoiding groove 12, so that when the wire bonding cam 6 performs wire bonding action on the bottom wire, the bottom wire can move upwards obliquely along the wire bonding guiding groove 22 to form a shape like a Chinese character 'ji'.

In one embodiment, as shown in fig. 2 and 9, the wire bonding cam 6 is provided with a wire bonding accommodation gap 31 corresponding to the guiding portion 20.

This is so arranged because: in the process of rotating the wire bonding cam 6, when the wire bonding cam 6 performs wire bonding action on the bottom wire, the guide part 20 of the wire bonding sheet 8 can enter the wire bonding accommodating gap 31, so that the wire bonding cam 6 can apply wire bonding force on the bottom wire on two sides of the wire bonding sheet 8.

In other embodiments, the wire bonding cam 6 may also be composed of two identical single-piece cams, and the wire bonding accommodation gap 31 is formed between the two single-piece cams.

In a specific embodiment, as shown in fig. 1, 3 and 7, the bottom line control piece 3 includes a second connecting portion 23 and a control portion 25 that are vertically and fixedly connected, the second connecting portion 23 and the control portion 25 are both plate-shaped, the second connecting portion 23 is disposed on the upper surface of the wire frame 4 in parallel, and the second connecting portion 23 is detachably and fixedly connected with the wire frame 4 through a fastening bolt.

The control part 25 is arranged right above the second avoiding groove 13, and a bottom line control groove 26 is arranged on the control part 25, the top end of the bottom line control groove 26 is positioned above the wire bonding guide groove 22, and the bottom end of the bottom line control groove 26 is positioned below the wire bonding guide groove 22; at the same time, the projection of the bottom wire control cam 5 in the axial direction is located entirely within the outer contour of the wire bonding cam 6.

This is so arranged because: when the top end of the bottom wire control groove 26 is located above the wire bonding guide groove 22 and the bottom end of the bottom wire control groove 26 is located below the wire bonding guide groove 22, the contact time of the bottom wire control cam 5 and the bottom wire is later than the wire bonding start time of the bottom wire by the wire bonding cam 6 when the bottom wire control cam 5 and the wire bonding cam 6 rotate circumferentially, and the separation time of the bottom wire control cam 5 and the bottom wire is earlier than the wire bonding end time of the wire bonding cam 6 to the bottom wire, namely, the control of the bottom wire tension by the bottom wire control cam 5 can be realized when the wire bonding cam 6 performs wire bonding action.

In one embodiment, as shown in fig. 4 and 7, the second connecting portion 23 is provided with a first connecting slot 24 for adjusting the amount of the bottom wire.

This is so arranged because: the installation portion 14 of the wire-bonding frame 4 is provided with a plurality of installation holes 16, after the second connection portion 23 is provided with the first connection long slot 24, when the second connection portion 23 is fixedly connected with the wire-bonding frame 4 by using the fastening bolt, the adjustment of the installation position of the bottom wire control sheet 3 on the wire-bonding frame 4, that is, the adjustment of the upper and lower positions of the bottom wire control sheet 3 is realized by adjusting the alignment position of the first connection long slot 24 and the installation holes 16, and then the control of the bottom wire quantity is realized.

In one embodiment, as shown in fig. 2 and 10, the bottom line control cam 5 is provided with a bottom line control gap 32 corresponding to the control portion 25.

This is so arranged because: during the rotation of the bobbin thread control cam 5, when the bobbin thread control cam 5 performs the bobbin thread bonding, the control section 25 of the bobbin thread control section 3 can enter the bobbin thread control gap 32 so that the bobbin thread control cam 5 can apply the bonding force to the bobbin thread on both sides of the bobbin thread control section 3.

In a specific embodiment, as shown in fig. 3 and 8, the first wire passing member 7 includes a third connecting portion 27 and a wire passing portion 29 that are vertically and fixedly connected, the third connecting portion 27 and the wire passing portion 29 are both plate-shaped, the third connecting portion 27 is disposed on the upper surface of the wire bonding frame 4 in parallel, the third connecting portion 27 is detachably and fixedly connected with the wire bonding frame 4 through a fastening bolt, and the wire passing portion 29 is provided with a wire passing hole 30.

Preferably, the third connecting portion 27 is provided with a second connecting slot 28, so that the position of the first wire passing member 7 on the wire bonding frame 4 can be adjusted, that is, the position of the wire passing hole 30 on the wire bonding frame 4 can be adjusted, and the up-down position of the first wire passing member 7 can be adjusted conveniently; at the same time, the end of the third connecting portion 27 is fixedly connected with one or two wire passing portions 29, that is, the end of the first wire passing member 7 is provided with one or two wire passing holes 30.

More preferably, the wire passing holes 30 of all the first wire passing pieces 7 mounted on the wire bonding frame 4 are coaxially arranged.

An embodiment, as shown in fig. 17, a sewing machine comprising the above-described bobbin thread tension control mechanism and frame 11 and second thread passing member 9 and looper 10; wherein, the mounting frame 2 of the bottom line tension control mechanism is detachably and fixedly connected with the frame 11 through a fastening screw 17, the curved needle 10 is arranged on the outgoing line side of the wire-bonding frame 4 of the bottom line tension control mechanism, and a plurality of second wire passing pieces 9 are arranged between the curved needle 10 and the wire-bonding frame 4 and are fixedly connected with the frame 11; meanwhile, the wire bonding cam 6 and the wire bonding control cam 5 of the wire bonding tension control mechanism are coaxially and fixedly arranged on a wire bonding shaft (not shown in the figure), and the wire bonding shaft and the main shaft of the machine head synchronously rotate.

The working principle of the bottom line tension control mechanism of the utility model is as follows:

as shown in fig. 11, at this time, at the initial position, the needle is at the highest point, the curved needle 10 is at the leftmost position, and neither the wire bonding cam 6 nor the wire bonding control cam 5 acts on the wire bonding; when the wire-bonding cam 6 rotates in the counterclockwise direction to be in contact with the base wire, the wire-bonding start time of the wire-bonding cam 6 is this time, and the base wire control cam 5 is not in contact with the base wire.

As shown in fig. 12 and 15, the wire bonding cam 6 rotates in a counterclockwise direction to a wire bonding state, at this time, the wire bonding cam 6 has completed partial wire bonding, and the wire bonding control cam 5 has just started wire bonding, at this time, the contact time between the wire bonding control cam 5 and the wire bonding; the curved needle 10 moves from left to right, and the wire-bonding cam 6 has completed partial wire bonding, which causes the bottom wire above the first avoiding groove 12 to be shaped like a Chinese character 'ji', and the bottom wire tension will become significantly larger, which causes the wire-bonding requirement above the second avoiding groove 13 to come from the right more, that is, the wire-bonding side (also called the wire-supplying end) of the wire-bonding frame 4, rather than the wire-bonding side (also called the curved needle end).

As shown in fig. 13 and 16, when the bottom wire control cam 5 rotates to a state that the bottom wire has been released from the bottom wire control cam 5 and is in a loose state, the time for releasing the bottom wire control cam 5 from the bottom wire is the time for releasing the bottom wire, the wire bonding cam 6 does not reach the position of the maximum wire bonding amount, that is, the wire bonding cam 6 does not rotate to the wire bonding end time, and in the subsequent rotating wire bonding process of the wire bonding cam 6, the bottom wire bonding amount of the wire bonding cam 6 is basically sourced from the position of the bottom wire control cam 5, so that the situation that the wire bonding tension is excessively high in stages is reduced through the control and compensation of the bottom wire control cam 5, the situation of tightening the bottom wire can be improved, and the arch phenomenon of fabric is not easy to occur.

The angle between the wire bonding cam 6 and the bottom line control cam 5 can be adjusted according to different working conditions, and the bottom line control quantity can be adjusted through the up-down position of the bottom line control piece 3.

Compared with the prior art, the application has the following technical effects:

according to the method, the control of the bottom line tension is achieved through the control of the bottom line quantity, when the thin elastic fabric is sewn, the effect of the bottom line tension on the fabric is reduced, and the fabric supply phenomenon caused by bottom line pulling is avoided.

The foregoing is merely a preferred embodiment of the present utility model, and it should be noted that modifications and substitutions can be made by those skilled in the art without departing from the technical principles of the present utility model, and these modifications and substitutions should also be considered as being within the scope of the present utility model.

Claims (12)

1. A bobbin thread tension control mechanism comprising:

the wire-bonding frame (4), the wire-outlet side of the wire-bonding frame (4) is provided with a first avoiding groove (12), and the wire-inlet side of the wire-bonding frame (4) is provided with a second avoiding groove (13);

the wire bonding sheet (8), the wire bonding sheet (8) is arranged above the first avoiding groove (12), and the wire bonding sheet (8) is provided with a wire bonding guide groove (22);

the wire bonding cam (6) is arranged below the first avoidance groove (12);

the bottom line control piece (3), the bottom line control piece (3) is arranged above the second avoiding groove (13), and a bottom line control groove (26) is arranged on the bottom line control piece (3);

the bottom line control cam (5) is arranged below the second avoidance groove (13), and the bottom line control cam (5) and the wire bonding cam (6) are coaxially arranged and can synchronously rotate;

the first wire passing piece (7), the first wire passing piece (7) is fixedly arranged at two sides of the wire bonding sheet (8) and the bottom wire control sheet (3);

when the bottom line control cam (5) and the wire bonding cam (6) rotate circumferentially, the contact time of the bottom line control cam (5) and the bottom line is later than the wire bonding starting time of the wire bonding cam (6) to the bottom line, and the detachment time of the bottom line control cam (5) and the bottom line is earlier than the wire bonding time of the wire bonding cam (6) to the bottom line.

2. The bottom line tension control mechanism according to claim 1, further comprising a mounting frame (2), wherein the wire-bonding frame (4) comprises a mounting portion (14) and a fixed connection portion (15) which are vertically and fixedly connected, the fixed connection portion (15) is fixedly connected with the mounting frame (2), and the mounting portion (14) is provided with a first avoiding groove (12) and a second avoiding groove (13) in parallel.

3. The bobbin thread tension control mechanism according to claim 2, wherein the mounting portion (14) is disposed obliquely, the first avoiding groove (12) is an open-type avoiding groove with an open bottom end, and the second avoiding groove (13) is a closed-type avoiding groove.

4. A bottom line tension control mechanism according to claim 2, characterized in that the fixed connection (15) is in rotational connection with the mounting frame (2) and that a snap spring (19) is provided between the mounting frame (2) and the mounting portion (14).

5. A bottom line tension control mechanism according to claim 2, characterized in that one side of the mounting frame (2) is fixedly connected with a wire gripper assembly (1), and the wire gripper assembly (1) is located at the wire inlet side of the wire-bonding frame (4).

6. The bobbin thread tension control mechanism according to claim 1, wherein the thread bonding sheet (8) comprises a guiding part (20) and a first connecting part (21) which are vertically and fixedly connected, the first connecting part (21) is fixedly connected with the thread bonding frame (4), the guiding part (20) is arranged right above the first avoiding groove (12), and the guiding part (20) is provided with a thread bonding guiding groove (22) parallel to the thread bonding frame (4).

7. The bobbin thread tension control mechanism as recited in claim 6, wherein the thread routing cam (6) is provided with a thread routing accommodation gap (31) corresponding to the guide portion (20).

8. The bobbin thread tension control mechanism according to claim 6, wherein the bobbin thread control sheet (3) comprises a second connecting part (23) and a control part (25) which are fixedly connected, the second connecting part (23) is fixedly connected with the thread-laying frame (4), the control part (25) is arranged right above the second avoiding groove (13), the control part (25) is provided with a bobbin thread control groove (26), the top end of the bobbin thread control groove (26) is positioned above the thread-laying guide groove (22), and the bottom end of the bobbin thread control groove (26) is positioned below the thread-laying guide groove (22).

9. A bobbin thread tension control mechanism as claimed in claim 8, wherein said second connecting portion (23) is provided with a first connecting slot (24) for adjusting the amount of bobbin thread.

10. A bobbin thread tension control mechanism as claimed in claim 8, wherein the bobbin thread control cam (5) is provided with a bobbin thread control gap (32) corresponding to the control section (25).

11. The bottom line tension control mechanism according to claim 1, wherein the first wire passing member (7) comprises a third connecting portion (27) and a wire passing portion (29) which are vertically and fixedly connected, the third connecting portion (27) is detachably and fixedly connected with the wire bonding frame (4), and the wire passing portion (29) is provided with a wire passing hole (30).

12. The sewing machine comprises the bottom line tension control mechanism as claimed in any one of claims 1 to 11, and is characterized by further comprising a frame (11), a second thread passing member (9) and a looper (10), wherein the mounting frame (2) of the bottom line tension control mechanism is fixedly connected with the frame (11), the looper (10) is arranged on the outgoing line side of a thread-making frame (4) of the bottom line tension control mechanism, and the second thread passing member (9) is arranged between the looper (10) and the thread-making frame (4) and is fixedly connected with the frame (11).