阅读说明：本技术 一种适应高转速的针杆驱动结构 (Needle bar driving structure suitable for high rotating speed ) 是由 陈天池 张汉苗 郑邓飞 楼凯 于 2020-12-25 设计创作，主要内容包括：一种适应高转速的针杆驱动结构,包括机壳和主轴,还包括轮轴传动组件、转动块、杠杆组件、导向柱和针杆驱动座,所述主轴与所述轮轴传动组件传动连接,所述轮轴传动组件、所述杠杆组件、所述导向柱均与所述机壳固定连接,所述杠杆组件具有一支点端部、一自由端部和位于该两者之间的使动部；所述杠杆组件的使动部与所述转动块之间通过连杆一传动连接,所述转动块与所述轮轴传动组件固定连接而由所述轮轴传动组件带动转动；所述杠杆组件的自由端部与所述针杆驱动座之间通过连杆二传动连接,所述针杆驱动座滑动连接在所述导向柱上而可沿着所述导向柱竖直升降。本发明采用新的结构来取代老式的凸轮与连杆机构,传动同步性和稳定性较高,绣品质量较好。(A needle bar driving structure adapting to high rotating speed comprises a machine shell and a main shaft, and further comprises a wheel shaft transmission assembly, a rotating block, a lever assembly, a guide post and a needle bar driving seat, wherein the main shaft is in transmission connection with the wheel shaft transmission assembly; the moving part of the lever assembly is in transmission connection with the rotating block through a connecting rod, and the rotating block is fixedly connected with the wheel axle transmission assembly and driven to rotate by the wheel axle transmission assembly; the free end part of the lever component is in transmission connection with the needle rod driving seat through a connecting rod II, and the needle rod driving seat is connected to the guide post in a sliding mode and can vertically lift along the guide post. The invention adopts a new structure to replace the old cam and link mechanism, has higher transmission synchronism and stability and better embroidery quality.)

1. A needle bar driving structure adapting to high rotating speed comprises a machine shell (1) and a main shaft, and is characterized in that: the needle bar driving mechanism is characterized by further comprising a wheel shaft transmission assembly (2), a rotating block (3), a lever assembly (4), a guide post (5) and a needle bar driving seat (6), wherein the main shaft is in transmission connection with the wheel shaft transmission assembly (2), the lever assembly (4) and the guide post (5) are fixedly connected with the machine shell (1), and the lever assembly (4) is provided with a fulcrum end part, a free end part and a moving part positioned between the fulcrum end part and the free end part; the moving part of the lever component (4) is in transmission connection with the rotating block (3) through a first connecting rod (7), and the rotating block (3) is fixedly connected with the wheel axle transmission component (2) and driven by the wheel axle transmission component (2) to rotate; the free end part of the lever component (4) is in transmission connection with the needle rod driving seat (6) through a second connecting rod (8), and the needle rod driving seat (6) is in sliding connection with the guide post (5) and can vertically lift along the guide post (5).

2. A needle bar drive structure adapted to a high rotational speed according to claim 1, wherein: the lever assembly (4) is bilaterally symmetrical about a central sectioning plane; or the whole composed of the lever component (4), the first connecting rod (7), the second connecting rod (8) and the needle rod driving seat (6) is bilaterally symmetrical about the central sectional plane.

3. A needle bar drive structure adapted to a high rotational speed according to claim 1, wherein: the lever component (4) comprises two connecting plates (41), a first positioning connecting rod (42), a second positioning connecting rod (42 ') and a third positioning connecting rod (42' ') are connected between the two connecting plates (41), and the second positioning connecting rod (42') positioned in the middle is used as the moving part and is rotationally connected with the first connecting rod (7); the positioning connecting rod three (42 ' ') positioned at the front side of the positioning connecting rod two (42 ') is used as the free end part and is in rotating connection with the connecting rod two (8); the first positioning connecting rod (42) positioned at the rear side of the second positioning connecting rod (42') serves as the end part of the fulcrum and is rotatably connected with a positioning connecting part in the machine shell (1) or is rotatably connected with a positioning connecting block fixedly connected in the machine shell (1).

4. A needle bar drive structure adapted to a high rotational speed according to claim 3, wherein: a reinforcing support rod (43) is connected between the two connecting sheets (41).

5. A needle bar drive structure adapted to a high rotational speed according to claim 3, wherein: the guide column (5) penetrates between the two connecting pieces (41).

6. A needle bar drive structure adapted to a high rotational speed according to claim 1, wherein: the rotating block (3) comprises a counterweight part (31) and a connecting part (32), and a first connecting part (321) for connecting the wheel axle transmission assembly (2) and a second connecting part (322) for connecting the first connecting rod (7) are arranged on the connecting part (32); the counterweight part (31) is used for keeping the mass center corresponding to the rotating block (3) and the needle bar driving seat (6) relatively motionless or minimizing the variation range when the rotating block (3) and the needle bar driving seat (6) are considered as a whole in the process of synchronously moving the rotating block (3) and the needle bar driving seat (6).

7. A needle bar drive structure adapted to a high rotational speed according to claim 1 or 6, wherein: the needle rod driving seat (6) is provided with a guide sleeve hole (61) for sleeving the guide post (5), a connecting rod connecting part (62) for connecting the second connecting rod (8) and a needle rod butt joint part (63) for connecting and driving the needle rod.

8. A needle bar drive structure adapted to a high rotational speed according to claim 7, wherein: the needle bar driving seat (6) is also provided with an outer wall opening for exposing partial area of the guide sleeve hole (61).

9. A needle bar drive structure adapted to a high rotational speed according to claim 1, wherein: the wheel shaft transmission assembly (2) comprises a bearing seat (21), a first transmission shaft (22), a second transmission shaft (23), a first gear (24) and a second gear (25), the bearing seat (21) is fixedly connected to the machine shell (1), the main shaft is in transmission connection with the first transmission shaft (22), the first transmission shaft (22) and the second transmission shaft (23) are respectively connected with the bearing seat (21), the first gear (24) is fixedly connected to the first transmission shaft (22), the second gear (25) is fixedly connected to the second transmission shaft (23), and the first gear (24) is in meshing connection with the second gear (25); the rotating block (3) is fixedly connected to the second transmission shaft (23).

10. A needle bar drive structure adapted to a high rotational speed according to claim 9, wherein: the first gear (24) and the second gear (25) respectively comprise a metal part and a plastic part, the plastic part is formed outside the metal part in an injection molding mode, tooth grooves are formed in the plastic part, the metal part of the first gear (24) is fixedly connected to the first transmission shaft (22), and the metal part of the second gear (25) is fixedly connected to the second transmission shaft (23).

Technical Field

The invention relates to the technical field of embroidery machines, in particular to a needle bar driving structure suitable for high rotating speed.

Background

The stability of the movement of the needle bar of the computer embroidery machine directly influences the quality of embroidery products of the embroidery machine, and how to realize high-precision and high-quality embroidery of the needle bar of the embroidery machine under the state of high-speed operation (the rotating speed of a main shaft is 1200r/min or more can be considered as high rotating speed) is always the research direction of researchers in the embroidery machine industry. The needle bar driving mechanism of the prior embroidery machine generally has the following problems: a single-convex double-drive embroidery machine head and an embroidery machine as disclosed in the patent document CN201921496463.6, comprising a first driving component, a second driving component, a driving shaft, a housing, a transmission shaft, a cam mechanism, a needle bar, a presser foot component, a connecting component and a guiding component, wherein the presser foot connecting rod and the needle bar connecting rod are driven by a grooved cam, so as to drive the presser foot and the needle bar respectively, i.e. the cam is driven by the main shaft directly, one end of the connecting rod structure moves along the track groove on the cam and the other end is connected with the needle bar or the presser foot, and a plurality of connecting rods are often needed to be arranged and hinged with each other, although such cam and connecting rod structure is old, the arrangement is simple, the cost is low, the use is common, and the following defects are mainly: 1. the grooved cam and the connecting rod are in contact guidance and are not directly and fixedly connected, so that the phenomenon of transmission delay or instability easily exists in a high-speed running state, and the embroidery quality is influenced; 2. the front and the back of the connecting rods are hinged end to end, so that the structural span is long, the structure is unstable, and the mounting space is occupied; 3. the front and back end-to-end hinged mode of the connecting rods enables the whole connecting rod structure to be an asymmetric structure, the connection point of the connecting rod structure and the needle bar is also the single side of the last connecting rod, the conduction stress is unbalanced, the structure is unstable, and the penetrating force of the needle bar is insufficient; 4. the main shaft is directly connected with the cam, and the main shaft bears a large load and is easy to damage.

Disclosure of Invention

The invention aims to provide a needle bar driving structure adaptive to high rotating speed, and solves the problems of old structure, low transmission precision, poor structure and transmission stability and difficulty in adapting to high rotating speed operation in the traditional structure.

The specific technical scheme of the invention is as follows: a needle bar driving structure adapting to high rotating speed comprises a machine shell and a main shaft, and further comprises a wheel shaft transmission assembly, a rotating block, a lever assembly, a guide post and a needle bar driving seat, wherein the main shaft is in transmission connection with the wheel shaft transmission assembly; the moving part of the lever assembly is in transmission connection with the rotating block through a connecting rod, and the rotating block is fixedly connected with the wheel axle transmission assembly and driven to rotate by the wheel axle transmission assembly; the free end part of the lever component is in transmission connection with the needle rod driving seat through a connecting rod II, and the needle rod driving seat is connected to the guide post in a sliding mode and can vertically lift along the guide post.

Preferably, the lever assembly is bilaterally symmetrical about a central sectional plane thereof; or the whole body formed by the lever component, the first connecting rod, the second connecting rod and the needle rod driving seat is symmetrical left and right about the central sectional plane.

Preferably, the lever assembly comprises two connecting pieces, a first positioning connecting rod, a second positioning connecting rod and a third positioning connecting rod are connected between the two connecting pieces, and the second positioning connecting rod positioned in the middle is used as the moving part and is rotationally connected with one connecting rod; the positioning connecting rod III positioned on the front side of the positioning connecting rod II is used as the free end part and is rotationally connected with the connecting rod II; the first positioning connecting rod positioned at the rear side of the second positioning connecting rod is used as the end part of the fulcrum and is rotatably connected with a positioning connecting part in the shell, or is rotatably connected with a positioning connecting block fixedly connected in the shell.

Preferably, a reinforcing support rod is connected between the two connecting sheets.

Preferably, the guide post passes between the two connecting pieces.

Preferably, the rotating block comprises a counterweight part and a connecting part, and the connecting part is provided with a first connecting part for connecting the wheel axle transmission assembly and a second connecting part for connecting the first connecting rod; the counterweight part is used for keeping the corresponding mass center of the rotating block and the needle rod driving seat relatively motionless or minimizing the variation range of the rotating block and the needle rod driving seat when the rotating block and the needle rod driving seat are considered as a whole in the process of synchronous movement of the rotating block and the needle rod driving seat.

Preferably, the needle rod driving seat is provided with a guide sleeve hole for sleeving the guide post, a connecting rod connecting part for connecting the second connecting rod and a needle rod butt joint part for connecting and driving the needle rod.

Preferably, the needle bar driving seat is further provided with an outer wall opening for exposing a partial region of the guide sleeve hole.

Preferably, a lubricating cavity is arranged on the needle rod driving seat, a lubricating piece is arranged in the lubricating cavity, and a communicating oil path exists between the guide sleeve hole and/or the connecting rod connecting part and the lubricating cavity.

Preferably, the wheel shaft transmission assembly comprises a bearing seat, a first transmission shaft, a second transmission shaft, a first gear and a second gear, the bearing seat is fixedly connected to the machine shell, the main shaft is in transmission connection with the transmission shaft, the first transmission shaft and the second transmission shaft are respectively connected with the bearing seat, the first gear is fixedly connected to the first transmission shaft, the second gear is fixedly connected to the second transmission shaft, and the first gear is in meshing connection with the second gear; the rotating block is fixedly connected to the second transmission shaft.

Preferably, the first gear and the second gear respectively comprise a metal shaping part and a plastic shaping part, the plastic shaping part is formed outside the metal shaping part in an injection molding mode, a tooth groove is formed in the plastic shaping part, the metal shaping part of the first gear is fixedly connected to the first transmission shaft, and the metal shaping part of the second gear is fixedly connected to the second transmission shaft.

The technical advantages of the invention are as follows:

1. compared with the traditional mode that the main shaft directly drives the cam, the mode that the wheel shaft transmission assembly can bear larger load is higher in transmission precision and transmission efficiency and low in noise;

2. the rotating block is rotatably connected with the first connecting rod, so that the transmission synchronism is high, the operation is stable, and the mechanical response is timely;

3. the first connecting rod, the lever assembly and the needle rod connecting assembly replace an old connecting rod structure, the transmission stroke is short, the operation is stable, and the installation space is flexible;

4. the transmission structure is provided with symmetrical parts, the transmission stress is balanced, the operation is stable, and the penetration force of the needle rod is higher after the needle rod is driven;

in conclusion, the device helps to obtain high-quality embroidery products, and is worthy of being popularized and used in the field.

Drawings

FIG. 1 is a schematic overall structural view (assembly view) of an embodiment of the present invention;

FIG. 2 is a schematic diagram of the overall structure of an embodiment of the present invention (with the components separated from the housing);

FIG. 3 is a schematic structural view of an axle drive assembly according to an embodiment of the present invention;

FIG. 4 is a schematic structural view of the lever assembly, the rotating block and the needle bar driving seat according to the embodiment of the present invention;

FIG. 5 is a schematic structural view of a lever assembly according to an embodiment of the present invention;

FIG. 6 is a schematic structural diagram of a rotating block according to an embodiment of the present invention;

FIG. 7 is a schematic structural view of a needle bar driving seat according to an embodiment of the present invention;

the names of the parts corresponding to the numbers in the figure are respectively: 1-a machine shell, 2-an axle transmission component, 21-a bearing seat, 22-a transmission shaft I, 23-a transmission shaft II, 24-a gear I, 25-a gear II, 3-a rotating block, 31-a counterweight part, 32-a connecting part, 321-a first connecting part, 322-a second connecting part, 4-a lever component, 41-a connecting piece, 42-a positioning connecting rod, 43-a reinforcing supporting rod, 5-a guide post, 6-a needle rod driving seat, 61-a guide sleeve hole, 62-a connecting rod connecting part, 63-a needle rod butt joint part, 64-an outer wall opening, 65-a lubricating cavity, 7-a connecting rod I and 8-a connecting rod II.

Detailed Description

The invention will be further illustrated by means of specific embodiments in the following description with reference to the accompanying drawings:

referring to fig. 1 and 2, an embodiment of a needle bar driving structure adapted to high rotation speed includes a housing 1 and a main shaft, as well as a wheel shaft transmission assembly 2, a rotation block 3, a lever assembly 4, a guide post 5 and a needle bar driving seat 6, wherein a supporting bearing seat is arranged at the top of the housing 1, the main shaft is connected to the supporting bearing seat, the main shaft is in transmission connection with the wheel shaft transmission assembly 2, the lever assembly 4 and the guide post 5 are all fixedly connected to the housing 1, and the lever assembly 4 has a fulcrum end, a free end and a moving part located between the fulcrum end and the free end; the moving part of the lever component 4 is in transmission connection with the rotating block 3 through a first connecting rod 7, and the rotating block 3 is fixedly connected with the wheel axle transmission component 2 and driven to rotate by the wheel axle transmission component 2; the free end part of the lever component 4 is in transmission connection with the needle rod driving seat 6 through a second connecting rod 8, and the needle rod driving seat 6 is in sliding connection with the guide post 5 and can vertically lift along the guide post 5.

In the present embodiment, the whole body formed by the lever assembly 4, the first connecting rod 7, the second connecting rod 8 and the needle bar driving seat 6 is a bilateral symmetry structure about the longitudinal central sectional plane, so the design is because after the applicant researches and practices, the traditional old connecting rod transmission structure is a completely asymmetric structure, the driving force is continuously deflected in the transmission process rather than being transmitted along the structure central line, the local stress is too large, the transmission is unstable, the components are easy to damage, the final movement of the needle bar is not stable, and the penetrating force is insufficient, and the adverse effects can be weakened or avoided by designing as many structural parts of the transmission structure as possible to be symmetrical, so the design with such high symmetry is provided in the present embodiment, in some embodiments, for other reasons, such as convenience for assembling arrangement of components in other housings 1 and the like, alternatively, the lever assembly 4 may be designed to be symmetrical, which, although compromised in symmetry, still provides a stable and balanced transmission over conventional old-fashioned linkage arrangements, each of which will be described in greater detail below.

Regarding the wheel axle transmission assembly 2, see fig. 3, it includes a bearing seat 21, a first transmission shaft 22, a second transmission shaft 23, a first gear 24 and a second gear 25, the bearing seat 21 is fixedly connected to the housing 1 (a connecting bearing corresponding to the two transmission shafts is provided in the bearing seat 21), the first transmission shaft 22 and the second transmission shaft 23 are respectively connected to the bearing seat 21, the main shaft is in transmission connection with the first transmission shaft 22, the first gear 24 is fixedly connected to the first transmission shaft 22, the second gear 25 is fixedly connected to the second transmission shaft 23, and the first gear 24 is in engagement connection with the second gear 25; the rotating block 3 is fixedly connected to the second transmission shaft 23, namely the first transmission shaft 22 is driven by the main shaft to rotate (the simplest mode is that a belt wheel arranged on the main shaft and a belt wheel arranged on the first transmission shaft 22 are connected through a belt in a transmission mode), and the first transmission shaft 22 drives the second transmission shaft 23 to rotate and the second transmission shaft 23 drives the rotating block 3 to rotate due to the fact that the first gear 24 is meshed with the second gear 25. The first gear 24 and the second gear 25 respectively comprise a metal part and a plastic part, the plastic part is formed outside the metal part in an injection molding mode, tooth grooves are formed in the plastic part, the metal part of the first gear 24 is fixedly connected to the first transmission shaft 22, the metal part of the second gear 25 is fixedly connected to the second transmission shaft 23, and in the embodiment, the metal part and the shaft are integrally formed. The first gear 24 and the second gear 25 are designed in a split type mode different from a traditional gear, because the traditional gear made of all-metal materials is limited by a processing technology, errors are large, transmission gaps easily exist during gear meshing transmission, transmission is unstable, embroidery processing and quality are affected, a plastic part is easy to process, controllability on the gap errors is good, noise during transmission is greatly reduced, cost is reduced, the metal part and a shaft are convenient and firm to form, and the plastic part and the metal part are formed in the same mode, so that the first gear 24 and the second gear 25 in the scheme are completely different from and better than the traditional gear in design, transmission precision can be obviously improved, and embroidery quality is effectively improved.

Referring to fig. 4 and 5, the lever assembly 4 includes two connecting plates 41, the two connecting plates 41 are identical and symmetrical in shape, and a first positioning connecting rod 42, a second positioning connecting rod 42 'and a third positioning connecting rod 42' are connected between the two connecting plates 41, and in the illustration, the first positioning connecting rod 42, the third positioning connecting rod 42 'and the second positioning connecting rod 42' are sequentially arranged between the tail ends, the head ends and the middle sections of the two connecting plates 41 (of course, more similar positioning connecting rods may be arranged as required). The first positioning connecting rod 42 located between the tail ends of the connecting pieces 41 is used as a fulcrum end and is rotatably connected with a positioning connecting block, and the positioning connecting block is fixedly connected with the inner wall of the casing 1. The second positioning connecting rod 42' positioned between the middle sections of the connecting sheets 41 is used as a movable part and is rotatably connected with the lower end of the first connecting rod 7. The third positioning connecting rod 42' between the head ends of the connecting pieces 41 is rotatably connected to the lower end of the second connecting rod 8 as a free end.

The design of two connecting pieces 41, firstly because the needs of symmetrical structure let the point of conduction atress balance on central section and improve transmission stability, secondly because the slice connection structure after improving like this, compare in traditional connecting rod structure, can subtract heavy, can reduce air resistance again, the noise of moving simultaneously is also relatively littleer. In this embodiment, the connection points of the connection pieces 41 corresponding to the three positioning connection rods are the head, the tail and the center, so that the connection is more balanced and stable. A reinforcing support bar 43 is also connected between the two connecting plates 41 and is disposed between the adjacent positioning connecting rods in order to further ensure sufficient strength of the connecting plates 41 in the case of high-speed operation. The guide post 5 passes through the spacing space between the two connecting sheets 41 near the head end, so that the assembly stations of the guide post 5 and the lever assembly 4 in the machine shell 1 are optimized on the basis of enabling the structure of the lever assembly 4 to be large enough to have higher structural strength and better transmission stability, and meanwhile, the guide post 5 is arranged in such a way that the guide post and the lever assembly 4 can also be in a symmetrical structure integrally.

Regarding the rotating block 3, see fig. 6, the rotating block 3 includes a counterweight portion 31 and a connecting portion 32, in this embodiment, the rotating block 3 is designed as a special-shaped block similar to a fan in shape as shown in the figure, a fan body portion is the counterweight portion 31, a fan handle portion is the connecting portion 32, and the connecting portion 32 is provided with a first connecting portion 321 for connecting the wheel axle transmission assembly 2, i.e., the transmission shaft two 23, and a second connecting portion 322 for connecting the upper end of the connecting rod one 7, which are in the form of connecting holes in the figure. The hole of the first connecting portion 321 is in the form of a broken seam, the broken seam extends out of the counterweight portion 31, the counterweight portion 31 is provided with a fastening screw hole and a fastening screw in a matching manner, and the second transmission shaft 23 is held by the first connecting portion 321. The second connecting portion 322 is rotatably connected to the first connecting rod 7 by a conventional bearing and a connecting pin.

The counterweight part 31 is used for keeping the mass center corresponding to the rotating block 3 and the needle bar driving seat 6 relatively motionless or within a relatively minimum variation range when the rotating block 3 and the needle bar driving seat 6 are regarded as a whole in the process of synchronous movement of the rotating block 3 and the needle bar driving seat 6, so that the rotating block 3 and the needle bar driving seat 6 can be kept in a dynamic balance state as far as possible during operation, particularly under the condition of high-speed movement, the phenomenon of structural jitter during operation is reduced, the transmission is more stable, the response is more timely, and the parts are less prone to damage. The corresponding operational behavior can be described as follows, namely, when the needle bar drive holder 6 moves to the lowest position along the guide post 5, the weight portion 31 rotates to the position of the side farthest from the needle bar drive holder 6; when the needle bar drive holder 6 moves to the highest position along the guide post 5, the weight portion 31 rotates to a position on the nearest side of the needle bar drive holder 6. Of course, it is possible that the aforementioned two relative rotational positions are the same (e.g., when the needle bar drive holder 6 is moved to the lowest or highest position, the weight portion 31 may be rotated to the mentioned position near the farthest or closest position to the needle bar drive holder 6), the mass, distance, and the predetermined variation of the center of mass of the actual follower block 3 and the needle bar drive holder 6 are taken as a whole, and the corresponding operating performance may be determined by a plurality of preliminary tests.

The rotating block 3 is different from a cam in the traditional structure, the rotating block 3 is rotationally connected with the connecting rod I7 to drive the connecting rod I7 to do reciprocating motion, and the driving synchronism is obviously superior to the driving form of the cam in the traditional structure, because the connecting rod I7 does not extend into a groove of the cam and moves along the groove of the cam, a contact gap does not exist, and the conditions of transmission lag and unstable transmission are not easy to occur even in a high-speed operation state. In addition, the main shaft is not directly connected with the rotating block 3, but the wheel shaft transmission assembly 2 is arranged between the main shaft and the rotating block, compared with the mode that the main shaft is directly connected with the driving cam in the traditional structure, the load of the main shaft can be effectively reduced through the structural design of the main shaft, and the wheel shaft transmission assembly 2 is high in transmission precision and transmission efficiency and low in noise due to the gear transmission mode.

Regarding the needle bar driving seat 6, see fig. 7, the needle bar driving seat 6 is provided with a guide sleeve hole 61 for sleeving the guide post 5, a connecting rod connecting part 62 for connecting the second connecting rod 8 and a needle bar butting part 63 for connecting and driving the needle bar. In this embodiment, the needle bar driving holder 6 itself is also of a symmetrical structure, and the guide sleeve hole 61 has a central cross section coinciding with the central cross section of the needle bar driving holder 6. The connecting rod connecting portion 62 is a connecting cavity formed in the needle bar driving holder 6, and the central cross section of the connecting cavity is also coincident with the central cross section of the needle bar driving holder 6. The needle bar butt joint part 63 is a horizontal through clamping groove which is open towards the side of the needle bar side, because the needle bar frame is in sliding connection with the machine shell 1, the needle bar is also provided with a needle bar driving block, the needle bar driving block is provided with a butt joint matched with the clamping groove, and the needle bar driving block can horizontally slide into the clamping groove when moving horizontally along with the needle bar frame. The central section of the needle bar abutment 63 is also symmetrical with the central section of the needle bar driving holder 6. The needle bar driving holder 6 is further provided with an outer wall opening 64 for exposing a partial region of the guide sleeve hole 61 to the outside, so as to reduce the contact surface between the inner wall of the guide sleeve hole 61 and the guide post 5 to reduce frictional resistance and make the elevation of the needle bar driving holder 6 smoother. The top of the needle bar driving seat 6 is also provided with a lubricating cavity 65, a lubricating piece such as felt is arranged in the lubricating cavity 65, and the guide sleeve hole 61 and the connecting rod connecting part 62 are communicated with the lubricating cavity 65.

It is worth mentioning that in practical products, the "symmetry" referred to above cannot be strictly considered as "symmetry" in an absolute sense, for example, the connecting pieces 41 may have some minor modifications (e.g. a notch or a protrusion or an opening, etc.) at some place due to manufacturing or assembly interference or connection requirements, so that the two connecting pieces 41 are not absolutely symmetrical, but should be considered as a symmetrical design in view of the overall structure, and in itself still be optimized for and with the aforementioned symmetrical design.

It will be appreciated by persons skilled in the art that the embodiments of the invention described above and shown in the drawings are given by way of example only and are not limiting of the invention. The objects of the present invention have been fully and effectively accomplished. The functional and structural principles of the present invention have been shown and described in the embodiments, and any variations or modifications may be made to the embodiments of the present invention without departing from the principles.