Closed needle bar oil-proof structure and sewing machine

Abstract

The utility model discloses a closed needle bar oil-proof structure and a sewing machine in the technical field of sewing machines. The closed needle bar oil-proof structure comprises a machine shell. The lower lining is installed on the machine shell, and a grease storage groove is formed in the inner circumferential face of the lower lining; the needle rod can be arranged in the lower lining in a penetrating mode in an axial moving mode, and the radial size of the grease storage groove is larger than that of the needle rod; the upper oil seal is arranged on the lower bush in a sleeving mode, the bottom end of the upper oil seal is fixedly connected with the top end of the lower bush, and the top end of the upper oil seal is connected with the needle rod in a sealed mode; the lower oil seal is arranged on the lower lining in a sleeved mode, the top end of the lower oil seal is fixedly connected with the bottom end of the lower lining, and the bottom end of the lower oil seal is connected with the needle rod in a sealed mode. The needle rod lubricating device not only plays a role in lubricating the needle rod, but also can prevent lubricating oil in the machine head from seeping out, has the effects of preventing thread clamping and dust, and has the advantages of being simple in structure and convenient to install and maintain.

Description

Technical Field

[0001] The utility model relates to the technical field of sewing machines, in particular to a closed needle bar oil-proof structure and a sewing machine. Background Art

[0002] The sewing machine's piercing mechanism is a mechanism that drives the needle bar to move up and down with the needle at high speed. During the sewing process, the needle moves up and down relative to the lower bushing, which causes easy wear between the needle bar and the lower bushing. In order to reduce wear, lubricating oil needs to be applied between the needle bar and the lower bushing for lubrication. However, during the sewing process, the lubricating oil will also seep through the gap between the needle bar and the lower bushing and contaminate the sewing material.

[0003] like Figure 6 As shown, in order to prevent the lubricating oil from leaking from the gap between the needle rod and the lower bushing, technicians in this field generally use a spring to tighten a lower oil seal at the bottom end of the lower bushing, and realize a dynamic sealing connection between the lower oil seal and the needle rod through the elastic contact between the bottom lip of the lower oil seal and the needle rod.

[0004] In actual production activities, after the sewing machine has been used for a period of time, lubricating oil overflows frequently between the lower oil seal and the lower bushing due to the uneven matching surface of the lower oil seal and the lower bushing, or the loose matching of the lower oil seal and the lower bushing. At this time, it is necessary to remove the lower oil seal and clean the lubricating oil, which not only causes the sewing operation to be interrupted, but also may cause the lubricating oil to contaminate the sewing material. In addition, technical personnel in this field have also adopted oil-free design, grease lubrication and active oil suction needle bar lubrication methods, but there are generally problems of complex structure and high cost.

[0005] Therefore, how to prevent the lubricating oil from overflowing from between the lower oil seal and the lower bushing has become a technical problem that needs to be solved urgently by those skilled in the art. Utility Model Content

[0006] In view of this, the purpose of the utility model is to provide a closed needle bar oil-proof structure to solve the technical problem that the existing needle bar oil-proof structure is prone to leaking lubricating oil.

[0007] The technical solution adopted by the utility model is: a closed needle bar oil-proof structure, comprising:

[0008] chassis;

[0009] A lower bushing, the lower bushing is mounted on the casing, and a grease storage groove is formed on the inner circumferential surface of the lower bushing;

[0010] A needle rod, the needle rod is axially movable and penetrates the lower bushing, and the radial dimension of the fat storage groove is larger than the radial dimension of the needle rod;

[0011] Upper oil seal, the upper oil seal is sleeved on the lower bushing, and the bottom end of the upper oil seal is fixedly connected to the top end of the lower bushing, and the top end of the upper oil seal is sealingly connected to the needle rod;

[0012] Lower oil seal, the lower oil seal is sleeved on the lower bushing, and the top end of the lower oil seal is fixedly connected to the bottom end of the lower bushing, and the bottom end of the lower oil seal is sealingly connected to the needle rod.

[0013] Preferably, two lower elastic lips are connected to the bottom end of the lower oil seal, the lower elastic lips are located directly below the lower bushing, the upper lower elastic lip extends obliquely upward and elastically abuts against the needle rod, the lower lower elastic lip extends obliquely downward and elastically abuts against the needle rod, and the two lower elastic lips and the needle rod enclose a lower annular sealing cavity, and the lower annular sealing cavity is filled with lubricating grease.

[0014] Preferably, the lower oil seal includes a lower axial part and a lower radial part, the top end of the lower axial part is detachably and fixedly connected to the bottom end of the lower bushing, the outer peripheral side of the lower radial part is fixedly connected to the bottom end of the lower axial part, and the inner peripheral side of the lower radial part is fixedly connected to two lower elastic lips.

[0015] Preferably, two upper elastic lips are connected to the top end of the upper oil seal, the upper elastic lips are located directly above the lower bushing, the upper upper elastic lip extends obliquely upward and elastically abuts against the needle rod, the lower upper elastic lip extends obliquely downward and elastically abuts against the needle rod, and the two upper elastic lips and the needle rod enclose an upper annular sealing cavity, and the upper annular sealing cavity is filled with lubricating grease.

[0016] Preferably, the upper oil seal includes an upper axial part and an upper radial part, the bottom end of the upper axial part is detachably and fixedly connected to the top end of the lower bushing, the outer peripheral side of the upper radial part is fixedly connected to the bottom end of the upper axial part, and the inner peripheral side of the upper radial part is fixedly connected to two upper elastic lips.

[0017] Preferably, an upper connection groove is provided on the outer circumferential surface of the top end of the lower bushing, an upper connection protrusion is formed on the inner circumferential surface of the bottom end of the upper oil seal, and the upper connection protrusion is clamped in the upper connection groove; a lower connection groove is provided on the outer circumferential surface of the bottom end of the lower bushing, a lower connection protrusion is formed on the inner circumferential surface of the top end of the lower oil seal, and the lower connection protrusion is clamped in the lower connection groove.

[0018] Preferably, an upper tightening groove is formed on the outer circumferential surface of the upper oil seal, the upper connection protrusion corresponds to the upper tightening groove, and an upper tightening spring for tightening the upper oil seal is accommodated in the upper tightening groove; a lower tightening groove is formed on the outer circumferential surface of the lower oil seal, the lower connection protrusion corresponds to the lower tightening groove, and a lower tightening spring for tightening the lower oil seal is accommodated in the lower tightening groove.

[0019] Preferably, the grease storage groove is an annular groove.

[0020] Preferably, an external oil injection hole is formed on the machine shell, an internal oil injection hole communicating with the grease storage groove is formed on the lower bushing, and the external oil injection hole communicates with the internal oil injection hole.

[0021] The second object of the present utility model is to provide a sewing machine, which includes the above-mentioned closed type needle bar oil-proof structure.

[0022] The beneficial effects of the present utility model:

[0023] In the present utility model, a grease storage groove is formed on the inner circumferential surface of the lower bushing. Grease is stored between the lower bushing and the needle bar through the grease storage groove, realizing grease lubrication between the needle bar and the lower bushing and avoiding the use of lubricating oil. At both ends of the lower bushing of the present utility model, an upper oil seal and a lower oil seal are respectively fixedly connected. Through the elastic sealing connection between the upper oil seal and the needle bar, the lubricating oil inside the machine head can be prevented from flowing into the gap between the needle bar and the lower bushing. Through the elastic sealing connection between the lower oil seal and the needle bar, grease leakage can be effectively avoided. In this way, not only is the lubrication between the needle bar and the lower bushing realized, the occurrence of lubricating oil overflow is avoided, and the normal progress of sewing operations is ensured, but also it has the advantages of simple structure, convenient installation and easy maintenance. Description of the Drawings

[0024] Figure 1 is a schematic structural diagram of the closed type needle bar oil-proof structure of the present utility model;

[0025] Figure 2 is a three-dimensional schematic diagram of the closed type needle bar oil-proof structure of the present utility model;

[0026] Figure 3 is a schematic structural diagram of the lower bushing;

[0027] Figure 4 is a schematic structural diagram of the upper oil seal;

[0028] Figure 5 is a schematic structural diagram of the lower oil seal;

[0029] Figure 6 is a schematic structural diagram of the existing needle bar oil-proof structure.

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

[0031] 10. Machine shell;

[0032] 11. External oil injection hole;

[0033] 20. Lower bushing;

[0034] 21. Fat storage groove; 22. Upper connection groove; 23. Lower connection groove; 24. Inner oil injection hole;

[0035] 30. Needle rod;

[0036] 40. Upper oil seal;

[0037] 41. Upper elastic lip; 42. Upper annular seal cavity; 43. Upper axial part; 44. Upper radial part; 45. Upper connection projection; 46. Upper tightening groove; 47. Upper limit groove;

[0038] 50. Lower oil seal;

[0039] 51. Lower elastic lip; 52. Lower annular seal cavity; 53. Lower axial part; 54. Lower radial part; 55. Lower connection projection; 56. Lower tightening groove; 57. Lower limit groove;

[0040] 60. L-shaped rigid skeleton;

[0041] 70. Upper tightening spring;

[0042] 80. Lower tightening spring. Specific embodiments

[0043] The following further elaborates on the specific embodiments of the present utility model in conjunction with the accompanying drawings. These embodiments are only for explaining the present utility model and not for limiting it.

[0044] In the description of the present utility model, it should be noted that the orientation or positional relationships indicated by the terms "center", "longitudinal", "transverse", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", etc. are based on the orientation or positional relationships shown in the accompanying drawings. They are only for facilitating the description of the present utility model and simplifying the description, rather than indicating or implying that the device or element referred to must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be construed as a limitation to the present utility model. In addition, the terms "first" and "second" are only used for descriptive purposes and cannot be construed as indicating or implying relative importance.

[0045] In the description of the present utility model, it should be noted that unless otherwise clearly specified and defined, the terms "installation", "connection", and "coupling" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be directly connected or indirectly connected through an intermediate medium, and it can be the communication inside two elements. For those of ordinary skill in the art, the specific meanings of the above terms in the present utility model can be understood according to specific circumstances.

[0046] In addition, in the description of the present utility model, unless otherwise specified, the meaning of "a plurality of" is two or more.

[0047] An embodiment is as follows Figures 1-5 As shown, a closed type needle bar oil-proof structure includes: a machine housing 10, a lower bushing 20, a needle bar 30, an upper oil seal 40, and a lower oil seal 50; the lower bushing 20 is installed on the machine housing 10, and a grease storage groove 21 is formed on the inner circumferential surface of the lower bushing 20; the needle bar 30 is axially movable through the lower bushing 20, and the radial dimension of the grease storage groove 21 is greater than the radial dimension of the needle bar 30; the upper oil seal 40 is sleeved on the lower bushing 20, and the bottom end of the upper oil seal 40 is fixedly connected to the top end of the lower bushing 20, and the top end of the upper oil seal 40 is elastically abutted and sealed with the needle bar 30; the lower oil seal 50 is sleeved on the lower bushing 20, and the top end of the lower oil seal 50 is fixedly connected to the bottom end of the lower bushing 20, and the bottom end of the lower oil seal 50 is elastically abutted and sealed with the needle bar 30.

[0048] In the present application, a grease storage groove 21 is formed on the inner circumferential surface of the lower bushing 20, and lubricating grease is stored between the lower bushing 20 and the needle bar 30 through the grease storage groove 21, realizing grease lubrication between the needle bar 30 and the lower bushing 20 and avoiding the use of lubricating oil; in the present application, an upper oil seal 40 and a lower oil seal 50 are respectively fixedly connected to both ends of the lower bushing 20. Through the elastic sealing connection between the upper oil seal 40 and the needle bar 30, the lubricating oil inside the machine head can be prevented from flowing into the gap between the needle bar 30 and the lower bushing 20. Through the elastic sealing connection between the lower oil seal 50 and the needle bar 30, grease leakage can be effectively avoided. In this way, not only is the lubrication between the needle bar 30 and the lower bushing 20 realized, the occurrence of lubricating oil overflow is avoided, and the normal progress of sewing operations is ensured, but also it has the advantages of simple structure, convenient installation, and easy maintenance.

[0049] Specific embodiment 1 is as follows Figures 1-5 As shown, a closed type needle bar oil-proof structure includes: a machine housing 10, a lower bushing 20, a needle bar 30, an upper oil seal 40, and a lower oil seal 50; the lower bushing 20 is fixedly installed in the installation hole of the machine housing 10 in the vertical direction, and a grease storage groove 21 is formed on the inner circumferential surface of the lower bushing 20. The needle bar 30 is axially movable through the lower bushing 20, that is, the lower bushing 20 is coaxially sleeved outside the needle bar 30, and the needle bar 30 and the lower bushing 20 can axially move relative to each other. The radial dimension of the grease storage groove 21 is greater than the radial dimension of the needle bar 30 to store lubricating grease between the needle bar 30 and the lower bushing 20 and realize grease lubrication between the needle bar 30 and the lower bushing 20.

[0050] The upper oil seal 40 is sleeved on the lower bushing 20, and the bottom end of the upper oil seal 40 is detachably fixedly connected to the top end of the lower bushing 20, and the top end of the upper oil seal 40 is sealedly connected to the needle rod 30, that is, the inner side of the top end of the upper oil seal 40 is fixedly connected with an upper elastic lip 41, and the inner end of the upper elastic lip 41 elastically abuts against the outer wall of the needle rod 30.

[0051] Among them, the upper oil seal 40 can adopt any oil seal structure of known structure. The following is only an exemplary description to introduce in detail the optimal upper oil seal structure: two upper elastic lips 41 are fixedly connected to the inner side of the top end of the upper oil seal 40, and the two upper elastic lips 41 are located directly above the lower bushing 20, the upper elastic lip 41 extends obliquely upward and elastically abuts against the needle rod 30, and the upper elastic lip 41 located at the bottom extends obliquely downward and elastically abuts against the needle rod 30, and the two upper elastic lips 41 and the needle rod 30 form an upper annular sealing cavity 42, and the upper annular sealing cavity 42 is filled with lubricating grease.

[0052] Preferably, Figure 4 As shown, the upper oil seal 40 includes an upper axial portion 43 and an upper radial portion 44. The bottom end of the upper axial portion 43 is sleeved on the outside of the lower bushing 20, and the bottom end of the upper axial portion 43 is fixedly connected to the top end of the lower bushing 20 by a snap connection (it can also be an interference fit or a glue connection); the outer peripheral side of the upper radial portion 44 is fixedly connected to the top end of the upper axial portion 43, and the inner peripheral side of the upper radial portion 44 is fixedly connected to the two upper elastic lips 41.

[0053] Specifically, the detachable fixed connection between the upper oil seal 40 and the lower bushing 20 is achieved as follows: an upper connecting groove 22 is formed on the outer circumferential surface of the top end of the lower bushing 20, and the upper connecting groove 22 surrounds the lower bushing 20, and an upper connecting protrusion 45 is formed on the inner circumferential surface of the top end of the upper oil seal 40, and the upper connecting protrusion 45 surrounds the upper oil seal 40, and the upper connecting protrusion 45 is snapped into the upper connecting groove 22.

[0054] An upper limit groove 47 is formed on the inner circumferential surface of the upper axial portion 43, and the upper limit groove 47 surrounds the upper oil seal 40. The upper limit groove 47 is located between the upper connecting protrusion 45 and the upper radial portion 44. An upper limit convex ring is formed between the upper connecting groove 22 and the top end surface of the lower bushing 20. The upper limit convex ring is accommodated in the upper limit groove 47 and axially fixes the upper oil seal 40 and the lower bushing 20.

[0055] More preferably, an L-shaped rigid frame 60 is pre-buried inside the upper oil seal 40 .

[0056] The lower oil seal 50 is sleeved on the lower bushing 20, and the top end of the lower oil seal 50 is detachably fixedly connected to the bottom end of the lower bushing 20, and two lower elastic lips 51 are fixedly connected to the inner side of the bottom end of the lower oil seal 50, and the two lower elastic lips 51 are located directly below the lower bushing 20, the upper lower elastic lip 51 extends obliquely upward and elastically abuts against the needle rod 30, and the lower elastic lip 51 located below extends obliquely downward and elastically abuts against the needle rod 30, and the two lower elastic lips 51 and the needle rod 30 form a lower annular sealing chamber 52, and the lower annular sealing chamber 52 is filled with lubricating grease.

[0057] Preferably, Figure 5 As shown, the lower oil seal 50 includes a lower axial portion 53 and a lower radial portion 54, the top end of the lower axial portion 53 is sleeved on the outer side of the bottom end of the lower bushing 20, and the top end of the lower axial portion 53 is fixedly connected to the bottom end of the lower bushing 20 by a snap connection, the outer peripheral side of the lower radial portion 54 is fixedly connected to the bottom end of the lower axial portion 53, and the inner peripheral side of the lower radial portion 54 is fixedly connected to the two lower elastic lips 51.

[0058] Specifically, the detachable fixed connection between the lower oil seal 50 and the lower bushing 20 is achieved as follows: a lower connecting groove 23 is formed on the outer circumferential surface of the bottom end of the lower bushing 20, and the lower connecting groove 23 surrounds the lower bushing 20; a lower connecting protrusion 55 is formed on the inner circumferential surface of the top end of the lower oil seal 50, and the lower connecting protrusion 55 surrounds the lower oil seal 50, and the lower connecting protrusion 55 is snap-fitted into the lower connecting groove 23.

[0059] A lower limit groove 57 is formed on the inner circumferential surface of the lower axial portion 53, and the lower limit groove 57 surrounds the lower oil seal 50. The lower limit groove 57 is located between the lower connecting protrusion 55 and the lower radial portion 54. A lower limit convex ring is formed between the lower connecting groove 23 and the bottom end surface of the lower bushing 20. The lower limit convex ring is accommodated in the lower limit groove 57, and the lower oil seal 50 and the lower bushing 20 are axially fixedly connected.

[0060] More preferably, an L-shaped rigid frame 60 is pre-buried inside the lower oil seal 50 .

[0061] In other embodiments, Figure 1 , Figure 2 , Figure 4 and Figure 5 As shown, an upper tightening groove 46 is formed on the outer circumferential surface of the upper oil seal 40, and the number of the upper tightening grooves 46 is one or more, and the position of at least one upper tightening groove 46 corresponds to the position of the upper connecting protrusion 45, that is, the upper tightening groove 46 and the upper connecting protrusion 45 are located on the same cross-section of the upper oil seal 40, and an upper tightening spring 70 is tightened in the upper tightening groove 46 to improve the firmness and sealing of the connection between the upper oil seal 40 and the lower bushing 20.

[0062] A lower clamping groove 56 is formed on the outer circumferential surface of the lower oil seal 50. The number of the lower clamping grooves 56 is one or more. The position of at least one lower clamping groove 56 corresponds to the position of the lower connecting protrusion 55, that is, the lower clamping groove 56 and the lower connecting protrusion 55 are located on the same cross-section of the lower oil seal 50. And a lower clamping spring 80 is clamped in the lower clamping groove 56 to improve the firmness and sealing performance of the connection between the lower oil seal 50 and the lower bushing 20.

[0063] In other embodiments, such as Figure 1 、 Figure 2 and Figure 3 shown, the grease storage groove 21 is an annular groove, and the grease storage groove 21 surrounds the lower bushing 20 for one week. An upper connecting groove 22 for connecting with the upper oil seal 40 is formed at the top end of the lower bushing 20, and a lower connecting groove 23 for connecting with the lower oil seal 50 is formed at the bottom end of the lower bushing 20. And in the axial direction of the lower bushing 20, the grease storage groove 21 is located between the upper connecting groove 22 and the lower connecting groove 23, that is, the grease storage groove 21 is formed in the middle of the inner circumferential surface of the lower bushing 20.

[0064] Preferably, an external oil injection hole 11 is formed on the machine housing 10, and an internal oil injection hole 24 is formed on the lower bushing 20. The inner end of the internal oil injection hole 24 is communicated with the grease storage groove 21, and the outer end of the internal oil injection hole 24 is connected with the external oil injection hole 11, that is, the internal oil injection hole 24 is aligned with the external oil injection hole 11 for injecting lubricating grease into the grease storage groove 21. And a plugging screw (not shown in the figure) is detachably and fixedly connected in the external oil injection hole 11.

[0065] Embodiment, a sewing machine, which includes the above-mentioned closed type needle bar anti-oil structure.

[0066] The working process of the closed type needle bar anti-oil structure of the present application is as follows:

[0067] When the sewing machine is working, the needle bar 30 reciprocates up and down. The lubricating grease in the grease storage groove 21 adheres to the needle bar 30, playing a lubricating role between the needle bar 30 and the lower bushing 20. And when the needle bar 30 passes through the upper oil seal 40 and the lower oil seal 50, the lubricating grease is sealed between the lower bushing 20, the upper oil seal 40 and the lower oil seal 50 by the upper elastic lip 41 of the upper oil seal 40 and the lower elastic lip 51 of the lower oil seal 50, forming a closed lubricating structure and continuously playing a lubricating role.

[0068] When the needle bar 30 reciprocates up and down, the lower elastic lip 51 of the lower oil seal 50 is always in contact with the needle bar 30, which can prevent the thread hair from entering the gap between the needle bar 30 and the lower bushing 20, and prevent the lubricating grease from leaking out and the thread hair from getting stuck in the needle bar 30. The inside of the machine head can still be lubricated with lubricating oil. The upper oil seal 40 can prevent the lubricating oil of other structures inside the machine head from entering the gap between the needle bar 30 and the lower bushing 20, and prevent the lubricating oil from seeping through the gap between the needle bar 30 and the lower bushing 20 to contaminate the fabric; at the same time, the upper oil seal 40 can also prevent the iron powder and thread hair inside the machine head from entering the gap between the needle bar 30 and the lower bushing 20 after long-term operation.

[0069] Compared with the prior art, this application has at least the following beneficial technical effects:

[0070] The closed needle bar oil-proof structure in the present application not only lubricates the needle bar, but also prevents the lubricating oil inside the machine head from leaking out. It has anti-thread jamming and dust-proof effects, as well as the advantages of simple structure, easy installation and easy maintenance.

[0071] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and substitutions can be made without departing from the technical principle of the present invention. These improvements and substitutions should also be regarded as the protection scope of the present invention.

Claims

1. A closed needle bar oil-proof structure, characterized in that: include: Housing (10); A lower bushing (20), the lower bushing (20) being mounted on the housing (10), and a grease storage groove (21) being formed on the inner circumferential surface of the lower bushing (20); A needle rod (30), the needle rod (30) is axially movable and penetrates the lower bushing (20), and the radial dimension of the fat storage groove (21) is greater than the radial dimension of the needle rod (30); An upper oil seal (40), wherein the upper oil seal (40) is sleeved on the lower bushing (20), and the bottom end of the upper oil seal (40) is fixedly connected to the top end of the lower bushing (20), and the top end of the upper oil seal (40) is sealedly connected to the needle rod (30); A lower oil seal (50) is sleeved on the lower bushing (20), and the top end of the lower oil seal (50) is fixedly connected to the bottom end of the lower bushing (20), and the bottom end of the lower oil seal (50) is sealingly connected to the needle rod (30).

2. A closed needle bar oil-proof structure according to claim 1, characterized in that: The bottom end of the lower oil seal (50) is connected to two lower elastic lips (51), and the lower elastic lips (51) are located directly below the lower bushing (20). The upper lower elastic lip (51) extends obliquely upward and elastically abuts against the needle rod (30), and the lower elastic lip (51) extends obliquely downward and elastically abuts against the needle rod (30). The two lower elastic lips (51) and the needle rod (30) form a lower annular sealing cavity (52), and the lower annular sealing cavity (52) is filled with lubricating grease.

3. A closed needle bar oil-proof structure according to claim 2, characterized in that: The lower oil seal (50) comprises a lower axial portion (53) and a lower radial portion (54); the top end of the lower axial portion (53) is detachably fixedly connected to the bottom end of the lower bushing (20); the outer peripheral side of the lower radial portion (54) is fixedly connected to the bottom end of the lower axial portion (53); and the inner peripheral side of the lower radial portion (54) is fixedly connected to two lower elastic lips (51).

4. The closed needle bar oil-proof structure according to claim 1, characterized in that: The top end of the upper oil seal (40) is connected to two upper elastic lips (41), and the upper elastic lips (41) are located directly above the lower bushing (20). The upper elastic lip (41) located at the top extends obliquely upward and elastically abuts against the needle rod (30), and the upper elastic lip (41) located at the bottom extends obliquely downward and elastically abuts against the needle rod (30), and the two upper elastic lips (41) and the needle rod (30) form an upper annular sealing cavity (42), and the upper annular sealing cavity (42) is filled with lubricating grease.

5. A closed needle bar oil-proof structure according to claim 4, characterized in that: The upper oil seal (40) comprises an upper axial portion (43) and an upper radial portion (44); the bottom end of the upper axial portion (43) is detachably fixedly connected to the top end of the lower bushing (20); the outer peripheral side of the upper radial portion (44) is fixedly connected to the bottom end of the upper axial portion (43); and the inner peripheral side of the upper radial portion (44) is fixedly connected to two upper elastic lips (41).

6. The closed needle bar oil-proof structure according to claim 1, characterized in that: An upper connecting groove (22) is provided on the outer circumferential surface of the top end of the lower bushing (20), and an upper connecting protrusion (45) is formed on the inner circumferential surface of the bottom end of the upper oil seal (40), and the upper connecting protrusion (45) is snap-fitted into the upper connecting groove (22); a lower connecting groove (23) is provided on the outer circumferential surface of the bottom end of the lower bushing (20), and a lower connecting protrusion (55) is formed on the inner circumferential surface of the top end of the lower oil seal (50), and the lower connecting protrusion (55) is snap-fitted into the lower connecting groove (23).

7. A closed needle bar oil-proof structure according to claim 6, characterized in that: An upper tightening groove (46) is formed on the outer circumferential surface of the upper oil seal (40), the upper connecting protrusion (45) corresponds to the upper tightening groove (46), and an upper tightening spring (70) for tightening the upper oil seal (40) is accommodated in the upper tightening groove (46); a lower tightening groove (56) is formed on the outer circumferential surface of the lower oil seal (50), the lower connecting protrusion (55) corresponds to the lower tightening groove (56), and a lower tightening spring (80) for tightening the lower oil seal (50) is accommodated in the lower tightening groove (56).

8. The closed needle bar oil-proof structure according to claim 1, characterized in that: The fat storage groove (21) is an annular groove.

9. A closed needle bar oil-proof structure according to claim 8, characterized in that: An external oil injection hole (11) is formed on the casing (10), an internal oil injection hole (24) communicating with the grease storage groove (21) is formed on the lower bushing (20), and the external oil injection hole (11) is communicated with the internal oil injection hole (24).

10. A sewing machine, characterized in that: The sewing machine comprises the closed needle bar oil-proof structure according to any one of claims 1 to 9.

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