Needle bar oil-proof device and sewing machine

Abstract

The utility model discloses a needle bar oil-proof device and a sewing machine in the technical field of sewing machines. The needle bar oil-proof device comprises a needle bar, the lower bush is arranged on the needle rod in a sleeving manner, and the lower bush and the needle rod can move relative to each other in the axial direction; the oil sealing sleeve is arranged on the lower lining in a sleeving mode, the top end of the oil sealing sleeve is fixedly connected with the bottom end of the lower lining, the bottom end of the oil sealing sleeve is connected with an upper elastic lip and a lower elastic lip, the upper elastic lip and the lower elastic lip are located under the lower lining, the upper elastic lip extends upwards in an inclined mode and elastically abuts against the needle rod, and the lower elastic lip extends downwards in an inclined mode. And the lower elastic lip obliquely extends downwards and is elastically propped against the needle rod. The oil-proof device not only can prevent lubricating oil from seeping down from the gap between the needle rod and the lower lining and prevent sewing materials from being polluted, but also can prevent the needle rod from clamping thread hairs, and is 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 needle bar oil-proof device 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] Patent No. CN210765820U discloses a sewing machine needle bar oil-proof device, which is provided with an oil-absorbing material at the bottom end of the lower bushing, and the oil-absorbing material is connected to the oil-absorbing power source through an oil-absorbing pipe. When the needle bar and the lower bushing are operating normally, the oil-absorbing material can absorb excess lubricating oil, thereby preventing the lubricating oil from flowing out and contaminating the sewing material. However, the structure of this oil-proof device is complex and the cost is high.

[0004] Moreover, in actual production activities, after a period of use, some thread hair will be absorbed by the needle bar of the sewing machine. These thread hairs can easily enter the lower bushing during the high-speed reciprocating motion of the needle bar, causing the problem of thread hair getting stuck in the needle bar.

[0005] Therefore, how to prevent the lubricating oil from flowing out and prevent the needle bar from getting stuck 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 needle bar oil prevention device to solve the technical problems of the existing oil prevention device having a complex structure and high cost.

[0007] The technical solution adopted by the utility model is: a needle bar oil prevention device, comprising:

[0008] Needle bar;

[0009] A lower bushing, wherein the lower bushing is sleeved on the needle rod, and the lower bushing and the needle rod can move axially relative to each other;

[0010] An oil seal sleeve is arranged on the lower bushing, and the top end of the oil seal sleeve is fixedly connected to the bottom end of the lower bushing, the bottom end of the oil seal sleeve is connected with an upper elastic lip and a lower elastic lip, the upper elastic lip and the lower elastic lip are located directly below the lower bushing, the upper elastic lip extends obliquely upward and elastically abuts against the needle rod, and the lower elastic lip extends obliquely downward and elastically abuts against the needle rod.

[0011] Preferably, the upper elastic lip, the lower elastic lip and the needle rod form an annular sealing cavity, and the annular sealing cavity is filled with grease.

[0012] Preferably, the oil seal sleeve includes an axial portion and a radial portion, the axial portion is detachably fixedly connected to the lower bushing, the outer peripheral side of the radial portion is fixedly connected to the bottom end of the axial portion, the inner peripheral side of the radial portion is fixedly connected to the upper elastic lip and the lower elastic lip, and the radial portion, the axial portion and the upper elastic lip form an oil storage tank.

[0013] Preferably, a rigid frame is provided inside the oil seal sleeve, and the rigid frame includes a horizontal section and a vertical section which are vertically fixedly connected, the vertical section is coated inside the axial section, and the horizontal section is coated inside the radial section.

[0014] Preferably, an annular protrusion for tightly connecting the oil seal sleeve and the lower bushing is formed on the inner circumferential surface of the axial portion.

[0015] Preferably, a connecting groove is provided on the outer circumferential surface of the lower bushing, a connecting protrusion is formed on the inner circumferential surface of the axial portion, and the connecting protrusion is accommodated in the connecting groove.

[0016] Preferably, a first positioning groove corresponding to the connecting protrusion is formed on the outer circumferential surface of the axial portion, and an annular spring for tightening the oil seal sleeve is accommodated in the first positioning groove.

[0017] Preferably, the inner diameter of the connecting protrusion is smaller than the inner diameter of the connecting groove, so that the connecting protrusion elastically abuts against the axial portion.

[0018] Preferably, an installation slope is provided at one end of the connecting protrusion away from the radial portion.

[0019] Preferably, a limiting groove is formed on the inner circumferential surface of the axial portion, and the limiting groove is located between the connecting protrusion and the radial portion. A limiting protrusion is formed on the outer circumferential surface of the lower bushing, and the limiting protrusion is accommodated in the limiting groove and axially fixes the oil seal sleeve and the lower bushing.

[0020] Preferably, a second positioning groove corresponding to the limiting groove is formed on the outer circumferential surface of the axial portion, and an annular spring for tightening the oil seal sleeve is arranged in the second positioning groove.

[0021] Preferably, the oil seal sleeve is made of fluororubber.

[0022] Preferably, the difference between the inner diameter of the upper elastic lip and the outer diameter of the needle rod is 0.4 mm to 0.9 mm; the difference between the inner diameter of the lower elastic lip and the outer diameter of the needle rod is 0 mm to 0.25 mm.

[0023] The second purpose of the utility model is to provide a sewing machine, comprising the needle bar oil-proof device and a housing, wherein the lower bushing is fixedly installed in the mounting hole of the housing along the vertical direction.

[0024] Beneficial effects of the utility model:

[0025] The utility model provides an oil seal sleeve on the outer side of the needle bar, the top end of the oil seal sleeve is fixedly connected to the bottom end of the lower bushing, and the bottom end of the oil seal sleeve is connected with an upper elastic lip extending obliquely upward and a lower elastic lip extending obliquely downward, the inner diameter of the upper elastic lip is smaller than the outer diameter of the needle bar, and the inner diameter of the lower elastic lip is smaller than or equal to the outer diameter of the needle bar, so that after the oil seal sleeve is sleeved on the needle bar, the upper elastic lip and the lower elastic lip radially squeeze the needle bar and elastically deform, thereby realizing a sealed connection between the bottom end of the oil seal sleeve and the needle bar; at the same time, since the upper elastic lip extends obliquely upward, when the needle bar moves axially downward, the sealing effect of the upper elastic lip and the needle bar will be better, thereby preventing the lubricating oil from flowing out; since the lower elastic lip extends obliquely downward, when the needle bar moves axially upward, the sealing effect of the lower elastic lip and the needle bar will be better, thereby preventing the thread hair from entering the gap between the needle bar and the lower bushing, effectively preventing the lubricating oil from seeping out and the occurrence of the phenomenon of the needle bar thread hair being stuck. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 This is one of the structural schematic diagrams of the needle bar oil prevention device of the utility model;

[0027] Figure 2 This is one of the structural schematic diagrams of the oil seal sleeve;

[0028] Figure 3 This is the second structural schematic diagram of the needle bar oil prevention device of the utility model;

[0029] Figure 4 This is the second structural diagram of the oil seal sleeve;

[0030] Figure 5 is a structural schematic diagram of the lower bushing;

[0031] Figure 6 It is a structural schematic diagram of a sewing machine of the utility model.

[0032] Description of reference numerals in the figures:

[0033] 10. Needle bar;

[0034] 20. lower bushing; 21. connecting groove; 22. limiting protrusion;

[0035] 30. Oil seal sleeve; 31. Upper elastic lip; 32. Lower elastic lip; 33. Axial portion; 34. Radial portion; 35. Oil storage tank; 331. Annular protrusion; 332. Connecting protrusion; 333. First positioning groove; 334. Mounting inclined surface; 335. Limiting groove; 336. Second positioning groove; 337. Limiting surface; 40. Grease;

[0036] 50. Rigid skeleton;

[0037] 60. Ring spring;

[0038] 70. Shell. DETAILED DESCRIPTION

[0039] The following is a further detailed description of the specific implementations of the present invention in conjunction with the accompanying drawings. These implementations are only used to illustrate the present invention, but not to limit the present invention.

[0040] In the description of the present invention, it should be noted that the terms "center", "longitudinal", "lateral", "upper", "lower", "front", "back", "left", "right", "vertical", "horizontal", "top", "bottom", "inside", "outside" and the like indicate positions or positional relationships based on the positions or positional relationships shown in the accompanying drawings, and are only for the convenience of describing the present invention and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, be constructed and operate in a specific orientation, and therefore cannot be understood as a limitation on the present invention. In addition, the terms "first" and "second" are used for descriptive purposes only and cannot be understood as indicating or implying relative importance.

[0041] In the description of the present invention, it should be noted that, unless otherwise clearly specified and limited, the terms "installation", "connection" and "connection" should be understood in a broad sense, for example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, or it can be indirectly connected through an intermediate medium, or it can be the internal communication of two components. For ordinary technicians in this field, the specific meanings of the above terms in the present invention can be understood according to specific circumstances.

[0042] In addition, in the description of the present invention, unless otherwise specified, “plurality” means two or more.

[0043] Examples, such as Figure 1-Figure 6As shown, a needle bar oil-proof device comprises: a needle bar 10, a lower bushing 20 and an oil seal sleeve 30, wherein the lower bushing 20 is sleeved on the needle bar 10, and the lower bushing 20 and the needle bar 10 can move axially relative to each other; the oil seal sleeve 30 is sleeved on the lower bushing 20, and the top end of the oil seal sleeve 30 is fixedly connected to the bottom end of the lower bushing 20, and the bottom end of the oil seal sleeve 30 is connected with an upper elastic lip 31 and a lower elastic lip 32, and the upper elastic lip 31 and the lower elastic lip 32 are located directly below the lower bushing 20, and the upper elastic lip 31 extends obliquely upward and elastically abuts against the needle bar 10, and the lower elastic lip 32 extends obliquely downward and elastically abuts against the needle bar 10.

[0044] The present application has an oil seal sleeve 30 sleeved on the outer side of the needle rod 10, the top end of the oil seal sleeve 30 is fixedly connected to the bottom end of the lower bushing 20, and the bottom end of the oil seal sleeve 30 is connected to an upper elastic lip 31 extending obliquely upward and a lower elastic lip 32 extending obliquely downward, the inner diameter of the upper elastic lip 31 is smaller than the outer diameter of the needle rod 10, and the inner diameter of the lower elastic lip 32 is smaller than or equal to the outer diameter of the needle rod 10, so that after the oil seal sleeve 30 is sleeved on the needle rod 10, the upper elastic lip 31 and the lower elastic lip 32 radially squeeze the needle rod 10 and cause elastic deformation, A sealed connection between the bottom end of the oil seal sleeve 30 and the needle rod 10 is achieved; at the same time, since the upper elastic lip 31 extends obliquely upward, when the needle rod 10 moves axially downward, the sealing effect between the upper elastic lip 31 and the needle rod 10 will be better, thereby preventing the lubricating oil from flowing out; since the lower elastic lip 32 extends obliquely downward, when the needle rod 10 moves axially upward, the sealing effect between the lower elastic lip 32 and the needle rod 10 will be better, thereby preventing the thread hair from entering the gap between the needle rod 10 and the lower bushing 20, and effectively preventing the lubricating oil from leaking out and the thread hair from getting stuck in the needle rod 10.

[0045] It should be noted that: in the present application, the elastic contact between the upper elastic lip 31 and the needle rod 10 means that the upper elastic lip 31 and the needle rod 10 are in contact, and the end of the upper elastic lip 31 that contacts the needle rod 10 is elastically deformed.

[0046] In a specific embodiment, if Figure 1-Figure 4 As shown, the upper elastic lip 31 and the lower elastic lip 32 are both arranged around the axis of the needle rod 10, and an annular sealing cavity (not shown in the figure) is formed between the upper elastic lip 31, the lower elastic lip 32 and the needle rod 10, and the annular sealing cavity is filled with grease 40 for lubricating the relative movement between the upper elastic lip 31, the lower elastic lip 32 and the needle rod 10, and also for filling and sealing the gap between the upper elastic lip 31 and the lower elastic lip 32.

[0047] In a specific embodiment, if Figure 1 and Figure 3 As shown, the top end of the oil seal sleeve 30 is detachably fixedly connected to the bottom end of the lower bushing 20 .

[0048] Specifically, Figure 2 and Figure 4 As shown, the oil seal sleeve 30 includes an axial portion 33 and a radial portion 34, the axial portion 33 is arranged along the axial direction of the needle rod 10, and the top end of the axial portion 33 is detachably fixedly connected to the lower bushing 20; the radial portion 34 is arranged along the radial direction of the needle rod 10, and the outer peripheral side of the radial portion 34 is fixedly connected to the bottom end of the axial portion 33, the inner peripheral side of the radial portion 34 is fixedly connected to the upper elastic lip 31 and the lower elastic lip 32, and the radial portion 34, the axial portion 33 and the upper elastic lip 31 form an oil storage groove 35, which is used to store the lubricating oil flowing out from between the needle rod 10 and the lower bushing 20.

[0049] More preferably, a rigid skeleton 50 is provided inside the oil seal sleeve 30, and the rigid skeleton 50 surrounds the axis of the needle rod 10, and the rigid skeleton 50 includes a horizontal section and a vertical section that are vertically fixedly connected, the vertical section is covered inside the axial section 33, and the horizontal section is covered inside the radial section 34, and the rigid skeleton 50 is used to improve the rigidity of the oil seal sleeve 30.

[0050] In a specific embodiment, if Figure 3 and Figure 4 As shown, the detachable fixed connection between the top end of the oil seal sleeve 30 and the bottom end of the lower bushing 20 is a hugging connection.

[0051] Specifically, Figure 3 and Figure 4 As shown, an annular protrusion 331 is formed on the inner circumferential surface of the axial portion 33 of the oil seal sleeve 30, and the annular protrusion 331 surrounds the axis of the needle rod 10. There are multiple annular protrusions 331, and the multiple annular protrusions 331 are linearly distributed along the axial direction; the inner diameter of the annular protrusion 331 is smaller than the outer diameter of the lower bushing 20, so that the oil seal sleeve 30 is tightly connected to the lower bushing 20.

[0052] In a specific embodiment, if Figure 1 and Figure 2 As shown, the detachable fixed connection between the top end of the oil seal sleeve 30 and the bottom end of the lower bushing 20 is a snap-on connection.

[0053] Specifically, Figure 1 , Figure 2 and Figure 6 As shown, a connecting groove 21 is provided on the outer circumferential surface of the bottom end of the lower bushing 20, and the connecting groove 21 surrounds the axis of the needle rod 10; a connecting protrusion 332 is formed on the inner circumferential surface of the axial portion 33, and the connecting protrusion 332 surrounds the axis of the needle rod 10, and the inner diameter of the connecting protrusion 332 is smaller than the outer diameter of the lower bushing 20 and is accommodated in the connecting groove 21, so that the oil seal sleeve 30 is axially fixedly connected to the lower bushing 20.

[0054] Preferably, the inner diameter of the connecting protrusion 332 is smaller than the inner diameter of the connecting groove 21 , so that the connecting protrusion 332 elastically abuts against the bottom wall of the connecting groove 21 to prevent the lubricating oil from flowing out of the gap between the oil seal sleeve 30 and the lower bushing 20 .

[0055] More preferably, Figure 1 and 2 As shown, the end of the connecting protrusion 332 away from the radial portion 34 is provided with a mounting bevel 334, and the end of the connecting protrusion 332 close to the radial portion 34 is a plane, that is, the top of the connecting protrusion 332 is formed with a mounting bevel 334, and the bottom of the connecting protrusion 332 is formed with a plane; from top to bottom, the radial spacing between the mounting bevel 334 and the needle rod 10 gradually decreases, so that the connecting protrusion 332 can be accommodated in the connecting groove 21, that is, it is convenient to fix the oil seal sleeve 30 on the outer side of the bottom end of the lower bushing 20.

[0056] In a specific embodiment, if Figure 1 and Figure 2 As shown, a first positioning groove 333 corresponding to the connecting protrusion 332 on the inner circumferential surface of the axial portion 33 is formed on the outer circumferential surface of the axial portion 33, and an annular spring 60 for tightening the oil seal sleeve 30 is arranged in the first positioning groove 333, so that a radial force is applied to the oil seal sleeve 30 through elastic deformation of the annular spring 60 to prevent the connecting protrusion 332 from escaping from the first positioning groove 333, thereby ensuring the connection and sealing effect between the oil seal sleeve 30 and the lower bushing 20.

[0057] In a specific embodiment, if Figure 1 and Figure 2 As shown, a limiting groove 335 is formed on the inner circumferential surface of the axial portion 33, and the limiting groove 335 surrounds the axis of the needle rod 10, and the limiting groove 335 is located between the connecting protrusion 332 and the radial portion 34; a limiting protrusion 22 is formed on the outer circumferential surface of the lower bushing 20, and the limiting protrusion 22 surrounds the axis of the needle rod 10, and the limiting protrusion 22 is accommodated in the limiting groove 335, and the oil seal sleeve 30 and the lower bushing 20 are axially fixedly connected.

[0058] Preferably, a second positioning groove 336 corresponding to the limiting groove 335 is formed on the outer circumferential surface of the axial portion 33, and an annular spring 60 for tightening the oil seal sleeve 30 is arranged in the second positioning groove 336, so that a radial force is applied to the oil seal sleeve 30 through elastic deformation of the annular spring 60 to prevent the limiting protrusion 22 from escaping from the limiting groove 335, thereby ensuring the axial connection effect between the oil seal sleeve 30 and the lower bushing 20.

[0059] In a specific embodiment, if Figure 1 and Figure 3As shown, a limiting surface 337 that fits with the lower end surface of the lower bushing 20 is provided on the axial portion 33 or the radial portion 34 of the oil seal sleeve 30 to prevent the oil seal sleeve 30 and the lower bushing 20 from relative axial movement. Preferably, the lower end surface of the limiting protrusion 22 is coplanar with the lower end surface of the lower bushing 20, the lower groove wall surface of the limiting groove 335 is the limiting surface 337, the limiting protrusion 22 is accommodated in the limiting groove 335, and the lower end surface of the limiting protrusion 22 fits with the limiting surface 337 of the limiting groove 335 to prevent the lower bushing 20 and the oil seal sleeve 30 from relative axial movement.

[0060] In a specific embodiment, if Figure 1-Figure 4 As shown, the oil seal sleeve 30 is made of fluororubber, so that the oil seal sleeve 30 can be sleeved on the outside of the lower bushing 20, and the upper elastic lip 31 and the lower elastic lip 32 can be elastically deformed under the action of external force and have strong wear resistance.

[0061] Preferably, the upper elastic lip 31 , the lower elastic lip 32 , the axial portion 33 and the radial portion 34 of the oil seal sleeve 30 are integrally formed and wrapped around the outside of the rigid frame 50 .

[0062] In a specific embodiment, if Figure 1-Figure 4 As shown, the inner diameter of the upper elastic lip 31 and the lower elastic lip 32 is smaller than or equal to the outer diameter of the needle rod 10 .

[0063] Preferably, the difference between the inner diameter of the upper elastic lip 31 and the outer diameter of the needle rod 10 is 0.4 mm to 0.9 mm; the difference between the inner diameter of the lower elastic lip 32 and the outer diameter of the needle rod 10 is 0 mm to 0.25 mm.

[0064] A sewing machine, such as Figure 6 As shown, the sewing machine includes the needle bar oil-proof device and a housing 70, and the lower bushing 20 is fixedly installed in the mounting hole of the housing 70 along the vertical direction.

[0065] The working principle of the oil protection device in this application is as follows:

[0066] When the sewing machine is working, the needle bar 10 reciprocates up and down, and the needle bar 10 passes through the lower bushing 20 and the oil seal 30. When the lubricating oil in the sewing machine head seeps downward through the gap between the needle bar 10 and the lower bushing 20, when it encounters the upper elastic lip 31, the lubricating oil is blocked and cannot continue to pass, and is stored in the oil storage tank 35 inside the oil seal 30. When the needle bar 10 moves upward, the thread hair attached to the needle bar 10 encounters the lower elastic lip 32 and is blocked, thereby preventing the thread hair from getting stuck in the gap between the needle bar 10 and the lower bushing 20.

[0067] Compared with the prior art, this application has at least the following beneficial technical effects:

[0068] 1. It can not only prevent lubricating oil from seeping into the gap between the needle bar and the lower bushing to prevent the contamination of sewing materials, but also prevent the needle bar from getting stuck.

[0069] 2. Simple structure, easy installation, easy maintenance and low production cost.

[0070] 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 needle bar oil-proof device, characterized in that: include: Needle bar (10); A lower bushing (20), wherein the lower bushing (20) is sleeved on the needle rod (10), and the lower bushing (20) and the needle rod (10) are capable of relative axial movement; An oil seal sleeve (30), wherein the oil seal sleeve (30) is sleeved on the lower bushing (20), and the top end of the oil seal sleeve (30) is fixedly connected to the bottom end of the lower bushing (20), and the bottom end of the oil seal sleeve (30) is connected to an upper elastic lip (31) and a lower elastic lip (32), wherein the upper elastic lip (31) and the lower elastic lip (32) are located directly below the lower bushing (20), wherein the upper elastic lip (31) extends obliquely upward and elastically abuts against the needle rod (10), and wherein the lower elastic lip (32) extends obliquely downward and elastically abuts against the needle rod (10).

2. The needle bar oil-proof device according to claim 1, characterized in that: The upper elastic lip (31), the lower elastic lip (32) and the needle rod (10) form an annular sealing cavity, and the annular sealing cavity is filled with lubricating grease (40).

3. The needle bar oil-proof device according to claim 1, characterized in that: The oil seal sleeve (30) comprises an axial portion (33) and a radial portion (34); the axial portion (33) is detachably fixedly connected to the lower bushing (20); the outer peripheral side of the radial portion (34) is fixedly connected to the bottom end of the axial portion (33); the inner peripheral side of the radial portion (34) is fixedly connected to the upper elastic lip (31) and the lower elastic lip (32); and the radial portion (34), the axial portion (33) and the upper elastic lip (31) form an oil storage tank (35).

4. The needle bar oil-proof device according to claim 3, characterized in that: A rigid frame (50) is provided inside the oil seal sleeve (30), and the rigid frame (50) comprises a horizontal section and a vertical section which are vertically fixedly connected, the vertical section is enclosed inside the axial section (33), and the horizontal section is enclosed inside the radial section (34).

5. The needle bar oil-proof device according to claim 3, characterized in that: An annular protrusion (331) is formed on the inner circumferential surface of the axial portion (33) for tightly connecting the oil seal sleeve (30) and the lower bushing (20).

6. The needle bar oil-proof device according to claim 3, characterized in that: A connecting groove (21) is provided on the outer circumferential surface of the lower bushing (20), a connecting protrusion (332) is formed on the inner circumferential surface of the axial portion (33), and the connecting protrusion (332) is accommodated in the connecting groove (21).

7. The needle bar oil-proof device according to claim 6, characterized in that: A first positioning groove (333) corresponding to the connecting protrusion (332) is formed on the outer circumferential surface of the axial portion (33), and an annular spring (60) for tightening the oil seal sleeve (30) is accommodated in the first positioning groove (333).

8. The needle bar oil-proof device according to claim 6, characterized in that: The inner diameter of the connecting protrusion (332) is smaller than the inner diameter of the connecting groove (21), so that the connecting protrusion (332) elastically abuts against the axial portion (33).

9. The needle bar oil-proof device according to claim 6, characterized in that: An end of the connecting protrusion (332) away from the radial portion (34) is provided with a mounting inclined surface (334).

10. The needle bar oil protection device according to claim 6, characterized in that: A limiting groove (335) is formed on the inner circumferential surface of the axial portion (33), and the limiting groove (335) is located between the connecting protrusion (332) and the radial portion (34). A limiting protrusion (22) is formed on the outer circumferential surface of the lower bushing (20), and the limiting protrusion (22) is accommodated in the limiting groove (335) so that the oil seal sleeve (30) and the lower bushing (20) are axially fixedly connected.

11. The needle bar oil-proof device according to claim 10, characterized in that: A second positioning groove (336) corresponding to the limiting groove (335) is formed on the outer circumferential surface of the axial portion (33), and an annular spring (60) for tightening the oil seal sleeve (30) is accommodated in the second positioning groove (336).

12. The needle bar oil protection device according to claim 1, characterized in that: The material of the oil seal sleeve (30) is fluorine rubber.

13. The needle bar oil-proof device according to claim 1, characterized in that: The difference between the inner diameter of the upper elastic lip (31) and the outer diameter of the needle rod (10) is 0.4 mm to 0.9 mm; the difference between the inner diameter of the lower elastic lip (32) and the outer diameter of the needle rod (10) is 0 mm to 0.25 mm.

14. A sewing machine, comprising a needle bar oil-proof device according to any one of claims 1 to 13, characterized in that: It also includes a housing (70), wherein the lower bushing (20) is fixedly installed in a mounting hole of the housing (70) along a vertical direction.

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