Nylon worm gasket jacking chain saw structure

Abstract

The invention discloses a nylon worm gasket jacking chain saw structure, and relates to the technical field of chain saws, the nylon worm gasket jacking chain saw structure comprises a worm assembled on an output shaft of a chain saw, the worm outputs power to an oil pump working end of the chain saw through a worm gear, the worm is made of a plastic material, and the worm gear is made of a metal material; the worm is sleeved on the output shaft through a middle assembly hole, and a shaft shoulder is tightly propped against the output shaft; a metal pad is designed at the end of the worm, the metal pad and the worm are integrally formed through injection molding, a through hole corresponding to an assembly hole in the worm in size is formed in the metal pad, the through hole and the assembly hole are coaxially assembled, and the worm abuts against an output shaft through the metal pad. According to the structure, the worm and the output shaft of the chain saw are assembled in an abutting mode through the metal pad, and therefore when the worm and the output shaft rotate relatively, the service life of the worm made of plastic is longer due to the fact that the metal pad abutting against the output shaft is more abrasion-resistant.

Description

Technical Field

[0001] This invention relates to the field of chainsaw technology, specifically to a nylon worm gear gasket clamping structure for chainsaws. Background Technology

[0002] In the transmission structure of a chainsaw, to ensure the normal operation of the oil pump while the chainsaw outputs rotational power, a worm gear structure is typically used to transmit power to the oil pump's operating position on the chainsaw. The worm gear is usually made of nylon, while the worm wheel is made of metal. This material selection utilizes nylon's self-lubricating and shock-absorbing properties, ensuring smooth operation and low noise even under conditions of insufficient oil or impact. Furthermore, this combination of dissimilar materials avoids metal-to-metal seizing. Simultaneously, nylon, as a "sacrificial point" for overload protection, breaks first in the event of chain jamming, protecting the expensive engine and gearbox, thus achieving a balance between cost, safety, and performance.

[0003] To prevent damage to the transmission components when the chainsaw jams, the nylon worm gear is typically fitted directly onto the output shaft during assembly. A clamping mechanism then secures the nylon worm gear to the output shaft. However, if the working end jams, a strong pressure will cause relative friction between the output shaft and the nylon worm gear. This can lead to wear and grooves at the clamping end of the nylon worm gear and the output shaft, ultimately damaging the components.

[0004] In traditional chainsaws, such as the results in the chainsaw clutch and chain cooling device patent with authorization announcement number CN110587721B, the worm gear is usually directly pressed against the crankshaft through the clutch retainer, while the chainsaw sprocket is usually directly mounted on the outside of the retainer. This makes the chain used for cutting further out, resulting in poor stability during operation. In contrast, in the debugging load tooling of a two-stroke gasoline saw patent with authorization announcement number CN220929532U, the clutch is mounted on the outside, and the sprocket is mounted between the clutch and the worm gear. In this case, the worm gear is pressed against the crankshaft through the sprocket. Although this makes the sprocket and the chain it is mounted on closer to the center, resulting in better stability during operation, it also makes it easier for sawdust to enter the transmission position of the worm gear when the chain is cutting wood, which can easily cause jamming. In traditional chainsaw designs, although a larger diameter protective ring is designed on the side of the worm near the sprocket, and the protective ring and the outer retaining shell of the worm gear are used to protect against sawdust, this protective structure is not very effective at blocking sawdust and is still prone to jamming. Furthermore, in this structure, the sprocket is directly pressed against the outer end of the worm, resulting in a narrow assembly area. During chainsaw operation, especially when the chainsaw jams, relative friction can easily occur at the end of the sprocket pressing against the worm, causing wear and grooves in the nylon worm, leading to damage. Additionally, because the mounting bracket, sprocket, and worm mounted on the crankshaft for power output are all rigidly axially pressed, once the nylon worm wears and develops grooves, the entire assembly structure will loosen, accelerating the overall wear of the chainsaw and shortening its lifespan. Summary of the Invention

[0005] To address the aforementioned technical problems, this invention provides a nylon worm gear gasket clamping structure for chainsaws, thereby resolving the technical issues raised in the background section.

[0006] To achieve the above objectives, the technical solution adopted by the present invention is as follows: a nylon worm gear gasket clamping structure for a chainsaw, comprising a worm gear mounted on the output shaft of the chainsaw, wherein the worm gear outputs power to the working end of the chainsaw's oil pump via a worm wheel; the worm gear is made of plastic, and the worm wheel is made of metal; the worm gear is fitted onto the output shaft through a central mounting hole, and its shoulder is clamped to the output shaft; a metal gasket is designed at the end of the worm gear, the metal gasket and the worm gear being injection molded as one piece, and a through hole of a corresponding size to the mounting hole on the worm gear is machined on the metal gasket; the through hole and the mounting hole are coaxially fitted, and the worm gear is clamped to the output shaft by the metal gasket.

[0007] Preferably, the output shaft is designed with a shoulder, and the worm gear is pressed against the shoulder of the output shaft by the metal pad.

[0008] Preferably, the metal pad is annular, with anti-slip texture processed on its outer ring.

[0009] Preferably, the worm gear is made of nylon and the metal pad is made of stainless steel.

[0010] Preferably, the outer ring of the metal pad is uniformly designed with two or more integrally extended buckles, which are bent backward and extended relative to the metal pad.

[0011] Preferably, the rearwardly extending end of the buckle has a protrusion that engages with the worm gear.

[0012] Preferably, the length of the backward extension of the undercut is more than 1 / 2 of the axial length of the worm gear.

[0013] Preferably, the outer ring of the metal pad has an integrally extended retaining clip on the same plane, and the end of the worm gear that assembles with the metal pad has an assembly groove. The metal pad is assembled in the assembly groove, and the retaining clip of the outer ring of the metal pad is engaged with the circumferential wall of the assembly groove. Multiple retaining clips are evenly distributed around the outer ring of the metal pad. The depth of the assembly groove is greater than the thickness of the metal pad, and the end of the worm gear that assembles with the metal pad protrudes inward relative to the metal pad.

[0014] Preferably, the metal pad is integrally stamped with the buckle or undercut.

[0015] Preferably, a clamping ring is integrally machined on the side of the worm gear away from the metal pad, and an assembly cavity with a diameter larger than the diameter of the shaft at the corresponding output shaft assembly position is machined in the middle of the clamping ring. The clamping ring of the worm gear is clamped and assembled with the side of the sprocket, and a clutch housing is assembled on the other side of the sprocket. An assembly bushing extending into the worm gear assembly cavity is machined in the middle of the clutch housing, and the outside of the assembly bushing is connected to the sprocket and the assembly cavity via splines. The assembly cavity is designed with a spline groove corresponding to the spline on the outside of the assembly bushing, and the end of the assembly bushing has a gap from the inner wall of the assembly cavity. The worm is further pressed against the shoulder by the sprocket and the clamping ring.

[0016] Preferably, a protective shell is fitted on the outer side of the worm gear, the protective shell is located inside the pressure ring, the protective shell has a protruding ring on the outer annular surface of the pressure ring, the outer diameter of the pressure ring is larger than the pressure surface of the sprocket, an annular groove is machined on the outer ring position of the side of the pressure ring corresponding to the sprocket, a spacer ring extending inward is fitted on the protruding ring, the inner side of the spacer ring is inserted into the spacer groove, and a tortuous annular connecting cavity is formed between the spacer ring, the protruding ring and the outer side of the pressure ring.

[0017] Compared with the prior art, the beneficial effects of the present invention are: (1) The present invention designs a metal pad structure at the end of the worm gear and uses the metal pad to achieve a tight fit between the worm gear and the output shaft of the chainsaw. When the worm gear and the output shaft rotate relative to each other, the metal pad that is tight to the output shaft is more wear-resistant, which makes the plastic worm gear have a longer service life.

[0018] Furthermore, the outer ring of the metal pad is designed with a protruding retainer. This retainer, embedded in the mounting groove at the end of the worm gear, secures the metal pad to the end of the worm wheel. This completely limits the metal pad's position within the worm wheel, preventing both axial linear movement and axial rotation. This ensures that the metal pad will not detach from the worm gear during relative rotational movement with the output shaft, guaranteeing the stability of the integrated worm gear and metal pad structure.

[0019] Alternatively, the outer ring of the metal pad may be designed with a backward-bending overhang, which embeds itself into the worm gear. This overhang prevents the metal pad from rotating coaxially with the worm gear. Furthermore, the overhang may have a protrusion, which prevents the metal pad from sliding axially out of the worm gear when the overhang is embedded. This ensures the stability of the integrated worm gear and metal pad structure.

[0020] Furthermore, the length of the backward extension of the undercut is more than 1 / 2 of the axial length of the worm gear, so that the undercut is fully inserted into the worm. This ensures the stability of the integrated structure of the worm and metal washer, while the undercut forms a metal rib inside the plastic worm, which can greatly enhance the strength of the entire worm gear and make the worm gear deform less during use.

[0021] (2) In this chainsaw structure, the integrated clamping ring on the worm gear is thicker than the traditional protective ring, making it easier to clamp and assemble with the sprocket. Simultaneously, it is connected to the sprocket and worm gear via the external spline of the mounting bushing on the clutch housing. This ensures synchronous transmission between the sprocket and worm gear, completely preventing relative rotation between the worm gear and sprocket in the event of sprocket jamming. Relative friction only occurs at the metal pad location, effectively reducing wear.

[0022] Furthermore, the clamping ring and the worm are connected by a narrowing edge, so that when the sprocket end face presses against the protective ring, the clamping ring and the worm can generate elastic compression through the narrow edge. In this way, even if there is slight wear at the end of the worm, stable clamping can still be guaranteed.

[0023] Furthermore, a groove structure is machined on the outer side of the clamping ring. By assembling a spacer ring on the convex ring on the outer side of the clamping ring, a tortuous annular connecting cavity is formed between the spacer ring, the convex ring, and the outer side of the clamping ring. This ensures that the protective shell and the worm gear are completely separated and assembled, while making the connection path between the worm gear side and the sprocket side more tortuous, thereby preventing wood chips generated at the sprocket position from entering the worm gear connection position. This ensures the service life of the equipment. Attached Figure Description

[0024] Figure 1 This is a schematic cross-sectional view of the worm gear and worm wheel installation position in Embodiment 1 of the nylon worm gear gasket clamping chainsaw structure of the present invention.

[0025] Figure 2 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 1 of the present invention.

[0026] Figure 3 This is a schematic diagram of the front of the metal pad in Embodiment 1 of the present invention.

[0027] Figure 4 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 2 of the present invention.

[0028] Figure 5 This is a schematic diagram of the three-dimensional structure of the metal pad in Embodiment 2 of the present invention.

[0029] Figure 6 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 3 of the present invention.

[0030] Figure 7 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 3 of the present invention.

[0031] Figure 8 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 4 of the present invention.

[0032] Figure 9 This is a schematic diagram of the front of the metal pad in Embodiment 4 of the present invention.

[0033] Figure 10 This is a cross-sectional structural diagram of the worm gear, sprocket, and clutch housing assembled on the output shaft in Embodiment 5 of the present invention.

[0034] Figure 11 This is a schematic diagram of one side of the worm gear clamping ring in Embodiment 5 of the present invention.

[0035] Figure 12 This is a schematic diagram of the cross-sectional structure of the worm gear in Embodiment 5 of the present invention.

[0036] The numbers on the map are: 1. Output shaft; 11. Shoulder 11; 2. Worm gear; 21. Assembly hole; 22. Pressure ring; 221. Spacing groove; 23. Narrow edge; 24. Assembly groove; 23. Assembly cavity; 231. Spline groove. 3. Worm gear; 4. Metal pad; 41. Through hole; 42. Anti-slip texture; 43. Inverted buckle; 44. Protrusion; 45. Buckle. 5. Sprockets; 6. Protective shell; 61. Raised ring; 62. Spacer ring; 7. Clutch housing; 71. Assembly bushing; 72. Spline. Detailed Implementation

[0037] The technical solutions of the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments. Based on the embodiments of the present invention, all other embodiments obtained by those skilled in the art without creative effort are within the scope of protection of the present invention.

[0038] Example 1 The nylon worm gear gasket clamping structure in this patent is used in chainsaws, such as... Figure 1 and Figure 2 As shown, it includes a worm gear 2 mounted on the output shaft 1 of the chainsaw, which is the output crankshaft of the gasoline chainsaw. In this embodiment, the worm gear 2 outputs power to the working end of the chainsaw's oil pump via a worm wheel 3. The worm gear 2 is made of plastic, and the worm wheel 3 is made of metal; specifically, the worm gear is made of nylon, and the metal washer is made of stainless steel. The main body of the worm gear 2 is ring-shaped, with a transmission helix on its outside. It is fitted onto the output shaft 1 through the central mounting hole 21, and both sides of the worm gear 2 are secured to the output shaft 1. The above structure is the same as the conventional structure.

[0039] In this embodiment, as Figure 2 and Figure 3 As shown, the end of the worm gear 2 is designed with a metal pad 4. During specific processing, the metal pad 4 and the worm gear 2 are injection molded as a single unit. The metal pad 4 has a through hole 41 of a size corresponding to the mounting hole 21 on the worm gear 2. Specifically, the diameter of the through hole 41 in the middle of the metal pad 4 is slightly larger than the diameter of the mounting hole 21 on the worm gear. The through hole 41 and the mounting hole 21 are coaxially assembled, as shown... Figure 1 As shown, the worm gear 2 is pressed against the output shaft 1 by a metal pad 4.

[0040] This invention incorporates an integrally injection-molded metal pad 4 at the end of the worm gear 2. The metal pad 4 enables the worm gear 2 to be tightly fitted to the output shaft 1 of the chainsaw. When the worm gear 2 and the output shaft 1 rotate relative to each other, the metal pad, which is tightly fitted to the output shaft 1, is more wear-resistant, thus extending the service life of the nylon worm gear 2.

[0041] In this embodiment, the output shaft 1 is specifically designed with a shoulder 11, and the worm gear 2 is secured to the shoulder 11 of the output shaft 1 via the metal pad 4. Compared to structures such as snap rings, the design of the shoulder 11 is simpler and makes assembly more convenient. Moreover, the axial assembly dimensions of the shoulder 11 structure are more precise during assembly.

[0042] In the specific design, such as Figure 3 As shown, the metal pad 4 is annular, with anti-slip texture 42 machined on its outer ring. In specific manufacturing, the metal pad 4 is formed by stamping; the annular structure is very convenient to form using stamping, resulting in lower processing costs. Figure 2 As shown, the metal pad 4 is located at the right end of the worm gear 2 during assembly, and the right side plane of the metal pad 4 is flush with the right side plane of the worm gear 2. In this way, the assembly is the same as the traditional worm gear structure, which makes it easier to replace the original structure.

[0043] Example 2 In this embodiment, the assembly method of the worm gear 2 and the output shaft 1 is exactly the same as in Embodiment 1, and will not be repeated here. In the earlier rear embodiment, as... Figure 4 and Figure 5 As shown, the outer ring of the metal pad 4 is uniformly designed with two or more integrally extended undercuts 43, which are bent backwards and extend relative to the metal pad 4. In specific processing, the metal pad 4 and the undercuts 43 can be integrally stamped as a single piece, and then the planar structure of the metal pad 4 and the undercuts 43 can be bent (or bent by continuing stamping) into the shape shown. Figure 5 The structure shown. During injection molding, the metal pad 4 is placed as follows... Figure 4 As shown, the metal pad 4 is placed at the end of the worm gear 2, and then injection molded together with the worm gear 2. In this embodiment, the rearward-extending end of the undercut 43 has a protrusion 44 that engages with the interior of the worm gear 2. Each undercut 43 has two symmetrical protrusions 44 machined at its end.

[0044] The outer ring of the metal pad 4 is designed with a backward-bending buckle 43, which is embedded backward into the worm gear 2. This buckle 43 prevents the metal pad 4 from rotating coaxially relative to the worm gear 2. Furthermore, the buckle has a protrusion 44, which prevents the metal pad 4 from sliding axially out relative to the worm gear 2 when the buckle 43 is embedded in the worm gear 2. This ensures the stability of the integrated structure of the worm gear 2 and the metal pad 4. At the same time, the backward-bending buckle 43 structure does not change the overall diameter, making it more suitable for the integrated worm gear 2 structure with a smaller axial dimension.

[0045] Example 3 In this embodiment, the structure of the worm gear 2 and the metal pad 4 is basically the same as in embodiment 2, except for further details, such as... Figure 6 and Figure 7 As shown, the backward extension of the inverted buckle 43 is more than half the axial length of the worm gear 2. At this point, the inverted buckle 43 is fully inserted into the worm. The integral injection-molded structure of the worm gear 2 and the metal pad 4 ensures the stability of the integrated structure while allowing the inverted buckle 43 to form a metal rib within the plastic worm gear. This significantly strengthens the entire worm gear 2, resulting in less deformation during use. This not only reduces energy loss but also greatly extends the service life of the worm gear.

[0046] Example 4 In this embodiment, such as Figure 8 and Figure 9 As shown, the outer ring of the metal pad 4 has an integrally extended retainer 45 on the same plane. The end of the worm gear that assembles with the metal pad has an assembly groove 24. The metal pad is assembled in the assembly groove 46, and the retainer 45 on the outer ring of the metal pad 4 is engaged in the circumferential wall of the assembly groove 46. In this embodiment, six retainers are evenly distributed circumferentially on the outer ring of the metal pad 4. Specifically, the depth of the assembly groove 46 is greater than the thickness of the metal pad, and the end of the worm gear 2 that assembles with the metal pad 4 protrudes inward relative to the metal pad 4. This ensures that the metal pad 4 is completely confined in the worm gear 2, preventing both axial linear movement and axial rotation. This ensures that the metal pad is tightly engaged with the end of the worm gear, guaranteeing that the metal pad will not detach from the worm when the worm rotates relative to the output shaft, thus ensuring the stability of the integrated structure of the worm gear and metal pad.

[0047] In this embodiment, the metal pad 4 adopts a planar structure, which makes processing more convenient. However, when the metal pad 4 and the worm gear 2 are integrally injection molded, the metal pad 4 needs to be placed closer to the middle of the worm gear 2, making the mold design more complex. At the same time, the worm gear 2 needs to be longer axially.

[0048] Example 5 In this embodiment, the assembly method is similar to that of Embodiment 1, such as... Figure 10 , Figure 11 and Figure 12 As shown, a clamping ring 22 is integrally machined on the side of the worm gear 2 away from the metal pad 4. In this embodiment, the clamping ring 22 is integrally injection molded with the main body of the worm gear 2 and then machined. An assembly cavity 23 with a diameter larger than the diameter of the corresponding output shaft 1 assembly position is machined in the middle of the clamping ring 22. The clamping ring 22 of the worm gear 2 is clamped and assembled with the side of the sprocket 5. A clutch housing 7 is assembled on the other side of the sprocket 5. An assembly bushing 71 extending into the assembly cavity of the worm gear 2 is machined in the middle of the clutch housing 7. The assembly bushing 71 is externally connected to the sprocket 5 and the assembly cavity 23 via a spline 72. A spline groove 231 corresponding to the external spline 72 of the assembly bushing 71 is designed inside the assembly cavity 23. The end of the assembly bushing 71 has a gap from the inner wall of the assembly cavity 23.

[0049] In this embodiment, the pressure ring 22, integrally designed on the worm gear 2, is thicker than traditional protective rings, facilitating its clamping assembly with the sprocket 5. Simultaneously, it is connected to the sprocket 5 and worm gear 2 via the external spline 72 of the mounting sleeve 71 of the clutch housing 7, ensuring synchronous transmission between the sprocket 5 and worm gear 2. This completely prevents relative rotation between the worm gear 2 and sprocket 5 in the event of sprocket 5 jamming. This results in relative friction only at the metal pad 4, effectively reducing wear. Because the pressure ring 22 is located on the outer side of the sprocket, a certain degree of elastic compression is generated, making the sprocket 5 more stable when mounted on the output shaft via the worm gear.

[0050] The worm gear 2 is pressed against the clamping ring 22 by the sprocket 5, so that the worm gear 2 is further pressed against the shoulder 11. In the specific design, the outer diameter of the clamping ring 22 is between 1.4 and 2 times the outer diameter of the worm gear 2, the outer diameter of the assembly cavity is 0.9 to 1.1 times the outer diameter of the worm gear, the thickness of the clamping ring 22 is between 4.5 and 6.5 mm, and the clamping ring 22 is connected to the body of the worm gear 2 through a narrow edge.

[0051] The clamping ring 22 and the worm 2 are connected by a narrowing edge, so that when the end face of the sprocket 5 presses against the protective ring, the clamping ring 22 and the worm 2 can generate greater elastic compression through the narrow edge. In this way, even if there is slight wear at the end of the worm 2, stable clamping can still be guaranteed.

[0052] Furthermore, such as Figure 10 , Figure 11 , Figure 12As shown, a protective shell 6 is fitted on the outer side of the worm gear 3 and the worm 2. The protective shell 6 is located inside the clamping ring 22. The protective shell 6 has a protruding ring 61 on the outer annular surface of the clamping ring 22. The outer diameter of the clamping ring 22 is larger than the clamping surface of the sprocket 5. An annular groove 221 is machined on the outer ring of the clamping ring 22 corresponding to the sprocket 5. A spacer ring 62 extending inward is fitted on the protruding ring 61. The inner side of the spacer ring 62 is inserted into the spacer groove 221. A tortuous annular connecting cavity is formed between the spacer ring 62, the protruding ring 61 and the outer side of the clamping ring 22.

[0053] The aforementioned structure creates a tortuous annular connecting cavity between the spacer ring 62, the convex ring 61, and the outer side of the clamping ring 22. This ensures complete separation between the protective shell 6 and the worm gear 2, allowing for smoother rotation of the worm gear 2 along its axis inside the protective shell 6 during chainsaw operation. The more tortuous connecting cavity also prevents sawdust generated at the sprocket position from entering the worm gear connection point, thus extending the equipment's lifespan. Furthermore, this structure is highly similar to the original structure, requiring only minor modifications to parts, making implementation convenient and preserving the original design to a greater extent while reducing implementation costs.

[0054] Although embodiments of the invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions and alterations can be made to these embodiments without departing from the principles and spirit of the invention, the scope of which is defined by the appended claims and their equivalents.

Claims

1. A nylon worm gear gasket clamping structure for a chainsaw, comprising a worm gear (2) mounted on the output shaft (1) of the chainsaw, wherein the worm gear (2) outputs power to the working end of the chainsaw's oil pump via a worm wheel (3), the worm gear (2) being made of plastic and the worm wheel (3) being made of metal; the worm gear (2) is fitted onto the output shaft (1) through a central mounting hole (21), and both sides of the worm gear (2) are clamped onto the output shaft (1); characterized in that: The end of the worm (2) is designed with a metal pad (4). The metal pad (4) and the worm (2) are injection molded together. The metal pad (4) has a through hole (41) with the same size as the mounting hole (21) on the worm (2). The through hole (41) and the mounting hole (21) are coaxially assembled. The worm (2) is pressed against the output shaft (1) by the metal pad (4).

2. The nylon worm gear washer clamping structure for a chainsaw according to claim 1, characterized in that: The output shaft (1) is designed with a shoulder (11), and the worm gear (2) is clamped to the shoulder (11) of the output shaft (1) by the metal pad (4).

3. The nylon worm gear washer clamping structure for a chainsaw according to claim 1, characterized in that: The worm gear (2) is made of nylon, and the metal pad (4) is made of stainless steel; the metal pad (4) is formed by stamping.

4. A nylon worm gear washer clamping structure for a chainsaw according to any one of claims 1-3, characterized in that: The metal pad (4) is annular, and its outer ring is processed with anti-slip texture (42).

5. A nylon worm gear washer clamping structure for a chainsaw according to any one of claims 1-3, characterized in that: The outer ring of the metal pad (4) is uniformly designed with two or more integrally extended buckles (43), and the buckles (43) are bent backward and extended relative to the metal pad (4).

6. The nylon worm gear washer clamping structure for a chainsaw according to claim 5, characterized in that: The rearwardly extending end of the buckle (43) has a protrusion (44) that engages with the inside of the worm (2).

7. The nylon worm gear washer clamping structure for a chainsaw according to claim 6, characterized in that: The length of the backward extension of the buckle (43) is more than 1 / 2 of the axial length of the worm gear (2).

8. The nylon worm gear washer clamping structure for a chainsaw according to claim 1, characterized in that: The outer ring of the metal pad (4) is designed with an integrally extended buckle (45) on the same plane. The end of the worm gear that assembles the metal pad is designed with an assembly groove (24). The metal pad is assembled in the assembly groove (46). The buckle (45) of the outer ring of the metal pad (4) is inserted into the circumferential wall of the assembly groove (46). The depth of the assembly groove (46) is greater than the thickness of the metal pad (4). The end side of the worm gear (2) that assembles the metal pad (4) in the assembly groove (46) protrudes inward relative to the metal pad (4).

9. A nylon worm gear washer clamping structure for a chainsaw according to any one of claims 1-3, characterized in that: The worm gear (2) has a clamping ring (22) integrally machined on the side away from the metal pad (4). The clamping ring (22) has an assembly cavity (23) with a diameter larger than the diameter of the shaft at the corresponding output shaft (1) assembly position. The clamping ring (22) of the worm gear (2) is clamped and assembled with the side of the sprocket (5). The other side of the sprocket (5) is equipped with a clutch housing (7). The clutch housing (7) has an assembly bushing (71) extending into the assembly cavity of the worm gear (2). The assembly bushing (71) is connected to the sprocket (5) and the assembly cavity (23) via a spline (72). The assembly cavity (23) has a spline groove (231) corresponding to the spline (72) on the outside of the assembly bushing (71). The end of the assembly bushing (71) has a gap from the inner wall of the assembly cavity (23).

10. A nylon worm gear washer clamping structure for a chainsaw according to claim 9, characterized in that: The worm gear (3) and worm (2) are fitted with a protective shell (6) on their outer sides. The protective shell (6) is located inside the clamping ring (22). The protective shell (6) has a protruding ring (61) on the outer ring surface of the clamping ring (22). The outer diameter of the clamping ring (22) is larger than the clamping surface of the sprocket (5). The outer ring of the clamping ring (22) on the side corresponding to the sprocket (5) is machined with an annular groove (221). The protruding ring (61) is fitted with a spacer ring (62) extending inward. The inner side of the spacer ring (62) is inserted into the spacer groove (221). The spacer ring (62), the protruding ring (61) and the outer side of the clamping ring (22) form a tortuous annular connecting cavity.

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