Combined sealing structure for output shaft of marine gearbox

Abstract

The invention relates to a sealing structure, in particular to a combined sealing structure for an output shaft of a marine gearbox. The problem that an existing sealing component can cause leakage under the conditions that an output shaft is static, low in speed, large in lubricating oil amount, too large in oil pressure and the like is solved. A three-stage combined sealing structure is formed by the oil slinger, the labyrinth sealing ring and the lip-shaped sealing assembly. The oil slinger arranged on the output shaft is simple in structure, convenient to transform and good in economical efficiency. The labyrinth sealing ring not only can meet the sealing requirement of a rotating part, but also has self-adaptive flexural deflection, and can be automatically adjusted in a limited manner, so that a good sealing effect is achieved. The lip-shaped sealing assembly structurally achieves the bidirectional sealing effect, internal lubricating oil can be sealed, and water, dust, silt and other external impurities are prevented from entering the gearbox. Through the application of the combined sealing structure, leakage is reduced step by step. The invention belongs to the technical field of gearbox sealing.

Description

Technical Field

[0001] The present invention relates to a sealing structure, in particular to an output shaft combined sealing structure of a marine gear box, belonging to the technical field of gear box sealing. Background Art

[0002] Marine gearboxes are a crucial part of a ship's powertrain. Their output shaft seals are crucial for ensuring proper gearbox operation and preventing lubricant leakage. These seals are directly linked to the performance and reliability of marine gearboxes, significantly impacting their normal operation and lifespan. The primary function of a gearbox output shaft seal is to prevent lubricant leakage and prevent the ingress of foreign matter, such as dust, metal powder, sand, moisture, and other fluids, into the gearbox interior. These foreign matter can lead to an increase in lubricant particulates and a decrease in lubrication quality. Foreign matter exacerbates wear on transmission components like bearings and gears, while moisture and other fluids can impair lubrication, deteriorating the oil quality and causing wear and corrosion. Degraded oil performance weakens the oil film's strength and integrity, leading to poor lubrication and, in turn, metal fatigue damage or even cracking. Lubricant leakage can result in insufficient lubrication in transmission components like bearings and gears, resulting in under-lubrication and environmental contamination. An effective sealing structure can prevent lubricant leakage, maintain cleanliness and lubrication within the gearbox, and extend its service life.

[0003] Marine gearbox output shaft seals are primarily categorized into contact seals and non-contact seals. Currently, lip seals and labyrinth seals are the most popular seal types. Both are widely used due to their simple structure, ease of installation, and ease of replacement.

[0004] Through the long-term use of the above two seals in marine gearboxes, the reasons for the poor sealing effect of the output shaft seal are analyzed, mainly in the following aspects: First of all, the current sealing structure has limitations in its application: the two types of seals mentioned above have certain problems in actual application. The most common problems with lip seals are oil leakage and heat generation. Labyrinth seals have poor sealing performance when static, and often cause eccentric wear problems during startup. Generally speaking, lip seals have better sealing performance, but are limited by friction and accelerate aging and wear after heating. The linear speed, temperature, and internal and external pressure difference of the journal all have certain limitations on the application of lip seals. When designing, designers often pay attention to the linear speed of the journal and ignore the internal and external pressure difference of the seal. p , while the national standard stipulates that the ordinary sealing lip seal Δ pThe operating conditions for marine gearboxes are ≤0.05MPa (GB / T9877), while the rated operating pressure of most marine gearboxes is 0.15-0.3MPa. Higher linear speeds require higher injection pressures, increasing the risk of seal leakage. During use, labyrinth seals are susceptible to wear of the seal teeth due to factors such as small sealing gaps, rotor bending, and vibration, leading to increased leakage. Furthermore, while the non-contact seal design minimizes leakage, its operating principle cannot completely prevent it. This is particularly true in static conditions, at low speeds, with high lubricant volumes, and at excessive oil pressure.

[0005] There is a problem of significant axis centerline misalignment: Currently, marine propulsion shafting systems often utilize "rational alignment technology." This technology considers constraints such as load, stress, and rotational angle to distribute the load across the shafting bearings. The vertical height of each bearing is intentionally raised or lowered, resulting in a curved shafting arrangement. When operating from a static state to a running state, significant axis misalignment occurs. Existing marine gearboxes, with the exception of a few low-power gearboxes, mostly use plain bearings for their output shafts. These bearings have larger radial clearances than rolling bearings, leading to significant axis centerline variation. Furthermore, wear of these bearings can exacerbate axis misalignment. In this situation, both lip seals and labyrinth seals experience eccentric wear, exacerbating wear and compromising sealing. For example, existing research indicates that the lip seal's lip, due to contact with the shaft journal, experiences a temperature 10-20°C higher than the oil temperature. Increased tilt or eccentricity increases the lip temperature. Theoretically, a 10°C increase in temperature or a 0.1mm increase in eccentricity reduces the lifespan of a lip seal by half.

[0006] Based on the above analysis, it is very necessary to develop a reliable sealing structure for the gearbox output shaft to overcome the limitations and shortcomings of existing products and meet the needs of actual use. Summary of the Invention

[0007] In view of the above-mentioned deficiencies in the prior art, the present invention provides an output shaft combined sealing structure for a marine gearbox.

[0008] The technical solution of the present invention is: a combined sealing structure for the output shaft of a marine gearbox, including an output shaft, which is rotatably connected to a housing bearing seat through a sliding bearing, a split end cover is installed on the end face of the housing bearing seat, the output shaft passes through the housing bearing seat and the split end cover, and both the housing bearing seat and the split end cover are provided with oil drain holes, the oil drain holes are connected to the housing, a guide ring groove is provided on the end face of the split end cover facing the inside of the housing, and a pressure plate is coaxially installed on the end face of the split end cover facing the outside of the housing.

[0009] Furthermore, it also includes an oil slinger, a labyrinth seal ring, a second positioning pin and a lip seal assembly which are coaxially mounted on the output shaft in sequence.

[0010] The oil slinger ring is arranged between the sliding bearing and the split end cover, and an annular groove is formed on the outer circumference of the oil slinger ring.

[0011] The outer circumferential surface of the labyrinth sealing ring is drum-shaped and can cooperate with the spherical inner hole section of the split end cover. The labyrinth sealing ring is provided with an oil return hole which is connected to the oil drain hole.

[0012] A radial hole is opened on the split end cover, and the inner diameter of the radial hole is larger than the outer diameter of the second positioning pin.

[0013] The lower half of the second positioning pin is inserted into the labyrinth sealing ring, and the upper half of the second positioning pin is inserted into the radial hole.

[0014] The lip seal assembly consists of a lantern ring, a spacer ring, and two lip seals.

[0015] The spacer ring is arranged between the two lip sealing rings, and is provided with a first oil inlet ring groove and a first radial oil inlet hole which are communicated with each other.

[0016] Two lip seals are embedded in the collar in a back-to-back installation manner. The collar is embedded in the split end cover. The collar is axially fixed by a pressure plate.

[0017] The collar is provided with a second oil inlet ring groove and a second radial oil inlet hole which are communicated with each other, and the second radial oil inlet hole is communicated with the first oil inlet ring groove.

[0018] Annular sealing grooves are provided on both sides of the second oil inlet ring groove, in which a supporting ring and an O-ring are installed, and the inner surface of the supporting ring abuts against the O-ring, and the outer surface of the supporting ring abuts against the inner hole of the split end cover.

[0019] Compared with the prior art, the present invention has the following effects: The advantages of the present invention are: a three-stage combined sealing structure is formed by the oil slinger 100, the labyrinth seal ring 200 and the lip seal assembly 300; The oil slinger 100 provided on the output shaft has a simple structure, is easy to modify, and has good economic efficiency; The labyrinth sealing ring 200 can not only meet the sealing requirements of rotating parts, but also has adaptive flexural deformation and can automatically adjust to a limited extent to achieve a good sealing effect.

[0020] The lip seal assembly 300 generates radial compressive stress through the elastic deformation of the O-ring 305, which is compressed. This allows the inner and outer surfaces of the support ring 304 to contact the inner hole of the O-ring 305 and the split end cap 4, respectively. The sealing lip of the O-ring 305 fits tightly against the outer circumference of the output shaft 1, compensating for and absorbing any skewness of the sealing lip and shaft vibration. The two lip seals 302, mounted back-to-back, achieve a bidirectional seal, sealing the internal lubricating oil while preventing external impurities such as moisture, dust, and sand from entering the gearbox. This invention offers the advantages of a compact structure, easy disassembly, and excellent economic efficiency. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is a structural schematic diagram of the present invention; Figure 2 is an axonometric view of the oil slinger 100 of the present invention; Figure 3 is an axonometric view of the labyrinth seal ring 200 of the present invention; Figure 4 yes Figure 1 A partial enlarged view of point Ⅰ in the middle; Figure 5 yes Figure 4 A partial enlarged view of the middle II; Figure 6 FIG. 3 is a cross-sectional view of the lip seal ring 302 of the present invention.

[0022] In the figure: 1, output shaft; 2, housing bearing seat; 3, sliding bearing; 4, split end cover; 5, oil nozzle; 6, pressure plate; 100, oil slinger; 101, first semicircular ring; 102, second semicircular ring; 103, set screw; 104, first positioning pin; 105, annular groove; 200, labyrinth seal ring; 201, upper semicircular ring; 202, lower semicircular ring; 203, second positioning pin; 204, circular Pin; 205, screw; 300, lip seal assembly; 301, collar; 302, lip seal ring; 303, spacer ring; 301-1, second oil inlet ring groove; 301-2, second radial oil inlet hole; 303-1, first oil inlet ring groove; 303-2, first radial oil inlet hole; 304, support ring; 304-1, oil storage ring groove; 305, O-ring; 307, polytetrafluoroethylene resin patch. DETAILED DESCRIPTION

[0023] In order to make the purpose, features and advantages of the present invention more obvious and easy to understand, the technical solutions in the embodiments of the present invention will be clearly and completely described below with reference to the accompanying drawings in the embodiments of the present invention.

[0024] Specific implementation method 1: Combination Figures 1 to 6To illustrate this embodiment, a combined sealing structure of the output shaft of a marine gearbox in this embodiment includes an output shaft 1, which is rotatably connected to a housing bearing seat 2 through a sliding bearing 3, and a split end cover 4 is installed on the end face of the housing bearing seat 2. The output shaft 1 passes through the housing bearing seat 2 and the split end cover 4, and both the housing bearing seat 2 and the split end cover 4 are provided with oil drain holes, which are connected to the housing, and a guide ring groove is provided on the end face of the split end cover 4 facing the inside of the housing, and a pressure plate 6 is coaxially installed on the end face of the split end cover 4 facing the outside of the housing, and the pressure plate 6 is installed on the split end cover 4 by bolts.

[0025] Furthermore, it also includes an oil slinger 100, a labyrinth seal ring 200, a second positioning pin 203 and a lip seal assembly 300 coaxially installed on the output shaft 1 in sequence, and a three-stage combined sealing structure is formed by the oil slinger 100, the labyrinth seal ring 200 and the lip seal assembly 300.

[0026] The oil slinger 100 is arranged between the sliding bearing 3 and the split end cover 4 , and an annular groove 105 is formed on the outer circumferential surface of the oil slinger 100 . Furthermore, the annular groove 105 is a V-shaped annular groove.

[0027] The outer circumferential surface of the labyrinth sealing ring 200 is drum-shaped and can cooperate with the spherical inner hole section of the split end cover 4. The labyrinth sealing ring 200 is provided with an oil return hole, which is connected to the oil drain hole.

[0028] A radial hole is formed on the split end cover 4 , and the inner diameter of the radial hole is larger than the outer diameter of the second positioning pin 203 .

[0029] The lower half of the second positioning pin 203 is inserted into the labyrinth sealing ring 200 , and the upper half of the second positioning pin 203 is inserted into the radial hole.

[0030] The lip seal assembly 300 includes a collar 301 , a spacer ring 303 and two lip seal rings 302 .

[0031] The spacer ring 303 is arranged between the two lip seal rings 302 , and is provided with a first oil inlet ring groove 303 - 1 and a first radial oil inlet hole 303 - 2 which are communicated with each other.

[0032] The two lip-shaped sealing rings 302 are embedded in the ring 301 in a back-to-back installation manner. In this arrangement, the sealing lips of the two lip-shaped sealing rings 302 face the inside and outside of the box respectively. The structural design solves the problem of preventing the lubricating oil from overflowing and the entry of external impurities, and achieves a two-way sealing effect; the ring 301 is embedded in the split end cover 4, and the ring 301 is axially fixed by the pressure plate 6.

[0033] The collar 301 is provided with a second oil inlet ring groove 301 - 1 and a second radial oil inlet hole 301 - 2 which are in communication with each other. The second radial oil inlet hole 301 - 2 is in communication with the first oil inlet ring groove 303 - 1 .

[0034] Annular sealing grooves are provided on both sides of the second oil inlet ring groove 301-1, in which a support ring 304 and an O-ring 305 are installed, and the inner surface of the support ring 304 is against the O-ring 305, and the outer surface of the support ring 304 is against the inner hole of the split end cover 4. With such an arrangement, the pre-compression force generated by the elastic deformation of the O-ring 305 makes the support ring 304 and the inner hole of the split end cover 4 fit tightly together, thereby playing a sealing role.

[0035] Specific implementation method 2: Combination Figures 1 to 6 To illustrate this embodiment, the oil slinger 100 in this embodiment is a split structure, and the oil slinger 100 is fixed to the output shaft 1 by means of set screws 103 to fix the relative position of the two.

[0036] The oil slinger 100 includes a first semicircular ring 101, a second semicircular ring 102 and a first positioning pin 104. Positioning steps are integrally provided on the center dividing surfaces of the first semicircular ring 101 and the second semicircular ring 102. The first positioning pin 104 is arranged parallel to the axis of the oil slinger 100, and after the first semicircular ring 101 and the second semicircular ring 102 are connected, the first positioning pin 104 is inserted into the positioning step.

[0037] Furthermore, the labyrinth sealing ring 200 is a split structure, and the labyrinth sealing ring 200 includes an upper semicircular ring 201 , a lower semicircular ring 202 and a cylindrical pin 204 .

[0038] The cylindrical pin 204 passes through the dividing plane between the upper semicircular ring 201 and the lower semicircular ring 202 , and the upper semicircular ring 201 and the lower semicircular ring 202 are connected by screws 205 .

[0039] The lower half of the second positioning pin 203 is inserted into the upper semicircular ring 201 , and an oil return hole is opened on the lower semicircular ring 202 .

[0040] Furthermore, the upper semicircular ring 201 and the lower semicircular ring 202 are both made of copper alloy. This arrangement, on the one hand, utilizes the certain strength, wear resistance and self-lubricating properties of copper alloy to protect the output shaft 1 and can withstand a slight contact between the inner circumferential surface of the labyrinth sealing ring 200 and the output shaft 1. On the other hand, it can form a minimum gap to achieve the best sealing effect.

[0041] Other components and connection relationships are the same as those in the first embodiment.

[0042] Specific implementation method three: Combination Figures 1 to 6To illustrate this embodiment, the support ring 304 is made of polytetrafluoroethylene resin. Compared with other materials, polytetrafluoroethylene resin has corrosion resistance, good fluid compatibility, low friction coefficient, and self-lubricating properties.

[0043] Furthermore, two oil storage ring grooves 304-1 are opened on the support ring 304. Furthermore, the outer diameter of the support ring 304 and the inner diameter of the split end cover 4 are transitionally matched, and the oil storage ring groove 304-1 is located between the end face and the outer circumferential surface of the support ring 304. Such an arrangement prevents the support ring 304 from unlubricated wear, while reducing the contact area between the support ring 304 and the split end cover 4, thereby increasing the specific pressure of the sealing surface and the pressure per unit area of ​​the sealing surface, making it easier to obtain a more ideal pressure distribution and enhancing the sealing effect.

[0044] Other components and connection relationships are the same as those in the first or second embodiment.

[0045] Specific implementation method four: Combination Figures 1 to 6 To explain this embodiment, a polytetrafluoroethylene resin patch 307 is bonded to the sealing lip of the lip seal ring 302. This arrangement allows the polytetrafluoroethylene resin to withstand high temperatures and resist aging. It also offers good fluid compatibility, self-lubrication, and a low coefficient of friction, reducing wear and extending the service life of the lip seal ring 302. Other components and connections are the same as those in Specific Embodiments 1, 2, or 3.

[0046] Specific implementation method five: Combination Figures 1 to 6 To illustrate this embodiment, an oil nozzle 5 is installed on the split end cover 4 in this embodiment, and the oil nozzle 5 is connected to the second oil inlet ring groove 301-1. With this arrangement, the grease injected by the oil nozzle 5 passes through the second oil inlet ring groove 301-1, the second radial oil inlet hole 301-2, the first oil inlet ring groove 303-1 and the first radial oil inlet hole 303-2 in sequence, and then enters the grease chamber formed by the two lip seals 302 installed "back to back" to lubricate the sealing lips and reduce friction.

[0047] Other components and connection relationships are the same as those in the first, second, third or fourth embodiment.

[0048] How it works Combine Figures 1 to 6 The working principle of the present invention is described: An oil slinger 100 , a labyrinth seal ring 200 and a lip seal assembly 300 are coaxially mounted on the output shaft 1 in sequence, forming a three-stage combined sealing structure.

[0049] First, the oil slinger 100 is fixed to the output shaft 1 by means of a set screw 103 and is located between the sliding bearing 3 and the split end cover 4. When the output shaft 1 rotates, the centrifugal force is used to throw away the lubricating oil leaking from the sliding bearing 3 to the area between the housing bearing seat 2 and the split end cover 4. The annular groove 105 on the oil slinger 100 can throw away some of the lubricating oil that rebounds back again; the split end cover 4 is provided with a guide ring groove to prevent the splashing lubricating oil from falling onto the shaft surface again. After being thrown away, the oil flows back to the gearbox through the oil drain hole and continues to participate in the oil circulation. The oil slinger 100 can block most of the lubricating oil, solve the axial leakage of the lubricating oil on the shaft surface, and eliminate the hidden dangers of seal leakage at static and low speeds. In addition, the structure is simple, easy to process, manufacture and implement, and has good economic efficiency.

[0050] Secondly, since the inner circumferential surface of the labyrinth seal ring 200 is provided with a plurality of labyrinth seal grooves, a throttling effect occurs when the lubricating oil passes through the labyrinth seal grooves that cooperate with the shaft neck, generating resistance and gradually reducing pressure to achieve the purpose of leak-proof sealing; The ends of the second locating pin 203 are respectively inserted into the labyrinth seal ring 200 and the radial hole (the inner diameter of the radial hole is larger than the outer diameter of the second locating pin 203), restricting the labyrinth seal ring 200 from rotating circumferentially. The outer circumferential surface of the labyrinth seal ring 200 forms a spherical fit with the inner hole of the split end cap 4, enabling the labyrinth seal assembly to achieve limited automatic adjustment with shaft deflection and axial deflection. Lubricating oil escaping from the labyrinth seal ring 200 flows back into the gearbox through the oil return and drain holes.

[0051] Finally, the elastic deformation of the O-ring 305 compresses the lip seal assembly 300, generating radial compressive stress. This forces the inner and outer surfaces of the support ring 304 to contact the O-ring 305 and the inner bore of the split end cap 4, respectively. The sealing lip of the O-ring 305 fits tightly against the outer circumference of the output shaft 1, compensating for and absorbing any skewness of the sealing lip and shaft vibration. The two lip seals 302, mounted back-to-back, achieve a bidirectional seal, sealing the internal lubricating oil while preventing external impurities such as moisture, dust, and sand from entering the gearbox.

[0052] The combined sealing structure described above achieves progressively reduced leakage. The oil slinger 100 and labyrinth seal 200 retain the majority of the lubricating oil. The lubricating oil pressure gradually decreases through the labyrinth seal 200, and any leaking oil is supplemented by the lip seal. The intercepted lubricating oil then returns to the gearbox.

[0053] The present invention has been disclosed above with preferred embodiments, but this is not intended to limit the present invention. Any simple modifications, equivalent changes, and modifications made to the above implementation cases by any person skilled in the art without departing from the content of the technical solution of the present invention based on the technical essence of the present invention are still within the scope of the technical solution of the present invention.

Claims

1. A combined sealing structure for an output shaft of a marine gearbox, comprising an output shaft (1), the output shaft (1) being rotatably connected to a housing bearing seat (2) via a sliding bearing (3), a split end cover (4) being mounted on the end face of the housing bearing seat (2), the output shaft (1) passing through the housing bearing seat (2) and the split end cover (4), and an oil drain hole being provided on both the housing bearing seat (2) and the split end cover (4), the oil drain hole being connected to the housing, a guide ring groove being provided on the end face of the split end cover (4) facing the interior of the housing, and a pressure plate (6) being coaxially mounted on the end face of the split end cover (4) facing the exterior of the housing, wherein: It also includes an oil slinger (100), a labyrinth seal ring (200), a second positioning pin (203), and a lip seal assembly (300) coaxially mounted on the output shaft (1); The oil slinger ring (100) is arranged between the sliding bearing (3) and the split end cover (4), and an annular groove (105) is formed on the outer circumferential surface of the oil slinger ring (100); The outer circumferential surface of the labyrinth sealing ring (200) is drum-shaped and can cooperate with the spherical inner hole section of the split end cover (4). The labyrinth sealing ring (200) is provided with an oil return hole, which is connected to the oil drain hole. A radial hole is formed on the split end cover (4), and the inner diameter of the radial hole is larger than the outer diameter of the second positioning pin (203); The lower half of the second positioning pin (203) is inserted into the labyrinth sealing ring (200), and the upper half of the second positioning pin (203) is inserted into the radial hole; The lip seal assembly (300) comprises a collar (301), a spacer ring (303) and two lip seal rings (302); The spacer ring (303) is arranged between the two lip seal rings (302), and the spacer ring (303) is provided with a first oil inlet ring groove (303-1) and a first radial oil inlet hole (303-2) that are communicated with each other; Two lip seals (302) are embedded in the collar (301) in a back-to-back installation manner, the collar (301) is embedded in the split end cover (4), and the collar (301) is axially fixed by a pressure plate (6); The collar (301) is provided with a second oil inlet ring groove (301-1) and a second radial oil inlet hole (301-2) that are communicated with each other, and the second radial oil inlet hole (301-2) is communicated with the first oil inlet ring groove (303-1); Annular sealing grooves are provided on both sides of the second oil inlet ring groove (301-1), and a support ring (304) and an O-type sealing ring (305) are installed in the annular sealing groove. The inner surface of the support ring (304) abuts against the O-type sealing ring (305), and the outer surface of the support ring (304) abuts against the inner hole of the split end cover (4).

2. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: The oil slinger (100) is fixed to the output shaft (1) via a set screw (103); The oil slinger ring (100) comprises a first semicircular ring (101), a second semicircular ring (102) and a first positioning pin (104). Positioning steps are integrally provided on the mid-division surfaces of the first semicircular ring (101) and the second semicircular ring (102). The first positioning pin (104) is arranged parallel to the axis of the oil slinger ring (100). After the first semicircular ring (101) and the second semicircular ring (102) are butt-jointed, the first positioning pin (104) is inserted into the positioning step.

3. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: The labyrinth sealing ring (200) comprises an upper semicircular ring (201), a lower semicircular ring (202) and a cylindrical pin (204); The cylindrical pin (204) passes through the dividing surface between the upper semicircular ring (201) and the lower semicircular ring (202), and the upper semicircular ring (201) and the lower semicircular ring (202) are connected by screws (205); The lower half of the second positioning pin (203) is inserted into the upper semicircular ring (201), and the lower semicircular ring (202) is provided with an oil return hole.

4. The output shaft combined sealing structure of a marine gearbox according to claim 3, characterized in that: The upper semicircular ring (201) and the lower semicircular ring (202) are both made of copper alloy.

5. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: The material of the support ring (304) is polytetrafluoroethylene resin.

6. The output shaft combined sealing structure of a marine gearbox according to claim 5, characterized in that: Two oil storage ring grooves (304-1) are formed on the support ring (304).

7. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: A polytetrafluoroethylene resin patch (307) is bonded to the sealing lip of the lip-shaped sealing ring (302).

8. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: An oil nozzle (5) is mounted on the split end cover (4), and the oil nozzle (5) is in communication with the second oil inlet ring groove (301-1).

9. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: The annular groove (105) is a V-shaped annular groove.

10. The output shaft combined sealing structure of a marine gearbox according to claim 1, characterized in that: The pressure plate (6) is mounted on the split end cover (4) by means of bolts.

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