CN111186560A

CN111186560A - Propeller speed limiter

Info

Publication number: CN111186560A
Application number: CN201911208417.6A
Authority: CN
Inventors: 陈双双; 郝丽; 张鹤方; 王春慧
Original assignee: AVIC Huiyang Aviation Propeller Co Ltd
Current assignee: AVIC Huiyang Aviation Propeller Co Ltd
Priority date: 2019-11-30
Filing date: 2019-11-30
Publication date: 2020-05-22

Abstract

The invention discloses a propeller speed limiter.A transmission shaft is connected in a small-diameter hole of a shell in a sliding way through a bush, two L-shaped balance weights positioned in the large-diameter hole of the shell are arranged at the upper end of the transmission shaft, an oil distribution valve is assembled in a central hole of the transmission shaft in a sliding way, and the upper end part of the oil distribution valve is pressed with a speed limiting spring; the two L-shaped counterweight and the two hook parts are propped against the bearing outer ring; the lower end of the cover is fixed on the upper end surface of the shell, the internal thread of the small hole is locked and fixed with an adjusting screw, and the adjusting plunger is assembled with the guide plate and the speed-limiting spring seat and is arranged in the cylindrical large hole of the cover; an oil dividing hole communicated with a shell lubricating oil inlet hole and an oil return hole I communicated with an oil return hole II of the shell are formed in the transmission shaft; the oil separating valve is provided with an annular oil groove II, and the annular oil groove II is not communicated or communicated with the annular oil groove I through the movement of the oil separating valve. The propeller rotating speed control method is accurate and rapid in propeller rotating speed control, prevents the phenomenon of flying rotation when the propeller is in failure, and enables the flying safety coefficient to be higher.

Description

Propeller speed limiter

Technical Field

The invention relates to a propeller speed limiter.

Background

With the development of aviation propeller technology, the requirements on a propeller control system are higher and higher. In order to ensure flight safety and prevent the propeller from flying when in fault, a propeller control system is provided with a highest rotating speed limiting mechanism, some speed limiting mechanisms are contained in an engine or a propeller structure, and sometimes, because the space structures of the engine and the propeller are limited or the requirements of functional modularization are met, the speed limiting function can be independent and designed as an independent product. The existing speed limiter is electrically controlled or hydraulic, has a simple structure, a single function, low reliability, low response speed and low regulation precision, and can not prevent the propeller from flying when the propeller breaks down once the existing speed limiter breaks down, thereby causing flight accidents. Therefore, it is very important to research a propeller speed limiter which has accurate and quick control of the rotating speed of the propeller and enables the flight safety coefficient to be higher.

Disclosure of Invention

The invention aims to solve the problems in the prior art and provide the propeller speed limiter which has the advantages that the propeller speed is controlled accurately and quickly, the phenomenon of flying rotation when the propeller breaks down is prevented, and the flying safety coefficient is higher.

In order to achieve the purpose, the technical solution of the invention is as follows: a propeller speed limiter comprises a shell, a cover, a transmission shaft, an oil distribution valve, a bushing, two L-shaped balance weights, a U-shaped balance weight disc, a bearing, a speed limiting spring, an adjusting plunger, a speed limiting spring seat, a guide plate, a locking nut, an adjusting spring seat, an adjusting spring and an adjusting screw, wherein one end of the adjusting screw is provided with a nut, a middle reducing polish rod and the other end of the adjusting screw is provided with a thread; when in use, the lower end of the shell is fixed on the mounting seat of the engine. The center of the shell is provided with a diameter-variable hole, the large-diameter hole at the upper end part is an installation hole of two L-shaped balance weights, the small-diameter hole at the lower end part is in interference fit with the bushing, and the bushing is assembled in the small-diameter hole of the shell in an interference fit manner; the transmission shaft is rotatably arranged in the bushing, a small gap between a boss flange at the upper end of the transmission shaft and the bottom surface of a large-diameter hole of the shell is lapped, an annular oil groove I is formed in the middle position of the outer circle of the transmission shaft, a center hole is formed in the center of the annular oil groove I, 2 oil distribution windows are formed in the wall of the annular oil groove I, an external spline matched with an internal spline of an engine output shaft is machined at the bottom end of the annular oil groove I, and a plurality of oil return holes I communicated with oil return holes II formed in the bottom of the shell are formed in the wall of the upper portion, close to the; when in use, the lower end of the transmission shaft is arranged on an internal spline of an engine output shaft and is driven to rotate by the engine transmission mechanism; the lower end part of the shell and the bush are provided with lubricating oil inlet holes communicated with the annular oil groove I; when the propeller is used, the lubricating oil inlet hole is connected with an oil inlet hole of an engine mounting seat, pressure lubricating oil in a propeller cavity can be introduced, and the oil return hole II is communicated with an oil return box of the engine; the oil distribution valve is slidably assembled in a center hole of the transmission shaft, the lower end part of the oil distribution valve is provided with an annular oil groove II, the upper end of the oil distribution valve is fixed on an inner ring of the bearing, when the oil distribution valve is static, the large-diameter part at the upper end of the annular oil groove II seals an oil distribution window on the transmission shaft, and when the oil distribution valve moves upwards, the annular oil groove II is communicated with an annular oil groove I on the transmission shaft through the oil; the U-shaped counterweight plate is assembled on a shaft head at the upper end of the transmission shaft in a micro-gap manner; the lower ends of the two L-shaped balance weights are hinged at the two ends of the U-shaped balance weight disc, and the two hook parts of the two L-shaped balance weights are propped against the bottom surface of the bearing outer ring; the upper end of the cover is provided with a small hole, the lower end of the cover is provided with a cylindrical large hole, the bottom surface of the cover extends outwards to form an annular connecting boss, the annular connecting boss is fixedly arranged on the upper end surface of the shell, and a self-locking thread or a self-locking steel wire thread sleeve is arranged in the small hole; the upper end of the adjusting plunger is a hollow cylinder with a bottom surface, the height of the upper end of the adjusting plunger is smaller than that of the large cylinder hole of the cover, the diameter of the upper end of the adjusting plunger is matched with that of the large cylinder hole, the lower end of the adjusting plunger extends into a reducing round rod, the cylinder at the upper end of the adjusting plunger is slidably connected into the large cylinder hole of the cover, and the center of the; the guide plate is slidably assembled on a diameter-variable round rod of the adjusting plunger, and the excircle of the guide plate is hermetically fixed at the end part of the cylindrical large hole by a step covering the cylindrical large hole, an elastic retainer ring and a sealing ring which are clamped and fixed on the wall of the cylindrical large hole; the speed-limiting spring seat is clamped and positioned at the end part of the reducing round rod of the adjusting plunger; the speed-limiting spring is arranged between the end surface of the boss of the shaft head of the oil distributing valve and the speed-limiting spring seat; the adjusting spring seat is in a shape like a Chinese character 'ji' with a central hole, the lower end of the adjusting spring seat is pressed on the hollow bottom wall of the cylinder at the upper end of the adjusting plunger by the adjusting spring, and the central hole of the upper end wall of the adjusting spring seat penetrates through the nut end of the adjusting screw; the nut of the adjusting screw is tensioned on the end face in the n-shaped concave cavity of the adjusting spring seat, the other end with threads is in threaded connection with the small hole at the upper end of the cover, the thick diameter part of the polished rod is movably and hermetically connected with the lower part of the small hole of the cover, and the upper end face of the polished rod is provided with a clamping groove of a screwing tool or a screwing handle; the lower end of the adjusting spring is arranged on the adjusting spring seat, and the upper end of the adjusting spring is limited on the top wall of the large hole of the cover cylinder.

Further preferably, the invention also comprises an electromagnetic switch I, wherein the electromagnetic switch I is fixed on the side wall of the shell; and a lubricating oil inlet hole at the lower end part of the shell is connected with an oil return hole II formed in the bottom of the shell through an electromagnetic switch I. When the electromagnetic switch I is switched on, pressure lubricating oil in the propeller cavity flows to an oil return box of the engine through the electromagnetic switch I, the pressure of the lubricating oil in the propeller cavity is reduced, and the propeller is extended to a feathering position, so that the embodiment has a feathering function.

Further preferably, the invention further comprises an electromagnetic switch II, and an oil inlet hole at the lower end part of the shell is connected with an oil cavity between the bottom surface of the hollow cylinder of the adjusting plunger and the guide plate through the electromagnetic switch II and a radial oil inlet hole formed on the cover. When the electromagnetic switch II is switched on, pressure lubricating oil in the propeller cavity flows to the lubricating oil cavity through the electromagnetic switch II, the plunger is adjusted to move upwards, and the speed limiting spring is loosened, so that the speed limiter disclosed by the invention can be used for checking whether a speed limiting system is normal or not at 91% of working rotating speed, and the rotating speed control of ground checking and trial run is realized. The speed limiter can check whether the function of the whole speed limiting module is normal or not under the condition that the speed limiter is lower than the normal working rotating speed, so that the speed limiter has the ground checking function.

Further preferably, an oil return hole II formed in the bottom of the shell is parallel to the horizontal axis, and an oil inlet hole formed in the lower end of the shell forms an angle of 30 degrees with the vertical axis. The oil flow is more convenient.

Further preferably, the upper end of the adjusting plunger is provided with a lubricating groove on the outer circle of the hollow cylinder with the bottom surface. When the oil-filled type oil-filled pump works, the lubricating groove is filled with lubricating oil, and the lubricating effect is achieved on the adjusting plunger.

Further preferably, the structure that the speed-limiting spring seat is clamped and positioned on the diameter-variable round rod of the adjusting plunger is as follows: the speed-limiting spring seat is clamped on the reducing round rod of the adjusting plunger and is locked and fixed on the reducing round rod by a self-locking nut fixed at the end part of the reducing round rod through threads, and the distance between the speed-limiting spring seat and the bottom surface of the hollow cylinder of the adjusting plunger is larger than the thickness of the guide plate.

Further preferably, the assembly structure of the U-shaped counterweight plate, the two L-shaped counterweights and the transmission shaft is: the center hole of the U-shaped counterweight plate is assembled on a shaft head at the upper end of the transmission shaft in a micro-gap manner and is blocked by a baffle plate on the shaft plate; the two L-shaped balance weights are provided with mounting holes which are respectively matched with the mounting holes at the two ends of the U-shaped balance weight disc and are hinged by a pin shaft.

When the propeller is in a normal rotating speed state, the position of the oil distribution valve in the transmission shaft hole is adjusted by the adjusting screw, the component force exerted on the oil distribution valve by the centrifugal force generated by the rotation of the L-shaped balance weight is balanced with the elastic force of the speed limiting spring, the oil distribution hole in the transmission shaft is sealed at the large diameter part at the upper end of the annular oil groove II of the oil distribution valve, high-pressure lubricating oil from the propeller cavity is blocked, and the rotating speed of the propeller is in a normal working state. When the rotating speed of the propeller rises, the L-shaped balance weight increases centrifugal force due to the rising of the rotating speed and exceeds the spring force of a set speed limiting spring, so that the oil distribution valve is lifted upwards, the annular oil groove I on the transmission shaft is communicated with the annular oil groove II of the valve, pressure lubricating oil flows into the annular oil groove I through the oil distribution hole on the transmission shaft and flows to an oil return hole of the transmission shaft through the annular oil groove II to reach an oil return box of an engine, the lubricating oil pressure in a propeller cavity is reduced, the propeller is lengthened, the rotating speed of the propeller does not rise any more, the centrifugal force of the L-shaped balance weight is reduced, component force applied to the oil distribution valve is correspondingly reduced, the oil distribution valve moves downwards until the oil distribution hole on the transmission shaft is closed again, and the rotating speed.

The propeller rotating speed control method is accurate and rapid in propeller rotating speed control, prevents the phenomenon of flying rotation when the propeller is in failure, and enables the flying safety coefficient to be higher. Particularly, the invention additionally provided with the electromagnetic switch I also has a feathering function; the invention additionally provided with the electromagnetic switch II also has a ground inspection function; the invention realizes multiple functions.

Drawings

FIG. 1 is a schematic structural view of the present invention;

FIG. 2 is a schematic diagram of the structure of the present invention;

FIG. 3 is a schematic view of a connecting structure of an adjusting plunger, a guide plate, a speed-limiting spring seat and a lock nut in the invention;

FIG. 4 is a schematic diagram of the exploded structure of FIG. 3;

FIG. 5 is a schematic view of a connecting structure of a transmission shaft and a shaft disc according to the present invention;

FIG. 6 is a schematic diagram of the exploded structure of FIG. 5;

FIG. 7 is a schematic view of the connection structure of the U-shaped balance weight plate and two L-shaped balance weights in the present invention;

fig. 8 is a schematic diagram of the exploded structure of fig. 7.

Detailed Description

The invention is further described with reference to the following figures and specific embodiments.

As shown in fig. 1 to 8, the present embodiment includes a housing 17, a cover 16, a transmission shaft 8, an oil distributing valve 10, a bushing 9, two L-shaped weights 7, a U-shaped weight plate 13, a bearing 6, a speed limiting spring 5, an adjusting plunger 4, a speed limiting spring seat 14, a guide plate 26, a lock nut 30, an adjusting spring seat 3, an adjusting spring 2, and an adjusting screw 1. When in use, the lower end of the housing 17 is fixed on the mounting seat of the engine. The center of the shell 17 is provided with a diameter-variable hole, a large-diameter hole 18 at the upper end part is a mounting hole of the two L-shaped balance weights 7, a small-diameter hole at the lower end part is in interference fit with the bushing 9, and the bushing 9 is in interference fit in the small-diameter hole of the shell 17. The transmission shaft 8 is rotatably installed in the bush 9, a shaft disc 29 with a baffle 35 fixed at the upper end is in close clearance lap joint with the bottom surface of a large-diameter hole 18 of the shell 17, an annular oil groove I19 is formed in the middle position of the outer circle of the transmission shaft, a center hole is formed in the center of the transmission shaft, 2 oil distributing windows 21 are uniformly formed in the wall of the annular oil groove I19, an external spline matched with an internal spline of an engine output shaft is machined at the bottom end of the transmission shaft, and 6 oil return holes I24 communicated with an oil return hole II formed in the bottom of the shell 17 are uniformly formed in the upper wall of the transmission shaft close to the external spline. When in use, the lower end of the transmission shaft 8 is arranged on an output shaft of the engine and is driven to rotate by the transmission mechanism of the engine. The lower end of the housing 17 and the bush 9 are provided with oil inlet holes 22 communicating with the oil ring groove I19. Preferably, the oil return hole ii formed at the bottom of the housing 17 is parallel to the horizontal axis, and the oil inlet hole 22 formed at the lower end thereof forms an angle of 30 ° with the vertical axis. When the propeller is used, the lubricating oil inlet hole 22 is connected with an oil inlet hole of an engine mounting seat, pressure lubricating oil 23 in a propeller cavity can be introduced, and the oil return hole II is communicated with an oil return box of the engine. The oil distributing valve 10 is slidably assembled in a central hole of the transmission shaft 8, the lower end part of the oil distributing valve is provided with an annular oil groove II 20, the upper end part of the oil distributing valve is fixed on an inner ring of the bearing 6, when the oil distributing valve is static, the large-diameter part at the upper end of the annular oil groove II 20 seals an oil distributing hole 21 on the transmission shaft 8, and when the oil distributing valve moves upwards, the annular oil groove II is communicated with an annular oil groove I19 on the transmission shaft 8 through. The speed limiting spring 5 is sleeved and pressed on a boss 15 at the upper end of the oil distribution valve 10, and is pressed and connected on the upper end of an inner ring of the bearing 6 by a locking nut locked at the upper end of the oil distribution valve 10. A central hole micro-gap of the U-shaped counterweight plate 13 is assembled on a shaft head at the upper end of the transmission shaft 8 and is shifted by a baffle 35 on the shaft plate 29; the two L-shaped balance weights 7 are provided with mounting holes which are respectively matched with the mounting holes at the two ends of the U-shaped balance weight disc 13 and are hinged by a pin shaft 25, and two hook parts of the two L-shaped balance weights are propped against the bottom surface of the outer ring of the bearing 6. The upper end of the cover 16 is provided with a small hole, the lower end of the cover is provided with a cylindrical large hole, the bottom surface of the cover outwards extends out of an annular connecting boss, the annular connecting boss is fixedly arranged on the upper end surface of the shell 17 through 6 uniformly distributed round head screws, and a tailless self-locking steel wire thread sleeve 32 is arranged in the small hole. The upper end of the adjusting plunger 4 is a hollow cylinder which is lower than the height of the large cylindrical hole of the cover 16, the diameter of the adjusting plunger is matched with the large cylindrical hole, a lubricating groove 34 is arranged on the outer circle of the adjusting plunger, the hollow cylinder is provided with a bottom surface, the lower end of the adjusting plunger extends into a variable diameter round rod, the upper end of the adjusting plunger is slidably connected in the large cylindrical hole of the cover 16, and the center of the adjusting plunger is provided. The guide plate 26 is slidably assembled on the reducing round rod of the adjusting plunger 4, and the outer circle of the guide plate is sealed and fixed on the end part of the cylindrical large hole by a step in the cylindrical large hole of the cover 16, an elastic retainer ring 31 and an O-shaped sealing ring which are clamped and fixed on the wall of the cylindrical large hole. The speed-limiting spring seat 14 is clamped on the diameter-variable round rod of the adjusting plunger 4 and is locked and fixed on the diameter-variable round rod by a self-locking nut 30 fixed at the end part of the diameter-variable round rod through threads, and the distance between the speed-limiting spring seat and the bottom surface of the hollow cylinder of the adjusting plunger 4 is larger than the thickness of the guide plate 26. The speed limiting spring 5 is arranged between the end surface of a shaft head boss 15 of the oil distributing valve 10 and the speed limiting spring seat 14. The adjusting spring seat 3 is in a shape of a Chinese character 'ji' with a central hole, the lower end of the adjusting spring seat is pressed on the cylindrical hollow bottom wall at the upper end of the adjusting plunger 4 by the adjusting spring 2, the central hole of the upper end wall of the adjusting spring is penetrated at the nut end of the adjusting screw 1, the lower end of the adjusting spring 2 is placed on the adjusting spring seat 3, and the upper end of the adjusting spring is limited on the top wall of the cylindrical large hole of the. The nut of the adjusting screw 1 is tightened on the end face in the n-shaped concave cavity of the adjusting spring seat 3, the other end with threads is in threaded connection with a tailless self-locking steel wire thread sleeve 32 in a small hole at the upper end of the cover 16 (or can be directly fixed in the small hole with threads), a sealing ring groove is arranged at the thick diameter part of a polished rod, the O-shaped sealing ring is movably and hermetically connected with the lower part of the small hole of the cover 16, and a clamping groove of a screwing tool or a screwing handle is arranged on the upper end face of the polished rod; the clamping groove of the embodiment is an insertion hole of a hexagonal wrench.

Preferably, the present embodiment further comprises an electromagnetic switch i 12, wherein the electromagnetic switch i 12 is fixed on a side wall of the housing 16; the lubricating oil inlet hole 22 at the lower end part of the shell 17 is connected with an oil return hole II formed at the bottom part of the shell 17 through an electromagnetic switch I12. When the electromagnetic switch I12 is switched on, pressure lubricating oil 23 in the propeller cavity flows to an oil return tank of the engine through the electromagnetic switch I12, the pressure of the lubricating oil in the propeller cavity is reduced, and the propeller is extended to a feathering position, so that the embodiment has a feathering function.

Preferably, the present embodiment further comprises an electromagnetic switch ii 11, and the oil inlet hole 22 at the lower end of the housing 17 is connected to an oil cavity 28 between the bottom surface of the hollow cylinder of the adjustment plunger 4 and the guide plate 26 through the electromagnetic switch ii 11 and a radial oil inlet hole 27 formed in the cover 16. When the electromagnetic switch II 11 is switched on, pressure lubricating oil 23 in the propeller cavity flows to the lubricating oil cavity 28 through the electromagnetic switch II 11, the plunger 4 is adjusted to move upwards, and the speed limiting spring 5 is loosened, so that the speed limiter provided by the invention can check whether a speed limiting system is normal or not at 91% of the working speed, and the speed control of ground inspection and test run is realized. The speed limiter can check whether the function of the whole speed limiting module is normal or not under the condition that the speed limiter is lower than the normal working rotating speed, so that the speed limiter has the ground checking function.

There are, of course, many other embodiments of the invention and modifications and variations of this invention that will be obvious to those skilled in the art may be made without departing from the spirit and scope of the invention, but it is intended to cover all such modifications and variations as fall within the true spirit and scope of the invention.

Claims

1. A propeller speed limiter characterized by: the oil distribution device comprises a shell, a cover, a transmission shaft, an oil distribution valve, a bushing, two L-shaped counterweights, a U-shaped counterweight plate, a bearing, a speed limiting spring, an adjusting plunger, a speed limiting spring seat, a guide plate, a locking nut, an adjusting spring seat, an adjusting spring and an adjusting screw, wherein one end of the adjusting screw is provided with a nut, a middle reducing polish rod and the other end of the adjusting screw is provided with threads; the center of the shell is provided with a diameter-variable hole, the large-diameter hole at the upper end part is an installation hole of two L-shaped balance weights, the small-diameter hole at the lower end part is in interference fit with the bushing, and the bushing is assembled in the small-diameter hole of the shell in an interference fit manner; the transmission shaft is rotatably arranged in the bushing, a small gap between a boss flange at the upper end of the transmission shaft and the bottom surface of a large-diameter hole of the shell is lapped, an annular oil groove I is formed in the middle position of the outer circle of the transmission shaft, a center hole is formed in the center of the annular oil groove I, 2 oil distribution windows are formed in the wall of the annular oil groove I, an external spline matched with an internal spline of an engine output shaft is machined at the bottom end of the annular oil groove I, and a plurality of oil return holes I communicated with oil return holes II formed in the bottom of the shell are formed in the wall of the upper portion, close to the; the lower end part of the shell and the bush are provided with lubricating oil inlet holes communicated with the annular oil groove I; the oil distribution valve is slidably assembled in a center hole of the transmission shaft, the lower end part of the oil distribution valve is provided with an annular oil groove II, the upper end of the oil distribution valve is fixed on an inner ring of the bearing, when the oil distribution valve is static, the large-diameter part at the upper end of the annular oil groove II seals an oil distribution window on the transmission shaft, and when the oil distribution valve moves upwards, the annular oil groove II is communicated with an annular oil groove I on the transmission shaft through the oil; the U-shaped counterweight plate is assembled on a shaft head at the upper end of the transmission shaft in a micro-gap manner; the lower ends of the two L-shaped balance weights are hinged at the two ends of the U-shaped balance weight disc, and the two hook parts of the two L-shaped balance weights are propped against the bottom surface of the bearing outer ring; the upper end of the cover is provided with a small hole, the lower end of the cover is provided with a cylindrical large hole, the bottom surface of the cover extends outwards to form an annular connecting boss, the annular connecting boss is fixedly arranged on the upper end surface of the shell, and a self-locking thread or a self-locking steel wire thread sleeve is arranged in the small hole; the upper end of the adjusting plunger is a hollow cylinder with a bottom surface, the height of the upper end of the adjusting plunger is smaller than that of the large cylinder hole of the cover, the diameter of the upper end of the adjusting plunger is matched with that of the large cylinder hole, the lower end of the adjusting plunger extends into a reducing round rod, the cylinder at the upper end of the adjusting plunger is slidably connected into the large cylinder hole of the cover, and the center of the; the guide plate is slidably assembled on a diameter-variable round rod of the adjusting plunger, and the excircle of the guide plate is hermetically fixed at the end part of the cylindrical large hole by a step covering the cylindrical large hole, an elastic retainer ring and a sealing ring which are clamped and fixed on the wall of the cylindrical large hole; the speed-limiting spring seat is clamped and positioned at the end part of the reducing round rod of the adjusting plunger; the speed-limiting spring is arranged between the end surface of the boss of the shaft head of the oil distributing valve and the speed-limiting spring seat; the adjusting spring seat is in a shape like a Chinese character 'ji' with a central hole, the lower end of the adjusting spring seat is pressed on the hollow bottom wall of the cylinder at the upper end of the adjusting plunger by the adjusting spring, and the central hole of the upper end wall of the adjusting spring seat penetrates through the nut end of the adjusting screw; the nut of the adjusting screw is tensioned on the end face in the n-shaped concave cavity of the adjusting spring seat, the other end with threads is in threaded connection with the small hole at the upper end of the cover, the thick diameter part of the polished rod is movably and hermetically connected with the lower part of the small hole of the cover, and the upper end face of the polished rod is provided with a clamping groove of a screwing tool or a screwing handle; the lower end of the adjusting spring is arranged on the adjusting spring seat, and the upper end of the adjusting spring is limited on the top wall of the large hole of the cover cylinder.

2. The propeller governor of claim 1, wherein: the electromagnetic switch I is fixed on the side wall of the shell; and a lubricating oil inlet hole at the lower end part of the shell is connected with an oil return hole II formed in the bottom of the shell through an electromagnetic switch I.

3. A propeller speed limiter according to claim 1 or claim 2, wherein: the lubricating oil inlet hole at the lower end part of the shell is connected with a lubricating oil cavity between the bottom surface of the hollow cylinder of the adjusting plunger and the guide plate through the electromagnetic switch II and a radial oil inlet hole formed in the cover.

4. The propeller governor of claim 3, wherein: an oil return hole II formed in the bottom of the shell is parallel to the horizontal axis, and a lubricating oil inlet hole formed in the lower end of the shell forms an angle of 30 degrees with the vertical axis.

5. The propeller governor of claim 4, wherein: and a lubricating groove is formed on the outer circle of the hollow cylinder with the bottom surface at the upper end of the adjusting plunger.

6. The propeller governor of claim 5, wherein: the structure that the speed-limiting spring seat is clamped and positioned on the reducing round rod of the adjusting plunger is as follows: the speed-limiting spring seat is clamped on the reducing round rod of the adjusting plunger and is locked and fixed on the reducing round rod by a self-locking nut fixed at the end part of the reducing round rod through threads, and the distance between the speed-limiting spring seat and the bottom surface of the hollow cylinder of the adjusting plunger is larger than the thickness of the guide plate.

7. The propeller governor of claim 6, wherein: the assembly structure of U type counterweight plate, two L type counter weights and transmission shaft is: the center hole of the U-shaped counterweight plate is assembled on a shaft head at the upper end of the transmission shaft in a micro-gap manner and is blocked by a baffle plate on the shaft plate; the two L-shaped balance weights are provided with mounting holes which are respectively matched with the mounting holes at the two ends of the U-shaped balance weight disc and are hinged by a pin shaft.

8. A propeller speed limiter according to claim 1 or claim 2, wherein: an oil return hole II formed in the bottom of the shell is parallel to the horizontal axis, and a lubricating oil inlet hole formed in the lower end of the shell forms an angle of 30 degrees with the vertical axis; and a lubricating groove is formed on the outer circle of the hollow cylinder with the bottom surface at the upper end of the adjusting plunger.

9. A propeller speed limiter according to claim 1 or claim 2, wherein: the structure that the speed-limiting spring seat is clamped and positioned on the reducing round rod of the adjusting plunger is as follows: the speed-limiting spring seat is clamped on the reducing round rod of the adjusting plunger and is locked and fixed on the reducing round rod by a self-locking nut fixed at the end part of the reducing round rod through threads, and the distance between the speed-limiting spring seat and the bottom surface of the hollow cylinder of the adjusting plunger is larger than the thickness of the guide plate.

10. A propeller speed limiter according to claim 1 or claim 2, wherein: the assembly structure of U type counterweight plate, two L type counter weights and transmission shaft is: the center hole of the U-shaped counterweight plate is assembled on a shaft head at the upper end of the transmission shaft in a micro-gap manner and is blocked by a baffle plate on the shaft plate; the two L-shaped balance weights are provided with mounting holes which are respectively matched with the mounting holes at the two ends of the U-shaped balance weight disc and are hinged by a pin shaft.