A propeller short pitch limiting mechanism in slow-speed state

Abstract

The invention discloses a propeller small pitch limit mechanism in slow-speed state, wherein a support plate is sleeved outside a propeller shell away from one end of a propeller piston and fixed on the shell, and through holes Ⅰ for pitch rods are evenly opened on the support plate; a guide sleeve assembly is sleeved and fixed in through hole Ⅰ of the support plate; a guide snap ring is fixed on the outer circle of the other end of the propeller shell; a piston boss with through hole Ⅱ for pitch rods is protruded on the propeller piston; a small pitch stop nut is fixed on the pitch rod; the pitch rod passes through through hole Ⅱ of the guide sleeve assembly, the guide snap ring and the piston boss, and is fixed on a low pitch stop ring passing outside the propeller shaft at one end of the support plate, and is fixed on a rod end ring passing on the outer circle of the propeller piston at the other end; a spring passes through the pitch rod and is located between the guide sleeve assembly and the guide snap ring; a small pitch stop nut is between the piston boss and the rod end ring; and a carbon block assembly is placed in a U-shaped ring groove of the low pitch stop ring. The invention has simple structure, light weight, small volume and high protection reliability.

Description

Technical Field

[0001] The invention relates to a propeller small pitch limiting mechanism in an idle state. Background Art

[0002] The gear pump in the JST-2 speed governor rotates at high speed to provide high-pressure oil for the positive pitch-changing propeller. In order to ensure that the propeller has a small pitch limit function, a small pitch stop mechanism, i.e., a fixed pitch protection mechanism, is required. When the propeller changes from feathering to a certain blade angle α, such as a small pitch angle of about 18°, it stops and cannot continue to change the pitch. In other words, the propeller is stopped at the preset blade angle to prevent the propeller from spinning wildly and affecting flight safety. In the past, propellers used an end face gear meshing mechanism for fixed pitch protection. The end face gear meshing mechanism has a complex structure, which increases the volume and weight of the propeller and can no longer meet the use requirements of some aircraft and other aircraft. Summary of the invention

[0003] The purpose of the present invention is to solve the above problems existing in the prior art and to provide a propeller small pitch limiting mechanism in an idling state which has a simple structure, light weight, small size and high protection reliability.

[0004] To achieve the above purpose, the technical solution of the present invention is: a propeller small pitch limit mechanism in slow-speed state, comprising at least two pitch change rods, a support plate, a guide sleeve assembly, a spring, a guide snap ring, a low pitch stop ring with a U-shaped ring groove on the outer circle, a small pitch stop nut, a piston boss, a rod end ring, a propeller carbon block assembly and a beta valve assembly of a speed governor; the support plate is sleeved on the outside of the propeller shell away from one end of the propeller piston and fixed on the propeller shell, and the through holes Ⅰ of each pitch change rod are evenly opened on the support plate; the guide sleeve assembly is sleeved and fixed in the through hole Ⅰ of the support plate; the guide snap ring is fixed on the outer circle of the other end of the propeller shell; a piston boss is raised on the propeller piston, and a through hole Ⅱ of the pitch change rod is opened on the piston boss; The centers of the through hole II on the guide sleeve assembly, the guide retaining ring and the piston boss are on the same axis; the small-pitch stop nut is fixed on the pitch rod; the pitch rod passes through the through hole II of the guide sleeve assembly, the guide retaining ring and the piston boss, and is fixed on the low-pitch stop ring passing through the outside of the propeller shaft at one end of the support plate, and the other end is fixed on the rod end ring passing through the outer circle of the propeller piston; the spring passes through the pitch rod and is located between the guide sleeve assembly and the guide retaining ring; the small-pitch stop nut is between the piston boss and the rod end ring; the carbon block assembly is placed in the U-shaped ring groove of the low-pitch stop ring, and the left end face of the carbon block assembly is against the wall of the U-shaped ring groove in the initial installation position; the piston rod of the beta valve assembly is connected to the carbon block assembly through a hinged anti-propeller lever.

[0005] Further preferably, the low-distance stop ring has a connecting plate on the outer wall of one end of the support plate, the connecting plate has a thickened protrusion at the fixed position of the pitch change rod, the connecting plate has a threaded hole matching the thread of the end of the pitch change rod at the position of the thickened protrusion, the end of the pitch change rod is threadedly connected to the threaded hole of the connecting plate and is locked and fixed by a locking nut I. This structure is simple and reliable to fix and easy to disassemble.

[0006] Further preferably, the other end of the pitch rod is fixed on the rod end ring that passes through the outer circle of the propeller piston in the structure that: a through hole III is opened at the corresponding position of the rod end ring, the pitch rod passes through the through hole III, and the rod end ring is clamped and fixed by the thin gear nut and the locking nut II that are threadedly fixed on the pitch rod. This structure is simple and reliable to fix, and easy to disassemble.

[0007] When the engine is slow, the high-pressure oil pumped out by the speed governor enters the propeller cavity, and the propeller moves from the straight propeller to the low pitch direction. When the propeller blade angle decreases to an angle of α, the propeller piston drives the piston boss to press against the low pitch stop nut on the pitch change rod, and the propeller continues to change the pitch. The piston drives the low pitch stop nut, the pitch change rod and the low pitch stop ring to move in the low pitch direction. The low pitch stop ring drives the carbon block assembly to move, and the beta valve moves under the action of the movement of the carbon block and the elastic force of the return spring. The boss on the beta valve closes the oil circuit, so that the propeller blade angle is automatically maintained at a certain blade angle. The present invention sets the fixed pitch protection function in the propeller control oil circuit to achieve it, but only sets a structure for sensing the change of the propeller small pitch angle on the beta valve. Once the propeller pitch reaches the small pitch angle, the beta valve moves to block the propeller small pitch oil inlet, so that the propeller is fixed pitch and the protection function is achieved. The present invention has a simple structure, light weight, small size, high protection reliability, and fully meets the requirements of the development of propellers towards light weight. BRIEF DESCRIPTION OF THE DRAWINGS

[0008] Figure 1 It is a schematic diagram of the installation structure of the present invention. DETAILED DESCRIPTION

[0009] The present invention is further described below in conjunction with the accompanying drawings and specific embodiments.

[0010] like Figure 1As shown, this embodiment includes three (or two, four, etc., preferably three) pitch rods 7, a support plate 16, a guide sleeve assembly 17, a spring 20, a guide snap ring 8, a low pitch stop ring 15 with a U-shaped ring groove 21 on the outer circle, a small pitch stop nut 10, a piston boss 9, a rod end ring 13, a carbon block assembly 19 of the propeller 6 and a beta valve assembly 5 of the speed governor 1. The support plate 16 is sleeved on the propeller shell 14 at one end away from the propeller piston 22 and fixed on the propeller shell 14, and the through holes I of each pitch rod 7 are uniformly opened on it. The guide sleeve assembly 17 is sleeved and fixed in the through hole I of the support plate 16. The guide snap ring 8 is fixed on the outer circle of the other end of the propeller shell 14. A piston boss 9 is raised on the propeller piston 22, and a through hole II of the pitch rod 7 is opened on the piston boss 9. The centers of through holes II on the guide sleeve assembly 17, guide snap ring 8 and piston boss 9 are on the same axis. The small pitch stop nut 10 is fixed on the pitch rod 7. The pitch rod 7 passes through the through hole II of the guide sleeve assembly 17, guide snap ring 8 and piston boss 9, and is fixed on the low pitch stop ring 15 passing through the propeller shaft at one end of the support plate 16, and is fixed on the rod end ring 13 passing through the outer circle of the propeller piston 22 at the other end. The spring 20 passes through the pitch rod 7 and is located between the guide sleeve assembly 17 and the guide snap ring 8. The small pitch stop nut 10 is between the piston boss 9 and the rod end ring 13. The carbon block assembly 19 is placed in the U-shaped ring groove 21 of the low pitch stop ring 19, and the left end face of the carbon block assembly is against the wall of the U-shaped ring groove 21 in the initial installation position. The piston rod 23 of the beta valve assembly 5 is connected to the carbon block assembly 19 through the hinged anti-propeller lever 3. 4 is the reset spring in the beta valve assembly 5. Preferably, the low-pitch stop ring 15 has a connecting plate 24 on the outer wall of one end of the support plate 16, and the connecting plate 24 has a thickened protrusion at the fixed position of the pitch rod 7. The connecting plate 24 has a threaded hole matching the thread of the end of the pitch rod 7 at the position with the thickened protrusion, and the end of the pitch rod 7 is threadedly connected in the threaded hole of the connecting plate 24 and locked and fixed by the locking nut I 18. Preferably, the structure in which the other end of the pitch rod 7 is fixed on the rod end ring 13 passing through the outer circle of the propeller piston 22 is: the rod end ring 13 has a through hole III at the corresponding position, the pitch rod 7 passes through the through hole III, and the rod end ring 13 is clamped and fixed by the gear hexagonal thin nut 1 and the locking nut II 12 threadedly fixed on the pitch rod 7. 2 is a power push-pull rod.

[0011] Of course, the present invention has many other embodiments. Without violating the spirit and essence of the present invention, technicians familiar with the field can make corresponding changes and deformations based on the present invention, but these corresponding changes and deformations should be regarded as improvements of equivalent technologies and belong to the protection scope of the claims of the present invention.

Claims

1. A propeller short pitch limit mechanism in slow-speed state, Features: It includes at least two pitch rods, a support plate, a guide sleeve assembly, a spring, a guide snap ring, a low-pitch stop ring with a U-shaped ring groove on the outer circle, a small-pitch stop nut, a piston boss, a rod end ring, a propeller carbon block assembly and a beta valve assembly of a speed regulator; the support plate is sleeved on the outside of the propeller shell away from one end of the propeller piston and fixed on the shell, and through holes Ⅰ for each pitch rod are evenly opened on it; the guide sleeve assembly is sleeved and fixed in the through hole Ⅰ of the support plate; the guide snap ring is fixed on the outer circle of the other end of the propeller shell; a piston boss is raised on the propeller piston, and a through hole Ⅱ for the pitch rod is opened on the piston boss; the through holes on the guide sleeve assembly, the guide snap ring and the piston boss The centers of Ⅱ are on the same axis; the small pitch stop nut is fixed on the pitch rod; the pitch rod passes through the through hole Ⅱ of the guide sleeve assembly, the guide retaining ring and the piston boss, and is fixed on the low pitch stop ring passing through the propeller shaft at one end of the support plate, and the other end is fixed on the rod end ring passing through the outer circle of the propeller piston; the spring passes through the pitch rod and is located between the guide sleeve assembly and the guide retaining ring; the small pitch stop nut is between the piston boss and the rod end ring; the carbon block assembly is placed in the U-shaped ring groove of the low pitch stop ring, and the left end face of the carbon block assembly is against the wall of the U-shaped ring groove in the initial installation position; the piston rod of the beta valve assembly is connected to the carbon block assembly through a hinged anti-propeller lever; The low-pitch stop ring has a connecting plate on the outer wall of one end of the support plate, the connecting plate has a thickened protrusion at the fixed position of the pitch change rod, and the connecting plate has a threaded hole matching the thread of the end of the pitch change rod at the position of the thickened protrusion, the end of the pitch change rod is threadedly connected to the threaded hole of the connecting plate and is locked and fixed by a locking nut I; The other end of the pitch rod is fixed on the rod end ring which is passed through the outer circle of the propeller piston. The structure is as follows: a through hole III is opened at the corresponding position of the rod end ring, the pitch rod is passed through the through hole III, and the rod end ring is clamped and fixed by a thin gear nut and a locking nut II which are threadedly fixed on the pitch rod.

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