Short-handle aero-engine crankshaft

Abstract

A short-handle aero-engine crankshaft comprises a left crank and a right crank, the left crank or / and the right crank is composed of a main shaft part and a crank disc part, and the crank disc part is provided with an eccentric shaft used for installing a connecting rod; a cylindrical surface for mounting a rolling bearing is arranged at the outer edge part of the curved disc part; and the cylindrical surface and the main shaft part are coaxially arranged. The rolling bearing is mounted on the cylindrical surface of the bent disc part, so that the total length of the crankshaft and the casing can be effectively shortened, the manufacturing cost and the manufacturing difficulty of the crankshaft and the casing are reduced, and the size and the weight of an aero-engine are reduced. Particularly for the crankshaft, the interference of the crankshaft can be reduced due to the shortening of the length, and the machining precision of the crankshaft can be improved. Due to the fact that the installation size of the rolling bearing is increased, a large-diameter bearing with a large number of rolling bodies can be selected to prolong the service life of the rolling bearing.

Description

Technical Field

[0001] The present invention relates to the technical field of aero-engines, in particular to a short-handled aero-engine crankshaft. Background Art

[0002] A piston aircraft engine primarily consists of a crankshaft, connecting rod, piston, cylinder, valve train, and casing. The cylinders are often arranged horizontally. Currently, common horizontally opposed aircraft engines include opposed four-cylinder, opposed six-cylinder, and opposed eight-cylinder engines.

[0003] Refer to the attached Figure 1 and attached Figure 2 , attached Figure 1 The diagram shows the structure of the crankshaft and casing of the existing opposed four-cylinder aircraft engine. Figure 2 What is shown is the structural diagram of the existing left crank. Figure 1 and attached Figure 2 As can be seen, the crankshaft comprises a left crank 1 and a right crank 2. The left crank 1 is connected to the propeller, while the right crank 2 is connected to the magneto 6. The crankshaft is relatively long overall. Each crank is primarily composed of a main shaft 21 and a crank throw 11. The crank throw 11 includes an eccentric shaft for mounting a connecting rod. A pair of bearing assemblies 7 are positioned between the main shafts 11 of the left and right cranks and the casing 5. These bearing assemblies support the crankshaft's rotation during operation.

[0004] Due to the small diameter of the main shaft portion 21, smaller bearings are required. However, smaller bearings contain fewer rolling elements, and each rolling element carries a greater load, which can easily lead to premature wear of the rolling elements. To increase the bearing's service life, each bearing assembly typically consists of two ball bearings and a spacer ring, resulting in a larger overall width. This results in a longer combined length for the crankshaft and casing. This increased combined length increases both their manufacturing costs and the manufacturing difficulty. The increased crankshaft length, in particular, increases the crankshaft's tampering, making it difficult to maintain machining accuracy. Summary of the Invention

[0005] In order to overcome the deficiencies in the background art, the present invention discloses a short-shank aircraft engine crankshaft, the purpose of which is:

[0006] 1. Reduce the manufacturing cost and difficulty of the crankshaft and casing;

[0007] 2. Extend the service life of bearings.

[0008] Specifically, the present invention adopts the following technical solutions:

[0009] A short-handle aircraft engine crankshaft includes a left crank and a right crank. The left crank and / or the right crank are composed of a main shaft portion and a crank plate portion. The crank plate portion has an eccentric shaft for mounting a connecting rod. A cylindrical surface for mounting a rolling bearing is provided on the outer edge of the crank plate portion. The cylindrical surface is coaxially arranged with the main shaft portion.

[0010] After implementing the above technical solution, compared with the background technology, the beneficial effects produced are:

[0011] 1. Installing the rolling bearing on the cylindrical surface of the crankshaft can effectively shorten the total length of the crankshaft and casing, thereby reducing the manufacturing cost and difficulty of the crankshaft and casing;

[0012] 2. As the installation size of rolling bearings is increased, large-diameter bearings with a large number of rolling elements can be selected to increase the service life of rolling bearings.

[0013] 3. In application fields such as drones, there are more stringent requirements on the size and weight of aircraft engines. Shortening the overall length of the crankshaft and casing can effectively reduce the volume and weight of aircraft engines.

[0014] To further improve the technical solution, a shoulder is provided on one side of the cylindrical surface, and the shoulder is used to limit the axial position of the rolling bearing.

[0015] After the above technical solution is implemented, the beneficial effect produced is that the shaft shoulder can limit the axial position of the rolling bearing and prevent the rolling bearing from axial movement.

[0016] To further improve the technical solution, the shaft shoulder is arranged on a side of the cylindrical surface close to the eccentric shaft.

[0017] After the above technical solution is implemented, the beneficial effect is that the shaft shoulder is arranged on the side of the cylindrical surface close to the eccentric shaft, which facilitates the installation of the rolling bearing on the curved plate portion.

[0018] To further improve the technical solution, a detachable pressure ring is provided on the other side of the cylindrical surface, and the pressure ring is used to press the inner ring of the rolling bearing axially against the shaft shoulder.

[0019] After the above technical solution is implemented, the beneficial effect produced is that the pressure ring can press the inner ring of the rolling bearing axially against the shaft shoulder, thereby achieving axial fixation of the inner ring of the bearing.

[0020] To further improve the technical solution, a threaded connection structure is provided between the pressure ring and the curved disc, and the pressure ring and the curved disc are detachably connected via the threaded connection structure. Alternatively, a stopper positioning structure is provided between the pressure ring and the curved disc, and the pressure ring and the curved disc are detachably connected via screws and the stopper positioning structure.

[0021] After implementing the above technical solution, the beneficial effect is that both of the two detachable modes facilitate the installation of the rolling bearing and the axial fixation of the bearing inner ring.

[0022] To further improve the technical solution, the short-handled aircraft engine crankshaft is installed in the casing, and an oil seal is provided between the pressure ring and the casing.

[0023] After implementing the above technical solution, the beneficial effects are: the oil seal can realize dynamic sealing between the crankshaft and the casing, and the oil seal is arranged between the pressure ring and the casing, which facilitates the installation and removal of the oil seal. BRIEF DESCRIPTION OF THE DRAWINGS

[0024] Attachment Figure 1 Shown is a schematic structural diagram of a crankshaft and casing of a conventional opposed four-cylinder aircraft engine.

[0025] Attachment Figure 2 What is shown is the structural schematic diagram of the existing left crank.

[0026] Attachment Figure 3 Shown is a schematic structural diagram of the crankshaft and casing in Example 1.

[0027] Attachment Figure 4 Shown is the attached Figure 3 Schematic diagram of the structure of the middle right crank.

[0028] Attachment Figure 5 Shown is a schematic structural diagram of the crankshaft and casing in Example 2.

[0029] Attachment Figure 6 Shown is the attached Figure 5 Schematic diagram of the local structure at P in the figure.

[0030] Attachment Figure 7 The figure shows the schematic diagram of the screw connection structure between the pressure ring and the curved disk part in Example 2.

[0031] Attachment Figure 8 Shown is a schematic structural diagram of the crankshaft and casing in Example 3.

[0032] In the accompanying drawings: 1. Left crank; 11. Crank part; 2. Right crank; 21. Main shaft part; 22. Crank plate part; 221. Cylindrical surface; 222. Eccentric shaft; 223. Shoulder; 23. Pressure ring; 24. Screw; 3. Rolling bearing; 4. Oil seal; 5. Casing; 6. Magneto; 7. Bearing assembly. DETAILED DESCRIPTION

[0033] The preferred embodiments of the present invention are described below with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are only used to explain the technical principles of the present invention and are not intended to limit the scope of protection of the present invention. It should be noted that in the description of the present invention, the terms "front", "rear", "up", "down", "left", "right", "vertical", "horizontal", "inside", "outside" and the like indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is only for the convenience of description and does not indicate or imply that the device or element must have a specific orientation, be constructed and operated in a specific orientation. Therefore, it should not be understood as a limitation of the present invention. It should also be noted that in the description of the present invention, unless otherwise clearly specified and limited, the terms "installed", "connected" and "connected" should be understood in a broad sense. For example, it can be a fixed connection, a detachable connection, or an integral connection; it can be a mechanical connection or an electrical connection; it can be a direct connection, an indirect connection through an intermediate medium, or a communication between two components. For those skilled in the art, the specific meanings of the above terms in the present invention can be understood according to the specific circumstances.

[0034] Example 1:

[0035] Refer to the attached Figure 3 A short-handle aircraft engine crankshaft includes a left crank 1, a right crank 2, and a plurality of crank throws connected between the left crank 1 and the right crank 2. The crankshaft is mounted in a casing 5, with the left crank 1 extending outward from the casing 5 for connection to a propeller, and the right crank 2 extending outward from the casing 5 for connection to a magneto 6, a starting gear, and other components.

[0036] Refer to the attached Figure 4 In this embodiment, the right crank 2 consists of a main shaft portion 21 and a crank plate portion 22. The crank plate portion 22 has an eccentric shaft 222 for mounting a connecting rod. A cylindrical surface 221 is provided on the outer edge of the crank plate portion 22. The diameter of the cylindrical surface 221 is several times that of the main shaft portion 21. The cylindrical surface 221 is coaxial with the main shaft portion 21.

[0037] Refer again to the attached Figure 3 , a large diameter rolling bearing 3 is installed on the cylindrical surface 221. Figure 1 Because the bearing assembly is no longer mounted on the main shaft portion 21, the length of the main shaft portion 21 can be significantly shortened, to only 30-45% of its original length. This effectively reduces the overall length of the crankshaft and casing 5, significantly lowering the manufacturing cost and difficulty of the crankshaft and casing 5, and reducing the size and weight of the aircraft engine. Specifically for the crankshaft, the shortened length reduces its tamper resistance, which helps improve its machining accuracy.

[0038] In addition, since a large-diameter rolling bearing 3 is required, the number of rolling elements in the bearing is multiplied, the load borne by a single rolling element is multiplied, and the service life of the rolling bearing 3 is significantly improved.

[0039] In order to achieve dynamic sealing between the crankshaft and the casing 5 , an oil seal 4 is provided between the cylindrical surface 221 and the casing 5 .

[0040] Example 2:

[0041] The rolling bearing 3 in embodiment 1 has no axial limiting structure, and the rolling bearing 3 may move axially during operation.

[0042] Refer to the attached Figure 5 In order to eliminate the movement, a shoulder 223 is provided on the side of the cylindrical surface 221 close to the eccentric shaft 222, and a detachable pressure ring 23 is provided on the other side of the cylindrical surface 221. The inner ring of the rolling bearing 3 is pressed axially against the shoulder 223 through the screw 24 and the pressure ring 23.

[0043] Refer to the attached Figure 6 In this embodiment, a stopper positioning structure is provided between the pressure ring 23 and the curved disc portion 22. The pressure ring 23 and the curved disc portion 22 are detachably connected via screws 24 and the stopper positioning structure. The stopper positioning structure ensures coaxiality between the pressure ring 23 and the curved disc portion 22. The detachable connection between the pressure ring 23 and the curved disc portion 22 via screws 24 facilitates the installation of the rolling bearing 3 on the curved disc portion 22 and provides axial fixation of the bearing inner ring.

[0044] To achieve a dynamic seal between the crankshaft and the casing 5, an oil seal 4 is provided between the pressure ring 23 and the casing 5. The oil seal in Example 1 is difficult to remove for maintenance and replacement. In this embodiment, the oil seal 4 can be removed by removing the pressure ring 23, facilitating maintenance and replacement of the oil seal.

[0045] In addition, a threaded connection structure may be provided between the pressure ring 23 and the curved disk portion 22 , so that the pressure ring 23 and the curved disk portion 22 can be detachably connected via the threaded connection structure.

[0046] Refer to the attached Figure 7 The outer end of the curved plate portion 22 is provided with an external thread, and the pressure ring 23 is provided with an internal thread. The pressure ring 23 is connected to the curved plate portion 22 by a thread. When the pressure ring 23 is tightened, the inner ring of the rolling bearing 3 is pressed axially against the shaft shoulder 223.

[0047] Example 3:

[0048] Refer to the attached Figure 8This embodiment differs from Example 1 in that the left crank 1 also consists of a main shaft portion 21 and a crank plate portion 22. The crank plate portion 22 has an eccentric shaft 222 for mounting a connecting rod. A cylindrical surface 221 is provided on the outer edge of the crank plate portion 22, coaxially arranged with the main shaft portion 21. A large-diameter rolling bearing 3 is mounted on the cylindrical surface 221. Based on the same principle, since the bearing assembly is no longer mounted on the main shaft portion 21, the length of the left crank 1 can be significantly shortened, thereby further reducing the overall length of the crankshaft.

[0049] Compare with Figure 3 It is known that Figure 8 The crankshaft and casing 5 in the casing are shortened, and the overall length is further shortened. Obviously, the manufacturing cost and the manufacturing difficulty of the crankshaft and casing 5 can be further reduced like this.

[0050] Parts not described in detail are prior art. Although embodiments of the present invention have been shown and described, it will be understood by those skilled in the art that various changes, modifications, substitutions, and variations may be made to these embodiments without departing from the principles and spirit of the present invention, and the scope of protection of the present invention is defined by the appended claims and their equivalents.

Claims

1. A short-handled aircraft engine crankshaft, comprising a left crank and a right crank, Its characteristics are: The left crank or / and the right crank consists of a main shaft part and a crank plate part, the crank plate part has an eccentric shaft for installing a connecting rod; a cylindrical surface for installing a rolling bearing is provided on the outer edge of the crank plate part, and the cylindrical surface is coaxially arranged with the main shaft part.

2. A short-handled aircraft engine crankshaft as claimed in claim 1, Its characteristics are: A shoulder is provided on one side of the cylindrical surface, and the shoulder is used to limit the axial position of the rolling bearing.

3. A short-handled aircraft engine crankshaft as claimed in claim 2, Its characteristics are: The shaft shoulder is arranged on one side of the cylindrical surface close to the eccentric shaft.

4. A short-shank aircraft engine crankshaft as claimed in claim 2 or 3, Its characteristics are: A detachable pressing ring is arranged on the other side of the cylindrical surface, and the pressing ring is used to press the inner ring of the rolling bearing axially against the shaft shoulder.

5. A short-shank aircraft engine crankshaft as claimed in claim 4, Its characteristics are: A threaded connection structure is provided between the pressure ring and the curved disk portion, and the pressure ring and the curved disk portion are detachably connected via the threaded connection structure.

6. A short-shank aircraft engine crankshaft as claimed in claim 4, Its characteristics are: A stopper positioning structure is arranged between the pressure ring and the curved disk portion, and the pressure ring and the curved disk portion are detachably connected by screws and the stopper positioning structure.

7. A short-shank aircraft engine crankshaft as claimed in claim 5 or 6, Its characteristics are: The short-handled aircraft engine crankshaft is installed in a casing, and an oil seal is arranged between the pressure ring and the casing.

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