Horizontally opposed aero-engine casing

Abstract

A bearing hole used for installing a crankshaft is formed in the horizontally-opposed aero-engine case, the crankshaft is formed by connecting a left crank, two middle cranks and a right crank, two ball bearings are installed on the left crank, a needle bearing is installed on the right crank, the two middle cranks are connected together through a connecting sleeve, and the two ball bearings are connected with the needle bearing through the connecting sleeve. Two needle bearings and a spacer bush are installed on the connecting sleeve, outer ring grooves are formed in the needle bearings and the spacer bush respectively, and oil inlet holes are formed in the outer ring grooves; an oil channel for supplying oil to a bearing hole is formed in the casing, a plurality of positioning holes are formed in the bearing hole, positioning pins are installed in the positioning holes, and the head ends of the positioning pins abut against the interior of the outer ring groove and are used for axially limiting the needle bearing and the spacer bush. According to the casing, the positioning problem and the lubricating problem of the crankshaft bearing are solved, the working condition of the bearing can be effectively improved, the service life of the bearing is prolonged, and the risk that the crankshaft is scrapped due to damage of the bearing is greatly reduced.

Description

Technical Field

[0001] The utility model relates to the technical field of aviation engines, in particular to a horizontally opposed aviation engine casing. Background Art

[0002] A piston aircraft engine primarily consists of a crankshaft, connecting rod, piston, cylinder, valve train, and casing. Currently, cylinders are often arranged horizontally, with the most common horizontally opposed aircraft engine being the opposed four-cylinder version.

[0003] Refer to the attached Figure 1 The casing 1 of an opposed four-cylinder aircraft engine consists of an upper casing and a lower casing. During assembly, the crankshaft is installed in the bearing hole 11 of the casing, and the cylinders are installed on both sides of the casing 1. Existing multi-crank crankshafts often adopt an integrated forging structure, which is difficult to process and has high manufacturing costs. In particular, the middle crank can only be supported by a split bearing. The bearing is a sliding bearing and is only suitable for medium and low-speed engines (3000-6000rpm). However, aircraft engines are high-speed engines (6000-10000rpm). In addition to the easy wear of the bearing during operation, the abrasive particles dropped from the bearing will also cause rapid wear of the journal.

[0004] Refer to the attached Figure 2 To replace the split bearings, the crankshaft 2 of the opposed four-cylinder aircraft engine adopts a split-combination structure. Two ball bearings 24 are installed on the left crank 21, and a needle bearing 26 is installed on the right crank 23. The middle crank 22 is connected by a connecting sleeve 25, and two needle bearings 26 and a spacer sleeve 27 are installed on the connecting sleeve 25. The split-combination structure of the crankshaft realizes the installation of rolling bearings on the crankshaft, solving the problem of easy wear of the bearings. However, it also brings a new problem: the two needle bearings on the connecting sleeve are difficult to remove and replace. Once these two needle bearings have problems, the entire crankshaft is at risk of being scrapped. Therefore, it is necessary to make corresponding improvements to the casing to improve the working conditions of the needle bearings and increase the service life of the needle bearings. Utility Model Content

[0005] In order to overcome the shortcomings of the background technology, the utility model discloses a horizontally opposed aircraft engine casing, which adopts the following technical solutions:

[0006] A horizontally opposed aircraft engine casing is provided with a bearing hole for mounting a crankshaft, wherein the crankshaft is connected by a left crank, two intermediate cranks and a right crank, two ball bearings are mounted on the left crank, a needle bearing is mounted on the right crank, the two intermediate cranks are connected together by a connecting sleeve, two needle bearings and a spacer sleeve are mounted on the connecting sleeve, outer ring grooves are respectively provided on the needle bearings and the spacer sleeve, and an oil inlet hole is provided in the outer ring groove; an oil channel for supplying oil to the bearing hole is provided in the casing, a plurality of positioning holes are provided in the bearing hole, and a positioning pin is mounted in the positioning hole, the head end of the positioning pin is pressed against the outer ring groove, and is used to axially limit the needle bearing and the spacer sleeve.

[0007] To further improve the technical solution, the outer diameter of the ball bearing is the same as the outer diameter of the needle bearing and the spacer sleeve.

[0008] To further improve the technical solution, two inner ring grooves are provided in the bearing hole, and retaining rings are installed in the inner ring grooves. The retaining rings are used to axially position the outer ring of the ball bearing.

[0009] To further improve the technical solution, a plurality of oil grooves are provided on the inner ring surface of the spacer.

[0010] To further improve the technical solution, oil seal positioning ring grooves are provided at both ends of the bearing hole.

[0011] After implementing the above technical solution, compared with the background technology, the beneficial effects produced by the present invention are:

[0012] The casing of the utility model solves the positioning and lubrication problems of the crankshaft bearings, can effectively improve the working conditions of the bearings, increase the service life of the bearings, and greatly reduce the risk of the crankshaft being scrapped due to bearing damage. BRIEF DESCRIPTION OF THE DRAWINGS

[0013] Attachment Figure 1 Shown is a schematic diagram of the three-dimensional structure of an opposed four-cylinder aircraft engine casing.

[0014] Attachment Figure 2 Shown is a schematic structural diagram of an opposed four-cylinder aircraft engine crankshaft.

[0015] Attachment Figure 3 What is shown is the schematic cross-sectional structure diagram of the casing.

[0016] Attachment Figure 4 Shown is a schematic structural diagram of a needle roller bearing.

[0017] Attachment Figure 5 Shown is a schematic diagram of the installation structure of the crankshaft in the casing.

[0018] Attachment Figure 6 Shown is the attached Figure 5 A partial enlarged view of point A in the middle.

[0019] In the accompanying drawings: 1. Casing; 11. Bearing hole; 12. Locating pin; 13. Retaining ring; 14. Oil seal locating ring groove; 15. Oil channel; 2. Crankshaft; 21. Left crank; 22. Intermediate crank; 23. Right crank; 24. Ball bearing; 25. Connecting sleeve; 26. Needle roller bearing; 261. Outer ring groove; 262. Oil inlet hole; 27. Spacer. DETAILED DESCRIPTION

[0020] The following describes preferred embodiments of the present invention with reference to the accompanying drawings. Those skilled in the art should understand that these embodiments are merely intended to illustrate 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, terms such as "front," "rear," "up," "down," "left," "right," "vertical," "horizontal," "inside," and "outside" indicating directions or positional relationships are based on the directions or positional relationships shown in the accompanying drawings. This is merely for ease of description and does not indicate or imply that the device or component must have a specific orientation, be constructed, or operate in a specific orientation. Therefore, they should not be construed as limitations on the present invention. It should also be noted that, in the description of the present invention, unless otherwise expressly specified or limited, the terms "mounted," "connected," and "connected" should be understood broadly. For example, they can mean fixed, detachable, or integral; mechanical or electrical; direct, indirect through an intermediary, or internal communication between two components. Those skilled in the art will understand the specific meanings of the above terms in the present invention based on the specific circumstances.

[0021] Refer to the attached Figure 3 , attached Figure 3 The figure shows a cross-sectional view of a horizontally opposed four-cylinder aircraft engine casing. Figure 3 As can be seen, the casing 1 includes a bearing hole 11 for mounting the crankshaft 2. Two cavities within the casing 1 divide the bearing hole 11 into three sections. The left section of the bearing hole 11 corresponds to the two ball bearings 24 on the left crank 21, the right section of the bearing hole 11 corresponds to the single needle bearing 26 on the right crank 23, and the center section of the bearing hole 11 corresponds to the two needle bearings 26 on the connecting sleeve 25. Because the outer diameter of the ball bearings 24 is the same as that of the needle bearings 26 and the spacer sleeve 27, all three sections of the bearing hole 11 can be bored out in a single cut, reducing the machining difficulty of the bearing hole 11.

[0022] Refer to the attached Figure 3 and attached Figure 4. The main factors affecting the service life of the needle bearing 26 are lubrication and positioning. In order to solve the axial limitation and lubrication problems of the needle bearing 26, an outer ring groove 261 is provided on the needle bearing 26 and the spacer sleeve 27 respectively, and an oil inlet hole 262 is provided in the outer ring groove 261, wherein a plurality of oil grooves are provided on the inner ring surface of the spacer sleeve 27. An oil channel 15 for supplying oil to the bearing hole 11 is provided in the casing 1, and four positioning holes are provided in the bearing hole 11, and positioning pins 12 are installed in the positioning holes. The head ends of the three larger positioning pins 12 are pressed against the outer ring groove 261 of the needle bearing 26, respectively limiting the axial position of the three needle bearings 26. The head end of a smaller positioning pin 12 is pressed against the outer ring groove 261 of the spacer sleeve 27, limiting the axial position of the spacer sleeve 27.

[0023] In addition, two inner ring grooves are provided in the left bearing hole 11, and retaining rings 13 are installed in the inner ring grooves. The retaining rings 13 are used to axially locate the outer rings of the two ball bearings 24 on the left crank 21. An oil seal positioning ring groove 14 is also provided at the outer ends of the left and right bearing holes 11. The oil seal positioning ring groove 14 is used to axially locate the oil seal.

[0024] Refer to the attached Figure 5 and attached Figure 6 Since the locating pin 12 axially locates the needle roller bearing 26 and the spacer sleeve 27, and the retaining ring 13 axially locates the ball bearing 24 and bears the axial force from the crankshaft 2, it can prevent the needle roller bearing 26, the ball bearing 24 and the spacer sleeve 27 from axially moving during operation, thereby preventing the crankshaft 2 from axially moving.

[0025] During operation, one channel of lubricating oil flows from the oil passage 15 into the left section bearing hole 11, lubricating the two ball bearings 24, and then flows into the cavity of the casing 1. Another channel of lubricating oil flows from the oil passage 15 into the middle section bearing hole 11 and the right section bearing hole 11, lubricating the three needle roller bearings 26 through the outer ring groove 261 and the oil inlet hole 262, and then flows into the cavity of the casing 1.

[0026] From the above, it can be seen that this casing solves the positioning and lubrication problems of the crankshaft bearings, can effectively improve the working conditions of the crankshaft bearings, increase the service life of the crankshaft bearings, and greatly reduce the risk of the crankshaft being scrapped due to bearing damage.

[0027] Parts not described in detail are prior art. Although the 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 horizontally opposed aircraft engine casing having a bearing hole therein for mounting a crankshaft, wherein the crankshaft is composed of a left crank, two intermediate cranks, and a right crank connected together, the left crank being mounted with two ball bearings, the right crank being mounted with a needle bearing, the two intermediate cranks being connected together by a connecting sleeve, the connecting sleeve being mounted with two needle bearings and a spacer sleeve, and characterized by: An outer ring groove is provided on the needle roller bearing and the spacer sleeve respectively, and an oil inlet hole is provided in the outer ring groove; an oil channel for supplying oil to the bearing hole is provided in the casing, and a plurality of positioning holes are provided in the bearing hole, and a positioning pin is installed in the positioning hole. The head end of the positioning pin is pressed in the outer ring groove for axially limiting the needle roller bearing and the spacer sleeve.

2. The horizontally opposed aircraft engine casing according to claim 1, wherein: The outer diameter of the ball bearing is the same as that of the needle roller bearing and the spacer.

3. The horizontally opposed aircraft engine casing according to claim 1, wherein: Two inner ring grooves are provided in the bearing hole, and retaining rings are installed in the inner ring grooves. The retaining rings are used to axially position the outer ring of the ball bearing.

4. The horizontally opposed aircraft engine casing according to claim 1, wherein: A plurality of oil grooves are provided on the inner ring surface of the spacer.

5. The horizontally opposed aircraft engine casing according to claim 1, wherein: Oil seal positioning ring grooves are also provided at both ends of the bearing hole.

Images