A special crankshaft structure for a drone

Abstract

The utility model provides a kind of special crankshaft structure of unmanned plane, including left crank, intermediate crank, right crank, connecting rod, the left crank is connected with intermediate crank, the intermediate crank is connected with right crank by crank pin, bearing is connected on the crank pin, fixed hole is set up on the connecting rod, the bearing is fixed in fixed hole, connecting rod includes fixed end, connecting section and mounting end, the both ends of connecting section are connected with fixed end, mounting end respectively, the fixed hole is set up on fixed end, oiling groove that is communicated with fixed hole is set up on the outer wall of fixed end, oil inlet hole that is corresponding with oiling groove is set up on the outer ring of bearing, reach the purpose that promote lubrication effect, reduce abrasion.

Description

Technical Field

[0001] This utility model relates to crankshafts, and more particularly, to a crankshaft structure specifically for unmanned aerial vehicles (UAVs). Background Technology

[0002] As a core component of engine power transmission, the crankshaft of a drone needs to withstand high speeds and complex alternating loads. The reliability of its structure is directly related to the flight performance of the drone.

[0003] Currently, Chinese patent authorization announcement number CN217055930U discloses a crankshaft for unmanned aerial vehicles. This technical solution sets a first rotating sleeve between the crankshaft arm and the journal, and uses an internal telescopic rod to drive the double-sided arc-shaped top block to rotate, thereby pushing the insertion rod to engage with the rotating sleeve, realizing the rapid fixing and disassembly of the crankshaft arm and the journal.

[0004] However, since drone engines typically operate at extremely high speeds, there is intense relative motion between the crankshaft journals, rotating sleeves, and connecting rod mating surfaces. The aforementioned patent lacks effective lubrication channels or oil reservoirs, resulting in the mating surfaces being in a state of dry friction or boundary lubrication for extended periods. This lack of lubrication not only generates significant frictional heat but also accelerates wear and fatigue spalling on the journal and rotating sleeve surfaces. Utility Model Content

[0005] In view of this, the purpose of this utility model is to provide a crankshaft structure specifically for drones, which improves lubrication and avoids dry friction and premature wear caused by the inability to add lubricating oil.

[0006] To solve the above-mentioned technical problems, the technical solution of this utility model is: a crankshaft structure for UAVs, including a left crank, a middle crank, a right crank, and a connecting rod. The left crank is connected to the middle crank, and the middle crank is connected to the right crank via a crank pin. A bearing is connected to the crank pin. A fixing hole is provided on the connecting rod, and the bearing is fixed in the fixing hole. The connecting rod includes a fixed end, a connecting section, and a mounting end. The two ends of the connecting section are respectively connected to the fixed end and the mounting end. The fixing hole is provided on the fixed end. An oil filling groove communicating with the fixing hole is provided on the outer wall of the fixed end, and an oil inlet hole corresponding to the oil filling groove is provided on the outer ring of the bearing.

[0007] To achieve the above technical solution, while the UAV is in a stationary maintenance state, the operator uses a lubrication tool to fill the lubrication groove on the outer wall of the connecting rod fixing end. Under the influence of gravity or injection pressure, the lubricating oil flows along the groove and directly seeps into the bearing's interior and the clearance between the bearing and crankpin through the corresponding oil inlet hole on the bearing's outer ring. This allows the operator to conveniently lubricate and maintain the crankshaft before takeoff, ensuring that lubricating medium is present between the mating surfaces at the moment of engine start-up and during subsequent operation, thus avoiding dry friction and premature wear caused by the inability to add lubricating oil.

[0008] As a preferred embodiment of this utility model, the opening area of ​​the oil injection groove on the outer wall of the fixed end is larger than its opening area on the inner wall of the fixed hole.

[0009] To achieve the above technical solution, the structural feature that the opening area of ​​the oil injection groove on the outer wall of the fixed end is larger than its opening area on the inner wall of the fixed hole creates a funnel-shaped oil injection window on the outer wall of the connecting rod. During static oil injection, the larger external opening area reduces the precision requirements for the positioning of the oil injection tool, effectively catches the lubricating oil dripping or spraying from the tool, and guides the lubricating oil smoothly into the smaller oil inlet hole, improving the convenience of manual maintenance and the efficiency of oil injection.

[0010] As a preferred embodiment of this utility model, a connecting groove is provided on the side wall of the fixed end, one end of the connecting groove is connected to the opening of the fixed hole, and the other end of the connecting groove is connected to the end face of the fixed end.

[0011] To achieve the above technical solution, during the oil injection process, once the lubricating oil fills the internal gap of the fixed hole, the connecting groove acts as an exhaust and flow guide channel, avoiding air resistance and facilitating the smooth introduction of lubricating oil. Overflowing lubricating oil is forcibly guided by the connecting groove to the side wall surface of the fixed end. During the operation of the UAV, the connecting rod is subjected to axial force and rubs against the cranks or washers on both sides. At this time, the lubricating oil remaining in the connecting groove can, with the assistance of centrifugal force, quickly spread to the thrust contact surface between the side wall of the fixed end and the crank structure, forming a protective oil film on the side. This extends the lubrication range from the interior of a single shaft hole to the side of the connecting rod, effectively solving the problem of burning and wear on the big end side of the connecting rod due to lack of lubrication.

[0012] As a preferred embodiment of this utility model, an annular oil storage groove is provided on the inner wall of the fixing hole, and the annular oil storage groove is connected to the oil injection groove.

[0013] To achieve the above technical solution, manually injected lubricating oil enters through the oil inlet, with a portion of it flowing into the annular oil reservoir. This annular oil reservoir acts as a basic oil tank inside the connecting rod, significantly increasing the effective oil storage volume after a single static oil injection. During high-speed engine operation, the annular oil reservoir, with its concave structure, reduces the rapid ejection of lubricating oil from the bearing end face due to the enormous centrifugal force generated by crankshaft rotation, thus maintaining a relatively durable oil ring inside the fixed hole and ensuring a continuous supply of oil to the needle roller bearing.

[0014] As a preferred embodiment of this utility model, an oil storage groove is formed on the inner wall of the annular oil storage tank.

[0015] To achieve the above technical solution, oil storage grooves are further machined into the inner wall of the annular oil reservoir. During the oil filling stage, the lubricating oil will preferentially fill into the deepest oil storage groove by gravity or pressure. During operation, even if the shallow lubricating oil is thrown out, the deep oil storage grooves, with their larger depth-to-width ratio, can greatly enhance the binding ability of the lubricating oil by utilizing the adhesion and surface tension of the liquid.

[0016] As a preferred embodiment of this utility model, an oil-absorbing felt is provided on the inner wall of the oil storage groove.

[0017] To achieve the above technical solution, the oil-absorbing felt placed in the oil storage groove quickly absorbs lubricating oil to a saturated state during oil injection, transforming the flowing liquid oil into a semi-solid oil film mainly locked by capillary force. This prevents lubricating oil from being lost due to gravity during storage when the drone is not in use. When the drone starts operating, the oil-absorbing felt is subjected to centrifugal compression and frictional heat, causing lubricating oil to slowly seep out through the fiber pores to the surface of the bearing needle rollers. This transforms a one-time oil injection operation into a long-lasting, continuous lubrication process, significantly extending the maintenance-free flight time of the drone.

[0018] As a preferred embodiment of this utility model, the crank pin includes a first fixed section, a support section, and a second fixed section. The two ends of the support section are respectively connected to the first fixed section and the second fixed section. The first fixed section is connected to the middle crank, and the second fixed section is connected to the right crank. The outer circumference of the support section is provided with a spiral oil guide pattern.

[0019] To achieve the above technical solution, after oil injection, the lubricating oil mainly accumulates in localized areas near the oil injection hole and oil reservoir. When the drone starts and the crank pin begins to rotate at high speed relative to the connecting rod, the spiral oil guiding grooves on the outer circumference of the support section rotate accordingly. These spiral oil guiding grooves utilize the spiral conveying principle to actively push the locally accumulated lubricating oil axially, forcing it to spread throughout the entire length of the support section. This avoids localized dry wear caused by uneven oil distribution and improves the utilization efficiency of the lubricating oil.

[0020] As a preferred embodiment of this utility model, the cross-section of the spiral oil guide pattern is all arc-shaped.

[0021] By implementing the above technical solution, the arc-shaped groove bottom can guide the lubricating oil to flow smoothly without any dead corners or residues during oil filling and subsequent operations. Furthermore, when the crankshaft bearing is subjected to severe impact loads generated by the engine's power stroke, the arc-shaped cross-section eliminates stress concentration sources at sharp corners, ensuring that the crankpin's bending and torsional fatigue strength remains unaffected even after the oil-guiding grooves are etched on its surface. This ensures lubrication while maintaining the integrity and safety of the crankshaft structure under extreme operating conditions. Attached Figure Description

[0022] Figure 1 This is a schematic diagram of the structure of this utility model; Figure 2 This is a schematic diagram illustrating the connection structure of the crank pin, bearing, and connecting rod; Figure 3 This is a schematic diagram illustrating the exploded structure between the crank pin, bearing, and connecting rod; Figure 4 This is a cross-sectional view of the connecting rod.

[0023] Reference numerals: 1. Left crank; 2. Middle crank; 3. Right crank; 4. Connecting rod; 5. Crank pin; 6. Bearing; 7. First fixed section; 8. Support section; 9. Second fixed section; 10. Spiral oil guide pattern; 11. Fixing hole; 12. Fixing end; 13. Connecting section; 14. Mounting end; 15. Oil filling groove; 16. Oil inlet hole; 17. Annular oil reservoir; 18. Oil reservoir groove; 19. Oil-absorbing felt; 20. Connecting groove. Detailed Implementation

[0024] The specific embodiments of this utility model will be further described in detail below with reference to the accompanying drawings, so that the technical solution of this utility model can be more easily understood and mastered.

[0025] A crankshaft structure specifically for unmanned aerial vehicles (UAVs) includes a left crank 1, a middle crank 2, a right crank 3, and a connecting rod 4. The left crank 1 is fixedly connected to the middle crank 2, and the middle crank 2 is fixedly connected to the right crank 3 via a crank pin 5. A bearing 6 is rotatably connected to the crank pin 5. This bearing 6 is a needle roller bearing 6.

[0026] The crank pin 5 includes an integrated first fixing section 7, a support section 8, and a second fixing section 9. The two ends of the support section 8 are connected to the first fixing section 7 and the second fixing section 9, respectively. The first fixing section 7 is connected to the middle crank 2, and the second fixing section 9 is connected to the right crank 3. A spiral oil-guiding groove 10 is formed on the outer circumference of the support section 8. The cross-section of the spiral oil-guiding groove 10 is arc-shaped. The depth of the spiral oil-guiding groove 10 is 0.01 mm.

[0027] A fixing hole 11 is provided on the connecting rod 4, and the outer ring of the bearing 6 is fixed in the fixing hole 11 by interference fit.

[0028] The connecting rod 4 includes a fixed end 12, a connecting section 13, and a mounting end 14. The two ends of the connecting section 13 are integrally connected to the fixed end 12 and the mounting end 14, respectively. A fixing hole 11 is formed on the fixed end 12.

[0029] An oil filling groove 15 communicating with a fixing hole 11 is provided on the outer wall of the fixed end 12, and an oil inlet hole 16 is provided on the outer ring of the bearing 6. The position of the oil inlet hole 16 corresponds to the position of the oil filling groove 15 to form a through oil filling path. The opening area of ​​the oil filling groove 15 on the outer wall of the fixed end 12 is larger than its opening area on the inner wall of the fixing hole 11, forming a funnel structure.

[0030] An annular oil reservoir 17 is formed on the inner wall of the fixing hole 11. The annular oil reservoir 17 is connected to the oil injection groove 15, and the fixing hole 11 and the annular oil reservoir 17 are coaxially arranged. The position of the annular oil reservoir 17 covers the position of the oil inlet hole 16, ensuring that the lubricating oil in the annular oil reservoir 17 can enter the bearing 6.

[0031] An oil storage groove 18 is formed on the inner wall of the annular oil storage tank 17. An oil-absorbing felt 19 is provided on the inner wall of the oil storage groove 18. The oil-absorbing felt 19 is embedded in the oil storage groove 18, and the thickness of the oil-absorbing felt 19 is less than the depth of the oil storage groove 18.

[0032] A connecting groove 20 is provided on both sides of the fixed end 12. One end of the connecting groove 20 is connected to the inner wall of the fixed hole 11, and the other end extends to the side end face of the fixed end 12. Multiple connecting grooves 20 are evenly distributed along the circumference of the fixed hole 11 to guide lubricating oil to the contact area between the side of the connecting rod 4 and the middle crank 2 and the right crank 3.

[0033] Of course, the above are just typical examples of this utility model. In addition, this utility model may have many other specific implementation methods. All technical solutions formed by equivalent substitution or equivalent transformation fall within the scope of protection claimed by this utility model.

Claims

1. A crankshaft structure for unmanned aerial vehicles (UAVs), comprising a left crank (1), a middle crank (2), a right crank (3), and a connecting rod (4), wherein the left crank (1) is connected to the middle crank (2), the middle crank (2) is connected to the right crank (3) via a crank pin (5), a bearing (6) is connected to the crank pin (5), and a fixing hole (11) is provided on the connecting rod (4), wherein the bearing (6) is fixed in the fixing hole (11), characterized in that: The connecting rod (4) includes a fixed end (12), a connecting section (13) and an mounting end (14). The two ends of the connecting section (13) are connected to the fixed end (12) and the mounting end (14) respectively. The fixed hole (11) is opened on the fixed end (12). The outer wall of the fixed end (12) is provided with an oil injection groove (15) that communicates with the fixed hole (11). The outer ring of the bearing (6) is provided with an oil inlet hole (16) corresponding to the oil injection groove (15).

2. The crankshaft structure for UAVs according to claim 1, characterized in that: The opening area of ​​the oil injection groove (15) on the outer wall of the fixed end (12) is greater than its opening area on the inner wall of the fixed hole (11).

3. The crankshaft structure for UAVs according to claim 1, characterized in that: A connecting groove (20) is provided on the side wall of the fixed end (12). One end of the connecting groove (20) is connected to the opening of the fixed hole (11), and the other end of the connecting groove (20) is connected to the end face of the fixed end (12).

4. The crankshaft structure for UAVs according to claim 1, characterized in that: An annular oil storage groove (17) is provided on the inner wall of the fixing hole (11), and the annular oil storage groove (17) is connected to the oil injection groove (15).

5. A crankshaft structure for unmanned aerial vehicles according to claim 4, characterized in that: The inner wall of the annular oil storage tank (17) is provided with an oil storage groove (18).

6. A crankshaft structure for unmanned aerial vehicles according to claim 5, characterized in that: Oil-absorbing felt (19) is provided on the inner wall of the oil storage groove (18).

7. A crankshaft structure for UAVs according to any one of claims 1-6, characterized in that: The crank pin (5) includes a first fixed section (7), a support section (8), and a second fixed section (9). The two ends of the support section (8) are connected to the first fixed section (7) and the second fixed section (9) respectively. The first fixed section (7) is connected to the middle crank (2), and the second fixed section (9) is connected to the right crank (3). The outer circumference of the support section (8) is provided with a spiral oil guide pattern (10).

8. A crankshaft structure for unmanned aerial vehicles according to claim 7, characterized in that: The cross-section of the spiral oil guide pattern (10) is arc-shaped.

Images