High speed lubricated engine connecting rod

Abstract

This invention relates to the field of engine technology, and more particularly to a high-speed oil-lubricated engine connecting rod. It includes a connecting rod body, a connecting rod cap, and connecting bolts. The bottom of the connecting rod cap has an oil-pushing section. An annular valve chamber is formed inside the connecting rod cap, and an eccentric valve core with a pumping notch is coaxially mounted within the chamber. This eccentric valve core is configured to oscillate within the chamber using the angular acceleration and oscillating inertia generated by the reciprocating motion of the connecting rod. When the connecting rod is in the downward oil-suction stroke, the pumping notch aligns with the oil inlet channel, drawing in engine oil. When the connecting rod is in the upward compression stroke or under high centrifugal force, the eccentric valve core rotates and misaligns under the action of a counterweight, closing the oil inlet channel. This invention utilizes centrifugal force for self-locking to prevent engine oil from being thrown out, and achieves active pressure lubrication through the pumping effect generated by the oscillating valve core, effectively solving the lubrication failure problem caused by centrifugal oil throwing at high speeds in existing technologies.

Description

Technical Field

[0001] This invention relates to the field of engine technology, and in particular to a high-speed oil-lubricated engine connecting rod. Background Technology

[0002] The connecting rod assembly is a core component connecting the piston and crankshaft, responsible for converting the reciprocating linear motion of the piston into the rotational motion of the crankshaft. During engine operation, the connecting rod big end and crankshaft pin bear enormous alternating loads and high-speed relative friction; therefore, ensuring lubrication of this part is crucial. Traditional lubrication methods are mainly divided into pressure lubrication and splash lubrication. Splash lubrication relies on the structure at the bottom of the connecting rod big end to collect oil mist from the crankcase. However, as engines develop towards higher speeds and higher power densities, the linear velocity of the connecting rod big end increases dramatically. This enormous centrifugal force is directed away from the crankshaft center, making it difficult for external engine oil to enter the connecting rod big end bearing clearance by gravity or even slight impact forces. It may even throw out the existing oil in the bearing clearance, leading to a centrifugal lean oil phenomenon. Especially for motorized two-wheeled vehicle engines (such as motorcycles) operating under more demanding high-speed conditions, motorcycle engines typically have higher maximum speeds (often reaching tens of thousands of RPMs) and more compact crankcase spaces. In addition to requiring high mechanical load-bearing capacity, the connecting rod assembly's centrifugal and lean-fuel issues are further amplified at extremely high speeds, severely impacting engine reliability.

[0003] In the prior art, there are conceptual solutions to address the aforementioned problems by improving the oil passage structure. For example, CN102927118B describes a connecting rod assembly for a high-speed gasoline engine. This application uses an oil-slinging block and a straight-through oil passage at the bottom of the connecting rod cap to guide splashed oil into the bearing. However, this prior art still has shortcomings. First, the oil passage in this solution is a normally open straight-through structure. When the engine is at high speed and the connecting rod is near top dead center, the enormous centrifugal force is far greater than the inertial force of the oil entering, causing the collected oil to be easily thrown out along the straight-through oil passage, making it impossible to retain the oil in the bearing. Second, relying solely on a passive oil-slinging action for oil intake results in extremely low oil pressure entering the bearing. At the moment the connecting rod bearing is subjected to explosive pressure, the low-pressure oil film is prone to rupture, leading to dry friction between the journal and the bearing, which cannot meet the high-pressure oil film requirements of high-performance engines. Furthermore, the oil passages in this prior art document are fixed passages. Metal wear particles in the crankcase can easily accumulate with the engine oil at the corners of the oil passages or at the bearing inlets. Long-term accumulation can lead to oil passage blockage, and once blocked, it will directly cause the connecting rod to seize. Summary of the Invention

[0004] To solve the above-mentioned technical problems, the present invention provides a high-speed oil-lubricated engine connecting rod.

[0005] To achieve the above objectives, the technical solution adopted by the present invention is as follows:

[0006] A high-speed oil-lubricated engine connecting rod includes a connecting rod body, a connecting rod cap, and connecting bolts. The connecting rod cap is connected to the connecting rod body to form a connecting rod big end hole. A connecting rod bearing is installed in the connecting rod big end hole. The bottom of the connecting rod cap has an outwardly extending oil irrigating part. An annular valve cavity is formed on the inner side wall of the connecting rod big end hole. An eccentric valve core is coaxially rotatably installed in the annular valve cavity. An oil pumping notch is formed on the side wall of the eccentric valve core. An oil inlet channel is provided in the connecting rod cap, connecting the oil irrigating part and the annular valve cavity. The oil inlet channel is guided through the oil pumping notch to the gap between the annular valve cavity and the connecting rod bearing.

[0007] The eccentric valve core is configured to reciprocate within the annular valve cavity by utilizing the angular acceleration change and oscillating inertial force generated during the reciprocating motion of the connecting rod body. When the connecting rod body is in the downward oil suction stroke, the oil pumping notch is connected to the oil inlet channel. When the connecting rod body is in the upward compression stroke, the oil pumping notch is misaligned and closed with the oil inlet channel.

[0008] Furthermore, the eccentric valve core has an internal hollow oil storage structure, and the oil pumping notch is a window penetrating the wall thickness of the eccentric valve core. When the eccentric valve core cuts off external oil supply, it supplies oil to the connecting rod bearing through the internal hollow oil storage structure under the action of inertial force. Under high engine speed conditions, the oil inlet channel is open for a very short time, making it difficult for external oil to instantly fill the gap of the connecting rod bearing. The hollow oil storage structure utilizes its hollow volume to pre-store a certain amount of oil at the moment of opening. When the oil inlet channel is closed and the connecting rod is at the end of the exhaust stroke, the connecting rod body is subjected to a huge upward inertial pull, while the oil in the hollow structure generates a relatively downward pressure due to inertial lag, or is squeezed under the action of centrifugal force. At this time, some of the stored oil becomes the friction surface of the connecting rod bearing that is forcibly pressed in, effectively preventing the instantaneous oil shortage phenomenon during the oil inlet interval and ensuring the continuity of the oil film.

[0009] Furthermore, the edge of the pump oil notch has a cutting surface structure. When the pump oil notch and the oil inlet channel are misaligned and closed, the cutting surface structure generates a shearing action, squeezing the oil at the end of the oil inlet channel into the annular valve chamber through the water hammer effect, thus achieving closed pressurization. When the eccentric valve core rotates rapidly under inertial drive and sweeps across the port of the oil inlet channel, the cutting surface structure instantly cuts off the high-speed flowing oil column. According to the principles of fluid mechanics, the flow of liquid has momentum and is incompressible. When the flow path is suddenly cut off, the kinetic energy of the fluid is instantly converted into pressure potential energy. The instantaneously generated pressure pulse amplitude is higher than the natural pressure of external splash lubrication. This pressure pulse acts on the oil that has been sealed in the annular valve chamber, thereby providing pulsed high-pressure oil injection to the connecting rod bearing before the arrival of the burst stroke when the connecting rod body is under the greatest force, significantly improving the bearing's load-bearing capacity.

[0010] Furthermore, the outer surface of the eccentric valve core is provided with several dynamic pressure lubrication grooves. The direction of these grooves is perpendicular to the rotation direction of the eccentric valve core. During the rotation of the eccentric valve core, the oil leaking into the mating clearance establishes a dynamic pressure oil film, suspending the eccentric valve core within the annular valve cavity. This eliminates metal-to-metal contact friction and improves the oscillation response sensitivity. When the eccentric valve core oscillates at high speed within the annular valve cavity, the oil leaking into the mating clearance is drawn into the grooves, generating extremely high dynamic pressure. This lifts the eccentric valve core from the inner wall of the annular valve cavity, achieving liquid suspension support. This eliminates direct metal-to-metal friction and wear, preventing valve core jamming, and also reduces rotational damping, allowing the eccentric valve core to respond sensitively to minute changes in the angular acceleration of the connecting rod body.

[0011] Furthermore, a filter grille is provided on the pump oil inlet. The outer surface of the filter grille is coplanar with the outer circle of the eccentric valve core. The relative shearing motion between the eccentric valve core and the inner wall of the annular valve chamber scrapes away impurities adhering to the surface of the filter grille. When the filter grille passes the edge of the inner wall, a shearing motion occurs, physically scraping away large particles of impurities adhering to the surface of the filter grille, which remain on the outside of the oil inlet channel. Subsequently, during the next oil suction stroke, the impurities are discharged using external turbulence or gravity settling. This solves the common problems of easy clogging and difficult maintenance of microporous filters, significantly improving the maintenance cycle and service life of the connecting rod assembly.

[0012] Furthermore, pressure balance holes are provided at both ends of the annular valve cavity. These pressure balance holes are symmetrically arranged at both ends of the annular valve cavity. These pressure balance holes are used to discharge leaked oil or gas from the axial end face of the eccentric valve core, preventing the formation of air resistance or hydraulic lock on both sides of the eccentric valve core, and ensuring that the eccentric valve core can rotate freely. The pressure balance holes connect the annular valve cavity to the external low-pressure environment, allowing leaked oil or mixed gas to be discharged, maintaining pressure balance on both sides of the end face. This eliminates motion resistance caused by hydraulic viscosity, ensuring the continuity of the eccentric valve core's oscillation.

[0013] Furthermore, the oil quenching section is located on one side of the bottom of the connecting rod cap, and the oil inlet channel cuts into the annular valve cavity tangentially. When the oil quenching section impacts the oil surface in the crankcase at high speed at bottom dead center, engine oil rushes into the oil inlet channel. The tangential cutting ensures that the kinetic energy of the high-speed oil flow directly acts on the inner wall of the eccentric valve core, generating a rotational auxiliary torque consistent with the opening direction of the eccentric valve core. This reduces fluid turbulence resistance and utilizes hydrodynamics to assist the eccentric valve core in overcoming inertia and friction during the oil suction stroke, thereby significantly improving the oil filling efficiency at high speeds.

[0014] Furthermore, the connecting rod body also includes an oil reservoir chamber. One end of the oil reservoir chamber is connected to the annular valve chamber, and the other end guides the small end of the connecting rod. The bottom of the oil reservoir chamber receives the pulsed high-pressure oil from the annular valve chamber and directly permeates to the upper half of the connecting rod big end bore through the internal flow channel. This allows the upper bearing area, which bears the maximum burst pressure during the power stroke, to receive active auxiliary lubrication in addition to the oil film squeezed from the lower bearing, preventing dry friction at the top of the crankshaft pin. On the other hand, the oil reservoir chamber utilizes the enormous axial inertial force generated by the high-speed reciprocating motion of the connecting rod to transport the oil in the chamber upwards along the Y-shaped flow channel. When the oil reaches the outlet of the connecting rod small end, it is ejected or splashed out at high speed due to inertia, forming a dense oil mist environment that directly covers and lubricates the mating surface of the piston pin and the connecting rod small end bushing, solving the technical problem that the connecting rod small end is far from the crankcase oil surface and difficult to obtain sufficient lubrication.

[0015] Furthermore, the oil reservoir has a Y-shaped structure. The top two ends of the Y-shaped structure are connected to the annular valve chamber and the small end of the connecting rod, respectively, while the lower end of the Y-shaped structure extends along the arc surface of the annular valve chamber. The Y-shaped structure connects the lubrication path between the large and small ends of the connecting rod. When the eccentric valve core generates high water hammer pressure at the bottom, the pressure wave not only lubricates the connecting rod bearing downwards but also transmits it upwards to the small end of the connecting rod along the Y-shaped channel. This solves the problem of insufficient lubrication at the small end of the connecting rod due to splashing. Moreover, the flowing oil continuously flushes the inside of the connecting rod during reciprocating motion, carrying away the heat accumulated in the rod body, achieving an internal cooling effect and improving the high-temperature performance of the material.

[0016] Furthermore, an eccentric counterweight is provided on the side of the eccentric valve core opposite to the oil pump inlet, causing the center of gravity of the eccentric valve core to deviate from its rotation center. This utilizes the centrifugal force generated by the engine speed to achieve periodic closure of the oil inlet channel. The eccentric counterweight results in uneven mass distribution of the eccentric valve core, and the centrifugal force it experiences generates a large unidirectional rotational torque on the eccentric valve core. This causes the eccentric valve core to rotate stably in response to changes in centrifugal force during the movement of the connecting rod body, thereby controlling the periodic change of the position of the oil pump inlet relative to the position of the oil inlet channel.

[0017] Furthermore, the connecting rod bearing includes an upper bearing and a lower bearing. The upper bearing is installed inside the connecting rod big end bore of the connecting rod body, and the lower bearing is installed inside the connecting rod cap. Since the lower bearing directly bears the upward inertial tensile load of the connecting rod, this area is the negative pressure zone where the oil film is most prone to rupture. Injecting the established high-pressure oil film directly into this area via the shortest path can replenish oil film loss most quickly. Simultaneously, as the crankshaft rotates, the oil film at the lower bearing is carried into the load-bearing area of ​​the upper bearing, thereby achieving lubrication of the entire connecting rod system.

[0018] Furthermore, the arc length of the oil pump notch is between 1 / 8 and 1 / 4 of the circumference of the eccentric valve core. When the connecting rod moves downward, the notch needs to allow the viscous oil to fully fill the annular valve cavity within a very short time. If the opening of the oil pump notch is too small, the flow resistance will be too high, and cavitation may easily occur. When the connecting rod body moves upward, the centrifugal force is large, and at this time the connecting rod body will swing left and right. The solid wall of the eccentric valve core must completely cover the oil inlet channel to prevent high-pressure oil leakage.

[0019] Furthermore, both ends of the connecting rod body and the connecting rod cap are provided with corresponding threaded holes, and the connecting rod body and the connecting rod cap are fixedly connected by connecting bolts and threaded holes. The use of high-strength bolts in conjunction with threaded holes and locating pins provides sufficient preload to resist the tendency of the connecting rod cap to separate, ensuring structural integrity, and also ensuring that the annular valve cavity inside the connecting rod cap maintains good cylindricity even under extreme stress.

[0020] Compared with the prior art, the present invention has the following beneficial effects:

[0021] 1. The present invention has an eccentric valve core rotatably installed inside the connecting rod, so that when the connecting rod moves to the position where the maximum centrifugal force is generated, the centrifugal force drives the valve core to close the oil inlet channel, ensuring that the oil is locked in the valve cavity and not thrown out.

[0022] 2. This invention utilizes the angular acceleration of the connecting rod swing to drive the eccentric valve core to open and close periodically. At the instant the valve core changes from open to closed, the cutting surface of the oil pump notch generates a shearing action. Combined with the water hammer effect, the oil at the end of the oil inlet channel is forced into the bearing gap, so that the oil in the bearing has a higher initial pressure and can withstand a greater burst load.

[0023] 3. During the oscillation process, the eccentric valve core of the present invention uses the leaked oil to establish an oil film on its surface through the hydrodynamic lubrication groove, thereby realizing the non-contact suspension rotation of the valve core and avoiding mechanical wear. At the same time, when the edge of the pump oil notch periodically sweeps across the oil inlet channel, it will physically shear and scrape the impurities in the oil, preventing large particles of impurities from entering the precision bearing gap and playing a self-cleaning role.

[0024] 4. The connecting rod structure described in this invention is suitable for compact power platforms that require high strength, high speed, and lightweight design, and is especially suitable for high-performance motorcycle engines. Through active mechanical oil pumping and centrifugal force locking mechanism, it solves the problem of bearing lubrication under extreme operating conditions of motorcycle engines at tens of thousands of RPM, significantly improves the tensile and compressive strength and anti-cylinder wear ability of the connecting rod assembly, and extends the maintenance cycle of high-load power equipment. Attached Figure Description

[0025] Figure 1 This is an exploded view of the present invention;

[0026] Figure 2 This is a schematic diagram of the eccentric valve core.

[0027] Figure 3 This is a schematic diagram of the planar structure of the present invention;

[0028] Figure 4 This is a planar sectional view of the present invention;

[0029] Attached diagram labels: 1-Connecting rod body, 2-Connecting rod cap, 3-Connecting bolt, 4-Connecting rod big end hole, 5-Connecting rod bearing, 501-Upper bearing, 502-Lower bearing, 6-Oil quenching section, 7-Annular valve chamber, 8-Eccentric valve core, 9-Pump oil notch, 10-Oil inlet channel, 11-Dynamic pressure lubrication groove, 12-Filter grille, 13-Pressure balance hole, 14-Oil reservoir, 15-Threaded hole. Detailed Implementation

[0030] To make the objectives, technical solutions, and advantages of the present invention clearer, the present invention will be further described in detail below with reference to the embodiments and accompanying drawings. The illustrative embodiments and descriptions of the present invention are only used to explain the present invention and are not intended to limit the present invention.

[0031] Example 1, as Figures 1-4 As shown, this invention discloses a high-speed oil-lubricated engine connecting rod, including a connecting rod body 1, a connecting rod cap 2, and connecting bolts 3. The connecting rod cap 2 is connected to the connecting rod body 1 to form a connecting rod big end hole 4. A connecting rod bearing 5 is installed in the connecting rod big end hole 4. The bottom of the connecting rod cap 2 is provided with an outwardly extending oil irrigating part 6. An annular valve cavity 7 is opened on the inner side wall of the connecting rod big end hole 4. An eccentric valve core 8 is coaxially rotatably installed in the annular valve cavity 7. An oil pumping notch 9 is opened on the side wall of the eccentric valve core 8. An oil inlet channel 10 is provided in the connecting rod cap 2 to connect the oil irrigating part 6 and the annular valve cavity 7. The oil inlet channel 10 is guided through the oil pumping notch 9 to the gap between the annular valve cavity 7 and the connecting rod bearing 5.

[0032] The eccentric valve core 8 is configured to reciprocate within the annular valve cavity 7 by utilizing the angular acceleration change and oscillating inertial force generated during the reciprocating motion of the connecting rod body 1. When the connecting rod body 1 is in the downward oil suction stroke, the oil pumping notch 9 is connected to the oil inlet channel 10. When the connecting rod body 1 is in the upward compression stroke, the oil pumping notch 9 is misaligned and closed with the oil inlet channel 10.

[0033] The eccentric valve core 8 has an internal hollow oil storage structure, and the pumping notch 9 is a window penetrating the wall thickness of the eccentric valve core 8. When the eccentric valve core 8 cuts off external oil supply, it supplies oil to the connecting rod bearing 5 through the internal hollow oil storage structure under the action of inertial force. Specifically, under high engine speed conditions, the opening time of the oil inlet channel 10 is extremely short, making it difficult for external engine oil to instantly fill the gap of the connecting rod bearing 5. The hollow oil storage structure utilizes its hollow volume to pre-store a certain amount of engine oil at the moment of opening. When the oil inlet channel 10 is closed and the connecting rod is at the end of the exhaust stroke (upward), the connecting rod body 1 is subjected to a huge upward inertial pull, while the engine oil in the hollow structure generates a relatively downward pressure due to inertial lag, or is squeezed under the action of centrifugal force. At this time, some of the stored engine oil becomes the friction surface of the connecting rod bearing 5 that is forcibly pressed in, effectively preventing the instantaneous oil shortage phenomenon during the oil inlet interval and ensuring the continuity of the oil film.

[0034] The edge of the pump oil notch 9 has a cutting surface structure. When the pump oil notch 9 and the oil inlet channel 10 are misaligned and closed, the cutting surface structure generates a shearing action, squeezing the oil at the end of the oil inlet channel 10 into the annular valve chamber 7 through the water hammer effect, thus achieving closed pressurization. Specifically, the cutting surface structure is wedge-shaped or blade-shaped. When the eccentric valve core 8 rotates rapidly under inertial drive and sweeps past the port of the oil inlet channel 10, the cutting surface structure instantly cuts off the high-speed flowing oil column. According to the principles of fluid mechanics, the flow of liquid has momentum and is incompressible. When the flow path is suddenly cut off, the kinetic energy of the fluid is instantly converted into pressure potential energy, i.e., the water hammer effect is generated. The amplitude of the instantaneously generated pressure pulse is much higher than the natural pressure of external splash lubrication. This pressure pulse acts on the oil that has been sealed in the annular valve chamber 7, thereby providing pulsed high-pressure oil injection to the connecting rod bearing 5 before the arrival of the burst stroke when the connecting rod body 1 is under the greatest force, significantly improving the bearing's load-bearing capacity. Preferably, the eccentric valve core 8 has a radial wall thickness of 3-8 mm, and a stepped surface with radial depth is formed between the pumping notch 9 and the solid thick wall. When the eccentric valve core 8 rotates relative to the annular valve cavity 7 under inertial drive, the eccentric valve core 8 rotates rapidly to close the oil inlet channel 10. At this time, the solid thick wall located behind the pumping notch 9 circumferentially sweeps and squeezes the oil layer retained near the port of the oil inlet channel 10. Utilizing the incompressibility and viscous adhesion of the fluid, this portion of oil that might otherwise overflow or flow back is forcibly pushed into the depth of the annular valve cavity 7, effectively improving the volumetric efficiency of the annular valve cavity 7.

[0035] The outer surface of the eccentric valve core 8 is provided with several dynamic pressure lubrication grooves 11. The direction of the dynamic pressure lubrication grooves 11 is perpendicular to the rotation direction of the eccentric valve core 8. During the rotation of the eccentric valve core 8, the oil leaking into the mating gap between the eccentric valve core and the annular valve cavity establishes a dynamic pressure oil film, suspending the eccentric valve core 8 within the annular valve cavity 7, eliminating metal-to-metal contact friction and improving the oscillation response sensitivity. Specifically, the dynamic pressure lubrication grooves 11 are shallow grooves with a depth of 5-20 micrometers, on the micrometer scale. When the eccentric valve core 8 oscillates at high speed within the annular valve cavity 7, the oil leaking into the mating gap is drawn into the grooves, generating extremely high dynamic pressure. This lifts the eccentric valve core 8 from the inner wall of the annular valve cavity 7, achieving liquid suspension support. This eliminates direct metal-to-metal friction and wear, preventing valve core jamming, and greatly reduces rotational damping, making the eccentric valve core 8 a nearly frictionless sensitive element, allowing for a sensitive response to minute changes in the angular acceleration of the connecting rod body 1.

[0036] A filter grille 12 is provided on the oil pump notch 9. The outer surface of the filter grille 12 is coplanar with the outer circle of the eccentric valve core 8. The relative shearing motion between the eccentric valve core 8 and the inner wall of the annular valve chamber 7 scrapes away impurities adhering to the surface of the filter grille 12. Specifically, engine oil, after long-term use, contains metal shavings or carbon deposits, which can easily clog the oil passages inside the connecting rod. When the filter grille 12 passes the inner wall edge, a shearing motion occurs, physically scraping away large particles of impurities adhering to the surface of the filter grille 12, which remain on the outside of the oil inlet channel 10. Subsequently, during the next oil suction stroke, the impurities are discharged by external turbulence or gravity settling. This solves the common problems of easy clogging and difficult maintenance of microporous filters, significantly improving the maintenance cycle and service life of the connecting rod assembly.

[0037] The annular valve chamber 7 has pressure balance holes 13 at both ends, symmetrically arranged. These holes discharge leaked oil or gas from the axial end face of the eccentric valve core 8, preventing air resistance or hydraulic lock-up on both sides and ensuring free rotation of the eccentric valve core 8. Specifically, during high-pressure pumping, some high-pressure oil may leak axially through the clearance into the small space between the two end faces of the eccentric valve core 8 and the inner wall of the connecting rod cover 2. Without the pressure balance holes 13, this accumulated oil would form a closed high-pressure dead chamber, generating a huge axial thrust that presses the eccentric valve core 8 tightly against the end wall, preventing rotation. The pressure balance holes 13 connect the annular valve chamber 7 to the external low-pressure environment, allowing leaked oil or mixed gas to escape and maintaining pressure balance on both sides of the end face. This eliminates motion resistance caused by hydraulic viscosity, ensuring the continuity of the eccentric valve core 8's oscillation.

[0038] The oil quenching section 6 is located on one side of the bottom of the connecting rod cover 2, and the oil inlet channel 10 cuts into the annular valve chamber 7 tangentially. Specifically, when the oil quenching section 6 impacts the oil surface in the crankcase at high speed at bottom dead center, the engine oil rushes into the oil inlet channel 10 at an extremely high relative velocity. The tangential cutting allows the kinetic energy of the high-speed oil flow to directly act on the inner wall of the eccentric valve core 8, generating a rotational auxiliary torque consistent with the opening direction of the eccentric valve core 8. This reduces fluid turbulence resistance and utilizes hydrodynamics to assist the eccentric valve core 8 in overcoming inertia and friction during the oil suction stroke, thereby significantly improving the oil filling efficiency at high speeds.

[0039] An eccentric counterweight is provided on the eccentric valve core 8 opposite to the oil pump notch 9, causing the center of gravity of the eccentric valve core 8 to deviate from its rotation center. This utilizes the centrifugal force generated by the engine speed to achieve periodic closure of the oil inlet channel 10. Specifically, the eccentric counterweight causes uneven mass distribution of the eccentric valve core 8, and the centrifugal force it experiences generates a large unidirectional rotational torque on the eccentric valve core 8. This causes the eccentric valve core 8 to rotate stably following the changes in centrifugal force during the movement of the connecting rod body 1, thereby controlling the periodic change of the position of the oil pump notch 9 relative to the position of the oil inlet channel 10.

[0040] The connecting rod bearing 5 includes an upper bearing 501 and a lower bearing 502. The upper bearing 501 is installed inside the connecting rod big end hole 4 of the connecting rod body 1, and the lower bearing 502 is installed inside the connecting rod cover 2. Specifically, since the lower bearing 502 directly bears the upward inertial tensile load of the connecting rod, this area is the negative pressure zone where the oil film is most prone to rupture. Injecting the established high-pressure oil film directly into this area through the shortest path can replenish the oil film loss as quickly as possible. At the same time, as the crankshaft rotates, the oil film at the lower bearing 502 will be carried into the bearing area of ​​the upper bearing 501, thereby achieving lubrication of the entire connecting rod system.

[0041] Both ends of the connecting rod body 1 and the connecting rod cover 2 are provided with corresponding threaded holes 15. The connecting rod body 1 and the connecting rod cover 2 are fixedly connected by connecting bolts 3 and threaded holes 15. Specifically, in high-speed engines, the connecting rod big end hole 4 will undergo microscopic elliptic deformation under inertial force, which may cause the eccentric valve core 8 to jam or fail to seal. The use of high-strength bolts 3 in conjunction with precision threaded holes 15 and locating pins provides sufficient preload to resist the separation tendency of the connecting rod cover 2, ensuring the integrity of the structure, and also ensuring that the annular valve cavity 7 inside the connecting rod cover 2 can maintain good cylindricity under extreme stress.

[0042] The specific working principle of this application is as follows:

[0043] Downward oil suction phase: As the connecting rod moves downward and approaches the bottom dead center, the oil churning section 6 impacts the oil in the crankcase. At this time, affected by gravity and the angular acceleration generated by the connecting rod's swing, the eccentric valve core 8 rotates relative to the connecting rod cover 2. The eccentric counterweight is located at the rear end in the direction of motion, i.e., the upper end of the annular valve chamber 7, causing the oil pumping notch 9 to be located at the lower end of the annular valve chamber 7, thereby aligning the oil pumping notch 9 with the oil inlet channel 10. Under the action of impact dynamic pressure, external oil flows tangentially into the annular valve chamber 7 and the hollow interior of the eccentric valve core 8.

[0044] Upward locking and pressurization stage: When the connecting rod passes the bottom dead center and begins to move upward, a large centrifugal force is generated at the big end of the connecting rod, and the connecting rod swing angle changes in the opposite direction. At this time, the eccentric counterweight is positioned at the rear of the movement under the action of centrifugal force, that is, at the lower end of the annular valve chamber 7, causing the oil pump notch 9 to be misaligned with the oil inlet channel 10, thus achieving closure. At the instant of closure, the shearing action of the cutting surface structure generates a water hammer effect, causing the oil pressure inside the chamber to rise sharply.

[0045] As the connecting rod continues to move upward, the oil inlet passage 10 remains closed to prevent the oil from being thrown out by centrifugal force. At this time, the high-pressure oil locked in the annular valve chamber 7, as well as the oil in the hollow oil reservoir, are squeezed into the gap between the connecting rod bearing 5 and the crankshaft pin under the action of the huge reciprocating inertial force of the connecting rod, forming a high-load-bearing oil film.

[0046] It should be noted that the connecting rod body 1 provided in this embodiment is not only suitable for conventional general-purpose small gasoline engines, but more preferably for high-strength motorcycle engines that need to withstand high burst pressure. Since the operating speed of motorcycle engines often spans the range of 8000-14000 rpm, traditional passive splash lubrication can no longer meet its requirements. The connecting rod body 1 and connecting rod cap 2 of this invention are made of high-strength forged alloy material, and together with the internal eccentric valve core 8 structure, they can meet the needs of such high-speed application scenarios.

[0047] Example 2: Based on Example 1, this example proposes a high-speed oil-lubricated engine connecting rod with an oil reservoir chamber.

[0048] The connecting rod body 1 also has an oil reservoir 14 inside its cavity. One end of the oil reservoir 14 is connected to the annular valve chamber 7, and the other end of the oil reservoir 14 guides the small end of the connecting rod. Specifically, the bottom of the oil reservoir 14 receives the pulsed high-pressure oil from the annular valve chamber 7 and directly permeates through the internal flow channel to the upper half of the connecting rod big end hole 4 (i.e., the back and inner surface of the upper bearing 501). This allows the area of ​​the upper bearing 501, which bears the maximum burst pressure during the power stroke, to receive active auxiliary lubrication in addition to the oil film squeezed by the lower bearing 502, preventing dry friction at the top of the crankshaft pin. On the other hand, the oil reservoir 14 utilizes the huge axial inertial force generated by the high-speed reciprocating motion of the connecting rod to transport the oil in the cavity upward along the Y-shaped flow channel. When the oil reaches the outlet of the small end of the connecting rod, it is ejected or splashed out at high speed due to inertia, forming a dense oil mist environment that directly covers and lubricates the mating surfaces of the piston pin and the small end bushing. This solves the technical problem that the small end of the connecting rod is far from the oil surface in the crankcase and is difficult to obtain sufficient lubrication.

[0049] The oil storage chamber 14 has a Y-shaped structure. The top two ends of the Y-shaped structure are connected to the annular valve chamber 7 and the small end of the connecting rod, respectively. The lower end of the Y-shaped structure extends along the arc surface of the annular valve chamber 7. Specifically, the Y-shaped structure connects the lubrication links between the large and small ends of the connecting rod. When the eccentric valve core 8 generates high water hammer pressure at the bottom, the pressure wave not only lubricates the connecting rod bearing 5 downwards but also transmits it upwards to the small end of the connecting rod along the Y-shaped channel. This solves the problem of insufficient lubrication at the small end of the connecting rod due to splashing. Furthermore, the flowing oil continuously flushes the inside of the connecting rod during reciprocating motion, carrying away the heat accumulated in the rod body, achieving an internal cooling effect and improving the high-temperature performance of the material.

[0050] In high power density applications such as motorcycle engines, the piston and connecting rod small end are subjected to extremely high thermal loads. This invention not only solves the problem of insufficient lubrication of the connecting rod small end due to splash lubrication, but also ensures that the flowing oil continuously flushes the inside of the connecting rod during reciprocating motion, carrying away the heat accumulated in the rod body and achieving an internal cooling effect. This further protects the high-temperature mechanical properties of the connecting rod material under high-speed and high-intensity conditions.

[0051] Example 3: Based on Example 1, this example proposes an eccentric valve core for connecting rods of high-speed oil-lubricated engines.

[0052] The arc length of the pump oil notch 9 is between 1 / 8 and 1 / 4 of the circumference of the eccentric valve core 8. Specifically, when the connecting rod moves downward (oil suction stroke), the notch needs to allow the viscous oil to fully fill the annular valve cavity 7 within a very short time. If the opening of the pump oil notch 9 is too small, the flow resistance will be too high, and cavitation may easily occur. When the connecting rod body 1 moves upward, the centrifugal force is large, and at this time the connecting rod body 1 will swing left and right, with a swing angle of approximately ±15°-20°. The solid wall of the eccentric valve core 8 must completely cover the oil inlet channel 10 to prevent high-pressure oil leakage.

[0053] The swing range of the connecting rod is approximately 40°. The eccentric valve core 8 rotates due to inertia, and its swing amplitude is usually slightly greater than or lags behind the swing angle of the connecting rod body 1. If the swing amplitude of the eccentric valve core 8 relative to the connecting rod cover 2 is ±30°, in order to ensure no oil leakage under high pressure, the solid closed part of the eccentric valve core 8 (i.e., 360° minus the opening angle of the pump oil notch 9) must be much larger than this swing amplitude. If the notch angle is less than 45°, a throttling orifice will be formed under high-speed flow, hindering oil inlet. If it is greater than 90°, the remaining sealing wall area is 270°, which may easily lead to poor sealing and oil being thrown out when the eccentric valve core 8 shakes violently.

[0054] Therefore, within the 45°-90° range, fluid filling efficiency and dynamic seal reliability are in a balance zone. Preferably, when the opening angle of the pump oil notch 9 is 60°, its opening is sufficient to cover the diameter of the oil inlet channel 10, ensuring smooth oil inlet flow. At the same time, a 300° solid wall surface is left for sealing. Even if the valve core experiences severe oscillation of ±45°, there is still sufficient wall surface to block the oil inlet, resulting in the highest reliability.

[0055] Of course, the present invention may have many other embodiments. Without departing from the spirit and essence of the present invention, those skilled in the art can make various corresponding changes and modifications according to the present invention, but these corresponding changes and modifications should all fall within the protection scope of the appended claims.

Claims

1. A high-speed oil-lubricated engine connecting rod, comprising a connecting rod body (1), a connecting rod cap (2), and connecting bolts (3), wherein the connecting rod cap (2) is connected to the connecting rod body (1) to form a connecting rod big end hole (4), and a connecting rod bearing (5) is installed in the connecting rod big end hole (4), characterized in that, The bottom of the connecting rod cover (2) is provided with an outwardly extending oil stimulating part (6), and the inner side wall of the connecting rod big end hole (4) is provided with an annular valve cavity (7). An eccentric valve core (8) is coaxially rotatably installed in the annular valve cavity (7). The side wall of the eccentric valve core (8) is provided with an oil pumping notch (9). The connecting rod cover (2) is provided with an oil inlet channel (10) connecting the oil stimulating part (6) and the annular valve cavity (7). The oil inlet channel (10) guides the oil to the gap between the annular valve cavity (7) and the connecting rod bearing (5) through the oil pumping notch (9). The eccentric valve core (8) has an internal hollow oil storage structure. The pumping notch (9) is a window that penetrates the wall thickness of the eccentric valve core (8). When the external oil inlet is cut off, the eccentric valve core (8) supplies oil to the connecting rod bearing (5) under the action of inertial force through the internal hollow oil storage structure. The edge of the pumping notch (9) is a cutting surface structure. When the pumping notch (9) and the oil inlet channel (10) are misaligned and closed, the cutting surface structure generates a shearing action, squeezing the oil at the end of the oil inlet channel (10) into the pumping notch. Inside the annular valve cavity (7), several dynamic pressure lubrication grooves (11) are provided on the outer surface of the eccentric valve core (8). The direction of the dynamic pressure lubrication grooves (11) is perpendicular to the rotation direction of the eccentric valve core (8). They are used to establish a dynamic pressure oil film by utilizing the oil leaking into the fit gap between the eccentric valve core (8) and the annular valve cavity (7) during the rotation of the eccentric valve core (8). An eccentric counterweight is provided on the eccentric valve core (8) on the side opposite to the oil pump notch (9), so that the center of gravity of the eccentric valve core (8) deviates from its rotation center. The eccentric valve core (8) is configured to: utilize the angular acceleration change and swing inertial force generated by the connecting rod body (1) during the reciprocating motion to swing back and forth in the annular valve cavity (7). When the connecting rod body (1) is in the downward oil suction stroke, the oil pumping notch (9) is connected to the oil inlet channel (10). When the connecting rod body (1) is in the upward compression stroke, the oil pumping notch (9) is misaligned and closed with the oil inlet channel (10).

2. A high-rotational-speed lubricated engine connecting rod according to claim 1, characterized in that: The oil pump notch (9) is provided with a filter grille (12), and the outer surface of the filter grille (12) is coplanar with the outer circle of the eccentric valve core (8).

3. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: The annular valve cavity (7) is provided with pressure balance holes (13) at both ends. The pressure balance holes (13) are symmetrically arranged at both ends of the annular valve cavity (7). The pressure balance holes (13) are used to discharge leaked oil or gas at the axial end face of the eccentric valve core (8).

4. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: The oil inlet section (6) is located on one side of the bottom of the connecting rod cover (2), and the oil inlet channel (10) cuts into the annular valve chamber (7) along the tangential direction.

5. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: The inner cavity of the connecting rod body (1) is also provided with an oil storage chamber (14), one end of which is connected to the annular valve chamber (7), and the other end of which guides the small end of the connecting rod.

6. A high-speed oil-lubricated engine connecting rod according to claim 5, characterized in that: The oil storage chamber (14) has a Y-shaped structure. The top two ends of the Y-shaped structure are connected to the annular valve chamber (7) and the small end of the connecting rod, respectively. The lower end of the Y-shaped structure is attached to the arc surface of the annular valve chamber (7).

7. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: The connecting rod bearing (5) includes an upper bearing (501) and a lower bearing (502). The upper bearing (501) is installed inside the connecting rod big end hole (4) of the connecting rod body (1), and the lower bearing (502) is installed inside the connecting rod cover (2).

8. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: The arc length of the pump oil notch (9) is between 1 / 8 and 1 / 4 of the circumference of the eccentric valve core (8).

9. A high-speed oil-lubricated engine connecting rod according to claim 1, characterized in that: Both ends of the connecting rod body (1) and the connecting rod cover (2) are provided with corresponding threaded holes (15). The connecting rod body (1) and the connecting rod cover (2) are fixedly connected by the cooperation of the connecting bolts (3) and the threaded holes (15).

Images