Motorcycle crankshaft

Abstract

The utility model relates to a crankshaft technical field, concretely relates to a motorcycle crankshaft, including left main shaft neck and right main shaft neck, be equipped with rolling bearing on left main shaft neck, be equipped with keyway on right main shaft neck, still include crankshaft device, the crankshaft device includes left sectorial crank, right sectorial crank, crank pin, connecting rod, outer circle bulge and lubricating assembly, left sectorial crank is integrally formed with left main shaft neck, and rolling bearing is close to left sectorial crank, right sectorial crank is integrally formed with right main shaft neck, and crank pin is fixedly installed between left sectorial crank and right sectorial crank, and connecting rod is rotated with the cooperation of crank pin through roller bearing, and outer circle bulge sets up in connecting rod outside, and lubricating assembly provides lubrication passage, through the setting of sectorial structure of left sectorial crank and right sectorial crank, the vibration and noise of engine have been reduced from the root, and at the same time, set up outer circle bulge in connecting rod, significantly increased the section modulus and longitudinal bending stability of connecting rod when bearing maximum compression force.

Description

Technical Field

[0001] This utility model relates to the field of crankshaft technology, and in particular to a motorcycle crankshaft. Background Technology

[0002] In a motorcycle engine, the crankshaft is the core component that converts the reciprocating motion of the piston and connecting rod into rotational motion. Its dynamic balance and structural reliability directly determine the engine's vibration level, noise level, and service life. Currently, common motorcycle crankshafts typically employ a modular structure, mainly consisting of left and right shafts, left and right cranks, and crankpins connecting the two. Connecting rods are hinged to the crankpins. For the purpose of simplifying manufacturing, the cranks are often manufactured as a plate-like structure that is either a full circle or nearly a full circle; meanwhile, to meet strength requirements, the connecting rods often adopt traditional I-shaped or H-shaped cross-section structures.

[0003] However, conventional crankshaft structures with full or near-full circular shapes are difficult to integrate with effective counterweights due to their symmetrical shape. As a result, their effect on balancing the rotational and reciprocating inertial forces generated by the high-speed movement of the piston and connecting rod assembly is minimal, and they cannot effectively suppress engine vibration and noise. Secondly, traditional connecting rods with constant or near-constant cross-sections are prone to longitudinal bending instability when subjected to huge compressive forces under high engine load conditions. Utility Model Content

[0004] The purpose of this invention is to provide a motorcycle crankshaft that solves the problem that conventional circular or near-circular crankshaft structures, due to their symmetrical shape, are difficult to integrate with effective counterweights. This results in minimal balancing effect on the rotational and reciprocating inertial forces generated by the high-speed movement of the piston and connecting rod assembly, thus failing to effectively suppress engine vibration and noise. Secondly, traditional connecting rods with uniform or near-uniform cross-sections are prone to longitudinal bending instability under high engine loads and immense compressive forces.

[0005] To achieve the above objectives, this utility model provides a motorcycle crankshaft, including a left main journal and a right main journal. A rolling bearing is provided on the left main journal, and a keyway is provided on the right main journal. The crankshaft also includes a crank assembly comprising a left sector crank, a right sector crank, a crank pin, a connecting rod, an outer circular protrusion, and a lubrication assembly. The left sector crank is integrally formed with the left main journal. The rolling bearing is located close to the left sector crank. The right sector crank is integrally formed with the right main journal. The crank pin is fixedly installed between the left and right sector cranks. The connecting rod rotates with the crank pin via a needle roller bearing. The outer circular protrusion is located on the outer side of the connecting rod. The lubrication assembly provides a lubrication channel.

[0006] The lubrication assembly includes a main oil passage, a connecting oil passage, and a lubricating oil passage. The main oil passage is located inside the right main journal. The connecting oil passage is located inside the right main journal and communicates with it. The lubricating oil passage is located inside the crank pin and communicates with it.

[0007] The keyway is also provided with a positioning hole, which extends to the inside of the right spindle journal.

[0008] The right spindle journal is also provided with an annular groove, which is located on the side of the right spindle journal near the keyway.

[0009] The left main journal is also provided with a timing sprocket, which is located on the side of the left main journal close to the rolling bearing.

[0010] This invention relates to a motorcycle crankshaft. In use, the reciprocating movement of the piston in the connecting rod causes the connecting rod to oscillate. The connecting rod then converts this oscillation into rotational motion of the left and right sector cranks, driving the left and right main journals to rotate. During this process, lubricating oil enters through the lubrication assembly and lubricates the needle roller bearings and the connecting rod. Furthermore, the sector-shaped structure of the left and right sector cranks creates an asymmetrical mass distribution, with the protruding sector corners forming counterweights. This allows the centrifugal force generated during rotation to efficiently balance the rotational inertia force generated by the crank pins and the connecting rod mass, and partially offset the reciprocating inertia force of the piston assembly. This significantly reduces engine vibration and noise at the source. Simultaneously, the outer circumference protrusion on the connecting rod significantly increases its section modulus and longitudinal bending stability when subjected to maximum compressive force (combustion detonation). Attached Figure Description

[0011] To more clearly illustrate the technical solutions in the embodiments of this application or the prior art, the accompanying drawings used in the description of the embodiments or the prior art will be briefly introduced below.

[0012] Figure 1 This is a schematic diagram of the overall structure of a motorcycle crankshaft according to this utility model.

[0013] Figure 2 This is a schematic diagram of the right sector-shaped crank of this utility model.

[0014] In the diagram: 101-Left main journal, 102-Right main journal, 103-Rolling bearing, 104-Keyway, 106-Left sector crank, 107-Right sector crank, 108-Crank pin, 109-Connecting rod, 110-Outer circle protrusion, 111-Needle roller bearing, 112-Main oil passage, 113-Connecting oil passage, 114-Lubricating oil passage, 115-Positioning hole, 116-Annular groove, 117-Timing sprocket. Detailed Implementation

[0015] The embodiments of the present invention are described in detail below. Examples of the embodiments are shown in the accompanying drawings. The embodiments described below with reference to the accompanying drawings are exemplary and intended to explain the present invention, but should not be construed as limiting the present invention.

[0016] The embodiment of this application is as follows:

[0017] Please see Figure 1-2 , Figure 1 This is a schematic diagram of the overall structure of a motorcycle crankshaft according to this utility model. Figure 2 This is a schematic diagram of the right sector-shaped crank of this utility model.

[0018] This utility model provides a motorcycle crankshaft, including a left main journal 101 and a right main journal 102, and a crankshaft assembly. The crankshaft assembly includes a left sector crank 106, a right sector crank 107, a crank pin 108, a connecting rod 109, an outer circular protrusion 110, and a lubrication assembly. The lubrication assembly includes a main oil passage 112, a connecting oil passage 113, and a lubrication oil passage 114. The keyway 104 is also provided with a positioning hole 115. The right main journal 102 is also provided with an annular groove 116, and the left main journal 101 is also provided with a timing sprocket 117. The aforementioned solution solves the problem that conventional full-circle or near-full-circle crank structures, due to their symmetrical shape, are difficult to integrate effective counterweights, resulting in minimal balancing effect on the rotational inertia force and reciprocating inertia force generated by the high-speed movement of the piston and connecting rod assembly, and thus cannot effectively suppress engine vibration and noise. Secondly, traditional connecting rods with uniform or near-uniform cross-sections are prone to longitudinal bending instability when subjected to enormous compressive forces under high engine load conditions.

[0019] In this embodiment, the fan-shaped structure of the left fan-shaped crank 106 and the right fan-shaped crank 107 significantly reduces engine vibration and noise at the source. The outer circle protrusion 110 of the connecting rod 109 increases the section modulus and longitudinal bending stability of the connecting rod 109.

[0020] The left sector crank 106 is integrally formed with the left main journal 101. The rolling bearing 103 is close to the left sector crank 106. The right sector crank 107 is integrally formed with the right main journal 102. The crank pin 108 is fixedly installed between the left sector crank 106 and the right sector crank 107. The connecting rod 109 is rotatably engaged with the crank pin 108 through the needle roller bearing 111. The outer circle protrusion 110 is provided on the outside of the connecting rod 109. The lubrication assembly provides a lubrication channel. Both the left sector crank 106 and the right sector crank 107 are sector-shaped structures. The axis of the crank pin 108 is parallel to the axes of the left main journal 101 and the right main journal 102. The connecting rod 109 is interference-fitted with the outer ring of the needle roller bearing 111. The crank pin 108 and the needle roller bearing 107 are interlocked. The inner ring of bearing 111 is interference-fitted, and the lubrication assembly facilitates the entry of lubricating oil into the needle roller bearing 111 and the sidewalls between the connecting rod 109 and the left and right sector cranks 106 and 107. The sector structure of the left and right sector cranks 106 and 107 creates an asymmetrical mass distribution, with the protruding sector corners forming counterweights. This allows the centrifugal force generated during rotation to efficiently balance the rotational inertia force generated by the crank pin 108 and the connecting rod 109, and partially offset the reciprocating inertia force of the piston assembly. This significantly reduces engine vibration and noise at the source. At the same time, the outer protrusion 110 on the connecting rod 109 significantly increases the section modulus and longitudinal bending stability of the connecting rod 109 when subjected to maximum compressive force (combustion detonation pressure).

[0021] Secondly, the main oil passage 112 is located inside the right main journal 102; the connecting oil passage 113 is located inside the right main journal 102 and communicates with the connecting oil passage 113; the lubricating oil passage 114 is located inside the crank pin 108 and communicates with the connecting oil passage 113. The connecting oil passage 113 is inclined and located between the main oil passage 112 and the lubricating oil passage 114. Lubricating oil enters the connecting oil passage 113 through the main oil passage 112 and enters the lubricating oil passage 114 through the connecting oil passage 113, thereby achieving lubrication of the needle roller bearing 111 and the sidewalls between the connecting rod 109 and the left sector crank 106 and the right sector crank 107.

[0022] Secondly, the positioning hole 115 extends to the inner side of the right main journal 102, and the positioning hole 115 is used for auxiliary positioning of other accessories.

[0023] Furthermore, the annular groove 116 is located on the side of the right spindle journal 102 near the keyway 104. The annular groove 116 is used to install an oil seal, forming a rotary dynamic seal to prevent oil leakage.

[0024] Finally, the timing sprocket 117 is located on the side of the left main journal 101 near the rolling bearing 103. The timing sprocket 117 is interference-fitted with the left main journal 101, and the timing sprocket 117 facilitates the driving of the gas components by means of a chain.

[0025] In this embodiment, during use, the reciprocating movement of the piston in the connecting rod 109 causes the connecting rod 109 to oscillate. The connecting rod 109 then converts this oscillation into rotational motion of the left sector crank 106 and the right sector crank 107, driving the left main journal 101 and the right main journal 102 to rotate. During this process, lubricating oil enters through the lubrication assembly and lubricates the needle roller bearing 111 and the connecting rod 109. Furthermore, the sector-shaped joints of the left sector crank 106 and the right sector crank 107... The structure's configuration results in an asymmetrical mass distribution, with its protruding fan-shaped corner forming a counterweight. This allows the centrifugal force generated during rotation to efficiently balance the rotational inertial force generated by the crank pin 108 and the connecting rod 109, and partially offset the reciprocating inertial force of the piston assembly. This significantly reduces engine vibration and noise at the source. Furthermore, the outer circumference protrusion 110 on the connecting rod 109 significantly increases the cross-sectional modulus and longitudinal bending stability of the connecting rod 109 when subjected to maximum compressive force (combustion detonation pressure).

[0026] The above-disclosed embodiments are merely one or more preferred embodiments of this application and should not be construed as limiting the scope of this application. Those skilled in the art can understand that all or part of the processes for implementing the above embodiments and equivalent changes made in accordance with the claims of this application still fall within the scope of this application.

Claims

1. A motorcycle crankshaft, comprising a left main journal and a right main journal, wherein a rolling bearing is provided on the left main journal and a keyway is provided on the right main journal, characterized in that, It also includes the crankshaft assembly; The crankshaft assembly includes a left sector crank, a right sector crank, a crank pin, a connecting rod, an outer circular protrusion, and a lubrication assembly. The left sector crank is integrally formed with the left main journal. The rolling bearing is located near the left sector crank. The right sector crank is integrally formed with the right main journal. The crank pin is fixedly installed between the left and right sector cranks. The connecting rod is rotatably engaged with the crank pin via a needle roller bearing. The outer circular protrusion is located on the outside of the connecting rod. The lubrication assembly provides a lubrication channel.

2. The motorcycle crankshaft as described in claim 1, characterized in that, The lubrication assembly includes a main oil passage, a connecting oil passage, and a lubricating oil passage. The main oil passage is located inside the right main journal. The connecting oil passage is located inside the right main journal and communicates with the connecting oil passage. The lubricating oil passage is located inside the crank pin and communicates with the connecting oil passage.

3. The motorcycle crankshaft as described in claim 1, characterized in that, The keyway is also provided with a positioning hole, which extends to the inside of the right spindle journal.

4. The motorcycle crankshaft as described in claim 1, characterized in that, The right spindle journal is also provided with an annular groove, which is located on the side of the right spindle journal near the keyway.

5. The motorcycle crankshaft as described in claim 1, characterized in that, The left main journal is also provided with a timing sprocket, which is located on the side of the left main journal close to the rolling bearing.

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