An oil return structure for a motorcycle engine cylinder head

Abstract

The present invention provides an oil return structure for a motorcycle engine cylinder head, belonging to the technical field of motorcycle engines. It solves the problem of slow oil return speed of lubricating oil in the existing cylinder head. This engine includes a box body, a crankshaft assembly installed in the box body, and an oil pan fixedly connected to the bottom of the box body. The cylinder head is fixedly connected to the top of the box body. The oil return structure includes an oil return channel obliquely arranged downward in the cylinder head. The oil outlet of the oil return channel penetrates through the inner wall of the box body. The oil return structure further includes an arc-shaped oil guiding wall in the box wall of the box body. The oil guiding wall protrudes towards the crankshaft assembly. The top of the oil guiding wall is directly below the oil outlet of the oil return channel, and the bottom is above the oil storage cavity of the oil pan. This oil return structure has the advantages of fast oil return speed of lubricating oil in the cylinder head, small external space occupied by the bottom of the engine, and improved lubrication effect of the crankshaft assembly.

Description

Technical Field

[0001] The present invention belongs to the technical field of motorcycle engines and relates to an oil return structure for a cylinder head of a motorcycle engine. Background Art

[0002] An engine is a machine that can convert other forms of energy into mechanical energy. As the power device of a motorcycle when it is running, when the engine is working, lubricating oil is needed to lubricate and cool various components inside the engine, such as lubricating and cooling the components in the inner cavity of the cylinder head.

[0003] After the lubricating oil enters the inner cavity of the cylinder head, it is necessary to transport the lubricating oil back to the oil pan of the engine to form a cycle. For the existing cycle structure, for example, Chinese patent literature discloses an engine and a vehicle with an oil return passage [Application No.: 202121368146.3; Authorization Publication No.: CN215057645U]. The engine with an oil return passage includes an oil pan, and the oil pan forms an oil storage cavity for storing engine oil; a cylinder head, the cylinder head forms a receiving cavity, and the cylinder head is provided with a first oil return passage; a first end of the first oil return passage communicates with the receiving cavity; a cylinder block, the cylinder block is provided with a second oil return passage; a first end of the second oil return passage communicates with a second end of the first oil return passage; a crankcase, the crankcase is provided with a third oil return passage, a first end of the third oil return passage communicates with a second end of the second oil return passage, and a second end of the third oil return passage communicates with the oil storage cavity.

[0004] For the oil return passage of this structure, the lubricating oil in the receiving cavity flows back to the oil storage cavity of the oil pan through the first oil return passage, the second oil return passage, and the third oil return passage. However, for the oil return passage of this structure, the third oil return passage is located in the wall of the crankcase, and the bottom of the third oil return passage extends into the lubricating oil in the oil pan through a conduit. The flow cross-sectional area of the third oil return passage is small, and the resistance during flow is large, resulting in a slow flow rate and a small flow volume of the lubricating oil when the third oil return passage returns the lubricating oil, reducing the return speed of lubrication. Moreover, the side wall of the crankcase is arranged vertically downward, and the bottom of the oil pan is fixedly connected to the bottom of the crankcase, resulting in a relatively large bottom of the crankcase and the oil pan, occupying a relatively large external installation space. Summary of the Invention

[0005] The purpose of the present invention is to address the above problems existing in the prior art, and propose an oil return structure for a cylinder head of a motorcycle engine, and the technical problem to be solved is how to improve the oil return speed of the lubricating oil in the cylinder head, make the external space occupied by the bottom of the engine small, and at the same time improve the lubrication effect of the crankshaft assembly.

[0006] The object of the present invention can be achieved by the following technical solutions: An oil return structure for a motorcycle engine cylinder head. The engine includes a crankcase, a crankshaft assembly installed in the crankcase, and an oil pan fixedly connected to the bottom of the crankcase. The cylinder head is fixedly connected to the top of the crankcase. The oil return structure includes an oil return passage obliquely downwardly provided in the cylinder head. It is characterized in that the oil outlet of the oil return passage penetrates through the inner wall of the crankcase. The oil return structure further includes an arc-shaped oil guiding wall in the crankcase wall. The oil guiding wall protrudes towards the crankshaft assembly. The top of the oil guiding wall is directly below the oil outlet of the oil return passage, and the bottom is above the oil storage cavity of the oil pan.

[0007] During operation, the lubricating oil in the inner cavity of the cylinder head flows through the oil return passage and the oil outlet into the inner cavity of the crankcase. Subsequently, the lubricating oil quickly flows back into the oil storage cavity of the oil pan along the oil guiding wall. The resistance of the lubricating oil in the crankcase is small, and the flow cross-sectional area is large, which improves the oil return speed of the lubricating oil in the cylinder head. The arc-shaped oil guiding wall is a part of the crankcase wall. The oil guiding wall protrudes towards the crankshaft assembly, which is equivalent to the inner concave setting at the bottom of the crankcase, leaving a clearance space compared with the prior art at the bottom of the crankcase, reducing the external space occupied by the bottom of the crankcase, and being beneficial to the installation of the engine. The lubricating oil flowing out from the oil outlet impacts on the oil guiding wall under the action of inertia and gravity. Some of the lubricating oil will splash up and generate an oil mist. Since the oil guiding wall is arc-shaped and protrudes towards the crankshaft assembly, the position of the oil guiding wall is relatively close to the crankshaft assembly, and the oil droplets and oil mist will splash onto the crankshaft assembly, thereby improving the lubrication effect of the crankshaft assembly.

[0008] In the above-mentioned oil return structure for a motorcycle engine cylinder head, a strip-shaped partition is provided in the crankcase wall of the crankcase. The partition is fixedly connected to the edge of the top of the oil guiding wall. The partition makes a set distance between the top of the oil guiding wall and the oil outlet of the oil return passage. The partition separates the oil outlet from the oil guiding wall, so that the lubricating oil will flow out a certain distance before falling on the oil guiding wall after flowing out from the oil outlet, enabling the lubricating oil to better impact the oil guiding wall, generating a greater impact force, splashing more oil droplets, generating more oil mist, making more oil droplets and oil mist splash onto the crankshaft assembly, improving the lubrication effect of the crankshaft assembly; at the same time, it also prevents the lubricating oil on the oil guiding wall from flowing back to the oil outlet, ensuring the flow rate of the lubricating oil in the oil return passage and improving the oil return speed of the lubricating oil in the cylinder head.

[0009] In the above-mentioned oil return structure of a motorcycle engine cylinder head, a reinforcing ring is formed by the downward protrusion of the inner wall of the box body at the circumferential edge of the oil outlet of the oil return passage. The reinforcing ring is directly above the top of the oil guiding wall, and there is a set spacing between the reinforcing ring and the top of the oil guiding wall. The setting of the oil return port will reduce the strength of the box body at this place. The setting of the reinforcing ring can make up for the lost strength. At the same time, the setting of the reinforcing ring enables the lubricating oil to rush out of the oil outlet without being disturbed, ensuring the impact force of the lubricating oil on the oil guiding wall, and more oil droplets can be splashed, generating more oil mist.

[0010] In the above-mentioned oil return structure of a motorcycle engine cylinder head, the oil return passage is inclined obliquely downward along the direction of the cylinder head towards the crankshaft assembly, and there is an avoidance cavity between the oil outlet of the oil return passage and the side wall of the reinforcing ring close to the crankshaft assembly. The setting of the avoidance cavity enables the lubricating oil rushing out of the oil outlet not to be scattered, ensuring the impact force of the lubricating oil on the oil guiding wall, and more oil droplets can be splashed, generating more oil mist.

[0011] In the above-mentioned oil return structure of a motorcycle engine cylinder head, the oil return structure further includes an oil passing wall arranged vertically in the box wall of the box body. The top of the oil passing wall is connected to the bottom of the oil guiding wall, and the bottom of the oil passing wall is connected to the oil pan. The oil passing wall plays a role in the transitional oil return. At the same time, the oil guiding wall is not directly connected to the oil pan, enabling the bending degree of the oil guiding wall to be larger, making the oil guiding wall closer to the crankshaft assembly, and more oil droplets and oil mist can be splashed onto the crankshaft assembly, improving the lubrication effect of the crankshaft assembly.

[0012] In the above-mentioned oil return structure of a motorcycle engine cylinder head, several first reinforcing ribs are convexly arranged on the inner side wall of the oil guiding wall. All the first reinforcing ribs are arranged along the arc direction of the oil guiding wall, and all the first reinforcing ribs are parallel to each other and arranged at intervals. The setting of the first reinforcing ribs improves the strength of the box body at this place, so that the inward convex setting of the oil guiding wall will not affect the overall strength of the box body. At the same time, the first reinforcing ribs play a role in guiding the flow, enabling the lubricating oil to flow towards the oil pan in a set direction and improving the oil return speed of the lubricating oil.

[0013] In the above-mentioned oil return structure of a motorcycle engine cylinder head, several second reinforcing ribs are convexly arranged on the outer side wall of the oil guiding wall. All the second reinforcing ribs are arranged along the arc direction of the oil guiding wall, and all the second reinforcing ribs are parallel to each other and arranged at intervals. The setting of the second reinforcing ribs improves the strength of the box body at this place, so that the inward convex setting of the oil guiding wall will not affect the overall strength of the box body.

[0014] In the above-mentioned oil return structure of a motorcycle engine cylinder head, the first reinforcing ribs are arranged at equal intervals, the second reinforcing ribs are arranged at equal intervals, and the distance between two adjacent first reinforcing ribs is greater than the distance between two adjacent second reinforcing ribs. The strength of the box at the oil guide wall is ensured so that the inner convex setting of the oil guide wall does not affect the overall strength of the box, and at the same time, the first reinforcing ribs can play a better drainage role and increase the return speed of the lubricating oil.

[0015] In the above-mentioned oil return structure of the cylinder head of a motorcycle engine, the oil pan is located on the left side of the cylinder head in the horizontal direction, and the oil pan and the cylinder head are staggered. This structure leaves a large enough space on the right side of the bottom of the box, so that the external space occupied by the bottom of the engine is small, making it easy to install the engine.

[0016] In the above-mentioned oil return structure of a motorcycle engine cylinder head, the box body includes an upper box body and a lower box body, the oil guide wall is located in the lower box body, the top of the lower box body has a pair of fixed arms protruding outward, and the oil guide wall is located between the pair of fixed arms. The fixed arms enable the engine to be fixedly connected to the frame of the motorcycle, and the setting of the fixed arms ensures that the oil guide wall bulges inward and does not affect the installation of the engine.

[0017] Compared with the prior art, the oil return structure of a motorcycle engine cylinder head provided by the present invention has the following advantages:

[0018] 1. The lubricating oil in the oil return channel of the oil return structure directly rushes from the oil outlet to the inner cavity of the box body, and the lubricating oil quickly flows back to the oil storage cavity of the oil pan along the oil guide wall and the oil passing wall. The resistance encountered by the lubricating oil in the box body is small, and the flow cross-sectional area is large, which improves the oil return speed of the lubricating oil in the cylinder head.

[0019] 2. The oil guide wall of the oil return structure is arc-shaped and protrudes toward the crankshaft assembly, which is equivalent to the concave setting of the bottom of the box. Compared with the prior art, a evacuation space is left at the bottom of the box, which makes the external space occupied by the bottom of the box small, which is conducive to the installation of the engine.

[0020] 3. In this oil return structure, the lubricating oil flows out from the oil outlet and impacts the oil guide wall under the action of inertia and gravity. Part of the lubricating oil will splash and produce oil mist. Since the oil guide wall is arc-shaped and protrudes toward the crankshaft assembly, the position of the oil guide wall and the crankshaft assembly is relatively close, oil droplets and oil mist will splash onto the crankshaft assembly, thereby improving the lubrication effect of the crankshaft assembly. BRIEF DESCRIPTION OF THE DRAWINGS

[0021] Figure 1 It is the overall structural diagram of this oil return structure.

[0022] Figure 2 It is a schematic diagram of the overall structure of the motorcycle engine.

[0023] Figure 3 It is a schematic structural view of the oil guiding wall of this oil return structure.

[0024] Figure 4 It is a schematic structural view of the oil outlet and the reinforcing ring of this oil return structure.

[0025] In the figure, 1 is the box body; 101 is the upper box body; 102 is the lower box body; 103 is the fixed arm; 2 is the crankshaft assembly; 3 is the oil pan; 31 is the oil storage cavity; 4 is the cylinder head; 5 is the oil return passage; 51 is the oil outlet; 6 is the oil guiding wall; 7 is the partition strip; 8 is the reinforcing ring; 9 is the avoidance cavity; 10 is the oil passing wall; 11 is the first reinforcing rib; 12 is the second reinforcing rib. Detailed implementation manners

[0026] The following are specific embodiments of the present invention and in combination with the accompanying drawings, the technical solutions of the present invention will be further described, but the present invention is not limited to these embodiments.

[0027] As Figure 1 , Figure 2 shown, the engine includes a box body 1, a crankshaft assembly 2, an oil pan 3, a cylinder head 4 and an oil return structure. The crankshaft assembly 2 is installed in the box body 1. The box body 1 includes an upper box body 101 and a lower box body 102. The oil pan 3 is fixedly connected to the bottom of the lower box body 102. The cylinder head 4 is fixedly connected to the top of the upper box body 101. The oil pan 3 is horizontally located on the left side of the cylinder head 4. The oil pan 3 and the cylinder head 4 are arranged staggeredly. The oil return structure includes an oil return passage 5, an oil guiding wall 6 and an oil passing wall 10. The oil guiding wall 6 is located in the lower box body 102. The top of the lower box body 102 has a pair of fixedly arranged outwardly protruding fixed arms 103. The oil guiding wall 6 is located between the pair of fixed arms 103.

[0028] The oil return passage 5 is obliquely downwardly inclined in the direction of the cylinder head 4 towards the crankshaft assembly 2. The oil outlet 51 of the oil return passage 5 penetrates through the inner wall of the box body 1. As Figure 4 shown, the inner wall of the box body 1 at the circumferential edge of the oil outlet 51 of the oil return passage 5 bulges downward to form a reinforcing ring 8. There is an avoidance cavity 9 between the oil outlet 51 of the oil return passage 5 and the side wall of the reinforcing ring 8 close to the crankshaft assembly 2.

[0029] As Figure 3 shown, both the oil guiding wall 6 and the oil passing wall 10 are part of the box wall of the box body 1. The oil guiding wall 6 is arc-shaped and protrudes towards the crankshaft assembly 2. The oil passing wall 10 is arranged vertically. The top of the oil passing wall 10 is connected to the bottom of the oil guiding wall 6. The bottom of the oil passing wall 10 is connected to the oil pan 3. The oil passing wall 10 is located above the oil storage cavity 31 of the oil pan 3.

[0030] The box wall of the box body 1 has a strip-shaped partition bar 7, and the partition bar 7 is fixedly connected to the edge at the top of the oil guiding wall 6. The partition bar 7 makes a set distance between the top of the oil guiding wall 6 and the oil outlet 51 of the oil return channel 5. The top of the oil guiding wall 6 is directly below the oil outlet 51 of the oil return channel 5. The reinforcing ring 8 is directly above the top of the oil guiding wall 6, and there is a set distance between the reinforcing ring 8 and the top of the oil guiding wall 6.

[0031] In this embodiment, there are four convex first reinforcing ribs 11 on the inner side wall of the oil guiding wall 6. All the first reinforcing ribs 11 are arranged along the arc direction of the oil guiding wall 6. All the first reinforcing ribs 11 are parallel to each other and arranged at equal intervals. There are seven convex second reinforcing ribs 12 on the outer side wall of the oil guiding wall 6. All the second reinforcing ribs 12 are arranged along the arc direction of the oil guiding wall 6. All the second reinforcing ribs 12 are parallel to each other and arranged at equal intervals. The distance between two adjacent first reinforcing ribs 11 is greater than the distance between two adjacent second reinforcing ribs 12. In actual production, the number of the first reinforcing ribs 11 can be three or five, and the number of the second reinforcing ribs 12 can be six or eight.

[0032] During operation, the lubricating oil in the inner cavity of the cylinder head 4 flows through the oil return channel 5 and the oil outlet 51 into the inner cavity of the box body 1. The lubricating oil jets out in the air for a certain distance and then impacts the oil guiding wall 6. The splashed oil droplets and oil mist lubricate the crankshaft assembly 2. Subsequently, the lubricating oil flows back to the oil storage cavity 31 of the oil pan 3 along the oil guiding wall 6 and the oil passing wall 10. Then, under the action of the oil pump, the lubricating oil in the oil storage cavity 31 is transported into the inner cavity of the cylinder head 4 to form a lubricating oil circulation.

[0033] The specific embodiments described herein are merely illustrative of the spirit of the present invention. Those skilled in the art to which the present invention pertains can make various modifications or supplements to the described specific embodiments or use similar ways to replace them, but will not deviate from the spirit of the present invention or exceed the scope defined by the appended claims.

[0034] Although terms such as box body 1, upper box body 101, lower box body 102, fixed arm 103, crankshaft assembly 2, oil pan 3, oil storage cavity 31, cylinder head 4, oil return channel 5, oil outlet 51, oil guiding wall 6, partition bar 7, reinforcing ring 8, avoidance cavity 9, oil passing wall 10, first reinforcing rib 11, second reinforcing rib 12, etc. are used more in this article, the possibility of using other terms is not excluded. The use of these terms is only to more conveniently describe and explain the essence of the present invention; interpreting them as any additional limitation is contrary to the spirit of the present invention.

Claims

1. An oil return structure for a motorcycle engine cylinder head. The engine includes a crankcase (1), a crankshaft assembly (2) installed in the crankcase (1), and an oil pan (3) fixedly connected to the bottom of the crankcase (1). The cylinder head (4) is fixedly connected to the top of the crankcase (1). The oil return structure includes an oil return passage (5) obliquely downwardly provided in the cylinder head (4), and is characterized in that, The oil outlet (51) of the oil return passage (5) penetrates the inner wall of the box body (1), and the oil return structure further comprises an arc-shaped oil guide wall (6) in the box wall of the box body (1), the oil guide wall (6) is arranged to protrude toward the crankshaft assembly (2), the top of the oil guide wall (6) is located directly below the oil outlet (51) of the oil return passage (5), and the bottom is located above the oil storage chamber (31) of the oil pan (3), and the box wall of the box body (1) has a long strip-shaped partition ( 7), the spacer (7) is fixedly connected to the edge of the top of the oil guide wall (6), and the spacer (7) allows a set distance between the top of the oil guide wall (6) and the oil outlet (51) of the oil return channel (5). The lubricating oil in the inner cavity of the cylinder head (4) flows to the inner cavity of the casing (1) through the oil return channel (5) and the oil outlet (51). The lubricating oil is suspended in the air for a distance and then impacts the oil guide wall (6), and the splashed oil droplets and oil mist lubricate the crankshaft assembly (2).

2. The oil return structure of a motorcycle engine cylinder head according to claim 1, characterized in that, The inner wall of the box body (1) at the circumferential edge of the oil outlet (51) of the oil return channel (5) protrudes downward to form a reinforcement ring (8), and the reinforcement ring (8) is located directly above the top of the oil guide wall (6), and there is a set distance between the reinforcement ring (8) and the top of the oil guide wall (6).

3. The oil return structure of a motorcycle engine cylinder head according to claim 2, characterized in that, The oil return channel (5) is arranged obliquely downward in a direction from the cylinder head (4) toward the crankshaft assembly (2), and an avoidance cavity (9) is provided between the oil outlet (51) of the oil return channel (5) and the side wall of the reinforcement ring (8) close to the crankshaft assembly (2).

4. The oil return structure of a motorcycle engine cylinder head according to claim 1 or 2 or 3, characterized in that, The oil return structure also includes an oil-passing wall (10) arranged in the vertical direction in the box wall of the box body (1), the top of the oil-passing wall (10) is connected to the bottom of the oil guide wall (6), and the bottom of the oil-passing wall (10) is connected to the oil pan (3).

5. The oil return structure of a motorcycle engine cylinder head according to claim 1 or 2 or 3, characterized in that, The inner side wall of the oil guide wall (6) is provided with a plurality of protruding first reinforcing ribs (11), all of the first reinforcing ribs (11) are arranged along the arc direction of the oil guide wall (6), and all of the first reinforcing ribs (11) are mutually parallel and spaced apart.

6. The oil return structure of a motorcycle engine cylinder head according to claim 5, characterized in that, The outer side wall of the oil guide wall (6) is provided with a plurality of protruding second reinforcing ribs (12), all of the second reinforcing ribs (12) are arranged along the arc direction of the oil guide wall (6), and all of the second reinforcing ribs (12) are mutually parallel and spaced apart.

7. The oil return structure of a motorcycle engine cylinder head according to claim 6, characterized in that, The first reinforcing ribs (11) are arranged at equal intervals, the second reinforcing ribs (12) are arranged at equal intervals, and the distance between two adjacent first reinforcing ribs (11) is greater than the distance between two adjacent second reinforcing ribs (12).

8. The oil return structure of a motorcycle engine cylinder head according to claim 1 or 2 or 3, characterized in that, The oil pan (3) is located on the left side of the cylinder head (4) in the horizontal direction, and the oil pan (3) and the cylinder head (4) are staggered.

9. The oil return structure of a motorcycle engine cylinder head according to claim 1 or 2 or 3, characterized in that, The box body (1) comprises an upper box body (101) and a lower box body (102); the oil guide wall (6) is located in the lower box body (102); the top of the lower box body (102) has a pair of fixed arms (103) protruding outwards; the oil guide wall (6) is located between the pair of fixed arms (103).

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