Piston cooling structure of motorcycle engine

Abstract

The utility model belongs to the technical field of motorcycle engines, and relates to a piston cooling structure of a motorcycle engine, which comprises a crankcase, a crankshaft assembly and an air cylinder body, the crankcase comprises an outer ring body with a joint surface and an inner ring body with a crankshaft hole, and cooling oil ducts are arranged in the crankcase and the air cylinder body. The air cylinder body is installed on one side of the crankcase and extends into the crankcase, a piston connected with the crankshaft assembly is arranged in the air cylinder body in a sliding mode, a piston cooling oil outlet hole communicated with the cooling oil channel is formed in the position, close to the air cylinder body, of the inner ring body, and a spray pipe communicated with the piston cooling oil outlet hole is fixed to the inner ring body. The spraying pipe is of an L-shaped or arc-shaped structure, and the oil spraying end of the spraying pipe extends into the air cylinder body and faces the back of the piston. The piston cooling structure of the motorcycle engine has the advantages of being simple in structure and good in cooling effect.

Description

Technical Field

[0001] This utility model belongs to the technical field of motorcycle engines and relates to a piston cooling structure for a motorcycle engine. Background Technology

[0002] A motorcycle engine consists of a cylinder block, pistons housed within the cylinder block, a crankshaft and connecting rod assembly, and a crankcase. The piston converts the energy from fuel combustion into rotational motion of the crankshaft and connecting rods, which is then transmitted to the external wheel via a connecting mechanism, causing the wheel to rotate. Due to the reciprocating motion of the piston, the friction between it and the cylinder, as well as the heat from combustion in the engine's combustion chamber, result in a high load and temperature on the piston. If the piston is not adequately cooled, it can easily lead to piston deformation or even dangerous situations such as cylinder scoring.

[0003] Chinese invention patent application CN109723531A (publication date 2019.05.07) discloses a piston cooling oil circuit system for a motorcycle engine, including a crankcase body, a crankshaft connecting rod assembly, a cylinder, a piston, and left and right crankcase covers. The left and right crankcase covers and the crankcase body cooperate to form the crankcase body. The crankshaft connecting rod assembly is provided inside the crankcase body. A cooling oil circuit is provided at the mating surface between the crankcase body and the right crankcase cover. A hollow cylinder is provided below the cylinder of the crankcase body. One end of the hollow cylinder is closed, and the other end is connected to the cooling oil circuit to form a piston cooling oil circuit. The oil injection port of the piston cooling oil circuit is provided on the cylinder with one or more spray holes. The cooling oil circuit is connected to an oil pump, so that cooling oil is sprayed onto the piston to cool the piston and the crankshaft connecting rod assembly below.

[0004] The aforementioned motorcycle engine piston cooling oil circuit system is relatively simple, but its hollow cylinder is far from the piston, requiring a large pressure during fuel injection, and the cooling effect is not good. Utility Model Content

[0005] This invention addresses the shortcomings of existing technologies by providing a piston cooling structure for a motorcycle engine, which has the advantages of simple structure and good cooling effect.

[0006] To solve the above-mentioned technical problems, the objective of this utility model is achieved through the following technical solution:

[0007] A piston cooling structure for a motorcycle engine includes a crankcase, a crankshaft assembly, and a cylinder block. The crankcase includes an outer ring with a mating surface and an inner ring with a crankshaft bore. Cooling oil passages are provided in the crankcase and cylinder block. The cylinder block is mounted on one side of the crankcase and extends into the crankcase. A piston connected to the crankshaft assembly is slidably disposed in the cylinder block. A piston cooling oil outlet communicating with the cooling oil passages is provided on the inner ring near the cylinder block. A nozzle communicating with the piston cooling oil outlet is fixed on the inner ring. The nozzle has an L-shaped or arc-shaped structure, and its oil injection end extends into the cylinder block and faces the back of the piston.

[0008] In the piston cooling structure of the motorcycle engine described above, preferably, the nozzle includes a connecting section distributed radially along the cylinder block and a nozzle section distributed axially along the cylinder block.

[0009] In the piston cooling structure of the motorcycle engine described above, a cylinder liner is provided in the cylinder body, the piston is slidably disposed in the cylinder liner, an end notch is provided on the side of the cylinder liner near the inner ring, and the nozzle extends from the end notch into the corresponding area inside the cylinder liner.

[0010] In the piston cooling structure of the motorcycle engine described above, preferably, when the piston is located near the end of its stroke close to the crankcase, the oil injection end of the nozzle is located inside the piston.

[0011] In the piston cooling structure of a motorcycle engine described above, the nozzle is connected to one side of the mounting plate and penetrates the mounting plate. Fasteners are provided on the other side of the mounting plate. The mounting plate is fastened to the inner ring body by the fasteners. The nozzle is simultaneously inserted into the piston cooling oil outlet hole. Preferably, the nozzle is welded to the mounting plate or integrally formed.

[0012] In the piston cooling structure of the motorcycle engine described above, the inner ring body is provided with a mounting groove that mates with a mounting plate, one side of the mounting groove is provided with a threaded hole that mates with a fastener, and the piston cooling oil outlet is provided on the other side of the mounting groove.

[0013] In the piston cooling structure of the motorcycle engine described above, a sealing groove is provided in the mounting groove to surround the piston cooling oil outlet hole, a sealing ring is fitted on the insertion end of the nozzle, and the sealing ring is pressed tightly after the mounting plate is fixed, and the sealing ring and the sealing groove form a sealing structure.

[0014] In the piston cooling structure of the above-mentioned motorcycle engine, a cylinder block cooling oil passage is provided in the cylinder body, and a crankcase cooling oil passage is provided on the mating surface of the crankcase and inside the crankcase. The piston cooling oil outlet is connected to the cylinder block cooling oil passage or the crankcase cooling oil passage. The cooling oil is driven to circulate by an oil pump, which is driven by the crankshaft assembly.

[0015] In the piston cooling structure of the motorcycle engine described above, preferably, the crankcase is provided with a piston cooling oil delivery passage and a cylinder block cooling oil delivery passage. The crankcase cooling oil passage is connected to the cylinder block cooling oil passage through the cylinder block cooling oil delivery passage, and the cylinder block cooling oil passage is connected to the piston cooling oil outlet through the piston cooling oil delivery passage.

[0016] Compared with the prior art, this utility model has the following advantages:

[0017] 1. This utility model provides a piston cooling structure for a motorcycle engine. The piston cooling oil outlet is located on the inner ring near the cylinder block, significantly shortening the distance between the oil outlet and the piston. This utility model further improves the nozzle structure by extending the injection tip into the cylinder block and towards the piston's back, further shortening the distance between the injection tip and the piston. Through the inwardly extended injection tip, cooling oil can be directly sprayed onto the piston's back at close range, thereby achieving a better cooling effect.

[0018] 2. This utility model further optimizes the installation structure of the nozzle, making it more secure, more stable, and with better sealing. Attached Figure Description

[0019] Figure 1 This is a perspective view of the present invention;

[0020] Figure 2 yes Figure 1 Enlarged view of point A;

[0021] Figure 3 This is a perspective view of the crankcase of this utility model;

[0022] Figure 4 This is another perspective view of the crankcase of this utility model;

[0023] Figure 5 yes Figure 4 Enlarged view of point B;

[0024] Figure 6 This is a perspective view of the cylinder block of this utility model;

[0025] Figure 7 This is a perspective view of the nozzle of this utility model;

[0026] Reference numerals: 1. Crankcase; 2. Cylinder block; 3. Mating surface; 4. Outer ring; 5. Crankshaft bore; 6. Inner ring; 7. Piston; 8. Piston cooling oil outlet; 9. Nozzle; 10. Cylinder liner; 11. End notch; 12. Mounting plate; 13. Fastener; 14. Mounting groove; 15. Threaded hole; 16. Sealing groove; 17. Sealing ring; 18. Cylinder block cooling oil passage; 19. Crankcase cooling oil passage; 20. Oil pump; 21. Piston cooling oil delivery passage; 22. Cylinder block cooling oil delivery passage. Detailed Implementation

[0027] The present invention will be further described below with reference to the accompanying drawings and specific embodiments. See also: Figure 1-7 :

[0028] A piston cooling structure for a motorcycle engine includes a crankcase 1, a crankshaft assembly, and a cylinder block 2. The crankcase 1 includes an outer ring 4 with a mating surface 3 and an inner ring 6 with a crankshaft bore 5. Cooling oil passages are provided in the crankcase 1 and the cylinder block 2. The cylinder block 2 is mounted on one side of the crankcase 1 and extends into the crankcase 1. A piston 7 connected to the crankshaft assembly is slidably disposed in the cylinder block 2. A piston cooling oil outlet 8 communicating with the cooling oil passages is provided on the inner ring 6 near the cylinder block 2. A nozzle 9 communicating with the piston cooling oil outlet 8 is fixed on the inner ring 6. The nozzle 9 has an L-shaped or arc-shaped structure, and its oil injection end extends into the cylinder block 2 and faces the back of the piston 7.

[0029] The operation of the crankcase 1, crankshaft assembly (including crankshaft, crankshaft connecting rod, etc., not shown in the attached drawings), cylinder block 2, and piston 7 in this embodiment is the same as in the prior art, and will not be described again here. The cooling process in this embodiment is as follows: under the drive of the oil pump 20, the cooling oil circulates in the cooling oil passage to cool the crankcase 1 and cylinder block 2. A portion of the cooling oil in the cooling oil passage enters the nozzle 9 through the piston cooling oil outlet 8, and is sprayed out from the end of the nozzle 9 under pressure. The sprayed cooling oil is directed towards the back of the piston 7, and then splashes to cover a larger area of ​​the piston 7. Finally, the sprayed cooling oil flows back into the crankcase 1 from the back of the piston 7.

[0030] Furthermore, refer to the appendix Figure 2 and attached Figure 6 The cylinder block 2 is provided with a cylinder liner 10, and the piston 7 is slidably disposed within the cylinder liner 10. The cylinder liner 10 has an end notch 11 on the side near the inner ring 6, and the nozzle 9 extends from the end notch 11 into the corresponding area inside the cylinder liner 10. In this embodiment, the nozzle 9 includes a connecting section radially distributed along the cylinder block 2 and a nozzle section axially distributed along the cylinder block 2. The end notch 11 is used to avoid the connecting section of the nozzle 9, allowing the nozzle 9 to be closer to the piston 7.

[0031] To further improve the cooling effect, preferably, when the piston 7 is located near the end of its stroke near the crankcase 1, the oil injection end of the nozzle 9 is located inside the piston 7.

[0032] Comparison Appendix Figure 4 , attached Figure 5 and attached Figure 7 In this embodiment, the installation structure of the nozzle 9 is further optimized. Specifically, the nozzle 9 is connected to one side of the mounting plate 12 and passes through the mounting plate 12. The other side of the mounting plate 12 is provided with a fastener 13. The mounting plate 12 is fastened to the inner ring body 6 through the fastener 13. The nozzle 9 is also inserted into the piston cooling oil outlet hole 8. Preferably, the nozzle 9 is welded to the mounting plate 12 or integrally formed.

[0033] Furthermore, the inner ring body 6 is provided with a mounting groove 14 that mates with the mounting plate 12, and a threaded hole 15 that mates with the fastener 13 is provided on one side of the mounting groove 14. The piston cooling oil outlet hole 8 is provided on the other side of the mounting groove 14.

[0034] To improve sealing, a sealing groove 16 is provided in the mounting groove 14 to surround the piston cooling oil outlet hole 8. A sealing ring 17 is fitted on the insertion end of the nozzle 9. After the mounting plate 12 is fixed, the sealing ring 17 is pressed tightly. The sealing ring 17 and the sealing groove 16 form a sealing structure.

[0035] Comparison Appendix Figure 4 and attached Figure 6 The specific oil circuit structure of this embodiment is as follows: a cylinder block cooling oil passage 18 is provided inside the cylinder block 2, and a crankcase cooling oil passage 19 is provided inside the crankcase 1 and on the mating surface 3. The piston cooling oil outlet 8 is connected to the cylinder block cooling oil passage 18 or the crankcase cooling oil passage 19. The cooling oil is driven to circulate by an oil pump 20, which is driven by the crankshaft assembly. When the crankshaft assembly rotates, it drives the oil pump 20 to work through gears. The oil pump 20 drives the cooling oil to circulate in the crankcase cooling oil passage 19 and the cylinder block cooling oil passage 18 to cool the corresponding parts. A portion of the cooling oil in the crankcase cooling oil passage 19 or the cylinder block cooling oil passage 18 is sprayed out from the nozzle 9 under pressure to cool the piston 7.

[0036] In this embodiment, preferably, the crankcase 1 is provided with a piston cooling oil delivery passage 21 and a cylinder block cooling oil delivery passage 22. The crankcase cooling oil passage 19 is connected to the cylinder block cooling oil passage 18 through the cylinder block cooling oil delivery passage 22, and the cylinder block cooling oil passage 18 is connected to the piston cooling oil outlet 8 through the piston cooling oil delivery passage 21. The oil pump 20 first pumps cooling oil into the crankcase cooling oil passage 19, then a portion enters each branch of the crankcase cooling oil passage 19 to cool the crankcase 1, and another portion enters the cylinder block cooling oil passage 18 through the cylinder block cooling oil delivery passage 22 to cool the cylinder block 2. A portion of the cooling oil in the cylinder block cooling oil passage 18 then enters the nozzle 9 through the piston cooling oil delivery passage 21 and the piston cooling oil outlet 8 to cool the piston 7.

[0037] The above embodiments are merely preferred embodiments of the present utility model and are not intended to limit the scope of protection of the present utility model. Therefore, all equivalent changes made to the structure, shape, and principle of the present utility model should be covered within the scope of protection of the present utility model.

Claims

1. A piston cooling structure for a motorcycle engine, comprising a crankcase (1), a crankshaft assembly, and a cylinder block (2), wherein the crankcase (1) comprises an outer ring (4) having a mating surface (3) and an inner ring (6) having a crankshaft bore (5), cooling oil passages are provided in the crankcase (1) and the cylinder block (2), the cylinder block (2) is mounted on one side of the crankcase (1) and extends into the crankcase (1), and a piston (7) connected to the crankshaft assembly is slidably disposed in the cylinder block (2), characterized in that, The inner ring (6) is provided with a piston cooling oil outlet hole (8) that communicates with the cooling oil passage near the cylinder body (2). The inner ring (6) is fixed with a nozzle (9) that communicates with the piston cooling oil outlet hole (8). The nozzle (9) has an L-shaped or arc-shaped structure, and its oil injection end extends into the cylinder body (2) and faces the back of the piston (7).

2. The piston cooling structure for a motorcycle engine according to claim 1, characterized in that, The cylinder block (2) is provided with a cylinder liner (10), the piston (7) is slidably disposed in the cylinder liner (10), the cylinder liner (10) is provided with an end notch (11) on the side near the inner ring body (6), and the nozzle (9) extends from the end notch (11) into the corresponding area inside the cylinder liner (10).

3. The piston cooling structure for a motorcycle engine according to claim 1, characterized in that, When the piston (7) is located at the end of its stroke near the crankcase (1), the oil injection end of the nozzle (9) is located inside the piston (7).

4. The piston cooling structure for a motorcycle engine according to claim 1, characterized in that, The nozzle (9) is connected to one side of the mounting plate (12) and passes through the mounting plate (12). Fasteners (13) are provided on the other side of the mounting plate (12). The mounting plate (12) is fastened to the inner ring body (6) by the fasteners (13). The nozzle (9) is also inserted into the piston cooling oil outlet hole (8).

5. The piston cooling structure for a motorcycle engine according to claim 4, characterized in that, The inner ring (6) is provided with a mounting groove (14) that mates with the mounting plate (12). One side of the mounting groove (14) is provided with a threaded hole (15) that mates with a fastener (13). The piston cooling oil outlet (8) is provided on the other side of the mounting groove (14).

6. The piston cooling structure for a motorcycle engine according to claim 5, characterized in that, The mounting groove (14) is provided with a sealing groove (16) surrounding the piston cooling oil outlet (8). The insertion end of the nozzle (9) is fitted with a sealing ring (17). After the mounting plate (12) is fixed, the sealing ring (17) is pressed tightly. The sealing ring (17) and the sealing groove (16) form a sealing structure.

7. The piston cooling structure for a motorcycle engine according to claim 1, characterized in that, The cylinder block (2) is provided with a cylinder block cooling oil passage (18), and the crankcase (1) mating surface (3) and the inside of the crankcase (1) are provided with a crankcase cooling oil passage (19). The piston cooling oil outlet (8) is connected to the cylinder block cooling oil passage (18) or the crankcase cooling oil passage (19). The cooling oil is driven to circulate by an oil pump (20), which is driven by the crankshaft assembly.

8. The piston cooling structure for a motorcycle engine according to claim 7, characterized in that, The crankcase (1) is provided with a piston cooling oil passage (21) and a cylinder block cooling oil passage (22). The crankcase cooling oil passage (19) is connected to the cylinder block cooling oil passage (18) through the cylinder block cooling oil passage (22). The cylinder block cooling oil passage (18) is connected to the piston cooling oil outlet (8) through the piston cooling oil passage (21).

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