Cam shaft with small wrap angle

Abstract

The utility model discloses a small wrap angle camshaft which comprises a shaft body, an air inlet cam and an exhaust cam, the air inlet cam and the exhaust cam are both arranged on the shaft body, and the outer contour of the air inlet cam is sequentially provided with an air inlet lift section, a first air inlet wrap angle section, an air inlet opening section, a second air inlet wrap angle section and an air inlet drop section in the circumferential direction of the shaft body. An exhaust lift section, a first exhaust wrap angle section, an exhaust opening section, a second exhaust wrap angle section and an exhaust drop section are sequentially arranged on the outer contour of the exhaust peach in the circumferential direction of the shaft body. The corner amplitudes of the first air inlet wrap angle section, the air inlet opening section and the second air inlet wrap angle section are larger than the corner amplitudes of the first air outlet wrap angle section, the air outlet opening section and the second air outlet wrap angle section. The utility model has the beneficial effects that air can enter the engine more smoothly, and the working efficiency and the fuel oil combustion rate of the engine can be improved. Intake and exhaust cooperation in the engine operation process is optimized, engine performance and heat efficiency are improved, and the combustion consumption rate is reduced.

Description

Technical Field

[0001] This utility model relates to the technical field of camshafts, specifically to a small wrap angle camshaft. Background Technology

[0002] The camshaft controls the opening and closing of the valves. The main body of the camshaft is a cylindrical rod approximately the same length as the cylinder bank. Several cams are mounted on it to drive the valves. The cams have an egg-shaped profile. Its design aims to ensure sufficient intake and exhaust for the cylinders. Furthermore, considering engine durability and smooth operation, the valves cannot experience excessive impact during acceleration and deceleration, otherwise it will cause severe valve wear, increased noise, or other serious consequences.

[0003] Chinese invention patent application CN115405395A discloses a camshaft based on Miller cycle technology and a 280 diesel engine. The camshaft includes a shaft and several cam assemblies mounted on the shaft. Each cam assembly includes an intake cam, an exhaust cam, and a fuel injection cam. The intake cam profile includes an intake base circle and a camshaft connected to the intake base circle. The camshaft includes an intake lift section, an intake leveling section, and an intake drop section. The intake lift section has an angle of 0°–63° and a maximum lift of 15.4 mm; the intake leveling section has an angle of 63°–77° and a maximum lift of 15.4 mm; the intake drop section has an angle of 77°–134°; when the angle is 134°, its lift relative to the intake base circle is 0. The application also discloses a 280 diesel engine based on this camshaft. This engine can close the intake valves earlier, effectively reducing in-cylinder combustion temperature and thus reducing NOx emissions.

[0004] The timing of valve opening and closing plays a crucial role in engine efficiency, and the market is placing new demands on the efficiency and fuel consumption of automobile engines. Utility Model Content

[0005] In order to solve the above-mentioned technical problems, the purpose of this utility model is to provide a small wrap angle camshaft, which includes a shaft body, an intake cam and an exhaust cam, and the small wrap angle camshaft has the advantages of improving engine working efficiency and fuel combustion rate.

[0006] To achieve the above-mentioned objectives, the technical solution adopted by this utility model is as follows:

[0007] A small-angle camshaft includes a shaft body, an intake cam, and an exhaust cam. Both the intake cam and exhaust cam are mounted on the shaft body. The intake cam includes an intake base circle and an intake mandrel. The intake base circle is fixedly connected to the shaft body, and the intake mandrel is fixedly connected to the intake base circle. The outer contour of the intake mandrel, along the circumference of the shaft body, is sequentially provided with an intake lift section, a first intake mandrel section, an intake opening section, a second intake mandrel section, and an intake drop section. The exhaust cam includes an exhaust base circle and an exhaust mandrel. The exhaust base circle is fixedly connected to the shaft body, and the exhaust mandrel is fixedly connected to the exhaust base circle. The outer contour of the exhaust mandrel, along the circumference of the shaft body, is sequentially provided with an exhaust lift section, a first exhaust mandrel section, an exhaust opening section, a second exhaust mandrel section, and an exhaust drop section. The rotation angles of the first intake mandrel section, the intake opening section, and the second intake mandrel section are greater than the rotation angles of the first exhaust mandrel section, the exhaust opening section, and the second exhaust mandrel section.

[0008] This configuration increases the time the intake valve is at its maximum opening, reducing the resistance the intake valve causes to the air entering the engine. This allows air to enter the engine more smoothly, ensuring sufficient oxygen for combustion in the combustion chamber. This, in turn, ensures complete fuel combustion, improving combustion efficiency and ultimately enhancing engine performance and fuel combustion rate.

[0009] Preferably, the two ends of the first intake envelope section smoothly transition to the intake lift section and the intake opening section, respectively, and the two ends of the second intake envelope section smoothly transition to the intake opening section and the intake drop section, respectively.

[0010] This configuration makes the intake valve movement process more stable.

[0011] Preferably, the two ends of the first exhaust wrap-around section smoothly transition to the exhaust lift section and the exhaust opening section, respectively, and the two ends of the second exhaust wrap-around section smoothly transition to the exhaust opening section and the exhaust descent section, respectively.

[0012] This setting makes the exhaust valve movement more stable.

[0013] Preferably, the radius of the arc of the first intake corner segment is greater than the radius of the arc of the second intake corner segment.

[0014] This configuration makes the transition of the intake valve from the intake lift stage to the intake opening stage more stable.

[0015] Preferably, the angle of the intake lift section is 0° to 27.1°, the angle of the first intake wrap-around section is 27.1° to 58.4°, the angle of the intake opening section is 58.4° to 86.3°, the angle of the second intake wrap-around section is 86.3° to 117.6°, the angle of the intake drop section is 117.6° to 144.7°, and the angle of the intake base circle is 144.7° to 360°.

[0016] This setting optimizes the coordination of intake and exhaust during engine operation.

[0017] Preferably, the rotation angle of the exhaust lift section is 0° to 35°, the rotation angle of the first exhaust wrap-around section is 35° to 44.4°, the rotation angle of the exhaust opening section is 44.4° to 75.6°, the rotation angle of the second exhaust wrap-around section is 75.6° to 85°, the rotation angle of the exhaust fall section is 85° to 120°, and the rotation angle of the exhaust base circle is 120° to 360°.

[0018] This setting optimizes the coordination of intake and exhaust during engine operation.

[0019] Preferably, the end of the intake lift section that is away from the first intake envelope section smoothly transitions to the intake base circle, and the end of the intake drop section that is away from the second intake envelope section smoothly transitions to the intake base circle.

[0020] This configuration makes the transition of the intake valve from the intake base circle to the intake lift section more stable.

[0021] Preferably, the end of the exhaust lift section away from the first exhaust wrap-around section smoothly transitions to the exhaust base circle, and the end of the exhaust fall section away from the second exhaust wrap-around section smoothly transitions to the exhaust base circle.

[0022] This configuration makes the transition of the exhaust valve from the exhaust base circle to the exhaust lift section more stable.

[0023] Preferably, multiple intake cams and multiple exhaust cams are provided, and the multiple intake cams and multiple exhaust cams correspond one-to-one.

[0024] This configuration enables the movement of the intake and exhaust valves on different cylinders.

[0025] Preferably, the shaft is fixedly connected to a pulley and a measuring wheel, the intake cam and the exhaust cam are both located between the pulley and the measuring wheel, the measuring wheel is provided with a measuring groove, and the bottom of the measuring groove is provided with an inclined surface.

[0026] This configuration optimizes the camshaft structure layout, making the overall camshaft structure more balanced and its center of gravity closer to the center of the shaft.

[0027] Compared with the prior art, this utility model has achieved beneficial technical effects:

[0028] 1. The turning angles of the first intake envelope section, the intake opening section, and the second intake envelope section are 90.5°, and the turning angles of the first exhaust envelope section, the exhaust opening section, and the second exhaust envelope section are 85°. The turning angles of the first intake envelope section, the intake opening section, and the second intake envelope section are greater than the turning angles of the first exhaust envelope section, the exhaust opening section, and the second exhaust envelope section. This increases the time that the intake valve is at its maximum opening, reduces the resistance of the intake valve to the air entering the engine, and allows air to enter the engine more smoothly. This ensures that there is sufficient oxygen in the engine combustion chamber for combustion, thereby ensuring complete fuel combustion and improving combustion efficiency. This achieves the advantages of improving engine working efficiency and fuel combustion rate.

[0029] 2. By setting the first intake envelope angle, the process of the intake valve transitioning from the intake lift stage to the intake opening stage is more stable. By setting the second intake envelope angle, the process of the intake valve transitioning from the intake opening stage to the intake fall stage is more stable, which can improve the stability of the intake valve movement. Attached Figure Description

[0030] Figure 1 This is a schematic diagram of the structure of a small-angle camshaft according to an embodiment of this utility model;

[0031] Figure 2 This is a schematic diagram of the intake cam in an embodiment of the present invention;

[0032] Figure 3 This is a schematic diagram of the exhaust cam structure in an embodiment of this utility model;

[0033] Figure 4 This is a schematic diagram of the measuring wheel in an embodiment of this utility model.

[0034] The technical features referred to by the various reference numerals in the accompanying drawings are as follows:

[0035] 11. Shaft; 12. Pulley; 13. Measuring wheel; 14. Measuring groove; 15. Inclined surface; 21. Intake camshaft; 22. Intake base circle; 23. Intake cone; 24. Intake lift section; 25. First intake wrap angle section; 26. Intake opening section; 27. Second intake wrap angle section; 28. Intake fall section; 31. Exhaust camshaft; 32. Exhaust base circle; 33. Exhaust cone; 34. Exhaust lift section; 35. First exhaust wrap angle section; 36. Exhaust opening section; 37. Second exhaust wrap angle section; 38. Exhaust fall section. Detailed Implementation

[0036] To make the objectives, technical solutions and advantages of this utility model clearer, the present utility model will be further described in detail below with reference to the embodiments. However, the scope of protection of this utility model is not limited to the specific embodiments described below.

[0037] refer to Figure 1-4 A small-angle camshaft includes a shaft body 11, an intake cam 21, and an exhaust cam 31. Both the intake cam 21 and the exhaust cam 31 are mounted on the shaft body 11. The intake cam 21 includes an intake base circle 22 and an intake cone 23. The intake base circle 22 is fixedly connected to the shaft body 11, and the intake cone 23 is fixedly connected to the intake base circle 22. The outer contour of the intake cone 23, along the circumference of the shaft body 11, is sequentially provided with an intake lift section 24, a first intake wrap-around section 25, an intake opening section 26, a second intake wrap-around section 27, and an intake drop section 28. The exhaust cam... 31 includes an exhaust base circle 32 and an exhaust valve 33. The exhaust base circle 32 is fixedly connected to the shaft 11, and the exhaust valve 33 is fixedly connected to the exhaust base circle 32. The outer contour of the exhaust valve 33 is provided with an exhaust lift section 34, a first exhaust corner section 35, an exhaust opening section 36, a second exhaust corner section 37, and an exhaust drop section 38 sequentially along the circumference of the shaft 11. The rotation angles of the first intake corner section 25, the intake opening section 26, and the second intake corner section 27 are greater than the rotation angles of the first exhaust corner section 35, the exhaust opening section 36, and the second exhaust corner section 37. The arc centers of the intake base circle 22, the exhaust base circle 32, the intake opening section 26, and the exhaust opening section are located on the axis of the shaft 11. The arc radius of the first intake corner section 25 is greater than the arc radius of the second intake corner section 27. This makes the transition of the intake valve from the intake lift section 24 to the intake opening section 26 more stable. There are three intake cams 21 and three exhaust cams 31 in total, with each set corresponding to a different intake cam 21 and exhaust cam 31. These three sets of intake cams 21 and exhaust cams 31 drive the intake and exhaust valves on different cylinders.

[0038] The first intake envelope section 25 smoothly transitions at both ends to the intake lift section 24 and the intake opening section 26, respectively. The second intake envelope section 27 smoothly transitions at both ends to the intake opening section 26 and the intake drop section 28, respectively. This makes the process of the intake valve moving through the intake lift section 24, the first intake envelope section 25, the intake opening section 26, the second intake envelope section 27, and the intake drop section 28 more stable. Similarly, the first exhaust envelope section 35 smoothly transitions at both ends to the exhaust lift section 34 and the exhaust opening section 36, respectively. The second exhaust envelope section 37 smoothly transitions at both ends to the exhaust opening section 36 and the exhaust drop section 38, respectively. This makes the process of the exhaust valve moving through the exhaust lift section 34, the first exhaust envelope section 35, the exhaust opening section 36, the second exhaust envelope section 37, and the exhaust drop section 38 more stable. The end of the intake lift section 24 furthest from the first intake envelope section 25 smoothly transitions to the intake base circle 22, and the end of the intake fall section 28 furthest from the second intake envelope section 27 smoothly transitions to the intake base circle 22. Both the intake lift section 24 and the intake fall section 28 are tangent to the outer contour of the intake base circle 22, making the transition of the intake valve from the intake base circle 22 to the intake lift section 24 more stable. Similarly, the end of the exhaust lift section 34 furthest from the first exhaust envelope section 35 smoothly transitions to the exhaust base circle 32, and the end of the exhaust fall section 38 furthest from the second exhaust envelope section 37 smoothly transitions to the exhaust base circle 32. Both the exhaust lift section 34 and the exhaust fall section 38 are tangent to the outer contour of the exhaust base circle 32, making the transition of the exhaust valve from the exhaust base circle 32 to the exhaust lift section 34 more stable.

[0039] The intake lift section 24 has an angle of 0° to 27.1°, the first intake wrap-around section 25 has an angle of 27.1° to 58.4°, the intake opening section 26 has an angle of 58.4° to 86.3°, the second intake wrap-around section 27 has an angle of 86.3° to 117.6°, the intake drop section 28 has an angle of 117.6° to 144.7°, and the intake base circle 22 has an angle of 144.7° to 360°. This optimizes the coordination of intake and exhaust during engine operation, improving engine performance and thermal efficiency while reducing combustion consumption. The exhaust lift section 34 has a rotation angle of 0° to 35°, the first exhaust wrap-around section 35 has a rotation angle of 35° to 44.4°, the exhaust opening section 36 has a rotation angle of 44.4° to 75.6°, the second exhaust wrap-around section 37 has a rotation angle of 75.6° to 85°, the exhaust fall section 38 has a rotation angle of 85° to 120°, and the exhaust base circle 32 has a rotation angle of 120° to 360°. This optimizes the coordination of intake and exhaust during engine operation, improves engine performance and thermal efficiency, and reduces combustion consumption.

[0040] A pulley 12 and a measuring wheel 13 are fixedly connected to the shaft 11. The intake cam 21 and exhaust cam 31 are both located between the pulley 12 and the measuring wheel 13. The measuring wheel 13 has a measuring groove 14, and the bottom of the measuring groove 14 has an inclined surface 15. The pulley 12 is driven to rotate by a belt mounted on the engine crankshaft, thereby driving the shaft 11 to rotate. The measuring wheel 13 and pulley 12 are respectively located on both sides of the shaft 11, optimizing the camshaft structural layout, making the overall camshaft structure more balanced, and placing the center of gravity closer to the center of the shaft 11.

[0041] The drive shaft 11 rotates, driving the intake cam 21 and exhaust cam 31 to rotate. The intake cam 23 and exhaust cam 33 then drive the intake and exhaust valves to open, respectively. During rotation, the intake cam 21 sequentially drives the intake valve to open via the intake lift section 24 and the first intake envelope section 25. Then, the intake opening section 26 supports the intake valve at its maximum opening. Next, the second intake envelope section 27 and the intake drop section 28 drive the intake valve to close. Finally, the intake base circle 22 keeps the intake valve closed. Similarly, during rotation, the exhaust cam 31 sequentially drives the exhaust valve to open via the exhaust lift section 34 and the first exhaust envelope section 35. Then, the exhaust opening section 36 supports the exhaust valve at its maximum opening. Next, the second exhaust envelope section 37 and the exhaust drop section 38 drive the exhaust valve to close. Finally, the exhaust base circle 32 keeps the exhaust valve closed.

[0042] This embodiment has the following advantages:

[0043] The angular amplitude of the first intake envelope section 25, the intake opening section 26, and the second intake envelope section 27 is 90.5°, while the angular amplitude of the first exhaust envelope section 35, the exhaust opening section 36, and the second exhaust envelope section 37 is 85°. The larger angular amplitude of the first intake envelope section 25, the intake opening section 26, and the second intake envelope section 27 compared to the first exhaust envelope section 35, the exhaust opening section 36, and the second exhaust envelope section 37 increases the time the intake valve is at its maximum opening, reducing the resistance of the intake valve to the air entering the engine. This allows air to enter the engine more smoothly, ensuring sufficient oxygen for combustion in the combustion chamber, thus guaranteeing complete fuel combustion and improving combustion efficiency. This optimizes the intake and exhaust coordination during engine operation, improving engine performance and thermal efficiency while reducing combustion consumption.

[0044] By setting the first intake envelope section 25, the process of the intake valve transitioning from the intake lift section 24 to the intake opening section 26 is made more stable. By setting the second intake envelope section 27, the process of the intake valve transitioning from the intake opening section 26 to the intake fall section 28 is made more stable, thereby improving the stability of the intake valve movement.

[0045] A laser generator and a laser sensor are installed on the engine. The laser generator emits a laser beam towards the measuring wheel 13. When the measuring groove 14 rotates to the position of the laser generator, the laser beam emitted by the laser generator is reflected by the inclined surface 15 onto the laser sensor, causing the laser sensor to emit a detection signal. The laser sensor receives the laser beam and emits a detection signal every time the shaft 11 rotates one revolution. The rotation frequency of the shaft 11 can be determined based on the time interval of the detection signals, which is calculated as 1 second divided by the interval of the detection signals. When the laser generator is misaligned from the measuring groove 14, there is no inclined surface 15 to reflect the laser beam, preventing the laser beam emitted by the laser generator from reflecting onto the laser sensor. This effectively prevents light leakage and avoids the laser sensor emitting incorrect detection signals, thus improving detection accuracy.

[0046] Based on the disclosure and teachings of the above specification, those skilled in the art can make changes and modifications to the above embodiments. Therefore, this utility model is not limited to the specific embodiments disclosed and described above, and some modifications and changes to the utility model should also fall within the protection scope of the claims of this utility model. Furthermore, although some specific terms are used in this specification, these terms are only for convenience of explanation and do not constitute any limitation on the utility model.

Claims

1. A low-angle camshaft characterized by: The application relates to a camshaft (11) comprising an axle body (11), an intake cam (21) and an exhaust cam (31), wherein the intake cam (21) and the exhaust cam (31) are arranged on the axle body (11), the intake cam (21) comprises an intake base circle (22) and an intake cam lobe (23), the intake base circle (22) is fixedly connected with the axle body (11), the intake cam lobe (23) is fixedly connected with the intake base circle (22), the outer contour of the intake cam lobe (23) is sequentially provided with an intake lift section (24), a first intake wrap angle section (25), an intake opening section (26), a second intake wrap angle section (27) and an intake drop section (28) along the circumference of the axle body (11), the exhaust cam (31) comprises an exhaust base circle (32) and an exhaust cam lobe (33), the exhaust base circle (32) is fixedly connected with the axle body (11), the exhaust cam lobe (33) is fixedly connected with the exhaust base circle (32), the outer contour of the exhaust cam lobe (33) is sequentially provided with an exhaust lift section (34), a first exhaust wrap angle section (35), an exhaust opening section (36), a second exhaust wrap angle section (37) and an exhaust drop section (38) along the circumference of the axle body (11), and the turning angle amplitudes of the first intake wrap angle section (25), the intake opening section (26) and the second intake wrap angle section (27) are greater than those of the first exhaust wrap angle section (35), the exhaust opening section (36) and the second exhaust wrap angle section (37).

2. The low-angle crowning camshaft of claim 1, wherein: The two ends of the first intake wrap angle section (25) are smoothly connected with the intake lift section (24) and the intake opening section (26) respectively, and the two ends of the second intake wrap angle section (27) are smoothly connected with the intake opening section (26) and the intake drop section (28) respectively.

3. The low-angle crowning camshaft of claim 1, wherein: The two ends of the first exhaust wrap angle section (35) are smoothly connected with the exhaust lift section (34) and the exhaust opening section (36) respectively, and the two ends of the second exhaust wrap angle section (37) are smoothly connected with the exhaust opening section (36) and the exhaust drop section (38) respectively.

4. The low-angle crowning camshaft of claim 1, wherein: The circular arc radius of the first intake wrap angle section (25) is greater than that of the second intake wrap angle section (27).

5. The low-angle crowning camshaft of claim 1, wherein: The turning angle of the intake lift section (24) is 0-27.1 degrees, the turning angle of the first intake wrap angle section (25) is 27.1-58.4 degrees, the turning angle of the intake opening section (26) is 58.4-86.3 degrees, the turning angle of the second intake wrap angle section (27) is 86.3-117.6 degrees, the turning angle of the intake drop section (28) is 117.6-144.7 degrees, and the turning angle of the intake base circle (22) is 144.7-360 degrees.

6. The low-packet-angle camshaft of claim 1, wherein: The turning angle of the exhaust lift section (34) is 0-35 degrees, the turning angle of the first exhaust wrap angle section (35) is 35-44.4 degrees, the turning angle of the exhaust opening section (36) is 44.4-75.6 degrees, the turning angle of the second exhaust wrap angle section (37) is 75.6-85 degrees, the turning angle of the exhaust drop section (38) is 85-120 degrees, and the turning angle of the exhaust base circle (32) is 120-360 degrees.

7. The low-angle crowning camshaft of claim 1, wherein: The intake air ascending section (24) is smoothly connected with the intake base circle (22) at one end away from the first intake air wrap angle section (25), and the intake air descending section (28) is smoothly connected with the intake base circle (22) at one end away from the second intake air wrap angle section (27).

8. The low-packet-angle camshaft of claim 1, wherein: The exhaust air ascending section (34) is smoothly connected with the exhaust base circle (32) at one end away from the first exhaust air wrap angle section (35), and the exhaust air descending section (38) is smoothly connected with the exhaust base circle (32) at one end away from the second exhaust air wrap angle section (37).

9. The low-packet-angle camshaft of claim 1, wherein: The intake cam (21) and the exhaust cam (31) are provided in plurality, and the plurality of intake cams (21) and the plurality of exhaust cams (31) are one-to-one corresponding.

10. The low-packet-angle camshaft of claim 1, wherein: The shaft body (11) is fixedly connected with a belt pulley (12) and a measuring wheel (13), the intake cam (21) and the exhaust cam (31) are located between the belt pulley (12) and the measuring wheel (13), the measuring wheel (13) is provided with a measuring groove (14), and the bottom of the measuring groove (14) is provided with an inclined surface (15).

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