Pressure relief cam shaft structure for internal combustion engine pressure relief device

Abstract

The application relates to a pressure-reducing cam shaft structure of a pressure-reducing device of an internal combustion engine, wherein the pressure-reducing device is arranged on a cam shaft, the cam shaft has an intake cam and an exhaust cam; the pressure-reducing device has a first supporting base arranged along the axial direction of the cam shaft, a second supporting base arranged on the cam shaft and spaced from the first supporting base, a swing arm driven to swing by the cam shaft, a reset unit arranged on the cam shaft and driven to act on the swing arm, and a pressure-reducing cam shaft driven by the swing arm; the first supporting base is provided with a first through hole or a first through hole, and the second supporting base is provided with a second through hole; the pressure-reducing cam shaft has at least a pressure-reducing cam section and a pivot section arranged on one side of the pressure-reducing cam section; the pressure-reducing cam shaft is arranged in the first through hole or the first through hole of the first supporting base and the second through hole of the second supporting base, so that the pressure-reducing cam shaft is pivoted on the first supporting base and the second supporting base; and the pressure-reducing cam shaft maintains the required rigidity and strength, and the use efficiency of the pressure-reducing device is improved.

Description

Technical Field

[0001] This invention relates to a decompression camshaft structure for an internal combustion engine decompression device, and more particularly to a decompression camshaft structure for an internal combustion engine decompression device that ensures the positioning and rigidity of the decompression camshaft. Background Technology

[0002] As shown in Figure 1, at the start of the internal combustion engine 1, in order to avoid excessive resistance when the piston 11 in the internal combustion engine 1 rises from the bottom dead center, a pressure reducing device 14 is installed on the camshaft 13 in the cylinder head 12.

[0003] The pressure relief device 14 is located on the side of the exhaust cam 131 of the camshaft 13. When the internal combustion engine 1 is about to start, the pressure relief device 14 pushes the exhaust rocker arm 15. After the exhaust rocker arm 15 is pushed by the pressure relief device 14, the exhaust valve (not shown in the figure) is opened slightly. So when the internal combustion engine 1 starts, the air pressure generated by the piston 11 pushing upward from the bottom dead center to the combustion chamber 16 can be discharged through the slightly opened exhaust valve, thereby reducing the resistance when the piston 11 pushes upward from the bottom dead center, so as to facilitate the starting of the internal combustion engine 1.

[0004] As shown in Figure 1, the pressure reducing device 14 has at least a swing arm 141 and a pressure reducing camshaft 142 that can be driven by the swing arm 141. When the internal combustion engine 1 is not started, the swing arm 141 is slightly retracted on the camshaft 13. Therefore, the swing arm 141 can drive the pressure reducing camshaft 142 to slightly push the exhaust cam 131. The exhaust cam 131 can slightly abut the exhaust rocker arm 15, thereby making the exhaust valve slightly open, so that the internal combustion engine 1 can achieve the purpose of pressure reduction when it is started. A smaller diameter insertion shaft 1421 extends along one side of the pressure-reducing camshaft 142. The pressure-reducing camshaft 142 is pivotally inserted into the side wall of the exhaust cam 131 via the insertion shaft 1421. More specifically, the pressure-reducing camshaft 142 is cantilevered to the side of the exhaust cam 131 via the insertion shaft 1421. Thus, the pressure-reducing camshaft 142 rotates at a preset angle around the insertion shaft 1421 as its rotation center, driven by the swing arm 141, thereby reducing pressure. The camshaft 142 pushes or does not push the exhaust rocker arm 15 to achieve the effect of decompression; however, the decompression camshaft 142 is actuated by the insertion shaft 1421 being mounted on one side of the exhaust cam 131 in a cantilever manner, that is, the decompression camshaft 142 is driven by the rocker arm 141 in a cantilever manner. Since the diameter of the insertion shaft 1421 is small, the insertion shaft 1421 will become a stress point and cause it to break, thus causing the decompression device 14 to fail to perform its decompression purpose.

[0005] Therefore, how to provide a pressure-reducing camshaft structure for an internal combustion engine pressure-reducing device to avoid damage to the pressure-reducing camshaft in the pressure-reducing device, thereby ensuring the usability of the pressure-reducing device, has become an urgent issue for internal combustion engine manufacturers to address. Summary of the Invention

[0006] The problem that the invention aims to solve. The main objective of this invention is to provide a decompression camshaft structure for an internal combustion engine decompression device, thereby overcoming the disadvantage that the decompression camshaft in the existing internal combustion engine decompression device is driven by a swing arm in a cantilever manner, which leads to easy damage to the decompression camshaft.

[0007] Technical means to solve the problem Therefore, some embodiments of the present invention provide a decompression camshaft structure for a decompression device of an internal combustion engine. The decompression device is mounted on a camshaft, which has an intake cam and an exhaust cam. The decompression device includes a first support seat arranged axially upward along the camshaft, a second support seat disposed on the camshaft and spaced apart from the first support seat, a swing arm that can be driven and oscillated by the camshaft, a reset unit disposed on the camshaft and interacting with the swing arm, and a decompression camshaft that can be driven by the swing arm. The first support seat has a first through hole or a first through hole, and the second support seat has a second through hole. The decompression camshaft has at least a decompression cam section and a pivot section extending from one side of the decompression cam section. The decompression camshaft passes through the first through hole of the first support seat or the first through hole and the second through hole of the second support seat, so that the decompression camshaft is pivotally mounted on the first support seat and the second support seat in a manner supported on both sides.

[0008] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device, wherein the first support and the second support are integrally formed with the camshaft.

[0009] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device, wherein the first support is arranged side by side with the exhaust cam along the axial direction of the camshaft; the first support may also be formed by a part of the exhaust cam.

[0010] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device. The decompression camshaft has a first limiting mechanism at the outer end of the first support opposite to the second support, and a second limiting mechanism at the outer end of the second support opposite to the first support. The first limiting mechanism and the second limiting mechanism can limit the displacement of the decompression camshaft along the axial direction of the camshaft.

[0011] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device, wherein the camshaft is further fitted with a first bearing, the first bearing having an outer ring portion, an inner ring portion and a ball portion located between the outer ring portion and the inner ring portion; the first limiting mechanism may be an exhaust cam sidewall provided on the aforementioned camshaft, or another component on the camshaft and located between the exhaust cam and the first support seat; the second limiting mechanism is formed by the inner ring portion of the first bearing.

[0012] Therefore, some embodiments of the present invention provide a decompression camshaft structure for a decompression device of an internal combustion engine, wherein the pivot section of the decompression camshaft is defined as a first support section by passing through a first through hole in a first support seat, and the pivot section is defined as a second support section by passing through a second through hole in a second support seat, wherein the diameter of the second support section is greater than or equal to the diameter of the first support section.

[0013] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device, wherein the diameter of the decompression cam section of the aforementioned decompression camshaft is smaller than the diameters of the second support section and the first support section.

[0014] Therefore, some embodiments of the present invention provide a decompression camshaft structure for a decompression device of an internal combustion engine. The decompression camshaft has an insertion portion extending to one side of the decompression cam section, and a pivot head extending to one side of the pivot section. The decompression camshaft as a whole has multiple portions with different diameters, and the overall diameter of the decompression camshaft from smallest to largest is as follows: the insertion portion, the decompression cam section, the pivot section, and the pivot head.

[0015] Therefore, some embodiments of the present invention provide a decompression camshaft structure for a decompression device of an internal combustion engine. The pivot section has a cutout in the radial direction, and the pivot section has an insertion hole in the radial direction adjacent to the decompression cam section. The entrance of the insertion hole has a push-pull shaped hole, and the insertion hole can accommodate an actuating pin, which is located between the first support and the second support.

[0016] Therefore, some embodiments of the present invention provide a decompression camshaft structure for a decompression device of an internal combustion engine, wherein the pivot section has an adjustment groove at its side end.

[0017] Therefore, some embodiments of the present invention provide a decompression camshaft structure for an internal combustion engine decompression device, wherein the first support seat can be formed by providing a first through hole in the side wall of the exhaust cam.

[0018] [The effects of the invention] The advantages achieved by the present invention through some embodiments are as follows: both ends of the pressure-reducing camshaft can be supported, thus preventing the pressure-reducing camshaft from being driven by the swing arm in a cantilever manner, thereby allowing the pressure-reducing camshaft to maintain its due rigidity and strength; at the same time, on the one hand, the pressure-reducing camshaft has better positioning and support, and on the other hand, it avoids the pressure-reducing camshaft being damaged by being set in a cantilever manner, thereby improving the effectiveness of the pressure-reducing device.

[0019] The advantages that this invention can achieve through some embodiments are that it simplifies the manufacturing process and procedures of the pressure reducing device.

[0020] The advantages that this invention can achieve through some embodiments are that it simplifies the limiting displacement mechanism of the pivot.

[0021] The advantages achieved by the present invention through some embodiments are that it can prevent the pressure-reducing camshaft from dislodging, thereby improving the safety of the pressure-reducing device.

[0022] The advantages achieved by the present invention through some embodiments are that it can prevent the pressure-reducing camshaft from dislodging, thereby improving the safety of the pressure-reducing device.

[0023] The effect achieved by the present invention through some embodiments is that it can improve the rigidity and strength of the pressure-reducing camshaft.

[0024] The advantages achieved by the present invention through some embodiments are that it can avoid interference caused by the deformation of the camshaft after heat treatment.

[0025] The effect achieved by the present invention through some embodiments is that it can improve the rigidity and strength of the pressure-reducing camshaft.

[0026] The effect achieved by the present invention through some embodiments is that it can ensure the stability of the pressure-reducing camshaft during operation.

[0027] The advantages that this invention can achieve through some embodiments are: thereby facilitating the directional effect and convenience of the sales process.

[0028] The advantages that this invention can achieve through some embodiments are that it facilitates the installation of the camshaft. Attached Figure Description

[0029] Figure 1 is a schematic diagram of the decompression camshaft structure of a conventional internal combustion engine decompression device.

[0030] Figure 2 is a schematic diagram of the decompression camshaft structure of the internal combustion engine decompression device of the present invention.

[0031] Figure 3 is an exploded view of the pressure reduction device of the present invention.

[0032] Figure 4 is a schematic diagram of the pressure reduction device assembly of the present invention.

[0033] Figure 5 is a cross-sectional view of the camshaft of the present invention.

[0034] Figure 6 is a cross-sectional view of the camshaft and pressure reducing device of the present invention.

[0035] Figures 7, 8, 9, and 10 are schematic diagrams of the operation of the pressure-reducing device of the present invention.

[0036] Figures 11 and 12 show another embodiment of the pressure-reducing camshaft of the pressure-reducing device of the present invention.

[0037] Figures 13 and 14 are embodiments of the internal combustion engine of the present invention.

[0038] List of reference numerals 1: Internal combustion engine 11: Piston; 12: Cylinder head 13: Camshaft 131: Exhaust Cam 14: Pressure reducing device 141: Swing arm; 142: Pressure reducing camshaft; 1421: Insertion shaft 143: Pivot 144: Support 15: Exhaust rocker arm 16: Combustion chamber 2: Pressure reducing device 21: First support seat 211: First shaft hole; 212: First through hole 22: Second support seat 221: Second shaft hole; 222: Second through hole; 223: Limiting groove 23: Swing arm 231: Pivot hole; 232: Top support portion 233: Actuating part 2331: Notch / groove 234: Limiting protrusion; 24: Reset unit 241: Pushing component; 2411: Pushing part; 2412: Rod part; 242: Elastic element 25: Pressure-reducing camshaft 251: Pressure Reduction Cam Section 2511: Arc surface; 2512: Flat sectional surface; 251a: Insertion part 252: Pivotal Section 2521: Incision site; 252a: Pivoted head. 253: Insertion hole; 254: Action pin 255: Adjustment slot 26: Pivot 3: Camshaft 31: Exhaust Cam 31a: First perforation 311: Groove 32: Intake Cam 33: First Bearing 331: Outer ring section; 332: Inner ring section 333: Ball bearing section 34: Second bearing 35: Receiving groove 36: Exhaust rocker arm 3a: Central axis 4: Two-wheeled vehicle 41: Chassis Unit 42: Steering Mechanism 43: Seating Unit A: Internal combustion engine A1: Cylinder section; A2: Piston assembly A3: Crankshaft A4: Continuously Variable Transmission (CVT) A41: Variable speed belt; A42: Output shaft A5: Transmission Unit A51: Drive shaft; A52: Drive belt A6: Electrical components A7: Liquid Cooling Radiator Assembly A71: Cooling tank; A72: Cooling fan A8: Rear swingarm A9: Exhaust device M: First support segment M1: Second support segment T: First restriction mechanism; T1: Second restriction mechanism RW: Rear wheel. Detailed Implementation

[0039] To better understand the structure and effects of this invention, the following description is provided in conjunction with the accompanying drawings.

[0040] First, please refer to Figures 2, 3, and 4, which show the decompression camshaft structure of the internal combustion engine decompression device of the present invention. The decompression device 2 is assembled on the camshaft 3 and is adjacent to the exhaust cam 31 of the camshaft 3. The decompression device 2 includes a first support seat 21 disposed on the camshaft 3, a second support seat 22 disposed on the camshaft 3 and spaced apart from the first support seat 21, a swing arm 23 pivotally disposed on the first support seat 21 and the second support seat 22, a reset unit 24 disposed on the camshaft 3 and capable of abutting the swing arm 23, and a decompression camshaft 25 that can be driven by the swing arm 23.

[0041] As shown in Figures 2, 3, 4, and 5, the first support seat 21 is arranged side-by-side with the exhaust cam 31 along the axial direction of the camshaft 3. That is, the first support seat 21 can also be formed as a part of the exhaust cam 31, or the first support seat 21 can be integrally formed on the camshaft 3, or the first support seat 21 can be formed as another component tightly fitted to the camshaft 3. The first support seat 21 is adjacent to the exhaust cam 31. More specifically, the first support seat 21 is installed on the side of the exhaust cam 31 away from the intake cam 32. That is, the intake cam 32, the exhaust cam 31, and the first support seat 21 are sequentially arranged on the camshaft 3. The first support seat 21 is provided with a first shaft hole 211. The first support seat 21 is provided with a first through hole 212 on the other side of the first support seat 21. The exhaust cam 31 is recessed with an open groove 311 on the side corresponding to the first through hole 212 of the first support seat 21.

[0042] As shown in Figures 2, 3, 4, and 5, the second support seat 22 is integrally formed on the camshaft 3, or is axially fitted onto the camshaft 3 as another component. The second support seat 22 is disposed on the camshaft 3 at a distance from the first support seat 21. More specifically, the second support seat 22 is installed on the side of the first support seat 21, away from the exhaust cam 31. That is, the camshaft 3 is axially arranged with the intake cam 32, exhaust cam 31, first support seat 21, and second support seat 22 in sequence. The second support seat 22 is provided with a second shaft hole 221, which corresponds to the first shaft hole 211 of the first support seat 21. The first through hole 212 of the first support base 21 should also be provided with a second through hole 222. The second support base 22 is provided with a limiting groove 223 on the side where the second shaft hole 221 and the second through hole 222 are provided. The camshaft 3 is provided with a first bearing 33 on the side of the second support base 22 away from the first support base 21. The first bearing 33 has an outer ring portion 331, an inner ring portion 332 and a ball portion 333 located between the outer ring portion 331 and the inner ring portion 332. The inner ring portion 332 of the first bearing 33 is connected to the camshaft 3 in a tight fit manner, so that the inner ring portion 332 of the first bearing 33 can be rotated synchronously by the camshaft 3. The camshaft 3 is also provided with a second bearing 34 on the side of the intake cam 32.

[0043] As shown in Figures 2, 3, and 6, the swing arm 23 is an arc-shaped body. One end of the swing arm 23 has a pivot hole 231, which corresponds to the first shaft hole 211 of the first support 21 and the second shaft hole 221 of the second support 22. A pivot 26 can be inserted through the second shaft hole 221 of the second support 22, the pivot hole 231 of the swing arm 23, and the first shaft hole 211 of the first support 21, allowing the swing arm 23 to swing freely around the pivot 26 as its swing center. When the pivot 26 is inserted through the second shaft hole 221 of the second support 22 and the first shaft hole 211 of the first support 21, ... The pivot arm 23 is tightly fitted with one of the second shaft holes 221 or the first shaft hole 211, while the pivot arm 23 is slidably connected to the pivot 26. The pivot arm 23 is pivotally mounted on the second shaft hole 221 of the second support 22 and the first shaft hole 211 of the first support 21 via the pivot 26, thus allowing both ends of the pivot 26 to be supported. This avoids the pivot 26 being cantilevered for the pivot arm 23 to pivot, thereby ensuring that the pivot 26 maintains its required rigidity. The camshaft 3 has a central axis 3a, and the pivot 26 is arranged parallel to the central axis 3a of the camshaft 3. The pivot 26 is located on the first support 21. The outer end is restricted in displacement by the sidewall of the exhaust cam 31, meaning that the sidewall of the exhaust cam 31 forms a first limiting mechanism T for the pivot 26 located at the outer end of the first support 21. In practice, the so-called first limiting mechanism T can be constructed by fitting another component onto the camshaft 3 and located between the exhaust cam 31 and the first support 21. The outer end of the pivot 26 located at the second support 22 is restricted by the first bearing 33, more specifically, by the inner ring portion 332 of the first bearing 33, meaning that the inner ring portion 332 of the first bearing 33 forms a second limiting mechanism for the pivot 26 located at the outer end of the second support 22. Furthermore, it is worth mentioning that the axial length of the pivot 26 inserted into the second support 22 is greater than the axial clearance between the first support 21 and the first limiting mechanism T, and the radial outward dimension of the pivot 26 along the camshaft 3 does not exceed the inner edge of the outer ring portion 331 of the first bearing 33. More specifically, the two ends of the pivot 26 are respectively limited by the first limiting mechanism T and the second limiting mechanism T1 in terms of the amount of displacement along the axial direction of the camshaft 3. In this way, the pivot 26 can have better positioning and support, and neither end of the pivot 26 needs to be riveted to maintain its positioning, thereby further preventing damage to the rigidity of the pivot 26.

[0044] As shown in Figures 2, 3, 6, and 7, the swing arm 23 has a supporting portion 232 extending outward at one end of the pivot hole 231, and an actuating portion 233 at the other end of the supporting portion 232. The actuating portion 233 has a notch 2331 opened laterally from the swing arm 23. A limiting protrusion 234 is provided on the side of the swing arm 23 between the supporting portion 232 and the actuating portion 233. The limiting protrusion 234 is correspondingly provided with the limiting groove 223 of the second support seat 22, thereby limiting the swing position of the swing arm 23.

[0045] As shown in Figures 3, 4, 5, 6, and 7, the camshaft 3 has a radially arranged receiving groove 35 between the second support 22 and the first support 21. The reset unit 24 is embedded in the receiving groove 35 of the camshaft 3. The reset unit 24 can be composed of a single elastic element or a combination of an elastic element and a pusher element. The reset unit 24 of this invention is illustrated by an example of an elastic element and a pusher element. The reset unit 24 has a pusher element 241 and is sleeved on the... The pusher 241 has an elastic element 242 on its outer periphery; the pusher 241 has a pusher portion 2411 with a large outer diameter and a rod portion 2412 extending to one side from the pusher portion 2411. The elastic element 242 is located below the pusher portion 2411 and on the outer periphery of the rod portion 2412. The pusher portion 2411 of the pusher 241 abuts against the holding portion 232 of the swing arm 23. In this way, the reset unit 24 can perform push and press actions with the swing arm 23.

[0046] As shown in Figures 2, 3, 4, 6, 7, and 8, the pressure-reducing camshaft 25 has a pressure-reducing cam section 251 located on the side of the exhaust cam 31 and a pivoting section 252 extending from the pressure-reducing cam section 251 to one side; the pressure-reducing cam section 251 has an arcuate surface 2511 that can slightly push the exhaust rocker arm 36 and a flat surface 2512, the arcuate surface 2511 slightly protruding from the base circle of the exhaust cam 31; the pivoting section 252 can be pivoted through the first through hole 212 of the first support seat 21 and the second through hole 222 of the second support seat 22, the pivoting section 252 is pivoted through After the first through hole 212 of the first support seat 21 and the second through hole 222 of the second support seat 22 are connected, the portion of the pivoting segment 252 that is pivoted through the first through hole 212 of the first support seat 21 is defined as the first support segment M, and the portion of the pivoting segment 252 that is pivoted through the second through hole 222 of the second support seat 22 is defined as the second support segment M1. The diameter of the second support segment M1 of the pivoting segment 252 is greater than or equal to the diameter of the first support segment M, and at the same time, the diameter of the pressure-reducing cam segment 251 is smaller than the diameters of the second support segment M1 and the first support segment M. This can improve the rigidity of the pressure-reducing camshaft 25; the pivot section 252 has a radially oriented notch 2521, and the pivot section 252 has a radially oriented insertion hole 253 near the notch 2521 and the pressure-reducing cam section 251. The insertion hole 253 has a push-pull shaped hole at its entrance, and an actuating pin 254 can be inserted into the insertion hole 253. The other end of the actuating pin 254 is embedded in the notch 2331 of the actuating part 233 of the swing arm 23, thereby driving the actuating pin 254 when the swing arm 23 performs a swinging action, thus the swing arm 23 can drive the pressure-reducing camshaft 25 to rotate; when the pressure-reducing camshaft 25 is pivotally connected to the first support 21 and the second support 22 via the pivot section 252, the actuating pin 254 is located between the first support 21 and the second support 22; the pressure-reducing camshaft 25 has an adjustment groove 255 on the end face of the pivot section 252 away from the exhaust cam 31, so that after the pressure-reducing camshaft 25 is installed, the engineer can use a tool to insert into the adjustment groove 255 to rotate the pressure-reducing camshaft 25 to adjust the correct angle of the pressure-reducing camshaft 25 after installation.The pressure-reducing camshaft 25 is arranged parallel to the central axis 3a of the camshaft 3. When the pressure-reducing camshaft 25 is pivotally connected to the first through hole 212 of the first support 21 and the second through hole 222 of the second support 22 via the pivot section 252, the outer end of the pressure-reducing camshaft 25 located on the first support 21 (i.e., the outer end of the pressure-reducing cam section 251) is restricted in its displacement by the side wall of the exhaust cam 31. That is, the side wall of the exhaust cam 31 forms a first limiting mechanism T for the pressure-reducing camshaft 25 located on the outer end of the first support 21. In practice, the so-called first limiting mechanism T can be sleeved on the camshaft 3 and located between the exhaust cam 31 and the first support 21. The pressure-reducing camshaft 25 is constituting the outer end of the second support 22, which is restricted by the first bearing 33, or more specifically, by the inner ring portion 332 of the first bearing 33. That is, the inner ring portion 332 of the first bearing 33 forms a second limiting mechanism T1 for the pressure-reducing camshaft 25 located at the outer end of the second support 22. Accordingly, the two ends of the pressure-reducing camshaft 25 are respectively restricted by the first limiting mechanism T and the second limiting mechanism T1 to limit the displacement along the axial direction of the camshaft 3. In this way, the pressure-reducing camshaft 25 can have better positioning and support, and the rigidity of the pressure-reducing camshaft 25 can be avoided by setting it in a cantilever manner.

[0047] As shown in Figures 11 and 12, in the implementation of the pressure-reducing camshaft 25 of the present invention, a smaller diameter insertion portion 251a extends to one side of the pressure-reducing cam segment 251, and a larger diameter pivot head 252a extends to one side of the pivot segment 252. Accordingly, the overall diameter of the pressure-reducing camshaft 25 has multiple different diameters. More specifically, the overall diameter of the pressure-reducing camshaft 25, from smallest to largest, is as follows: insertion portion 251a, pressure-reducing cam segment 251, pivot segment 252, and pivot head 252a. Furthermore, the pressure-reducing camshaft 25 further includes the insertion portion 251a and the pivot head 252a. The first support seat 21 is integrally formed on the camshaft 3 and integrally formed with the exhaust cam 31. It is formed on the side of the exhaust cam 31, or the first support seat 21 is formed by a first through hole 31a provided on the side wall of the exhaust cam 31. The figure shows the first through hole 31a provided on the side wall of the exhaust cam 31. The insertion part 251a of the decompression camshaft 25 is inserted into the first through hole 31a of the exhaust cam 31, and the pivot head 252a of the decompression camshaft 25 is inserted into the second through hole 222 of the second support seat 22. In this way, both sides of the decompression camshaft 25 can be supported at the same time.

[0048] As shown in Figures 13 and 14, the present invention is illustrated using an internal combustion engine A implemented in a two-wheeled vehicle 4 as an example, but this does not limit the scope of application of the internal combustion engine A. The two-wheeled vehicle 4 has at least a frame unit 41, with a steering mechanism 42 at its front end and a passenger seat 43 for the driver at its rear. The internal combustion engine A is suspended on the frame unit 41 and located below the passenger seat 43. The internal combustion engine A has a cylinder section A1, a piston assembly A2 extending into the cylinder section A1, a crankshaft A3 driven by the piston assembly A2, a continuously variable transmission (CVT) system A4 driven by the crankshaft A3, and a transmission unit A5 driven by the CVT system A4. The crankshaft A3 is connected to the CVT system... On the other side of the continuously variable transmission (CVT) A4, there is a motor component A6 and a liquid-cooled radiator assembly A7; the CVT A4 has a transmission belt A41 and an output shaft A42; the transmission unit A5 has a drive shaft A51, which is equipped with a drive belt A52 that can drive the rear wheel RW, and a freely swinging rear rocker arm A8 is pivotally mounted on the outer sides of both ends of the drive shaft A51; the drive shaft A51 and the output shaft A42 are arranged coaxially; the liquid-cooled radiator assembly A7 has a radiator tank A71 and a radiator fan A72; the internal combustion engine A has an exhaust device A9 on the side of the CVT A4.

[0049] As shown in Figures 2, 7, 8, 9, and 10, in the implementation of the pressure reducing device 2 of the present invention, when the internal combustion engine A is not started, the pressure reducing device 2 can push the supporting part 232 of the swing arm 23 by the reset unit 24. In this way, the actuating part 233 of the swing arm 23 can drive the pressure reducing camshaft 25 to rotate by a preset angle via the actuating pin 254. This allows the arc surface 2511 of the pressure reducing cam section 251 to slightly protrude from the base circle of the exhaust cam 31, thus pushing the exhaust rocker arm 36 and causing the exhaust valve to open slightly. When the internal combustion engine A is started, the swing arm 23 of the pressure reducing device 2 will swing around the pivot 26 as its swing center due to the centrifugal force generated by the rotation of the camshaft 3. After the swing arm 23 swings, it will further drive the pressure reducing camshaft 25 via the actuating part 233. The actuating pin 254 causes the pivot section 252 of the pressure-reducing camshaft 25 to rotate at a larger angle around the rotation center. This allows the arc surface 2511 of the pressure-reducing cam section 251 of the pressure-reducing camshaft 25 to screw into the groove 311, while the flat surface 2512 of the pressure-reducing cam section 251 screws out of the groove 311. As a result, the arc surface 2511 of the pressure-reducing cam section 251 of the pressure-reducing camshaft 25 no longer protrudes from the base circle of the exhaust cam 31, and the pressure-reducing cam section 251 of the pressure-reducing camshaft 25 no longer pushes the exhaust rocker arm 36. In addition, since the limiting protrusion 234 of the swing arm 23 is inserted into the limiting groove 223 of the second support 22, the rotation amplitude of the pressure-reducing camshaft 25 can be limited by the mutual limiting effect of the limiting protrusion 234 of the swing arm 23 and the limiting groove 223 of the second support 22.

[0050] The advantage of this invention lies in that, by means of the pressure-reducing device 2 mounted on a camshaft 3, the camshaft 3 having an intake cam 32 and an exhaust cam 31, and the camshaft 3 having a receiving groove 35 at the end of the exhaust cam 31; the pressure-reducing device 2 includes a first support seat 21 mounted on the camshaft 3, a second support seat 22 mounted on the camshaft 3 and spaced apart from the first support seat 21, a swing arm 23 that can be driven and oscillated by the camshaft 3, a reset unit 24 mounted on the camshaft 3 and capable of interacting with the swing arm 23, and a pressure-reducing camshaft 25 that can be driven by the swing arm 23; the first support seat 21 has a first through hole 212, and the second support seat 22 has a second through hole 222; The pressure-reducing camshaft 25 has at least a pressure-reducing cam section 251 and a pivot section 252 extending from one side of the pressure-reducing cam section 251. The pressure-reducing camshaft 25 is pivotally mounted on the first support 21 and the second support 22 by means of the pivot section 252 passing through the first through hole 212 of the first support 21 and the second through hole 222 of the second support 22, so that the pressure-reducing camshaft 25 is supported on both sides. In this way, both ends of the pressure-reducing camshaft 25 can be supported, thus preventing the pressure-reducing camshaft 25 from being driven by the swing arm 23 in a cantilever manner. Accordingly, the pressure-reducing camshaft 25 can maintain the required rigidity and strength, thereby improving the efficiency of the pressure-reducing device 2.

[0051] In conclusion, the structure of this invention does indeed achieve the claimed purpose and should meet the requirements of novelty, inventiveness and utility for invention patents.

Claims

1. A pressure-reducing camshaft structure for an internal combustion engine pressure-reducing device, wherein the pressure-reducing device is mounted on a camshaft, and the camshaft has an intake cam and an exhaust cam, characterized in that, The pressure-reducing device includes a first support seat arranged axially upward along the camshaft, a second support seat disposed on the camshaft and spaced apart from the first support seat, a swing arm that can be driven and oscillated by the camshaft, a reset unit disposed on the camshaft and capable of interacting with the swing arm, and a pressure-reducing camshaft that can be driven by the swing arm; the first support seat has a first through hole, and the second support seat has a second through hole; the pressure-reducing camshaft has at least a pressure-reducing cam section and a pivot section extending from one side of the pressure-reducing cam section, and the pressure-reducing camshaft passes through the first through hole of the first support seat and the second through hole of the second support seat, so that the pressure-reducing camshaft is pivotally mounted on the first support seat and the second support seat in a manner that is supported on both sides.

2. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The first support and the second support are integrally formed with the camshaft.

3. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The first support is arranged side-by-side with the exhaust cam along the camshaft axis; or the first support is formed by a portion of the exhaust cam.

4. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The pressure-reducing camshaft has a first limiting mechanism at the outer end of the first support opposite to the second support, and a second limiting mechanism at the outer end of the second support opposite to the first support. The first limiting mechanism and the second limiting mechanism can limit the displacement of the pressure-reducing camshaft along the axial direction of the camshaft.

5. The decompression camshaft structure of the internal combustion engine decompression device according to claim 4, characterized in that, The camshaft is further fitted with a first bearing, which has an outer ring portion, an inner ring portion, and a ball portion located between the outer ring portion and the inner ring portion; the first limiting mechanism is an exhaust cam sidewall provided on the aforementioned camshaft, or another component on the camshaft located between the exhaust cam and the first support seat; the second limiting mechanism is formed by the inner ring portion of the first bearing.

6. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The portion of the pivot section of the pressure-reducing camshaft that passes through the first through hole of the first support seat is defined as the first support section, and the portion of the pivot section that passes through the second through hole of the second support seat is defined as the second support section. The diameter of the second support section of the pivot section is greater than or equal to the diameter of the first support section.

7. The decompression camshaft structure of the internal combustion engine decompression device according to claim 6, characterized in that, The diameter of the pressure-reducing cam section of the aforementioned pressure-reducing camshaft is smaller than the diameters of the second support section and the first support section.

8. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The pressure-reducing camshaft has an insertion part extending to one side of the pressure-reducing cam section, and a pivot head extending to one side of the pivot section; the pressure-reducing camshaft as a whole has multiple parts with different diameters, and the overall diameter of the pressure-reducing camshaft from smallest to largest is as follows: the insertion part, the pressure-reducing cam section, the pivot section, and the pivot head.

9. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, characterized in that, The pivot section has a cutout in the radial direction, and the pivot section has an insertion hole in the radial direction adjacent to the decompression cam section. The entrance of the insertion hole has a push-pull shaped hole, and the insertion hole can accommodate an actuating pin. The actuating pin is located between the first support and the second support.

10. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1, 6, 8, or 9, characterized in that, The pivot section is provided with an adjustment groove at its side end.

11. The decompression camshaft structure of the internal combustion engine decompression device according to claim 1 or 3, characterized in that, The first support is formed by providing a first through hole in the side wall of the exhaust cam.

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