Pressure reduction mechanism, valve control structure and engine

Abstract

The utility model relates to a pressure reducing mechanism, a valve control structure and an engine, the pressure reducing mechanism comprises a support, a pressure reducing cam, a pressure reducing rocker arm and a reset spring, the support is provided with a support hole used for being in clearance fit with a cam shaft, a first protrusion is arranged on the peripheral surface of the support in a protruding mode, and a through mounting hole is formed in the first protrusion; the mounting hole is used for being opposite to a pressure reduction groove of the camshaft in the axial direction of the camshaft, the pressure reduction cam is rotatably inserted into the mounting hole and the pressure reduction groove, the pressure reduction rocker arm is arranged on one side of the support and used for being arranged on the periphery of the camshaft, one end of the pressure reduction rocker arm is rotatably connected with the support, and the other end of the pressure reduction rocker arm is in driving connection with the other end of the pressure reduction cam. The decompression cam can be driven by the decompression rocker arm to rotate relative to the support so as to jack up or avoid the valve rocker arm, one end of the reset spring is connected with the support, the other end of the reset spring is connected with the decompression rocker arm, and the reset spring is used for applying tension on the side, close to the cam shaft, of the decompression rocker arm. The pressure reducing mechanism is compact in structure and high in assembling efficiency.

Description

Technical Field

[0001] This application relates to the field of engine technology, and in particular to a decompression mechanism, valve control structure and engine. Background Technology

[0002] The camshaft and decompression mechanism work together to form a valve control structure, primarily used to control the opening and closing of the valves. The decompression mechanism reduces compression resistance during engine startup. Generally, the decompression mechanism includes a decompression cam and a decompression rocker arm. The decompression cam is rotatably mounted in the decompression groove of the camshaft, and the decompression rocker arm drives the decompression cam to rotate relative to the camshaft. Initially during engine startup, the decompression cam lifts the valve rocker arm, keeping the valve slightly open and reducing engine startup energy consumption. As the camshaft speed gradually increases during the initial startup phase, the decompression rocker arm gradually opens, causing the decompression cam to rotate relative to the camshaft. After the engine has started smoothly, the decompression rocker arm fully opens, and the decompression cam rotates to a position where it no longer lifts the valve rocker arm, closing the valve and completing the engine startup.

[0003] In some related technologies, the pressure relief rocker arm is connected to the sprocket located on the camshaft. This is not only not conducive to the miniaturization of the structure, but also requires the pressure relief mechanism to be installed on the camshaft along with the sprocket, which is not conducive to improving assembly efficiency. Utility Model Content

[0004] Therefore, it is necessary to provide a pressure reduction mechanism, valve control structure, and engine that are not only compact in structure but also have high assembly efficiency to address the above problems.

[0005] The technical solution is as follows:

[0006] Firstly, a pressure-reducing mechanism is provided, comprising:

[0007] The support has a support hole for clearance fit with the camshaft. The outer peripheral surface of the support has a first protrusion with a through mounting hole for axially opposite to the pressure relief groove of the camshaft.

[0008] A pressure-reducing cam, wherein the pressure-reducing cam is rotatably disposed in the mounting hole, and one end of the pressure-reducing cam is rotatably inserted into the pressure-reducing groove;

[0009] A pressure-reducing rocker arm is disposed on one side of the support and is used to be set on the outer periphery of the camshaft. One end of the pressure-reducing rocker arm is rotatably connected to the support through a hinge pin, and the other end is driven to be connected to the other end of the pressure-reducing cam. The pressure-reducing cam can rotate relative to the support under the drive of the pressure-reducing rocker arm to lift or avoid the valve rocker arm.

[0010] A return spring, one end of which is connected to the support and the other end of which is connected to the pressure relief rocker arm, is used to apply tension to the side of the pressure relief rocker arm near the camshaft.

[0011] In the aforementioned pressure-reducing mechanism, a support is sleeved on the camshaft, and a pressure-reducing cam is rotatably inserted into the mounting hole of the support and the pressure-reducing groove of the camshaft. The pressure-reducing rocker arm is rotatably connected to the support and driven by the pressure-reducing cam. A return spring that can apply tension to the pressure-reducing rocker arm is connected between the pressure-reducing rocker arm and the support. This allows the pressure-reducing rocker arm to overcome the centrifugal force caused by the rotation of the camshaft under the elastic action of the return spring when the engine starts and the camshaft speed is relatively low. This prevents the pressure-reducing rocker arm from rotating and thus prevents it from driving the pressure-reducing cam to rotate. Consequently, the pressure-reducing cam can maintain the state of lifting the valve rocker arm in the engine to a certain height, even if the valve is slightly open, thereby reducing and controlling the pressure in the cylinder, reducing engine starting resistance, and making the engine start more easily and quickly. During the initial engine start-up, the camshaft speed gradually increases, which increases the centrifugal force on the decompression rocker arm. This causes the rocker arm to overcome the elastic force and swing, driving the decompression cam to rotate relative to the support and camshaft. At this time, the decompression cam still lifts the valve rocker arm, keeping the valve slightly open. Once the engine has started smoothly and the camshaft speed reaches a constant level, the decompression rocker arm is completely thrown off, and the decompression cam rotates to a position where it no longer lifts the valve rocker arm, closing the valve and completing the engine start-up. Therefore, this decompression mechanism effectively reduces compression resistance during engine start-up. Since the support is mounted on the camshaft, and the decompression cam, decompression rocker arm, and return spring are all mounted on the camshaft via the support, the decompression mechanism can be easily installed on the camshaft without the need for a sprocket. This not only facilitates structural miniaturization but also eliminates the need for online assembly of the decompression mechanism with a sprocket, thus shortening assembly time and improving assembly efficiency. Furthermore, since the support hole 12 of the support is clearance-fitted with the camshaft, the support can be easily fitted onto the camshaft, which also helps to further improve the assembly efficiency of the pressure reduction mechanism.

[0012] The technical solution will be further explained below:

[0013] In one embodiment, the support hole includes two first sidewalls, two second sidewalls, and four arcuate walls. The first sidewalls are planar, and the two first sidewalls are arranged opposite to each other. The first sidewalls are used to mate with the first plane of the camshaft. In the extending direction of the support hole, the projected length of the first sidewall is greater than the projected length of the first plane. The second sidewalls are arcuate, and the two second sidewalls are arranged opposite to each other and recessed in a direction away from each other. The second sidewalls are used to mate with the first arcuate surface of the camshaft. The arcuate walls connect adjacent first sidewalls and second sidewalls to form an oil injection groove communicating with the support hole.

[0014] In one embodiment, the first protrusion has a notch at one end opposite to the pressure relief rocker arm, and the notch penetrates the sidewall of the mounting hole.

[0015] In one embodiment, a reset post protrudes from the side of the support facing the pressure-reducing rocker arm. The reset post extends along the extension direction of the support hole. A connecting hole is opened at the end of the pressure-reducing rocker arm away from the pressure-reducing cam. The extension direction of the connecting hole is consistent with the extension direction of the reset post. The reset spring includes a first hook portion, an elastic portion, and a second hook portion connected in sequence. The first hook portion has a first opening and is engaged with the outer periphery of the reset post through the first opening. The second hook portion has a second opening and is engaged with the wall of the connecting hole through the second opening. The first opening and the second opening are not on the same plane.

[0016] In one embodiment, the first hook portion is arc-shaped, and the second hook portion includes a first straight rod, a second straight rod, and a third straight rod connected in sequence. The end of the first straight rod away from the second straight rod is connected to the elastic part. The first straight rod and the third straight rod are both set at an angle to the second straight rod. The first straight rod, the second straight rod, and the third straight rod together form the second opening. The first straight rod is located on the side of the pressure-reducing rocker arm away from the support. The second straight rod passes through the connecting hole. The third straight rod is located on the side of the pressure-reducing rocker arm away from the first straight rod.

[0017] In one embodiment, the decompression cam includes a shaft, a head, and a lifting boss. The head is disposed at one end of the shaft and on the side of the first protrusion near the decompression rocker arm. The outer diameter of the head is larger than the inner diameter of the mounting hole. The shaft passes through the mounting hole. The lifting boss is disposed at the end of the shaft away from the head. The lifting boss can be inserted into the decompression groove. The lifting boss has a lifting arc surface and a flat surface. The decompression cam has a lifting state and a yielding state. In the lifting state, the lifting arc surface can protrude out of the groove opening of the decompression groove to lift the valve rocker arm. In the yielding state, the flat surface can face the groove opening of the decompression groove and be received in the decompression groove. The decompression rocker arm can drive the decompression cam to switch from the lifting state to the yielding state.

[0018] In one embodiment, the head has a sliding groove extending radially along the shaft, and the pressure-reducing rocker arm has a drive pin protruding on the side facing the support. The end of the drive pin opposite to the pressure-reducing rocker arm is slidably inserted into the sliding groove. The drive pin can slide in the sliding groove under the drive of the pressure-reducing rocker arm and drive the pressure-reducing cam to rotate relative to the support.

[0019] In one embodiment, the pressure relief mechanism further includes a pressure relief baffle, which is disposed on the side of the pressure relief rocker arm away from the support and is used to be sleeved on the outer periphery of the camshaft. The side of the pressure relief baffle away from the pressure relief rocker arm is used to abut against the bearing.

[0020] Secondly, a valve control structure is provided, including a camshaft and the aforementioned decompression mechanism. An exhaust cam is provided on the camshaft, and a support is sleeved on the camshaft and located on one side of the exhaust cam. A decompression groove is formed on the outer peripheral surface of the exhaust cam. The decompression groove extends along the axial direction of the camshaft and penetrates the end face of the exhaust cam near the support. The decompression groove and the mounting hole are arranged opposite to each other in the axial direction of the camshaft. The decompression cam is rotatably inserted into the mounting hole and the decompression groove.

[0021] In the aforementioned valve control structure, both the support and the exhaust cam are mounted on the camshaft. The decompression cam is rotatably inserted into the mounting hole and decompression groove, while the decompression rocker arm is rotatably connected to the support and driven by the decompression cam. A return spring that can apply tension to the decompression rocker arm is connected between the decompression rocker arm and the support. Therefore, this valve control structure can effectively reduce the compression resistance during engine start-up. Since the support is fitted onto the camshaft, and the decompression cam, decompression rocker arm, and return spring are all mounted on the camshaft via the support, the decompression mechanism can be easily installed on the camshaft without the need for a sprocket. This not only facilitates structural miniaturization but also eliminates the need for online assembly of the decompression mechanism along with the sprocket, thereby shortening assembly time and improving assembly efficiency.

[0022] Thirdly, an engine is provided, including the valve control structure described above.

[0023] In the aforementioned engine, both the support and the exhaust cam are mounted on the camshaft. The decompression cam is rotatably inserted into the mounting hole and decompression groove, while the decompression rocker arm is rotatably connected to the support and driven by the decompression cam. A return spring that can apply tension to the decompression rocker arm is connected between the decompression rocker arm and the support. Therefore, this valve control structure can effectively reduce the compression resistance during engine start-up. Since the support is fitted onto the camshaft, and the decompression cam, decompression rocker arm, and return spring are all mounted on the camshaft via the support, the decompression mechanism can be easily installed on the camshaft without the need for a sprocket. This not only facilitates structural miniaturization but also eliminates the need for online assembly of the decompression mechanism along with the sprocket, thereby shortening assembly time and improving assembly efficiency. Attached Figure Description

[0024] Figure 1 This is a schematic diagram of the valve control structure in one embodiment.

[0025] Figure 2 for Figure 1 The diagram shows the exploded structure.

[0026] Figure 3 for Figure 1 A cross-sectional view of the structure shown.

[0027] Figure 4 for Figure 1 The diagram shows the structure from another perspective.

[0028] Figure 5 This is a schematic diagram of a pressure-reducing mechanism mounted on a camshaft in one embodiment.

[0029] Figure 6 This is a schematic diagram of the support structure in one embodiment.

[0030] Figure 7 This is a cross-sectional view of the support and camshaft in one embodiment.

[0031] Figure 8 This is a schematic diagram of the structure of the reset spring in one embodiment.

[0032] Figure 9 This is a schematic diagram of the decompression cam in one embodiment.

[0033] Explanation of reference numerals in the attached figures:

[0034] 10. Valve control structure; 100. Pressure reducing mechanism; 1. Support; 11. First protrusion; 111. Mounting hole; 112. Notch; 12. Support hole; 121. First side wall; 122. Arc-shaped wall; 123. Second side wall; 13. Oil filling groove; 14. Reset column; 141. Second protrusion; 15. Hinge pin; 151. Third protrusion; 2. Pressure reducing cam; 21. Head; 211. Sliding groove; 22. Shaft; 23. Lifting boss; 231. Flat 232. Lifting arc surface; 3. Pressure reducing rocker arm; 31. Connecting hole; 32. Drive pin; 4. Return spring; 41. First hook part; 42. Elastic part; 43. Second hook part; 431. First straight rod; 432. Second straight rod; 433. Third straight rod; 5. Pressure reducing baffle; 200. Camshaft; 200a. First plane; 200b. First arc surface; 201. Exhaust cam; 202. Pressure reducing groove; 203. Bearing; 204. Flange. Detailed Implementation

[0035] To make the above-mentioned objectives, features, and advantages of this application more apparent and understandable, the specific embodiments of this application are described in detail below with reference to the accompanying drawings. Many specific details are set forth in the following description to provide a thorough understanding of this application. However, this application can be implemented in many other ways different from those described herein, and those skilled in the art can make similar modifications without departing from the spirit of this application. Therefore, this application is not limited to the specific embodiments disclosed below.

[0036] In the description of this application, it should be understood that if terms such as "center", "longitudinal", "lateral", "length", "width", "thickness", "upper", "lower", "front", "rear", "left", "right", "vertical", "horizontal", "top", "bottom", "inner", "outer", "clockwise", "counterclockwise", "axial", "radial", "circumferential" appear, these terms indicate the orientation or positional relationship based on the orientation or positional relationship shown in the accompanying drawings, and are only for the convenience of describing this application and simplifying the description, and do not indicate or imply that the device or element referred to must have a specific orientation, or be constructed and operated in a specific orientation, and therefore should not be construed as a limitation of this application.

[0037] Furthermore, where the terms "first" and "second" appear, these terms are for descriptive purposes only and should not be construed as indicating or implying relative importance or implicitly specifying the number of technical features indicated. Thus, a feature defined with "first" or "second" may explicitly or implicitly include at least one of that feature. In the description of this application, where the term "multiple" appears, "multiple" means at least two, such as two, three, etc., unless otherwise explicitly specified.

[0038] In this application, unless otherwise expressly specified and limited, the terms "installation," "connection," "joining," and "fixing," etc., should be interpreted broadly. For example, they can refer to a fixed connection, a detachable connection, or an integral part; they can refer to a mechanical connection or an electrical connection; they can refer to a direct connection or an indirect connection through an intermediate medium; they can refer to the internal communication of two components or the interaction between two components, unless otherwise expressly limited. Those skilled in the art can understand the specific meaning of the above terms in this application based on the specific circumstances.

[0039] In this application, unless otherwise expressly specified and limited, the use of descriptions such as "above" or "below" the second feature indicates that the first and second features are in direct contact or indirect contact via an intermediate medium. Furthermore, "above," "on top of," and "over" the second feature can mean that the first feature is directly above or diagonally above the second feature, or simply that the first feature is at a higher horizontal level than the second feature. Similarly, "below," "below," and "under" the second feature can mean that the first feature is directly below or diagonally below the second feature, or simply that the first feature is at a lower horizontal level than the second feature.

[0040] It should be noted that if an element is referred to as being "fixed to" or "set on" another element, it can be directly on the other element or there may be an intervening element. If an element is considered to be "connected to" another element, it can be directly connected to the other element or there may be an intervening element. If so, the terms "vertical," "horizontal," "upper," "lower," "left," "right," and similar expressions used in this application are for illustrative purposes only and do not represent the only possible implementation.

[0041] See Figures 1 to 5 An embodiment of this application provides a pressure-reducing mechanism 100, including a support 1, a pressure-reducing cam 2, a pressure-reducing rocker arm 3, and a return spring 4. Wherein:

[0042] The support 1 has a support hole 12 for clearance fitting with the camshaft 200. A first protrusion 11 protrudes from the outer circumference of the support 1, and a through mounting hole 111 is formed on the first protrusion 11. The mounting hole 111 is axially opposite to the decompression groove 202 of the camshaft 200. The decompression cam 2 is rotatably inserted through the mounting hole 111, and one end of the decompression cam 2 is rotatably inserted into the decompression groove 202. A decompression rocker arm 3 is located on one side of the support 1 and is positioned on the outer circumference of the camshaft 200. One end of the decompression rocker arm 3 is rotatably connected to the support 1 via a hinge pin 15, and the other end is drivenly connected to the other end of the decompression cam 2. The decompression cam 2 can rotate relative to the support 1 under the drive of the decompression rocker arm 3 to lift or avoid the valve rocker arm. One end of a return spring 4 is connected to the support 1, and the other end is connected to the decompression rocker arm 3. The return spring 4 applies tension to the side of the decompression rocker arm 3 closest to the camshaft 200.

[0043] In the aforementioned pressure-reducing mechanism 100, the support 1 is sleeved on the camshaft 200, the pressure-reducing cam 2 is rotatably inserted into the mounting hole 111 of the support 1 and the pressure-reducing groove 202 of the camshaft 200, and the pressure-reducing rocker arm 3 is rotatably connected to the support 1 and driven by the pressure-reducing cam 2. A return spring 4 that can apply tension to the pressure-reducing rocker arm 3 is connected between the pressure-reducing rocker arm 3 and the support 1. This allows the pressure-reducing rocker arm 3 to overcome the centrifugal force caused by the rotation of the camshaft 200 under the elastic action of the return spring 4 when the engine starts and the rotation speed of the camshaft 200 is relatively low, so that the pressure-reducing rocker arm 3 does not rotate and does not drive the pressure-reducing cam 2 to rotate. This allows the pressure-reducing cam 2 to maintain the state of lifting the valve rocker arm in the engine to a certain height, even if the valve is slightly open, so as to reduce and control the pressure in the cylinder, reduce the engine starting resistance, and make the engine start more easily and quickly. During the initial engine start-up, the camshaft 200 gradually increases in speed, which increases the centrifugal force on the decompression rocker arm 3. This allows the rocker arm 3 to overcome the elastic force and swing, driving the decompression cam 2 to rotate relative to the support 1 and the camshaft 200. At this time, the decompression cam 2 can still lift the valve rocker arm, keeping the valve in a slightly open state. Once the engine starts smoothly and the camshaft 200 reaches a constant speed, the decompression rocker arm 3 is completely thrown off, and the decompression cam 2 rotates to a position where it no longer lifts the valve rocker arm, closing the valve and completing the engine start-up. Therefore, this decompression mechanism 100 effectively reduces the compression resistance during engine start-up. Since the support 1 is fitted onto the camshaft 200, and the pressure-reducing cam 2, pressure-reducing rocker arm 3, and return spring 4 are all mounted on the camshaft 200 via the support 1, the pressure-reducing mechanism 100 can be easily installed onto the camshaft 200 without the aid of a sprocket. This not only facilitates structural miniaturization but also eliminates the need for the pressure-reducing mechanism 100 to be assembled online with the sprocket, thereby shortening assembly time and improving assembly efficiency. Furthermore, because the support hole 12 of the support 1 has a clearance fit with the camshaft 200, the support 1 can be easily fitted onto the camshaft 200, which further enhances the assembly efficiency of the pressure-reducing mechanism 100. In addition, when the engine stops running, the pressure-reducing rocker arm 3 can return to its original position under the tension of the return spring 4, ensuring the reliability of the pressure-reducing mechanism 100.

[0044] Specifically, an exhaust cam 201 is provided on the camshaft 200, and the exhaust cam 201 rotates synchronously with the camshaft 200. A support 1 is fitted onto the camshaft 200 and is arranged adjacent to the exhaust cam 201. A pressure-reducing groove 202 is formed on the outer peripheral surface of the exhaust cam 201, and one end of the pressure-reducing groove 202 penetrates the end face of the exhaust cam 201 near the support 1, so that when the pressure-reducing cam 2 is installed in the mounting hole 111, one end of the pressure-reducing cam 2 can be inserted into the pressure-reducing groove 202. Schematic, the pressure-reducing groove 202 is located at the lowest point of the exhaust cam 201. When starting the engine, the surface of the pressure-reducing cam 2 can be higher than the outer contour of the lowest point of the exhaust cam 201 to press against the valve rocker arm, causing the valve to open to a certain position to appropriately reduce the air pressure in the cylinder, reduce engine starting resistance, and make the engine start more easily and quickly. When the engine is running smoothly, the decompression cam 2 can rotate under the drive of the decompression rocker arm 3 to a position where its surface is lower than the outer contour of the exhaust cam 201, so that the decompression cam 2 no longer pushes up the valve rocker arm, the valve closes, and the engine runs normally.

[0045] Schematic illustration: A hinge hole is provided on the side of the support 1 near the pressure-reducing rocker arm 3, and a hinge pin 15 is fixedly inserted into the hinge hole. Further, a third protrusion 151 is provided on the end face of the support 1 near the pressure-reducing rocker arm 3, and the hinge hole passes through the third protrusion, so that when the hinge pin 15 is inserted into the hinge hole, the hinge pin 15 has sufficient fixing length to ensure that the hinge pin 15 can be stably set on the support 1.

[0046] In one embodiment, such as Figure 6 and Figure 7As shown, the support hole 12 includes two first sidewalls 121, two second sidewalls 123, and four arcuate walls 122. The first sidewalls 121 are planar, and the two first sidewalls 121 are arranged opposite to each other. The first sidewalls 121 are used to cooperate with the first plane 200a of the camshaft 200. In the extension direction of the support hole 12, the projected length of the first sidewall 121 is greater than the projected length of the first plane 200a. The second sidewalls 123 are arcuate, and the two second sidewalls 123 are arranged opposite to each other and recessed in a direction away from each other. The second sidewalls 123 are used to cooperate with the first arcuate surface 200b of the camshaft 200. The arcuate walls 122 are connected between adjacent first sidewalls 121 and second sidewalls 123 to form an oil filling groove 13 that communicates with the support hole 12. Thus, the support 1 can be reliably fitted onto the camshaft 200 through the engagement of the first sidewall 121 with the first plane 200a and the engagement of the second sidewall 123 with the first arc surface 200b. Since the projected length of the first sidewall 121 is greater than the projected length of the first plane 200a in the extending direction of the support hole 12, the support 1's sway during camshaft 200 rotation can be reduced by ensuring a larger contact area between the first sidewall 121 and the first plane 200a, thereby ensuring the stability of the pressure-reducing mechanism 100, provided that the support hole 121 and the camshaft 200 are in a clearance fit. In addition, since the arc-shaped wall 122 is connected between the adjacent first side wall 121 and second side wall 123, the four arc-shaped walls 122 can form four oil injection grooves 13 at intervals on the side wall of the support hole 12. This allows lubricating oil to be injected between the support 1 and the camshaft 200 through the oil injection grooves 13, thereby reducing the friction between the support 1 and the camshaft 200, avoiding wear on the inner wall of the support hole 12, and improving the service life of the pressure reducing mechanism 100.

[0047] Schematic illustration: along the axial direction of the camshaft 200, the first arcuate surface 200b and the second sidewall 123 are coaxially arranged. Thus, the sway of the support 1 can be reduced through the engagement between the first arcuate surface 200b and the second sidewall 123. Further, the journal portion of the camshaft 200 used to mount the support 1 may include two first planes 200a and two first arcuate surfaces 200b, wherein the two first planes 200a are arranged opposite to each other, and the two first arcuate surfaces 200b are disposed between the two first planes 200a. The two first arcuate surfaces 200b have an outwardly convex arcuate structure.

[0048] Optionally, in one embodiment, such as Figure 4 and Figure 6As shown, the first protrusion 11 has a notch 112 at the end opposite to the pressure-reducing rocker arm 3, and the notch 112 penetrates the side wall of the mounting hole 111. Thus, the notch 112 allows the mounting hole 111 to be configured as a semi-open shaft hole including an annular section and a connecting groove section. This ensures that when the pressure-reducing cam 2 is installed in the mounting hole 111, the side wall of the annular section can confine the pressure-reducing cam 2 within the mounting hole 111, preventing the pressure-reducing cam 2 from falling out of the mounting hole 111, ensuring the stability of the pressure-reducing cam 2 during rotation, and the reliability of the pressure-reducing mechanism 100. The connecting groove section allows part of the pressure-reducing cam 2 to be exposed outside the first protrusion 11, allowing lubricant to be injected into the pressure-reducing cam 2 through the notch 112, ensuring lubrication between the pressure-reducing cam 2 and the wall of the mounting hole 111, and reducing wear during rotation of the pressure-reducing cam 2.

[0049] In one embodiment, such as Figure 5 and Figure 6 As shown, a reset post 14 protrudes from the side of the support 1 facing the pressure reducing rocker arm 3. The reset post 14 extends along the extension direction of the support hole 12. A connecting hole 31 is opened at the end of the pressure reducing rocker arm 3 away from the pressure reducing cam 2. The extension direction of the connecting hole 31 is consistent with the extension direction of the reset post 14. The reset spring 4 includes a first hook part 41, an elastic part 42 and a second hook part 43 connected in sequence. The first hook part 41 has a first opening and is engaged with the outer periphery of the reset post 14 through the first opening. The second hook part 43 has a second opening and is engaged with the wall of the connecting hole 31 through the second opening. The first opening and the second opening are not on the same plane. Since the extension direction of the connecting hole 31 is consistent with the extension direction of the reset post 14, when the first hook part 41 is connected to the reset post 14 and the second hook part 43 is connected to the connecting hole 31, the opening of the first hook part 41 and the opening of the second hook part 43 are not in the same plane. As a result, when the reset spring 4 is connected between the support 1 and the pressure reducing rocker arm 3, the reset post 14 can restrict the second hook part 43 from rotating in the circumferential direction of the connecting hole 31, and the side wall of the connecting hole 31 can restrict the first hook part 41 from sliding along the axial direction of the reset post 14. This prevents the elastic part 42 from contacting other structures, such as the camshaft 200 or the support 1, due to slippage, thus avoiding wear of the reset spring 4.

[0050] Schematic illustration: the reset pin 14 can be a pin, and the support 1 has a pin hole extending along the extension direction of the support hole 12. The reset pin 14 is inserted into the pin hole. Furthermore, in order to ensure that the reset pin 14 can be reliably inserted into the pin hole, a second protrusion 141 is provided on the end face of the support 1 near the pressure reducing rocker arm 3. The pin hole passes through the second protrusion 141, so that when the reset pin 14 is inserted into the pin hole, the reset pin 14 has sufficient fixed length to ensure that the reset pin 14 can be stably set on the support 1.

[0051] For illustration purposes, the return spring 4 is a tension spring.

[0052] Optionally, in one embodiment, such as Figure 8 As shown, the first hook portion 41 is curved in an arc shape, and the second hook portion 43 includes a first straight rod 431, a second straight rod 432, and a third straight rod 433 connected in sequence. The end of the first straight rod 431 facing away from the second straight rod 432 is connected to the elastic part 42. The first straight rod 431 and the third straight rod 433 are both set at an angle to the second straight rod 432. The first straight rod 431, the second straight rod 432, and the third straight rod 433 together form a second opening. The first straight rod 431 is located on the side of the pressure-reducing rocker arm 3 facing away from the support 1. The second straight rod 432 passes through the connecting hole 31, and the third straight rod 433 is located on the side of the pressure-reducing rocker arm 3 facing away from the first straight rod 431. In this way, when assembling the return spring 4, the first hook portion 41 and the second hook portion 43 can be easily identified by their shapes, so as to avoid incorrect installation of the return spring 4. Since the first straight rod 431 and the third straight rod 433 in the second hook part 43 are both set at an angle to the second straight rod 432, and the first straight rod 431 and the third straight rod 433 are respectively located on both sides of the connecting hole 31, when the second hook part 43 is connected to the connecting hole 31, the third straight rod 433 can restrict the sliding of the second hook part 43 relative to the pressure relief rocker arm 3 by abutting against the ground at the opening edge of the connecting hole 31, thereby ensuring the stability of the return spring 4 during operation and avoiding wear of the elastic part 42 due to slippage.

[0053] In one embodiment, such as Figure 3 , Figure 4 and Figure 9As shown, the decompression cam 2 includes a shaft portion 22, a head portion 21, and a lifting boss 23. The head portion 21 is located at one end of the shaft portion 22 and is located on the side of the first protrusion 11 near the decompression rocker arm 3. The outer diameter of the head portion 21 is larger than the inner diameter of the mounting hole 111. The shaft portion 22 passes through the mounting hole 111. The lifting boss 23 is located at the end of the shaft portion 22 away from the head portion 21. The lifting boss 23 can be inserted into the decompression groove 202. The decompression cam 2 has a lifting state and a yielding state. In the lifting state, the lifting boss 23 is used to lift the valve rocker arm. In the yielding state, the lifting boss 23 can be separated from the valve rocker arm, and the decompression rocker arm 3 can drive the decompression cam 2 to switch from the lifting state to the yielding state. Thus, when the pressure-reducing cam 2 is installed in the mounting hole 111, the head 21 can restrict the axial movement of the pressure-reducing cam 2 in the camshaft 200 by abutting against the edge of the opening at the end of the mounting hole 111 facing the pressure-reducing rocker arm 3, thereby ensuring the stability of the pressure-reducing cam 2 and ensuring that the pressure-reducing cam 2 can be reliably driven to connect with the pressure-reducing rocker arm 3. In addition, since the lifting boss 23 is inserted into the pressure-reducing groove 202, when the pressure-reducing rocker arm 3 rotates under the action of centrifugal force, the lifting boss 23 can rotate within the pressure-reducing groove 202, thereby allowing the lifting boss 23 to lift or avoid the valve rocker arm. Specifically, when the engine starts, the pressure-reducing cam 2 is in the lifted state, and the lifting boss 23 can lift the valve rocker arm in the engine to a certain height, so that the valve is in a slightly open state, thereby reducing the pressure in the cylinder and reducing the engine starting energy consumption. When the camshaft 200 speed increases, the lifting boss 23 can rotate relative to the camshaft 200 under the action of the decompression rocker arm 3. When the speed of the camshaft 200 is at a certain constant speed, the lifting boss 23 can rotate under the action of the decompression rocker arm 3 to the position where the valve rocker arm does not contact, thus achieving the effect of avoiding the valve rocker arm. The decompression cam 2 enters the avoidance state so that the valve closes and the engine starts.

[0054] Furthermore, combined Figure 3 , Figure 4 and Figure 9As shown, the lifting boss 23 has a flat surface 231 and a lifting arc surface 232. In the lifting state, the lifting arc surface 232 can protrude from the opening of the decompression groove 202 to lift the valve rocker arm. In the yielding state, the flat surface 231 can face the opening of the decompression groove 202 and be received within the decompression groove 202. Thus, during engine starting, when the decompression cam 2 is in the lifting state, the lifting arc surface 232 can be higher than the opening of the decompression groove 202. Therefore, the decompression cam 2 can control the valve to a slightly open state through the contact between the lifting arc surface 232 and the valve rocker arm to reduce the resistance of engine starting. When the decompression cam 2 rotates to the avoidance state under the drive of the decompression rocker arm 3, since the flat surface 231 faces the opening of the decompression groove 202 and is contained within the decompression groove 202, the flat surface 231 does not protrude from the opening of the decompression groove 202. This allows the decompression cam 2 to avoid contact with the valve rocker arm, thus achieving the effect of avoiding the valve rocker arm. As a result, when the camshaft 200 rotates, the flat surface 231 can not interfere with the normal operation of the valve rocker arm, that is, the valve can enter the fully closed state to ensure that the engine can rotate smoothly.

[0055] Optionally, in one embodiment, combining Figure 3 and Figure 9 As shown, the head 21 has a sliding groove 211 extending radially along the shaft 22. A drive pin 32 protrudes from the side of the pressure-reducing rocker arm 3 facing the support 1. The end of the drive pin 32 facing away from the pressure-reducing rocker arm 3 is slidably inserted into the sliding groove 211. The drive pin 32 can slide within the sliding groove 211 under the drive of the pressure-reducing rocker arm 3, and drive the pressure-reducing cam 2 to rotate relative to the support 1. Thus, when the engine starts and the camshaft 200 rotates and the pressure-reducing rocker arm 3 swings under centrifugal force, the pressure-reducing rocker arm 3 can drive the drive pin 32 to slide within the sliding groove 211, and drive the drive pin to rotate the pressure-reducing cam 2 relative to the support 1 by a certain angle. This allows the pressure-reducing cam 2 to rotate from the position where it lifts the engine's exhaust rocker arm to a position where the exhaust rocker arm is no longer in contact, thereby closing the exhaust valve and ensuring stable engine operation. When the engine stops, the pressure-reducing rocker arm 3 can, under the return action of the return spring 4, drive the drive pin 32 to slide relative to the sliding groove 211 to reset the pressure-reducing rocker arm 3.

[0056] In one embodiment, such as Figures 1 to 4As shown, the pressure-reducing mechanism 100 also includes a pressure-reducing baffle 5, which is located on the side of the pressure-reducing rocker arm 3 away from the support 1 and is used to be sleeved on the outer periphery of the camshaft 200. Thus, when the pressure-reducing mechanism 100 is installed on the camshaft 200, the pressure-reducing baffle 5 can be positioned between the pressure-reducing rocker arm 3 and the bearing 203 located on the camshaft 200, allowing the baffle to press against the pressure-reducing rocker arm 3 axially on the camshaft 200 under the action of the bearing 203, thereby limiting the axial movement of the pressure-reducing rocker arm 3 and ensuring the stability of the pressure-reducing mechanism 100.

[0057] Indicatively, a flange 204 is provided on the side of the bearing 203 away from the pressure relief baffle 5. The flange 204 is fixed on the camshaft 200. In this way, the flange 204 can reliably fix the bearing 203 on the camshaft 200, so that the pressure relief baffle 5 can limit the movement of the pressure relief rocker arm 3 in the axial direction of the camshaft 200 under the action of the bearing 203.

[0058] like Figures 1 to 4 As shown, one embodiment of this application also provides a valve control structure 10, including a camshaft 200 and a decompression mechanism 100 of any of the above embodiments. An exhaust cam 201 is provided on the camshaft 200. A support 1 is sleeved on the camshaft 200 and provided on one side of the exhaust cam 201. A decompression groove 202 is provided on the outer peripheral surface of the exhaust cam 201. The decompression groove 202 extends along the axial direction of the camshaft 200 and passes through the end face of the exhaust cam 201 near the support 1. The decompression groove 202 and the mounting hole 111 are arranged opposite to each other in the axial direction of the camshaft 200. The decompression cam 2 is rotatably inserted into the mounting hole 111 and the decompression groove 202.

[0059] In the valve control structure 10 described above, the support 1 and the exhaust cam 201 are both located on the camshaft 200. The decompression cam 2 is rotatably inserted into the mounting hole 111 and the decompression groove 202. The decompression rocker arm 3 is rotatably connected to the support 1 and driven by the decompression cam 2. A return spring 4 that can apply tension to the decompression rocker arm 3 is connected between the decompression rocker arm 3 and the support 1. Therefore, this valve control structure 10 can effectively reduce the compression resistance during engine start-up. Since the support 1 is sleeved on the camshaft 200, and the decompression cam 2, decompression rocker arm 3, and return spring 4 are all mounted on the camshaft 200 through the support 1, the decompression mechanism 100 can be conveniently installed on the camshaft 200 without the aid of a sprocket. This not only facilitates the miniaturization of the structure but also eliminates the need for the decompression mechanism 100 to be assembled online with the sprocket, thereby shortening the assembly time and improving assembly efficiency.

[0060] One embodiment of this application also provides an engine including the valve control structure 10 described above.

[0061] In the aforementioned engine, both the support 1 and the exhaust cam 201 are mounted on the camshaft 200. The decompression cam 2 is rotatably inserted into the mounting hole 111 and the decompression groove 202. The decompression rocker arm 3 is rotatably connected to the support 1 and driven by the decompression cam 2. A return spring 4, which can apply tension to the decompression rocker arm 3, is connected between the decompression rocker arm 3 and the support 1. Therefore, this valve control structure 10 can effectively reduce the compression resistance during engine startup. Since the support 1 is mounted on the camshaft 200, and the decompression cam 2, decompression rocker arm 3, and return spring 4 are all mounted on the camshaft 200 via the support 1, the decompression mechanism 100 can be conveniently installed on the camshaft 200 without the aid of a sprocket. This not only facilitates the miniaturization of the structure but also eliminates the need for the decompression mechanism 100 to be assembled online with the sprocket, thereby shortening assembly time and improving assembly efficiency.

[0062] The technical features of the above embodiments can be combined in any way. For the sake of brevity, not all possible combinations of the technical features in the above embodiments are described. However, as long as there is no contradiction in the combination of these technical features, they should be considered to be within the scope of this specification.

[0063] The above embodiments merely illustrate several implementation methods of this application, and while the descriptions are relatively specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of this application, and these all fall within the protection scope of this application. Therefore, the protection scope of this patent application should be determined by the appended claims.

Claims

1. A pressure-reducing mechanism, characterized in that, include: The support has a support hole for clearance fit with the camshaft. The outer peripheral surface of the support has a first protrusion with a through mounting hole for axially opposite to the pressure relief groove of the camshaft. A pressure-reducing cam, wherein the pressure-reducing cam is rotatably disposed in the mounting hole, and one end of the pressure-reducing cam is rotatably inserted into the pressure-reducing groove; A pressure-reducing rocker arm is disposed on one side of the support and is used to be set on the outer periphery of the camshaft. One end of the pressure-reducing rocker arm is rotatably connected to the support through a hinge pin, and the other end is driven to be connected to the other end of the pressure-reducing cam. The pressure-reducing cam can rotate relative to the support under the drive of the pressure-reducing rocker arm to lift or avoid the valve rocker arm. A return spring, one end of which is connected to the support and the other end of which is connected to the pressure relief rocker arm, is used to apply tension to the side of the pressure relief rocker arm near the camshaft.

2. The pressure-reducing mechanism according to claim 1, characterized in that, The support hole includes two first sidewalls, two second sidewalls, and four arc-shaped walls. The first sidewalls are planar, and the two first sidewalls are arranged opposite to each other. The first sidewalls are used to mate with the first plane of the camshaft. In the extension direction of the support hole, the projected length of the first sidewall is greater than the projected length of the first plane. The second sidewalls are arc-shaped, and the two second sidewalls are arranged opposite to each other and recessed in a direction away from each other. The second sidewalls are used to mate with the first arc surface of the camshaft. The arc-shaped walls connect adjacent first sidewalls and second sidewalls to form an oil injection groove communicating with the support hole.

3. The pressure-reducing mechanism according to claim 1, characterized in that, The first protrusion has a notch at one end opposite to the pressure relief rocker arm, and the notch penetrates the side wall of the mounting hole.

4. The pressure-reducing mechanism according to claim 1, characterized in that, The support has a resetting post protruding from one side facing the pressure-reducing rocker arm. The resetting post extends along the extension direction of the support hole. The end of the pressure-reducing rocker arm opposite to the pressure-reducing cam has a connecting hole. The extension direction of the connecting hole is consistent with the extension direction of the resetting post. The resetting spring includes a first hook part, an elastic part, and a second hook part connected in sequence. The first hook part has a first opening and is engaged with the outer periphery of the resetting post through the first opening. The second hook part has a second opening and is engaged with the wall of the connecting hole through the second opening. The first opening and the second opening are not on the same plane.

5. The pressure-reducing mechanism according to claim 4, characterized in that, The first hook part is curved in an arc shape. The second hook part includes a first straight rod, a second straight rod, and a third straight rod connected in sequence. The end of the first straight rod away from the second straight rod is connected to the elastic part. The first straight rod and the third straight rod are both set at an angle to the second straight rod. The first straight rod, the second straight rod, and the third straight rod together form the second opening. The first straight rod is located on the side of the pressure-reducing rocker arm away from the support. The second straight rod passes through the connecting hole. The third straight rod is located on the side of the pressure-reducing rocker arm away from the first straight rod.

6. The pressure-reducing mechanism according to claim 1, characterized in that, The decompression cam includes a shaft, a head, and a lifting boss. The head is located at one end of the shaft and on the side of the first protrusion near the decompression rocker arm. The outer diameter of the head is larger than the inner diameter of the mounting hole. The shaft passes through the mounting hole. The lifting boss is located at the end of the shaft away from the head and can be inserted into the decompression groove. The lifting boss has a lifting arc surface and a flat surface. The decompression cam has a lifting state and a yielding state. In the lifting state, the lifting arc surface can protrude out of the groove opening of the decompression groove to lift the valve rocker arm. In the yielding state, the flat surface can face the groove opening of the decompression groove and be received in the decompression groove. The decompression rocker arm can drive the decompression cam to switch from the lifting state to the yielding state.

7. The pressure-reducing mechanism according to claim 6, characterized in that, The head has a sliding groove extending radially along the shaft. The pressure-reducing rocker arm has a drive pin protruding on the side facing the support. The end of the drive pin opposite to the pressure-reducing rocker arm is slidably inserted into the sliding groove. The drive pin can slide in the sliding groove under the drive of the pressure-reducing rocker arm and drive the pressure-reducing cam to rotate relative to the support.

8. The pressure-reducing mechanism according to claim 1, characterized in that, The pressure relief mechanism further includes a pressure relief baffle, which is located on the side of the pressure relief rocker arm away from the support and is used to be sleeved on the outer periphery of the camshaft. The side of the pressure relief baffle away from the pressure relief rocker arm is used to abut against the bearing.

9. A valve control structure, characterized in that, The device includes a camshaft and a pressure-reducing mechanism as described in any one of claims 1 to 8. The camshaft is provided with an exhaust cam. The support is sleeved on the camshaft and located on one side of the exhaust cam. A pressure-reducing groove is formed on the outer peripheral surface of the exhaust cam. The pressure-reducing groove extends along the axial direction of the camshaft and penetrates the end face of the exhaust cam near the support. The pressure-reducing groove and the mounting hole are arranged opposite to each other in the axial direction of the camshaft. The pressure-reducing cam is rotatably inserted into the mounting hole and the pressure-reducing groove.

10. An engine, characterized in that, Includes the valve control structure as described in claim 9.

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