Starting pressure reduction mechanism and engine

Abstract

The utility model discloses a starting pressure reducing mechanism and an engine, the starting pressure reducing mechanism comprises a cam shaft, a chain wheel, a lifting pin, a flail block and a spring, and the cam shaft is provided with an exhaust cam; the sprocket is used for driving the camshaft to rotate; the lifting pin can protrude out of and be recessed into the base circle face of the exhaust cam. The flail block swings along the hinged center of the flail block and the chain wheel under the action of centrifugal force so as to drive the lifting pin to be recessed into the base circular surface of the exhaust cam; the springs are used for driving the flail blocks to reset so that the flail blocks drive the lifting pins to protrude out of the base circle surface of the exhaust cam; one of the flail block and the chain wheel is provided with a first pin, the other one of the flail block and the chain wheel is provided with an arc-shaped groove, and the first pin and the arc-shaped groove are matched for guiding and limiting. According to the starting pressure reduction mechanism, the swinging path of the swinging block can be guided, the maximum swinging stroke of the swinging block can be limited, it is guaranteed that the position of the lifting pin is stable, and the effect of the starting pressure reduction mechanism is guaranteed.

Description

Technical Field

[0001] This utility model relates to the technical field of engine structure, and in particular to a starting decompression mechanism and an engine. Background Technology

[0002] When a motorcycle engine starts, it needs to draw in new gas for compression. Near the end of the compression, a large amount of compression resistance is generated, making starting very difficult. In order to ensure that the engine can start smoothly, a pressure reduction structure is usually used to reduce pressure.

[0003] Typically, the starting pressure relief mechanism includes a camshaft, sprocket, sling block, spring, and top pin. The sling block is hinged to the sprocket and is used to drive the top pin to protrude from or recess into the base circle surface of the camshaft. The spring is used to drive the sling block to keep the top pin protruding from the base circle surface of the camshaft, so that the top pin can drive the exhaust valve to open slightly to release pressure. When the sprocket rotates to a certain speed, the sling block is radially swung by centrifugal force to overcome the elastic force of the spring and drive the top pin to recess into the base circle surface of the camshaft, so that the starting pressure relief mechanism stops releasing pressure.

[0004] However, the swing stroke of the existing starting pressure reducing mechanism is unstable, which can easily lead to an unstable position of the top pin and affect the effectiveness of the starting pressure reducing mechanism. Utility Model Content

[0005] This invention aims to solve at least one of the technical problems existing in the prior art. To this end, this invention proposes a decompression mechanism that guides the swing path of the swing block and limits its maximum swing stroke, ensuring the stability of the top pin and guaranteeing the effectiveness of the decompression mechanism.

[0006] This utility model also proposes an engine having the above-mentioned starting and decompression mechanism.

[0007] A pressure-reducing mechanism according to a first aspect of the present invention includes:

[0008] Camshaft, with exhaust cam;

[0009] The sprocket meshes with the engine's timing chain and is used to drive the camshaft to rotate;

[0010] A top pin is movably mounted on the exhaust cam and can protrude from and retract into the base circle surface of the exhaust cam;

[0011] A swing block is hinged to the sprocket. Under the action of centrifugal force, the swing block swings along the hinge center between the swing block and the sprocket to drive the top pin to be recessed into the base circle surface of the exhaust cam.

[0012] A spring is used to drive the throwing block to reset so that the throwing block drives the top pin to protrude from the base circle surface of the exhaust cam;

[0013] One of the sling block and the sprocket is provided with a first pin, and the other of the sling block and the sprocket is provided with an arc-shaped groove extending circumferentially along the hinge center of the sling block and the sprocket. The first pin cooperates with the arc-shaped groove for guidance and limitation.

[0014] A pressure-reducing mechanism according to an embodiment of the present invention has at least the following beneficial effects:

[0015] 1. This utility model movably sets a top pin on the exhaust cam. The top pin can protrude from and be recessed into the base circle surface of the exhaust cam. It can be understood that when the top pin protrudes from the base circle surface of the exhaust cam and the base circle surface of the exhaust cam abuts against the valve top sleeve, the internal combustion engine is in the compression process. At this time, the top pin can lift the valve top sleeve, realize the slight opening of the exhaust valve, release the gas pressure in the original sealed combustion chamber of the internal combustion engine, achieve the purpose of decompression, and effectively improve the problem of high engine starting resistance and difficulty in starting caused by excessive starting cylinder pressure.

[0016] 2. This utility model incorporates a swing block hinged to a sprocket. Under centrifugal force, the swing block oscillates along the hinge center between the swing block and the sprocket, causing the top pin to be recessed into the base circle surface of the exhaust cam. It can be understood that when the engine starts, the sprocket begins to rotate. Once the sprocket reaches a certain speed, i.e., when the engine is running normally after starting, the centrifugal force on the swing block can drive it to oscillate along the hinge center between the swing block and the sprocket. This allows the swing block to cause the top pin to be recessed into the base circle surface of the exhaust cam, thus rendering the pressure-reducing effect of the starting pressure-reducing mechanism ineffective during normal engine operation and preventing pressure leakage during normal engine operation.

[0017] 3. This utility model incorporates a spring that drives the sling block to reset, causing the sling block to cause the top pin to protrude from the base circle surface of the exhaust cam. It is understood that after the engine is turned off, the sprocket speed gradually decreases until it stops rotating, and the centrifugal force on the sling block also gradually decreases until it reaches zero. At this time, the spring can drive the sling block to reset, causing the sling block to cause the top pin to protrude from the base circle surface of the exhaust cam. Therefore, the starting decompression mechanism can restore its decompression function after the engine is turned off, and thus, when the engine is started again, the starting decompression mechanism can achieve its decompression function.

[0018] 4. This utility model features a first pin in one of the swing block and the sprocket, and an arc-shaped groove extending circumferentially along the hinge center between the swing block and the sprocket in the other. The first pin engages with the arc-shaped groove for guidance and limiting. This means that the swing stroke range of the swing block is precisely limited by the engagement of the first pin and the arc-shaped groove, preventing excessive displacement due to centrifugal force. This ensures stable and reliable protrusion / recession of the top pin. Simultaneously, the engagement of the arc-shaped groove with the first pin guides the swing path of the swing block and limits its maximum swing stroke, ensuring the stability of the top pin's position and guaranteeing the effectiveness of the pressure-reducing mechanism. This structure effectively solves the problem of top pin position fluctuation caused by unstable swing block stroke in traditional designs, significantly improving the consistency of the pressure-reducing mechanism's operation.

[0019] According to some embodiments of the present invention, the swing block and the sprocket are hinged by a first rivet, the spring is set as a torsion spring, the torsion spring is fitted on the first rivet, one end of the torsion spring is connected to the swing block, and the other end of the torsion spring is connected to the sprocket.

[0020] The advantages of this invention are: by hinged the swing block and the sprocket together through the first rivet, and setting the spring as a torsion spring, with the torsion spring fitted onto the first rivet, one end of the torsion spring connected to the swing block and the other end connected to the sprocket, it can be understood that by adopting the structure of the torsion spring fitted onto the first rivet, the spatial layout of the spring installation is simplified, and the rotational elasticity of the torsion spring acts directly between the swing block and the sprocket, providing a more stable restoring force, while reducing the number of parts and assembly complexity, and improving the reliability of the mechanism.

[0021] According to some embodiments of this utility model, the hinge center of the swing block and the sprocket is parallel to and not on the same axis as the rotation center of the sprocket.

[0022] The advantage is that by making the hinge center of the swing block and the sprocket parallel to and not on the same axis as the rotation center of the sprocket, this utility model optimizes the mechanical leverage ratio when the swing block swings, so that it can generate sufficient centrifugal force to trigger the action at low speed, thereby improving the action sensitivity and response speed.

[0023] According to some embodiments of the present invention, the exhaust cam is provided with a first sliding groove, one end of which extends outside the base circle surface of the exhaust cam, and the top pin slides on the first sliding groove to protrude from and recess into the base circle surface of the exhaust cam.

[0024] The advantage of this invention is that by providing a first groove on the exhaust cam, with one end of the first groove extending outside the base circle surface of the exhaust cam, and the top pin sliding on the first groove to protrude and retract into the base circle surface of the exhaust cam, it can be understood that the design of the first groove extending outside the base circle surface provides a clear sliding path guide for the top pin, avoiding the problem of uneven wear caused by lateral force on the top pin.

[0025] According to some embodiments of the present invention, the starting pressure reduction mechanism further includes a transmission shaft, which is coaxially and rotatably disposed within the camshaft. The transmission shaft is provided with a transmission part for abutting the top pin. The swing block swings to drive the transmission shaft to rotate relative to the camshaft, so that the transmission shaft drives the top pin to protrude from the base circle surface of the exhaust cam through the transmission part.

[0026] The advantages of this invention are that the starting pressure reduction mechanism also includes a transmission shaft, which is coaxially and rotatably mounted inside the camshaft. The transmission shaft is equipped with a transmission part for abutting the top pin. The swinging block drives the transmission shaft to rotate relative to the camshaft, so that the transmission shaft drives the top pin to protrude from the base circle surface of the exhaust cam through the transmission part. It can be understood that the coaxial design of the transmission shaft and the camshaft enables direct power transmission, while the top pin is indirectly driven through the transmission part, converting the swinging block's swing into the linear motion of the top pin. This not only isolates the impact of camshaft vibration on the swinging block, but also improves the synchronization of the action through mechanical linkage.

[0027] According to some embodiments of the present invention, the transmission part is configured as a cam, the convex surface of the cam abuts against the top pin to push the top pin out of the base circle surface of the exhaust cam, and the base circle surface of the cam cooperates with the top pin so that the top pin can be recessed into the exhaust cam.

[0028] The advantages are: by setting the transmission part as a cam, the convex surface of the cam abuts against the top pin to push the top pin out of the base circle surface of the exhaust cam, and the base circle surface of the cam cooperates with the top pin so that the top pin can be recessed into the exhaust cam. It can be understood that by using a cam as the transmission part, the lift curve of the top pin can be precisely controlled by utilizing its contour characteristics, which has both smooth operation and timely response.

[0029] According to some embodiments of the present invention, the top pin has a first groove that extends along the length of the top pin. The first groove accommodates the cam. When the cam pushes the top pin out of the base circle surface of the exhaust cam, the two ends of the first groove along the length of the top pin can respectively abut against the cam to define the position of the top pin.

[0030] The advantages of this invention are: by giving the top pin a first groove that extends along the length of the top pin and accommodates a cam, when the cam pushes the top pin out of the base circle surface of the exhaust cam, the two ends of the first groove along the length of the top pin can respectively abut against the cam to limit the position of the top pin. It can be understood that the bidirectional limiting structure of the first groove forms a hard stop point, which not only prevents the top pin from being pushed out excessively and causing valve interference, but also avoids disengagement when fully retracted. At the same time, the line contact between the groove wall and the cam can disperse stress and reduce the risk of local wear. In addition, when the cam pushes the top pin out of the base circle surface of the exhaust cam, the two ends of the first groove along the length of the top pin can respectively abut against the cam to limit the position of the top pin, ensuring that the protrusion height of the top pin outside the base circle surface is consistent and improving the pressure relief stability.

[0031] According to some embodiments of the present invention, the drive shaft is provided with a radially extending lever, and the swing block swings to drive the lever to swing so that the drive shaft rotates relative to the camshaft.

[0032] The advantages of this invention are: by setting a radially extending lever on the transmission shaft, the swinging block drives the lever to swing, so that the transmission shaft rotates relative to the camshaft. It can be understood that the lever extending radially along the transmission shaft converts the swinging block's swing into the rotational motion of the transmission shaft. By using the lever amplification principle, the driving force required for the swinging block is reduced. At the same time, the rigid transmission characteristics of the lever can eliminate the action delay caused by traditional flexible connections.

[0033] According to some embodiments of the present invention, one of the swing block and the lever is provided with a transmission pin, and the other of the swing block and the lever is provided with a transmission groove for accommodating the transmission pin, and the transmission pin and the transmission groove cooperate to transmit power.

[0034] The advantages of this invention are: One of the swing block and the lever is provided with a transmission pin, and the other is provided with a transmission groove to accommodate the transmission pin. The transmission pin and the transmission groove work together for transmission. It can be understood that the cooperation between the transmission pin and the transmission groove allows the transmission pin to abut against the two long side walls of the transmission groove, thus pushing the lever to swing. Simultaneously, the transmission groove allows the transmission pin to move along its length, allowing for changes in the contact position between the transmission pin and the transmission groove due to differences in their movement trajectories. This prevents the transmission pin and the lever from jamming together and improves the smoothness of the transmission between them.

[0035] An engine according to a second aspect of the present invention includes a starting decompression mechanism according to a first aspect of the present invention.

[0036] An engine according to an embodiment of the present invention has at least the following beneficial effects:

[0037] 1. This utility model movably sets a top pin on the exhaust cam. The top pin can protrude from and be recessed into the base circle surface of the exhaust cam. It can be understood that when the top pin protrudes from the base circle surface of the exhaust cam and the base circle surface of the exhaust cam abuts against the valve top sleeve, the internal combustion engine is in the compression process. At this time, the top pin can lift the valve top sleeve, realize the slight opening of the exhaust valve, release the gas pressure in the original sealed combustion chamber of the internal combustion engine, achieve the purpose of decompression, and effectively improve the problem of high engine starting resistance and difficulty in starting caused by excessive starting cylinder pressure.

[0038] 2. This utility model incorporates a swing block hinged to a sprocket. Under centrifugal force, the swing block oscillates along the hinge center between the swing block and the sprocket, causing the top pin to be recessed into the base circle surface of the exhaust cam. It can be understood that when the engine starts, the sprocket begins to rotate. Once the sprocket reaches a certain speed, i.e., when the engine is running normally after starting, the centrifugal force on the swing block can drive it to oscillate along the hinge center between the swing block and the sprocket. This allows the swing block to cause the top pin to be recessed into the base circle surface of the exhaust cam, thus rendering the pressure-reducing effect of the starting pressure-reducing mechanism ineffective during normal engine operation and preventing pressure leakage during normal engine operation.

[0039] 3. This utility model incorporates a spring that drives the sling block to reset, causing the sling block to cause the top pin to protrude from the base circle surface of the exhaust cam. It is understood that after the engine is turned off, the sprocket speed gradually decreases until it stops rotating, and the centrifugal force on the sling block also gradually decreases until it reaches zero. At this time, the spring can drive the sling block to reset, causing the sling block to cause the top pin to protrude from the base circle surface of the exhaust cam. Therefore, the starting decompression mechanism can restore its decompression function after the engine is turned off, and thus, when the engine is started again, the starting decompression mechanism can achieve its decompression function.

[0040] 4. This utility model features a first pin in one of the swing block and the sprocket, and an arc-shaped groove extending circumferentially along the hinge center between the swing block and the sprocket in the other. The first pin engages with the arc-shaped groove for guidance and limiting. This means that the swing stroke range of the swing block is precisely limited by the engagement of the first pin and the arc-shaped groove, preventing excessive displacement due to centrifugal force. This ensures stable and reliable protrusion / recession of the top pin. Simultaneously, the engagement of the arc-shaped groove with the first pin guides the swing path of the swing block and limits its maximum swing stroke, ensuring the stability of the top pin's position and guaranteeing the effectiveness of the pressure-reducing mechanism. This structure effectively solves the problem of top pin position fluctuation caused by unstable swing block stroke in traditional designs, significantly improving the consistency of the pressure-reducing mechanism's operation.

[0041] Additional aspects and advantages of this invention will be set forth in part in the description which follows, and in part will be obvious from the description, or may be learned by practice of the invention. Attached Figure Description

[0042] To more clearly illustrate the technical solutions of the embodiments of this utility model or the prior art, the drawings used in the description of the embodiments or the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of this utility model. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0043] Figure 1 This is a schematic diagram of the structure of a starting pressure reduction mechanism according to an embodiment of the present utility model;

[0044] Figure 2 for Figure 1 A cross-sectional view shown along the axis of the camshaft;

[0045] Figure 3 for Figure 2 The side view shown;

[0046] Figure 4 for Figure 2 The AA section view shown;

[0047] Figure 5 for Figure 2 A cross-sectional view showing the fit between the exhaust cam and the top pin;

[0048] Figure 6 for Figure 2 The diagram shows the structure of the sling block, drive shaft, and top pin assembly.

[0049] Reference numerals: 100-camshaft, 110-exhaust cam, 120-sprocket, 130-top pin, 140-swing block, 150-spring, 160-first pin, 170-arc groove, 180-first rivet, 190-first slide groove, 200-drive shaft, 210-drive unit, 220-first groove, 230-lever, 240-drive pin, 250-drive slide groove. Detailed Implementation

[0050] The embodiments of this utility model are described in detail below. Examples of these embodiments are shown in the accompanying drawings, wherein the same or similar reference numerals denote the same or similar elements or elements having the same or similar functions throughout. The embodiments described below with reference to the accompanying drawings are exemplary and are only used to explain this utility model, and should not be construed as limiting this utility model.

[0051] In the description of this utility model, it should be understood that the directional descriptions, such as up, down, front, back, left, right, etc., indicate the directional or positional relationship based on the directional or positional relationship shown in the accompanying drawings. They are only for the convenience of describing this utility model 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. Therefore, they should not be construed as limitations on this utility model.

[0052] In the description of this utility model, "several" means one or more, "multiple" means two or more, "greater than," "less than," and "exceeding" are understood to exclude the stated number, while "above," "below," and "within" are understood to include the stated number. If "first" and "second" are mentioned, it is only for the purpose of distinguishing technical features and should not be construed as indicating or implying relative importance or implicitly indicating the number of indicated technical features or the order of the indicated technical features.

[0053] In the description of this utility model, it should be noted that, unless otherwise explicitly specified and limited, the terms "installation, connection, and linkage" should be interpreted broadly. For example, they can refer to fixed connections, detachable connections, or integral connections; they can refer to mechanical connections or electrical connections; they can refer to direct connections or indirect connections through an intermediate medium; and they can refer to the internal communication between two components. Those skilled in the art can understand the specific meaning of the above terms in this utility model based on the specific circumstances.

[0054] The following is in conjunction with the appendix Figure 1 -Appendix Figure 6 This invention describes a starting decompression mechanism and an engine according to an embodiment of the present invention.

[0055] This utility model aims to provide an embodiment of a starting decompression mechanism and an engine.

[0056] In this embodiment, an engine mainly includes a starting decompression mechanism.

[0057] Reference Figure 1 and Figure 2 The decompression mechanism includes a camshaft 100, a sprocket 120, a top pin 130, a sling block 140, and a spring 150.

[0058] For camshaft 100, camshaft 100 has exhaust cam 110.

[0059] Specifically, when the base circular surface of the exhaust cam 110 supports the valve top sleeve, the exhaust valve is in a closed and sealed state; when the convex surface of the exhaust cam 110 supports the valve top sleeve, the exhaust valve is in an open and exhaust state.

[0060] For the structure and working principle of exhaust valves, existing technologies can be referenced.

[0061] For sprocket 120, sprocket 120 meshes with the timing chain of the engine and is used to drive camshaft 100 to rotate.

[0062] The top pin 130 is movably mounted on the exhaust cam 110, and the top pin 130 can protrude from and retract into the base circle surface of the exhaust cam 110.

[0063] It is understandable that when the top pin 130 protrudes from the base circle surface of the exhaust cam 110 and the base circle surface of the exhaust cam 110 abuts against the valve top sleeve, the internal combustion engine is in the compression process. At this time, the top pin 130 can lift the valve top sleeve to achieve a small opening of the exhaust valve, release the gas pressure in the original sealed combustion chamber of the internal combustion engine, achieve the purpose of decompression, and effectively improve the problem of high engine starting resistance and difficulty in starting caused by excessive starting cylinder pressure.

[0064] In some specific embodiments, the exhaust cam 110 is provided with a first groove 190, one end of which extends outside the base circle surface of the exhaust cam 110, and the top pin 130 slides on the first groove 190 to protrude from and recess into the base circle surface of the exhaust cam 110.

[0065] Understandably, the design of the first groove 190 extending beyond the base circle surface provides a clear sliding path guide for the top pin 130, avoiding the problem of uneven wear caused by lateral force on the top pin 130.

[0066] Reference Figure 3 For the swing block 140, the swing block 140 is hinged to the sprocket 120. Under the action of centrifugal force, the swing block 140 swings along the hinge center between the swing block 140 and the sprocket 120 to drive the top pin 130 to be recessed into the base circle surface of the exhaust cam 110.

[0067] Understandably, when the engine starts, the sprocket 120 begins to rotate. When the sprocket 120 reaches a certain speed, that is, when the engine is running normally after starting, the centrifugal force on the sprocket 140 can drive the sprocket 140 to swing around the hinge center between the sprocket 140 and the sprocket 120. This allows the sprocket 140 to drive the top pin 130 to be recessed into the base circle surface of the exhaust cam 110, so that the pressure reduction function of the starting pressure reduction mechanism fails when the engine is running normally, thus preventing the starting pressure reduction mechanism from releasing pressure when the engine is running normally.

[0068] Specifically, the sling block 140 and the sprocket 120 are hinged by the first rivet 180, the spring 150 is set as a torsion spring, the torsion spring is fitted on the first rivet 180, one end of the torsion spring is connected to the sling block 140, and the other end of the torsion spring is connected to the sprocket 120.

[0069] Understandably, the structure of using a torsion spring fitted onto the first rivet 180 simplifies the installation space layout of the spring 150. The rotational elasticity of the torsion spring acts directly between the swing block 140 and the sprocket 120, providing a more stable restoring force. At the same time, it reduces the number of parts and assembly complexity, and improves the reliability of the mechanism.

[0070] In some specific embodiments, the hinge center of the sprocket 140 and the sprocket 120 is parallel to and not on the same axis as the rotation center of the sprocket 120.

[0071] Understandably, by setting the hinge center to be parallel to and off-axis from the rotation center of the sprocket 120, the mechanical leverage ratio of the swing block 140 is optimized, so that it can generate sufficient centrifugal force to trigger the action at low speed, thereby improving the action sensitivity and response speed.

[0072] In some specific embodiments, one of the sling block 140 and the sprocket 120 is provided with a first pin 160, and the other of the sling block 140 and the sprocket 120 is provided with an arcuate groove 170 extending circumferentially along the hinge center of the sling block 140 and the sprocket 120. The first pin 160 cooperates with the arcuate groove 170 for guidance and limitation.

[0073] Understandably, by using the cooperation of the first pin 160 and the arc groove 170 to guide and limit the swing stroke range of the swing block 140, the swing block 140 can be precisely limited, avoiding excessive displacement of the swing block 140 due to centrifugal force. This ensures that the protrusion / recession of the top pin 130 is stable and reliable. At the same time, the cooperation between the arc groove 170 and the first pin 160 can guide the swing path of the swing block 140 and limit the maximum swing stroke of the swing block 140, ensuring the stability of the position of the top pin 130 and ensuring the effectiveness of starting the pressure relief mechanism. This structure can effectively solve the problem of position fluctuation of the top pin 130 caused by the unstable stroke of the traditional swing block 140, and significantly improve the consistency of the pressure relief mechanism's action.

[0074] Specifically, in order to make the fit between the first pin 160 and the arc groove 170 more stable, a pin cap can be set at the free end of the first pin 160. The pin cap is used to abut and limit the arc groove 170 in the sprocket 140 and prevent it from detaching.

[0075] Furthermore, the first pin 160 is disposed on the sprocket 120, and the arc groove 170 is disposed on the sling block 140.

[0076] Reference Figure 4 , Figure 5 and Figure 6In some specific embodiments, the decompression mechanism further includes a drive shaft 200, which is coaxially and rotatably disposed within the camshaft 100. The drive shaft 200 is provided with a transmission part 210 for abutting against the top pin 130. The swing block 140 swings to drive the drive shaft 200 to rotate relative to the camshaft 100, so that the drive shaft 200 drives the top pin 130 to protrude from the base circle surface of the exhaust cam 110 through the transmission part 210.

[0077] It is understandable that the coaxial design of the drive shaft 200 and the camshaft 100 enables direct power transmission. The top pin 130 is indirectly driven through the transmission unit 210, which converts the swing of the swing block 140 into the linear motion of the top pin 130. This not only isolates the impact of the vibration of the camshaft 100 on the swing block 140, but also improves the synchronization of the action through mechanical linkage.

[0078] Specifically, the transmission part 210 is configured as a cam, the convex surface of the cam abuts against the top pin 130 to push the top pin 130 out of the base circle surface of the exhaust cam 110, and the base circle surface of the cam cooperates with the top pin 130 so that the top pin 130 can be recessed into the exhaust cam 110.

[0079] It is understandable that by using a cam as the transmission unit 210, the lift curve of the top pin 130 can be precisely controlled by utilizing its contour characteristics, thus achieving both smooth operation and timely response.

[0080] Furthermore, the top pin 130 has a first groove 220 that extends along the length of the top pin 130. The first groove 220 accommodates a cam. When the cam pushes the top pin 130 out of the base circle surface of the exhaust cam 110, the two ends of the first groove 220 along the length of the top pin 130 can respectively abut against the cam to limit the position of the top pin 130.

[0081] Understandably, the bidirectional limiting structure of the first groove 220 forms a hard stop point, which not only prevents the top pin 130 from being excessively pushed out, causing valve interference, but also avoids disengagement when fully retracted. At the same time, the line contact between the groove wall and the cam can disperse stress and reduce the risk of local wear. In addition, when the cam pushes the top pin 130 out of the base circle surface of the exhaust cam 110, the two ends of the first groove 220 along the length direction of the top pin 130 can respectively abut against the cam to limit the position of the top pin 130, ensuring that the protrusion height of the top pin 130 outside the base circle surface is consistent and improving the pressure relief stability.

[0082] Furthermore, the profile of the cam can be made waist-shaped, meaning that the two ends of the cam are symmetrical and the middle is concave.

[0083] In some specific embodiments, the drive shaft 200 is provided with a radially extending lever 230, and the swing block 140 swings to drive the lever 230 to swing so that the drive shaft 200 rotates relative to the camshaft 100.

[0084] It is understandable that the lever 230, which extends radially along the drive shaft 200, converts the swing of the swing block 140 into the rotational motion of the drive shaft 200. By lever amplification principle, the driving force required for the swing block 140 is reduced. At the same time, the rigid transmission characteristics of the lever 230 can eliminate the motion lag caused by traditional flexible connection.

[0085] Furthermore, one of the swing block 140 and the lever 230 is provided with a transmission pin 240, and the other of the swing block 140 and the lever 230 is provided with a transmission groove 250 for accommodating the transmission pin 240. The transmission pin 240 and the transmission groove 250 cooperate to transmit power.

[0086] Understandably, the cooperation between the transmission pin 240 and the transmission groove 250 allows the transmission pin 240 to abut against the two long side walls of the transmission groove 250, which in turn pushes the lever 230 to swing. At the same time, the transmission groove 250 allows the transmission pin 240 to move along its length, allowing for changes in the contact position between the transmission pin 240 and the transmission groove 250 caused by the difference in the movement trajectories of the transmission pin 240 and the lever 230. This prevents the transmission pin 240 and the lever 230 from jamming together and improves the smoothness of transmission between the transmission pin 240 and the lever 230.

[0087] Specifically, the transmission pin 240 is mounted on the swing block 140, and the transmission groove 250 is mounted on the lever 230.

[0088] Spring 150 is used to drive the sling block 140 to reset so that the sling block 140 drives the top pin 130 to protrude from the base circle surface of the exhaust cam 110.

[0089] Understandably, after the engine is turned off, the speed of the sprocket 120 gradually decreases until it stops rotating, and the centrifugal force on the sling block 140 also gradually decreases until it becomes zero. At this time, the spring 150 can drive the sling block 140 to reset, so that the sling block 140 drives the top pin 130 to protrude from the base circle surface of the exhaust cam 110. Thus, the starting decompression mechanism can restore its decompression function after the engine is turned off, and when the engine is started again, the starting decompression mechanism can achieve the decompression function.

[0090] In the description of this specification, references to terms such as "an embodiment," "some embodiments," "illustrative embodiments," "example," "specific example," or "some examples," etc., indicate that a specific feature, structure, material, or characteristic described in connection with that embodiment or example is included in at least one embodiment or example of the present invention. In this specification, illustrative expressions of the above terms do not necessarily refer to the same embodiment or example. Furthermore, the specific features, structures, materials, or characteristics described may be combined in any suitable manner in one or more embodiments or examples.

[0091] The terms "first," "second," "third," "fourth," etc. (if applicable) in the specification, claims, and accompanying drawings of this application are used to distinguish similar objects and are not necessarily used to describe a specific order or sequence. It should be understood that such data can be interchanged where appropriate so that the embodiments described herein can be implemented in a sequence other than that illustrated or described herein.

[0092] It should also be noted that, in the description of this specification, relational terms such as first and second are used only to distinguish one entity or operation from another entity or operation, and do not necessarily require or imply any such actual relationship or order between these entities or operations.

[0093] Furthermore, the terms “comprising” and “having”, and any variations thereof, are intended to cover non-exclusive inclusion, such that a process, method, system, product, or apparatus that includes a series of steps or units is not necessarily limited to those steps or units that are explicitly listed, but may also include other steps or units that are not explicitly listed or that are inherent to such processes, methods, products, or apparatus.

[0094] Furthermore, the terms "comprising," "including," or any other variations thereof are intended to cover non-exclusive inclusion, such that a process, method, article, or apparatus that comprises a list of elements includes not only those elements but also other elements not expressly listed, or elements inherent to such a process, method, article, or apparatus. Without further limitation, an element defined by the phrase "comprising one..." does not exclude the presence of other identical elements in the process, method, article, or apparatus that includes said element.

[0095] The embodiments of the present utility model have been described in detail above with reference to the accompanying drawings. However, the present utility model is not limited to the above embodiments. Within the scope of knowledge possessed by those skilled in the art, various changes can be made without departing from the spirit of the present utility model.

Claims

1. A start-up pressure reduction mechanism characterized by comprising: include: Camshaft (100) with exhaust cam (110); The sprocket (120) meshes with the timing chain of the engine and is used to drive the camshaft (100) to rotate; A top pin (130) is movably disposed on the exhaust cam (110) and can protrude from and recess into the base circle surface of the exhaust cam (110); A swing block (140) is hinged to the sprocket (120). Under the action of centrifugal force, the swing block (140) swings along the hinge center between the swing block (140) and the sprocket (120) to drive the top pin (130) to be recessed into the base circle surface of the exhaust cam (110). A spring (150) is used to drive the sling block (140) to reset so that the sling block (140) drives the top pin (130) to protrude from the base circle surface of the exhaust cam (110); One of the sling block (140) and the sprocket (120) is provided with a first pin (160), and the other of the sling block (140) and the sprocket (120) is provided with an arc-shaped groove (170) extending circumferentially along the hinge center of the sling block (140) and the sprocket (120). The first pin (160) cooperates with the arc-shaped groove (170) for guidance and limitation.

2. A start pressure reducing mechanism according to claim 1, wherein The sling block (140) and the sprocket (120) are hinged by a first rivet (180). The spring (150) is a torsion spring, which is fitted on the first rivet (180). One end of the torsion spring is connected to the sling block (140), and the other end of the torsion spring is connected to the sprocket (120).

3. The starting pressure reduction mechanism according to claim 1, characterized in that, The hinge center of the sprocket (140) and the sprocket (120) is parallel to and off-axis from the rotation center of the sprocket (120).

4. A priming pressure relief mechanism according to claim 1, wherein The exhaust cam (110) is provided with a first groove (190), one end of which extends to the outside of the base circle surface of the exhaust cam (110), and the top pin (130) slides on the first groove (190) to protrude from and recess into the base circle surface of the exhaust cam (110).

5. A priming pressure relief mechanism according to claim 1, wherein It also includes a drive shaft (200), which is coaxially rotatably disposed within the camshaft (100) and the drive shaft (200). The drive shaft (200) is provided with a transmission part (210) for abutting the top pin (130). The swing block (140) swings to drive the drive shaft (200) to rotate relative to the camshaft (100), so that the drive shaft (200) drives the top pin (130) to protrude from the base circle surface of the exhaust cam (110) through the transmission part (210).

6. The starting pressure reduction mechanism according to claim 5, characterized in that, The transmission part (210) is configured as a cam, the convex surface of the cam abuts against the top pin (130) to push the top pin (130) out of the base circle surface of the exhaust cam (110), and the base circle surface of the cam cooperates with the top pin (130) so that the top pin (130) can be recessed into the exhaust cam (110).

7. The starting pressure reduction mechanism according to claim 6, characterized in that, The top pin (130) has a first groove (220) extending along the length of the top pin (130). The first groove (220) accommodates the cam. When the cam pushes the top pin (130) out of the base circle surface of the exhaust cam (110), the two ends of the first groove (220) along the length of the top pin (130) can respectively abut against the cam to define the position of the top pin (130).

8. A priming pressure relief mechanism according to claim 5, wherein The drive shaft (200) is provided with a radially extending lever (230), and the swing block (140) swings to drive the lever (230) to swing so that the drive shaft (200) rotates relative to the camshaft (100).

9. A priming pressure relief mechanism according to claim 8, wherein One of the swing block (140) and the lever (230) is provided with a transmission pin (240), and the other of the swing block (140) and the lever (230) is provided with a transmission groove (250) for accommodating the transmission pin (240). The transmission pin (240) and the transmission groove (250) cooperate to transmit power.

10. An engine characterized by, Includes a pressure-reducing mechanism as described in any one of claims 1 to 9.

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