阅读说明：本技术 一种发动机启动减压结构 (Engine starting pressure reducing structure ) 是由 郑林 蔡良正 张立成 潘江伟 金潮 于 2020-12-02 设计创作，主要内容包括：本发明提供了一种发动机启动减压结构,属于摩托车技术领域。它解决现有发动机启动减压结构易导致发动机工作稳定性降低的问题。本发动机启动减压结构包括具有润滑通道和排气凸轮的凸轮轴,排气凸轮上沿径向开设有与润滑通道连通且具有孔底的销孔,所述销孔内滑动设置有减压销,减压销能够在销孔内进行伸缩使得减压销的外端高于或低于排气凸轮的基圆表面,排气凸轮上还开设有通孔,所述通孔位于销孔的中心线的一侧且通孔的入口端位于销孔的孔底上,所述通孔的出口端位于排气凸轮的侧壁上,在排气凸轮的径向上所述通孔的出口端位于入口端的外侧。本发明使得气门摇臂工作稳定,进而有利于发动机的稳定工作。(The invention provides an engine starting pressure reducing structure, and belongs to the technical field of motorcycles. The problem that the working stability of an engine is easily reduced due to the fact that an existing engine starting pressure reducing structure is used is solved. This engine starts decompression structure is including the camshaft that has lubricated passageway and exhaust cam, radially offers on the exhaust cam with lubricated passageway intercommunication and have the pinhole of hole bottom, it is provided with the decompression round pin to slide in the pinhole, and the decompression round pin can stretch out and draw back in the pinhole and make the outer end of decompression round pin be higher than or be less than the base circle surface of exhaust cam, has still seted up the through-hole on the exhaust cam, the through-hole is located one side of the central line of pinhole and the entry end of through-hole is located the hole bottom of pinhole, the exit end of through-hole is located the lateral wall of exhaust cam, radially at the exhaust cam the exit end of through-hole is located the outside of entry end. The invention ensures that the valve rocker works stably, thereby being beneficial to the stable work of the engine.)

1. The utility model provides an engine starts decompression structure, includes camshaft (1) that has lubricated passageway (1a) and exhaust cam (1b), radially offer on exhaust cam (1b) with lubricated passageway (1a) intercommunication and have pinhole (2) of hole bottom (21), it has decompression round pin (3) to slide in pinhole (2), decompression round pin (3) can stretch out and draw back in pinhole (2) and make the outer end of decompression round pin (3) be higher than or be less than exhaust cam (1b) base circle surface, characterized in that, still offer through-hole (4) on exhaust cam (1b), through-hole (4) are located one side of the central line of pinhole (2) and the entry end of through-hole (4) is located pinhole bottom (21) of pinhole (2), the exit end of through-hole (4) is located the lateral wall of exhaust cam (1b), radially of exhaust cam (1b) the exit end of through-hole (4) is located the outside of entry end.

2. The engine starting decompression structure according to claim 1, wherein a length direction of the through hole (4) coincides with a radial direction of the camshaft (1).

3. The engine starting decompression structure according to claim 1 or 2, wherein a drainage groove (5) is further formed in a side wall of the exhaust cam (1b), and a groove wall of the drainage groove (5) is coplanar with a hole wall of the through hole (4).

4. The engine starting decompression structure according to claim 3, wherein the outer peripheral surface of the exhaust cam (1b) has a valve opening section (1b1), the drainage groove (5) is a straight groove, the length direction of the drainage groove (5) coincides with the radial direction of the camshaft (1), and one end of the drainage groove (5) away from the through hole (4) has a port (51) located at the edge of the surface of the valve opening section (1b1) of the exhaust cam (1 b).

5. The engine start decompression structure according to claim 1 or 2, characterized in that the exhaust cam (1b) further has a thickened portion (1c) on a side wall thereof, and the through hole (4) is partially provided on the thickened portion (1 c).

6. The engine starting decompression structure according to claim 1 or 2, wherein the decompression pin (3) is a cylindrical pin, and an inner end surface of the decompression pin (3) is a conical surface or a circular table surface.

7. The engine start decompression structure according to claim 5, wherein the camshaft (1) includes a shaft body (1d), and the thickened portion (1c) is of an integral structure with the shaft body (1d) of the camshaft (1).

8. The engine starting pressure reducing structure according to claim 7, wherein the lubricating channel (1a) is a central hole formed in the shaft body (1d), a pivot (6) penetrates through the central hole, one end of the pivot (6) is provided with an eccentrically arranged shifting pin (61), and a lateral mounting groove (31) for the shifting pin (61) to extend into is formed in a side wall of the pressure reducing pin (3).

9. The engine starting decompression structure according to claim 8, wherein the bottom (21) of the pin hole (2) is concave, and when the pivot (6) drives the decompression pin (3) to retract to the innermost position, a gap is formed between the inlet end of the through hole (4) and the inner end surface of the decompression pin (3).

Technical Field

The invention belongs to the technical field of motorcycles, and relates to an engine starting pressure reducing structure.

Background

When the motorcycle engine is started, new gas needs to be sucked for compression, great compression resistance is generated near the compression end point, and at the moment, if decompression is not performed, the starting force is increased, and starting is very difficult, so that decompression needs to be performed by adopting a decompression structure to ensure that the engine is started smoothly.

The decompression structure is usually arranged on a camshaft, and for example, a two-cylinder engine starting decompression valve structure (application number: CN 201920924386.3; publication number: CN210068259U) disclosed in chinese patent document includes a hollow camshaft, two exhaust cams corresponding to two cylinders of the engine are arranged on the camshaft, a rotatable decompression center shaft is arranged in the camshaft, two decompression tappets corresponding to the exhaust cams are arranged on the decompression center shaft, a longitudinal limit groove is arranged on the decompression tappets, and mounting holes for mounting the decompression tappets are arranged on the camshaft. In order to meet the lubricating requirements of the surface of the camshaft and the rocker roller, a central hole is also formed in the camshaft for lubricating oil to pass through. The bottom of mounting hole and the centre bore of camshaft are the intercommunication all the time for the vertical spacing groove on the decompression tappet, and at the in-process of decompression tappet retraction mounting hole, in the hole bottom of mounting hole department oil, the gas medium can be arranged to the centre bore of camshaft from the hole bottom of mounting hole in to make in the decompression round pin can the retraction mounting hole. In the actual working process, the pressure reducing structure has the following defects:

firstly, the oil and gas media at the bottom of the mounting hole can be discharged to the central hole of the camshaft from the bottom of the mounting hole, and the thrust generated in the retraction process of the pressure reducing tappet is realized, so that the larger damping can exist in the process of retracting the pressure reducing tappet into the mounting hole, the smooth retraction of the pressure reducing tappet is not facilitated, the condition that the valve is not tightly closed due to untimely retraction of the pressure reducing tappet is easy to occur, the combustion of an engine is insufficient, the power reduction and the fuel consumption of the engine are obviously increased, and the working stability of the engine is influenced.

In addition, under the condition that the longitudinal limiting groove is formed in the decompression tappet, in order to enable oil and gas media at the bottom of the mounting hole to be quickly discharged into the central hole of the camshaft, the longitudinal limiting groove needs to have a certain depth so as to ensure that the bottom of the mounting hole is communicated with the central hole of the camshaft to form a large opening. However, the deeper the longitudinal limiting groove is dug, the smaller the fitting area between the pressure reduction tappet and the mounting hole is, so that the mounting hole is difficult to stably guide the telescopic movement of the pressure reduction tappet, the stability and the precision of the movement of the pressure reduction tappet are reduced, and the engine is difficult to normally start due to the fact that the pressure reduction failure easily occurs.

Disclosure of Invention

The invention aims to solve the problems in the prior art, provides an engine starting pressure reducing structure, and solves the problem that the working stability of an engine is easily reduced due to the existing engine starting pressure reducing structure.

The purpose of the invention can be realized by the following technical scheme: the utility model provides an engine starts decompression structure, includes the camshaft that has lubricated passageway and exhaust cam, radially set up on the exhaust cam with lubricated passageway intercommunication and have the pinhole of hole bottom, it is provided with the decompression round pin to slide in the pinhole, the decompression round pin can stretch out and draw back in the pinhole and make the outer end of decompression round pin be higher than or be less than the base circle surface of exhaust cam, its characterized in that, still seted up the through-hole on the exhaust cam, the through-hole is located one side of the central line of pinhole and the entry end of through-hole is located the hole bottom of pinhole, the exit end of through-hole is located the lateral wall of exhaust cam, radially of exhaust cam the exit end of through-hole is located the outside of entry end.

The opening of one end of the pin hole is positioned on the base circle surface of the exhaust cam, and the other end of the pin hole is closed to form a hole bottom. When the engine is flamed out, the outer end of the decompression pin is higher than the base circle surface of the exhaust cam, so that the decompression effect is achieved, and the decompression effectiveness is ensured when the engine is started next time. When the engine is started, the camshaft starts to rotate, when the camshaft reaches a certain rotating speed, the decompression pin can be retracted into the pin hole, the outer end of the decompression pin is lower than the base circle surface of the exhaust cam, and the decompression structure does not play a role in decompression. The lubricating channel of the exhaust cam is used for introducing lubricating oil, so that the contact part of the rocker roller and the camshaft is lubricated, overheating and abrasion caused by friction are avoided, and the pin hole is communicated with the lubricating channel, so that the pressure reducing pin is lubricated.

The exhaust cam rotates the in-process, can produce centrifugal force and make the interior fluid of pinhole also have the trend of being thrown away, and through seting up the through-hole on the exhaust cam in this decompression structure, make the entry end of through-hole be located the hole bottom of pinhole, and the exit end is located the lateral wall of exhaust cam, and, the radial exit end of through-hole is located the outside of entry end at the exhaust cam, just so can utilize the effect of centrifugal force to get rid of the oil between the inner of decompression round pin and the pinhole hole bottom of pinhole, the gaseous medium is got rid of the hole bottom department to the pinhole fast, discharge smoothly from the through-hole of hole bottom department again, thereby effectively reduced the resistance of decompression round pin retraction process, guarantee that the decompression round pin can smoothly retract into the pinhole. This design makes this exhaust structure effectively avoid the outer end of decompression round pin to be higher than the base circle surface of exhaust cam unusually and lead to the condition that the valve closed not tight, guarantees the stability of engine work.

Meanwhile, the through hole is arranged on one side of the central line of the pin hole, so that the outlet end of the through hole is positioned on the side wall of the exhaust cam, the structure avoids the condition that the surface of the exhaust cam forms a fall due to the fact that an orifice is formed on the surface of the valve opening section, the smoothness is good and the shaking cannot occur when the roller of the valve rocker is in contact with the surface of the exhaust cam, the valve rocker works stably, and the stable work of an engine is facilitated.

In addition, this decompression structure passes through the through-hole and realizes the discharge of oil, gaseous medium, consequently need not to set up the breach of fuel feeding, the passing through of gaseous medium on the lateral wall of decompression round pin for have great cooperation area between decompression round pin and the pinhole, the pinhole can better lead the flexible of decompression round pin, has guaranteed the flexible stability and the precision of decompression round pin, thereby can avoid appearing the condition that the decompression became invalid, ensures that the engine can normally start all the time.

In the above-described engine starting decompression structure, a longitudinal direction of the through hole coincides with a radial direction of the camshaft. In the rotating process of the camshaft, radial centrifugal force is generated, the length direction of the through hole is consistent with the radial direction of the camshaft, so that oil and gas media between the inner end of the decompression pin and the bottom of the pin hole can be discharged most smoothly and quickly under the action of the centrifugal force, and the decompression pin can be guaranteed to be smoothly retracted into the pin hole.

In the engine starting pressure reducing structure, the side wall of the exhaust cam is further provided with a drainage groove, and the groove wall of the drainage groove is coplanar with the hole wall of the through hole. When the exhaust cam is provided with the through hole, the through hole needs to be ensured to have a larger aperture in order to quickly discharge oil and gas media. However, since the size of the exhaust cam of the motorcycle is generally small and the through hole needs to be arranged to avoid the contact surface between the exhaust cam and the rocker roller, it is very difficult to make the aperture of the through hole as large as possible in a limited space. Therefore, the pressure reducing structure is provided with the drainage groove on the side wall of the exhaust cam, the groove wall of the drainage groove is coplanar with the hole wall of the through hole, the through hole is ensured to have a larger aperture, and meanwhile, the working stability of the valve rocker is not influenced by the fall formed on the contact surface of the exhaust cam and the rocker roller.

In the engine starting pressure reducing structure, the outer peripheral surface of the exhaust cam is provided with the valve opening section, the drainage groove is a straight groove, the length direction of the drainage groove is consistent with the radial direction of the camshaft, and one end, far away from the through hole, of the drainage groove is provided with a port located on the edge of the surface of the valve opening section of the exhaust cam. The drainage groove has the port for straight flute and one end, and the length direction of drainage groove is unanimous with the radial direction of camshaft simultaneously for under the effect of centrifugal force, the fluid of arranging in the drainage groove can be thrown away from the port fast, thereby is favorable to oil, the gaseous medium of pinhole hole bottom department to discharge fast. And the port of the drainage groove is arranged at the edge of the surface of the opening section of the exhaust cam valve, so that the contact with a roller of the valve rocker is avoided, the valve rocker works stably, and the stable work of the engine is facilitated.

In the engine starting decompression structure described above, the exhaust cam further has a thickened portion on a side wall thereof, and the through hole portion is provided on the thickened portion. Due to the design, the through hole has a larger aperture, and oil and gas media at the bottom of the pin hole can be rapidly discharged.

In the engine starting pressure reducing structure, the pressure reducing pin is a cylindrical pin, and the end surface of the inner end of the pressure reducing pin is a conical surface or a circular table surface. The through hole is eccentrically arranged relative to the pin hole, and the end surface of the inner end of the pressure reducing pin is a conical surface or a circular table surface, so that the pressure reducing pin has the function of radially pushing oil and gas media in the pin hole in the process of retracting into the pin hole, and the oil and gas media in the pin hole can be more smoothly discharged from the eccentric through hole.

In the above-mentioned engine starting decompression structure, the camshaft includes a shaft body, and the thickened portion is of an integral structure with the shaft body of the camshaft. Such a structure is not only easy to manufacture, but also has a high strength of the thickened portion.

In the engine starting pressure reducing structure, the lubricating channel is a central hole formed in the shaft body, a pivot shaft penetrates through the central hole, one end of the pivot shaft is provided with an eccentrically arranged shifting pin, and the side wall of the pressure reducing pin is provided with a transverse mounting groove for the shifting pin to extend into. Because the shifting pin is eccentrically arranged, the pressure reducing pin can be driven to stretch in the pin hole when the pivot rotates, and the pressure reducing function is opened and closed.

In the engine starting pressure reducing structure, the bottom of the pin hole is a concave structure, and when the pivot drives the pressure reducing pin to retract to the innermost position, a gap is formed between the inlet end of the through hole and the inner end face of the pressure reducing pin. When such design makes decompression round pin retraction to the innermost position, the entry end of through-hole also can not be sheltered from to the decompression round pin for when the decompression round pin retracts to arbitrary position in to the pinhole, the homoenergetic guarantees that the through-hole smoothly discharges oil, gas medium. The bottom of the pin hole is of a concave structure, so that the through hole forms a large opening on the bottom of the pin hole, and oil and gas media can be discharged quickly.

Compared with the prior art, the engine starting pressure reducing structure has the following advantages:

1. in this engine start decompression structure, the resistance of decompression round pin retraction process has effectively been reduced in setting up of through-hole, guarantees that the decompression round pin can retract the round pin downthehole smoothly, has effectively avoided the outer end of decompression round pin to be higher than the base circle surface of exhaust cam unusually and leads to the condition that the valve closed not tight, guarantees the stability of engine work.

2. In the starting pressure reducing structure of the engine, the through hole is arranged on one side of the central line of the pin hole, so that the outlet end of the through hole is positioned on the side wall of the exhaust cam, the structure avoids the condition that the surface of the valve opening section forms an orifice to cause the surface of the exhaust cam to form a fall, the smoothness is good and the shake cannot occur when the roller of the valve rocker contacts with the surface of the exhaust cam, the valve rocker works stably, and the stable work of the engine is facilitated.

Drawings

Fig. 1 is a schematic perspective view of the present invention in a depressurized state.

Fig. 2 is a sectional view of the present invention in a reduced pressure state.

Fig. 3 is an enlarged view at a in fig. 2.

Fig. 4 is a schematic view of the camshaft in elevation with its base circular surface.

Fig. 5 is a perspective view of the camshaft.

Fig. 6 is a perspective view of the pressure relief pin.

Fig. 7 is a perspective view of the pivot.

Fig. 8 is a schematic perspective view of the pressure reducing function of the present invention when it is off.

Fig. 9 is a schematic perspective view of the pressure reducing function of the present invention when it is off.

In the figure, 1, a camshaft; 1a, a lubricating channel; 1b, an exhaust cam; 1b1, valve opening segment; 1c, a thickened portion; 1d, a shaft body; 2. a pin hole; 21. bottom of the hole; 3. a decompression pin; 31. a transverse mounting groove; 4. a through hole; 5. a drainage groove; 51. a port; 6. a pivot; 61. pulling a pin; 7. throwing blocks; 8. a torsion spring; 9. and a sprocket.

Detailed Description

The following are specific embodiments of the present invention and are further described with reference to the drawings, but the present invention is not limited to these embodiments.

Example one

As shown in fig. 1 and 2, the engine starting pressure reducing structure includes a camshaft 1, a pivot shaft 6, a thrower 7, and the like, wherein the camshaft 1 includes a shaft body 1d and an exhaust cam 1b integrally formed with the shaft body 1d, a lubricating passage 1a is provided in the shaft body 1d of the camshaft 1, in an embodiment, the lubricating passage 1a is a central hole opened in the shaft body 1d, and the pivot shaft 6 is inserted into the central hole. One end of the camshaft 1 is fixedly connected with a chain wheel 9, the side wall of the chain wheel 9 is provided with a throwing block 7 which is hinged to the side wall of the chain wheel 9, the throwing block 7 can be thrown out along the radial direction of the chain wheel 9 under the action of centrifugal force, and the throwing block 7 is further connected with a torsion spring 8 which is used for enabling the throwing block 7 to reset. The throw 7 is connected to one end of the pivot 6 so that the throw 7 can rotate the pivot 6 when swinging. The exhaust cam 1b is provided with a pin hole 2 communicated with the lubricating channel 1a along the radial direction, an opening at one end of the pin hole 2 is positioned on the base circle surface of the exhaust cam 1b, and the other end of the pin hole 2 is closed to form a hole bottom 21. The pressure reducing pin 3 is arranged in the pin hole 2 in a sliding mode, the pressure reducing pin 3 is a cylindrical pin, and the end face of the inner end of the pressure reducing pin 3 is a circular table face. The decompression pin 3 can be extended and retracted within the pin hole 2 such that the outer end of the decompression pin 3 is higher or lower than the base circular surface of the exhaust cam 1 b.

As shown in fig. 2 to 5, the exhaust cam 1b is further provided with a through hole 4, the length direction of the through hole 4 is consistent with the radial direction of the camshaft 1, the through hole 4 is located on one side of the center line of the pin hole 2, the inlet end of the through hole 4 is located on the bottom 21 of the pin hole 2, the outlet end of the through hole 4 is located on the side wall of the exhaust cam 1b, and the outlet end of the through hole 4 is located on the outer side of the inlet end in the radial direction of the exhaust cam 1 b. The side wall of the exhaust cam 1b is also provided with a drainage groove 5, and the groove wall of the drainage groove 5 is coplanar with the hole wall of the through hole 4. The outer peripheral surface of the exhaust cam 1b is provided with a valve opening section 1b1, the drainage groove 5 is a straight groove, the length direction of the drainage groove 5 is consistent with the radial direction of the camshaft 1, and one end, far away from the through hole 4, of the drainage groove 5 is provided with a port 51 positioned on the surface edge of the valve opening section 1b1 of the exhaust cam 1 b. The exhaust cam 1b further has a thickened portion 1c on the side wall thereof, and the through hole 4 is partially provided in the thickened portion 1c, and the thickened portion 1c is formed integrally with the shaft body 1d of the camshaft 1. The arrangement of the thickened portion 1c and the drainage groove 5 enables the through hole 4 to have a larger aperture, and meanwhile, the working stability of the valve rocker is not affected due to the fact that the difference is formed between the contact surface of the exhaust cam 1b and the rocker roller. Moreover, the port 51 of the drainage groove 5 is arranged at the edge of the surface of the valve opening section 1b1 of the exhaust cam 1b to avoid the contact with a valve rocker roller, so that the valve rocker works stably, and the stable work of the engine is further facilitated.

As shown in fig. 6 and 7, one end of the pivot shaft 6 has an eccentrically disposed pin 61, and the side wall of the pressure-reducing pin 3 is provided with a lateral mounting groove 31 into which the pin 61 is inserted. Because the shifting pin 61 is eccentrically arranged, when the pivot 6 rotates, the pressure reducing pin 3 can be driven to extend and contract in the pin hole 2, and the opening and closing of the pressure reducing function are realized.

As shown in fig. 9, the bottom 21 of the pin hole 2 has a concave structure, which may be a conical surface or a concave spherical surface. When the pivot 6 drives the decompression pin 3 to retract to the innermost position, a gap is formed between the inlet end of the through hole 4 and the inner end surface of the decompression pin 3. When the decompression pin 3 retracts to the innermost position due to the design, the inlet end of the through hole 4 cannot be shielded by the decompression pin 3, and the through hole 4 can be ensured to smoothly discharge oil and gas media when the decompression pin 3 retracts to any position in the pin hole 2. The bottom 21 of the pin hole 2 is a conical surface, so that the through hole 4 forms a larger opening on the bottom 21 of the pin hole 2, and oil and gas media can be discharged quickly.

The working principle of the engine starting pressure reducing structure is as follows:

as shown in fig. 1 and 2, when the engine is shut down, the swinging block 7 is always in the return loading state due to the action of the torsion spring 8, and the outer end of the decompression pin 3 is higher than the base circle surface of the exhaust cam 1b at the moment, so that the decompression effect is achieved, and the decompression effectiveness is ensured when the engine is started next time.

As shown in fig. 8 and 9, when the engine is started, the camshaft 1 starts to rotate, and when the camshaft 1 reaches a certain rotation speed, the throwing block 7 is thrown out under the action of centrifugal force and drives the pivot 6 to rotate, the pivot 6 rotates to drive the decompression pin 3 to retract into the pin hole 2, so that the outer end of the decompression pin 3 is lower than the base circle surface of the exhaust cam 1b, and the decompression structure does not play a decompression role at this time. In the process that the pressure reducing pin 3 retracts into the pin hole 2, under the action of centrifugal force, oil and gas media between the inner end of the pressure reducing pin 3 and the bottom 21 of the pin hole 2 are quickly thrown to the bottom 21 of the pin hole 2 and then smoothly discharged from the through hole 4 at the bottom 21, so that the resistance of the pressure reducing pin 3 in the retracting process is effectively reduced, and the pressure reducing pin 3 can be guaranteed to retract into the pin hole 2 smoothly. This design makes this exhaust structure effectively avoid the outer end of decompression round pin 3 to be higher than the base circle surface of exhaust cam 1b unusually and lead to the condition that the valve closed not tight, guarantees the stability of engine work.

Example two

The structure and principle of this embodiment are basically the same as those of the first embodiment, and different points are as follows: the end surface of the inner end of the decompression pin 3 is a conical surface.

The specific embodiments described herein are merely illustrative of the spirit of the invention. Various modifications or additions may be made to the described embodiments or alternatives may be employed by those skilled in the art without departing from the spirit or ambit of the invention as defined in the appended claims.

Although 1, camshaft is used more herein; 1a, a lubricating channel; 1b, an exhaust cam; 1b1, valve opening segment; 1c, a thickened portion; 1d, a shaft body; 2. a pin hole; 21. bottom of the hole; 3. a decompression pin; 31. a transverse mounting groove; 4. a through hole; 5. a drainage groove; 51. a port; 6. a pivot; 61. pulling a pin; 7. throwing blocks; 8. a torsion spring; 9. sprocket, etc., but does not exclude the possibility of using other terms. These terms are used merely to more conveniently describe and explain the nature of the present invention; they are to be construed as being without limitation to any additional limitations that may be imposed by the spirit of the present invention.