A small engine for agricultural and forestry machinery

Abstract

In order to solve the problem that the existing engines are large in size, resulting in poor portability and being unsuitable for use in agricultural and forestry machinery, the present invention provides a small engine for agricultural and forestry machinery, comprising a piston cylinder body, an air intake seat, a carburetor and a starter; wherein the starter is drivingly connected to the piston cylinder body, the air intake seat is connected to the carburetor, and the carburetor is connected to the air inlet on the piston cylinder body; the piston cylinder body comprises a crankshaft transmission structure, a left cylinder body, a right cylinder body, a sealing gasket, a combustion chamber and an ignition structure; wherein the left cylinder body and the right cylinder body are fixedly connected; a crankshaft transmission structure is arranged between the left cylinder body and the right cylinder body; a transmission rod in the crankshaft transmission structure extends into the combustion chamber and is connected to a piston arranged in the combustion chamber; an ignition structure and a through hole connected to the carburetor are arranged above the combustion chamber; the small engine also comprises a centrifugal intake structure; the overall structure of the engine is compact and the volume is small.

Description

Technical Field

[0001] The present invention relates to the technical field of engines, and in particular to a small engine for agricultural and forestry machinery. Background Art

[0002] As one of the major categories of engines, internal combustion engines have been widely used in various mechanical equipment. The internal combustion engine includes spark plugs, carburetors, cylinders, crankshafts, etc. After the fuel and air are evenly mixed by the carburetors, they are sprayed into the active cavity of the piston cylinder in the form of droplets. Then, the fuel and air mixture is ignited by the spark plugs, resulting in explosions that push the piston cylinder, thereby realizing the rotation of the crankshaft connected to the piston cylinder, such as the content shown in the patent application publication number CN113606036A.

[0003] For engines used in agricultural and forestry machinery, such as engines on lawn mowers or other field tools, portability is the top priority; however, existing engines are usually large in size, with supercharged intake, water cooling, multi-cylinder and other structures, making the overall structure bulky. Although the power is stronger, it sacrifices portability. Engines used in agricultural and forestry machinery usually need to operate in multiple areas when in use, so it is very important to design compact agricultural and forestry machinery engines that are small in size and light in weight.

[0004] On the other hand, due to the influence of the use environment, as the blades inhale the airflow, a large amount of dust, wood chips, etc. will also be inhaled into the engine casing. Although it will not directly affect the interior of the engine, it will also adhere to the shaft, blades and other moving parts, affecting its performance. In particular, some moving parts of the engine are also coated with a large amount of lubricating oil, which is more likely to absorb impurities. On the one hand, it is difficult to clean, and on the other hand, it is easy to cause hidden dangers, affecting the service life and performance. In some other existing engine structures, a filter is also set to filter the inhaled cooling airflow, but the filter needs to be replaced regularly, which is inconvenient, and increases the overall volume and mass, and will also affect the intake efficiency to a certain extent. Therefore, there is a need for an engine for agricultural and forestry machinery that has a compact structure and can achieve effective dust removal. Summary of the invention

[0005] The purpose of the present invention is to solve the deficiencies of the prior art and provide a small engine for agricultural and forestry machinery.

[0006] In order to solve the above problems, the present invention adopts the following technical solutions:

[0007] A small engine for agricultural and forestry machinery comprises a piston cylinder body, an air intake seat, a carburetor and a starter; wherein the starter is drivingly connected to the piston cylinder body, the air intake seat is connected to the carburetor, and the carburetor is connected to the air intake on the piston cylinder body; the piston cylinder body comprises a crankshaft transmission structure, a left cylinder body, a right cylinder body, a sealing gasket, a combustion chamber and an ignition structure; wherein the left cylinder body and the right cylinder body are fixedly connected, and a sealing gasket matching the contour of the connecting surface is arranged on the connecting surface of the left cylinder body and the right cylinder body; a crankshaft transmission structure is arranged between the left cylinder body and the right cylinder body; the combustion chamber is fixedly arranged above the left cylinder body and the right cylinder body, and a sealing gasket is also arranged at the connecting portion between the combustion chamber and the left cylinder body and the right cylinder body; the transmission rod in the crankshaft transmission structure also extends into the combustion chamber and is connected to the piston arranged in the combustion chamber, and the transmission rod is located below the piston; an ignition structure is also arranged above the combustion chamber, and a through hole connected to the carburetor is also arranged in the upper area of ​​the piston in the combustion chamber, so that the oil mist passing through the carburetor can enter the combustion chamber; the small engine also comprises a centrifugal air intake structure;

[0008] The centrifugal air intake structure is arranged between the starter and the left cylinder body; the centrifugal structure includes a centrifugal flywheel and a guide cover; the centrifugal flywheel is fixedly arranged on the output shaft of the crankshaft transmission structure, and the centrifugal flywheel rotates with the rotation of the output shaft; the centrifugal flywheel is provided with a blade on one side facing the starter, and the other side of the centrifugal flywheel faces the left cylinder body and the combustion chamber; the guide cover is detachably fixedly connected to the piston cylinder body; an embedding hole for embedding the centrifugal flywheel is provided in the middle area of ​​the guide cover, and a gap is set between the edge of the centrifugal flywheel and the inner wall of the embedding hole on the guide cover; a guide hole penetrating the side of the guide cover is provided on the inner side of the through hole on the guide cover.

[0009] Furthermore, the crankshaft transmission structure also includes a pair of counterweights and connecting bearings; wherein the transmission rod in the crankshaft transmission structure includes a long-handled connecting shaft portion, a first connecting portion and a second connecting portion; the first connecting portion and the second connecting portion are respectively located at the two ends of the connecting shaft portion and are made integrally with the connecting shaft portion; the first connecting portion and the second connecting portion are both in the shape of a circular tube, the first connecting portion is rotationally connected to the piston in the combustion chamber, and the second connecting portion is connected to a pair of counterweights arranged in a mirror image through a roller bearing; the counterweight is overall in the shape of a long strip, one end of the counterweight is connected to the second connecting portion of the transmission rod through a roller bearing, and the other end of the counterweight is provided with a semi-cylindrical counterweight piece, and the arc surface in the counterweight piece faces the side away from the center of the counterweight; two output shafts facing away from the counterweight are respectively provided at the middle position in the length direction of the counterweight, and the two output shafts pass through the left cylinder body and the right cylinder body respectively; connecting bearings are provided between the output shaft and the left cylinder body and the right cylinder body.

[0010] Furthermore, a plurality of heat dissipation blades parallel to each other are fixedly arranged on the outer side of the combustion chamber; the heat dissipation blades are distributed at equal intervals along the axis of the cylindrical combustion chamber.

[0011] Furthermore, the centrifugal flywheel includes a flywheel seat and a plurality of blades vertically arranged on the flywheel seat; a pusher claw structure for connecting to the starter transmission is arranged in the middle area of ​​the flywheel seat, and an annular seat for connecting the blades is arranged at the edge of the flywheel seat; the annular seat is fixedly arranged on the outer periphery of the circular pusher claw structure; the annular seat includes a centrifugal area and an air intake area, and the centrifugal area and the air intake area are arranged alternately; the centrifugal area as a whole is a circular ring segment with a set angle; the air intake area as a whole is an annular conical surface segment with a set angle, and one side of the air intake area where the blades are arranged is an inclined surface, and the inclined surface is inclined from the center of the flywheel seat to the edge, so that the side close to the center of the circle is thicker and the side close to the edge is thinner; the outer diameter of the air intake area is smaller than the outer diameter of the circular ring segment.

[0012] Furthermore, a tubular protruding structure is arranged between the pusher claw structure and the annular seat, the pusher claw structure is arranged inside the protruding structure, and the annular seat is arranged outside the protruding structure.

[0013] Furthermore, the pawl structure includes a pawl structure and a toggle seat that are rotationally symmetrical about the center of the flywheel seat, and the toggle seat is made integrally with the annular seat; the pawl structure includes a pawl and a torsion spring, and the pawl is rotatably arranged on the connecting column of the toggle seat; the two ends of the torsion spring are respectively connected to the toggle seat and the clamping pawl; a connecting hole for connecting the output shaft is provided in the center of the toggle seat; and a ratchet that cooperates with the pawl structure is provided on the starter.

[0014] Furthermore, the inner side wall of the protruding structure is also provided with an arc surface opening which fits with the outer side surface of the pawl.

[0015] Furthermore, a rotating pin for clamping is provided between the output rotating shaft and the toggle seat; the rotating pin protrusion is provided on the outer side surface of the output rotating shaft, and the rotating pin is also embedded in the toggle seat.

[0016] Furthermore, the starter also includes a pull rope drum, a coil spring is arranged between the pull rope drum and the shell; the shell is fixedly arranged on the piston cylinder body; a pull rope is arranged on the pull rope drum, and the other end of the pull rope passes through the shell and is connected to the handle outside the shell; the pull rope drum is also connected to the ratchet transmission; and a vent is arranged on the shell.

[0017] Furthermore, a plurality of raised clamping columns are provided on the side of the air deflector facing the piston cylinder body, and a corresponding cylindrical hole is provided on the piston cylinder body; an air deflector hole is provided on the upper edge of the air deflector; a hollow air supply channel is also provided on the piston cylinder body; one end of the air supply channel is connected to the air supply hole provided on the air deflector, and a side hole corresponding to the air supply hole is provided on the shell, and the direction of the side hole is different from that of the air deflector hole on the air deflector; the air supply hole and the air deflector hole provided on the air deflector are respectively located in different edge areas of the air deflector; the other end of the air supply channel leads to the space where the air intake seat above the piston cylinder body is located.

[0018] The beneficial effects of the present invention are:

[0019] By setting up a structure with a simple crankshaft transmission structure, combustion chamber, ignition structure and centrifugal intake structure, the engine components are simplified while meeting the functional requirements of the engine, making the structure compact, the overall volume small and the weight light;

[0020] By setting the crankshaft transmission structure including the mirror-imaged counterweight block and the overall shape of the counterweight block, the transmission rod can drive the counterweight block to rotate more smoothly while moving up and down, so that the output shaft can rotate stably and reduce shaking;

[0021] By arranging a number of heat dissipation panels on the outside of the combustion chamber and cooperating with a centrifugal flywheel, the airflow can quickly pass through the area between the heat dissipation panels, taking away the heat thereon, thus ensuring that the combustion chamber can work normally for a long time;

[0022] By setting a centrifugal flywheel in conjunction with a deflector, air intake is achieved while some impurities are thrown out of the internal space of the engine through the deflector holes provided on the deflector, thereby reducing the accumulation of dust and impurities inside the engine. On the one hand, it keeps the engine clean, and on the other hand, it reduces safety hazards and increases service life.

[0023] By setting a centrifugal area and an air intake area on the edge of the flywheel seat of the centrifugal flywheel, the centrifugal area focuses on discharging impurities in the air from the engine, while the air intake area takes into account both the discharge of impurities and the intake of air, thereby achieving air intake and dust removal at the same time;

[0024] By arranging a ratchet and a pawl structure between the centrifugal flywheel and the starter to cooperate, the two can rotate simultaneously in a set direction, and do not interfere with each other in the other direction, so that the starter can drive the output shaft through the centrifugal flywheel, and at the same time, when the output shaft continues to rotate, it will not interfere with the starter;

[0025] By setting up an air supply channel in conjunction with the air supply hole and the side hole, the air entering the intake seat is ensured to be relatively clean, without the need to add additional structures such as an air filter, thereby reducing the size and weight of the engine. BRIEF DESCRIPTION OF THE DRAWINGS

[0026] Figure 1 The overall structure of Example 1 explodes Figure 1 ;

[0027] Figure 2 for Figure 1 A local enlarged view of area A;

[0028] Figure 3 It is a right side view of the overall structure of Example 1;

[0029] Figure 4 It is a front view of the overall structure of Example 1;

[0030] Figure 5 It is a top view of the overall structure of Example 1;

[0031] Figure 6 The overall structure of Example 1 explodes Figure 2 ;

[0032] Figure 7 Schematic diagram of the crankshaft transmission structure and sealing gasket of Example 1;

[0033] Figure 8 Schematic diagram of the crankshaft transmission structure of Example 1;

[0034] Fig. 9 is a schematic diagram of the overall structure of Example 1;

[0035] Fig.10 Schematic diagram of the centrifugal flywheel of Example 1 Figure 1 ;

[0036] Fig.11 Schematic diagram of the centrifugal flywheel of Example 1 Figure 2 ;

[0037] Fig.12 Schematic diagram of the ratchet of Example 1;

[0038] Fig.13 This is a schematic diagram of the air deflector of Example 1.

[0039] Description of the symbols in the accompanying drawings: piston cylinder body 1, output shaft 11, rotating pin 12, crankshaft transmission structure 13, counterweight 131, connecting bearing 132, transmission rod 133, connecting shaft part 1331, first connecting part 1332, second connecting part 1333, left cylinder body 14, air supply channel 141, right cylinder body 15, sealing gasket 16, combustion chamber 17, heat dissipation plate 171, ignition structure 18, intake seat 2, carburetor 3, starter 4, intake structure 41, shell 42, side hole 421, handle 43, ratchet 44, centrifugal flywheel 5, flywheel seat 51, centrifugal area 511, intake area 512, blades 52, pawl structure 53, pawl structure 531, toggle seat 532, arc surface mouth 533, protrusion structure 54, deflector 6, deflector hole 61, hook structure 62, air supply hole 63. DETAILED DESCRIPTION

[0040] The following describes the embodiments of the present invention by specific examples, and those skilled in the art can easily understand other advantages and effects of the present invention from the contents disclosed in this specification. The present invention can also be implemented or applied through other different specific embodiments, and the details in this specification can also be modified or changed in various ways based on different viewpoints and applications without departing from the spirit of the present invention. It should be noted that the following embodiments and features in the embodiments can be combined with each other without conflict.

[0041] It should be noted that the illustrations provided in the following embodiments are only used to schematically illustrate the basic concept of the present invention. The figures only show components related to the present invention rather than being drawn according to the number, shape and size of components in actual implementation. In actual implementation, the type, quantity and proportion of each component may be changed arbitrarily, and the component layout may also be more complicated.

[0042] Embodiment 1:

[0043] like Figure 1 to Figure 13 As shown, a small engine for agricultural and forestry machinery includes a piston cylinder body 1, an intake seat 2, a carburetor 3 and a starter 4; wherein the starter 4 is connected to the piston cylinder body 1 in a driving manner, the intake seat 2 is connected to the carburetor 3, and the carburetor 3 is connected to the intake port on the piston cylinder body 1; the piston cylinder body includes a crankshaft transmission structure 13, a left cylinder body 14, a right cylinder body 15, a sealing gasket 16, a combustion chamber 17 and an ignition structure 18; wherein the left cylinder body 14 and the right cylinder body 15 are fixedly connected, and a sealing gasket 16 matching the contour of the connecting surface is provided on the connecting surface of the left cylinder body 14 and the right cylinder body 15; the left cylinder body 14 and the right cylinder body 15 are connected to each other. A crankshaft transmission structure 13 is arranged between the left cylinder body 14 and the right cylinder body 15; a combustion chamber 17 is fixedly arranged above the left cylinder body 14 and the right cylinder body 15, and a sealing gasket 16 is also arranged at the connection part between the combustion chamber 17 and the left cylinder body 14 and the right cylinder body 15; a transmission rod 133 in the crankshaft transmission structure 13 also extends into the combustion chamber 17, and is connected to a piston arranged in the combustion chamber 17, and the transmission rod 133 is located below the piston; an ignition structure 18 is also arranged above the combustion chamber 17, and a through hole connected to the carburetor is also arranged in the upper area of ​​the piston in the combustion chamber 17, so that the oil mist passing through the carburetor can enter the combustion chamber 17; the small engine also includes a centrifugal intake structure. A single combustion chamber 17 is arranged to be directly connected to the left cylinder body 14 or the right cylinder body 15, and cooperates with the crankshaft transmission structure 13 to control the rotation of the output shaft, so as to realize the basic functions of the engine with a compact structure.

[0044] The small engine also includes a centrifugal structure; the centrifugal structure is arranged between the starter 4 and the piston cylinder body 1; the centrifugal structure includes a centrifugal flywheel 5 and a shroud 6; wherein the centrifugal flywheel 5 is fixedly arranged on the output shaft 11 of the piston cylinder body 1, and the centrifugal flywheel 5 rotates with the rotation of the output shaft 11; the other end of the output shaft 11 passes through the piston cylinder body 1 and is transmission-connected to an external component, such as a wheel or a lawn mower fan, etc.; the shroud 6 is detachably fixedly connected to the piston cylinder body 1; a through hole for placing the centrifugal flywheel 5 is arranged in the middle area of ​​the shroud 6, and a gap is set between the edge of the centrifugal flywheel 5 and the inside of the through hole on the shroud 6, In this example, the setting value range of the gap is 2mm~5mm to reduce the possibility of impurities passing through the gap and entering the piston cylinder body 1; the inner side of the through hole on the deflector 6 is provided with a guide hole 61 that passes through the side of the deflector 6. In this example, the guide hole 61 is a larger open area above the deflector 6; wherein the bottom and left and right sides of the deflector 6 are in contact with the piston cylinder body 1, leaving only an open gap at the top, so that the centrifugal flywheel 5 can use the centrifugal force generated by the rotation to throw dust and other impurities out of the centrifugal structure through the guide hole 61 during the rotation, and pump the centrifugally purified air into the area where the combustion chamber 17 is located.

[0045] The crankshaft transmission structure 13 also includes a pair of counterweights 131 and a connecting bearing 132; wherein the transmission rod 133 in the crankshaft transmission structure 13 includes a long handle-shaped connecting shaft portion 1331, a first connecting portion 1332 and a second connecting portion 1333; the first connecting portion 1332 and the second connecting portion 1333 are respectively located at both ends of the connecting shaft portion 1331 and are integrally formed with the connecting shaft portion 1331; the first connecting portion 1332 and the second connecting portion 1333 are both in the shape of a circular tube, the first connecting portion 1332 is rotatably connected to the piston in the combustion chamber 17, and the second connecting portion 1333 is connected to a pair of mirror-image-shaped connecting shaft portions 1331 and 1333; The counterweight 131 is connected through a roller bearing; the counterweight 131 is in the shape of a long strip as a whole, one end of the counterweight 131 is connected to the second connection part 1333 of the transmission rod 133 through a roller bearing, and the other end of the counterweight 131 is provided with a semi-cylindrical counterweight, and the arc surface of the counterweight faces the side away from the center of the counterweight 131; two output shafts facing away from the counterweight 131 are respectively provided at the middle position in the length direction of the counterweight 131, and the two output shafts pass through the left cylinder body 14 and the right cylinder body 15 respectively; a connecting bearing 132 is provided between the output shaft and the left cylinder body 14 and the right cylinder body 15. By providing the counterweight, the center of gravity of the counterweight 131 is as close to the center as possible, so that the counterweight 131 does not generate a large centrifugal force when rotating, and reduces the vibration of the engine when working.

[0046] A plurality of heat sinks 171 parallel to each other are fixedly arranged outside the combustion chamber 17; the heat sinks 171 are evenly spaced along the axis of the cylindrical combustion chamber 17. The upper portion of the centrifugal flywheel corresponds to the area of ​​the heat sinks 171 outside the combustion chamber 17.

[0047] The centrifugal flywheel 5 comprises a flywheel seat 51 and a plurality of blades 52 vertically arranged on the flywheel seat 51. The overall shape of the blades 52 is an arc-shaped long sheet. One end of the blades 52 is fixedly connected to the flywheel seat 51, and the edge of the end surface of the other end is provided with a rounded structure. The rounded structure is more solid and reduces the deformation caused by the collision between the edge of the blade 52 and impurities and debris. The middle area of ​​the flywheel seat 51 is provided with a pusher claw structure 53 for transmission connection with the starter 4, and the edge of the flywheel seat 51 is provided with an annular seat for connecting the blades 52. The annular seat is fixedly arranged on the outer periphery of the circular pusher claw structure 53; the annular seat includes a centrifugal area 511 and an air intake area 512, and the centrifugal area 511 and the air intake area 512 are arranged alternately; the centrifugal area 511 as a whole is a circular ring segment with a set angle; the air intake area 512 as a whole is an annular conical surface segment with a set angle, and the side of the air intake area 512 provided with the blade 52 is an inclined surface, and the inclined surface is inclined from the center of the flywheel seat 51 to the edge, so that the side close to the center is thicker and the side close to the edge is thinner; the outer diameter of the air intake area 512 is smaller than the outer diameter of the circular ring segment. In the centrifugal area 511 of the annular seat, the outer edge of the circular ring segment is close to the inner wall of the through hole on the air guide cover 6, making it difficult for the debris in this part to pass through, and can only leave the device through the air guide hole 61 as the centrifugal flywheel 5 rotates; and in the air intake area 512 of the annular seat, due to the design of the annular conical surface segment, the air flow can enter the piston cylinder body 1 along the air intake area 512, and the outer diameter of the air intake area 512 is smaller than the outer diameter of the circular ring segment, which means that the gap between the outer edge of the air intake area 512 and the inside of the through hole of the air guide cover 6 is larger, which is convenient for the air flow to pass; it should be noted that some impurities in the air intake area 512 will also leave the device as the centrifugal force of the rotation of the centrifugal flywheel 5. In addition, in this example, the edge of the blade 52 extends out of the outer edge of the air intake area 512, so that the blade 52 is larger as a whole, increasing the air intake efficiency of the centrifugal flywheel 5.

[0048] A tubular protruding structure 54 is provided between the claw structure 53 and the annular seat. The claw structure 53 is provided inside the protruding structure 54 , and the annular seat is provided outside the protruding structure 54 . In this example, the annular seat and the protruding structure 54 are made in one piece.

[0049] The pawl structure 53 includes a pawl structure 531 and a toggle seat 532 which are rotationally symmetrical about the center of the flywheel seat 51. In this example, the toggle seat 532 is made integrally with the annular seat. The pawl structure 531 includes a pawl and a torsion spring. The pawl is rotatably arranged on the connecting column of the toggle seat 532. The two ends of the torsion spring are respectively connected to the toggle seat 532 and the clamping pawl. The center of the toggle seat 532 is provided with a connecting hole for connecting the output shaft 11. The starter 4 is provided with a ratchet wheel 44 which cooperates with the pawl structure 531. The toggle seat 532 is provided with two pawls. When the pawl and the ratchet wheel 44 are engaged and matched, the internal structure of the starter 4 can rotate with the centrifugal flywheel 5. When the pawl and the ratchet wheel 44 are engaged and matched, the internal structure of the starter 4 can rotate together with the centrifugal flywheel 5. When the pawl and the ratchet wheel 44 are engaged and matched, the internal structure of the starter 4 rotates while the centrifugal flywheel 5 stops rotating in the other rotation direction. In addition, when the centrifugal flywheel 5 rotates with the output shaft 11, it will not drive the internal structure of the starter 4 to rotate.

[0050] The inner wall of the protruding structure 54 is also provided with an arcuate opening 533 which fits with the outer side surface of the pawl. The arcuate opening 533 forms a certain restriction on the rotation of the pawl, thereby reducing the load generated by the pawl on the connecting column during the rotation process.

[0051] A rotating pin 12 for clamping is also provided between the output shaft 11 and the toggle seat 532 . The rotating pin protrusion is provided on the outer side surface of the output shaft, and the rotating pin is also embedded in the connecting hole on the toggle seat 532 to ensure that the toggle seat 532 can rotate with the rotation of the output shaft 11 .

[0052] An air intake structure 41 is provided on the shell 42 of the starter 4, and the air intake structure 41 includes a plurality of air vents; the air intake structure 41 is directly opposite to the centrifugal flywheel 5; in this example, the air vents are in the shape of arc-shaped strips, through which air flow is achieved.

[0053] The starter 4 also includes a shell 42 and a rope pull drum, and a coil spring is arranged between the rope pull drum and the shell 42 to help the rope pull drum reset, one end of the coil spring is connected to the shell 42, and the other end of the shell 42 is connected to the rope pull drum; the shell 42 is fixedly arranged on the piston cylinder body 1; a rope is arranged on the rope pull drum, and the other end of the rope passes through the shell 42 and is connected to the handle 43 outside the shell 42; the rope pull drum is also connected to the ratchet 44 in transmission; a vent is arranged on the shell 42.

[0054] The air deflector 6 is provided with a plurality of raised clamping columns on the side facing the piston cylinder body 1, and a corresponding cylindrical hole is provided on the piston cylinder body 1; the upper edge of the air deflector 6 is provided with a deflection hole 61; the upper edge of the air deflector 6 is also provided with a hook structure 62 for clamping the oil supply pipeline on the piston cylinder body 1. Buckling the oil supply pipeline on the hook structure 62 can reduce the shaking amplitude of the oil supply pipeline caused by the operation of the engine. A hollow air supply channel 141 is also provided on the piston cylinder body; one end of the air supply channel 141 is connected to the air supply hole 63 provided on the air deflector, and a side hole 421 corresponding to the air supply hole 63 is provided on the shell, and the direction of the side hole 421 is different from the direction of the air deflector hole on the air deflector; the air supply hole 63 and the air deflector hole provided on the air deflector are respectively located in different edge areas of the air deflector; the other end of the air supply channel 141 leads to the space where the air intake seat is located above the piston cylinder body, so that the air entering the air intake seat is the relatively clean air entering through the side hole 421, because in this example the air intake seat is arranged upward, and there are some dust and debris centrifugally discharged by the centrifugal flywheel above, which will affect the cleanliness of the gas entering the air intake seat, so it is necessary to set the side hole 421 for air intake, and cooperate with the centrifugal flywheel to allow clean air to enter the area where the air intake seat is located.

[0055] During the implementation process, by setting up a simple crankshaft transmission structure 13 and a combustion chamber 17, an ignition structure 18 and a centrifugal intake structure, etc., while meeting the functional requirements of the engine, the components of the engine are simplified to make the structure compact, the overall volume small and the weight light; by setting the crankshaft transmission structure 13 including the mirror-set counterweight block 131 and the overall shape of the counterweight block 131, the transmission rod 133 can drive the counterweight block 131 to rotate more smoothly while moving up and down, so that the output shaft can rotate stably and reduce shaking; by setting a number of heat dissipation panels 171 on the outside of the combustion chamber 17, in conjunction with the centrifugal flywheel, the airflow can quickly pass through the area between the heat dissipation panels 171, take away the heat thereon, and ensure that the combustion chamber 17 can work normally for a long time; by setting the centrifugal flywheel 5 in conjunction with the deflector 6, while achieving air intake, some impurities are thrown out of the engine through the deflection holes 61 set on the deflector 6. The internal space of the engine is reduced to reduce the accumulation of impurities inside the engine, which not only keeps it clean, but also reduces safety hazards and increases its service life; by setting a centrifugal area 511 and an air intake area 512 on the edge of the flywheel seat 51 of the centrifugal flywheel 5, the centrifugal area 511 focuses on discharging impurities in the air from the engine, and the air intake area 512 takes into account both the discharge of impurities and the intake of air, thereby achieving air intake and dust removal at the same time; by setting a ratchet 44 and a pawl structure between the centrifugal flywheel 5 and the starter 4 for coordination, the two can rotate simultaneously in a set direction, and in the other direction, they do not interfere with each other, so that the starter 4 can drive the output shaft 11 through the centrifugal flywheel 5, and when the output shaft 11 continues to rotate, it will not interfere with the starter 4; by setting an air supply channel 141 to cooperate with the air supply hole 63 and the side hole 421, it is ensured that the air entering the air intake seat is relatively clean, without the need to add additional structures such as air filters, thereby reducing the volume and mass of the engine.

[0056] The above description is only a specific example of the present invention and does not constitute any limitation to the present invention. It is obvious that for professionals in this field, after understanding the content and principle of the present invention, various modifications and changes in form and details may be made without departing from the principle and structure of the present invention, but these modifications and changes based on the idea of ​​the present invention are still within the scope of protection of the claims of the present invention.

Claims

1. A small engine for agricultural and forestry machinery, comprising a piston cylinder body (1), an air intake seat (2), a carburetor (3) and a starter (4); wherein the starter (4) is drivingly connected to the piston cylinder body (1), the air intake seat (2) is connected to the carburetor (3), and the carburetor (3) is connected to an air intake port on the piston cylinder body (1); characterized in that: The piston cylinder body comprises a crankshaft transmission structure (13), a left cylinder block (14), a right cylinder block (15), a sealing gasket (16), a combustion chamber (17), and an ignition structure (18); wherein the left cylinder block (14) and the right cylinder block (15) are fixedly connected, and a sealing gasket (16) matching the contour of the connection surface is arranged on the connection surface of the left cylinder block (14) and the right cylinder block (15); a crankshaft transmission structure (13) is arranged between the left cylinder block (14) and the right cylinder block (15); the combustion chamber (17) is fixedly arranged above the left cylinder block (14) and the right cylinder block (15); 17) and the connection parts with the left cylinder body (14) and the right cylinder body (15) are also provided with sealing gaskets (16); the transmission rod (133) in the crankshaft transmission structure (13) also extends into the combustion chamber (17) and is connected to a piston arranged in the combustion chamber (17), and the transmission rod (133) is located below the piston; an ignition structure (18) is also provided above the combustion chamber (17), and a through hole connected to a carburetor is also provided in the upper area of ​​the piston in the combustion chamber (17), so that oil mist passing through the carburetor can enter the combustion chamber (17); the small engine also includes a centrifugal intake structure; The centrifugal air intake structure is arranged between the starter (4) and the left cylinder body (14); the centrifugal structure comprises a centrifugal flywheel (5) and a flow guide cover (6); wherein the centrifugal flywheel (5) is fixedly arranged on the output shaft (11) of the crankshaft transmission structure (13), and the centrifugal flywheel (5) rotates following the rotation of the output shaft (11); the side of the centrifugal flywheel provided with blades faces the starter, and the other side of the centrifugal flywheel faces the left cylinder body (14) and the combustion chamber (17); the flow guide cover (6) is detachably fixedly connected to the piston cylinder body (1); an embedding hole for embedding the centrifugal flywheel (5) is arranged in the middle area of ​​the flow guide cover (6), and a gap is set between the edge of the centrifugal flywheel (5) and the inner wall of the embedding hole on the flow guide cover (6); a flow guide hole (61) penetrating the side of the flow guide cover (6) is arranged inside the through hole on the flow guide cover (6); The centrifugal flywheel (5) comprises a flywheel seat (51) and a plurality of blades (52) vertically arranged on the flywheel seat (51); a pusher claw structure (53) for transmission connection with a starter (4) is arranged in the middle area of ​​the flywheel seat (51); an annular seat for connecting the blades (52) is arranged at the edge of the flywheel seat (51); the annular seat is fixedly arranged on the outer periphery of the circular pusher claw structure (53); the annular seat comprises a centrifugal area (511) and an air intake area (512), and the centrifugal area (511) and the air intake area (512) are arranged alternately; the centrifugal area (511) as a whole is a circular ring segment with a set angle; the air intake area (512) as a whole is an annular conical surface segment with a set angle; a side of the air intake area (512) provided with the blades (52) is an inclined surface, and the inclined surface is inclined from the center of the flywheel seat (51) to the edge, so that the side close to the center is thicker and the side close to the edge is thinner; the outer diameter of the air intake area (512) is smaller than the outer diameter of the circular ring segment.

2. A small engine for agricultural and forestry machinery according to claim 1, characterized in that: The crankshaft transmission structure (13) further comprises a pair of counterweights (131) and a connecting bearing (132); wherein the transmission rod (133) in the crankshaft transmission structure (13) comprises a long-handled connecting shaft portion (1331), a first connecting portion (1332) and a second connecting portion (1333); the first connecting portion (1332) and the second connecting portion (1333) are respectively located at two ends of the connecting shaft portion (1331) and are integrally formed with the connecting shaft portion (1331); the first connecting portion (1332) and the second connecting portion (1333) are both in the shape of a circular tube; the first connecting portion (1332) is rotatably connected to a piston in a combustion chamber (17); and the second connecting portion (1333) is mirror-imaged to the first connecting portion (1332). A pair of counterweight blocks (131) are connected via a roller bearing; the counterweight block (131) is in the shape of an elongated strip as a whole; one end of the counterweight block (131) is connected to a second connecting portion (1333) of a transmission rod (133) via a roller bearing; a semi-cylindrical counterweight piece is provided at the other end of the counterweight block (131); an arc surface in the counterweight piece faces a side away from the center of the counterweight block (131); two output rotating shafts facing away from the counterweight block (131) are respectively provided at the middle position in the length direction of the counterweight block (131); the two output rotating shafts respectively pass through the left cylinder body (14) and the right cylinder body (15); and connecting bearings (132) are provided between the output rotating shafts and the left cylinder body (14) and the right cylinder body (15).

3. A small engine for agricultural and forestry machinery according to claim 1, characterized in that: A plurality of mutually parallel heat dissipation panels (171) are fixedly arranged on the outside of the combustion chamber (17); the heat dissipation panels (171) are distributed at equal intervals along the axis of the cylindrical combustion chamber (17).

4. A small engine for agricultural and forestry machinery according to claim 1, characterized in that: A tubular protruding structure (54) is provided between the pusher claw structure (53) and the annular seat, the pusher claw structure (53) is provided inside the protruding structure (54), and the annular seat is provided outside the protruding structure (54).

5. A small engine for agricultural and forestry machinery according to claim 4, characterized in that: The pawl structure (53) comprises a pawl structure (531) and a toggle seat (532) which are rotationally symmetrical about the center of a flywheel seat (51); the toggle seat (532) is made integrally with the annular seat; the pawl structure (531) comprises a pawl and a torsion spring; the pawl is rotatably arranged on a connecting column of the toggle seat (532); the two ends of the torsion spring are respectively connected to the toggle seat (532) and the clamping pawl; a connecting hole for connecting to an output shaft (11) is arranged at the center of the toggle seat (532); and a ratchet wheel which cooperates with the pawl structure (531) is arranged on the starter (4).

6. A small engine for agricultural and forestry machinery according to claim 5, characterized in that: The inner side wall of the protruding structure (54) is also provided with an arc surface opening (533) that fits with the outer side surface of the pawl.

7. A small engine for agricultural and forestry machinery according to claim 5, characterized in that: A rotating pin (12) for clamping is also provided between the output rotating shaft (11) and the toggle seat (532); the rotating pin protrudes on the outer side of the output rotating shaft, and the rotating pin is also embedded in the toggle seat.

8. The small engine for agricultural and forestry machinery according to claim 5, characterized in that: The starter (4) further comprises a pull rope drum, wherein a coil spring is arranged between the pull rope drum and the housing (42); the housing (42) is fixedly arranged on the piston cylinder body (1); a pull rope is arranged on the pull rope drum, and the other end of the pull rope passes through the housing (42) and is connected to a handle (43) outside the housing (42); the pull rope drum is also connected to the ratchet transmission; and a vent hole is arranged on the housing (42).

9. A small engine for agricultural and forestry machinery according to claim 8, characterized in that: The air deflector (6) is provided with a plurality of protruding clamping columns on one side facing the piston cylinder body (1), and the piston cylinder body (1) is provided with a columnar hole corresponding thereto; an air deflector hole (61) is provided on the upper edge of the air deflector (6); a hollow air supply channel (141) is also provided on the piston cylinder body; one end of the air supply channel (141) is connected to the air supply hole (63) provided on the air deflector, and a side hole (421) corresponding to the air supply hole (63) is provided on the shell, and the direction of the side hole (421) is different from that of the air deflector hole on the air deflector; the air supply hole (63) and the air deflector hole provided on the air deflector are respectively located in different edge areas of the air deflector; the other end of the air supply channel (141) leads to the space where the air inlet seat is located above the piston cylinder body.

Images