阅读说明：本技术 适于活塞式二冲程航空发动机的曲轴总成 (Crankshaft assembly suitable for piston type two-stroke aircraft engine ) 是由 李为松 李康 夏志远 方芳 于 2019-11-05 设计创作，主要内容包括：本发明公开了一种适于活塞式二冲程航空发动机的曲轴总成,包括曲轴本体、主轴承和辅助轴承,主轴承和辅助轴承为自润滑深沟球轴承,曲轴本体包括曲轴前曲柄、曲轴后曲柄以及与曲轴前曲柄和曲轴后曲柄连接的曲轴连接曲柄臂,曲轴前曲柄上套设有辅助轴承和一主轴承,曲轴后曲柄上套设有另一主轴承。本发明适于活塞式二冲程航空发动机的曲轴总成,主轴承和辅助轴承都是采用自润滑的深沟球轴承,主轴承和辅助轴承的润滑不需要消耗二冲程发动机的混合油,从而可以降低发动机的油耗,同时自润滑轴承自身是密封的,受到外界影响小,轴承的可靠性有保障。(The invention discloses a crankshaft assembly suitable for a piston type two-stroke aero-engine, which comprises a crankshaft body, a main bearing and an auxiliary bearing, wherein the main bearing and the auxiliary bearing are self-lubricating deep groove ball bearings, the crankshaft body comprises a crankshaft front crank, a crankshaft rear crank and a crankshaft connecting crank arm connected with the crankshaft front crank and the crankshaft rear crank, the auxiliary bearing and the main bearing are sleeved on the crankshaft front crank, and the other main bearing is sleeved on the crankshaft rear crank. The self-lubricating bearing is sealed, is slightly influenced by the outside and ensures the reliability of the bearing.)

1. Be suitable for piston two-stroke aeroengine's crankshaft assembly, its characterized in that: including bent axle body, main bearing and auxiliary bearing are self-lubricating deep groove ball bearing, and the bent axle body includes crank before the bent axle, crank behind the bent axle and with the bent axle before the bent axle crank and the bent axle crank connection crank arm of being connected behind the crank, the cover is equipped with auxiliary bearing and a main bearing before the bent axle on the crank, the cover is equipped with another main bearing behind the bent axle on the crank.

2. A crankshaft assembly for a piston-type two-stroke aircraft engine according to claim 1, wherein: the crank shaft front crank comprises a front shaft body, a front crank arm connected with the front shaft body and a front connecting rod neck connected with the front crank arm and connected with the crank shaft connecting crank arm, wherein a connecting rod bearing is sleeved on the front connecting rod neck, the connecting rod bearing is positioned between the crank shaft connecting crank arm and the front crank arm, and the connecting rod bearing is a needle bearing.

3. A crankshaft assembly for a piston-type two-stroke aircraft engine according to claim 2, wherein: the front connecting rod neck is provided with a front oil storage groove for containing a lubricating medium and a front lubricating oil hole for leading the lubricating medium in the front oil storage groove to the connecting rod bearing, and the vertical distance between the front lubricating oil hole and the axis of the front shaft body is larger than the vertical distance between the axis of the front connecting rod neck and the axis of the front shaft body.

4. A crankshaft assembly for a piston-type two-stroke aircraft engine according to claim 3, wherein: the front crank arm is provided with a front plug hole communicated with the front oil storage tank, a front plug is arranged in the front plug hole, and the front oil storage tank extends along the axial direction of the front connecting rod neck.

5. A crankshaft assembly for a piston-type two-stroke aircraft engine according to any one of claims 2 to 4, wherein: the front shaft body is configured for mounting a propeller, the front shaft body having a front contact surface located in the central bore of the propeller and in contact with the propeller, the front contact surface being a conical surface.

6. A crankshaft assembly for a two-stroke aircraft engine according to any one of claims 1 to 5, wherein: the crank behind the bent axle includes the back axis body, with the back crank arm of back axis body coupling and with back crank arm coupling and with the back connecting rod neck that the crank arm is connected to the bent axle, the cover is equipped with a connecting rod bearing on the back connecting rod neck, the connecting rod bearing is located between bent axle coupling crank arm and the back crank arm and the connecting rod bearing is needle bearing.

7. A crankshaft assembly for a two-stroke aircraft engine according to claim 6, wherein: the rear connecting rod neck is provided with a rear oil storage groove for containing a lubricating medium and a rear lubricating oil hole for leading the lubricating medium in the rear oil storage groove to the connecting rod bearing, and the vertical distance between the rear lubricating oil hole and the axis of the rear shaft body is larger than the vertical distance between the axis of the rear connecting rod neck and the axis of the rear shaft body.

8. A crankshaft assembly for a two-stroke aircraft engine according to claim 7, wherein: the rear crank arm is provided with a rear plug hole communicated with the rear oil storage tank, a rear plug is arranged in the rear plug hole, and the rear oil storage tank extends along the axial direction of the rear connecting rod neck.

9. A crankshaft assembly for a two-stroke aircraft engine according to any one of claims 6 to 8, wherein: and a signal tooth positioning surface and a signal tooth threaded hole are arranged on the crankshaft rear crank.

10. A crankshaft assembly for a two-stroke aircraft engine according to any one of claims 1 to 8, wherein: and an oil pump driving cam is arranged on the crankshaft front crank and is positioned between the main bearing and the auxiliary bearing.

Technical Field

The invention belongs to the technical field of engines, and particularly relates to a crankshaft assembly suitable for a piston type two-stroke aero-engine.

Background

At present, in the field of piston type two-stroke aero-engines, a crankshaft assembly is taken as the most important engine body part of the engine, and the crankshaft assembly has the function of converting gas acting force transmitted by a piston connecting rod group into rotating torque of a crankshaft to be output outwards and driving a gas distribution mechanism and other auxiliary devices of the engine to work. The requirements of an airplane on a power assembly are high power and low oil consumption, a small piston type two-stroke engine generally adopts an engine to directly drive a propeller, the weight reduction of the engine is particularly important, and a crankshaft occupies a large part of weight, so the weight reduction of the crankshaft is taken as important research content of the weight reduction of the engine.

The two-stroke small-sized aeroengine has the advantage of high power-weight ratio, but has the defect of high oil consumption. The crankcase of a two-stroke engine is used for engine intake, so that oil cannot be stored like a four-stroke engine, and the two-stroke engine is lubricated by the following method: the oil is first mixed with fuel to introduce the mixture into the crankcase, lubricating the connecting rod journal bearing and crankshaft main bearings. The fuel oil and the lubricating oil in the two-stroke gasoline engine have a certain proportion, the fuel oil is used for combustion, the engine oil is used for lubrication, and the oil consumption is increased by the excessive mixed oil.

Disclosure of Invention

The present invention is directed to solving at least one of the problems of the prior art. Therefore, the invention provides a crankshaft assembly suitable for a small-sized piston type two-stroke aircraft engine, and aims to reduce the oil consumption of the engine.

In order to achieve the purpose, the invention adopts the technical scheme that: be suitable for piston two-stroke aeroengine's crankshaft assembly, including bent axle body, main bearing and auxiliary bearing are self-lubricating deep groove ball bearing, and the bent axle body includes crank before the bent axle, crank behind the bent axle and with the bent axle before the bent axle crank and the crank connection crank arm that the crank is connected behind the bent axle, the cover is equipped with auxiliary bearing and a main bearing before the bent axle on the crank, the cover is equipped with another main bearing behind the bent axle on the crank.

The crank shaft front crank comprises a front shaft body, a front crank arm connected with the front shaft body and a front connecting rod neck connected with the front crank arm and connected with the crank shaft connecting crank arm, wherein a connecting rod bearing is sleeved on the front connecting rod neck, the connecting rod bearing is positioned between the crank shaft connecting crank arm and the front crank arm, and the connecting rod bearing is a needle bearing.

The front connecting rod neck is provided with a front oil storage groove for containing a lubricating medium and a front lubricating oil hole for leading the lubricating medium in the front oil storage groove to the connecting rod bearing, and the vertical distance between the front lubricating oil hole and the axis of the front shaft body is larger than the vertical distance between the axis of the front connecting rod neck and the axis of the front shaft body.

The front crank arm is provided with a front plug hole communicated with the front oil storage tank, a front plug is arranged in the front plug hole, and the front oil storage tank extends along the axial direction of the front connecting rod neck.

The front shaft body is configured for mounting a propeller, the front shaft body having a front contact surface located in the central bore of the propeller and in contact with the propeller, the front contact surface being a conical surface.

The crank behind the bent axle includes the back axis body, with the back crank arm of back axis body coupling and with back crank arm coupling and with the back connecting rod neck that the crank arm is connected to the bent axle, the cover is equipped with a connecting rod bearing on the back connecting rod neck, the connecting rod bearing is located between bent axle coupling crank arm and the back crank arm and the connecting rod bearing is needle bearing.

The rear connecting rod neck is provided with a rear oil storage groove for containing a lubricating medium and a rear lubricating oil hole for leading the lubricating medium in the rear oil storage groove to the connecting rod bearing, and the vertical distance between the rear lubricating oil hole and the axis of the rear shaft body is larger than the vertical distance between the axis of the rear connecting rod neck and the axis of the rear shaft body.

The rear crank arm is provided with a rear plug hole communicated with the rear oil storage tank, a rear plug is arranged in the rear plug hole, and the rear oil storage tank extends along the axial direction of the rear connecting rod neck.

And a signal tooth positioning surface and a signal tooth threaded hole are arranged on the crankshaft rear crank.

And an oil pump driving cam is arranged on the crankshaft front crank and is positioned between the main bearing and the auxiliary bearing.

The self-lubricating bearing is sealed, is slightly influenced by the outside and ensures the reliability of the bearing.

Drawings

The description includes the following figures, the contents shown are respectively:

FIG. 1 is a cross-sectional view of a crankshaft assembly of the present invention suitable for use in a piston-type two-stroke aircraft engine;

FIG. 2 is a schematic view of the construction of a front axle body;

FIG. 3 is a schematic structural view of the rear axle body;

FIG. 4 is a schematic view of the structure of a crankshaft connecting crank arm;

fig. 5 is a schematic structural view of an oil pump driving cam;

labeled as: 1. a crankshaft front crank; 2. an auxiliary bearing; 3. an oil pump drive cam; 4. a main bearing; 5. front pipe plug; 6. a connecting rod bearing; 7. the crank shaft is connected with the crank arm; 8. a lubricating medium; 9. front blocking; 10. a crankshaft rear crank; 101. a front contact face; 102. plugging the hole with the front thread; 103. a front lubrication oil hole; 104. a front oil storage tank; 105. removing heavy holes; 106. a front axle body; 107. a front crank arm; 108. a front connecting rod neck; 1001. a rear contact surface; 1002. plugging the hole with the rear thread; 1003. a rear lubrication oil hole; 1004. removing heavy holes; 1005. signal tooth threaded holes; 1006. a signal tooth positioning surface; 1007. a rear axle body; 1008. a rear crank arm; 1009. a rear connecting rod neck.

Detailed Description

The following detailed description of the embodiments of the present invention will be given with reference to the accompanying drawings for a purpose of helping those skilled in the art to more fully, accurately and deeply understand the concept and technical solution of the present invention and to facilitate its implementation.

It should be noted that, in the following embodiments, the terms "first", "second" and "third" do not denote absolute differences in structure and/or function, nor do they denote a sequential order of execution, but rather are used for convenience of description.

As shown in fig. 1 to 5, the present invention provides a crankshaft assembly suitable for a piston type two-stroke aircraft engine, which includes a crankshaft body, an oil pump driving cam 3, a main bearing 4 and an auxiliary bearing 2, wherein the main bearing 4 and the auxiliary bearing 2 are self-lubricating deep groove ball bearings, the crankshaft body is used for connecting a propeller and a magneto, the crankshaft body includes a crankshaft front crank 1, a crankshaft rear crank 10 and a crankshaft connecting crank arm 7 connected with the crankshaft front crank 1 and the crankshaft rear crank 10, the crankshaft front crank 1 is sleeved with the auxiliary bearing 2 and the main bearing 4, and the crankshaft rear crank 10 is sleeved with another main bearing 4.

Specifically, the main bearing 4 and the auxiliary bearing 2 both adopt self-lubricating deep groove ball bearings, the main bearing 4 and the auxiliary bearing 2 are lubricated without consuming mixed oil of a two-stroke engine, so that the oil consumption of the engine can be reduced, meanwhile, the self-lubricating bearing is sealed, the influence of the outside is small, and the reliability of the bearing is guaranteed. As shown in fig. 1, two main bearings 4 are provided, the two main bearings 4 are coaxially provided, the two main bearings 4 are used for supporting the crankshaft body, the two main bearings 4 are respectively sleeved on the crankshaft front crank 1 and the crankshaft rear crank 10, and the crankshaft front crank 1 and the crankshaft rear crank 10 are coaxially provided. The bent axle body is assembled bent axle, and what adopt simultaneously for lightweight etc. is not the structure of full support, and the bent axle body has two connecting rod necks and two main journals, and crank 1 and bent axle connection crank arm 7 link together through the interference pressure equipment before the bent axle, and crank 10 is also in the same place through the interference pressure equipment behind bent axle connection crank arm 7 and the bent axle, and for the main transmission part of bent axle, the pressure equipment interference is greater than 0.08mm, will control the axiality of two main journals simultaneously.

As shown in fig. 1, two main bearings 4 (deep groove ball bearings) and an auxiliary bearing 2 (deep groove ball bearings) are integrated on the crankshaft assembly, the main bearing 4 arranged on the crankshaft front crank 1 is in transition fit with the crankshaft front crank 1, the main bearing 4 arranged on the crankshaft rear crank 10 is in transition fit with the crankshaft rear crank 10, and the auxiliary bearing 2 is in transition fit with the crankshaft front crank 1, so that the reliability of the bearing is not affected, and meanwhile, the assembly of the bearing installation is considered; two connecting rod bearings 6 (needle roller bearings) are integrated on a connecting rod neck of the crankshaft assembly, the engine runs at a high speed, the needle roller bearings adopt a structure with a retainer, and the needle rollers are matched to bear pressure and are mutually independent, so that the service life of the bearing is prevented from being influenced by mutual friction among the needle rollers.

As shown in fig. 1, 2 and 4, the crankshaft front crank 1 includes a front shaft body 106, a front crank arm 107 connected with the front shaft body 106, and a front connecting rod neck 108 connected with the front crank arm 107 and connected with the crankshaft connecting crank arm 7, wherein a connecting rod bearing 6 is sleeved on the front connecting rod neck 108, the connecting rod bearing 6 is located between the crankshaft connecting crank arm 7 and the front crank arm 107, and the connecting rod bearing 6 is a needle bearing. The front shaft body 106 is configured to mount a propeller, the front shaft body 106 has a certain length, one end of the front shaft body 106 in a length direction is fixedly connected with the front crank arm 107, and one end of the front shaft body 106 in the length direction is used to mount the propeller. The front connecting rod neck 108 is a cylinder, the axis of the front connecting rod neck 108 is parallel to the axis of the front shaft body 106, one end of the front connecting rod neck 108 in the length direction is fixedly connected with the front crank arm 107, the other end of the front connecting rod neck 108 in the length direction is fixedly connected with the crank shaft to connect the crank arm 7, the front connecting rod neck 108 is in interference fit with the crank shaft to connect the crank arm 7, the front connecting rod neck 108 is connected with the crank shaft to connect the crank arm 7 through press fitting, the crank shaft is connected with the crank arm 7 to have a mounting hole for inserting the end of the front connecting rod neck 108, and the mounting hole is a.

As shown in fig. 1 and 2, in order to ensure the reliability of the connecting rod bearing 6 (needle bearing), the connecting rod bearing 6 is a needle bearing with a cage. The small end of the engine connecting rod is sleeved on the connecting rod bearing 6, the front connecting rod neck 108 is provided with a front oil storage groove 104 for containing a lubricating medium, and a front lubricating oil hole 103 for leading the lubricating medium in the front oil storage groove 104 to the connecting rod bearing 6, and the lubricating medium is grease. The front oil storage groove 104 extends along the axial direction of the front connecting rod neck 108, the front oil storage groove 104 is a round hole formed in the center of the front connecting rod neck 108, the front oil storage groove 104 is formed by extending from the end face of one end of the front connecting rod neck 108 connected with the crankshaft connecting crank arm 7 to the other end of the front connecting rod neck 108 along the axial direction of the front connecting rod neck 108, the front lubricating oil hole 103 is a round hole, the axis of the front lubricating oil hole 103 is perpendicular to the axis of the front oil storage groove 104, the front lubricating oil hole 103 forms an opening for flowing out a lubricating medium on the outer circular surface of the front connecting rod neck 108, the outer circular surface of the front connecting rod neck 108 is in contact with the inner circular surface of the connecting rod bearing 6, and then the lubricating medium enters between the connecting rod bearing 6 and the outer circular surface of the front connecting rod neck 108.

As shown in fig. 1 and 2, it is preferable that a vertical distance between the front lubrication hole 103 and an axis of the front shaft body 106 is greater than a vertical distance between an axis of the front neck 108 and an axis of the front shaft body 106, and the front lubrication hole 103 is located at an upper half portion of the front neck 108 to ensure that the lubrication medium in the front oil reservoir 104 can be thrown outward by a centrifugal force so that the lubrication medium can enter the connecting rod bearing 6 through the front lubrication hole 103.

As shown in fig. 1 and 2, for convenience of maintenance, the front crank arm 107 is provided with a front plug hole 102 communicating with the front oil reservoir 104, a front plug 5 is provided in the front plug hole 102, the front plug 5 is inserted into the front plug hole 102, the front plug 5 is in threaded connection with the front crank arm 107, the front plug hole 102 forms an opening on an outer circumferential surface of the front crank arm 107, the front plug hole 102 is a circular hole formed by extending the outer circumferential surface of the front crank arm 107 toward an inner wall of the front crank arm 107 along a length direction of the front crank arm 107, and the front plug hole 102 communicates with one end of the front oil reservoir 104. Before the crankshaft press-fitting assembly, the front screw block hole 102 can be used for guiding the lubricating medium into the front oil storage groove 104 when the lubricating medium is injected, and then the front screw block 5 is embedded into the front screw block hole 102 to block the front screw block hole 102, so that the first injection of the lubricating medium is completed. When the engine is running, the grease in the front oil reservoir 104 gradually flows out of the oil holes by centrifugal force, high temperature, or the like, and reaches the surface of the needle bearing, thereby lubricating the needle bearing on the front pin 108. When the engine is maintained, the front plug 5 is removed from the front plug hole 102 of the front crank 1 of the crankshaft by a tool, and grease is injected into the front oil reservoir 104 through the front plug hole 102 for maintenance, so that the lubrication of the needle bearing is mainly lubricated by the grease stored in the front oil reservoir 104. Due to the change of the lubricating mode, the quantity of the mixed oil consumed by the needle bearing is greatly reduced, so that the effect of reducing oil consumption can be achieved, the lubricating condition of the needle bearing is improved, and the reliability of the engine can be improved. The front plug 9 serves to close an opening of the front oil reservoir 104 formed in the end face of the front rod neck 108.

As shown in fig. 1 and 2, a weight-removing hole is formed at the center of the front shaft body 106, the weight-removing hole is a circular hole formed at the inner center of the front shaft body 106, and the minimum wall thickness of the front shaft body 106 is 3 mm. Meanwhile, the part of the balance weight close to the rotation center of the crankshaft is subjected to de-weighting processing, such as a de-weighting hole 105 arranged on the balance weight of the front crank 1 of the crankshaft in fig. 2, so as to ensure the lightest weight of the crankshaft. And the arrangement of the front oil reservoir 104 in the front pin 108 also provides a weight reduction effect. The front shaft body 106 has a front contact surface 101 which is located in the center hole of the propeller and contacts the propeller, and the front contact surface 101 is a conical surface. The power output of the crankshaft is connected by the conical surfaces, and the conical surface connection has the advantages that the coaxiality of the propeller and the crankshaft is good, namely, the centering performance is very good, meanwhile, the conical surface connection has large transmission torque, the structure is simple, the manufacture is convenient, and the reliability of the whole structure can be improved by the conical surface connection.

As shown in fig. 1, 3 and 4, the crankshaft rear crank 10 includes a rear shaft body 1007, a rear crank arm 1008 connected to the rear shaft body 1007, and a rear connecting neck 1009 connected to the rear crank arm 1008 and connected to the crankshaft connecting crank arm 7, wherein a connecting rod bearing 6 is sleeved on the rear connecting neck 1009, the connecting rod bearing 6 is located between the crankshaft connecting crank arm 7 and the rear crank arm 1008, and the connecting rod bearing 6 is a needle bearing. The rear shaft body 1007 is configured to be coupled to a magneto, the rear shaft body 1007 has a length, one end of the rear shaft body 1007 in a length direction is fixedly coupled to the rear crank arm 1008, and one end of the rear shaft body 1007 in the length direction is configured to be coupled to the magneto. The rear connecting rod neck 1009 is a cylinder, the axis of the rear connecting rod neck 1009 is parallel to the axis of the rear shaft body 1007, the front shaft body 106 and the rear shaft body 1007 are coaxially arranged, the axes of the front shaft body 106 and the rear shaft body 1007 are also the axes of the crankshaft body, an included angle between the axis of the rear connecting rod neck 1009 and the axis of the front connecting rod neck 108 is 180 degrees, one end of the rear connecting rod neck 1009 in the length direction is fixedly connected with the rear crank arm 1008, the other end of the rear connecting rod neck 1009 in the length direction is fixedly connected with the crankshaft connecting crank arm 7, the rear connecting rod neck 1009 is in interference fit with the crankshaft connecting crank arm 7, the rear connecting rod neck 1009 is connected with the crankshaft connecting crank arm 7 through press fitting, the crankshaft connecting crank arm 7 is provided with a mounting hole for inserting the end of the rear connecting rod.

As shown in fig. 1 and 3, in order to ensure the reliability of the connecting rod bearing 6 (needle bearing), the connecting rod bearing 6 is a needle bearing with a cage. The small end of the engine connecting rod is sleeved on the connecting rod bearing 6, the rear connecting rod neck 1009 has a rear oil storage groove for containing a lubricating medium and a rear lubricating oil hole 1003 for guiding the lubricating medium in the rear oil storage groove to the connecting rod bearing 6, and the lubricating medium is grease. The rear oil storage groove extends along the axial direction of the rear connecting rod neck 1009, the rear oil storage groove is a round hole formed in the center of the rear connecting rod neck 1009, the rear oil storage groove is formed by extending the round hole from the end face of the end of the rear connecting rod neck 1009, which is connected with the crankshaft connecting crank arm 7, to the other end of the rear connecting rod neck 1009 in the axial direction of the rear connecting rod neck 1009, the rear lubricating oil hole 1003 is a round hole, the axis of the rear lubricating oil hole 1003 is perpendicular to the axis of the rear oil storage groove, the rear lubricating oil hole 1003 forms an opening for allowing a lubricating medium to flow out on the outer circular surface of the rear connecting rod neck 1009, the outer circular surface of the rear connecting rod neck 1009 is in contact with the inner circular surface of the connecting rod bearing 6 sleeved on the rear connecting rod neck 1009, and then the lubricating medium enters between the outer circular surfaces.

As shown in fig. 1 and 3, preferably, a vertical distance between the rear lubrication oil hole 1003 and an axis of the rear shaft body 1007 is greater than a vertical distance between an axis of the rear connecting rod neck 1009 and an axis of the rear shaft body 1007, and the rear lubrication oil hole 1003 is located at a lower half portion of the rear connecting rod neck 1009, so that a lubrication medium in the rear oil storage tank can be thrown outwards under the action of centrifugal force, and the lubrication medium can enter the connecting rod bearing 6 through the rear lubrication oil hole 1003.

As shown in fig. 1 and 3, for convenience of maintenance, the rear crank arm 1008 is provided with a rear plug hole 1002 communicated with the rear oil storage tank, the rear plug hole 1002 is provided with a rear plug, the rear plug is inserted into the rear plug hole 1002 and is in threaded connection with the rear crank arm 1008, the rear plug hole 1002 forms an opening on the outer circumferential surface of the rear crank arm 1008, the rear plug hole 1002 is a circular hole formed by extending the outer circumferential surface of the rear crank arm 1008 along the length direction of the rear crank arm 1008 toward the inner wall of the rear crank arm 1008, the length direction of the front crank arm 107 is parallel to the length direction of the rear crank arm 1008, and the rear plug hole 1002 is communicated with one end of the rear oil storage tank. Before the crankshaft press-fitting assembly, the rear plug hole 1002 can be used for guiding a lubricating medium into the rear oil storage groove when the lubricating medium is injected, and then the rear plug is embedded into the rear plug hole 1002 to plug the rear plug hole 1002, so that the lubricating medium is injected for the first time. When the engine is running, the grease in the rear oil reservoir gradually flows out of the oil holes by centrifugal force, high temperature, or the like, and reaches the surface of the needle bearing, thereby lubricating the needle bearing on the rear connecting rod neck 1009. When the engine is maintained, the rear plug is removed from the rear plug hole 1002 of the crankshaft rear crank 10 by a tool, and then grease is injected into the rear oil reservoir through the rear plug hole 1002 for maintenance, so that the lubrication of the needle roller bearing is mainly lubricated by the grease stored in the rear oil reservoir. Due to the change of the lubricating mode, the quantity of the mixed oil consumed by the needle bearing is greatly reduced, so that the effect of reducing oil consumption can be achieved, the lubricating condition of the needle bearing is improved, and the reliability of the engine can be improved. The rear plug is used to close an opening formed in the end face of the rear connecting rod neck 1009 by the rear oil reservoir.

As shown in fig. 1 and 3, a weight-removing hole is formed at the center of the rear shaft body 1007, and the weight-removing hole is a circular hole formed at the inner center of the rear shaft body 1007. Meanwhile, the part of the balance weight close to the rotation center of the crankshaft is processed for removing the weight, such as a weight removing hole 1004 arranged on the balance weight of the crankshaft rear crank 10 in fig. 3, so as to ensure the lightest weight of the crankshaft. And the arrangement of the rear oil storage groove on the rear connecting rod neck 1009 also has the weight reduction effect.

As shown in FIG. 3, the crankshaft rear crank 10 is provided with a signal tooth positioning surface and two signal tooth threaded holes, which makes a good contribution to the integration of the whole machine.

As shown in fig. 1, an oil pump driving cam 3 is provided on a front crank 1 of the crankshaft, and the oil pump driving cam 3 is located between a main bearing 4 and an auxiliary bearing 2. The oil pump driving cam 3, the auxiliary bearing 2 and the main bearing 4 are sleeved on the front shaft body 106, the oil pump driving cam 3 is an eccentric bearing, and the oil pump driving cam 3 is used for driving a fuel pump. The oil pump driving cam 3 is designed into an eccentric bearing structure, the weight of the cam is greatly reduced, the problem of abrasion of the surface of the cam is also greatly reduced, and the reliability is higher.

Referring to fig. 1 and 4, the crank arm 7 is designed to be a weight-reducing structure similar to an 8 shape, so that the design of light weight can be realized to the maximum extent, two mounting holes on the crank arm 7 are shaft holes matched with the crank of the crankshaft, and the diameter, parallelism, center distance and the like of the two shaft holes directly influence the final assembly quality of the crankshaft assembly.

The crankshaft assembly with the structure has the advantages of light weight, low oil consumption, integration, simple structure and high reliability.

The design for light weight is characterized in that enough weight removing holes are designed at the connecting rod necks of the front crank 1 and the rear crank 10 of the crankshaft, enough weight removing holes are designed at the main journals of the front crank 1 and the rear crank 10 of the crankshaft, the balance block of the front crank 1 of the crankshaft is designed with the weight removing holes, and the balance block of the rear crank 10 of the crankshaft is designed with the weight removing holes.

The crank shaft connecting crank arm 7 is in an 8-shaped weight reduction structure.

The design for low oil consumption is mainly characterized in that a crankshaft main shaft bearing adopts a self-lubricating bearing (deep groove ball bearing), a needle bearing with a retainer is adopted as a needle bearing of a connecting rod journal, lubricating grease is added into weight removing holes in the connecting rod journal of a crankshaft front crank 1 and a crankshaft rear crank 10, and the stored lubricating grease is thrown to the surface of the bearing through the rotation of a machine to lubricate the needle bearing. Therefore, the bearing of the engine is basically free from consuming the mixed oil, and finally, the function of reducing oil consumption is achieved.

The integrated design is mainly characterized in that an eccentric cam (an eccentric bearing) for driving a fuel pump is integrated on a crankshaft, and a design for mounting a signal wheel is integrated on the crankshaft.

The high-reliability design is mainly characterized in that an auxiliary journal is additionally arranged on the output end of the crankshaft and the end of an eccentric cam (an eccentric bearing) for driving the fuel pump, the strength of the crankshaft can be effectively improved, the reliability is improved, lubricating grease filling plugs are arranged on the arc surfaces of crank arms of the crankshaft front crank 1 and the crankshaft rear crank 10, lubricating grease can be filled into a lubricating grease storage tank from a plug hole when the engine is maintained, the service life of the needle bearing is prolonged, and meanwhile, the maintenance is convenient.

The high-reliability design is also shown in connection of the front end and the rear end of the crankshaft, the conical surface design can ensure more accurate centering of the front end rotating piece and the rear end rotating piece, namely, the phenomenon that the crankshaft caused by eccentricity bears extra centrifugal force is reduced, meanwhile, the conical surface connection can provide enough torque, the safety of power output of a small engine and the convenience of end connection of a magnetic motor are ensured, and further the reliability of the engine is improved.

The invention is described above with reference to the accompanying drawings. It is to be understood that the specific implementations of the invention are not limited in this respect. Various insubstantial improvements are made by adopting the method conception and the technical scheme of the invention; the present invention is not limited to the above embodiments, and can be modified in various ways.