CN207420716U - The crankshaft group and engine of engine - Google Patents

Abstract

The crankshaft group and engine of a kind of engine, wherein, the crankshaft group of engine includes：Bent axle, the output terminal of bent axle are arranged with belt pulley, and belt pulley includes：The belt wheel body and the first axle sleeve being wholely set；The output terminal of bent axle is provided with the first keyway, and the first positioning key is provided in the first keyway, and the first axle of belt pulley, which is put on, is provided with the first matching hole, and the first matching hole is used to coordinate with the first positioning key；Bolt hole is additionally provided on bent axle, belt pulley and bent axle is fastened by bolt.First keyway is set by the output terminal in bent axle, first positioning key is set in the first keyway, the first matching hole is set on the first axle set of belt pulley, it is used to coordinate with the first positioning key by the first matching hole, belt pulley is mounted on bent axle, and is further fastenedly connected belt pulley and bent axle by bolt, it ensure that the installation reliability of belt pulley, the assembling of bent axle and belt pulley is not only convenient for, after belt pulley failure, is also convenient for the dismounting of belt pulley.

Description

The crankshaft group and engine of engine

Technical field

The utility model is related to automobile engine technology more particularly to the crankshaft groups and engine of a kind of engine.

Background technology

Bent axle is the main rotating mechanism in engine, is mainly used for the transformation that pumps of piston in engine For the circular motion of itself, other power set connected to it to be driven to move, and then vehicle operation is driven.The output of bent axle End is usually provided with belt pulley, with the biography by the way that the rotary power of bent axle to be passed to vehicle chassis with the belt that belt pulley coordinates Motivation structure.

At present, the assembly method of belt pulley and bent axle is typically using interference fit, specifically on dedicated heating equipment Bent axle and belt pulley are heated, and belt pulley is sleeved on bent axle using instrument.However, in above-mentioned assembling process, it is right The heating temperature of bent axle and belt pulley is difficult to control, and increases assembly difficulty；And it after belt pulley failure, dismantles also very not Just.

Utility model content

For drawbacks described above of the prior art, the utility model provides a kind of crankshaft group and engine of engine, The assembling of bent axle and belt pulley can be overcome difficult, and after belt pulley failure, dismantle the problem of also very inconvenient.

The first aspect of the utility model is to provide a kind of crankshaft group of engine, including：Bent axle, the bent axle Output terminal is arranged with belt pulley, and the belt pulley includes：The belt wheel body and the first axle sleeve being wholely set；The bent axle it is defeated Outlet is provided with the first keyway, and the first positioning key is provided in first keyway, and the first axle of the belt pulley puts on setting There is the first matching hole, first matching hole is used to coordinate with first positioning key；Bolt hole is additionally provided on the bent axle, So that bolt is through the belt pulley and is fixed in the bolt hole.

Further, the output terminal of the bent axle is additionally provided with lubricating oil pump drive sprocket, and second is provided on the bent axle Keyway is provided with the second positioning key in second keyway, is provided with the second matching hole on lubricating oil pump drive sprocket, and described second Matching hole is used to coordinate with second positioning key.

Further, first positioning key and/or second positioning key are woodruff key.

Further, second matching hole is through hole.

Further, the lubricating oil pump drive sprocket includes：The first sprocket body being wholely set and the second axle sleeve.

Further, the shaft shoulder is additionally provided on the bent axle, head end end face and the shaft shoulder of second axle sleeve offset It leans on.

Further, the output terminal of the bent axle is additionally provided with timing drive sprocket, and the timing drive sprocket is folded in Between the lubricating oil pump drive sprocket and the belt pulley.

Further, the timing drive sprocket includes：The second sprocket body being wholely set and the 3rd axle sleeve.

Further, the 3rd matching hole is additionally provided on the timing drive sprocket, the 3rd matching hole is used for and institute State the cooperation of the second positioning key.

The other side of the utility model is to provide a kind of engine, including：Cylinder, piston, piston rod and song Shaft assembly, for the piston for being moved back and forth in the cylinder, the piston passes through the piston rod and the crankshaft group In bent axle connection, drive the bent axle rotary motion to pass through the reciprocating motion of the piston；Wherein, the crankshaft group is The crankshaft group of foregoing any one of them engine.

The crankshaft group and engine of engine provided by the utility model set the by the output terminal in the bent axle One keyway sets the first positioning key in first keyway, and the first matching hole is set on the first axle set of the belt pulley, It is used to coordinate with first positioning key by first matching hole, the belt pulley is mounted on the bent axle, and Further belt pulley and bent axle are fastenedly connected by bolt, ensure that the installation reliability of belt pulley, be not only convenient for bent axle with The assembling of belt pulley after belt pulley failure, is also convenient for the dismounting of belt pulley.

Description of the drawings

Fig. 1 is the diagrammatic cross-section of the crankshaft group of the utility model embodiment engine；

Fig. 2 is the structure diagram of the crankshaft group middle belt pulley of the utility model embodiment engine；

Fig. 3 be the utility model embodiment engine crankshaft group in bent axle structure diagram；

Fig. 4 be the utility model embodiment engine crankshaft group in lubricating oil pump drive sprocket structure diagram；

Fig. 5 be the utility model embodiment engine crankshaft group in timing drive sprocket structure diagram；

Fig. 6 is the assembling schematic diagram of the crankshaft group of the utility model embodiment engine.

Wherein,

100- bent axles；The first positioning keys of 110-；

The second positioning keys of 120-；The 130- shaft shoulders；

140- bolts hole；150- bolts；

200- belt pulleys；210- belt wheel bodies；

The first axle sleeves of 220-；The first matching holes of 200a-；

300- lubricating oil pump drive sprockets；310- the first drive sprocket bodies；

The second axle sleeves of 320-；The second matching holes of 300a-；

400- timing drive sprockets；410- the second drive sprocket bodies；

The 3rd axle sleeves of 420-；The 3rd matching holes of 400a-.

Specific embodiment

It is new below in conjunction with this practicality to make the purpose, technical scheme and advantage of the utility model embodiment clearer Attached drawing in type embodiment, the technical scheme in the utility model embodiment is clearly and completely described, it is clear that is retouched The embodiment stated is the utility model part of the embodiment, instead of all the embodiments.

Based on the embodiment in the utility model, those of ordinary skill in the art are without making creative work All other embodiments obtained shall fall within the protection scope of the present invention.In the case where there is no conflict, following implementation Feature in example and embodiment can be mutually combined.

Wherein, the term of " head ", " end " etc. is for describing the relative position relation of each structure in the accompanying drawings, is only Convenient for understanding rather than to limit the enforceable scope of the utility model for narration, relativeness is altered or modified, in nothing Under essence change technology contents, when being also considered as the enforceable scope of the utility model.

It should be noted that in the description of the utility model, term " first ", " second " are only used for facilitating description different Component, and it is not intended that instruction or implying ordinal relation, relative importance or implicit indicating indicated technical characteristic Quantity." first " is defined as a result, at least one this feature can be expressed or be implicitly included to the feature of " second ".

Automobile is the power set driving by means of itself, and the non-track with the wheel of 4 or 4 or more is without stringing Vehicle is mainly used for carrying people and/or cargo, traction carrying people and/or cargo.Automobile is divided into common carrier according to purposes And special-purpose vehicle, wherein, common carrier can be divided into car, car, lorry again.

Automobile overall structure includes：Engine, chassis, vehicle body and electric appliance and electronic equipment four are most of；Wherein, start Machine is the fuel combustion that conveying is made to come in and starts from inner component, is the power set of automobile；Chassis receives engine Power, makes motor racing and the component of normally travel by the manipulation of driver, is the matrix of automobile, is equipped with power train thereon System, driving system, steering and braking system；Vehicle body is carried and is mounted on chassis, be driver workplace and The component of passenger loading and cargo.

The forepart of vehicle body is usually provided with enging cabin, and engine is arranged in enging cabin.At present, most of automobiles Engine is four stroke reciprocating piston internal combustion engines, is mainly included：Body group, toggle, valve actuating mechanism, intake and exhaust system System, fuel system, cooling system, lubricating system, starting system and noxious emission control device.

Wherein, body group is the stent of engine, is toggle, valve actuating mechanism and each system of engine main zero The assembling matrix of component.Body group mainly includes：Body, cylinder head, valve mechanism cover, Cylinder head gasket, main beating cap and oily bottom Shell.

Body is that big part is made in engine, is the continuous casting body of cylinder block and crankcase, is primarily subjected to tensile, compressive, bending, turns round Meet etc. various forms of machineries, at the same also because the very big heat of being born when contacting directly with high-temperature fuel gas meets, therefore, body Enough strength and stiffness are needed to have, and it is wear-resisting, corrosion-resistant, and carry out appropriate cooling.Cylinder head is complicated case Shape part is primarily subjected to gas force and fastens the mechanical load caused by cylinder head bolt, while due also to connect with high-temperature fuel gas It touches and bears very high thermic load；Cylinder head is additionally operable at the top of closed cylinder, and forms burning calmly and together with cylinder wall with piston Room.Oil sump is mainly used for storing machine oil and closes body or crankcase.In addition, cylinder head and the in vivo water jacket of machine and oil duct And oil sump be divided into be not cooling system and lubricating system component.

Toggle is the main movement mechanism of engine, is mainly used for the reciprocating motion of piston being changed into bent axle Rotary motion, while be changed into the torque and the wheel for driving automobile that bent axle externally exports with the power on piston by acting on It rotates.Toggle is mainly made of piston group, connection rod set and crankshaft-flywheel group.

Piston in piston group is mainly used for into the pressure into burning gases, and this pressure is passed to company by piston pin Bar is to promote bent axle to rotate；The top of piston also collectively constitutes combustion chamber with cylinder head, cylinder wall.

The power that connection rod set is mainly used for bearing in piston passes to bent axle, and the reciprocating motion of piston is changed into bent axle Rotary motion.In connection rod set, microcephaly and the piston pin connection Ei of connecting rod, logical piston move back and forth together；The major part of connecting rod and song Handle pin connection rotates together with bent axle.

Crankshaft-flywheel group includes：Bent axle, bent axle are mainly used for the gas force that piston, connecting rod transmit to be changed into torque, use To drive the valve actuating mechanism of the transmission system of automobile and engine and other auxiliary devices；Bent axle is in its periodically variable body It works under the collective effect of power, inertia force and its torque, bears to bend and reverse the load of alternation, therefore, bent axle should have Enough counter-bending, anti-torsion fatigue strength and rigidity.

Bent axle is substantially made of several and unit crank throw, two crank-pin, two crank arms in left and right and left and right masters Axle journal forms a unit crank throw.Only there are one unit crank throws for the bent axle of horizontal bar engine；The unit of multi-cylinder in-line formula engine Crank throw number is identical with number of cylinders；The unit crank throw number of V-type engine bent axle is equal to the half of number of cylinders.

Trunnion and crank-pin are typically all solid；Certainly, part forged steel crankshaft crank-pin is made hollow, to subtract The quality of small crank pin and its rotating inertia force of generation；Part cast iron crank trunnion and crank-pin are cast it is hollow, And spron is cast on crank arm, to reduce stress concentration and increase fatigue strength.

Crank arm group will be used to connect trunnion and crank-pin, be usually ellipse, so that crank is with higher Bending stiffness and torsion stiffness.The center of gravity of crank arm should be set close proximity to the revolution center of gravity of bent axle.

In addition, bent axle also sets left and right crankshaft balance weight, it is used to come balance rotating inertia and its torque.Crankshaft balance weight is in more Sector, so that its center of gravity is put down away from crank up center of gravity so as to obtain larger rotating inertia force bent axle under smaller quality Weight can be wholely set with crank arm, can also be bolted connection.

When engine works, under the torque of mechanical periodicity, each unit crank throw generating period is opposite to be turned round bent axle Turn, which is known as torsional oscillation.When the change frequency of motor torque and the natural frequency of vibration of crankshaft torsion are identical or during into integral multiple, It will resonate.Torsional amplitudes increase during resonance, and cause transmission mechanism abrasion aggravation, and engine power declines or even makes Crankshaft breakdown.

To solve the problems, such as this, crankshaft-flywheel group further includes：Torsional vibration damper, torsional vibration damper can be rubber torsion damping Device, silicone oil torsion vibration damper and silicone oil-rubber torsional vibration damper.By taking rubber torsional vibration damper as an example：The housing of torsional vibration damper It is connected with bent axle, when engine works, housing vibrates together with bent axle, since inertia mass lags behind housing, thus two Relative motion is generated between person so that rubber layer is rubbed back and forth, and vibrational energy is absorbed by the interior friction footprint in rubber, so as to disappear Subtract the twisting vibration of bent axle.

For four-stroke engine, once, only working stroke does work for every four piston strokes acting, and be vented, Three strokes of air inlet and compression will consume work(, and therefore, the torque that bent axle externally exports is in cyclically-varying, the rotating speed of bent axle It is unstable.

In order to improve the above situation, crankshaft-flywheel group further includes：Flywheel, flywheel pass through positioning pin or the bolt of Unequal distance It is fastened on the rear end of bent axle.Flywheel is the very big disk-shaped part of rotary inertia；Engine is transferred to bent axle in working stroke Energy in addition to external output, also has portion of energy to be absorbed by flywheel, will not be raised much so as to the rotating speed of bent axle；Exhaust, into In three strokes of gas and compression, the energy that flywheel is absorbed storage releases and compensates the work(that is consumed of these three strokes, thus So that the rotating speed of bent axle will not reduce too much.

In addition, the output terminal of bent axle is usually provided with belt pulley, lubricating oil pump drive sprocket and timing sprocket, to realize driving The transmission system of automobile and the function of the valve actuating mechanism of engine and other auxiliary devices.Below to the output terminal and skin of bent axle The fit structure of belt wheel, lubricating oil pump drive sprocket and timing sprocket is described in detail.

Fig. 1 is the diagrammatic cross-section of the crankshaft group of the utility model embodiment engine；Fig. 2 is implemented for the utility model The structure diagram of the crankshaft group middle belt pulley of example engine；Fig. 3 is the crankshaft group of the utility model embodiment engine The structure diagram of middle bent axle.

Fig. 1-3 are refer to, the present embodiment provides a kind of 100 component of bent axle of engine, including：Bent axle 100, bent axle 100 Output terminal be arranged with belt pulley 200, belt pulley 200 includes：210 and first axle sleeve 220 of belt wheel body, belt wheel body 210 It is wholely set with the first axle sleeve 220；The output terminal of bent axle 100 is provided with the first keyway, and the first positioning is provided in the first keyway Key 110, is provided with the first matching hole 200a on the first axle sleeve 220 of belt pulley 200, the first matching hole 200a be used for it is first fixed Position key 110 coordinates；Bolt hole 140 is additionally provided on bent axle 100, so that bolt 150 is through belt pulley 200 and is fixed on bolt hole It is fastened in 140 namely by bolt 150 by belt pulley 200 and bent axle 100.

Bent axle 100 is typically to be formed by medium carbon steel or medium carbon alloy steel die forging；In order to improve the wearability of bent axle 100 and Endurance life, the part surface or all surfaces of bent axle 100 can also summarize nitrogen treatment through high-frequency quenching, and carry out essence Mill processing, to reach higher case hardness and surface roughness.

Belt pulley 200 includes 210 and first axle sleeve 220 of belt wheel body, 210 and first axle sleeve of belt wheel body, 220 one It sets, when being carried out maintenance to engine, when dismantling belt pulley 200, the first axle sleeve 220 can be dismantled simultaneously, avoided solely Erect the problem of the first axle sleeve 220 put is carried over breaking in dismounting；Also, 220 axially projecting belt wheel sheet of the first axle sleeve Body 210 is set, and so as to add the length of fit and contact area of belt pulley 200 and bent axle 100, and then improves belt pulley 200 installation reliability.In addition, on the head end end face of belt wheel body 210 namely towards on the end face of bent axle 100, can set There is cavity, rubber block or rubber pad with shock-absorbing function can be set in cavity.

The first keyway is offered at the suitable position of bent axle 100, is provided with the first positioning key 110 in the first keyway, first Positioning key 110 can be woodruff key, in order to the processing and manufacturing of the first positioning key 110 and the first keyway.On belt pulley 200 First matching hole 200a can be through hole or blind hole, can specifically be configured according to actual needs.Bolt 150 specifically can be with Using high-strength bolt；The end of bent axle 100 can be stepped, and correspondingly, belt pulley 200 is used for what is coordinated with bent axle 100 Centre bore is also stepped, and belt pulley 200 is set on bent axle 100, and after passing through 110 location and installation of the first positioning key, Further belt pulley 200 and bent axle 100 are fastenedly connected by bolt 150.Wherein, the first positioning key 110 plays positioning with being oriented to Effect.

100 component of bent axle of engine provided in this embodiment sets the first keyway by the output terminal in bent axle 100, First positioning key 110 in the first keyway is set, first matching hole 200a is set on the first axle sleeve 220 of belt pulley 200, is led to The first matching hole 200a is crossed for coordinating with the first positioning key 110, belt pulley 200 is mounted on bent axle 100, and passes through spiral shell Belt pulley 200 and bent axle 100 are further fastenedly connected by bolt 150, be ensure that the installation reliability of belt pulley 200, are not only convenient for The assembling of bent axle 100 and belt pulley 200 after the failure of belt pulley 200, is also convenient for the dismounting of belt pulley 200.

Since 100 long-time of bent axle is rotated, the contact surface with some components can be there are fretting wear, in order to subtract The small abrasion to bent axle 100 is, it is necessary to be lubricated bent axle 100 with the lubricating oil of viscosity properly, with certain cleannes.Specifically Ground improves engine oil pressure by lubricating oil pump and ensures certain oil mass, to force fuel feeding to each friction surface.

Fig. 4 be the utility model embodiment engine crankshaft group in lubricating oil pump drive sprocket structure diagram.

Fig. 4 is refer to, and with continued reference to Fig. 1 and Fig. 3, further, the output terminal of bent axle 100 is additionally provided with lubricating oil pump drive Movable sprocket 300, lubricating oil pump drive sprocket 300 are used to drive machine oil pump operation；The second keyway, the second key are provided on bent axle 100 The second positioning key 120 is provided in slot, the second matching hole 300a, the second matching hole are provided on lubricating oil pump drive sprocket 300 300a is used to coordinate with the second positioning key 120.

Specifically, lubricating oil pump drive sprocket 300 can include：The first sprocket body 310 being wholely set and the second axis Set 320.When dismantling lubricating oil pump drive sprocket 300, the second axle sleeve 320 can be dismantled simultaneously, avoid independently arranged second The problem of axle sleeve 320 is carried over breaking in dismounting；Also, 320 axially projecting first sprocket body 310 of the second axle sleeve is set It puts, so as to add the length of fit and contact area of lubricating oil pump drive sprocket 300 and bent axle 100, and then improves machine oil Pump the installation reliability of drive sprocket 300.

Within the engine, timing system is further typically provided with, be connected by timing system with bent axle 100 and is coordinated is certain Gearratio ensures engine charge, the accuracy of evacuation time.

Fig. 5 be the utility model embodiment engine crankshaft group in timing drive sprocket structure diagram.

Fig. 5 is refer to, and with continued reference to Fig. 1 and Fig. 3, further, the output terminal of bent axle 100 is additionally provided with timing driving Sprocket wheel 400, for coordinating with timing system；Timing drive sprocket 400 is folded in lubricating oil pump drive sprocket 300 and belt pulley 200 Between.

Specifically, timing drive sprocket 400 includes：The second sprocket body 410 being wholely set and the 3rd axle sleeve 420. When dismantling timing drive sprocket 400, the 3rd axle sleeve 420 can be dismantled simultaneously, independently arranged 3rd axle sleeve 420 is avoided to exist The problem of being carried over breaking during dismounting；Also, 420 axially projecting second sprocket body 410 of the 3rd axle sleeve is set, so as to increase The length of fit and contact area of timing drive sprocket 400 and bent axle 100, and then improve timing drive sprocket 400 Installation reliability.

Further, the shaft shoulder 130 is additionally provided on bent axle 100, head end end face and the shaft shoulder 130 of the second axle sleeve 320 offset It leans on.The head end end face of 3rd axle sleeve 420 and the distal end faces of the second axle sleeve 320 lean.The head end end face of first axle sleeve 220 with The distal end faces of 3rd axle sleeve 420 lean.Wherein, by the cooperation of the bolt hole 140 on bolt 150 and bent axle 100, by the One axle sleeve 220, the second axle sleeve 320 and the 3rd axle sleeve 420 compress, and the second axle sleeve 320 is made to lean with the shaft shoulder 130.

Key-groove is also provided on bent axle 100, the 3rd positioning key, timing drive sprocket are provided in key-groove The matching hole for coordinating with the 3rd positioning key is provided on 400, is matched somebody with somebody by the 3rd positioning key and key-groove, matching hole It closes, realizes the location and installation of timing drive sprocket 400.

It is preferred that be additionally provided with the 3rd matching hole 400a on timing drive sprocket 400, the 3rd matching hole 400a is used for and the Two positioning keys 120 coordinate namely timing drive sprocket 400, lubricating oil pump drive sprocket 300 pass through the second positioning key 120 and song 100 location and installation of axis so as to reduce the quantity for opening up keyway on bent axle 100, helps to ensure that the strong of bent axle 100 Degree.Wherein, the second positioning key 120 can be woodruff key, convenient for the processing and manufacturing of the second keyway；Second positioning key 120 plays positioning With guiding role.

It should be noted that：3rd matching hole 400a can be through hole or blind hole；Second matching hole 300a is through hole, with Convenient for the smooth assembling of lubricating oil pump drive sprocket 300 and timing drive sprocket 400.

Fig. 6 is the assembling schematic diagram of the crankshaft group of the utility model embodiment engine.

It refer to Fig. 6, and with continued reference to Fig. 1-5, in the present embodiment, the assembling process of 100 component of bent axle can be：It is first First, the second positioning key 120 and the second keyway are assembled；Lubricating oil pump drive sprocket 300 is set on bent axle 100, and causes the Two matching hole 300a and the second keyway coordinate；Timing drive sprocket 400 is set on bent axle 100 so that the 3rd matching hole 400a also coordinates with the second keyway, when the 3rd matching hole 400a is also fully mated with the second keyway, just by lubricating oil pump drive chain Second axle sleeve 320 of wheel 300 is pressed on the shaft shoulder 130 of bent axle 100；Then, the first positioning key 110 and the first keyway are filled Match somebody with somebody, belt pulley 200 is set on bent axle 100, and the first pilot hole and the first positioning key 110 are assembled in place；Finally, will Bolt 150 is screwed into the bolt hole 140 of bent axle 100, fastening is realized, by the first axle sleeve 220, the 3rd axle sleeve 420 and the second axle sleeve 320 compress with the shaft shoulder 130.

Wherein, in belt wheel body 210 towards the one side of the shaft shoulder 130,220 axially projecting (or stretching) band of the first axle sleeve Wheel body 210 is set；In the both sides of the first sprocket body 310, the second axle sleeve 320 protrudes the first sprocket body 310 vertically It sets；In the both sides of the second sprocket body 410, the 3rd axle sleeve 420 protrudes the second sprocket body 410 and sets vertically, to keep away Exempt to interfere between each component.

The present embodiment also provides a kind of engine, including：Cylinder, piston, piston rod and crankshaft group, piston are used for It moves back and forth in the cylinder, piston is connected by piston rod with the bent axle in crankshaft group, to pass through the reciprocating motion band of piston Dynamic crankshaft rotary motion；Wherein, crankshaft group is the crankshaft group of the engine in foregoing any embodiment.

Wherein, the structure of the crankshaft group of engine, function and previous embodiment are same or similar, no longer superfluous herein It states.

Engine provided in this embodiment sets the first keyway by the output terminal in bent axle, is set in the first keyway First positioning key sets the first matching hole on the first axle set of belt pulley, is used for and the first positioning key by the first matching hole Belt pulley is mounted on bent axle, and is further fastenedly connected belt pulley and bent axle by bolt by cooperation, ensure that belt The installation reliability of wheel is not only convenient for the assembling of bent axle and belt pulley, after belt pulley failure, is also convenient for the dismounting of belt pulley.

Finally it should be noted that：Various embodiments above is only to illustrate the technical solution of the utility model rather than it is limited System；Although the utility model is described in detail with reference to foregoing embodiments, those of ordinary skill in the art should Understand：It can still modify to the technical solution recorded in foregoing embodiments either to which part or whole Technical characteristic carries out equivalent substitution；And these modifications or replacement, the essence of appropriate technical solution is not made to depart from this practicality newly The scope of each embodiment technical solution of type.

Claims (10)

1. a kind of crankshaft group of engine, which is characterized in that including：Bent axle, the output terminal of the bent axle are arranged with belt pulley, The belt pulley includes：Belt wheel body and the first axle sleeve, the belt wheel body are wholely set with the first axle sleeve；The bent axle Output terminal is provided with the first keyway, and the first positioning key is provided in first keyway, and the first axle of the belt pulley, which is put on, to be set The first matching hole is equipped with, first matching hole is used to coordinate with first positioning key；Bolt is additionally provided on the bent axle Hole, so that bolt is through the belt pulley and is fixed in the bolt hole.

2. the crankshaft group of engine according to claim 1, which is characterized in that the output terminal of the bent axle is additionally provided with Lubricating oil pump drive sprocket is provided with the second keyway on the bent axle, the second positioning key, lubricating oil pump is provided in second keyway The second matching hole is provided on drive sprocket, second matching hole is used to coordinate with second positioning key.

3. the crankshaft group of engine according to claim 2, which is characterized in that first positioning key and/or described Second positioning key is woodruff key.

4. the crankshaft group of engine according to claim 2, which is characterized in that second matching hole is through hole.

5. the crankshaft group of engine according to claim 2, which is characterized in that the lubricating oil pump drive sprocket includes： The first sprocket body being wholely set and the second axle sleeve.

6. the crankshaft group of engine according to claim 5, which is characterized in that the shaft shoulder is additionally provided on the bent axle, The head end end face of second axle sleeve leans with the shaft shoulder.

7. the crankshaft group of engine according to claim 2, which is characterized in that the output terminal of the bent axle is additionally provided with Timing drive sprocket, the timing drive sprocket are folded between the lubricating oil pump drive sprocket and the belt pulley.

8. the crankshaft group of engine according to claim 7, which is characterized in that the timing drive sprocket includes：One The second sprocket body and the 3rd axle sleeve that body is set.

9. the crankshaft group of engine according to claim 7, which is characterized in that also set up on the timing drive sprocket There is the 3rd matching hole, the 3rd matching hole is used to coordinate with second positioning key.

10. a kind of engine, which is characterized in that including：Cylinder, piston, piston rod and crankshaft group, the piston are used for It is moved back and forth in the cylinder, the piston is connected by the piston rod with the bent axle in the crankshaft group, to pass through The reciprocating motion of the piston drives the bent axle rotary motion；Wherein, the crankshaft group is any one of claim 1-9 institutes The crankshaft group for the engine stated.