CN1818593A - Dynamic balance inspection of assembled crank link mechanism of single-cylinder engine - Google Patents

Abstract

A method for detecting dynamic balance of integrated crank link mechanism of single cylinder motorcycle includes calculating out vector corresponding main dip angle and unbalance rate of crankshaft then obtaining moment of inertia on crank itself, obtaining rotary moment of inertia for balance weight plate to be set on crank, designing size and erecting position as well as number of said plate, setting crank with designed balance weight plate on vertical balancing machine for being detected, marking unbalanced position and unbalanced amount out then drilling holes on crank according to marks.

Description

Dynamic balance inspection of assembled crank link mechanism of single-cylinder engine

Technical field

The invention belongs to the engine manufacturing technology field, specifically, relate to motorcycle engine built-up crank linkage assembly dynamic balance test method.

Background technology

At present, what the combination of the crank connecting link of single cylinder engine for motorcycle was generally adopted all is the excessive balance method, and its essence is exactly that the mass M ω that gets counterbalance weight makes its centrifugal intertia force surpass the gyrating mass M at crank pin place _RotThe centrifugal intertia force that produces.Be M ω * R ω＞M _Rot* r (see figure 2), thus a part of reciprocal inertia force is transferred to perpendicular to cylinder direction or other directions.This kind method is with low cost, is applicable to the single-barrel engine of little discharge capacity.The counterbalance weight mass distribution of bent axle is unreasonable, will cause the vibration that engine is bigger, when bent axle master inclination angle [theta] or unbalance factor γ can not meet design requirement, just needs the analytical method of mathematics, calculates the scheme of regulating the crankshaft counter balance quality.Because the drill centers operation can produce very big influence to the bent axle master inclination angle [theta] and the unbalance factor γ of crankshaft-link rod combination in the present bent axle processing technology, cause in the batch process, dynamic balance performance between each crank connecting link combination has very big difference, can not satisfy the use needs of engine, this situation is obvious especially on the big slightly 200ml single cylinder engine for motorcycle of discharge capacity.Current technology will be improved the dynamic balance performance of crank connecting link combination, needs elder generation with crank connecting link aggregate erection upper piston, piston pin and piston pin collar, detects its bent axle master's inclination angle [theta] and unbalance factor γ on the transient equilibrium comprehensive detector.If do not meet the demands, just need calculate separately with the mathematical analysis method, find the position of regulating the crankshaft counter balance quality, regulate the dynamic balance performance of bent axle with the mode of boring at this position.This method wastes time and energy, can only be when engine be manufactured experimently, can adopt in the time of perhaps need adjusting the main inclination angle [theta] of engine crankshaft and unbalance factor γ because of the change of car load, and can't in production in enormous quantities, use.

Summary of the invention

The purpose of this invention is to provide a kind of dynamic balance inspection of assembled crank link mechanism of single-cylinder engine, solve existing dynamic balance inspection of assembled crank link mechanism of single-cylinder engine and waste time and energy the problem that in production in enormous quantities, to use.

Dynamic balance inspection of assembled crank link mechanism of single-cylinder engine of the present invention, form by the following step:

(1) best bent axle master inclination angle of engine and the unbalance factor of determining according to experiment calculates the pairing vector of bent axle master inclination angle and unbalance factor:

$I=0.25M_{\mathrm{rec}}r\sqrt{1+{(1-2\mathrm{\γ})}^2-2(1-2\mathrm{\γ})\cos 2\mathrm{\θ}}$

tan(β-2θ)＝sin?2θ/(1-2γ-cos?2θ)

Wherein, I is the vector size, and β is a vector angle, M _RecBe the reciprocal gross mass of crank connecting link piston assembly, r is a crank length, and γ is a unbalance factor, and θ is main inclination angle;

(2) find the solution the rotation inertia moment of crank pin place gyrating mass generation and the rotation inertia moment of crank itself, computing formula is:

I ₁＝0.5×Mrot×r，β ₁＝0°

${\stackrel{\→}{I}}_2=\stackrel{\→}{I}-{\stackrel{\→}{I}}_1$

Wherein, I ₁Be the size of crank pin place gyrating mass generation rotation inertia moment, β ₁Be the angle of crank pin place gyrating mass generation rotation inertia moment, Mrot is the gyrating mass at crank pin place, and r is a crank length,

Rotation inertia moment for crank itself;

(3), obtain on crank, to install the rotator inertia square of balancing disk, and design quantity, size and the installation site of required balancing disk when detecting according to the rotation inertia moment of crank itself;

(4) crank that will assemble balancing disk places and does the transient equilibrium check on the vertical dynamic balancing machine, checks out non-equilibrium site and amount of unbalance, marks;

(5) hole according to being marked on the crank.

By being installed, balancing disk carries out the transient equilibrium detection among the present invention on the crank behind the correct grinding, when the crank behind the installation balancing disk is done the transient equilibrium check on vertical dynamic balancing machine, can be checked through the accurate position of unbalance mass,, this unbalance mass, is eliminated in boring on crank then, make crank reach the revolution balance, left and right sides crank after the method is assembled into the transient equilibrium effect that crank connecting link combination back just can reach expection, reach the bent axle master inclination angle and the unbalance factor of designing requirement, and the dynamic balance performance high conformity of crank connecting link combination.The balancing disk quantity of need installing, size and location can be calculated by formula as required and derive, and to the left and right sides crank of same specification, after the balancing disk design is determined and made, just can reuse on the transient equilibrium detection operation behind the crank correct grinding in batch process.Owing to needn't as traditional dynamic balance test method, on last crank connecting link combination finished product, piston, piston ring, piston pin and piston pin collar be installed when detecting, do not need with independent certain position boring of calculating of mathematical analysis method at crank yet, workpiece behind the installation balancing disk is checked convenient, fast on the vertical dynamic balancing machine of standard, and just can detect non-equilibrium site and amount of unbalance several seconds.

Remarkable result of the present invention is: it is time saving and energy saving to operate, convenient and swift, and the transient equilibrium of crank connecting link combination workpiece detects in especially being fit to produce in enormous quantities.

Description of drawings

Fig. 1 is the process flow diagram of the inventive method;

Fig. 2 is the synoptic diagram of excessive balance method;

Fig. 3 is the distribution plan that bent axle is made a concerted effort;

Force diagram when Fig. 4 is α for crank angle;

Force diagram when Fig. 5 is α+90 ° for crank angle;

Fig. 6 is a vector And

Presentation graphs;

Fig. 7 is that big balancing disk 1, little balancing disk 2 and mounting screw 3 are installed in the synoptic diagram on the crank (double dot dash line is represented).

Embodiment

Below in conjunction with drawings and Examples the present invention is described in further detail.

With the LF163FML-2 single cylinder engine for motorcycle is example, shows that according to a large amount of experiments the car load vibrating effect is best when the bent axle master inclination angle [theta]=80 °, unbalance factor γ=21%.This engine crank radius r=31.1mm; Piston, piston ring, piston pin, piston pin collar gross mass Mp=195g; Connecting rod quality M _L=200g, the connecting rod barycenter is to small end of connecting rod centre distance L _A=72.75mm; The connecting rod barycenter is to the distance L at big end center _B=32.75mm; Connecting rod concentric reducer hole centre distance L=L _A+ L _B=105.5mm; The crank pin mass M _Q=265g; Big end needle bearing M _Z=35g.As shown in Figure 1, follow these steps to this single cylinder engine for motorcycle built-up crank linkage assembly transient equilibrium is detected:

(1) best bent axle master's inclination angle [theta] of engine and the unbalance factor γ that determines according to experiment calculates bent axle master inclination angle [theta] and the pairing vector of unbalance factor γ

$I=0.25M_{\mathrm{rec}}r\sqrt{1+{(1-2\mathrm{\γ})}^2-2(1-2\mathrm{\γ})\cos 2\mathrm{\θ}}$

tan(β-2θ)＝sin2θ/(1-2γ-cos2θ)

Wherein, I is a vector Size, β is a vector

Angle, M _RecBe the reciprocal gross mass of crank connecting link piston assembly, r is a crank length,

Reciprocal gross mass M _Rec=Mp+M _CA

＝Mp+M _L×L _B/L

＝195+200×32.75/105.5

＝257.085g；

The derivation of above-mentioned formula is:

Because suffered the making a concerted effort of bent axle of motorcycle single-barrel engine is periodically variable out-of-balance force, this out-of-balance force is along with the rotation oval in shape (as shown in Figure 3) of bent axle, and the transient equilibrium of bent axle comprises angle of main shaft inclination θ and unbalance factor γ, wherein

Unbalance factor γ=b/ (a+b)

In the formula: the length ratio of the oval major semi-axis of a-

The length ratio of the oval minor semi-axis of b-

Value a+b=1

B=γ then, a=1-γ

Get state I in the bent axle rotation process and state I I analyzes respectively:

State I: establishing the crank angle degree is α, force analysis such as Fig. 4, and the size of making a concerted effort is ka in y1 axle negative direction, is 0 in the x1 direction, obtains equation (1) and equation (2) at x1 axle and y1 direction of principal axis respectively

x1：p _zsin(β+α-θ)-p _j1sinθ＝0 (1)

y1：-p _zcos(β+α-θ)-p _j1cosθ＝ka (2)

In the formula: p _z-rotating inertia force

β-p _zAngle with crank

θ-angle of main shaft inclination

The k-proportionality constant

The length ratio of the oval major semi-axis of a-

p _J1-reciprocal inertia force, p _J1=ω ²RM _RecCos α

The r-crank length

M _Rec-reciprocating part gross mass (comprising piston, piston ring, piston pin, piston pin collar and wrist-pin end of connecting rod quality summation)

State I I: when establishing the crank angle degree and be α+90 °, force analysis such as Fig. 5, the size of making a concerted effort is ka in x1 axle negative direction, is 0 in the y1 direction, obtains equation (3) and equation (4) at x1 axle and y1 direction of principal axis respectively

x1：p _j2sinθ-[-p _zcos(β+α-θ)]＝kb (3)

y1：p _j2cosθ+p _zsin(β+α-θ)＝0 (4)

In the formula: p _J2-reciprocal inertia force, p _J2=ω ²RM _RecSin α

The length ratio of the oval minor semi-axis of b-

Can obtain by (1)～(4) formula:

$\sin (\mathrm{\β}-2\mathrm{\θ})=\left(\sin 2\mathrm{\θ}\right)/\sqrt{1+{(a-b)}^2-2(a-b)\cos 2\mathrm{\θ}}---\left(5\right)$

$\cos (\mathrm{\β}-2\mathrm{\θ})=(a-b-\cos 2\mathrm{\θ})/\sqrt{1-{(a-b)}^2-2(a-b)\cos 2\mathrm{\θ}}---\left(6\right)$

$I=p_z/\left({2\mathrm{\ω}}^2\right)=0.25M_{\mathrm{rec}}r\sqrt{1+{(a-b)}^2-2(a-b)\cos 2\mathrm{\θ}}$

$=0.25M_{\mathrm{rec}}r\sqrt{1+{(1-2\mathrm{\γ})}^2-2(1-2\mathrm{\γ})\cos 2\mathrm{\θ}}---\left(7\right)$

tan(β-2θ)＝(sin2θ)/(a-b-cos2θ)

＝sin2θ/(1-2γ-cos2θ) (8)

We just can calculate the bent axle master inclination angle [theta] and the pairing vector of unbalance factor γ of regulation according to formula (7), (8) (see figure 6).Vector wherein

Size is calculated by formula (7), vector Angle beta is calculated by formula (8).Find the solution vector Known conditions is as shown in the table:

The vector in the table

Known conditions substitution formula (7), (8) just can solve:

I＝3113.6g.mm

β＝172.68°。

(2) find the solution the rotation inertia moment that crank pin place gyrating mass produces

Rotation inertia moment with crank itself Computing formula is:

I ₁＝0.5×Mrot×r，β ₁＝0°

${\stackrel{\→}{I}}_2=\stackrel{\→}{I}-{\stackrel{\→}{I}}_1$

Wherein, I ₁For crank pin place gyrating mass produces rotation inertia moment Size, Mrot is the gyrating mass at crank pin place, r is a crank length, β ₁For crank pin place gyrating mass produces rotation inertia moment

Angle;

Mrot＝M _Q+M _Z+M _LL _A/L

＝265+35+200×72.75/105.5＝437.915g

I ₁＝0.5×Mrot×r＝0.5×437.915×31.1＝6809.58g·mm

β1＝0°

$\stackrel{\→}{I}={\stackrel{\→}{I}}_1+{\stackrel{\→}{I}}_2,$ Can find the solution thus ${\stackrel{\→}{I}}_2=\stackrel{\→}{I}-{\stackrel{\→}{I}}_1$ (see figure 6)

$I_2=\sqrt{{(I\sin \mathrm{\β}-I_1\sin {\mathrm{\β}}_1)}^2+{(I\cos \mathrm{\β}-I_1\cos {\mathrm{\β}}_1)}^2}$

$=\sqrt{{(3113.6\sin 172.68-6809.58\sin 0)}^2+{(3113.6\cos 172.68-6809.58\cos 0)}^2}$

$=9905.75g\·\mathrm{mm}$

tanβ ₂＝(Isinβ-I ₁sinβ ₁)/(Icosβ-I ₁cosβ ₁)

＝(3113.6sin172.68-6809.58sin0)/(3113.6cos172.68-6809.58cos0)

＝-0.04008024

So β ₂=177.705 °

(3) according to the rotation inertia moment of crank itself The rotator inertia square that obtains installing balancing disk on crank is And the quantity of design balancing disk, size and installation site, install for convenient, big balancing disk 1, little balancing disk 2 and mounting screw 3 (see figure 7)s have been designed in the present embodiment, big balancing disk 1 is enclosed within on the crank journal, and little balancing disk 2 is positioned at the crank pin hole of crank and links by mounting screw 3 and big balancing disk 1.The rotator inertia square sum at big balancing disk 1, little balancing disk 2 and 3 pairs of crank up centers of mounting screw ${\stackrel{\→}{I}}_3=-{\stackrel{\→}{I}}_2,$ Its size with Equate the opposite (see figure 6) of direction.Just with a left side (right side) crank complete equipilibrium.This step can be finished with three-dimensional softwares such as UG or ProE.

(4) crank that will assemble balancing disk places and does the transient equilibrium check on the vertical dynamic balancing machine, checks out non-equilibrium site and amount of unbalance, marks;

(5) hole according to being marked on the crank.

For the built-up crank linkage assembly of same specification, after the quantity of balancing disk, size and position design are determined and made, only need transient equilibrium behind the crank correct grinding to detect in the batch process to reuse this balancing disk in the operation just passable.

The sense of rotation of the direction indication bent axle of arrow K among Fig. 3, Fig. 4 and Fig. 5.

Claims (2)

1, a kind of dynamic balance inspection of assembled crank link mechanism of single-cylinder engine is characterized in that comprising the following steps:

(1) best bent axle master inclination angle of engine and the unbalance factor of determining according to experiment calculates the pairing vector of bent axle master inclination angle and unbalance factor:

$I=0.25M_{\mathrm{rec}}r\sqrt{1+{(1-2\mathrm{\γ})}^2-2(1-2\mathrm{\γ})\cos 2\mathrm{\θ}}$

tan(β-2θ)＝sin?2θ/(1-2γ-cos?2θ)

Wherein, I is the vector size, and β is a vector angle, M _RecBe the reciprocal gross mass of crank connecting link piston assembly, r is a crank length, and γ is a unbalance factor, and θ is main inclination angle;

(2) find the solution the rotation inertia moment of crank pin place gyrating mass generation and the rotation inertia moment of crank itself, computing formula is:

I ₁＝0.5×Mrot×r，β ₁＝0°

${\stackrel{\→}{I}}_2=\stackrel{\→}{I}-{\stackrel{\→}{I}}_1$

Wherein, I ₁Be the size of crank pin place gyrating mass generation rotation inertia moment, β ₁Be the angle of crank pin place gyrating mass generation rotation inertia moment, Mrot is the gyrating mass at crank pin place, and r is a crank length, Rotation inertia moment for crank itself;

(3), obtain on crank, to install the rotator inertia square of balancing disk, and design quantity, size and the installation site of required balancing disk when detecting according to the rotation inertia moment of crank itself;

(4) crank that will assemble balancing disk places and does the transient equilibrium check on the vertical dynamic balancing machine, checks out non-equilibrium site and amount of unbalance, marks;

(5) hole according to being marked on the crank.

2, dynamic balance inspection of assembled crank link mechanism of single-cylinder engine according to claim 1, it is characterized in that described balancing disk is made up of big balancing disk (1), little balancing disk (2) and mounting screw (3), big balancing disk (1) is enclosed within on the crank journal, and little balancing disk (2) is positioned at the crank pin hole of crank and links by mounting screw (3) and big balancing disk (1).

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