CN101482166A - Differential gear used for power coupling apparatus of hybrid power vehicle - Google Patents

Abstract

The invention discloses a differential mechanism used for a power coupling device of a hybrid vehicle, aiming at solving the problem that the satellite gear, and the bevel gear of the differential mechanism is incorrectly meshed caused by the serious slipping wear between the satellite gear (3) and the satellite gear shaft (4) of the differential mechanism due to overrunning in the prior art. The differential mechanism comprises a differential shell (1), a left bevel gear (2), the satellite gear (3), the satellite gear shaft (4), a runner axle (5) and a right bevel gear (6). The additionally arranged runner axle (5) is uniformly arranged between the shaft hole of the satellite gear (3) and the shaft end of the satellite gear shaft (4) of the differential mechanism; the symmetrical axis of the runner axle (5) is parallel to the symmetrical axis of the satellite gear shaft (4) and the symmetrical axis of the shaft hole of the satellite gear (3); the cylindrical surface of the runner axle (5), the cylindrical surface of the shaft end of the satellite gear shaft (4) inside the runner axle (5), and the inner cylindrical surface of the shaft hole of the satellite gear (3) of the differential outside the runner axle (5) are simultaneously contacted and connected in a rolling way.

Description

Differential mechanism as power coupling apparatus of hybrid power vehicle

Technical field

The present invention relates to a kind of dynamic coupling device of hybrid vehicle, more particularly, the present invention relates to a kind of differential mechanism as power coupling apparatus of hybrid power vehicle.

Background technique

Energy-conservation and environmental protection is the two principal themes of 21 century development of automobile, electric vehicle is the ideal substitute of traditional oil-burning internal combustion engine automobile, but be subjected to the restriction and the expensive constraint of fuel cell of storage battery energy, hybrid vehicle can be considered a kind of feasible program that comprehensively addresses the above problem.Hybrid vehicle is to provide power by two or more power source, and current commonplace scheme is to adopt motor and motor, generator to make up.How realizing the power distribution between hybrid electric vehicle engine and motor, the generator, is one of development hybrid vehicle key issue that must solve.

Utilize the dynamic coupling device of differential mechanism as Hybrid Vehicle, can realize hybrid vehicle continuous type series parallel connection drive form, rotating speed, torque by regulator generator can make engine operation at best efficiency point, thoroughly solve conventional engines because the problem of the operation point inefficiency that causes with the mechanical connection of wheel, thereby realized the control performance of electronic stepless continuous speed change (ECVT).Utilize the motor of high torque (HT) characteristic to realize the increase torque function of traditional speed changer, can eliminate mechanisms such as speed changer, clutch, the car load power transmission system is greatly simplified.By reasonable control generated output power, can realize the function of real-time regulated battery SOC (state of charge) in the driving process.

Because the planetary pinion rotation rotating speed of automobile tradition differential mechanism is less, and run duration is shorter, therefore no any connected element between the planetary pinion of automobile tradition differential mechanism and the planet pin, the sliding wear when only depending between the two ransaxle lubricant oil just can improve its relative movement.The lubricating method that is proposed at present comprises: suitably increase the matching gap of differential mechanism component, increase the pressure angle on hole and the axle Line of contact, form effective wedge gap, promote oil film to form; On differential gear, planet tooth and cross axle, increase oil duct, make the rapid engaging friction of the oil droplet that splashes surface, constitute lubricated preferably environment; Gear shaft is carried out phosphatization handle, guarantee initial lubricated break-in; Install fluid delivery system additional, utilize the controllable pressure controlling mechanism that differential mechanism is lubricated; Lubricating oil bath is set, guarantees lubricated.

But when traditional differential mechanism is used as power coupling apparatus of hybrid power vehicle, there is big speed discrepancy all the time in output semiaxis about it, differential pinion gear and planet pin rely on above-mentioned lubricating method can only keep relatively rotating of short time, otherwise serious sliding wear between the two can appear, cause the incorrect engagement of differential pinion gear and differential gear, even gear teeth damage appears, not only greatly reduces the life-span of differential mechanism, and influences the normal transmission of power of automobile.In the present patented invention, the lubrication problem when all differential mechanism not being used as power coupling apparatus of hybrid power vehicle proposes a solution.

Summary of the invention

Technical problem to be solved by this invention is to overcome traditional differential mechanism that prior art exists to cross long-play and serious sliding wear between the planetary pinion of differential mechanism and the planet pin can occur and cause the planetary pinion of differential mechanism and the problem of the incorrect engagement of differential gear, and a kind of differential mechanism that is used as dynamic coupling device that can become hybrid vehicle is provided.

For solving the problems of the technologies described above, the present invention adopts following technological scheme to realize: the differential mechanism as power coupling apparatus of hybrid power vehicle comprises differential casing, left half axle gear, right axle shaft gear, planetary pinion and planet pin, and planetary pinion is set in the end of planet pin.Between planetary gear shaft hole and planet pin axle head, needle roller is installed equably, the axis of symmetry of needle roller is parallel with the axis of symmetry of the axis of symmetry of planet pin and planetary gear shaft hole, and the cylndrical surface of needle roller is connected for the rolling that contacts simultaneously with the cylndrical surface of needle roller inner planet geear axle axle head and the inner cylindrical surface of needle roller outer planet gear axis hole.

Axial end at the planet pin of described differential mechanism in the technological scheme is processed with the shaft shoulder that prevents that needle roller from coming off, promptly at ring groove that cross section is a rectangle of planet pin axial end processing, the axis of symmetry conllinear of the axis of symmetry of ring groove and planet pin; What described planet pin adopted is d-axis or cross oblique crank Z; The described needle roller of installing equably between planetary gear shaft hole and planet pin axle head can be replaced by needle bearing.

Compared with prior art the invention has the beneficial effects as follows:

1. utilize the improvement on traditional differential design, realized differential mechanism is used as the dynamic coupling device of hybrid vehicle, thereby simplified the brand-new design and the trial-production of power coupling apparatus of hybrid power vehicle greatly, save time, save expense.

2. the present invention is improved to rolling friction with the axle head cylndrical surface of traditional differential spider pinion shaft and the sliding friction between the planetary axis hole inner cylindrical surface, can effectively improve the restriction of traditional differential mechanism maximum (top) speed difference, make speed discrepancy between traditional differential mechanism left and right half gear surpass 2500rpm and the serious sliding wear situation of former traditional differential mechanism can not occur, to satisfy it fully as the demand of power coupling apparatus of hybrid power vehicle to rotating speed.And can also effectively transmit the desired torque of car load power character, make traditional differential mechanism after the improvement can be effectively, reliable delivery power.

Description of drawings

The present invention is further illustrated below in conjunction with accompanying drawing:

Fig. 1 is the structural representation as the differential mechanism of power coupling apparatus of hybrid power vehicle;

Fig. 2 is the free-body diagram as the planet pin of direct shaft type in the differential mechanism of power coupling apparatus of hybrid power vehicle;

Among the figure: 1. differential casing, 2. left half axle gear, 3. planetary pinion, 4. planet pin, 5. needle roller, 6. right axle shaft gear.

Embodiment

Below in conjunction with accompanying drawing the present invention is explained in detail:

Consult Fig. 1, differential mechanism as power coupling apparatus of hybrid power vehicle of the present invention is the improvement design of traditional differential mechanism having been carried out partial structurtes, specifically, for the friction duty during relative running up between the axle head of planetary pinion 3 axis holes that improve differential mechanism and planet pin 4, between the axle head of planetary pinion 3 axis holes of differential mechanism and planet pin 4, some and a certain size needle roller 5 are installed equably.The axis of symmetry of needle roller 5 should be parallel with the axis of symmetry of planetary pinion 3 axis holes with the axis of symmetry of planet pin 4 when being provided with, and the inner cylindrical surface of the cylndrical surface of the cylndrical surface of needle roller 5 and needle roller 5 inner planet geear axles 4 axle heads and planetary pinion 3 axis holes of needle roller 5 outside differential mechanisms should make contact to simultaneously to roll and be connected.Work better in order to make this structure, planetary pinion 3 axis holes and planet pin 4 axle heads of reply differential mechanism, promptly heat-treat processing to planetary pinion 3 axis holes of differential mechanism with to planet pin 4 parts that match with planetary pinion 3 axis holes, make the axis hole of planetary pinion 3 of differential mechanism and the hardness of planet pin 4 axle heads reach HRC60, the axis hole of the planetary pinion 3 of increase differential mechanism and the hardness of planet pin 4 axle heads, be complementary with the hardness (HRC60) of needle roller 5, thereby increased using effect and the life-span that is used as the differential mechanism of power coupling apparatus of hybrid power vehicle.Axial end at the planet pin 4 of differential mechanism is processed with the shaft shoulder that prevents that needle roller 5 from coming off on the other hand.Just at ring groove that cross section is a rectangle of axial end processing of the planet pin 4 of differential mechanism, the axis of symmetry of the axis of symmetry of ring groove and planet pin 4 is wanted conllinear.The planet pin 4 of differential mechanism is that to be the criss-cross axle that intersects vertically be cross oblique crank Z (being used on the large and medium-sized car) for a d-axis (being used on the compact car) or one under the general situation.Just process a ring groove that structure is identical with size respectively for d-axis at the place, two ends of d-axis, and just should process a ring groove that structure is identical with size respectively at criss-cross four axle heads that intersect vertically axle for the cross oblique crank Z, cited design-calculated embodiment adopts the differential mechanism of a d-axis among the present invention.Needle roller 5 is installed in the ring groove so as not to during the differential mechanism operation needle roller 5 between the axle head of the axis hole of planetary pinion 3 and planet pin 4, come off.The axis hole that becomes planetary pinion 3 by original being slidingly connected that is connected between the axle head of the axis hole of planetary pinion 3 and planet pin 4 is connected with the rolling of needle roller 5 respectively with the axle head of planet pin 4 like this, friction law during relative the running up of axle head of this axis hole that will improve planetary pinion 3 widely and planet pin 4 avoids occurring serious sliding wear problem.

The model of producing with China No.1 Automobile Group Co is that the differential mechanism of CA6440 is how the example explanation becomes its improvement the differential mechanism as power coupling apparatus of hybrid power vehicle below:

This differential mechanism includes the planet pin 4 and right axle shaft gear 6 of differential casing 1, left half axle gear 2, planetary pinion 3, direct shaft type, before the architecture advances design, the two ends that 2 planetary pinions 3 shaft hole sleeve by the core wheel place is contained in the planet pin 4 of direct shaft type become to be slidingly connected.After the architecture advances design, between the axle head of the axis hole of planetary pinion 3 and planet pin 4, evenly be provided with the needle roller of some.How are the size of needle roller and quantity selected?

1. the design alternative of needle roller Dimensions and quantity

Consult Fig. 1, the Dimensions of needle roller 5 is a principle in line with selecting the less needle roller of diameter as far as possible on the basis of satisfying load that needle roller 5 bears and rotary speed property, the final Dimensions of needle roller 5 of selecting is: the diameter of needle roller 5: 2mm, the length of needle roller 5: 20mm, the interior raceway diameter of needle roller 5 (being the diameter of axle behind the axle head processing ring groove of planet gear shaft 4): φ 15mm.Adopt the quantity of needle roller 5 to improve the load carrying capacity of needle roller, and guarantee rational gap, can be beneficial to needle roller 5 proper functioning and prolong working life of needle roller with full needle construction.Minimum clearance between the general recommendation needle roller 5 is 0.025mm, and the maximum value of total backlash amount is (0.5～0.7) d _z, d _zDiameter for needle roller 5.According to this experience, choose that each parameter of needle roller is between planetary pinion 3 and the planet pin 4: the diameter of needle roller 5: d _z=2mm, the number Z=31 of needle roller 5, the effective length L of needle roller 5 _We=20mm, the gap s=0.27mm between the needle roller 5.

2. the designing and calculating of planet pin

According to each parameter of selected needle roller 5, the planet pin 4 of differential mechanism is φ 15 with the mating part diameter of the planetary pinion 3 of differential mechanism, and remaining part keeps φ 19, and the axis hole degree of depth of planetary pinion 3 is 21mm.The raw material that planet pin 4 adopts: 2OCrMnTi.

Because planet pin 4 local diameter attenuate, so fibrous root according to the size of above-mentioned planet pin 4 and the structural parameter of former each parts of car differential mechanism, carries out shear strength and flexural strength check to the planet pin 4 after the remodeling.

Consult Fig. 2, analyze the stressed of planet pin 4.Because differential casing 1 torque T _jEffect, produce corresponding tangential force F at the two ends of planet pin 4 ₀, and T _j=F ₀L '.Simultaneously, planet pin 4 is bearing the tangential force F from planetary pinion 3 at work _r

According to equalising torque:

F ₀L′+F _rL ₀＝F _r(L′-L ₀)

So:

$F_r=\frac{F_{0}L\′}{L\′-2L_0}$

From the force analysis of differential casing 1 as can be known:

T _j＝F ₀L′

So:

$F_r=\frac{T_j}{L\′-{2L}_0}$

In the formula:

T _j-being delivered to torque on the differential casing 1 by the driven planetary pinion of main reducing gear, unit is Nm, Engine torque of the present invention is directly imported the differential coupled system, so T _j=102 units are Nm.

Distance between L '-planet pin two ends force bearing point, unit is mm

L ₀-F _rPoint of force application is apart from the distance of planetary pinion shaft end force bearing point, and unit is mm.

Planet pin 4 axle journal roots, i.e. the flexural stress σ at section variation place _wτ is respectively with shearing stress:

$\mathrm{\τ}=\frac{F_r}{A}=\frac{{4F}_r}{{{\mathrm{\πd}}_2}^2}=70.896$ Unit is MPa

${\mathrm{\σ}}_w=\frac{M}{W}=\frac{{32F}_0{L}_0}{{{\mathrm{\πd}}_2}^3}=84.6$ Unit is MPa

In the formula:

M-suffered the moment of flexure of calculating section part planet pin, unit is Nm

The bending resistant section coefficient of W-axle, $W=\frac{{\mathrm{\πd}}^3}{32}\≈{0.1d}^3$

d ₂-planet pin and needle roller cooperation place diameter, unit is mm.

Planet pin 4 is made by the 2OCrMnTi low-carbon alloy steel, through carburizing and quenching, and surface hardness HRC58-65.Its shearing stress should be not more than 80～120MPa.This shows, improve the planet pin of processing after the design and satisfy the shear strength requirement.

Through tabling look-up the permissible bending stress [σ of 2OCrMnTi low-carbon alloy steel _w]=291～315MPa.As seen, satisfy the flexural strength requirement of axle.

In sum, although the planetary pinion shaft diameter behind the remodeling diminishes, turn round parts and directly act on differential mechanism, so the planet pin 4 that improves after the design satisfies requirement of strength fully because Engine torque increases without any deceleration.

3. needle roller life-span verification

According to " mechanical design handbook " middle (center) bearing Calculation for life formula, the verification needle roller life-span:

$L_{10h}=\frac{{10}^6}{60n}{\left(\frac{C}{P}\right)}^{\mathrm{\ϵ}}$

In the formula:

L _10hIn the working life of-needle roller, unit is h

The dynamic load rating of C-needle roller, unit are N

The equivalent dynamic load of P-needle roller, unit is N, needle roller only bears pure radial load herein, so P=F _r

The rotating speed of n-needle roller, unit are r/min

ε-life index, ε=10/3

The rotation speed n of needle roller, i.e. planet gear speed of autorotation by differential mechanism is carried out the rotation speed relation analysis, has:

$n=\mathrm{\Δn}\frac{Z_2}{{2Z}_1}$

In the formula:

Δ n-two-semiaxle gear rotational speed is poor, and unit is r/min

Z ₁-planetary pinion the number of teeth

Z ₂-differential gear the number of teeth

Poor according to two-semiaxle gear mean speed, the average speed of autorotation of calculating planetary pinion is:

$n=\mathrm{\Δn}\frac{Z_1}{{2Z}_2}=1022\frac{16}{2\×11}=744r/\min$

The dynamic load rating of needle roller:

C＝f _c(iL _wecosα) ^7/9Z ^3/4d _z ^29/27

In the formula:

f _c-coefficient is through tabling look-up f _c=84.2

I-rolling element columns, i=1

α-wrapping angle, α=0

With selected needle roller parameter substitution following formula, calculate C=23936N.

Finally, calculating needle roller is working life:

$L_{10h}=\frac{{10}^6}{60n}{\left(\frac{C}{P}\right)}^{\mathrm{\ϵ}}=55125,$ The h of unit

The L in working life of needle roller _hCan be by automobile with average speed v _AmThe total kilometres S that travels to overhaul calculates:

$L_h=\frac{S}{v_{\mathrm{am}}},$ The h of unit

The desirable v of average speed in the formula _Am≈ 0.6v _Max, be 160km/h by highest speed, S=200000km calculates L _h=21h.As seen meet the demands the working life of needle roller.

4. planetary pinion flank of tooth contact fatigue strength is checked

Because planetary pinion often only plays the equiarm track bar in the work of automobile differential, therefore differential gear is mainly carried out flexural strength and calculate, to then not considering fatigue life.But when as the mixed power coupled system,, check so must carry out fatigue strength to planetary pinion owing to there is bigger speed discrepancy always.

For bevel gear, and two bevel gear axis angle of cut ∑=90 are when spending according to " mechanical design handbook ", and flank of tooth contact fatigue strength is:

${\mathrm{\σ}}_H=\sqrt{\frac{F_t{K}_A{K}_V{K}_{\mathrm{H\β}}{K}_{\mathrm{H\α}}\sqrt{u^2+1}}{0.85{\mathrm{bd}}_{m1}u}}\×Z_H{Z}_E{Z}_{\mathrm{\ϵ\β}}{Z}_K$

Wherein, K _A-coefficient of utilization; K _V-Dynamic factor; F _tThe tangential force of-planetary pinion mid point standard pitch circle; K _{H β}-teeth directional load distribution coefficient; K _{H α}-between cog load distribution coefficient; $u=\frac{z_2}{z_1};$ The b-facewidth; d _M1The average standard pitch diameter of-planetary pinion; Z _H-node region coefficient; z _E-elasticity coefficient; Z _{ε β}-contact ratio coefficient.Z _K-bevel gear coefficient.

Allowable contact stress:

${\mathrm{\σ}}_{\mathrm{HP}}=\frac{{\mathrm{\σ}}_{\mathrm{Hlim}}}{S_{H\min }}\×Z_N{Z}_{\mathrm{LvR}}{Z}_X{Z}_W$

Wherein, σ _HlimThe contact fatigue strength limit of-test gear; S _Hmin-safety coefficient; z _N-Life factor, Z _LvR-lubricant film influence coefficient; Z _X-Size factor; Z _W-work hardening coefficient.

Because the precision prescribed of automobile differential gear tooth is lower, so the extensive use of finish forge differential gear process quilt.According to investigation, the machining accuracy parameter of automobile differential planetary pinion, differential gear is at present: tooth-face roughness Ra0.8, grade of accuracy 8-GB11365.In conjunction with planetary machining accuracy grade,, calculate flank of tooth contact fatigue strength σ according to relevant planetary pinion physical dimension formula and method _H=1706MPa, allowable contact stress σ _HP=1710MPa, as seen, σ _H＜σ _HP, promptly, can satisfy planetary pinion requirement fatigue life of hybrid vehicle differential coupled system with current planetary processing method and machining accuracy because there is higher rotation speed in the planetary pinion of differential coupled system.

The present invention one is intended to illustrate the feasibility of differential coupled system and architecture advances design thereof, the 2nd, verify that by test the planetary pinion of current differential mechanism can satisfy test requirements document fatigue life.The differential mechanism that is used as power coupling apparatus of hybrid power vehicle of the present invention is when Industry Promotion, and then above-mentioned computer program, calculating content and strength check etc. all can be used as to Industry Promotion and improve design and accurately machined analysis foundation.

5. conclusion

The analysis showed that by above-mentioned, traditional differential mechanism is carried out partial structurtes improve design, between differential pinion gear and planet pin, assemble needle roller, the serious sliding wear problem that traditional differential mechanism occurs when the hybrid vehicle dynamic coupling system be can solve, the loss of automobile power transmission efficiency and the minimizing in differential mechanism working life avoided.

By above-mentioned improvement design and calculating, the one, we are promptly processed needed one group of needle roller, be installed in equably between the axle head of the axis hole of planetary pinion 3 and planet pin 4, producing can be as the differential mechanism of power coupling apparatus of hybrid power vehicle.The 2nd, when no matter our one group of designed needle roller still is can be substituted by the needle bearing of standard on size from bearing capacity, needle bearing that so also can selection standard, the needle bearing of standard is installed between the axle head of the axis hole of planetary pinion 3 and planet pin 4, a kind of differential mechanism as power coupling apparatus of hybrid power vehicle is provided equally.

Claims (4)

1. differential mechanism as power coupling apparatus of hybrid power vehicle, comprise differential casing (1), left half axle gear (2), right axle shaft gear (6), planetary pinion (3) and planet pin (4), planetary pinion (3) is sleeved on the end of planet pin (4), it is characterized in that between planetary pinion (3) axis hole and planet pin (4) axle head, needle roller (5) being installed equably, the axis of symmetry of needle roller (5) is parallel with the axis of symmetry of planetary pinion (3) axis hole with the axis of symmetry of planet pin (4), and the cylndrical surface of needle roller (5) is connected for the rolling that contacts simultaneously with the cylndrical surface of needle roller (5) inner planet geear axle (4) axle head and the inner cylindrical surface of needle roller (5) outer planet gear (3) axis hole.

2. according to the described differential mechanism of claim 1 as power coupling apparatus of hybrid power vehicle, it is characterized in that planet pin (4) axial end at differential mechanism is processed with the shaft shoulder that prevents that needle roller (5) from coming off, promptly at ring groove that cross section is a rectangle of planet pin (4) axial end processing, the axis of symmetry conllinear of the axis of symmetry of ring groove and planet pin 4.

3. according to the described differential mechanism as power coupling apparatus of hybrid power vehicle of claim 1, what it is characterized in that described planet pin (4) employing is d-axis or cross oblique crank Z.

4. according to the described differential mechanism as power coupling apparatus of hybrid power vehicle of claim 1, it is characterized in that between planetary pinion (3) axis hole and planet pin (4) axle head the needle roller (5) of installation can be replaced by needle bearing equably.

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