CN1168954A - Hydraulic planetary differential stepless automatic speed variator - Google Patents

Abstract

The hydraulic planetary differential stepless automatic speed variator mainly consists of hydraulic torque converter and single rowThe planetary wheel is composed of a sun wheel 13, a planetary wheel 7, a gear ring 14, a pump wheel 3 and a turbine 2, and the turbine can rotate at the same speed or at different speeds. The ratio of the input torque to the output torque is

The output shaft speed may be continuously increased from zero to the input shaft speed. Thereby making it simpler, less costly, and less power consuming. The torque converter has all functions of the torque converter, the input-output torque ratio and the torque conversion capacity are both much larger than those of the torque converter, and the reverse input-output torque ratio is also close to the maximum value of the forward gear.

Description

Stepless and automatic hydraulic planetary differential speed variator

Hydraulic planetary automatic transmission in automobile and the engineering machinery develops into today, and using has been the comparison perfection, but it really makes the structure of speed changer become complicated all the more, number of parts rolls up, accuracy of manufacturing is high, and maintenance is complicated more, and cost also significantly improves.For speed changer is become simply, and remove the self shifter process from, output shaft rotating speed and moment of torsion can be changed continuously,, reduce cost so that reduce power consumption.I have designed stepless and automatic hydraulic planetary differential speed variator (abbreviation CVT (continuously variable transmission)).It mainly is made up of single planet wheel and hydraulic moment changeable, pump impeller wherein, and turbine can rotate by differential, also can rotate with speed.Increase or reduce the output shaft rotating speed to reach, reduce or increase output torque, the purpose that the conversion output shaft turns to.It is a continuous stepless in the output speed variation of forward gears, and changes automatically with the variation of the suffered resisting moment of output shaft.Because of there not being shift process also just not have automatic shift system, CVT (continuously variable transmission) has all functions of fluid torque converter, and torque ratio and bending moment ability are all big many than torque-converters, even if the torque ratio of reverse gear also with advance grade Maximum Torque than close.

One, the basic transmission principle of CVT (continuously variable transmission)

By the basic transmission principle figure of CVT (continuously variable transmission) that schemes () as seen, the torque-converters front end is provided with lock-up clutch 1, pump impeller 2 is connected as a single entity by gear oil pump 3 and sun gear 9, but the axle rotation of planet wheel 5 windings on planet carrier 8, follow rest 8 revolution again simultaneously, its inner and sun gear 9 engagements, outer end and gear ring 10 engagements.The rotating plate of drive clutch 6 and turbine 7 are connected as a single entity, and are connected as a single entity by moving plate and planet carrier, and lock-up solenoid valve switch 12 is driven by centrifugal mechanism 11, so that the locking timing of control lock-up clutch.Brake drum on the planet carrier 8 is provided with reverse gear clamping strap 4 outward, so that carry out reverse drive.When clamping strap 4 loosens, when drive clutch 6 engages, pump impeller 2 rotations, oil pump gear 3 and sun gear 9 rotate with speed with it.Turbine 7 and planet carrier 8 rotates with speed, because sun gear 9 exists speed discrepancy with planet carrier 8, makes planet wheel 5 axial rotation again when rotating with planet carrier 8, and its speed of autorotation reduces and reduces with the speed discrepancy of sun gear 9 and planet carrier 8.And the speed of autorotation of road wheel 5 is more little, and gear ring 10 rotating speeds are high more, and planet carrier 8 is also more little with the speed discrepancy of sun gear 9.The rotating speed of gear ring 10 can be zero, also can be fast together with sun gear 9.With when speed, planet row, the torque-converters rotation that becomes one.To make it be in rotating speed lower or when leveling off to zero state when gear ring 10 suffered cloudy moments are big, the rotating ratio minimum of pump impeller 2 and turbine 7, the torque ratio maximum of torque-converters, and this moment sun gear 9 feedback moment also maximum.Under the certain condition of applied moment, because the torque-converters input torque increases to maximum, and torque ratio reaches maximum value, thereby cause the turbine 7 and the gear ring 10 output torque maximums of torque-converters, this moment, the input output moment ratio of CVT (continuously variable transmission) can reach (pump impeller 2 is as input, and gear ring 10 is as output) $K_{\mathrm{mx}}=\frac{(2R_g+R_u)U_{\max }}{2(R_g+R_a)-R_a{U}_{\max }}$ Along with gear ring 10 suffered resisting moment reduce gradually, gear ring 10 rotating speeds are improved gradually.Under the certain condition of pump impeller 2 rotating speeds, make turbine 7 again, planet carrier 8 rotating speeds improve gradually, and then cause pump impeller 2, and sun gear 9 and turbine 7, the speed discrepancy of planet carrier 8 reduces, be that speed ratio increases, the feedback moment of sun gear 9 is gradually little, and the torque ratio of torque-converters reduces gradually, and gear ring 10 output torques also reduce gradually like this.When gear ring 10 and sun gear 9 speed rotation together, promptly pump impeller 2, and when turbine 7 sun gears 9, planet carrier 8, gear ring 10 became one with the speed rotation, gear ring 10 output torque minimums equaled input torque.At this moment the torque ratio of torque-converters is 1, and the feedback moment of sun gear 9 is not amplified by torque-converters, just reciprocation cycle in as the loop of figure (four).CVT (continuously variable transmission) increases and increases automatically with the suffered resisting moment of output shaft in the output torque of forward gears in sum, reduces and reduces automatically with the suffered resisting moment of output shaft.The output shaft rotating speed then reduces with its suffered resisting moment and automatically increases, and increases and reduces automatically with its suffered resisting moment.Under the certain condition of input shaft rotating speed, the output shaft rotating speed can increase to the input shaft rotating speed continuously by zero.When the speed ratio of pump impeller 2 and turbine 7 near 1 the time, centrifugal mechanism 11 drives electromagnetic valve switch 12, makes lock-up clutch 1 locking to reduce energy loss.And when the speed ratio of pump impeller 2 and turbine 7 less than 1 the time, centrifugal mechanism 11, electromagnetic valve switch 12, self-return is thrown off lock-up clutch 1.When reverse gear clamping strap 4 was held star frame 8 tightly, 9 of sun gears were driving wheel, because of planet carrier 8 maintains static oppositely deceleration rotation of gear ring 10.

Two, the control of CVT (continuously variable transmission)

The hydraulic circuit of CVT (continuously variable transmission) as figure (two) shown in, torque-converters hydraulic circuit wherein, by the bending moment type decided, this paper repeats no more.But the pin of lock-up clutch ends timing then to be driven by the centrifugal mechanism 11 of figure (), electromagnetic valve switch 12 controls.The block selecting process is then controlled by selectro valve, guiding valve in figure (three) selectro valve can horizontally slip, and it has three left alone without help positions of staying is that " advancing ", " sky ", " falling " its mesopore 1 are communicated with oil pump, and hole 2 is that relief hole is communicated with oil sump, hole 3 is communicated with brake cylinder, and hole 4 is communicated with clutch oil cylinder.When selectro valve is in the forward position of figure a, the fluid warp of oil pump, hole 1 and hole 4 are added in the clutch oil cylinder, make clutch, even turbine and planet carrier are connected as a single entity.And the interior fluid of brake cylinder passes through hole 3 and hole 2 pressure releases already to oil sump, does not have oil in the brake cylinder thereby make, and clamping strap loosens, and power is by the turbine of torque-converters at this moment, and planet carrier passes to gear ring and exports.When selectro valve was in the neutral position of figure b, brake cylinder and clutch oil cylinder all were communicated with relief hole 2 by hole 3 and hole 4, thereby clamping strap are loosened, and turbine separates with planet carrier, and each member freely rotates among the whole planet row, but gear ring 10 transfixions.When selectro valve was in the reverse gear position of figure c, clutch oil cylinder was communicated with relief hole 2 by hole 4, and the break oil cylinder is communicated with hole 1 and oil pump by hole 3, makes fluid charge into the break oil cylinder, and clamping strap is fixed planet carrier.Because the oil circuit in hole 3 and hole 4 is provided with the branch road that is communicated with relief hole 2, and solenoid valve cuts out it on this pressure release branch road.When stepping on brake petal, solenoid valve is just open-minded with this pressure release branch road, thereby clutch 6 is separated, and break 4 loosens, and is in neutral state during the speed changer prison.Lift brake petal, solenoid valve cuts out this pressure release branch road again, makes speed changer recover former gear.

Three, the moment of CVT (continuously variable transmission) and rotating speed analysis

By figure (one) as can be known CVT (continuously variable transmission) be M at the input torque of forward gears, output torque M _bFeedback moment M _aTransmit along path shown in figure (four), this shows that this speed changer is that differential feedback cycle increases the square formula, and press following formula and distribute:

(M+M _a) U=M _a+ M _b(1) U is the torque ratio of torque-converters in the formula.

Because this moment, planet carrier was driving link, gear ring, sun gear are Passive part, so planet wheel and sun gear are stressed shown in figure (five), wherein:

P _a---sun gear is to the active force of planet wheel

P _b---gear ring is to the active force of planet wheel

P _g---planet wheel is to the active force of sun gear

P _h---planet carrier is to the active force of planet wheel

M _h--the active moment of-planet carrier

R _a---sun gear radius

R _b---gear ring radius

R _g---planet wheel radius is because P _b=P _a=-P _g

P _h＝P _a+P _b＝2P _a

M _a＝P _gR _a＝P _aR _a (2)

M _h＝P _h(R _g+R _a)＝2P _a(R _g+R _a) (3)

M _b＝P _bR _b＝P _a(2R _g+R _a) (4)

(1) (2) (3) formula is divided by respectively $\frac{M_b}{M_a}=\frac{2R_g+R_a}{R_a}----\left(5\right)$ $\frac{M_h}{M_a}=\frac{2(R_g+R_a)}{R_a}----\left(6\right)$ $\frac{M_h}{M_b}=\frac{2(R_g+R_a)}{2R_g+R_a}----\left(7\right)$

(5) formula explanation feedback moment M _aMuch smaller than gear ring output torque M _bAnd with M _bIncrease and decrease and increase and decrease.

(5) formula is deformed into $M_a=\frac{R_a{M}_b}{2R_g+R_a}$

And in substitution (1) formula $\mathrm{MU}+\frac{R_a{M}_{b}U}{2R_g+R_a}=\frac{R_a{M}_b}{2R_g+R_a}+M_b$

The input output torque ratio K that can get CVT (continuously variable transmission) after arrangement is: $K=\frac{M_b}{M}=\frac{(2R_g+R_a)U}{2(R_g+R_a)-R_{a}U}----\left(8\right)$

(8) formula explanation K value is relevant with the torque ratio U of planet row's relating to parameters and torque-converters, and after planet row parameter was determined, the K value only changed with the U value, and when the U minimum equaled 1, K value also minimum equaled 1.Because the K value is directly proportional with the U value, and the torque ratio U of torque-converters and pump impeller, the speed ratio of turbine is relevant, and by the torque-converters performance characteristic of figure (six), speed ratio E is more little as can be known, and the U value is big more, and the big more U value of E value is more little, and when E equaled 1, U also equaled 1.At forward gears, because planet carrier and turbine are connected as a single entity, pump impeller and sun gear are connected as a single entity, and again owing to each member among the planet row is differential, so know the rotation speed relation of each member easily are $N_h=I_{\mathrm{ha}}^b{N}_a=I_{\mathrm{hb}}^a{N}_b----\left(9\right)$ N in the formula _a--the sun gear rotating speed

N _h--the planet carrier rotating speed

N _b--gear ring rotating speed velocity ratio is respectively $I_{\mathrm{ha}}^b=\frac{1}{I_{\mathrm{ah}}^b}=\frac{1}{1-I_{\mathrm{ab}}^h}=\frac{1}{1-\left(\frac{-R_b}{R_a}\right)}=\frac{R_a}{R_b+R_a}$ $I_{\mathrm{hb}}^a=\frac{1}{I_{\mathrm{bh}}^a}=\frac{1}{1-I_{\mathrm{ba}}^h}=\frac{1}{1-\left(\frac{-R_a}{R_b}\right)}=\frac{R_b}{R_b+R_a}$ Therefore (9) formula can be write as $N_h=\frac{N_a{R}_a}{R_b+R_a}+\frac{N_b{R}_b}{R_b+R_a}----\left(10\right)$

Work as N _b(10) formula that levels off to zero time can be write as $N_h=\frac{N_a{R}_a}{R_a+R_b}----\left(11\right)$ Illustrate that planet carrier should be more than or equal to (11) formula as the minimum speed of driving link.Under the certain condition of sun gear rotating speed, with N _hFurther increase, N _bThen, press the continuous increase that (10) formula rule is directly proportional by zero beginning.

Work as N _a=N _hShi Yiding has

N _a=N _bEach member is integral with the speed rotation among pump impeller, turbine, the planet row at this moment.

With (10) formula two ends be with removing Na, can getting the torque-converters speed ratio $E=\frac{N_h}{N_a}=\frac{R_a}{R_b+R_a}+\frac{R_b{N}_b}{(R_b+R_a)N_a}----\left(12\right)$ Work as the gear ring rotational speed N as can be known by (12) formula _bLevel off to and to get the minimum speed ratio E of torque-converters zero the time _MimFor $E_{\mathrm{mim}}=\frac{R_a}{R_b+R_a}$ By scheming (six) E as can be known _MimPairing U value is maximum, and the maximum ratio that can be got the output input torque of stepless automatic transmission by (8) formula is: $K_{\max }=\frac{(2R_g+R_a)U_{\max }}{2(R_g+R_a)-R_a{U}_{\max }}----\left(13\right)$

Work as N _b=N _aThe time torque-converters speed ratio be to the maximum

E _max＝1

By figure (six) as can be known U value minimum be 1

By (8) Shi Kede

K _mim＝1

Work as N _h(10) formula can be write as in=0 o'clock $\frac{N_a}{N_b}=-\frac{R_b}{R_a}----\left(14\right)$

This moment, sun gear was that the driving link gear ring is then by the rotation of oppositely slowing down of (14) formula rule.Its output input torque ratio is $K_d=\frac{M_b}{M_a}=\frac{R_b}{R_a}=\frac{2R_g+R_a}{R_a}----\left(15\right)$ If the R among the CVT (continuously variable transmission) planet row _a=25 R _g=30 R _b=85

And can get the minimum speed ratio of pump impeller, turbine that the gear ring revolution levels off to zero time when joining single-stage quaternary part (Allison) torque-converters and be: $E_{\mathrm{mim}}=\frac{R_a}{R_b+R_a}=\frac{25}{85+25}\≈0.227$

By figure (six) the torque-converters performance characteristic as can be known its corresponding Maximum Torque ratio be

U _max≈2.5

Can get CVT (continuously variable transmission) by (13) formula at the maximum input output torque ratio of forward gears is $K\max =\frac{(2R_g+R_a)U\max }{2(R_g+R_a)-R_{a}U\max }=\frac{2.5(2\×30+25)}{2(30+25)-25\×2.5}=4.47$

Can get reverse gear input output moment specific force by (15) formula $K_d=\frac{R_b}{R_a}=\frac{85}{25}=3.4$

In design, will become as far as possible with the maximum input output moment ratio of device get big one this.Can make the better of acceleration performance change like this, desirable a little bit smaller of the reduction speed ratio of back axle simultaneously, can make like this motor the 70%-80% of output maximum (top) speed in addition when lower automobile be normally to have run at high speed, only just can reach maximum value to the motor output speed in hypervelocity, with the raising fuel economy, and make output power enough.

Four, the working efficiency of CVT (continuously variable transmission)

Because of no gearshift procedure, is conspicuous and working efficiency is improved as CVT (continuously variable transmission).Because of it is to be combined by torque-converters and planet row, if ignore oil pump power consumption and bearing resistance etc.The total efficiency of this speed changer is mainly torque-converters efficient and planet row efficient is long-pending.By figure (six) as can be known torque-converters efficient increase with speed ratio and improve.Efficient is 1 maximum when speed ratio is 1.Planet row's transmission efficiency is then determined by following formula ${\mathrm{\η}}_z=1-\left|\frac{N_a-N_h}{(I_{\mathrm{ab}}^h-1)N_h|}\right|----\left(16\right)$ By (16) formula sun gear rotational speed N as can be known _aWith the planet carrier rotational speed N _hDifference more little, η _zBig more.Work as N _aEqual N _hThe time planet row in each member become as a whole when rotating, η with speed _zEqual 1.Pump impeller in the torque-converters and turbine also rotate with speed at this moment, the noenergy loss.Do not have between each gear among the planet row and relatively rotate therefore nothing engagement loss.In fact only bigger as vehicular transmission in frequent starting of automobile or grade resistance, the pump impeller when output speed is low in the torque-converters, each member differential just can occur and rotates among turbine and the planet row.Most of the time all is that big or speed ratio is to work in 1 the scope at speed ratio.

Five, the structure of CVT (continuously variable transmission)

Shown in figure (seven), be provided with lock-up clutch 1 at the torque-converters front end, turbine 2 connects with clutch driving disk 9 by the spline on the axle, then connected by moving plate with planet carrier 8, the moment of torsion of turbine 2 can reach planet carrier 8 and even gear ring 14 when clutch, planet wheel 7 rotates with planet carrier 8, but axial rotation again.Gear ring 14 also meshes with planet wheel 7 with planet wheel 7 engagements, sun gear 13.Sun wheel shaft connects with a gear in the oil pump 4 by spline, Pump wheel shaft connects with another gear in the oil pump 4 by spline, pay tooth and combine as a whole for two in the oil pump 4 by the axle of paying of being with keyway, cause the moment of torsion of pump impeller 3 to reach 13 of sun gear by oil pump gear thus, sun gear 13 feedback torque also can reach on the pump impeller 3 by oil pump gear.As oil pump fluid is delivered in torque-converters and the hydraulic control oil circuit again simultaneously.Sun gear 13, planet wheel 7, differential rotates but gear ring 14 can rotate also with speed, and 5 is brake cylinder, and 6 is clamping strap, and 9 is clutch plate, 10 is clutch plunger.Make that grade valve 15 is fixed on the transmission housing and respectively with oil pump, clutch, break, oil circuit is communicated with, so that solenoidoperated cluthes and break.Exocentric structure 12 drives the oil circuit of lock-up solenoid valve switch 11 with the control lock-up clutch, locking is engaged or separation.Drive clutch oil cylinder and planet carrier 8 are connected as a single entity, with its rotation.ATF fuel filter 16 is communicated with oil pump 4.Radiator is outside gearbox casing.

Claims (6)

1. Mainly form as figure (seven) stepless and automatic hydraulic planetary differential speed variator by fluid torque converter and single star-wheel.Pump impeller 3, turbine 2 and sun gear 13, planet wheel 7, planet carrier 8, gear ring 14 can rotate by differential, also can rotate with speed, continuously changes the output shaft rotating speed to reach, and increases the purpose of output torque.Selectro valve 15 respectively with oil pump 4, drive clutch 9, the oil cylinder oil circuit of break 6 is communicated with so that speed changer can be in " advancing ", " sky " or reverse gear state, the major technique feature of this CVT (continuously variable transmission) is:

   1, the transmission system of this speed changer is to be formed by fluid torque converter and the combination of single planet wheel.
2. 2, this speed changer is the power intake of speed changer with the pump impeller 3 of fluid torque converter always, is the clutch end of speed changer with gear ring 14.
3. 3, sun gear 13 is connected as a single entity by gear in the oil pump 4 and pump impeller 3 in this speed changer, and both always rotate with speed.
4. 4, turbine 2 engages planet carrier 8 by splined shaft and drive clutch 9 in this speed changer, rotates or separation with speed, with this road power cut.
5. 5, this speed changer is at forward gears, and when promptly input shaft and output shaft rotated in the same way, the planet carrier 8 among the planet row was the power input component all the time, and gear ring 14 is the power output member all the time, and sun gear 13 feeds back to the power that obtains the input end of speed changer.
6. 6, the output shaft rotating speed of this speed changer is continuous variation, and the ratio of input output moment is

   

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