DE3226823A1 - Infinitely variable control mechanism with a large control range, in particular for vehicle drives - Google Patents

Abstract

Published without abstract.

Description

Stepless variable speed gearbox with a large control range, especially for Vehicle Drives Description: The invention relates to a continuously variable variable speed transmission with a large control range, especially for vehicle drives with stepless and continuous Possibility of regulating the gearbox output speed from that for maximum forward travel speed required, up to the output speed equal to zero, i.e. vehicle standstill, alternatively up to the negative gear output speed required for the maximum reverse speed.

Optimal vehicle transmissions largely meet the following requirements: A) So that the engine is largely relieved of speed control tasks and can therefore always work at the operating point at which the required performance is provided with the best possible efficiency, the transmission must have a large control range exhibit. (For this, see the essay "Saving fuel through gearboxes?" By Dr. Ing. B. R. Höhn The transmission must also be in the lower power and speed range be infinitely variable, as this enables switching and motor, especially in city traffic loss of acceleration can be avoided.

B) The mean weighted according to the frequency of driving conditions and level of performance The overall efficiency of the transmission should be as high as possible.

C) The transmission must be automatable by means of a corresponding control be, D) The power related to the weight of the gear unit should be large.

E) The on the taking into account the gear efficiency performance related to the gear unit price should be high.

F) Starting up on a hill as well as soft starting for winter operation must be problem-free.

Variable speed gearbox G) Optimal braking with the motor, see B. at pass departures has to be possible.

H) Braking the vehicle to a standstill only by means of the Powertrain is desirable.

Various mechanical, continuously variable transmissions are known Constructions, which control ratios are larger only with relatively small powers than about 1: 7. (See also the article "Infinitely variable gears, properties and application part 2 in Ingenieur-digest, issue 10, Oct. 75, pages 71 - 76).

In the essay "Uniform cash calculation of planetary gears" No. 15 - 1976, pages 145 - 149, an actuating coupling gear is described on pages 148 and 149, which the output speeds of two parallel, driven by a common motor Gear stages coupled by a planetary gear. The directions of rotation of the two Gear stages are here in the same direction, so that with this gear the stepless Gearbox is relieved at the expense of the entire bearing area. From the automotive industry manual transmissions with friction clutches are known, which today often have five forward ratios are equipped to save energy, Also known are: automatic transmissions, which consists of a manual transmission with mostly three forward ratios and a torque converter as well as an associated control system. In addition, there is an automatic transmission with wide V-belt - Automobilwerke DAF - known, but only about one Control range corresponding to that of a normal gearbox is achieved. This Automatic transmission is equipped with a centrifugal clutch, which is a Engine speed above idle speed engine and transmission connects and at one Motor speed between the above and the teaching run-up speed of the motor and gearbox separates from each other again.

Then there are the gearbox designs described in the following technical articles known: "Saving fuel through gearboxes?" A systematic comparison of different Types of construction; by Dr. Ing.B.-R, Höhn VDI, Ingolstadt, Variable speed gear published in "Info 82" annual report of the VDI-Gesellschaft development and construction.

"System analysis and comparison of continuously variable transmission concepts for different Applications in motor vehicles by U.Rohs, H.J.Bartsch, H.D.Schneider No. 80.2.3.1, VDI-Gesellschaft Fahrzeugtehnik.

"Electronic control for fuel-efficient engine-transmission management in the research car UNI-CAR "by J.Helling and E.Stall, VDI reports 418.

"Powershiftable passenger cars - automatic transmissions for front-wheel drive" by H.-J. Roof, VDI reports 418.

None of the known transmissions are those listed under A) and B) Demands - namely, running the engine on the best speed torque curve Efficiency and good transmission efficiency - fulfilled in an optimal way.

With automatic gearboxes, clutch and engine acceleration losses occur on, the engine speed torque curve is only approximated to the optimal one; transmission with hydrodynamic torque converters show mainly in the lower speed range insufficient efficiency; all transmissions previously used in automotive engineering have an insufficient control range. In addition, none of the brake the vehicle optimally, especially not to a standstill, stopping and starting again on a hill is problematic with some transmissions.

The invention is based on the object through a novel combination known gear elements as well as through the use of one to be created at the same time suitable, sufficiently powerful and low-loss transmission element of a vehicle transmission to create, which a) without an additional switching stage at an engine speed as possible steady and gradual near idle speed Control drives loosely adjustable Gearbox output speeds from zero to the maximum forward travel speed of the vehicle corresponding transmission output speed allows, with the reverse drive is achieved by a reversing gear connected downstream or upstream, b) alternatively without Additional reversing gear, continuously and continuously adjustable gear output speeds between the maximum reverse speed at a defined engine speed as well as the maximum forward speed at an engine speed if possible Allows corresponding transmission output speeds close to the idle speed.

c) is automatically controlled with an appropriate control system, that the motor almost always on the speed-torque curve of the best efficiency is operated.

d) Avoids switching losses.

e) enables problem-free starting even on the mountain.

f) with the appropriate control, continuous and stepless start-up with adjustable maximum torque (winter operation).

g) optimal braking, e.g. when driving down passes and h) braking the This task is made possible by the vehicle with the engine running until it comes to a standstill solved according to the invention in that to transfer the power from the engine (1), see Fig. 1, at least two working in parallel to the gearbox output shaft (7) Gear stages (2) and (3) are used, the output shafts (5) and (6) at least one that corresponds to the direction of rotation of the motor and at least one, due to a step for reversing the direction of rotation (4) with the direction of rotation of the motor opposite Direction of rotation act on an epicyclic gear (8), by which this Output shafts (5) and (6) coupled to the output shaft (7) of the overall transmission are. At least one of the gear stages (2) or (3) is a mechanical belt transmission with infinitely variable translation. The translations of the epicyclic gear (8), the gear stages (2) and (3) and the direction of rotation reversing stage (4) are SO determined, that at any notor speed by setting the translations of the used Control gear to achieve the maximum overall gear ratio iGmax = nMotor / n7 necessary limit values the gearbox output speed n7 = 0 is reached In addition, the gear ratios of the differential drive are designed accordingly and / or the reversing gear (see Fig. 1) the overall ratio of the drive train determined so that at an engine speed as close as possible to idling speed, but at least at a lower than the maximum emergency speed and with minimum gear ratio iGmin = nMotor / n7 still the maximum vehicle speed is achieved. A reversing gear (see Fig. 1) is required for reversing.

The mode of action of this gear stage combination is to be explained with the epicyclic gearbox according to Fig. 1 based on the gearbox diagram, Fig. 3 and the speed diagram, Fig. 4 of the epicyclic gear (8): If one carries the peripheral speeds of the gear rims z6; z5 and the planetary gears - center at the respective distance r6; r5 and r7 from the The epicyclic gearbox is horizontal, the tanß = v / r is proportional to the speed n.

If the circumferential speeds = v6min - v6max that are possible due to the controllability of gear stage (2) are plotted on radius r6 and the speed v5 (negative due to the corresponding design of gear stage (3 + 4)) results on radius r5, the result is the speed of the planetary gear center and so that the output shaft v7 at the radius r7, as can easily be seen from Figure #, to Description of continuously variable control gear If, as drawn to scale in Fig. 4, v5 = - v6min is selected by means of a corresponding gear design, then With this arrangement, it is possible to expand the control range of a controllable gear stage (2) according to the definition for the control range tP = nmax / nmin to = n7max / n7min = n7max / 0 = #.

The disadvantage of the solution according to Fig. 1 is that, especially in the case of unfavorable Efficiency of the individual gear stages (2), (3) and (4) as well as the epicyclic gear (8) the idle power circulating in the gearbox worsens the gearbox efficiency. This applies above all to large gear ratios i different from what is described above According to the invention, the object is also achieved in that the translations the epicyclic gear (8) of the gear stages (2) and (3) and the reverse stage (4) are determined so that by setting the gear ratios of the control gear used to the limit values necessary for the minimum output speed n7min with a specified Motor speed the gear speed required for maximum reverse speed n7 is reached. A direction of rotation reversal step for reverse travel is not then needed.

An advantageous solution is obtained if for both gear stages (2) and (3) belt transmissions with variable ratio can be used, see Fig. 2. Here, for small overall ratios i6, i.e. relatively high gear output speeds, set the gear stage (3) so that the wide V-belt is on the pulley (31) on the smallest possible, on the pulley (32) on the largest possible Diameter runs, while the gearbox output speeds through the gear stage (2) can be controlled. For small and negative (reverse travel) Gearbox output speeds, on the other hand, the gear stage (2) is set so that its Reduction corresponds to the maximum possible value, while the gearbox output speeds can be regulated by means of the adjustable gear stage (3). This achieves that in the most frequently required operating states of the transmission, the empty in Gear circulating power small, so the efficiency optimal and the wide V-belts are only slightly burdened by this service. This solution can be used for both Gearbox output speeds from zero to the maximum required positive, whereby a reversing gear is required for reversing (see Fig. 1), as well for gearbox output speeds of the maximum negative required for reverse travel can be designed up to the maximum positive required for forward travel.

The mode of operation of this gear stage combination (see Fig. 2) with the epicyclic gear (8) is to be explained using the gear diagram (Fig.) And the speed diagram (Fig. 6) of the epicyclic gear (8): Is carried out as for Figs. 3 and 4 described, the limit values of the variable speeds v6 and V5 due to the controllability of the gear stages (2) and (3) in the speed plan, it can be seen that Since v5 is always a negative value, v7min becomes negative at v6 (Iv5 is also negative. By selecting the values of v5min and v6min accordingly, v7min can be determined in such a way that the transmission output speed n7 required for the maximum reverse speed is reached at a specified engine speed In the gearbox output speed range corresponding to V7max to V7m, the gearbox description of the stun-less variable speed gearbox stage (3) is set to v5max (smallest absolute amount!), then the idle power circulating in the gearbox is small in this most frequently required gear range, which means that the individual gearbox stages are particularly efficient ( 2), (3) and (4) as well as the epicyclic gear (8) the overall gear efficiency is only slightly deteriorated.

Furthermore, the object is achieved according to the invention in that the adjustment the translation of the variable speed gearbox by motor, e.g.

is carried out by an electric motor and that the gearbox and the motor by means of a suitable control automatically and controlled so that - the drive motor (1) within the scope of the possibilities of the gear unit, regardless of the gear unit output speed on the, taking into account the lowest possible fuel consumption, one sufficient engine service life and largely residue-free combustion Speed-torque characteristic is operated, - The output speed in the absence of a manual drive command always controlled to zero and by a loop between Output shaft (7) and the adjustment drive for the gear stage (3) (see Fig. 2), by which the translation of the gear stage (3) is regulated via the adjustment drive is that the output speed is kept at the value zero. This achieves that the vehicle even on the steepest mountain without the aid of a parking brake holds securely. Since the gearbox is self-locking in this position, viewed from the load the engine can be switched off after stopping on the hill, the vehicle will don't roll away.

A possible electromechanical coupling is shown in Fig. 2: The V-belt pulley running loosely on the output shaft (7) is activated at an output speed close to zero by the electro-magnet (13) by means of the coupling (14) with this output shaft connected and adjusts the adjustment drive if the direction of action is selected correctly for the gear stage (3) until the output speed is the same Is zero. However, this coupling can also be done in other ways, e.g. purely electrically, by means of a tachometer generator or digital angular position signals on the drive shaft (7) and adjusting the translation by means of a servomotor (11).

- when reducing the size of the manual drive command (take off the gas) depending on the degree of this reduction, the drive power is reduced, equal to zero or negative (braking power) becomes, while suddenly reducing the size of the manual Driving command to zero the vehicle through appropriate control of the gearbox and Motor is braked.

- a manually adjustable maximum drive force not or only is exceeded when the "accelerator" is fully depressed (important for winter operation).

A centrifugal clutch subject to hysteresis, which occurs when a The engine speed is well above the idling speed and connects the engine and transmission disengaged again at an engine speed well below idling speed starting the engine can be made easier.

The advantages achieved with the invention are in particular: that - the drive motor (1) is automatic, i.e. independent of the driving behavior of the operator, is operated on the speed-torque characteristic curve, on which, taking into account a sufficient engine service life and residue-free combustion Required performance is provided with the best possible degree of efficiency, thereby reducing the fuel consumption consumption is reduced.

- Switching losses are avoided and therefore fuel is also saved will.

- thanks to better acceleration with the same engine power description Stunning variable speed gear values and reaching the maximum speed with maximum engine power (this is not the rule with conventional gearboxes) for the same level of performance a weaker motor is sufficient, which saves manufacturing costs and, since a weaker one Engine performs the same with better efficiency, fuel consumption is lowered.

when accelerating at low speeds, e.g.

in city traffic, the engine runs at a relatively low speed, which means that the Engine noise is significantly reduced.

easy stopping and starting is achieved even on the mountain.

by the possibility that the vehicle is only due to the braking power to be able to brake the engine to a standstill and thereby that the vehicle at Removing a manual drive command stops automatically, which is essential to safety increased and the brake wear is reduced that the operating effort for the Vehicle is reduced, whereby the driver can largely devote himself to the traffic.

L e r s e i t e

Claims (10)

Stepless variable speed gearbox with a large control range, especially for Vehicle drives Patent claims: 1.) Infinitely variable control gear with a large control range in particular special for vehicle drives, characterized by the combination of at least two working in parallel to transfer power from the engine (1) gear stages (2) and (3) used for the gear output shaft (7) with an epicyclic gear (8) and a direction of rotation reversing stage (4), with at least one of the gear stages (2) or (3) coincides with the direction of rotation of the motor and at least one, conditionally by reversing the direction of rotation (4), the direction of rotation of the motor is opposite Direction of rotation acts on the epicyclic gear (8) through which the output shafts (5) and (6) of the gear stage (2) and (3) with the output shaft (7) of the entire gear unit are coupled. The control gear is further characterized in that at least one of the gear stages (2) or (3) a belt gear with continuously variable Translation is and that the translations of the gear stages (2) and (3) and the Direction of rotation reversing stage (4) and the epicyclic gear (8) are set so that when setting the translation of the control gear used on the for Achievement of the lowest possible gear output speed n7 necessary limit ratio at least almost the transmission output speed n = 0, i.e. the vehicle has come to a standstill will. 2,) Infinitely variable variable speed gearbox with a large control range in particular for vehicle drives, characterized by the combination of at least two in parallel working, for power transmission from the motor (2) to the gearbox output shaft (7) used gear stages (2) and (3) with an epicyclic gear (8) and a reversing stage (4), where at least one of the gear stages (2) or (3) corresponds to the direction of rotation of the motor matching and at least one, due to the direction of rotation reversal stage (4) with the engine direction of rotation opposite direction of rotation the epicyclic gear (8) acts through which the output shafts (5) and (6) of the gear stage (2) and (3) are coupled to the output shaft (7) of the overall drive. The variable speed transmission is further characterized in that at least one of the gear stages (2) or (3) is a belt drive with continuously variable translation and that the Gear ratios of gear stages (2) and (3) as well as the direction of rotation reversal stage (4) and the epicyclic gear (8) are set so that when the translation is set the variable speed gear used to achieve the lowest possible gear output speed n7 necessary limit ratio at a specified engine speed to achieve the the highest possible return speed necessary gearbox output speed n7 is achieved. 3.) Continuously variable transmission according to claim 1 or 2, characterized by combining this transmission with a motor vehicle engine. 4.) continuously variable transmission according to claim 1 or 2, accordingly Figure 2, characterized in that two gear stages (2) and (3) are available are and that both gear stages are loop gear with adjustable translation are. 5.) Continuously variable transmission according to claim 1 or 2 and 4, accordingly Figure 2, characterized in that the regulation of the overall transmission ratio iG = nmotor / n7 for small values of i @ so large values for n7 by adjusting the translation of the gear stage (2) driving in the positive direction takes place, while the gear stage (3) driving in the negative direction is set so that the idle power becomes a minimum. The variable speed gearbox is also marked in that the translation of the gear stage (2) with large and negative translations iG, that is, low or negative output speeds n7 are set to the limit value is, at which the output speed n6 is a minimum, while the total transmission output speeds n7 can be controlled by means of gear stage (3). 6.) Continuously variable transmission according to claim 1 or 2, characterized in that that the translations of the epicyclic gear (8), the direction of rotation reversing stage (4) as well as the gear stages (2) and (3) and the translation of the differential drive are determined so that at an engine speed as close as possible to idling speed, but at least at an engine speed that is significantly lower than the maximum the output speed n7 required at maximum forward speed is reached will. 7.) Continuously variable transmission according to claim 1 or 2, characterized in that that the control of the gear ratio takes place so that the gear drive speed always at the gearbox output speed corresponding to the vehicle speed corresponds to the engine speed at which the engine the respectively required Performance taking into account a sufficient engine life and residue-free Provides combustion with the best possible degree of efficiency. 8.) Continuously variable transmission according to claim 1 or 2, characterized in that that a control is available, which the transmission after canceling the manual Drive command controls so that the transmission output speed and thus the vehicle speed becomes at least almost equal to ei ch zero. 9,) continuously variable transmission according to claim 1 or 2, characterized in that that a connectable coupling (12) of the output shaft (7) with the adjustment drive, which acts on the gear stage (2) or (3) with which the gear output speed n7 = zero is reached, is present, due to the in the switched-on state of the Adjusting drive is adjusted so that the gearbox output speed n7 = zero is held. 10.) Continuously variable transmission according to claim 1 or 2, characterized in that that there is a control by which when reducing the size of the manual Drive command (take off the throttle), depending on the degree of reduction, the drive power is reduced, equals zero or negative (braking power). Control gear 11.) Continuously variable control gear according to claim 1 or 2, characterized in that a wide V-belt, such as in the patent application for wide V-belts, applicant: Robert Schönfeld, applicant no. 1510800, described, is used