DE4032851C1 - Power transmission system for heavy duty motor vehicle - forms integrated mechano-pneumatic assembly with stepless speed-torque control including braking and reverse motion - Google Patents

Abstract

The power transmission system has an i.c. engine driving shaft (10) and shaft coupled (11,12) air compressor/drive units (V1,V2,V3) which together with stepped planetary gearing (13 to 18) and suitable control valve circuitry form an integrated mechano-pneumatic assembly with stepless speed/torque control including braking and reverse motion. The output torque of the system consists of a direct mechanical component and a variable component resulting from controlled pressure differences operating on unit (V3) as a motor combined in planetary transmission at output shaft (19). Torque amplification and temp. control of air expansion/compression is inherent in system. USE/ADVANTAGE - Public transport systems. Is integrated unit using fewer components than alternative assemblies. Provides retardation, idling and torque amplification without need for separate elements e.g. mechanical couplings or braking systems. Can provide smooth control of speed and torque including standstill and reverse with i.c. engine running at constant speed.

Description

The invention relates to a drive arrangement, in particular for motor vehicles, according to the preamble of claim 1. Such arrangements, with the basic idea, air or Air pressure differences as a means of power transmission too use and engine, loader and gearbox integrate that they complement each other in their effect known.

A drive arrangement is proposed in DE-PS 36 11 171, the - through expansion of an air volume and from it resulting heat removal - kept thermally stable and is therefore only sufficiently resilient. A torque Reinforcement can build on it, e.g. B. by means of switched planetary gear sets can be reached, possibly with Freewheel elements combined; d. H. each with a relative high proportion of mechanical components.

In DE-PS 37 20 236 an arrangement is also specified which already has a continuously adjustable torque boost, with the aid of rotatably arranged compressors. However, rotatable compressors also produce large ones rotating masses and a corresponding load on the load bearing; and independence would be even more constructional effort to maintain the compressed or to operate expanded air volumes to achieve the desired Effect compared to the stationary gear housing without restriction to achieve kung.

Both versions also require a separate reversal gearbox and set conventional braking devices for the Output shaft ahead.

The invention is based on the object, a Drive arrangement according to the preamble of claim 1 design in which all drive functions with pneumatic or pneumomechanical means and with one if possible low proportion of mechanical components are realized.  

The task includes a continuous over Settlement change from idle to at least translation 1: 1 and a continuously adjustable torque amplification also an integrated over the entire reduction range Reverse gear and an active (operated with the motor power bene) Delay device for the output shaft, adjust bar with the help of valves, preferably a throttle valves, and without mechanical clutches, mechanical brakes elements or freewheel components.

According to the task with the in the characterizing nenden features of claim 1 resolved means the thermal controllability of the system through use of positive and negative pressure according to DE-PS 36 11 171 always ahead set.

To solve the problem, the arrangement according to the Invention - like DE-PS 36 11 171 - the approach, the driving force branch of the engine into two components: one purely mechanical and at least one pneumomechanical comm component. Branch and merge of the transmission paths happen as there essentially with the help of a circulation gear transmission (with graduated planet gears). The core of the invention is a stepless adjustable torque amplification of the output shaft to pneu matic way, with the compressor casing at rest. The stepless torque change reciprocally to a speed The output shaft is changed by combining two aerostatic transmission paths reached.

Here, a compressor motor V 3 arranged on the output side is coupled to two compressors V 1 and V 2 arranged on the drive side via air chambers which act aerostatically on V 3 .

V 1 and V 2 generate or transmit different sized pressures or different sized moments, one of which, for example that of V 2 , is greater than the input torque of the transmission.

The higher pressures (overpressure or underpressure) which the compressor V 2 can generate result from a corresponding reduction with respect to the crankshaft of the engine and / or from a relatively small delivery space with respect to the compressor V 3 .

The proportion of the lower pressure compressor V 1 , which acts on the compressor motor V 3 parallel to V 2 , can be changed with the help of throttle valves - depending on the load. Intermediate check valves prevent a back effect of the jointly generated positive or negative pressure on the weaker compressor V 1 .

With a suitable coupling of the compressor group with the links a planetary gear transmission can also be a pneumatically activated deceleration phase of the output shaft switch that without further mechanical components and without (fluidically less favorable) directional valves and which continuously with greater throttling of the associated valves goes into reverse.

A series connection of the compressor V 1 and V 2 arranged on the drive side, in which, for example, V 1 acts as a pre-compressor for V 2 - and the delivery chamber of V 2 is divided into an expander part V 2.1 and a compressor part V 2.2 - increases the efficiency of the System and reduces the compression or expansion slip between the input and output speeds in the reduction range that occurs during aerostatic power transmission. In the gear ratio range 1: 1 and above, this speed difference, depending on the type of coupling with the planetary gear set, is completely and continuously compensated for by the interaction of the compressors V 1 and V 2 with the compressor motor V 3 .

Advantages of the invention compared to the known designs are especially

• - A simple, homogeneous structure of the system at maximum constructive freedom,
• - relatively few rotating parts, low friction losses and light weight,  
• -soft transitions between all drive phases, including reversal of direction,
• - an integrated retarder to be kept thermally neutral,
• - A simple control of all drive functions under Load.

In contrast to the known continuously variable transmissions, the working with frictional power transmission is a gradual process loose aerostatic transmission according to the invention also for suitable for high loads; and unlike automatic Driven with the hydrodynamic Föttinger converter, with permanent, undefined slip, high manufacturing costs and high fuel consumption, can be a drive assembly with a continuously variable aerostatic transmission according to the Er economical for engines with a smaller displacement be used.

This allows manufacturing costs, fuel consumption and

• - with the consumption also the pollutant emission
• - lower in a much wider area.

Regardless, the need for automatic, ins special stepless, gears rise everywhere there, where the traffic density increases, to the extent in which the vehicle speed is less by individual or technical requirements, but mainly through the column or determined by administrative intervention becomes.

The invention is shown in the accompanying sketches. The solution principle and the mode of operation of two preferred embodiments of the invention are explained in more detail below with reference to FIGS. 1-6, namely:

Fig. 1
- The schematic transmission plan for a version A (with a collective transmission) and the connections to the compressors V 1 , V 2 , V 3 ,

• - Drive: from the crankshaft 10
• - output: to shaft 19 ,

Fig. 2
- The pneumatic circuit for a version A with the compressors V 1 , V 2 , V 3 and the mechanical connections to the gear members in Fig. 1,

• - Inlet: from outside ( 20 )
• - outlet: to the engine ( 29 ),

Fig. 3
- The (tabularly staggered) diagram of the valve positions per drive phase for an embodiment A according to FIGS. 1 and 2 for the throttle valves D 1 -D 8 , based on the angular velocity w of the drive shaft 10 and the output shaft 19 ,

Fig. 4
- The schematic transmission plan for a version B (with a transfer case) and the connections to the compressors V 1 , V 2 , V 3 ,

• - Drive: from crankshaft 40
• - Output: to shaft 49 ,

Fig. 5
the pneumatic circuit for a version B with the compressors V 1 , V 2 , V 3 and the mechanical connections to the gear elements in FIG. 4,

• - Inlet: from outside ( 50 )
• - outlet: to the engine ( 59 ),

Fig. 6
- The (tabularly staggered) diagram of the valve positions per drive phase for an embodiment B according to FIGS. 4 and 5 for the throttle valves D 1 -D 8 , based on the angular velocity w of the drive shaft 40 and the output shaft 49 .

An embodiment A, shown schematically in Figs. 1-3, uses an epicyclic gear, which is connected as a collective gear.

In this embodiment, the driving force of the engine is guided from the crankshaft 10 to the central gear 13 and from there to the stepped planet gears ( 17 , 16 ) of the epicyclic gear. The load on the output shaft 19 , on the other hand, causes an evasive movement of the planet gears, as a result of which the compressor V 1 is driven by the hollow shaft 11 via the central wheel 14 .

When the vehicle is started, the compressor V 3 also initially turns backwards. The valves D 5 , D 6 are then still open and act as backflow valves. With the throttling of the valves D 5 , D 6 , the return flow through the compressor V 3 is continuously reduced until the pressure effect of the compressor V 2, which is driven directly by the crankshaft, prevails and the rotation or the flow rate of V 3 forward is directed. The flow rate of V 1 is still without influence on the power transmission at the start of the starting process. When throttling the valves D 1 , D 2 are now (via the chamber K 1 , K 2 ) to transmit additional pressure differences to the compressor motor V 3 , which - in the manner described in DE-PS 36 11 171 - in reaction forces or be converted into a torque.

In the embodiment A shown, this pneumomechanically generated torque is transmitted from a hollow shaft 12 to the internally toothed wheel 15 and then to the planet gears ( 16 , 17 ). The mechanical component via the wheel 13 and the pneumomechanical component via the planet gears ( 16 , 17 ) result in the resulting moment on the planet web 18 and thus on the output shaft 19 .

With the help of the throttle valves D 1 , D 2 , the pressure and delivery quantities of V 1 can be changed continuously and - even with the engine speed kept constant - adapted to the load or the specification of a specific vehicle speed. Check valves S 1 , S 2 , used individually or in sets, automatically prevent an undesired reaction of the pressure or negative pressure generated jointly by the chambers K 4 , K 3 to V 1 .

If the valves D 1 and D 2 are closed, an air flow under pressure change circulates primarily between the chambers K 1 -K 2 -K 4 -K 3 -K 1 and transfers the associated drive component to the planet gears ( 16 , 17 ). A secondary flow continues over the connection points 21 , 22 . The aerostatic pressure or power transmission does not result in a loss of torque, but a speed difference due to the compression or expansion slip between the compressor V 1 on the one hand and the compressor motor V 3 on the other. By throttling the valves D 7 , D 8 , angeord net according to FIG. 2, a further flow rate via V 2 is necessarily directed (or withdrawn from this) to the circulating main flow, which completely compensates for this speed difference, if necessary, even more (to an over drive phase): The additional air volume is sucked in via the shut-off valve S 4 from the outside ( 20 ) and released to the engine ( 29 ) via S 3 . During operation, a retarder function (to be kept thermally neutral) can be activated in any situation: by throttling the valves D 3 , D 4 , namely - with a continuous transition - a delay in the output shaft

up to the reverse run

y = w (19) <0,

with the angular velocity w of the output shaft 19 .

Accordingly, z. B. control a safe stand of the vehicle on a slope with the engine running by throttling D 3 , D 4 (down) or D 5 , D 6 (up) in the simplest way (see FIG. 3).

With additional (not shown) throttle valves between the chambers K 3 , K 4 and the compressor V 3 in the context of version A, a further amplification of the torque when starting is achievable.

Fig. 4-6 refer to a type B, with a transfer case.

The driving force of the engine is in this case guided by the crankshaft 40 onto the planetary web 43 and thus onto the stepped planet wheels ( 46 , 47 ). The load on the output shaft 49 - as in the embodiment A - causes an evasive movement of the planet gears, whereby the compressor V 1 is driven by the hollow shaft 41 .

When the vehicle is started, the compressor V 3 is initially carried along by the planet gear 43 via the ring gear 45 and the hollow shaft 42 . The throttle valves D 5 , D 6 are then still open and equalize the amount of air conveyed by the compressor V 2 as long as backflow valves. The speeds and delivery volumes are coordinated so that the pressure effect of the compressor V 2 only starts with a minimum throttling of the valves D 5 , D 6 .

With the throttling of the valves D 1 , D 2 - as in version A - additional pressure differences are then transferred to the compressor motor V 3 .

The resulting torque is finally Lich in design B transmitted from the hollow shaft 42 via the ring gear 45 to the ring gear 48 and from there to the output shaft 49 . The radius of the internally toothed wheel 45 is (with the purpose of the retarder function) somewhat smaller than the radius of the ring gear 48 . As a result, part of the pneumomechanical drive component is constantly transferred back to the shaft 40 via the planetary web 43 under load, so that there is no overall loss.

The valves D 1 , D 2 and S 1 , S 2 as well as D 3 , D 4 fulfill in principle the same function in version B as in version A; however, the gear ratio 1: 1 already results in B with partial throttling of the valves D 1 , D 2 .

In addition, in version B, the charge air quantity can be additionally increased by delimiting the conveying sections V 1 and V 3 by means of the throttle valves D 7 , D 8 , as shown in FIG. 5: The compressor V 3 then works (via the valves S 4 , S 3 ) as an additional charger, driven by the planet gears ( 46 , 47 ), with a secondary flow via the compressor chambers V 2.2 and V 2.1 and the connection points 52 , 51 .

Preferred applications for version A are Motor vehicles for high loads and with a relatively low Speed range, i.e. commercial vehicles, in particular Trucks and buses; for version B it is above all Passenger cars including high performance vehicles.

Further structural designs are within the scope of the invention possible, especially the type of epicyclic gear and regarding the type of coupling with the compressor group. In all cases, the use of positive and negative pressure for thermal stabilization of the system according to DE-PS 36 11 171 presuppose.

Claims (5)

1. Drive arrangement, in particular for motor vehicles, with an internal combustion engine, with a number of compressors of the displacer type, which are integrated into the power transmission via members of an epicyclic gearbox and thereby to cool the system (by expanding an air volume) and to charge the engine serve, furthermore with control and regulating elements and actuators for setting and maintaining predeterminable operating states, characterized in that

• a) that at least two compressors arranged on the drive side (V 1 ) and (V 2 ) generate pressure changes which - via pressure chambers (K 1 -K 4 ) - are transmitted aerostatically to at least one compressor (V 3 ) arranged on the output side, the compressors (V 1 ) and (V 2 ) are connected in parallel with respect to (V 3 ),
• b) that the compressors (V 1 ) and (V 2 ) specified in (a) transmit different large moments, one of which is greater than the input torque, and that actuators, preferably continuously variable throttle valves (D 1 , D 2 ) are provided, which can vary the relative proportions of the delivery quantities or the delivered moments of (V 1 ) and (V 2 ), while interposed check valves (S 1 , S 2 ) have a reaction of the jointly generated pressure or negative pressure on the prevent lower torque compressors,
• c) that further channels, throttle sections and valves are provided to the compressors specified in (a) and (b), which influence the drive of the vehicle pneumomechanically, in particular throttle valves (D 3 , D 4 ), which delay the output shaft and a Activate reversal of their direction of rotation.

2. Drive arrangement according to claim 1, characterized in that the delivery chamber of the higher-torque compressor arranged on the drive side, for example (V 2 ), - with a common drive unit - is divided into two separate rooms, namely in an expander part (V 2.1 ) and in a compressor part (V 2.2 ). 3. Drive arrangement according to claims 1 and 2, characterized in that the compressors arranged on the drive side (V 1 ) and (V 2 ) are pneumatically connected to one another, in such a way that part of the amount of air conveyed by the compressor (V 1 ) (before -compressed) to supply the compressor part (V 2.2 ) and / or that the compressor (V 1 ) on the other hand (in addition to further air supply from the outside) absorbs the delivery rate of the expander part (V 2.1 ). 4. Drive arrangement according to claims 1 to 3, characterized in that throttle valves D 5 , D 6 are provided as backflow or bypass valves to the compressors V 1 , V 2 , V 3 . 5. Drive arrangement according to claims 1 to 4, characterized in that the circulating flow between the compressors V 1 and V 2 or between V 1 and V 3 with throttle valves D 7 , D 8 is reduced.