DE19631236C2 - Gear unit and method for using a gear unit - Google Patents

Description

The invention relates to a transmission unit with a multi-range structure infinitely variable gears and with further gears.

Such gears are in EP 0 210 053, DE 41 13 386, GB 2 045 368 and GB 2 108 599. EP 0 210 053 shows a gear unit with a continuously variable transmission, such as conical pulley belt transmission, where for the shafts of the conical disk pairs on the input or output side with an input or Output shaft can be connected, the input shaft, such as drive shaft, and the output shaft, such as the output shaft, by means of the gear unit Clutches and other gear stages can be switched such that alternately a connection with the shafts of the conical disk pairs can be manufactured. This ensures that the usable translation range of the continuously variable transmission can be driven through several times.

A transmission unit with a multi-range structure is known from "VDI Reports 579 : Transmission in Vehicle Construction; Düsseldorf: 1986", pages 125 to 150.

It is a gear unit

• - With a conical pulley belt transmission as a continuously adjustable Gearbox whose transmission range can be driven through more than once and
• - With further gearboxes (2 spur gear stages and 1 superposition gear), where with a spur gear stage of the transmission unit for power transmission with means of the clutch K1 is switchable and
• - with a second clutch K2,
• - In a first working area V1 of the transmission, the first clutch K1 is closed and the second clutch K2 is opened and in a second working area V2 the first clutch K1 is open and the second clutch K2 is closed.
  The gear unit switches above a speed determined by the transmission ratios by changing the clutches K1 and K2 at the synchronous point between the work areas V1 and V2.

GB 2 045 368 and GB 2 108 599 each disclose a gear unit with an infinitely variable gear, such as a conical pulley belt gears or toroidal gears, the output of the continuously variable transmission especially with an input of a superposition gear, such as a summing gear, is connectable and a second input of the summing gear via a gear stage can be connected to the input of the continuously variable transmission, wherein the output of the summing gear is connected to the gear output shaft.  

These clutches can be used to switch on and off both the gear stage with a fixed gear ratio to one input of the summing gear and the summing gear alone. Common to the gearboxes of the above-mentioned EP-Offenlegungsschrift and the GB-Offenlegungsschriften is that the translation range of the continuously variable transmission can be driven through more than once and the range is switched over by means of clutches, the gearbox structure of the EP-Offenlegungsschrift being referred to as i ² gearbox is and the gear structure of the GB-Offenlegungsschriften known as geared-neutral structures with range switching.

The document JP 63-110045 A (abstract) discloses a transmission unit with Multi-area structure with a continuously variable transmission and others Gearboxes and two clutches, with one clutch being the transferable Torque to avoid switching shocks by means of a speed difference is controlled and there is a differential speed before and after switching.

With these gear structures, the transmission ranges are switched by means of couplings, which can be positive or frictional. The Difficulty with these gears arises from switching the transmission ranges with a fixed gear ratio, so that only in the ideal case can be switched by means of a dog clutch at the switchover point.  

From the document JP 4-331868 A (abstract) there is also a gear unit known in which a clutch between the engine and automatic transmission is provided with a variably adjustable, transferable torque, wherein their slip during a switching operation to avoid switching shock is controlled.

The object of the invention is to provide gear units with multi-range structures create which improve behavior in the area change as well have improved comfort.

It was also the task of creating a gear unit, which by means of a targeted strategy for control, e.g. B. with range switch a reduced number of components or a simplified structure has.

The object of the invention was furthermore to create a method which allows control to ensure comfortable behavior in areas to implement change processes.

This can be achieved by using gear units with gears, which the continuously variable transmission via at least two alternately Clutches that can be activated and deactivated with changeable transmissible torque are connectable, the switching process begins at differential speed and slides  he follows. With such gear units, the gear ratio range is infinitely variable adjustable gearbox can be used multiple times or driven through.

According to the invention, this can also be achieved by using the continuously adjustable transmission via at least two alternately switchable clutches the other gearboxes with adjustable, transferable torque are switchable, the switching process being initiated at differential speed and grinding takes place.

It can be particularly advantageous if, in the case of gear units with multib empire structure of the translation range of the continuously variable transmission can be driven through more than once by using at least two clutches when Errei Chen a certain gear ratio of the continuously adjustable Transmission can be switched on and off in the power flow of the transmission unit, in which there is also a reversal of the direction of actuation and that according to the actuation direction closed clutch before or after reaching the switch point begins to close.

The direction of actuation in the case of a continuously variable transmission, in particular in the case of a conical pulley belt transmission, indicates the direction of the control tion, e.g. B. the axial position of the conical washers, which is changed to to vary a gear ratio, d. H. with a conical disc set usually axially held a conical disc, the second conical disc is axially displaceable, the belt means of the continuously adjustable  Gearbox changes its running radius or contact area when relocated and thus a changed gear ratio is set. The actuation In this sense, direction means a change in the transmission ratio axially displaceable conical disc, with a change in the actuation direction a reversal of the axial direction of movement of the displacement of the cone disc is done.

Furthermore, in the case of a continuously variable transmission, it can advantageously be used a superposition gear, such as a summing gear, with two inputs and one Output in the torque flow can be switched on and off, whereby alternately one input with a subsequent gear stage up and down is switchable and the other input is continuously adjustable with the output part of the The gear unit is connected and the output part via a further coupling the superposition gear, such as summing gear, with the output part of the continuously variable transmission directly or indirectly via at least one fixed Ü Gear ratio is connectable and at least one clutch before or after Er range of the switching point begins to close.

Furthermore, it can be advantageous if, in the case of a gear unit with a multit empire structure a continuously variable transmission with a first and a second wave is arranged in the torque flow and the first and second waves as the input or output shaft of the continuously variable transmission alternately by means of at least two clutches, in particular by means of four clutches, switchable and the first and the second shaft by means of gear stages with a gear input  or transmission output shaft can be connected, a Umschaltvor gear from the first and second shaft as input or output shaft before or after reaching a switchover point at differential speed begins and continues fend takes place.

Furthermore, it can be particularly advantageous if at least one of the couplings gene a friction clutch, such as friction clutch and / or magnetic powder clutch, in particular all clutches Are clutches.

According to the inventive idea, it can be advantageous if one Control unit with sensors and / or other electronic units in signal connection is available and based on the operating point the translation of the infinitely variable ver adjustable transmission and the transmissible torque of at least one Coupling the gear unit with a multi-range structure.

In essence, it can be expedient if the control unit has a central one Computer unit has.

Furthermore, it can be advantageous if control means for actuation and control tion of the adjustable cylinder and / or pressure cylinder of the continuously adjustable Gearbox and at least one clutch are available, which hydraulic, mechanically or electromotively operated.  

It can also be expedient to design a gear unit in such a way that that a range change of the continuously variable transmission or the transmission unity by means of at least one controlled slip clutch if there is a difference speed occurs.

According to a further inventive idea, it can be advantageous if at a method for controlling or regulating a gear unit with multiple empire structure with a continuously variable transmission and other transmissions the translation range of the continuously variable transmission more than once is passable and at least two clutches when a be reached agreed gear ratio of the continuously variable transmission other re gear units in the power flow can be switched on and off, the, according to him following reversal of direction of actuation of the continuously variable transmission, closed The clutch begins to close before or after the switchover point is reached.

The switchover can be initiated before or after the switchover point is reached or be carried out. A case distinction is for the distinction from Train and push operation possible.

In train operation

• 1. When shifting into the transmission branch of the continuously variable transmission in the direction of low overall transmission ratio i _total (with increasing 1 / i _total ), the clutch beginning to be closed before the changeover point is reached.
• 2. When shifting in the direction of smaller 1 / i _total , the clutch starting to close after reaching the switchover point.

In overrun mode

• 1. When shifting towards increasing 1 / i _total , the clutch begins to close after reaching the switchover point and
• 2. When switching in the direction of smaller 1 / i _total , the clutch beginning to close before reaching the changeover point.

This case distinction can also be formulated in such a way that in the train area with a smaller reciprocal overall translation (with a smaller rotation numerical ratio ωA / ωE corresponding to the synchronous point at which the differences speed in both clutches is 0) the range change is initiated.

In the thrust area, a higher reciprocal overall ratio (with egg nem higher speed ratio) than the synchronization point of the range change initiated.

According to the method according to the invention, it can be advantageous if a loading Empire change of the continuously variable transmission or the gear unit  by means of at least one controlled slip clutch at differential speed is initiated or takes place.

The slip or the differential speed at which a shift or Um switching process takes place or is initiated, is preferably a value small ner 50 1 / min, a value in the range 20 1 / min to 2 1 / min is preferred.

The invention further relates to a method for changing the transmission paths of a multi-range transmission according to the preamble of claim 8 and a multi-range gearbox to carry out the method.

Particularly for their use in motor vehicles, multi-range transmissions known from the prior art are becoming increasingly important because of the consumption savings potential associated with their use. Examples of such multi-range gearboxes are in Lechner, G .; Nauheimer, H .: Fahrzeugantrieb, Springer-Verlag 1994 , in particular pages 144 to 146.

Theoretically, with such multi-range gearboxes, switching from one Transmission path to another at the differential speed 0 each Weil open clutch, d. H. at the synchronization point. Accordingly one has tries to get by with simple, form-fitting claw couplings men that are indented or disengaged at differential speed 0. The order Circuit was unsatisfactory in comfort, however, so you tried using one bevels on the side of the driving surfaces make the transitions cheaper  to design, which, however, only in a torque support direction Claw clutches can succeed.

There have also been attempts to control the switching processes in a satisfactory manner with frictional clutches and freewheels. In Oetting, H .; Heidemeyer, P .: Continuously variable transmissions for passenger cars, VDI reports 579 indicate that the controls of such clutches are extremely complex.

The invention is also based on the object of a method according to the O Generic term of claim 8 to create, which is structurally simple formation of the transmission and low control or regulation effort in Shift comfort satisfied. The invention is further based on the object Multi-range transmission for performing the method according to the invention to admit.

The part of the object of the invention relating to the method is marked with the characteristics len of claim 8 solved. Surprisingly, it has been found that perfect shifting comfort can be achieved if you counter the front prevailing doctrine that the multi-range transmission is not in its neutral point, d. H. at differential speed 0 of the respective open clutch, but switches outside the neutral point. In this way, the control effort decreases since the exact translation does not have to be recorded for which the difference speed is zero, but switching is possible over a range in which egg ne low differential speed is present. With usual friction clutches  can use these differential speeds when closing the clutch and essentially Liche opening of the other friction clutch can be smoothed. Because the differential speed is such that when changing the Ü transmission paths between input shaft and output shaft or thrust is supported by the clutch closing, happens changing the transmission path in an extremely convenient way without a drop in torque or a drop in train or thrust or even reversal. Backlash between gears or torsional elasticity have no influence.

The sub-claims 9 to 12 are advantageous embodiments of the he directed method according to the invention.

The method according to the invention can be used for largely all multi-range transmissions are used in which between the individual transmission paths is switched by means of friction clutches. The used stepless ver adjustable transmission can be a belt transmission, for example with a tapered Pulleys, a hydrostatic transmission or a multi-speed Ge be drives, the steps of which are smoothed by converters or friction clutches the. There is also extensive freedom for the further transmission path. It is crucial that the multi-range transmission has a synchronization point, in which the continuously variable transmission works with a ratio that leads to a dif limit speed of zero of the open clutch or clutches.  

Claims 13 and 14 are based on particularly advantageous embodiments Nes multi-range gear directed to implement the Invention according to the method is particularly well suited.

The invention will be explained with reference to FIGS. 1 to 13.

It shows:

Fig. 1 is a schematic representation of a transmission unit,

Fig. 2 is a schematic representation of another transmission unit,

Fig. 3 is a schematic diagram,

Fig. 4 is a functional diagram and

Fig. 5 is a schematic representation.

Fig. 6 is a schematic diagram ei nes multi-range transmission with two transmission paths,

FIGS. 7 and 8 sketches for explaining the changing of the transmission paths in the transmission shown in FIG. 6,

Fig. 9 shows a modified embodiment of a transmission with power branching,

Fig. 10 is a sketch for explaining the operation of the transmission shown in FIG. 9,

Fig. 11 shows a further embodiment of a transmission with two branches,

Fig. 12 is a sketch for explaining the operation of the transmission according to Fig. 11 and

Fig. 13 is a block diagram for explaining the control of the transmission of FIG. 9.

Fig. 1 shows a transmission unit, which is constructed on the principle of the geared-neutral transmission, with a transmission input shaft 2 and a Ge transmission output shaft 3rd The transmission input shaft 2 can be connected directly or via a torsional vibration damper, such as a dual mass flywheel, to the output shaft of an engine, such as an internal combustion engine. The transmission output shaft 3 is connected to an output shaft which acts via a differential on at least one drive axle, which is not shown in FIG. 1.

Furthermore, the transmission input shaft 2 can also be operatively connected to a starting element, wherein a multi-plate clutch, a friction clutch or a hydrodynamic torque converter can be provided.

The transmission unit 1 comprises a continuously variable transmission 1 a with a first cone pulley set 4 and a second cone pulley set 5 , wherein a looping means 6 binds the two cone pulley sets 4 and 5 in the torque flow, and the radial position or the radial arrangement of the belt means 6 , such as chain or push link belt, determines the translation of the continuously variable transmission. The conical disks 4 and 5 are composed of a conical disk 4 a, 5 a connected to the input shaft or an output shaft in a rotationally fixed manner, and an axially displaceable conical disk 4 b, 5 b, the displaceable conical disks 4 b, 5 b by means of the piston Cylinder units 7 , 8 are axially displaceable. The axial displacement of the cone discs 4 b, 5 b and the resulting change in gear ratio is controlled by means of pressurizing the piston-cylinder units 7 , 8 .

The output shaft of the continuously variable transmission 9 is in this exemplary embodiment with the sun gear 10 of a superposition gear, such as a sum mier gear, such as a planetary gear. Parallel to the continuously variable transmission, another transmission with a fixed transmission is connected in parallel, a gear wheel 12 being connectable to the input shaft 2 via a clutch 11 and the gear wheel 12 driving the planet carrier 13 of the summing gear mechanism via a transmission stage. The ring gear 14 of the planetary gear is connected to the output shaft 3 of the gear. Via a clutch 15 , the ring gear and the planet carrier can be connected to one another in a rotationally fixed manner, so that the planet carrier and ring gear rotate as a fixed block.

The multi-range transmission of FIG. 1 can generate an output speed of the output shaft 3 with the clutch 11 and the clutch 15 in the first operating range with the driven shaft 2 at a suitable ratio of the continuously variable transmission, which is zero, so that the ratio of the output speed to Drive speed is zero and by vari ation of the variator ratio of the continuously variable transmission, a vehicle can be started in the forward or in the reverse direction, the transmission having to be changed accordingly in one direction or another based on the "neutral ratio" of the continuously variable transmission ,

In a further gear ratio range of the gearbox, the clutch 11 is opened and the fixed gear ratio is decoupled from the one input 13 of the summing gearbox and the clutch 15 is closed, so that the shaft 9 is essentially rigidly coupled to the shaft 3 of the gearbox. Thus, in a second operating range, the transmission unit can be used as a purely continuously variable transmission.

One of the gear ranges described above is called the Geared Neutral range designated, because with driven input of the transmission, the output shaft with a speed of zero can be operated and a vehicle accordingly held at a standstill without clutch actuation while the drive motor is running can be, the translation control a starting or braking steered into the neutral range. The second operating area of the Mehrbe empire structure serves to translate the translation range of the continuously variable Use gearbox one more time to increase gear spread or egg to realize a cheaper dimensioning.

The Fig. 2 also shows a gear unit with multigrade structure with a continuously variable transmission is used. The transmission input shaft 50 can be connected by means of a gear stage and the clutches 51 and 52 to the shafts 53 and 54 , these shafts in turn being connectable to the clutches 55 and 56 via gear stages to the output shaft 57 .

The gear stages are represented by the input and output shaft gears 50 a, 57 a and the gears 51 a, 52 a, 55 a and 56 a engaging in these gears. This results in a transmission ratio between the input and output shafts 50 , 57 and the clutches 52 , 51 , 55 , 56 and the shafts 54 , 53 , which is fixed by the choice of gears and depending on the coupling actuated.

The operation of a transmission shown in Fig. 2 can be explained by the fact that the clutches 51 , 52 and 55 , 56 are mutually engaged or disengaged, so that each diametrically opposite hitchings are engaged according to this scheme and the others both clutches are disengaged. Starting with a closed clutch 52 and an open clutch 51 , the drive-side torque is transmitted from the drive shaft 50 via the clutch 52 to the variator 58 , the two cone disks 59 being connected to the cone disks 61 in the power flow via a belt means 60 . At the same time, the clutch 55 is opened and the clutch 56 is closed, so that a torque is transmitted from the shaft 53 via the conical disk and the belt means 60 to the conical disk pair 61 and from there via the shaft 54 and the clutch 56 to the output shaft 57 becomes.

In a second operating range, the clutches 52 and 56 are open and the clutches 51 and 55 are closed, so that the torque flow takes place from the drive shaft 50 via the clutch 51 to the conical disk pair 61 and from there via the belt means to the conical disk pair 59 and over the clutch 55 to the output shaft 57 . Because of this arrangement, the transmission ratio of the variator can be used several times by means of the transmission stages of the driven shafts 53 and 54 . The engagement of the clutches, which are preferably provided as frictional clutches, should take place at differential speed, so that a sliding shifting process takes place. This ensures a comfortable shifting process.

FIG. 3 shows a control unit 100 with various inputs 101 to 103 for connection with sensors. These sensors signal or detect the respective operating state of the system, such as a vehicle, such sensors characterizing, for example, the engine speed, the transmission input speed, the vehicle speed, the throttle valve position of the engine, the load lever position or other state variables. A sensor is also assigned to the gear selector lever 105 , which detects the gear or gear selected and forwards it via the signal line 106 to the input 104 of the control unit 100 .

The control unit 100 controls the transmission ratio of the continuously variable transmission 110 , such as a conical pulley belt transmission or a toroidal transmission, whereby a pressurization of the pressure cylinders, such as contact and adjusting cylinders, 113 and 114 is controlled, the translation being set with the axial displacement of at least one pulley of each pulley set becomes. Furthermore, the control unit 100 controls the clutches 111 to 112 , so that the engagement state or the torque that can be transmitted by these clutches is specifically varied and determined.

The clutches 111 to 112 are shown schematically and depending on the embodiment, a different number of clutches can be shown with the clutches 111 to 112 . In the embodiment of FIG. 1, two clutches 11 and 15 are shown, which are opened or closed in the range switch or are specifically controlled when crawling. In Fig. 2, four clutches 51 , 52 and 55 and 56 are provided, which are controlled, opened or closed at a range change.

When changing the range of gear units with multi-range structures, the engagement and disengagement strategies of the corresponding clutches can be carried out in the same way as when changing gears from stepped automatic machines. When changing speeds from automatic machines, speed jumps in the range 1 , 2 to 1 , 6 are usually carried out, which must be synchronized by means of clutches. The present invention is based on performing a range change in the above-mentioned gear units with multi-range structures in such a way that shifting takes place at differential speeds, ie is not shifted at the synchronous point and the differential speeds are very small, ie that the ratio of the speeds during the switching process to the speed before and after the switching process is in the range up to 1.1 and special up to 1.05 or up to 1.01. Each shift can take place without changing with a constant output torque curve, ie the range changes in the direction of larger or smaller ratios take place without interrupting the tractive force.

The differential speed at which the range change is started can change from the resolution of the speed signals and a dead time in the determination the speed signals and a lead value, which the dynamics of Systems considered as a function of time. Thus, in the event of a change in area sel the dynamics of the system in particular the behavior in the area of Activation dead time is taken into account so that actuation during a differential rotation number can be made.

This control method can be carried out both in the geared-neutral gearboxes mentioned in the changeover range and in the so-called i ² gearboxes when changing the range.

When changing ranges, it is important that the torque curve is high on the output side remains and the power loss at the coupling is not too great. This can be achieved if the change of division is just before or after Synchronization point is carried out. The output torque curve remains homogeneous, also taking into account the existing elasticities in the transmission structure if an optimal differential speed and torque are controlled.  

Fig. 4 shows the course of the speed ratio between the output speed of the gear unit to the _input speed of the gear unit as a function of the variator ratio n _var , wherein the variator _ratio can be changed in the range from n _varmin to n _varmax . In a first operating range, the transmission ratio ω output to ω drive with the maximum variator ratio is minimal, as shown in the transmission ratio Ω ₁ . As the variator ratio n _var decreases, the gear ratio increases up to the value Ω ₂ . The curve 200 represents this fact of the speed ratio as a function of the variator ratio. Before the minimal variator ratio, as an example for an i ² transmission according to FIG. 2, a change or changeover of the waves of the conical disk sets is started, so that for a speed ratio Ω ₂ again an increasing speed ratio with increasing variator ratio takes place.

The switchover can now ideally take place at the specified variator ratio Ω ₃ or, as in the transmission according to the invention, at differential speed, as represented by line 201 . The switchover point Ω ₂ thus occurs before the specified variator ratio Ω ₃ . Accordingly, the cal matic representation of FIG. 4 can be used not only on a so-called i ² transmission, but also on so-called geared neutral transmissions or other multi-range structure transmissions.

According to FIG. 5, in the drive train between a drive device 401 and to drive wheels 402 of a motor vehicle on a connected to the drive means 401 shaft 403, a torsional damper 404, a continuously controllable frictional clutch K1, here a lamellar or friction clutch, speed gear as a rotation and The primary side of a continuously variable transmission 405 , here a belt transmission, serving as a torque converter, is arranged as a torque converter. The secondary side of the transmission 405 drives the central wheel of a planetary gear 407 , here a planet gear, via a shaft 406 , the ring gear of which is connected to the drive wheels 402 via a shaft 408 , a spur gear 409 and a differential gear 410 . The web of epicyclic gear 407 is connected via a spur gear 411 to the output side of clutch K1. The epicyclic gear 407 can be bridged by means of a second continuously controllable slipping clutch K2, which is connected on the one hand to the spur gear 411 and the epicyclic gear of the epicyclic gear 407 and on the other hand to the ring gear of the epicyclic gear 407 . This arrangement makes it possible to use the continuously variable transmission 405 both for zero-control operation (geared-neutral operation) with clutch K1 closed and clutch K2 open in the driving ranges “forward”, “reverse” and “neutral” as well as with the clutch open K1 and closed clutch K2 to be used in normal operations.

With the drive device 401 , the setpoint generator 412 for a Regeleinrich device 413 is connected, which in turn is connected to the drive train.

The reference value generator 412, a desired on the output side of the torque M _a, which may have a fixed or time-varying value, according to the driver, for example in dependence on the accelerator pedal position, as a selection signal and the drive device 401 is supplied as a control signal. The specification of the desired output torque M _a as a function of time t is schematically represented by a functional unit 414 . Furthermore, the setpoint generator 412 receives from the drive device 401 signals measured therein which correspond to the input speed n _e and the input torque M _{e of} the drive train. In addition, the driver can use a selector lever (not shown) on the setpoint generator 412 to set a standing, parking or neutral range P (park) and N (neutral) as well as a reverse and a forward driving range. The setpoint generator 412 contains a memory in which previously empirically determined pairs of values of speed differences Δn between the input and output sides of the clutch K1 and clutch torques M _K1 , which are to be transmitted by the clutch K1, as a function of the respective variables M _a , n _e and M _e are assigned to one another and stored in such a way that their product Δn × M _{K1 is} always approximately zero, but not equal to zero. The memory for a desired output torque M _a , which has a low creep torque M _Kr with an amount B that is between zero and, for example, fifty Newton meters (Nm), contains a speed difference or slip speed Δn associated with this amount between the input and output sides of the clutch K1 in the amount of A, which is between zero and, for example, fifty revolutions per minute, in each case for the reverse driving range and the forward driving range, the slip speed having a negative value A in the reverse driving range and a positive value A in the forward driving range. For desired output torques M _a , which are greater than the creeping torque M _Kr , that is to say driving torques M _F , values C × M _a proportional to the desired torque M _a are stored for the forward or reverse driving range (with C = const.) , In the stationary, park or neutral ranges P, N, the moments M _Kr and M _F and the speed difference Δn are almost zero.

The setpoint generator 412 then supplies the control device 413 with a setpoint signal that corresponds to a speed difference Δn retrieved from the memory in accordance with the input signals M _a , n _e and M _e , and with a setpoint signal for the pressure p _K1 that is also retrieved from the memory of the setpoint generator 412 in accordance with its input signals M _a , n _e and M _e and determines the pressure with which the two clutch halves of the clutch K1 are pressed together in order to transmit the desired torque M _{K1 of} the clutch K1 adjust.

A speed sensor 415 measuring the speed n ₁ on the primary side of the belt converter 405 and a speed sensor 416 measuring the speed n ₂ on the secondary side of the belt converter 405 each lead the control device 413 to an actual value signal corresponding to the measured speeds n ₁ and n ₂ is compared in the control device 413 with the setpoint signal for the speed difference Δn. Depending on the comparison result, the wrap converter 405 is then supplied with a control signal for the pressure p ₁ on the primary side and a control signal for the pressure p ₂ on the secondary side of the wrap converter 405 . These control signals then adjust the primary and secondary pressure cylinders of the belt converter 405 by compressing the respective pair of disks, the position of the looping means and thus the transmission ratio i = n ₁ / n _{2 of} the loop converter 405 so that the respective input signals of the target value generator 412 assigned speed difference Δn at clutch K1 results. Likewise, a pressure sensor (not shown) on the clutch K1 measures the actual value p _{K1 of} the pressure with which the clutch halves of the clutch K1 are pressed together and feeds this actual value to the control device 413 . The control device 413 then compares the actual value with the pressure setpoint p _K1 supplied to it by the setpoint generator 412 and regulates a difference between the setpoint and actual value so that an actuating signal corresponding to the setpoint and the clutch is generated at the pressure signal output for the pressure p _{K1 of} the clutch K1 Squeeze K1 accordingly. With the clutch K2 open, the gear ratio i corresponds to a forward gear ratio i _vw with a positive setpoint of the speed difference Δn (see the diagram entered in the control device 413 ) and with a negative setpoint for the speed difference Δn to a reverse gear _ratio i _rw , on the other hand for the stationary, Park or neutral range at the setpoint zero for the speed difference Δn a speed ratio i _Q for the geared-neutral point at which the output speed n _a is zero.

This ensures that the losses in the clutch K1 are very small over the entire operating range, since the product Δn × M _K1 determining these losses is approximately zero over the entire operating range, ie very small but not equal to zero.

Since also a very low output torque B, corresponding to a creep mo ment, with a very low slip speed A and corresponding gear ratio ratio i for low output speed, can be ensured with previous ones Translation regulations swinging of the vehicle occurring at a standstill be avoided, since the moment in the drive train is then only from the moment of Coupling K1 depends.

Referring to FIG. 6, a range-change transmission to a driven by a motor, not shown input shaft e and an output shaft for driving a working machine or the egg ner, for example, a vehicle. At a first branch node 503 , the transmission path from the input wave e to the output wave a is divided into two paths. A first path contains a friction clutch K1, which is followed by a translation stage 505 , to which a differential gear 507 connects, the output of which is connected via a second branch node 509 to the output shaft a.

The second transmission path contains a continuously variable transmission, which is formed, for example, as a belt transmission with two disks of variable diameter. The output of the continuously variable transmission is connected via a node 511 to a support member of the differential gear 507 and via a second friction clutch K2 to the second branching node 509 .

The transmission ratio determined by the differential gear 507 is such that the output shaft a rotates at N times the speed of the shaft coming from the transmission stage 505 when the node 511 is stationary.

The structure of such a transmission is known per se. The synchronization point ent speaks the translation of the continuously variable transmission at which the Speed ratios are such that both clutches K1 and K2 are closed can be d. H. work without differential speed.

The function of the transmission according to FIG. 6 and the switching between the clutches K1 and K2 are explained with reference to FIGS. 7 and 8.

In FIG. 8, the abscissa represents the speed ratio ν _G = ω _a / ω _e of the entire transmission and the ordinate represents the speed ratio of _CVT ω = _Wa / ω _e of the step idler gear ν applied. Mean
ν _G the speed ratio of the entire transmission,
ν _CVT the speed ratio of the CVT transmission,
ω _a the speed of the output shaft a,
ω _{e is} the speed of the input shaft e and
ω _{Wa is} the speed of the output shaft of the continuously variable transmission.

In the range of low overall speed ratios, the clutch K1 is closed and the clutch K2 is opened, the relative speed Δω _K2 / ω _{e of} the clutch K2 being indicated in the lower left half of FIG. 7. This relative speed decreases with decreasing speed ratio of the continuously variable transmission and becomes zero at the speed ratio 0.45, the synchronization point of the transmission. At speed ratios ν _G above 0.45, the clutch K2 is closed and the clutch K1 is open, the relative speed on the clutch K1 being indicated in the lower right half of FIG. 7.

The gearbox according to FIG. 6 is switched as follows:
In the traction range (input shaft e drives output shaft a), when the ratio is reduced, ie when shifting up, the system switches over before the syn chron point is reached, ie before the differential number of clutch K2 decreases to 0. If the clutch K2 is closed in this state and the clutch K1 is opened, a positive output torque is set due to the differential speed in the clutch K2, which delays the drive motor (not shown) until the clutch K2 no longer slips. A positive drive torque (train) before and after changing the transmission paths of the transmission or its range switchover is homogeneously supplemented by a positive drive torque by delaying the motor masses affected by inertia during the change of range.

Conversely, in the thrust area, clutch K2 closes and opens NEN of the clutch K1 only after passing through the synchronization point, so that the now required acceleration of the engine masses supplements the thrust torque.

Fig. 8 shows the corresponding control strategy when increasing gear ratio (downshift). In the train area, the change from clutch K2 to clutch K1 only takes place when a positive differential speed has built up in clutch K1. In contrast to conventional automatic stepping machines, this permits a change of range, which in turn results in a positive output torque during the change of range due to the deceleration of the motor. In the thrust area, conversely, the changeover occurs before the synchronization point, so that there is also a constant output torque curve during the change of range.

With the described control strategy or the procedure for changing the Ü Transmission paths are with a simple structure of the multi-range transmission or whose couplings achieved an extremely comfortable range change.

Fig. 9 shows schematically an embodiment of a multi-range transmission known per se, which is particularly well suited for carrying out the described range change method. The continuously variable transmission is designed as a belt transmission with two conical pulleys S1 and S2, the effective diameter of which determines the transmission ratio or speed ratio of the continuously variable transmission. The differential gear 507 is designed as a planetary gear, the ring gear 513 is non-rotatably connected to the output shaft a, the planet gear 515 meshes with the gear ratio 505 and the sun gear 517 is non-rotatably connected to the output shaft of the continuously variable transmission. The first clutch K1 connects the input shaft e to the transmission stage; the second clutch K2 connects the planet gear carrier 515 to the ring gear 513 .

The function of the transmission according to FIG. 9 is explained with reference to FIG. 10. The total speed ratio ν _G is plotted on the abscissa as the quotient of the speed ω _{a of} the output shaft a and the speed ω _{e of} the input shaft e. The ordinate shows the speed ratio ν _{CVT of} the continuously variable transmission as the ratio of the diameters of the pulleys of the S ₁ / S ₂ .

In power-split operation, in which the transmission stage 505 and the differential gear 507 are effective in addition to the continuously variable transmission, the clutch K1 is closed and the clutch K2 is opened; in direct operation, in which clutch K2 is closed and clutch K1 is open, only the continuously variable transmission is effective.

The switching strategy between the clutches K1 and K2 is the same as explained with reference to the previous embodiment according to FIGS. 6 to 8.

As can be seen, the speed ratio of the transmission according to FIG. 9 can be changed into the negative, so that only with the aid of the continuously variable transmission it is possible to switch between forward and reverse rotation of the output shaft.

Fig. 11 shows a further embodiment of a known transmission suitable for the use of the method according to the invention. This is a so-called i ² transmission, in which the spread of the continuously variable transmission can be used both in one direction and in the other.

The input shaft E of the transmission shown in FIG. 11 is wetting stage via a first transla and a clutch K1 a pulley S1 connected to the continuously variable transmission and a third transmission stage and ei ne third clutch K3 to the second pulley S2. The first belt pulley S1 is connected to the output shaft a via a clutch K2 and a second transmission stage. Likewise, the second pulley S2 is connected to the output shaft a via a clutch K4 and a fourth gear ratio.

According to FIG. 12 _, the clutches K1 and K4 are closed in the work area with a smaller overall ratio ω _e / ω _a and in the area with a larger overall ratio the clutches K2 and K3. The individual gear ratios are selected in such a way that the gear ratios shown and, in the case of the gear ratio 502 of the continuously variable transmission, result in the synchronization point at which all clutches can be closed without differential speed. The same strategy as explained above applies to switching the clutches K1 and K4 to K2 and K3 and vice versa. Again, it is possible with the invention, by using simple friction clutches K1 to K4, to move comfortably from one area to the other without any freewheels or dog clutches.

The method according to the invention as well as those working under its use Multi-range gearboxes are suitable for a variety of applications in which it is used simple construction to a smooth switching between arrives on the transmission paths. These can be drives of all kinds at for example for lathes, centrifuges, machine tools, etc. Especially the method according to the invention and that using it are suitable Process working multi-range gearboxes for motor vehicles.

FIG. 13 shows such an application example using the transmission according to FIG. 9.

The output shaft of the transmission a is connected via an axle differential 519 to the driven wheels 521 of a vehicle.

The input shaft e is connected via a dual-mass flywheel 523 to an internal combustion engine 525 , which is driven by an accelerator pedal 527 .

The ring gear 13 works with a lockup clutch KL to stop the vehicle.

A programmable electronic control unit 529 are the input variables (dashed lines), the speed wa of the output shaft a, the torque M _{D of} the internal combustion engine, the speed N of the internal combustion engine 525 , which corresponds to the speed of the input shaft e, and the speed of the output shaft ω _{a of} the continuously variable transmission. From these values, the electronic control unit 529 calculates values for controlling the translation of the continuously variable transmission as well as controlling the clutch K1 and K2 according to the switching strategy described with reference to FIGS . 7 and 8 between the transmission paths according to a program stored in it of the transmission.

The control of the continuously variable transmission as well as the clutches K1 and K2 can advantageously, as known per se, electronically-hydraulically take place, the actuating forces being applied hydraulically and the The size of the forces is determined electrically / electronically. The hydraulic parts can can also be replaced by electric servomotors.

In the example shown, the electronic control unit 529 calculates from the input variables whether the transmission is in overrun or in pull operation, in order to thereby activate the corresponding shift program according to FIGS. 7 and 8. It goes without saying that a sensor can be provided in the drive train which directly determines whether there is a pulling or pushing operation. The respective differential speed at which the respective clutch is switched and / or the switching speed can depend on the magnitude of the pulling or pushing torque.

The control unit 529 can be combined with an electronic engine control unit, so that the entire drive train control is integrated in one unit.

A method for changing the transmission paths of a multi-range transmission bes with an input shaft (e), an output shaft (a) and two by means of we at least one friction clutch (K1, K2) switchable transmission paths between the input and output waves, which transmission paths a stu fenfen adjustable gear included, which is arranged such that the Diffe limit speed of the respective open clutch at a specific ratio of the continuously variable transmission is 0, is characterized in that the order circuit between the transmission paths at a differential speed of Closing clutch (K1 or K2) takes place, the differential speed such is that by closing the clutch there is a gap between the input shaft (e) and the tensile or thrust torque transmitted to the output shaft (a) is supported becomes.

Claims (14)

1. gear unit with a multi-range structure, in which a continuously variable transmission ( 58 ) with a first and a second shaft ( 53 , 54 ) is arranged in the torque flow, and the first and second shaft ( 53 , 54 ) alternately by means of at least two clutches ( 51 , 52 , 55 , 56 ) as the drive or drive shaft of the continuously variable transmission ( 58 ) via gear stages ( 50 a, 57 a) with a transmission input or transmission output shaft ( 50 , 57 ) can be connected, characterized in that a switchover of the first shaft ( 53 ) as the input or output shaft and the second shaft ( 54 ) as the input or output shaft of the continuously variable transmission ( 58 ) before or after reaching one of the clutches ( 51 , 52 , 55 , 56 ) provided switching point at the differential speed of the input and output part of the respective clutch begins and takes place grinding. 2. Gear unit according to claim 1, characterized in that the at least at least two clutches (11, 15; 51, 52, 55, 56; K1, K2) friction clutches,  such as friction clutches and / or magnetic powder clutch gen, are. 3. Gear unit with a multi-range structure according to one of claims 1 or 2, characterized in that a control unit ( 100 ) with sensors ( 415 , 416 ) and / or other electronic units is in signal connection and the translation of the continuously variable transmission ( 110 ) and the transferable re drives torque of at least one clutch ( 111 , 112 ). 4. Transmission unit according to claim 3, characterized in that the control unit ( 100 ) has a central computer unit. 5. Transmission unit according to one of claims 1 to 4, characterized in that control means ( 100 ) for actuating and actuating adjusting cylinders and / or pressing cylinders ( 113 , 114 ) of the continuously variable transmission ( 110 ) and the at least one clutch ( 111 , 112 ) are available, which are operated hydraulically, mechanically and / or by electric motor. 6. Transmission unit according to one of claims 1 to 5, characterized in that a range change of the continuously variable transmission ( 1 a) by means of at least one slipping clutch at differential speed between the input and output part of this clutch. 7. The method for a transmission unit according to one of claims 1 to 6, characterized in that a range change of the continuously variable transmission ( 1 a; 58 ) by means of at least one slip-controlled clutch ( 11 , 15 ; 51 , 52 , 55 , 56 ) at a differential speed between an output and input part of one of the at least two clutches ( 11 , 15 ; 51 , 52 , 55 , 56 ) is initiated or takes place. 8. Procedure for changing the transmission paths of a multi-range transmission bes with an input shaft (e), an output shaft (a) and two by means of we at least one friction clutch (K1, K2) switchable transmission paths between the input and output wave, which transmission paths continuously variable transmission (CVT) included, which is arranged such that the differential speed of the respective open clutch (K1 or K2) at ei ner certain translation of the continuously variable transmission 0 is there characterized in that switching between the transmission path the at a differential speed of the clutch to be closed (K1 or K2) takes place, the differential speed is such that by closing the Coupling (K1 or K2) a range switch in the direction of larger or lower gear ratio without interrupting the tractive force. 9. The method according to claim 8, characterized in that in a Verrin reduction of the ratio of the multi-range transmission in the range of the open clutch (K1 or K2) before reaching differential speed 0 between The input and output part of this clutch is closed.   10. The method according to claim 8 or 9, characterized in that at one Reduction of the ratio of the multi-range transmission in its thrust reaches the open clutch (K1 or K2) after going through the differential rotation Number 0 between the input and output part of this clutch closed becomes. 11. The method according to any one of claims 8 to 10, characterized in that with an increase in the translation of the multi-range transmission in the Pull range the open clutch (K1 or K2) after passing through the difference Speed 0 between the input and output part of this clutch closed will. 12. The method according to any one of claims 8 to 11, characterized in that with an increase in the translation of the multi-range transmission in the Thrust range the open clutch (K1 or K2) before the difference is reached Speed 0 of the input and output part of this clutch closed becomes. 13. Multi-range transmission for performing the method according to one of claims 8 to 12, characterized in that a first transmission path between the input shaft (e) and the output shaft (a) contains a first clutch (K1) and a differential gear ( 507 ), that a second transmission path between the input shaft and the output shaft, the continuously variable transmission (CVT), whose output shaft is rotatably connected to a support member of the differential gear ( 507 ), and a second clutch (K2) between the output shaft and the output shaft (a) contains, the first clutch (K1) being closed and the second clutch (K2) open in a first working range of the transmission with large gear ratios and the first clutch (K1) open and the second clutch (K2) in a second range with smaller gear ratios closed is. 14. Multi-range transmission according to claim 13, characterized in that the differential gear is a planetary gear, the sun gear ( 517 ) is connected to the output shaft of the continuously variable transmission, the planet gear carrier ( 515 ) via the first clutch (K1) with the input shaft (e) is connected and the ring gear ( 513 ) is connected to the output shaft (a) and via the second clutch (K2) to the planet carrier ( 515 ).