EP0721404A1

EP0721404A1 - Continuously variable transmission, in particular with power distribution

Info

Publication number: EP0721404A1
Application number: EP95925691A
Authority: EP
Inventors: Michael Meyerle
Original assignee: Meyerle Michael
Current assignee: MEYERLE, HANNELORE; MEYERLE, JUERGEN; MEYERLE, MARTIN PETER
Priority date: 1994-07-14
Filing date: 1995-07-14
Publication date: 1996-07-17
Also published as: WO1996002400A2; DE19525823A1; WO1996002400A3

Abstract

The invention relates to a hydrostatic-mechanical power distribution transmission with several gear ranges. The transmission in question is provided with devices for bridging the hydrostatic converter to improve gear change and optimize travel characteristics and operation, for example, for reverse drive. In addition, a reserve operating system is provided for the eventuality that the electronic system ceases to function.

Description

Continuously variable transmission, especially with power split

The invention relates to a continuously variable transmission, preferably em power distribution with a hydrostatic or mechanical continuously variable converter and its control and regulating device according to the preamble of claim 1 and further independent claims. The transmission allows different driving strategies or driving programs that are user-friendly adjustable or retrievable A converter bridging can be switched at several transmission points and the highest possible braking effect can be used and comfortably controlled via the stepless hydrostatic converter. For switching optimization of range switches, fixed point circuits for converter bridging and others a targeted adjustment correction of the stepless converter is provided

Similar sub-facilities are already known. However, they require more effort in terms of cost, weight and space

The object of the invention is to eliminate these disadvantages, in particular in the case of continuously variable transmissions, in particular hydrostatic-mechanical power-split transmissions. In addition, the advantages of the continuously variable transmission should also be better exploitable by improving the devices known from EP-A-0280 757

According to the invention, this object is achieved by the features listed in the main claims. Further advantageous refinements of the invention emerge from the subclaims and the description.

The invention is explained using exemplary embodiments with reference to drawings. FIG. 1 shows a circuit diagram of the control and regulating device for a continuously variable transmission with several shift ranges. FIG. 2 gearbox construction with device for hydrostatic bridging of a continuously variable, in particular hydrostatic, gearbox with power split. FIG. 3 gearbox diagram of a continuously variable hydrostatic power split gear

Figure 4 Gearbox construction with hydrostatic braking device (hydrostatic retarder)

Fig. 5 u 6 gear with device for braking energy recovery Fig 6ι 6k 6m diagram driving control

Fig. 7 and 7a adjustment, speed, torque, pressure curve during a switching sequence. Fig. 7b functional representation for fixed-point circuit KB Figure 8 circuit diagram

Figure 8a functional representation for automatic starting

FIG. 1 shows the basic circuit diagram of a continuously variable, in particular hydrostatic power split transmission with several shift ranges. A transmission diagram of such a transmission is shown in FIG. 3.

As can be seen from FIG. 1, the transmission adjustment is via a signal c or / and via a so-called EP adjustment, according to FIG. 8, resulting from two or more operating signals, in particular engine speed signal b and accelerator pedal signal or engine control signal a or throttle valve angle DW two input signals Ci and C2 for adjusting the hydrostatic force possible Cl and C2 are electrical variables which act on an electrical adjustment with a proportional magnet and are proportional to the adjustment size of the hydrostatic unit

The accelerator pedal signal a can be a throttle valve adjustment signal or can also serve as an engine control signal k, which is connected to the engine via the control device 5, the signal k being identical to the accelerator pedal signal or a modulated variable, depending on specific operating parameters, represents

The invention further relates to a motor vehicle transmission, in particular with a power split, which consists of a stepless converter 4c, according to FIG. 2; 3, 4, δ preferably a hydrostatic converter, which consists of a first and a second hydrostatic unit, both units preferably forming a common structural unit and drive or output of the stepless converter 4c, depending on the embodiment, via direct drive or via intermediate drive wheels Power is divided on the input side into two power branches, one power branch flowing through the stepless converter and, before the transmission output, possibly summed up again in a summation table 5c with the other power branch. Power split gearboxes consist of one or more shift ranges The shift from one to the other takes place λ or preferably at one end adjustment point of the hydrostatic unit, whereby the adjustment size remains unchanged during the shift phase, with the exception of any slight adjustment corrections. As shown in FIG. 3, the hydrostatic drive four times over the entire transmission range from one adjustment maximum to the other adjustment maximum. In this transmission according to FIG. 3, when the clutches K5 and KV are closed and after clutch 1 is closed, the hydrostat is at its maximum negative Adjustment size set To start, the hydrostatic is now swung back to "zero" and beyond to its other end of adjustment, positive adjustment maximum, where at the end of the first and at the beginning of the second shift range with synchronous operation of all clutch gears, the second area the second range is switched by closing the clutch K2 and opening the clutch Kl. Now the hydrostat is reduced again within the second switching range to "zero" and beyond that to its negative adjustment maximum, around the third switching range by closing the clutch K3 and opening the clutch KV to switch. The third area is then again controlled by regulating the hydrostatic by "zero" and further up to its positive adjustment maximum, where at the end of the third switching range the clutch K4 and the disengagement of the clutches KV and K3, the fourth area, are now switched. By regulating the hydrostat back to the opposite adjustment maximum, corresponding to the negative adjustment end of the hydrostat, the hydrostat is driven through fully for the last time until the transmission's end point of transmission is reached. In this transmission, the mechanical power component is conducted via spur gear stages 26c and the hydrostatic power component via gear stage 10b, hydrostatic converter 4c and drive train 7c with gear stage 228 to summation gear 5c. The summation gear is designed here as a multi-shaft planetary gear P1, in which the mechanical and hydraulic power is added up. In the first and in the second shift range, the mechanical and hydraulic power flows via the second planetary gear P2 with the clutch KV closed. For the reverse range, the first and the second shift range are made possible by closing the clutch KR by reversing the direction of rotation in the planetary gear P2.

The adjustment maximum of the hydrostatic mentioned in each case defines the point at which the shift into the next driving range takes place, which does not necessarily have to be the adjustment end of the hydrostatic, but can also lie somewhat in front of it, in order, for example, to be able to compensate for load-dependent slippage of the hydrostatic transmission. Also defined under synchronous operation of the clutch elements to be closed is not absolute synchronous operation, but the synchronous operation range, which can also include wanted or unwanted synchronous operation errors that can be bridged or still recorded by the shift or range clutches

Gearboxes of this type are described in more detail according to DE 40 27 724, DE 41 06 746.EP 0 386 214, US 5,267,911, which are part of this invention. The invention represents, inter alia, an improved embodiment of this known transmission and the invention according to DE-A 44 17 335. EP 0599 263. The description of the latter two documents are part of this patent application and serve to explain details in more detail.

The invention provides, inter alia, to improve the efficiency, the noise behavior and / or to create an effective integrated brake system. to realize one or more non-hydrostatic operating points, in particular fixed transmission points. For this purpose, the hydrostatic system is switched off or bridged at one or more operating points, which are in particular in the main operating areas, by appropriately designed devices in order to put the latter into an inoperative state. This switch-off or bridging device is implemented in the form of a hydrostatic blocking device KH or / and an area block circuit or / and a stabilizing device KD with or without direct throughput without a hydrostatic power component.

Furthermore, the transmission is equipped with a braking device which is operatively connected to the hydrostatic bridging device or transmission fixed-point circuit and the stepless converter 4c, as described in part in DE 44 17 135 AI FIG. 4 shows an example of a power split with a hydrostatic converter 4c and a summation gear 5c. The summation gear 5c can also have the function of a branching gear, which is why the term 'summation zbranching gear' is used below. The hydrostatic converter consists of a first hydrostatic unit A adjustable Volume and a second hydrostatic unit B preferably constant volume. Both hydrostatic units A and B preferably form a common structural unit which is in direct connection with the drive shaft 1c or via drive wheels with the drive shaft 1c and on the opposite side directly via drive wheels with a summing gear 5c. The summing gear is preferred formed as a planetary gear, to which, depending on the design, a further gear 5d, with or without switching devices, for example for range shifting for shifting several driving ranges, can be assigned Power on this transmission is divided into a hydrostatic and a mechanical branch on the input side. The hydrostatic power component flows via the drive wheels and intermediate links 227 via the stepless converter 4c and the drive wheels to the summation gear 5c. The mechanical branch is fed directly or via intermediate links into the summation gear 5c by adding up hydraulic and mechanical power flows and jointly reaching the output shaft 2c. The stepless converter or the hydrostatic device 4c is equipped with a hydrostatic lock-up device as a hydrostatic locking device in the form of a brake or clutch KH, which serves to drive the drive shaft 7c to hold the second hydrostatic unit B or to couple it to the housing 19c of the stepless converter or a fixed gear part, so that the supporting moments known in power branching, in addition to the clutch or brake, preferably on the gearbox e or converter housings are supported in order to relieve the hydrostatic load or to keep it torque-free and pressure-free. It is also possible to completely separate the hydrostatic shaft 7c of the hydrostatic unit B by a further coupling, not shown

The hydrostatic locking device KH has the task of keeping the stepless converter 4c or the hydrostatic unit in the hydraulically inoperative operating states with hydrostatic adjustment size "zero" torque or load-free. This is solved in such a way that the torque support force from the summation of branching unit 5c in the hydrostatic unit Zero position, which is generally in the middle of each shift range, is not supported on the hydrostatic elements but on a corresponding intermediate brake or clutch element with respect to a stationary housing part or gearbox part. In gearboxes with several shift ranges, the hydrostatic valve is moved through several times within its% correct adjustment range , with the hydraulically powerless state in neutral position, that is to say with zero adjustment of the hydrostatic unit, corresponding to the neutral hydrostatic position, occurring within each switching range. This operating point is usually in a w real operating range of the vehicle, in which a particularly good efficiency is required The adjustment characteristics of the hydrostatgetebes are described in more detail in the power branching targets according to DE-A-40 27 724, DE-A-41 06 746 and PCT / DE 89 00 586, which, as already mentioned, are part of this invention

In order to prevent hydrostatic tension in this neutral adjustment position of the hydrostatic device, a bypass valve 114c is provided, which is connected between the two working pressure lines of the two hydrostatic units A and B. This bypass valve can be actuated automatically or also manually when the hydrostatic blocking device is switched, so that both working pressure lines are depressurized or without differential pressure. The hydrostatic locking device or the clutch brake KH and the bypass valve are controlled by the same control pressure, but the bypass valve is only activated after the clutch / brake KH is closed, such that the pressure pressure signal after the clutch KH closes the signal or the control pressure Activation of the bypass valve triggers The hydrostatic locking device KH can be switched automatically or manually, e.g. depending on a defined dwell time of the transmission in the hydrostatic neutral position or in the vicinity of, for example, a maximum of 8% of the current gear ratio, with a pre-programmed time variable for this dwell time, z 2 seconds, triggers the corresponding control signal for the Hydrostat-Sperreinπchtung, such that a largely seamless continuous adaptation of the corresponding translation and the engine speed to the desired speed. For manual shifting, it is provided to indicate this operating state and the shifting ability to the driver preferably via an optical or acoustic signal. The hydrostatic lock can also be released in various ways, for example by means of an accelerator or accelerator pedal signal, that is to say when the accelerator pedal position is changed or by a load-dependent signal or by various signals which are determined by variable operating values with a view to optimizing the Fuel consumption can, for example the driving control should be designed in such a way that the get ebe efficiency line and the fuel consumption of the engine are never stored and the vehicle control, depending on the respective operating situation, decides whether the following transmission ratio point should be controlled with a hydrostatic neutral position or not. Depending on the type of vehicle, a further parameter can be stored or programmed as a decision factor depending on the load or noise behavior of the transmission. This can be useful, for example, when using a car

The invention further provides for the hydraulic power branch to also be switched off at the translation points of the range switching points. This means that at the end of the old switching range and at the beginning of the new switching range, the clutches KB remain closed for both ranges and the hydrostat is fixed in this adjustment size and set without load, e.g. by simultaneously actuating the above-mentioned bypass valve or / and a precise alignment or Correction of the Hydrostatver position, such that the two hydrostatic working pressure lines are depressurized or without differential pressure. In this switching state, the power is transmitted purely mechanically, specifically via the clutches or coupling devices of the two adjacent or adjacent switching areas. The switching signals for this circuit can be transmitted with the same signals as for the hydrostatic Locking device KH described, can be realized. In a transmission, e.g. B. with four forward driving ranges, as shown in Fig. 3, seven translation fixed points can be switched in this way with no load hydrostat.

As mentioned, the invention provides, for power branching devices, a stabilizing device KD or hydrostatic bridging device which holds fixed translation settings at one or more transmission points at which the hydrostatic power flow can be switched off to further improve the efficiency. As shown in Figure 4, z. B. the output shaft 2c via a gear stage 10b with the drive shaft lc via an intermediate shaft 227 by engaging a clutch KD in driving connection to put the hydrostat after the clutch without load. For further important transmission points, which have a high operating share, further transmission stages (not shown) with a correspondingly assigned clutch can be provided.

An embodiment according to FIG. 3 shows e.g. a stabilization or hydrostatic bridging device, in which a direct through-drive, without tooth mesh or tooth-rolling power, is produced between the drive shaft lc and the output shaft 2c by means of a clutch KD and thus the converter 4c and the summation-branching gear 5c are set in a no-load condition .

The stabilization device or hydrostatic lockup device KD can also be implemented with two or more clutches (not shown) in order to completely decouple the continuously variable converter and the summation branching gear. When combined with an already described bypass valve and / or a corresponding hydrostatic adjustment device with targeted adjustment control, the second clutch can be dispensed with.

In the event of an emergency. the constant translation setting or constant driving speeds require, the invention provides an improvement of the device according to the German patent application DE 41 04 167, claim 17. In order to prevent frequent switching on and off in the switching range of two adjacent range switches, the fixed point circuit KB described serves by closing both range clutches, for example K1 and K2, as shown in FIG. 7b in accordance with the operating phase Ph 2. Depending on one or more operating variables, the fixed point circuit KB is automatically triggered, the operating variable being a difference value of the hydrostatic adjustment volume ΔV or ΔnHy or / and a difference value for the load signal Δp or / and a pre-programmed time-difference signal or other signals . The corresponding aforementioned signal sizes can be preprogrammed and additionally influenced depending on various operating values, such as operating temperature, accelerator pedal signal or others. The functional sequence is such that, as shown in FIG. 7b, the output speed nHy of the second hydrostatic unit B is automatically increased in the vicinity of the translation fixed point KB while the driving speed or output speed Nab remains the same, while the engine speed nMot is reduced accordingly by the difference value delta nMot. According to FIG. 7b, for example in the first operating phase Phl, the first range clutch Kl and at Fixed point circuit according to operating phase Ph2, the clutch K1 and K2 must be closed and in the third operating phase Ph3, the clutch K1 is again closed and the clutch K2 is opened. The difference values delta nHy or delta nMot for the drive motor can be preprogrammed in any size or in any ratio and, depending on the type of vehicle, vary in size from, for example, 5% to 10% of the respective reference size. Depending on the gearbox design, the speed variables nHy and nMot can be in different relation to each other, whereby, for example, as shown in Figure 7b, the motor speed variable nMot is smaller than the hydrostatic speed variable nHy or, in a relation (not shown), the speeds lie so that they are in phase the fixed point circuit Ph2 rotates the engine speed nMot synchronously with the hydrostatic speed nHy .., as would be the case with the relevant planetary gear members HMot and sHy of the transmission according to FIG. 3 in the fixed point circuit K1 K2 by block circulation of the summation planetary gear Pl.

The clutch for the hydrostatic bridging devices KH: KB; KD can be implemented in various ways and can be arranged, for example, for the hydrostatic locking device KH as desired on one of the intermediate links or drive elements 7c between the second hydrostatic unit B and the summation gear 5c. The KH couplings; KB; KD are preferably designed as a positive coupling as in PCT publication DE-A-87/00 324, DE-A-41 26 650 AI and in European PCT application DE 88/00 563, which are part of this invention described. The clutch is characterized in particular by the fact that it has form-fit switchable clutch elements with a clutch toothing with or without deflection toothing and that by means of a hydraulically actuatable piston which is displaceably arranged on a clutch carrier, the shifting in synchronous operation or in the synchronous operation range is also possible at a certain relative speed. It is also possible, as described in the known publications mentioned above, to provide additional synchronizing devices. This positive clutch has the advantage that it is almost drag-free, since there are no friction elements. But it is also possible to use the clutch as a friction clutch in the form of a cone clutch, such as. B. shown in DE-A-41 26 650 to use. This clutch can also be largely free of drag loss since the conical effect means that the friction surface is relatively small. Under certain circumstances, the use of a multi-plate clutch in a known design can also be designed meaningfully. Another type of positive coupling with mechanical switching elements, e.g. B. by means of shifting claw, shift sleeve and / or with servo-reinforced shifting elements is, depending on the selected gearbox design, usable. In a form not shown, the clutch KH for the hydrostatic locking device is alternatively arranged in the summation gear 5c. In the embodiment according to FIG. 2, it is advisable to arrange the clutch KH on a shaft 73c connected to a traction booster 77c. Here, traction booster 77c and clutch KH can be combined into a common structural unit in a space-saving and cost-effective manner.

The hydrostat is in all of the devices already described for switching off the hydrostatic operation via the bypass valve 114c; 216 or / and to be set without load by a suitably trained hydrostatic adjustment control. θ Within the fixed point circuit, the hydrostatic transmission is based on the theoretical

Adjustment volume-large Vth is set or adjusted so that no quantity of differential oil is exchanged between the working pressure lines 206, 207 when the bypass valve is open, or without a switched bypass valve 114c, 216 or a missing bypass valve, the working pressure lines 206, 207 are almost free of differential pressure.

In a further control variant for the fixed point switching, according to the invention, the hydrostatic adjustment can automatically and continuously adjust itself to a new adjustment size corresponding to a displacement-large Vneu, which varies depending on the drive torque or the respective changing load state of the engine and transmission, with the bypass valve preferably switched. that when you leave the fixed-point circuit, ie at the start of the new circuit or range circuit, the correct adjustment size or displacement volume Vneu is immediately available, which corresponds to the torque-free state of the old clutch Kl; K2 or clutch KH; KD and the cheapest adjustment size Vneu for the opening signal of the corresponding clutch in an almost torque-free condition. The switching sequence for leaving the fixed point switching and switching to the new stepless switching range is carried out according to the invention in this switching variant such that with automatic torque-dependent constant adjustment of the adjustment to the size Vneu takes place in such a way that first the bypass valve closes and then the opening signal for the old clutch is initiated when the clutch clutch concerned is in a torque-free state. When the bypass valve 114c, 216 is closed automatically. For example, when shifting from KB to the stepless range, the full torque is shifted to the new clutch Kl or K2 and the old clutch set torque-free with the correct Vneu and open. When switching from the fixed point circuit KH or KD to the subsequent continuously variable switching range, the relevant clutch KH; KD relieved of the torque and then opened by a corresponding opening signal. To optimize the switching quality, the bypass valve 114c, 216 is alternatively designed in such a way that a continuous but nevertheless rapid pressure build-up is ensured during the closing process. The continuous pressure build-up can have various characteristic curves and, for example, correspond to a fixed specification by known means such as throttle damping, steaming grooves, etc. or vary depending on one or more operating values, in particular load-dependent values, for example due to the hydrostatic pressure. Electrical-electronic controls can also be useful for a seamless switching sequence, especially in connection with the hydrostatic retarder described. When executing the first-mentioned variant, in which the hydrostatic transmission is set or regulated to Vth within the fixed-point circuit, the two working pressure lines 206 and 207 being virtually free of differential pressure without a switched or missing bypass valve, the switching sequence for exiting the fixed-point circuit KB becomes infinitely variable

Range shift carried out in such a way that the full torque is first shifted to the new clutch K1 or K2, such that the hydrostatic adjustment is first adjusted to the new adjustment or displacement volume Vneu depending on the current load condition, whereby the old clutch is torque-free and receive the opening signal. The opening signal for the old clutch can be triggered automatically depending on Vneu.

The definition “new clutch” in the fixed point circuit KB means the clutch Kl or K2 loaded after leaving the fixed point circuit and with “old clutch” the clutch Kl or K2 to be relieved of the torque and then opened. Within the fixed point circuit KB, both clutches Kl and K2 are loaded with torque

The torque-dependent shift correction, in particular derived from the engine torque and / or drive torque, will be described in more detail later

All of the above-mentioned devices for switching off the hydrostatic power flow reduce the power loss losses in order to improve the efficiency.

The functional sequence, which is described in more detail in DE 44 17 335 AI, is as follows: When the brake is actuated, after the gearbox jerk control has been carried out, as already described, the following or most favorable transmission fixed point is adjusted and switched, with the hydrostatic Getnebe is initially in a no-load condition. For example, at the fixed translation point via the range block circuit KB, the hydrostatic unit A is generally fully pivoted out in this state, as a result of which both hydrostatic units keep the corresponding amount of oil in circulation at the same speed without differential pressure within the converter unit only after adjusting the hydrostatic unit A to a smaller one Volume, the differential oil quantity is fed into the brake pressure circuit 206 or 207. If the adjustment unit A is adjusted to an adjustment size "zero", the entire pumping capacity of the second hydrostatic unit B, which is generally designed as a constant unit, is fed into the brake working pressure circuit 206; 207 led. If the hydrostatic adjustment is continued through "zero" and beyond, the adjustment unit A also works as a pump, at the end of its adjustment size, that is to say with a full adjustment volume. same pump output as the constant unit B delivers. In this state, the highest braking energy can be transmitted at twice the pump power, with both units A and B being driven via the braking torque via their drive shafts 7c and 6c and associated drive trains 227, 228. Both hydrostatic units A and B can also be of different sizes are formed, the respective braking powers being different according to their size and their associated speed. If the second hydrostatic unit B is also designed as an adjustment unit, further variations are possible, for example in such a way that both units are adjusted simultaneously or first the unit B and then the unit A, depending on the operating situations, can be sensibly regulated in their adjustment variables. In the known transmission designs mentioned at the outset, it makes sense to design the second hydrostatic unit B as a constant unit. For the operating state in which the transmission fixed point is fixed by the hydrostatic locking device and the clutch KH being closed, braking energy transmission is only possible via the first hydrostatic unit A, which is driven by the corresponding drive train 227. In most operating situations this is sufficient. In the event of a higher braking energy demand, this clutch KH can be opened and another translation fixed point can be actuated very quickly by the automatic interaction of the control device. To achieve a continuous brake transition, the invention provides for this to automatically switch on the service brake briefly. so that a smooth, jerk-free braking behavior is guaranteed over the entire transmission range. If, for example, a change from a fixed translation point KH to a fixed translation point KB is carried out during the braking phase, the service brake is first activated via the automatic brake control, so that a largely no-load state in the hydrostatic transmission is carried out with simultaneous automatic resetting of the hydrostatic unit A. In accordance with the automatic brake energy consumption via the hydrostatic transmission, the braking effect of the service brake increases continuously. In order to find the aforementioned fixed translation point KB by controlling the corresponding range block circuit, the hydrostatic transmission is now brought into the corresponding end position or final adjustment variable, after which the service brake immediately after completion of the switching of the above-mentioned fixed translation point, with simultaneous readjustment of the hydrostatic transmission and taking over the hydrostatic Brake performance the service brake is continuously released. This functional sequence can be implemented using appropriately coordinated signal variables from a plurality of operating variables such as brake pressure signal, hydrostatic pressure signal, adjustment signal of the hydrostatic transmission and / or engine speed signal and / or further signals.

In addition to the hydrostatic converter 4c, the hydrostatic braking device consists of a first check valve 209, via which the oil flow of the respective high-pressure line 206 or 207 is passed to a first switching valve 203 and a downstream pressure control valve 204. The switching valve 203 is switched via an opening signal 214 to release the hydrostatic braking function. The pressure control valve 204 is controlled via a variable control signal 215, which is dependent on the magnitude of the braking force and determines the hydrostatic pressure. The heat exchanger 205 is arranged downstream of the pressure control valve 204, which receives the heated oil flowing from the pressure control valve via a corresponding line 217 and re-introduces the cooled liquid into the working pressure circuit of the brake system via a further line 213 and a corresponding check valve 210. In the case of stepless hydrostatic-mechanical branching transmissions, it is characteristic that after each change of range or after each range shift, the hydrostatic units A and B interchange in their function as pumps and motors. The load-dependent speed slip of the hydrostatic transmission or the shaft 5 connected to the hydrostatic unit B has the reverse effect after each range shift, which must be corrected by the adjusting device within the shift phase in order to ensure a smooth shift.

The object of the invention is to provide a switching device, preferably for automatically switchable transmissions, in particular for continuously variable branching transmissions of the above-mentioned type with form-fitting clutches with or without deflection teeth or friction clutches with conical friction surfaces, as known from DE 41 62 650, or also with known multi-plate clutches ensure the high switching quality without interrupting the load

The leakage losses of the hydrostatic transmission, as mentioned at the outset, result in an inevitable speed slip of a hydrostatic shaft 7c. This speed slip, in conjunction with a stepless power split transmission with several driving ranges within the range shift, as shown in FIG. 7, has the effect that, for example, during train operation To achieve the synchronous state of the clutch genders to be switched, the variable V alt by dimension X at the switching point must be greater than the theoretical value in order to reach the synchronizing point of the coupling elements to be switched at switching point S. The size of the adjustment or the maximum adjustment volume must be dimensioned correspondingly large when designing the gearbox.As a result of the above-mentioned function reversal from pump to motor and vice versa after switching to the next switching range, the speed slip also has the opposite effect, which means an adjustment correction size by the dimension Y and thus Adjustment size V new corresponds to the correction sizes X and Y usually have different sizes, due to the respective gearbox design and area sizes corresponding to the different sizes of the hydrostatic pressures Δpl and Δp2 or Δp old and Δp new at the end of the old and start of the new shift range. During the shift phase, the hydrostatic transmission must be corrected in accordance with the load state by the correction dimension X + Y = Z. According to a shift example as shown in FIG. 7, where B1 means 1 and B2 means 2, the functional sequence is as follows.

In the case of an upshift under load of B1 in B2, the switching signal for closing the new or second range clutch is triggered as soon as the coupling member which is in drive connection with the second hydrostatic unit B has reached synchronous operation with the clutch gethers to be shifted at the switching point S. The hydrostatic variable 'Υ old' is larger by a dimension X than the theoretical value V th. Now the shift into the new or second range or the closing of the second range clutch after the synchronization pulse has taken place, the old or first range clutch being closed The hydrostatic adjustment is now reduced by the dimension Z within both closed clutches until the setpoint SKI is reached, after which the signal to open the old or first range clutch is given. Only then is the fuel ratio changed with further hydrostatic adjustment to the new one to pass through the second area In order to take into account the different speed slip sizes of the hydrostatic transmission at the end of the old and at the beginning of the new shift range with the correspondingly different individual adjustment correction variables X and Y for shift optimization, the invention provides an adjustment control that is adapted to the respective design conditions before, according to which an adjustment or volume correction is effected for the adjustment variable or the displacement volume V new of the adjustable hydrostatic unit A, namely in terms of size according to the relationship

1) V new = V old - (V old - V new). fz

2) fz = Δp old + ΔP new = correction factor

Δp old

The correction factor fz represents a magnification factor in relation to the individual correction variable X or Y of the old switching range, from which the total correction variable Z is calculated. The correction factor fz is a fixed value, which is determined by the respective mechanical transmission ratio and can have different sizes for each of the translation fixed points of the individual range shifts. That is, e.g. in a four-range transmission, as shown schematically in FIG. 3, with a specific gear or range gradation, for an upshift from range 1 to range 2 (range shift 12) the correction factor fz = 1.85, for the shift 2/3 = 3.04 and for the circuit 3/4 = 2.75, "fz" is thus determined by the size ratio of the individual switching ranges to each other or, as already mentioned, by the defined mechanical ratios, whereby the different pressure ratios of the Hydrostatic transmission are defined at the end of the old and at the beginning of the new shift range with the load state remaining the same. The above-mentioned relationship 1) applies to all switching states, whether pulling or pushing or upshifting and downshifting. However, in downshifts, the total correction quantity Z is not calculated from X but from Y, which makes the formula 2 »clear. For the downshifts e.g. 8 the above-mentioned four-range gearbox according to FIG. 8 with the same above-mentioned transmission design, fixed correction factors fz for example for the range shift 2/1 = 2.17, for the range shift 3/2 = 1.49 and for the range shift 4/3 = 1, 57.

To improve the known switching correction device acc. DE 41 04 167 AI provides this invention with further details such that operational changes within the switching phase, for example changes in the accelerator or accelerator pedal, changes in load, etc., are also taken into account. For example, when the accelerator pedal is released, an immediate opening signal is generated for the clutch in question, the opening signal being able to relate to both the old clutch and the already closed new clutch. In this case, for example, information that may have been stored beforehand before closing the new clutch is used to determine the size of the shift correction X; Y or Z are ignored or adapted accordingly in order to be able to take into account new, for example suddenly occurring, operational changes within the switching phase. The information for the size of the switching correction can, as described in the known DE mentioned above, a load signal. Time signal and other quantities. It is thereby possible for the old clutch to remain closed, for example when the shifting process has already been initiated, and the clutch is already closed closed new clutch opens again. This device is also very advantageous for the “fixed point circuit KB” described, in particular in the case of constant travel setting and / or constant gear ratio setting. Another operating state, on the other hand, is optimized in that the load decrease occurring during the switching phase, for example by reducing the driving or Accelerator pedal or sudden changes in the driving profile the information given before the shift phase is ignored for the shift correction quantity in order to enable the old clutch to be opened immediately, in this way a largely seamless range shift is achieved regardless of different operating changes within the shift phase Another embodiment is the adjustment correction for switching optimization

Operating values of the drive motor M controlled / regulated. Determining the size of the adjustment correction X; Y; Z is the respective or instantaneous drive torque Tan of the transmission or the engine torque Tmot. As with all of the above-mentioned solutions, the new clutch is pushed when the new clutch closes, in the synchronous state of the clutch elements of the new clutch, preferably two or more speed sensors determining the synchronous state by comparing the speeds of at least two transmission elements and the switching pulse for the new clutch trigger. The instantaneous drive torque of the transmission or engine torque Tan determines the load size of the hydrostatic transmission and the corresponding speed slip of the hydraulic motor / pump and thus also the size of the adjustment correction required in each case within both closed clutches. Each drive torque is therefore also assigned a specific adjustment variable or displacement volume Vneu, which corresponds to the torque-free state of the old clutch, after which the opening amount for this clutch is triggered. Torque changes within the switching phase, with both clutches closed, are automatically taken into account in this correction device, since the instantaneous drive torque Tan or engine torque Tmot always determines the opening signal of the old clutch or triggers corresponding corresponding signals to open the old clutch . Regardless of whether it is a train upshift, pull upshift, push upshift or push upshift, the system recognizes the most favorable opening point or the new adjustment volume Vneu for triggering the opening signal of the old clutch. The detection in the control device as to whether pushing or pulling operation takes place by means of engine parameters or load variables / signals, and possibly also external influencing variables, with each engine torque Tmot and engine speed n mot having a specific control variable such as throttle valve position during pulling operation; Accelerator or accelerator pedal position, accelerator pedal change speed, temperature, possibly also air pressure, etc. assigned is. For example, if the accelerator pedal / accelerator pedal is suddenly released within the switching phase, the immediate opening signal at Vth can be issued because the drive torque or the engine torque immediately drops to zero or even assumes negative torque, although Valt and correction-sized X had maximum size at the start of the shift.

In overrun mode, the system also recognizes the respective operating state in that when the overrun torque is reached, the engine is correspondingly toured and, depending on the speed, corresponding signal b, a corresponding braking torque or negative engine torque or overrun torque size is recognized, and from the corresponding signal sizes b, a or brake signal f, torque size Tmot; Tan and torque direction are determined and from this the shift correction size and correction direction and Vneu for opening the old clutch are determined and signaled. In overrun mode, the correction sizes and correction directions are reversed, the displacement volume or manipulated variable Valt being smaller than Vneu when upshifting and Valt greater than Vneu when shifting up. This corresponds to the general characteristic switching correction behavior in such hydrostatic-mechanical, but also purely mechanical power-split branches.

As explained earlier, the speed slip sizes of the hydrostatic transmission before and after the range shift with the same input and output torque at each range switching point (upshifts 1/2; 2/3; 3/4 or downshifts 4/3: 3/2; 2/1) be very different depending on the gearbox design and division of the area. The correction size ratios X to Y are correspondingly different. Accordingly, the correction sizes or correction size ratios X to Y are programmed in the control system. each drive torque is assigned and preprogrammed a separate manipulated variable or displacement volume Vneu for each range switching point, the dependency of changing load conditions and other factors within the switching phase can be corrected, so that a switching operation without switching shocks is ensured in all operating states.

Depending on the type of engine control, whether power or speed control, e.g. RQ, RQV or another type of control, the signal and signal sizes suitable for determining the engine torque are programmed in the drive control or control and regulating device. For example, with RQ control, each throttle valve or accelerator pedal position and given engine speed is assigned a specific engine torque, so that throttle valve or accelerator pedal position signal and engine speed signal provide information about the respective engine torque, after which the new displacement volume or the adjustment size Vneu is determined and from this the opening signal for the old clutch can be initiated. With RQV control, each accelerator or accelerator pedal position corresponds to a specified engine speed regardless of the engine torque. With this type of control, it is therefore necessary to use an appropriate signal to determine the engine torque, which corresponds to the degree of completion of the fuel injection or a similar signal size that is suitable for determining the torque.

In this correction variant, in contrast to the variant described earlier, it is not necessary to determine or calculate the adjustment correction size Z from a hydrostatic pressure signal or a correction size X or Valt given before the start of switching, but the opening signal can always be off the currently effective drive torque Tmot or Tan are determined. An appropriate adjustment sensor or sensor, which signals the adjustment angle or adjustment path of the hydrostatic transmission, generally ensures the precise realization and signaling of the new manipulated variable or Vneu

Alternatively, the known displacement pressure or electrical displacement current quantity can also be used for the displacement variable or displacement volume measurement, provided that these are suitable for determining the correct opening signal for the old clutch.

A pressure sensor for recording the respective hydrostatic pressure is not required with this correction variant

All shift correction devices described in this patent application can be used both for static-mechanical as well as purely mechanical power split systems. In the case of a mechanical power split cabinet, the respective torque ratios on the stepless converter apply to the correction ratios X and Y, the torque ratios corresponding to the pressure ratios of the working pressures of the hydrostatic transmission

The brake signal f effective for the transmission jerk control can be dependent on the brake actuation force and / or in a more or less large dependence on the engine speed, preferably in the lower speed range and starting range, for example when the brake is released, the brake portion via the service brake is very low or almost zero Depending on the type of vehicle, the brake signal f can therefore represent a fixed or variable characteristic that can be varied according to a certain operating parameter, depending on a particular braking characteristic

The brake signals 113, 217; 215 of the braking, control and regulating device for the retarder brake system, preferably hydrostatic retarder according to FIGS. 2, 4; 5; 6, or a retarder of a known type, can advantageously be brought into direct or indirect connection with the brake signal f or be effective as a brake signal f. An improvement in the range switching within the braking or / and coasting operation is achieved by the combination of the transmission-side braking via the influence of the brake signal on the transmission ratio and the interaction with the bypass valve described. Due to the influence of the brake signal, the engine speed is increased due to the corresponding change in the transmission ratio, which at the same time has a positive effect on the spontaneity of the shifting sequences and the adjustment speeds, since higher speeds result in control pressures and control oil quantity, both for the hydrostatic adjustment and for the clutch shifting elements is improved. Through the interaction of the brake signal, transmission signal and / or engine speed signal and / or, where appropriate, an automatic filler or throttle valve position signal and, if appropriate, further operating signals, a harmonious, comfortable range shift is achieved, even in extreme braking and thrust situations. For this purpose, the braking components are automatically metered via the normal service brake system and the transmission brake in such a way that a counteraction between the transmission and service brakes is prevented by a correspondingly adjusted metering of the service brake and transmission or retarder brake system being achieved by means of active connections of the aforementioned signals. The amount of engine braking is metered in such a way that the engine noise remains within an acceptable range. For example, at very low driving speeds, the engine braking power can be very low in spite of the relatively high braking force, it being sensible to pre-program a corresponding engine speed control depending on the driving speed and / or the gear ratio or / and the brake size. This is advantageous because at low speeds the amount of gear braking to be supported by the engine is relatively large even at low engine speeds due to the correspondingly large gear ratio. The invention provides for an engine speed reduction with a preferably continuous profile with the vehicle deceleration or with a decreasing profile

Pre-program the travel speed within the braking mode.

The invention further provides an emergency driving device 80 'which, if the

Electronics or / and electrics or the central control device enables emergency operation. For this purpose, a device 80 is provided, which acts independently of the central control and regulating device 5 or the electronics or / and the electrics via a manual control 81 'on the hydrostatic adjustment 18, so that a stepless speed corresponding to a first driving range or is possible according to the maximum adjustment path of the hydrostatic transmission. When used in a continuously variable hydrostatic-mechanical power branching transmission, as shown for example in FIG. 8, in which the first driving range works with power split and when the hydrostatic is already set to a large, preferably maximum, delivery volume in the starting state at zero driving speed, the invention provides that in the event of failure of the electrics and / or electronics, preferably by manual actuation via control lever 81 ', the hydrostatic adjustment 18 to the starting position, ie to the corresponding adjustment variable adjusted and then the corresponding clutch or clutches are closed, eg for forward travel KV and Kl. In this state, a drive connection is now made up to the output shaft AB, the second hydrostatic unit B having a vehicle standstill at a speed that corresponds to the starting position or, depending on the transmission design, an adjustment size between zero and the maximum adjustment volume of the first hydrostatic unit A. The driving speed can now be traversed continuously from zero to the end of the first driving range or the emergency driving range, preferably operated by hand. 8 is described in DE 39 29209 in accordance with FIG. 9 or in DE 43 39 864. Fig. 3 described in more detail.

The above-described emergency driving mode is also suitable for a backward driving mode in a transmission design, as shown in FIG. 8, the clutch KR being closed via the corresponding valve VR instead of the clutch KV.

The valves for controlling the above-mentioned clutches for emergency operation - W, VR, VI - are preferably controlled hydraulically via the corresponding control lines 69 ', 70', 71 '. Electrical control via the usual solenoid valves which are effective during normal operation is also possible in the event that only a partial failure of the electronics is to be protected. In this case, the electrical actuation of the relevant solenoid valves can be implemented directly by the control and regulating device 5 or separately via the emergency drive control device 80 'with appropriate training.

Depending on the requirements of the vehicle, the emergency drive device can be designed in various ways, with the hydrostatic adjustment in a single version being via a single valve - black and white valve - or via a proportional valve or a follower valve with feedback of the actuating variable of the hydrostatic transmission, one of the lever positions of the lever 81 ' appropriate translation size sets. This last-mentioned device enables fixed translation settings within the entire emergency driving area, e.g. certain tasks can still be completed even if the electronics or electrics fail. In the case of the standard version with black-and-white switching, the final speed point or translation point can preferably be operated as constant translation, which, for example, when used in a tractor with a 4-range transmission, as shown in Fig. 8, is about 6 km h.

The first speed range in the case of a stepless power split system with several driving ranges only allows a very low maximum speed of, for example, 6 km per hour when used, for example in work machines such as tractors. In order for transport operations In addition, to be able to drive an acceptable transport speed in the emergency operating state, the invention also provides for a "large emergency driving range" to be implemented, which can in particular optionally be operated as a second clutch / shift combination, which, for example, can be used at a speed of zero to approx For this purpose, the clutches K1 and K4 are closed by the corresponding preselection after activation of the hydrostatic adjustment 18 to the starting position, whereby a direct connection between the clutch Kl and the output shaft AB is established operation "preferably via a proportional valve that assigns a certain gear ratio to each manipulated variable of the emergency lever 81 '. This fast emergency driving area, which is suitable for lower traction requirements, can also be used for a number of tractor applications, e.g. for maintenance work, manure operation, sowing and many other tasks, so that the necessary repair work can be postponed to an economically insignificant point in time .

Both emergency driving areas described above work with power split. Depending on the vehicle requirements, the "slow" or "fast emergency area version" or both can be installed, one or the other emergency mode being selectable depending on the operating situation.

In a transmission with hydrostatic-mechanical power split, in which the first driving range works purely hydrostatic (not shown in the drawings), an emergency driving device of a similar type can be implemented, the hydrostatic already being at zero demand volume in the starting state. After the corresponding range clutch for the first driving range or for the emergency operating range has been closed, the hydrostatic transmission can be used for forward or backward travel by changing the adjusting piston 18 accordingly, depending on the adjusting direction.

In modern motor vehicle drive, the accelerator or accelerator pedal is in direct connection with the control unit 5, the engine control being fed to the drive motor via signals from the drive control, in particular the electronic drive control. If the electronics fail, the electronic control of the motor control can also fail. In order to still be able to implement emergency operation, provision is made to implement the hand gas HG, which is generally present anyway, or by means of a foot-gas connection to the engine which is intended for emergency operation.

The vehicle control can also be designed according to the invention with a view to the emergency driving mode so that a double connection of the accelerator or accelerator pedal is realized with the engine control, such that, for example, for normal operation without defective electronics. Elements or control elements, the engine control via the central electronics or drive control 5 and, if elements of the central control or electronics fail, there is automatically a direct connection of the accelerator or accelerator pedal F to the engine control. In this case, the accelerator pedal and the Central control device 5 directly or indirectly connected to the engine control in order to immediately automatically bring the direct connection of the accelerator pedal to the engine control into operation in the event of a failure of the electronics. The above-described double connection of the accelerator or accelerator pedal F to the engine control also provides for engine control in such a way that, for normal operation, for example, direct control of the engine control via the accelerator pedal F and special functions for influencing or overriding the engine control via the second connection to the central electronics 5 are carried out.These special functions can, for example, briefly lower the engine charge or reset de r Throttle valve or vice versa briefly increase the engine fill to change the speed or / and torque of the engine to improve the switching quality

The emergency driving device further provides that if the electronics fail, an automatic switchover to the emergency operating state takes place during the work or operational use, this state preferably corresponding to the switching state of the emergency operation or that an automatic torque reduction through automatic gas withdrawal and / or automatic opening of the area clutch in question is triggered, whereby the vehicle is brought into idle position. Simultaneously with the failure of the electronics, an optical and / or acoustic signal becomes effective, which indicates the emergency operating state

The invention further provides a device. which enables high starting acceleration and, moreover, a very spontaneously effective turning operation for the use of working machines, e.g. for tractors in front loader applications or wheel loaders For this purpose, as shown in Figure 8a, the driving control is so with regard to a largely continuous output speed or acceleration curve designed that when the direction of travel is selected, the service brake is preferably depressed via the brake pedal 7 and the vehicle starts up when the brake is released, and when the brake is released there is already a very rapid transmission adjustment or transmission change l / i without having to operate the accelerator pedal. The brake pedal is used here as inch "and" accelerator pedal "and is accordingly referred to below as IFA pedal. The IFA function can be preprogrammed as a separately preselectable function or as a permanent function. The change in the translation takes place essentially via the function of the brake pedal signal f, as described in more detail in DE 44 17 335 and shown in this publication in FIGS. 6ι and 6k. The actuation of the brake pedal can take place depending on the actuation force or actuation type with or without activation of the service brake via the function of the brake pedal signal f. Depending on the operation Different driving programs can be preprogrammed.For example, it is advantageous to select this IFA program for turning operation - front loader operation for the tractor - which enables an automatic engine speed characteristic in accordance with nMot II. For normal operation, it may be useful to have an engine speed characteristic in accordance with the characteristic curve To program nMot I as a constant program, according to which there is no or only low engine speed pressure when the brake is released or released.With regard to the different dynamic driving conditions, a variable programe can be made depending on the various operating situations and load conditions mm are realized according to which the engine speed z B varies within both limits nMot I and nMot II depending on the given operating conditions within both characteristics nMot I and nMot II.For example, when driving off and releasing the brake or the IFA pedal with low starting tractive effort or / and low acceleration, a slight drop in engine speed according to nMot I and with high starting traction or / and required high acceleration, an increase in engine speed according to nMot II or vice versa, depending on the type of vehicle, can be realized and preprogrammed, whereby the engine speed and / or engine load is always preferred triggering signal for engine control and / or transmission control

To achieve a high acceleration, it is necessary that in phase IV or 1R. which corresponds to the first driving range, a very fast hydrostatic adjustment or gear change left and within the operating phase 2V or 2R, which corresponds to the first range switching phase, a very fast switching sequence is possible.To achieve this, the invention provides that according to FIG Hydrostat adjustment 261 and 268 is supplied with adjustment regulator VR with high adjustment pressure, for which purpose the high-pressure circuit 206 207 of the hydrostatic transmission can be used. A special valve 263 is used for this purpose, which allows a switching from supply pressure SP to high pressure HD, for which purpose a corresponding control signal 259 is activated becomes. An additional pressure limiting valve 264 is used to limit the adjustment pressure, which ensures pressure limitation, for example at a maximum of 50 bar. This pressure limiting valve 264 can represent a constant pressure limitation or also variable pressure limitation depending on different operating sizes As an alternative to the above-described high-pressure adjusting device with the valves 263, 264, a pressure-limiting device 270, 266, according to FIG. 8c, can also be used, according to which the feed pressure SP or control pressure enables different adjusting pressures depending on different operating parameters. The relevant pressure relief valve 266 is controlled via a corresponding signal 267 in such a way that the adjustment pressure enables two or more individual pressure stages or also a stepless pressure curve depending on various operating values or operating states. For example, an automatic pressure increase via the signals 267 or 271 or / and 259 can be triggered during the switching phase from one to the other switching range in order to effect a fast switching sequence. The devices 269 and 270 for increasing the control pressure can serve both for the adjustment pressure of the hydrostatic transmission and for the range switches for a brief pressure increase to accelerate the switching process. The initiation process of a range shift, for example the synchronous signal for the range shift or a signal from the accelerator pedal or accelerator pedal when the accelerator pedal is actuated quickly or depending on the actuation speed or the brake signal or other operating variable or operating signals suitable for a rapid pressure increase can be used as control signal 267 ; 271; 259 can be used for pressure boosting. During the switching phase 2V or 2R, the acceleration is continued continuously by simultaneously increasing the engine speed nMot. To optimize this functional sequence, a corresponding automatic influencing of the engine control for speed or / and torque increase or reduction, depending on the operating state - train, thrust or acceleration or deceleration - is additionally provided according to the invention.

This pressure boost is particularly advantageous for braking operation, in order to accelerate the reset speed of the transmission ratio and the range shifts and to enable a targeted adaptation to different operating situations.

Very fast switching from forward to reverse is of great importance for turning operation. In order to achieve a seamless transition from forward to reverse, the above-described devices for boosting the control pressure are also used for a quick clutch change. For reversing operation, the idling engine speed or the speed when the vehicle is stationary according to the operating phase 0 can be preprogrammed to a higher value in order to provide a higher starting power in this state from the start when the IFA pedal is released to have. After the starting function expires via the IFA or brake pedal, as described, after which A very rapid change in the gear ratio takes place or is intended to take place, it is provided that in the case of a power-split hydrostatic transmission with several shift ranges, the most spontaneous shift possible from 1 to 2 driving range, which means that while the brake or the IFA pedal is released, a very rapid switching from 1 to 2 switching range and possibly also to the 3 switching range can be carried out without having to operate the accelerator pedal. By deliberately automatically influencing the engine control by releasing the IFA pedal, it is very convenient and easy to operate, especially for demanding turning operations achieved in front loader or construction machine use This device is also particularly suitable for sensitive "inching" or "maneuvering" driving operations, since an additional inch pedal can be omitted instead of automatic engine control (via the so-called E-gas), can also a whom convenient manual gas actuation, e.g. by hand throttle

The automatic motor control or control of the motor control is preferably carried out in all functional sequences via the central control device 5 (processor), which includes or can include both the transmission control and the motor control. The control of the motor control takes place, as described, via respective actuation and Operating signals or operating variables, with the engine speed signal preferably forming the determining control variable If there is a deviation from a predetermined engine speed, a corresponding change in the engine control or throttle valve position and / or the transmission ratio l / i is effected in order to achieve the specified target values as precisely as possible to comply with all operating situations

The invention is further characterized in that the IFA pedal is assigned a translation characteristic which, depending on the pedal travel size or the pedal position, is assigned a transmission size of the transmission. When the pedal is fully depressed and corresponds to the pedal travel zero, the translation is l / i = Zero, corresponding to the stationary vehicle, the pedal airway (release path) is assigned a translation characteristic, which preferably has a progressive course depending on the airway size of the pedal. This means that in the starting state, there is initially a slight increase in the ratio l / i and against At the end of the airway there is a steeper increase in the translation. The course of the translation can be arbitrary, preferably curved or rectilinear in some areas. It is advantageous if the translation character is designed so that the last part of the airway is not assigned a fixed translation but, as in normal driving, the translation is free and any size depending on Lastrustand automatically brw to a desired translation. The vehicle speed can level off, which corresponds, for example, to the best consumption line or a pre-selected limit speed

The translation characteristic 'i described or shown in FIG. 8e can be a function of the actuating force and / or the release path of the IFA pedal. Another alternative of the function of the IFA pedal β provides that, depending on the release path and / or decreasing pedal force F, instead of the translation curve I / i, a speed curve Y or / and both functions depending on one or more operating partners. e.g. a load signal is specified or preprogrammed.

For normal operation, the invention provides that when the brake or IFA pedal is released, in particular by the brake pedal signal f, a gear change independent of the pedal travel or pedal force and thus speed change is possible, the brake pedal signal f affects the engine speed signal and overrides it to a correspondingly different extent, so that the desired speed is set. The brake pedal signal f also serves to reset the translation in braking operation as described in more detail in the above-mentioned known patent publication DE 44 17 335.

The invention further provides for the range shifts for upshifting as well as for downshifting, pulling or pushing shifting in combination with the shift correction already described or / and as an alternative to this a shift correction device, according to which the shift correction Gτöss Z over a tax correction time tk is determined. The adjustment correction time tk determines the size of the correction value or path Z in the switching instant or in the switching phase depending on the adjustment speed. The determining factor for this is therefore the control current or the delivery volume Qk. The effective control current Qk is determined by various at the time of switching effective variables such as feed pump delivery volume, speed, control pressure (constant or variable), internal throttling effects, oil temperature, etc. determined or influenced. The size of the adjustment speed or the adjustment current Qk can be determined experimentally, depending on the various operating states, engine speed, engine control signals such as throttle valve position, accelerator pedal position, oil temperature, etc. The control device or the electronics recognize which control correction time from these aforementioned values in which operating state is necessary for the "determination of the respective correction variable or the new displacement volume Vneu. For a precise determination of the correction time tk, the temperature, in particular oil temperature, oil viscosity and possibly further the volume flow of the £ 2

Control devices, leakage oil changes and factors influencing the switching time are also taken into account by appropriate signal processing in the control device. Also known eck _east lveränderungen in response to the operating time or / and load type and size of the program can be specified, whereby a suitably adapted increase or change of the correction (Z; k) is realized.

This switching correction device has the advantage that an expensive hydrostatic pressure sensor and in some cases also a hydrostatic displacement sensor (potentiometer) can be dispensed with. This method is suitable for both the area circuits and for the fixed-point circuits KB; KH; KD and also for reversing circuits, e.g. for service operation. Working machine - wheel loader, tractor front loader etc. -. Especially when using positive clutches with Ähweißverza nuxvg or friction clutches g "τ>, the opening signal is reduced very much before the torque is completely transferred from the old to the new clutch, ie before the end of the tax correction Z, since after the opening signal has been given, the relevant or The adjustment process of the hydrostatic transmission can thus largely be continued continuously even during the opening process of the aforementioned clutch, whereby a function overlap of the opening signal or the opening process of the named clutch and the hydrostatic adjustment is effective, whereby a Switching time reduction and high switching quality is achieved.

The system recognizes overrun, pull or cook downshifting in a simple manner from the respective engine speed and the throttle valve position or the size of the engine control, from which the correction direction of the hydrostatic adjustment device is determined: (see Fig. 7 and

7ab).

Supporting one or all of the above-mentioned shift correction devices, according to the invention, an additional influencing or lowering of the engine torque can also be used during the shift phase by automatic gas reduction, e.g. when using an electronic accelerator pedal in order to achieve optimum shift quality for the range, reversing and fixed point shifts in all operating situations.

Claims

1. Continuously variable transmission, in particular with hydrostatic power split, preferably for motor vehicles with preferably several switching ranges and / or with a device for hydrostatic bridging in the form of a fixed point circuit (KH, KB, KD), with a first hydrostatic unit (A) adjustable volume and one second hydrostatic unit (B), preferably of constant volume, with a summation planet to add up the hydraulic and mechanical power, in which the switching takes place without load interruption and / or without switching shock of the above-mentioned switching ranges or the fixed point circuits, the hydrostatic units (A) and (B) swap their function as a pump and motor when the range is changed and the range change occurs at synchronous speed of the clutch gears to be switched of the new clutch or the links for the fixed point shift and the old clutch or clutch of the fixed point shift (KH: KB: KD) only after adjustment ktur opens at a new displacement (Vneu), characterized in that the opening signal for the old clutch when changing range or clutch of the fixed point circuit (KH; KB: KD) from one or more torque-determining operating variables of the drive motor (M) (throttle valve position, accelerator pedal travel signal (a), engine control signal, speed signal (b), temperature signal, etc.) or that the opening signal is generated directly or indirectly from a drive with the Gearbox and / or the drive motor (M) operatively connected torque sensor is formed.

2 transmission according to the preamble of claim 1, characterized in that in the range shifts and / or fixed point shifts (KH; KB: KD) the shift correction size (Z) over a depending on the load condition of the engine and / or transmission correction time ( tk) is determined.

3. Gearbox according to claim 2, characterized in that in the range circuits and / or fixed point circuits, the shift correction size (Z) is determined via a correction - adjusting time (tk) or according to a pre-programmed time factor, so that the the shift correction (Z) required correction time (tk) is determined from the respective load state of the engine and / or transmission.

4. Transmission according to claim 1 d ad urch g eken n ze i c h n e t. that with a gearbox design with several different switching range sizes for each range switching point (1/2; 2/3; 3/4; or 4/3; 3/2; 2/1) and torque size »Tmot: Tan) a correspondingly adjusted adjustment correction or correction time (tk) or correspondingly adapted new displacement volume (Vneu) is assigned and preprogrammed to determine the opening signal of the old or relevant clutch, so that the adjustment correction size adapted to the respective load condition becomes effective for switching-shock-free operation. δ. Gearbox according to one or more of claims 1 to 4, characterized in that load or torque changes occurring during the shift phase (with the old and new clutch switched) are taken into account in such a way that the opening signal depends on the currently effective load state of the engine or / and gear or of the torque (Ta) is determined.

6. Transmission according to one or more of claims lbisδ characterized gekenn¬ characterized in that the each load state and each switching point (range switching; fixed point circuit) predetermined opening signal or predetermined new displacement volume (Vnew) undergoes a correspondingly adjusted correction depending on the current operating state or conditions within the switching phase (accelerator pedal change, speed of change, acceleration state, temperature etc.) or / and the type of clutch design (clutch factor fk, friction clutch, positive clutch) or / and depending.

7. Transmission according to one or more of claims 1 to 6, characterized in that the adjustment correction variable results from the size of the drive torque of the transmission (Tan), the torque (Tan) from one or more operating variables, in particular from operating variables of the drive motor (engine speed, Throttle valve position; control signal) and / or from secondary operating variables such as brake signal, manual adjustment signals, etc. is formed, where appropriate the adjustment correction size (tk; Z and others) is determined or calculated in the control / regulating device and / or that predetermined correction variables are corrected and adapted accordingly.

8. Hydrostatic-mechanical transmission with power split according to the preamble of claim 1, characterized in that for the fixed point circuit (KB: KH; KD) between the two working pressure lines (206 and 207) of the hydrostatic transmission (4c) Bypass valve (114c; 216) is switched, and a continuous automatic load-dependent adjustment correction or manipulated variable change of the hydrostatic transmission takes place within the fixed-point circuit via the shift correction device, whereby a new displacement or adjustment volume (Vnew) continuously corresponds to the switching state of the subsequent continuously variable switching range in each case corresponds to the given load state, is set, said bypass valve being activated or opened within the fixed point circuit (KB, KH; KD) and producing the short circuit between the two working pressure lines of the hydrostatic transmission, preferably the hydrostatic transmission adjustment within the fixed point circuit (KB, KH KD) is set or regulated in such a way that the working pressure lines (206, 207) have no or a predetermined low differential pressure and that when the fixed-point circuit is left, the bypass valve (114c.216) is first closed and i The old clutch (cl. K2) or clutch (KH KD) is opened in a no-load condition

9 gearbox according to one or more of claims lbisδ characterized gekenn¬ t that in the fixed point circuit and possibly missing bypass valve when leaving the fixed point circuit to initiate the new stepless switching range first a torque or load-dependent correction of the adjustment volume (Vneui triggered and then the opening signal to Open the corresponding old clutch (Kl or K2) or with fixed-point switching (KH or KD) when the relevant clutch is almost torque-free

10 gear according to one or more of claims lbιs9 gekenn¬ thereby drawing t. that within the fixed point circuit (KB, KH; KD) the bypass valve (114c, 216) in the open state maintains no differential pressure or maintains a low differential pressure between the two working pressure lines (206 and 207) of the hydrostatic transmission or / and that this differential pressure is dependent on operating signals, in particular load-dependent operating signals (a, b Tan) of the engine (M) and / or transmission can be vanated and that when the bypass \ entιls is closed there is a continuous build-up of pressure in the relevant working pressure line (206; 207) of the Hvdrostatgetπebes

11 gearbox according to claim 10 dad ek by n z e i c h n e t that the determining factors for determining the correction time (tk) and the new

Displacement (V new) one or more operating variables or operating signals such as accelerator pedal position, throttle valve position; Engine on control signal related to the current engine speed or comparable speed of the transmission, accelerator pedal change signal. Hydrostatic pressure signal of the hydrostatic circuit or other load signal, e.g. direct Torque signal, temperature u. if necessary, other influencing variables can be, the throttle valve position and the engine speed being particularly important for the load detection.

12. Transmission according to one or more of claims 1 to 11 thereby - zelch -net that a displacement volume sensor (displacement path; displacement angle sensor; electrical displacement current; vertical pressure) is provided, which measures the respective displacement volume, in particular (Vnew) and for the formation or Check the opening signal and / or the setting information, among other things can be effective.

13. Hydrostatic-mechanical power split, especially for motor vehicles with preferably several switching ranges, consisting of a stepless hydrostatic converter with a first hydrostatic unit A adjustable volume and a second hydrostatic unit B, preferably constant volume and a power split device in which the auxiliary power is divided into one hydraulic and a mechanical branch, which is summed up again in front of the transmission output, the stepless converter being driven by the drive shaft directly or via intermediate elements or intermediate stages and being in drive connection with a branching summation transmission, characterized in that an emergency drive device (80 ') is provided, which enables emergency operation in the event of failure of the central control and regulating device or the electronics (5) and / or the electrical system, such that a manually actuable control device g (80 '81') the hydrostatic adjustment (18) can be controlled and for an emergency operating area a continuous driving operation preferably works with power splitters that one or more clutches (KV, Kl or KR, Kl or Kl, K4 ) can be closed, in particular at zero travel speed, and establish a drive connection via a sum planet gear (251) between the input and output shafts of the transmission and the hydrostat gear (232), with a manual actuation device (lever 81 ': 108) Continuous operation from zero to the end of the switching range is mobile and that the couplings mentioned can preferably be controlled hydraulically via valves (W, VI or VR, VI or VI, V4).

14. Continuously variable transmission, in particular for motor vehicles, with an automatic drive for regulating the starting process, characterized in that the automatic start-up brings about the starting process via an inch accelerator pedal (IFA pedal) in the form of the brake pedal, with this pedal (7; 107) the start-up process is automatically triggered by a corresponding automatic gear change (l / i), with an automatic Activation of the engine control is effected in such a way that the throttle valve position or the engine controller is actuated as a function of the load state and / or of other operating variables or a predetermined engine speed characteristic (nMot I; nMot II) (FIG. 8a).

15. Gearbox according to one of claims 1 to 14, characterized in that an operating characteristic is preferably preselectable for the turning or reversing operation, such that an automatic or manual engine speed increase in the idling range and / or starting range is effective.

16. Transmission according to one of claims 14 to 15, characterized in that the IFA pedal (7; 107) causes the vehicle to stand still in the fully depressed state and when the pedal is released or released, a gear ratio assigned to the respective pedal position and / or driving speed is assigned.

17 transmission according to one of claims 14 to 16, characterized in that the IFA pedal travel is assigned a transmission characteristic of the transmission. which corresponds to a fixed gear ratio curve or gear line or a different or changeable gear ratio curve that is dependent on one or more operating parameters, or that the gear ratio assigned to the IFA pedal travel proceeds in such a way that a slight increase in gear ratio (1 / i increase) and counter-clockwise from zero driving speed At the end of the pedal travel there is a steeper increase in the gear ratio or that the gear ratio curve (l / i) has a progressive gear ratio or / and speed profile associated with the airway of the pedal

IS transmission according to one or more of claims 14 to 17, characterized in that the drive motor experiences an automatic influencing of the motor control depending on the IFA pedal and / or load-dependent, such that an automatic change in the motor control or The throttle valve position takes place so that, depending on the respective load condition, a different, appropriately adapted engine control variable is triggered, which corresponds to a favorable operating condition, in particular of the engine.

19. Transmission according to one of the preambles of the claims, characterized in that a device is provided which brings about an automatic increase in the control pressures for the hydrostatic adjustment and / or for the clutch shifting of the range clutches, such that the pressure valve is dependent on one or more operating parameters (266) is controlled via a corresponding signal (267), the control signal 267 ⁾ resulting from the accelerator pedal signal and / or a range switching signal (eg Synchronous signal for closing the new clutch) or / and a load signal (hydrostatic pressure) or / and the brake or ΣFA pedal signal (brake pedal signal f), or / and rate of change signal of the brake or IFA pedal signals f or / and other operation signals suitable for increasing the pressure.

20. Transmission according to one of claims, in particular claim 19, characterized in that the invention provides a device (269 according to Fig. 8b) for increasing the control pressure (valve 263), which switches the supply pressure (SP) to high pressure (HD) enables such that a control signal (259), the working pressure (HD) acts as a control pressure for the hydrostatic adjustment and / or for one or more of the range circuits of the transmission, an additional pressure relief valve (264) preferably permitting a maximum pressure limitation , whereby this pressure limitation can be a constant pressure or a variable pressure which is effective via a signal (271) and which can be influenced by different operating variables.

21. Transmission according to one or more of claims 1 to 20 characterized gekenn¬ characterized in that the shift correction device provides a function overlap of Off uDgs signal of the old clutch or clutch of the fixed point or reversing circuit and the hydrostatic adjustment signal, so that a largely continuation of the hydrostatic adjustment within the opening process of the aforementioned clutch is effective.