Hydrostatic traction drive, mobile working machine having the traction drive, and method for supplying data

Abstract

A hydrostatic traction drive for a mobile working machine includes a first hydraulic machine coupled to a drive machine, a second hydraulic machine arranged with the first hydraulic machine in a hydraulic circuit and coupled to an output, and an electronic control device. A characteristic diagram of a setpoint driving behavior of the mobile working machine is stored in the electronic control device and is parameterized at least in accordance with at least one driving request.

Claims

1. A hydrostatic traction drive for a mobile working machine, comprising: a first hydraulic machine coupled to a drive machine; a second hydraulic machine arranged with the first hydraulic machine in a hydraulic circuit and coupled to an output; and an electronic control device storing a characteristic diagram of a setpoint driving behavior of the mobile working machine, the stored characteristic diagram is dimensionless with respect to at least one characteristic of the mobile working machine, wherein the electronic control device is configured to generate a dimensioned setpoint value using the stored characteristic diagram and at least one driving request.

2. The traction drive according to claim 1, wherein the electronic control device is further configured to generate the dimensioned setpoint using a speed of the traction drive or of the mobile working machine.

3. The traction drive according to claim 1, wherein: the stored characteristic diagram of the setpoint driving behavior maps a setpoint traction force; and the at least one characteristic of the mobile working machine is a speed-dependent maximum traction force of the traction drive or of the mobile working machine.

4. The traction drive according to claim 1, wherein the at least one characteristic of the mobile working machine is stored in the electronic control device.

5. The traction drive according to claim 1, wherein the setpoint value is acquired from the stored characteristic diagram of the setpoint driving behavior by the electronic control device by multiplying the stored characteristic diagram with the at least one characteristic of the mobile working machine.

6. The traction drive according to claim 1, wherein the stored characteristic diagram of the setpoint driving behavior contains, at least for a speed equal to zero, a setpoint traction which is parameterized using the at least one driving request.

7. The traction drive according to claim 1, wherein the stored characteristic diagram of the setpoint driving behavior includes, for at least one loading force, a setpoint final speed which is parameterized using the at least one driving request.

8. The traction drive according to claim 1, wherein the stored characteristic diagram of the setpoint driving behavior includes a loading force sensitivity.

9. The traction drive according to claim 8, wherein the loading force sensitivity includes, for the at least one driving request, a speed change which is parameterized in accordance with a loading force change.

10. The traction drive according to claim 1, wherein the stored characteristic diagram of the setpoint driving behavior is stored after having been divided in a parameterized fashion into a plurality of driving ranges.

11. The traction drive according to claim 10, wherein the stored characteristic diagram of the setpoint driving behavior has, in each drive range of the driving ranges, a constant gradient with respect to the at least one driving request and/or a speed of the mobile working machine.

12. A mobile working machine, comprising: a hydrostatic traction drive including a first hydraulic machine coupled to a drive machine, a second hydraulic machine arranged with the first hydraulic machine in a hydraulic circuit and coupled to an output, and an electronic control device storing a characteristic diagram of a setpoint driving behavior of the mobile working machine, the stored characteristic diagram is dimensionless with respect to at least one characteristic of the mobile working machine, wherein the electronic control device is configured to generate a dimensioned setpoint using the stored characteristic diagram and at least one driving request.

13. A method for supplying data to an electronic control device of a hydrostatic traction drive for a mobile working machine, comprising: standardizing a characteristic diagram of a setpoint driving behavior of the mobile working machine such that the characteristic diagram is dimensionless with respect to at least one characteristic of the mobile working machine; storing the standardized characteristic diagram of the setpoint driving behavior in the electronic control device of the hydrostatic traction drive; and acquiring with the electronic control device a setpoint value of the setpoint driving behavior using the stored standardized characteristic diagram by multiplying the stored standardized characteristic diagram with the at least one characteristic of the mobile working machine.

14. The method according to claim 13, further comprising: transferring the setpoint driving behavior to another type of the traction drive or of the working machine or to another model of a same type of the working machine; and acquiring a further setpoint value for the other type of the traction drive or of the working machine or the other model of a same type of the working machine by multiplying the standardized characteristic diagram with at least one characteristic of the other type or of the other model, the at least one characteristic of the other type or of the other model is the same type characteristic as the at least one characteristic of the mobile working machine.

15. The method according to claim 13, further comprising: parameterizing the characteristic diagram using at least one driving request, and evaluating the standardized characteristic diagram using actual values of the at least one driving request and a speed, prior to acquiring the setpoint value of the setpoint driving behavior using the stored standardized characteristic diagram.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) In the drawings:

(2) FIG. 1 shows a schematic, hydraulic circuit diagram of a mobile working machine according to the disclosure,

(3) FIGS. 2, 3, 4 show a characteristic diagram of a setpoint driving behavior, parameterized in accordance with a speed and a driver's request, of the mobile working machine according to FIG. 1,

(4) FIG. 5 shows a block diagram of a first section of the method according to the disclosure for supplying data, in which section the characteristic diagram of a model or type of a mobile working machine is standardized,

(5) FIG. 6 shows a block diagram of a section of the method according to the disclosure for supplying data, in which section a control device of a second model of the mobile working machine according to FIG. 1 is supplied with data, and

(6) FIG. 7 shows the second model of the mobile working machine according to FIG. 1, activated with the setpoint traction force from the method according to FIG. 6.

DETAILED DESCRIPTION

(7) According to FIG. 1, a type of a mobile working machine 1 has the following design which remains constant over its possible model variants AMn: the working machine 1 has a hydrostatic transmission with a first hydraulic machine 2 which is configured as an axial piston pump of a swashplate design and with adjustable displacement volume, and a second hydraulic machine 4 which is configured as an axial piston motor of a swashplate design. The latter is also configured with adjustable displacement volume.

(8) Both hydraulic machines 2, 4 are fluidly connected in a closed hydraulic circuit via working lines 6, 8. In order to drive the first hydraulic machine 2, the latter is coupled to a drive machine 10 which is configured as diesel engine. The second hydraulic machine 4 is coupled to a differential 12 of an output axle 14 with two tires 16.

(9) In order to operate the hydrostatic traction drive and to transmit driver's requests, the mobile working machine 1 has a multiplicity of operator control elements. The latter are a travel direction switch 18, a brake pedal 20, an accelerator pedal 22, a driving mode selection switch 24, a speed-limiting switch 26 and 28, as well as a manual throttle 30. Moreover, a service interface 32 is provided.

(10) Furthermore, the mobile working machine 1 has an electronic control device 34 for controlling. Said control device 34 comprises a main control unit 36, an engine/motor control unit 38 of the driving machine 10 and a CAN bus 40 via which the operator control elements 18 to 30, the service interface 32 and the control device 34 are connected in a signal-transmitting fashion.

(11) The mobile working machine 1 can be of a different machine type. It can therefore be configured, for example, as a wheel loader, teleloader, stacker or the like. In this context, the described design is conceivable for different models of the type. The models can differ, in particular in respect of different power classes and/or speed ranges. That is to say they have, as a characteristic, for example a different maximum vehicle speed and/or maximum available power for the traction drive and/or maximum available traction drive traction force. These different properties or characteristics of the types or models of the mobile working machine 1 are allowed for according to the disclosure by means of type-specific and/or model-specific, standardized parameterization in the control device 34, which is explained in the text which follows.

(12) According to FIG. 1, the mobile working machine 1 has a rotational speed-sensing unit 42 via which a rotational speed n.sub.M of the second hydraulic machine 4 can be sensed and can be reported to the main control unit 36 via the CAN bus 40. In this context, parameters of the mobile working machine 1, to be more precise the specific type and model thereof are stored in the main control unit 36, by means of which parameters a speed v.sub.ist of the mobile working machine 1 can be acquired from the rotational speed n.sub.M. The specified parameters are, in particular, a transmission ratio of the differential 12 and circumferences of the wheels 16.

(13) The second hydraulic machine 4 also has an adjustment device 44 which is connected in a signal-transmitting fashion to the CAN bus 40 and via the latter to the main control unit 36. By means of said adjustment device 44, the main control unit 36 can control a pivoting angle α.sub.M, and therefore the displacement volume of the second hydraulic machine 4. The same applies to an adjustment device 46 of the first hydraulic machine 2 and the pivoting angle α.sub.p thereof. The mobile working machine 1 also has a pressure-sensor unit 48 by means of which a working pressure p in the working lines 6, 8 and/or a pressure difference Δp between the working lines 6, 8 can be sensed and transmitted to the CAN bus 40.

(14) FIGS. 2 to 4 show a non-standardized characteristic diagram F.sub.soll(α.sub.Ped,v.sub.ist) of a setpoint driving behavior of the mobile working machine 1 according to FIG. 1. FIG. 2 shows the entire characteristic diagram F.sub.soll(α.sub.Ped,v.sub.ist), wherein a setpoint traction force F.sub.soll is illustrated here, as a criterion for the setpoint driving behavior, in accordance with the speed v.sub.ist of the mobile working machine 1 and the driving request α.sub.Ped transmitted by the accelerator pedal 22, that is to say the pedal angle of said accelerator pedal 22. For different pedal angles α.sub.Ped, the profile of the setpoint traction force F.sub.soll is stored parameterized in accordance with the speed v.sub.ist. The parameterization produces the desired setpoint driving behavior. The upper three curves α.sub.Ped1 to α.sub.Ped3 according to FIG. 2 represent here a traction mode, and the curve illustrated underneath the v.sub.ist axle represents an overrun mode of the mobile working machine 1. In addition, an exemplary negative load F.sub.Last is included as a horizontal-dashed line. The profile of the setpoint traction force F.sub.soll is divided into driving regions, as a measure of a setpoint driving behavior for each pedal position α.sub.Ped. These driving regions are each characterized by a linear function with the gradient Δα.sub.Ped/Δv.sub.ist. This gradient Δα.sub.Ped/Δv.sub.ist represents, as a criterion of the setpoint driving behavior, a so-called load sensitivity, that is to say a relationship between a loading force change and a speed change resulting therefrom.

(15) FIG. 3 shows, as a criterion for the setpoint driving behavior, a force buildup of the setpoint traction force F.sub.soll in accordance with the position of the accelerator pedal α.sub.Ped, and specifically for a speed of v.sub.ist=0. This case is given, for example, if a towing working machine is to tow a heavy vehicle. The steeper the force buildup here the greater the risk of a cable rupture. In order to avoid such a case, according to FIG. 3 the setpoint traction force F.sub.soll initially rises only very gently to the right with a rising accelerator pedal angle α.sub.Ped.

(16) FIG. 4 shows, as a criterion for the setpoint driving behavior, a rise in the maximum or steady-state speed v.sub.stat, occurring in the force equilibrium F.sub.soll=F.sub.zug=F.sub.Last, in accordance with the accelerator pedal angle α.sub.Ped.

(17) As already mentioned, both diagrams in FIGS. 3 and 4 are contained in the characteristic diagram F.sub.soll(v.sub.ist,α.sub.Ped) according to FIG. 2.

(18) FIG. 5 shows a block diagram of an exemplary embodiment of a method 50 for supplying data, wherein initially a first section 50a of the method is illustrated in which standardization of the already mentioned characteristic diagram takes place by means of characteristics of a first type and model, indicated by AM1, of the mobile working machine 1.

(19) FIG. 6 then describes the following section 50b of the method in which the setpoint driving behavior, which is described via the abovementioned standardized characteristic diagram, is transferred onto a second model, indicated by AM2, of the same type of the mobile working machine 1.

(20) The standardization section 50a of the method according to FIG. 5 is preferably stored in a computing and/or storage unit which is provided “offboard” of the mobile working machine, for example for use within a development process of a development division, for implementation. Alternatively or additionally, each section of the method 50 can, of course, be stored in the electronic control device 34 or another control unit of the mobile working machine 1.

(21) According to FIG. 5, the characteristic diagram of the setpoint traction force F.sub.Soll,AM1 is selected for the description of the setpoint driving behavior of the first model and type AM1 of the working machine 1, which setpoint traction force F.sub.Soll,AM1, is, according to method step 52, parameterized in such a way that it can be derived from the rotational speed n.sub.M of the second hydraulic machine 4 in accordance with the driving request α.sub.Ped,AM1 and the speed v.sub.AM1. The maximum achievable speed v.sub.ref,AM1 of the first model and type AM1 is input into the method as fixed characteristic thereof. By division by v.sub.ref,AM1, the standardization of the speed variable v.sub.AM1 is carried out in the method step 53 so that the speed axis v.sub.AM1/v.sub.ref,AM1 of the setpoint traction force F.sub.Soll,AM1,vnorm which is represented in this way is dimensionless. According to a method step 54, a suitable characteristic is selected as a reference for the setpoint traction force F.sub.Soll,AM1,vnorm—In the exemplary embodiment shown this is a reference force F.sub.ref,AM1 which is described as a function of the variable speed v.sub.AM1. For example, the function of a maximum achievable traction force F.sub.max(v.sub.AM1) of the first model and type AM1 of the working machine 1 is suitable as a reference force. In step 56, as already for the setpoint traction force, the variable v.sub.AM1 is also standardized to the fixed characteristic v.sub.ref,AM1 for the reference force F.sub.ref,AM1. Therefore, the characteristic F.sub.ref,AM1,vnorm is then also described and stored in accordance with the standardized variable v.sub.AM1/v.sub.ref,AM1. In the next step 58, a standardized characteristic diagram K(α.sub.Ped,AM1, v.sub.AM1/v.sub.ref,AM1) is produced by referring the characteristic diagram F.sub.Soll,AM1,vnorm to the characteristic F.sub.ref,AM1,vnorm. In a general type-independent and model-independent notation there results from this in step 59 according to FIG. 5 the standardized characteristic diagram K(α,x) which is the basis for the following section 50b of the method according to the disclosure according to FIG. 6 in which the setpoint driving behavior of the first model AM1 of the working machine 1 is transferred onto a second model AM2 of the same type of the working machine 1 and is used to control the traction drive.

(22) This following section is preferably stored in the control device 34 of the model AM2 of the mobile working machine 1, that is to say the “onboard”, for implementation.

(23) According to FIG. 6 input variables of this following step of the method are: the standardized characteristic diagram K(α,x), the characteristics v.sub.ref,AM2 and F.sub.ref,AM2(v.sub.AM2) of the model AM2 and the variables α.sub.ped,AM2 and v.sub.AM2 which have been sensed and/or acquired in the driving mode of this model. In the driving mode of the model AM2 of the mobile driving machine 1, the electronic control device 34 continuously acquires the actual speed v.sub.ist,AM2 from the rotational speed n.sub.M. At the same time, it obtains the driver's driving request α.sub.Ped,ist,AM2 as a specification of said driver. With these inputs and with knowledge of the characteristics v.sub.ref,AM2 and F.sub.ref,AM2 of the model AM2 it determines the actual setpoint traction force F.sub.soll,AM2(α.sub.Ped,ist,AM2,v.sub.ist,AM2). Initially, for this purpose in step 60a the standardized actual speed is determined by dividing v.sub.ist,AM2 by the fixed characteristic v.sub.ref,AM2. Subsequently, in step 60b, the standardized characteristic diagram K(α,x) is evaluated for the actual driver accelerator pedal position α=α.sub.ped,ist,AM2 and the standardized actual speed x=v.sub.ist,AM2/v.sub.ref,AM2. In step 60c, the value of the characteristic F.sub.ref,AM2(v.sub.AM2) is evaluated for the actual speed v.sub.ist,AM2. In the step 60d, according to FIG. 6 the actual dimensioned setpoint traction force F.sub.soll,AM2 is acquired for the sensed actual values α.sub.ped,ist,AM2 and v.sub.ist,AM2 by operating (multiplying) with the characteristic diagram evaluated in step 60b, with the characteristic diagram K which is evaluated in step 60b.

(24) This setpoint value F.sub.soll,AM2(α.sub.ped,ist,AM2,v.sub.ist,AM2) is input into a downstream controller 62 according to FIG. 7 by means of which—depending on the stored control strategy—setpoint values α.sub.Msoll, α.sub.Psoll and M.sub.soll, n.sub.soll are transmitted to the machines 2, 4 and 10. One of the two values, the setpoint torque M.sub.soll or preferably setpoint rotational speed n.sub.soll, is transmitted here to the engine control unit 38 of the drive machine 10.

(25) A hydrostatic traction drive is disclosed having a control device in which a setpoint driving behavior of the traction drive or of a mobile working machine for which this traction drive is provided is stored in a parameterized fashion. According to the disclosure, the setpoint driving behavior is stored, referred to a property or a, in particular fixed, characteristic of a type or of a model of the traction drive or of the drive machine, and as a result standardized.

(26) Furthermore, a mobile working machine with such a hydrostatic traction drive is disclosed.

(27) A method for supplying data to the control device is also disclosed, said method containing at least one of the steps of standardizing the setpoint driving behavior by means of the at least one, in particular fixed, characteristic, storing the standardized setpoint driving behavior or acquiring a setpoint value of the setpoint driving behavior from the standardized setpoint driving behavior by operating with (e.g. by multiplying by) the at least one, in particular fixed, characteristic.