Hydraulic pressurizing medium supply assembly, method, and mobile work machine

Abstract

A hydraulic pressurizing medium supply assembly having a hydro machine for supplying pressurizing medium of at least one hydraulic consumer, includes a hydraulic control block for controlling the at least one consumer, a first control module, and a second control module. The control block, by way of the first control module, is able to be controlled by at least one actuating signal. A data interface is included between the control modules. The first control module, by way of the data interface, as a further actuating signal transfers to the second control module as input variable/variables a nominal outlet pressure for the hydro machine and/or a nominal delivery volume for the hydro machine. The second control module by way of the nominal outlet pressure and/or by way of the nominal delivery volume controls an adjusting mechanism of the hydro machine by way of a valve actuating signal.

Claims

1. A hydraulic pressurizing medium supply assembly, comprising: a hydro machine configured to supply pressurizing medium to at least one hydraulic consumer; an adjusting mechanism operably connected to the hydro machine; a hydraulic control block configured to control the at least one hydraulic consumer; a first control module operably connected to the hydraulic control block and configured to generate at least one actuating signal for controlling the hydraulic control block; a second control module operably connected to the adjusting mechanism; and a data interface operably connected to the first and the second control modules, wherein the data interface is configured to transfer a further actuating signal from the first control module to the second control module as at least one input variable, wherein the at least one input variable corresponds to a nominal outlet pressure for the hydro machine and/or a nominal delivery volume for the hydro machine, wherein the second control module is configured (i) to generate a valve actuating signal based on the at least one input variable, and (ii) to control the adjusting mechanism based on the valve actuating signal, and wherein the at least one input variable includes at least one hydraulic parameter which predefines and/or limits a dynamic characteristic of the adjusting mechanism.

2. The hydraulic pressurizing medium supply assembly according to claim 1, wherein the at least one hydraulic parameter includes a maximum gradient of one or a plurality of actual variable/variables of the hydraulic pressurizing medium supply assembly.

3. The hydraulic pressurizing medium supply assembly according to claim 1, wherein the at least one hydraulic parameter includes at least one of a maximum delivery-volume adjustment rate of the hydro machine, a maximum pressure gradient for an actual outlet pressure of the hydro machine, a maximum nominal differential pressure for the hydro machine, and a maximum torque gradient.

4. The hydraulic pressurizing medium supply assembly according to claim 3, wherein adapting the maximum nominal differential pressure takes place in such a manner that the maximum nominal differential pressure is included for a normal operation of the pressurizing medium supply assembly, and/or that the maximum nominal differential pressure is included for a precision-control range of at least one of the hydraulic consumers, and/or that a maximum nominal differential pressure is included in a general control range of the at least one hydraulic consumer.

5. The hydraulic pressurizing medium supply assembly according to claim 3, wherein: various operating modes are able to be set, the various operating modes include at least one pre-set parameter and/or one pre-set actuating signal for the dynamic characteristic of the adjusting mechanism of the hydro machine, and the various operating modes differ from one another in terms of at least one parameter and/or in terms of the at least one actuating signal.

6. The hydraulic pressurizing medium supply assembly according to claim 5, wherein: adapting a pressure gradient and/or a swivel angle gradient as one of the operating modes takes place as a function of the at least one hydraulic consumer which is being moved, adapting of the maximum pressure gradient as one of the operating modes takes place as a function of a deflection of at least one operating element, adapting the at least one hydraulic parameter as one of the operating modes takes place when a specific operating or actuating situation is detected, and/or adapting a torque limit as one of the operating modes takes place as a function of an operating state of an electric drive.

7. The hydraulic pressurizing medium supply assembly according to claim 1, wherein the data interface is configured to supply a nominal torque as the further actuating signal for the second control module.

8. The hydraulic pressurizing medium supply assembly according to claim 1, wherein the at least one hydraulic parameter is set as a function of at least one of a temperature of the pressurizing medium, an actual rotating speed of the hydro machine, an actual outlet pressure of the hydro machine, and an actual delivery volume of the hydro machine.

9. The hydraulic pressurizing medium supply assembly according to claim 1, further comprising: at least one filter for the at least one input variable to the second control module, wherein the at least one filter provides a PT1 transfer function.

10. The hydraulic pressuring medium supply assembly according to claim 1, wherein a mobile work machine includes the hydraulic pressurizing medium supply assembly.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

(1) Preferred exemplary embodiments of the disclosure will be explained in more detail hereunder by means of schematic drawings, in which:

(2) FIG. 1 in a schematic illustration shows a hydraulic pressurizing medium supply assembly according to a first exemplary embodiment;

(3) FIG. 2 in a schematic illustration shows a second control module for the pressurizing medium supply assembly from FIG. 1;

(4) FIG. 3 in a schematic illustration shows a second control module for the pressurizing medium supply assembly from FIG. 1 according to a further exemplary embodiment;

(5) FIG. 4 in a schematic illustration shows a pressurizing medium supply assembly for a mobile work machine, according to a first exemplary embodiment;

(6) FIG. 5 in a schematic illustration shows a pressurizing medium supply assembly for a mobile work machine, according to a further exemplary embodiment.

DETAILED DESCRIPTION

(7) Shown according to FIG. 1 is a hydraulic pressurizing medium supply assembly 1 which has a hydro machine in the form of an axial piston machine 2. Said axial piston machine 2 has a swivel cradle for adjusting a delivery volume. The axial piston machine 2 can be used as a pump as well as a motor. The axial piston machine 2 is driven by a drive unit 4 which can be, for example, an internal combustion engine such as, for example, a diesel engine, or an electric motor. The axial piston machine 2 is connected to the drive unit 4 by way of a drive shaft 6. A rotating speed 8 of the drive shaft 6 can be detected by way of means not illustrated, for example by way of a speed sensor, and be supplied to a control of the pressurizing medium supply assembly 1. An adjusting mechanism 12 is provided for the axial piston machine 2. Said adjusting mechanism 12 has a pilot valve 14. The valve slide of said pilot valve 14 is electrically actuatable in a proportional manner by way of an actuator 16. To this end, the actuator 16 is supplied a control variable 18 by a second control module 20. The valve slide of the pilot valve 14 in the direction of an initial position is impinged with a spring force of a valve spring 22. The spring force acts counter to the actuating force of the actuator 16.

(8) The axial piston machine 2 at the outlet side is connected to a pressure line 24 which in turn is connected to a main control valve 26 or a valve block. The supply of pressurizing medium between the axial piston machine 2 and one or a plurality of consumers can be controlled by way of said main control valve 26. A control line 28 which is connected to a pressure connector P of the pilot valve 14 branches off from the pressure line 24. An internal supply of the axial piston machine 2 herein can be guaranteed by a corresponding construction. The control line 28 is configured, for example, in a housing of the axial piston machine 2. The pilot valve 14 furthermore has a tank connector T which by way of a tank line 30 is connected to a tank. The pilot valve 14 moreover has an operation connector A which is connected to a control chamber 32 of an actuating cylinder 34. The control chamber 32 herein is delimited by a set piston 36 of the actuating cylinder. A swash plate of the axial piston machine 2 can in this instance be adjusted by way of the set piston 36. A displacement path of the set piston 36 is detected by a displacement transducer 38. Alternatively or additionally, a swivel angle of the swivel cradle of the axial piston machine 2 is detected on a swivel axle of the swivel cradle by way of a rotary magnetic sensor. The actual delivery volume or the actual displacement volume of the axial piston machine 2 can in this instance be determined by way of the detected path. The actual delivery volume 40 is then reported to the control 20. The pressure connector P in the initial position of the valve slide of the pilot valve 14 is connected to the operation connector A, and the tank connector T is blocked. When the valve slide is impinged with the actuating force of the actuator 16, the valve slide, proceeding from the initial position thereof, is moved in the direction of switched positions in which the pressure connector P is blocked and the operation connector A is connected to the tank connector T. The set piston 36 in the initial position of the valve slide of the pilot valve 14 is thus impinged with pressurizing medium from the pressure line 24. Furthermore provided in the adjusting mechanism 12 is a cylinder 42. The latter has a set piston 44 which engages on the swash plate of the axial piston machine 2. The set piston 44 limits a control chamber 46 which is connected to the pressure line 24. The set piston 44 by way of pressurizing medium of the control chamber 46 and by way of the spring force of the spring 48 is impinged in such a manner that said set piston 44 loads the swash plate in the direction of increasing the delivery volume.

(9) Furthermore provided is a pressure sensor 50 by way of which the pressure in the pressure line 24 is detected and reported to the second control module 20, wherein the pressure is an actual outlet pressure 52. Moreover provided is a pressure sensor 54 which detects the highest actual load pressure (actual LS pressure) 56, the latter being transmitted to the second control module 20.

(10) A first control module 57 by way of a CAN interface 58 is connected to the second control module 20, in particular for transmitting the actual rotating speed 8 to the second control module 20. It is also conceivable for the actual rotating speed 8 to be supplied directly to the second control module 20.

(11) The position of the swash plate of the axial piston machine 2 in the use of the pressurizing medium supply assembly 1 is controlled by way of the pilot valve 14 and the set piston 36. A conveyed volumetric flow of the axial piston machine 2 is proportional to the position of the swash plate. The set piston 44 pre-loaded by the spring 48, or the counter piston, is at all times impinged by the actual outlet pressure or the pump pressure. In a non-rotating axial piston machine 2 and an adjusting mechanism 12 without pressure the swash plate by the spring 48 is kept in a position of +100 percent. In a driven axial piston machine 2 and a non-energized actuator 16 of the pilot valve 14, the swash plate pivots to a zero-stroke pressure, since the set piston 36 is impinged with pressurizing medium of the pressure line 24. Equilibrium between an actual outlet pressure at the set piston 36 and the spring force of the spring 48 is established at a predetermined pressure or pressure range, for example between 8 to 12 bar. Said zero-stroke operation is assumed, for example, in the event of de-energized electronics or a de-energized second control module 20. The actuation of the pilot valve 14 takes place by way of the second control module 20, the latter being, for example, preferably digital electronics, alternatively analog electronics. The second control module 20 processes the required control signals, as is explained in more detail hereunder.

(12) For example, a nominal delivery volume 70 or a nominal swivel angle or a maximum nominal pressure gradient 102 and/or a nominal pressure differential 100 and/or a nominal torque 116 and/or a maximum nominal delivery-volume adjustment rate 130 and/or a nominal outlet pressure 74 can be supplied from the first control module 57 to the second control module 20 by way of the data interface 58. It is furthermore conceivable for an actual delivery volume 40 or an actual swivel angle and/or an actual LS pressure 56 and/or an actual outlet pressure 52 and/or an actual torque 124 to be supplied from the second control module 20 to the first control module 57. The variables 40, 56, 52 and/or 124 herein are preferably filtered.

(13) FIG. 2 schematically shows a functioning mode of the second control module 20. The latter has a first closed-loop control circuit 60 and a second closed-loop control circuit 62. The first closed-loop control circuit 60 has a controller 64 for a swivel angle of the swash plate of the axial piston machine 2 from FIG. 1, a controller 66 for the outlet pressure of the axial piston machine 2, and a controller 68 for a torque of the axial piston machine 2. The controller 64 as input variables has a nominal delivery volume 70 and the actual delivery volume 40. A control variable 72 is provided as an output variable. The controller 66 as input variables has a nominal outlet pressure 74 and the actual outlet pressure 52. A control variable 75 is provided as an output variable. The controller 68 as input variables has an actual torque 76 or a nominal torque. The actual torque which in turn is able to be determined, for example, by means of a characteristics map by way of the actual rotating speed 8 is provided as a further input variable. A control variable 78 is provided as an output variable for the controller 68. In the respective controller 64 to 68, the input variables are in each case supplied to a control element in the form of a PID controller.

(14) The control variables 72, 75 and 78 are supplied to a minimum value generator 80. The latter ensures that only the controller 72, 75 or 78 assigned to the desired operating point is automatically active. Either the outlet pressure, the torque, or the delivery volume herein is precisely controlled, wherein the respective two other variables are below a predefined nominal value. An output signal of the minimum value generator 80 in this instance is a nominal value in the form of a delivery-volume adjustment rate or a nominal delivery-volume adjustment rate 82. The latter in this instance is an input variable for the second subordinate closed-loop control circuit 62. The derivation of the actual delivery volume 40 is a further input variable of the second closed-loop control circuit 62, said further input variable in this instance being an actual delivery-volume adjustment rate 84. The input variables 82 and 84 for the second closed-loop control circuit 62 are then supplied to a control element in the form of a PID element 86. The latter then emits the control variable 18 for the pilot valve 14 from FIG. 1.

(15) According to FIG. 3, a further embodiment for the second control module 20 from FIG. 1 is shown. Said further embodiment has a controller 88 for the delivery volume of the axial piston machine 2, cf. also FIG. 1. Furthermore provided are a controller 90 for the outlet pressure of the axial piston machine 2 and a controller 92 for the torque of the axial piston machine 2. This forms part of a first closed-loop control circuit 94. Furthermore provided so as to underlie the first closed-loop control circuit is a second closed-loop control circuit 96 for the delivery-volume adjustment rate of the axial piston machine 2.

(16) The controller 88 has a control element 98 in the form of a P-element. The nominal delivery volume 70 and the actual delivery volume 40 are provided as input variables. The actual delivery volume 40 is supplied to the control element 98 by way of a filter in the form of a PT1 filter. The control variable 72 is provided as the output variable at the output side of the controller 88, said control variable 72 being supplied to the minimum value generator 80.

(17) The controller 90 as input variables has the actual outlet pressure 52, the actual LS pressure 56, a nominal pressure differential 100 and a nominal pressure gradient 102. The actual LS pressure 56 and the nominal pressure differential 100 by way of a summing element 104 are linked so as to form a nominal outlet pressure. The nominal outlet pressure is then supplied to a control element 106 in the form of an inverted PT1 element which estimates a predicted signal profile. The nominal outlet pressure is then furthermore supplied to a control element 108 which has the nominal pressure gradient 102 as a further input variable. The nominal pressure gradient 102 then predefines the maximum potential gradient which is to be provided. The nominal outlet pressure by way of the control element 108 is then influenced by the predefined nominal pressure gradient 102 in such a manner that the dynamic characteristic of the pressurizing medium supply assembly 1 from FIG. 1 can be controlled by the nominal pressure gradient 102. For example, the influence can be such that the higher the nominal pressure gradient 102 the more rapidly the swash plate of the axial piston machine 2 is able to be adjusted. It conversely applies in this instance that the smaller the nominal pressure gradient the slower the swash plate of the axial piston machine 2 is adjusted. After the control element 108, the nominal outlet pressure is then supplied to a control element 110 in the form of a PID element. The actual outlet pressure 52 is then provided as a further input variable for the control element 110. The control variable 75 which is supplied to the minimum value generator 80 results as the output variable of the control element 110.

(18) The actual LS pressure 56 of the controller 90 prior to the summing element 104 is supplied to a filter 112 which is a variable PT1 filter. The same applies to the actual outlet pressure which prior to the control element 110 is likewise supplied to a filter 114 in the form of a variable PT1 filter. The filters 112 and 114 have variable, in particular pressure-dependent, filter coefficients, as is explained in more detail above.

(19) The controller 92 as input variables has the actual rotating speed 8, the actual delivery volume 40, the actual outlet pressure 52, and a nominal torque 116. The input variables are supplied to a control element 118 in the form of a P-element. The control variable 78 which is supplied to the minimum value generator 80 is provided as an output variable for the control element 118. A control element 120 which, as in the case of the control element 106, is an inverted PT1 filter is provided for the control variable 78 after the control element 118. Furthermore, the actual rotating speed, the actual delivery volume 40, and the actual outlet pressure 8, prior to being supplied to the control element 118, are supplied to a control element 122. The latter serves for calculating an actual torque 124 based on the actual rotating speed 8, on the actual delivery volume 40, and the actual outlet pressure 8. The calculation is performed by means of a characteristics map of the control element 122. The characteristics map is a function of the actual outlet pressure 52 which is supplied to the control element 122. The actual delivery volume 40 is furthermore supplied to the control element 122. The characteristics map in this instance can alternatively or additionally be a function of the actual delivery volume 40. In other words, the actual torque 124 is formed from the actual rotating speed 8 and from the actual outlet pressure 52 and/or from the actual delivery volume 40. The actual torque 124, prior to reaching the control element 118, is then subsequently supplied to a filter 126 in the form of a PT1 element.

(20) Furthermore, the actual delivery volume 40, prior to being supplied to the control element 98, is supplied to a filter 99 in the form of a PT1 element.

(21) The minimum value generator 80 from the control variables 72, 75 and 78 forms the nominal delivery-volume adjustment rate 82. The latter is supplied to a control element 128. The dynamic characteristic of the pressurizing medium supply assembly 1 can be influenced by said control element 128. To this end, a delivery-volume adjustment rate target 130, which is adjustable, is provided as a further input variable for the control element 128. For example, the nominal delivery-volume adjustment rate 82 which is emitted from the minimum value generator 80 can be limited and/or influenced in such a manner by way of the delivery-volume adjustment rate target 130 that the greater the variable 130 the faster the swash plate of the axial piston machine 2 can be pivoted and vice versa. The dynamic characteristic of the pressurizing medium supply assembly 1 can thus be influenced by adjusting the delivery-volume adjustment rate target 130 and/or by adjusting the nominal pressure gradient 102. On account thereof, the pressurizing medium supply assembly 1 can be adapted in a simple and cost-effective manner to different work machines and/or to different application conditions and/or to different specific applications, for example.

(22) After the control element 128, the final nominal delivery-volume adjustment rate 132 as an input variable is supplied to the second closed-loop control circuit 96. The latter has a control element 134 in the form of a PI-element. The actual delivery-volume adjustment rate 84 is provided as a further input variable for the control element 134. Said actual delivery-volume adjustment rate 84 is based on the actual delivery volume 40 which is derived in a control element 136. Thereafter, the derivation, thus the actual delivery-volume adjustment rate, is supplied to a filter 138 in the form of a PT1 filter. Prior to the actual variable 84 being supplied to the control element 134, a control element 140 in the form of an inverted PT1 filter is subsequently provided. The control element 134 of the second closed-loop control circuit 96 has the control variable 18 as the output variable for the pilot valve 14 from FIG. 1. Said control variable 18 is supplied to a summing element 142. A preliminary control value 144 is provided as a further input variable for the summing element 142. Said preliminary control value 144 is an output variable of a control element 150 which has the actual outlet pressure 52 as the input variable. The preliminary control value 144 is then determined based on the actual outlet pressure 52. The summing element 142 then links the control variable 18 and the preliminary control value 144, a neutral current of the pilot valve being pre-controlled therewith. A pressure-dependent target of a neutral signal value for the pilot valve 14 from FIG. 1 is thus established. This has the advantage that the control 20 is relieved in terms of said control task. A final control variable 146 for the pilot valve 14 is then provided as an output variable of the summing element 142.

(23) It is conceivable that a control element which is not illustrated in FIG. 3 and which has the control variable 146 as the input variable is disposed downstream of the summing element 142. Said control variable 146 is superimposed with a high-frequency signal by the control element, so that the valve slide of the pilot valve 14 is continually in axial oscillating movement so as to avoid seizing of the valve slide. The final control variable for the pilot valve 14 is in this instance provided as the output variable of the control element. The superimposition by the high-frequency signal can be referred to as “dithering”.

(24) According to FIG. 3, the actual delivery volume 40 after the filter 99, as a filtered actual delivery volume 152, can be supplied to the first control module 57 from FIG. 1. Furthermore, the actual LS pressure after the filter 112, as a filtered actual LS pressure 154, can be supplied to the first control module 57 from FIG. 1. The actual outlet pressure 52 after the filter 114, as a filtered actual outlet pressure 156, can likewise be supplied to the first control module 57. Moreover, the actual torque 124 after the filter 126, as a filtered actual torque 158, can be supplied to the first control module 57.

(25) FIG. 4 shows the pressurizing medium supply assembly for a mobile work machine in the form of a telehandler. Said telehandler has two axial piston machines 2 and 186 which by the drive unit 4 in the form of a diesel engine are driven by way of a common drive shaft. Pilot valves of the axial piston machine 2, 186 are controlled by way of the control 20, as has been explained above. The axial piston machine 186 serves for supplying pressurizing medium to a wheel brake 188, to a steering system 190, and to a pilot fluid supply 192. The pilot fluid supply 192 is provided for the main control valve 26, or the main control valve block, respectively. The supply of pressurizing medium to hydro cylinders 168, 170, 194, 196 is controlled by way of said main control valve block. A hydro machine 198 used and the hydraulic auxiliary motor 176 are furthermore controlled by way of the main control valve 26. Input means 178 which by way of the CAN bus 180 are connected to the second control module 20, for example, are provided. A communication installation 200 and is furthermore provided in order to communicate with a server and/or with a computer in a wireless manner, for example by radio or WiFi. For example, input variables for the second control module 20 can in this instance be adapted by way of the communication installation 200 and/or a software can be upgraded or updated by way of the communication installation 200. Moreover, it is possible for data which includes information pertaining to a state of the pressurizing medium supply assembly 1 to be sent by way of the communication installation 200. The control modules 20 and 57 according to FIG. 4 are disposed in a common housing. The data interface by way of which the variables 70, 102, 100, 116, 130, 74, 40, 56, 52 and 124 can be transmitted is provided within the housing.

(26) According to FIG. 5, a pressurizing medium supply assembly for a compact excavator is shown. The axial piston machine 2 which is driven by the drive unit 4 in the form of a diesel engine can be seen herein. Furthermore shown is the second control module 20 which is connected to a pressure sensor 202, for example, which detects the actual outlet pressure of the axial piston machine 2. The second control module 20 is moreover connected to a pressure sensor 204 which by way of the main control valve 26, or the main control block, respectively, detects the highest load pressure. The second control module 20 is furthermore connected to a sensor 206 for the swivel angle of the swash plate of the axial piston machine 2. The pilot valve 14 is moreover connected to the second control module 20. Five hydro cylinders 208 are connected to the main control valve 26. Furthermore connected are the hydro machines 172, 174, and the hydraulic auxiliary motor 176. The pilot fluid supply 192 can optionally be provided. Input means 178 can hydraulically control the main control valve 26, for example, or be connected to the pressurizing medium supply assembly by way of the CAN bus 180. Apart from the second control module 20, the first control module 57 is furthermore shown. The variables 70, 102, 100, 116, 130, 74, 40, 56, 52 and/or 124 can in this instance be exchanged by way of the data interface in the form of the CAN bus.