HYDRAULIC ARRANGEMENT AND UTILITY VEHICLE

Abstract

A hydraulic arrangement for a utility vehicle. In one implementation, the arrangement may include a hydraulic displacement pump and a supply connection as an interface for supplying hydraulic consumers, a displacement control unit dependent on an output pressure of the displacement pump for displacing the displacement pump, a hydraulic auxiliary pump and an auxiliary supply connection as an interface for alternatively supplying at least some of the consumers, and a hydraulic valve unit hydraulically arranged in a throughflow path between a pump output of the displacement pump and the supply connection. The hydraulic valve unit may have a first switching position in which the pump output is hydraulically connected to the supply connection and hydraulically separated from an output of the auxiliary pump, and a second switching position in which the pump output is hydraulically separated from the supply connection and hydraulically connected to the output of the auxiliary pump.

Claims

1. A hydraulic arrangement for a utility vehicle, the hydraulic arrangement comprising: a hydraulic displacement pump and a supply connection as an interface for supplying hydraulic consumers of the utility vehicle; a displacement control unit which is dependent on an output pressure of the displacement pump for displacing the displacement pump; a hydraulic auxiliary pump and an auxiliary supply connection as an interface for alternatively supplying at least some of the consumers; and a hydraulic valve unit which is hydraulically arranged in a throughflow path between a pump output of the displacement pump and the supply connection; wherein the hydraulic valve unit has a first switching position in which the pump output of the displacement pump is hydraulically connected to the supply connection and hydraulically separated from an output of the auxiliary pump, and a second switching position, in which the pump output of the displacement pump is hydraulically separated from the supply connection and hydraulically connected to the output of the auxiliary pump.

2. The hydraulic arrangement of claim 1, wherein the valve unit is in the second switching position thereof with the displacement pump being stopped and the auxiliary pump being driven.

3. The hydraulic arrangement of claim 2, wherein the hydraulic arrangement has at least one of the following features with an increasing output pressure at the pump output of the displacement pump after reaching or exceeding a predetermined desired pressure: the valve unit is in a different switching position from the second switching position; the drive of the auxiliary pump is reduced or deactivated; and the displacement pump is driven.

4. The hydraulic arrangement of claim 1, wherein the valve unit has a separation switching position, in which the pump output of the displacement pump is hydraulically separated from the supply connection and the output of the auxiliary pump.

5. The hydraulic arrangement of claim 4, wherein the valve unit, after reaching or exceeding a predetermined desired pressure at the pump output of the displacement pump, takes up the separation switching position.

6. The hydraulic arrangement of claim 5, wherein the valve unit takes up the first switching position after the separation switching position.

7. The hydraulic arrangement of claim 1, wherein in an auxiliary throughflow path between the output of the auxiliary pump and the auxiliary supply connection is a hydraulic auxiliary valve unit having a plurality of switching positions, wherein in a first switching position of the plurality of switching positions, the output of the auxiliary pump is hydraulically connected to the auxiliary supply connection, and in a second switching position of the plurality of switching positions, the output of the auxiliary pump is hydraulically separated from the auxiliary supply connection.

8. The hydraulic arrangement of claim 1, wherein at least one of the valve unit or the auxiliary valve unit is at least one of the following: in the second switching position thereof with the auxiliary pump being driven, or in the first switching position thereof with the displacement pump being driven.

9. The hydraulic arrangement of claim 1, wherein at least one of the valve unit or the auxiliary valve unit can be controlled in order to change the switching position thereof in accordance with sensor signals of a pressure sensor which is hydraulically connected to the output of the auxiliary pump or the pump output.

10. The hydraulic arrangement of claim 1, wherein the valve unit has a control input which is hydraulically connected to the pump output of the displacement pump.

11. The hydraulic arrangement of claim 1, wherein at least one of the valve unit or the auxiliary valve unit can be electrically controlled directly or can be controlled via an electrically controllable hydraulic precontrol valve.

12. The hydraulic arrangement of claim 11, wherein the hydraulic precontrol valve has a control pressure connection which is hydraulically connected to a hydraulic control pressure input of the valve unit or the auxiliary valve unit, wherein the control pressure connection in one switching position of the precontrol valve is hydraulically connected to a hydraulic tank, and in another switching position of the precontrol valve is hydraulically connected to the output of the auxiliary pump.

13. A utility vehicle, comprising: a drive motor; and a hydraulic arrangement including: a hydraulic displacement pump and a supply connection as an interface for supplying hydraulic consumers of the utility vehicle; a displacement control unit which is dependent on an output pressure of the displacement pump for displacing the displacement pump; a hydraulic auxiliary pump and an auxiliary supply connection as an interface for alternatively supplying at least some of the consumers; and a hydraulic valve unit which is hydraulically arranged in a throughflow path between a pump output of the displacement pump and the supply connection; wherein the valve unit has a first switching position in which the pump output of the displacement pump is hydraulically connected to the supply connection and hydraulically separated from an output of the auxiliary pump, and a second switching position, in which the pump output of the displacement pump is hydraulically separated from the supply connection and hydraulically connected to the output of the auxiliary pump.

14. The utility vehicle of claim 13, wherein the drive motor is drivingly connected to the displacement pump.

15. The utility vehicle of claim 13, wherein the auxiliary supply connection is hydraulically connected to at least one of a brake system or a steering system of the utility vehicle.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0043] The detailed description of the drawings refers to the accompanying figures.

[0044] FIG. 1 shows a schematic illustration of a utility vehicle according to the disclosure.

[0045] FIG. 2 shows a hydraulic circuit diagram with the hydraulic arrangement according to a first embodiment of the disclosure.

[0046] FIG. 3 shows a hydraulic circuit diagram of the hydraulic arrangement according to another embodiment of the disclosure.

[0047] FIG. 4a shows another exemplary embodiment of a valve unit within the hydraulic arrangement according to the disclosure.

[0048] FIG. 4b shows another exemplary embodiment of a valve unit within the hydraulic arrangement according to the disclosure.

[0049] FIG. 5a shows a first exemplary embodiment of a precontrol valve for controlling the valve unit.

[0050] FIG. 5b shows another exemplary embodiment of the precontrol valve.

[0051] Like reference numerals are used to indicate like elements throughout the several figures.

DETAILED DESCRIPTION

[0052] FIG. 1 shows a schematic illustration of an agricultural utility vehicle 10 according to the disclosure, e.g., in the form of a tractor, having a drive train 20. The utility vehicle 10 further comprises a cab 12, a front vehicle axle 14 and a rear vehicle axle 26. The utility vehicle 10 can have one or more ground engaging means in the form of wheels 28. The drive train 20 comprises a drive motor 22 which may be in the form of an internal combustion engine and a gear mechanism structure 30 which may be composed of different individual gear mechanism components.

[0053] The utility vehicle 10 has a hydraulic arrangement 42 having a pump unit 40. As can be seen in FIGS. 2 and 3, the drive motor 22 can drive the gear mechanism structure 30 which drives a displacement pump 46 of the pump unit 40 via a gear mechanism component and a pump drive shaft 44. The hydraulic arrangement 42 may be integrated in the utility vehicle 10 in a modular manner. A modular installation of the hydraulic arrangement 42 in the utility vehicle 10 can be supported by different hydraulic interfaces. A supply connection 48, a return connection 50 and an auxiliary supply connection 52 can act as such interfaces.

[0054] According to FIG. 2, a pump output 54 of the pump unit 40 can be connected to the supply connection 48 via a hydraulic valve unit 56 in order to supply hydraulic consumers 58 of the utility vehicle 10. The consumers 58 include inter alia a steering system 60 and a brake system 62. A displacement control unit 64 for displacing a hydraulic conveying quantity of the displacement pump 46 is dependent on the output pressure p_a thereof and a load report pressure at the feedback connection 50.

[0055] The arrangement 42 further comprises an auxiliary pump unit 66 having an auxiliary pump 70 which is driven by an auxiliary pump motor 68 (for example, electric motor). The auxiliary pump output 72 thereof can be hydraulically connected to the auxiliary supply connection 52 via an auxiliary valve unit 74. Via the auxiliary pump unit 66, for example, hydraulic consumers, such as the steering system 60 and the brake system 62, which are important in technical driving terms in the event of a failure of the pump unit 40, can be alternatively supplied in the manner of emergency operation.

[0056] The valve unit 56 according to FIG. 2 is in the form of a 3/2-way valve. In the first switching position 56-0 thereof corresponding to the rest position, the pump output 54 is hydraulically connected to the supply connection 48 and hydraulically separated from the auxiliary pump output 72. In the second switching position 56-a, the pump output 54 is hydraulically separated from the supply connection 48 and hydraulically connected to the auxiliary pump output 72.

[0057] The auxiliary valve unit 74 according to FIG. 2 is in the form of a 2/2-way valve. In the first switching position 74-0 thereof corresponding to the rest position, the auxiliary pump output 72 is hydraulically connected to the auxiliary supply connection 52. In the second switching position 74-a, the auxiliary pump output 72 is hydraulically separated from the auxiliary supply connection 52.

[0058] At the input side, the displacement pump 46 and the auxiliary pump 70 are each connected to a hydraulic tank 76. The hydraulic medium which is conveyed to the consumers 58 flows back into the hydraulic tank 76.

[0059] A pressure sensor 78 with a pressure input 80 is connected to the auxiliary pump output 72. Alternatively, the pressure input 80 is connected to the pump output 54. A signal output 82 of the pressure sensor 78 is connected to an electrical control unit 84 (e.g., an electronic controller including a processor and memory) which processes inter alia the output signals or sensor signals S of the pressure sensor 78. In this manner, the control unit 84 can detect the current pressure which is applied to the auxiliary pump output 72 and/or the current output pressure p_a which is applied to the pump output 54. In accordance with this pressure detection, the control unit 84 can inter alia control the valve unit 56 and the auxiliary valve unit 74 in order to change the respective switching position thereof.

[0060] In order to support the operation of the hydraulic arrangement 42, a hydraulic non-return valve 86 is interposed between the auxiliary pump output 72 and an output 90 of the auxiliary pump unit 66. Furthermore, the auxiliary pump 70 is combined with a hydraulic pressure valve 88.

[0061] FIG. 3 shows another embodiment of the hydraulic arrangement 42. In this embodiment, there is no auxiliary valve unit 74. The output 90 of the auxiliary pump unit 66 is then directly hydraulically connected to the auxiliary supply connection 52.

[0062] The above-mentioned hydraulic interfacessupply connection 48, feedback connection 50, auxiliary supply connection 52can be arranged for example directly on the respective component (for example, pump unit 40, auxiliary pump unit 66, valve unit 56, auxiliary valve unit 74) of the hydraulic arrangement 42 or be arranged with spacing from the respective component of the hydraulic arrangement 42 by means of a line-like extension.

[0063] In another embodiment (FIG. 4a), the valve unit 56 further has, in addition to the first and second switching positions 56-0, 56-a, a third switching position in the form of a separation switching position 56-t. In the case of the activated separation switching position 56-t, the pump output 54 of the displacement pump 54 is hydraulically separated from the supply connection 48 and at the same time also hydraulically separated from the auxiliary pump output 72 or from the auxiliary pump unit 66.

[0064] The valve unit 56 with the two switching positions 56-0, 56-a and the valve unit 56 with the three switching positions 56-0, 56-a, 56-t may optionally be in the form of a constantly adjustable distributing valve, as illustrated in FIG. 4a.

[0065] In another embodiment (FIG. 4b), the valve unit 56 has a control input 92 which is hydraulically connected to the pump output 54 of the displacement pump 46. A specific switching position of the valve unit 56, e.g., the separation switching position 56-t, can thereby automatically be activated by the hydraulic control pressure which is applied to the control input 92. In the embodiment according to FIG. 4a, however, the separation switching position 56-t is activated by the electrical control by means of the control unit 84.

[0066] Very generally, the valve unit 56 and the auxiliary valve unit 74 can be electrically controlled directly via the control unit 84 in order to activate another switching position.

[0067] In the embodiment according to FIG. 4b, the valve unit 56 has such dimensions and the control thereof can be combined with the hydraulic control input 92 by the control unit 84 so that an activated electromagnet 94 together with a pressure limiting spring 96 retains the valve unit 56 in the second switching position 56-a until the predetermined desired pressure p_soll is reached at the pump output 54. This desired pressure p_soll results in the valve unit 56 being moved into the switching position 56-t via the control input 92.

[0068] Alternatively, the valve unit 56 and/or the auxiliary valve unit 74 can each be controlled via an electrically controllable hydraulic precontrol valve 98. The precontrol valve 98 is illustrated in FIG. 5a and FIG. 5b in two possible embodiments. In both embodiments, the precontrol valve 98 is in the form of a distributing valve with two switching positions 98-0, 98-a, wherein it can be constantly adjusted in the embodiment according to FIG. 5b. The switching position 98-0 may be the rest position of the precontrol valve 98. The precontrol valve 98 has a control pressure connection 100 which is hydraulically connected to a hydraulic control pressure input 102 of the valve unit 56 or the auxiliary valve unit 74. The control pressure connection 100 is hydraulically connected to a or the hydraulic tank 76 in the switching position 98-0. In the switching position 98-a, the control pressure connection 100 is hydraulically connected to the auxiliary pump output 72 or the output 90 of the auxiliary pump unit 66.

[0069] By means of the hydraulic logic unit described, the start phase of the drive motor 22 can be supported with particularly low energy losses, which affords technical advantages for example in the event of a cold start.

[0070] Before the utility vehicle 10 is started, the displacement control unit 64, for example the displacement cylinder thereof, is generally adjusted to a conveying position for a maximum conveying quantity as a result of the pressure relationships at the pump output 54 and at the feedback connection 50. However, one potential advantage of at least some implementations may be to keep the power consumption of the displacement pump 46 lowered in the start phase of the utility vehicle 10 and consequently to adjust the displacement control unit 64, e.g., the displacement cylinder thereof, to a conveying position for a lowered conveying quantity. This potential advantage may be achieved with the hydraulic arrangements 42 according to FIG. 2 and FIG. 3.

[0071] In the hydraulic arrangement 42 according to FIG. 2, an intended start of the drive motor 22 by the control unit 84 (for example, via received bus signals of a vehicle bus, such as, for example, ISOBUS, CAN) is detected from the rest positions or first switching positions 56-0, 74-0 of the valve unit 56 and the auxiliary valve unit 74, with the control unit subsequently switching the valve unit 56 and the auxiliary valve unit 74 into the second switching position 56-a, 74-a thereof. Furthermore, the auxiliary pump motor 68 is activated by the control unit 84 so that the auxiliary pump 70 is driven and the output pressure p_a at the pump output 54 increases while the displacement pump 46 is stopped. As soon as the displacement pressure p_a which increases has reached or exceeded a predetermined desired pressure p_soll-depending on the system, for example, approximately 26 bar, the displacement control unit 64 is in the minimal conveying position thereof so that the displacement pump 46 has no power consumption or has a low power consumption. The power consumption of the displacement pump 46 in the start phase of the utility vehicle 10 can thereby be significantly reduced, whereby the load on the drive motor 22 and the starter motor thereof is relieved in the start phase.

[0072] Since the output pressure p_a is continuously detected by means of the pressure sensor 78, the control unit 84 can control the hydraulic arrangement 42 in the desired manner after reaching or exceeding the predetermined desired pressure p_soll. For example, after reaching or exceeding the predetermined desired pressure p_soll, the auxiliary pump motor 68 is reduced with respect to the drive speed thereof or switched off. The drive motor 22 is started, wherein after reaching a stable speed the valve unit 56 and the auxiliary valve unit 74 are moved into their respective first switching position 56-0, 74-0 or into the rest position thereof. The valve unit 56 then allows supply of the hydraulic consumers by the displacement pump 46.

[0073] The hydraulic arrangement 42 according to FIG. 3 operates unlike the embodiment according to FIG. 2 without the auxiliary valve unit 74 so that the output 90 is hydraulically connected directly to the auxiliary supply connection 52. In the event of an intended start of the drive motor 22, the hydraulic arrangement 42 according to FIG. 3 is controlled in principle the same way as in the variant according to FIG. 2. In this case, the valve unit 56 is initially switched from the rest position or the first switching position 56-0 into the second switching position 56-a thereof. Subsequently, as described with reference to FIG. 2, the auxiliary pump 70 is driven. Should leaks occur at the hydraulic consumers 58, however, the auxiliary pump 70 requires a greater drive power than in the variant according to FIG. 2 in order to reach the predetermined desired pressure p_soll at the pump output 54. Furthermore, during the start phase of the drive motor 22, continued operation of the auxiliary pump 70 may be advantageous in order in the start phase to maintain the necessary hydraulic pressure p_soll at the pump output 54.

[0074] Alternatively, in the embodiment according to FIG. 3, the above-mentioned continued operation of the auxiliary pump 70 during the start phase of the drive motor 22 can be avoided by the valve unit 56 being provided with the additional separation switching position 56-t (FIG. 4a, FIG. 4b). After reaching or exceeding the predetermined desired pressure p_soll, the valve unit 56 can then be moved out of the second switching position 56-a initially into the separation switching position 56-t in order to maintain the reached desired pressure p_soll. At a suitable time, for example after the completed start of the drive motor 22, the valve unit 56 is moved by means of the control unit 84 out of the separation switching position 56-t into the rest position or first switching position 56-0 thereof.

[0075] As used herein, e.g. is utilized to non-exhaustively list examples and carries the same meaning as alternative illustrative phrases such as including, including, but not limited to, and including without limitation. Unless otherwise limited or modified, lists with elements that are separated by conjunctive terms (e.g., and or or) and that are also preceded by the phrase one or more of or at least one of indicate configurations or arrangements that potentially include individual elements of the list, or any combination thereof. For example, at least one of A, B, and C or at least one of A, B, or C or one or more of A, B, and C or one or more of A, B, or C indicates the possibilities of only A, only B, only C, or any combination of two or more of A, B, and C (e.g., A and B; B and C; A and C; or A, B, and C).

[0076] The teachings may be described herein in terms of functional and/or logical block components and/or various processing steps. It should be realized that such block components may be comprised of any number of hardware, software, and/or firmware components configured to perform the specified functions.

[0077] Terms of degree, such as generally, substantially or approximately are understood by those of ordinary skill to refer to reasonable ranges outside of a given value or orientation, for example, general tolerances or positional relationships associated with manufacturing, assembly, and use of the described embodiments.

[0078] While the above describes example embodiments of the present disclosure, these descriptions should not be viewed in a limiting sense. Rather, other variations and modifications may be made without departing from the scope and spirit of the present disclosure as defined in the appended claims.