HYDRAULIC ARRANGEMENT AND UTILITY VEHICLE

Abstract

A hydraulic arrangement for a utility vehicle. The arrangement may include a hydraulic displacement pump which is connected via a pump output to a supply connection as a hydraulic interface for supplying hydraulic consumers of the utility vehicle. In addition, the device may include a hydraulic auxiliary pump and an auxiliary supply connection as a hydraulic interface for alternatively supplying at least some of the consumers. The device may include a displacement control unit which is dependent on an output pressure of the auxiliary pump for displacing the displacement pump in such a manner that a hydraulic working connection of a displacement cylinder of the displacement control unit is connected to an output of the auxiliary pump.

Claims

1. A hydraulic arrangement for a utility vehicle, the hydraulic arrangement comprising: a hydraulic displacement pump which is connected via a pump output to a supply connection as a hydraulic interface for supplying hydraulic consumers of the utility vehicle; a hydraulic auxiliary pump and an auxiliary supply connection as a hydraulic interface for alternatively supplying at least some of the consumers; and a displacement control unit which is dependent on an output pressure of the auxiliary pump for displacing the displacement pump in such a manner that a hydraulic working connection of a displacement cylinder of the displacement control unit is connected to an output of the auxiliary pump.

2. The hydraulic arrangement of claim 1, wherein the displacement cylinder includes a single-acting displacement cylinder.

3. The hydraulic arrangement of claim 1, wherein a non-return valve is hydraulically connected upstream of the working connection in the throughflow path between the output of the auxiliary pump and the working connection of the displacement cylinder, wherein the throughflow direction of the non-return valve is orientated in the direction of the working connection.

4. The hydraulic arrangement of claim 1, wherein a retention valve unit which has two different switching positions is hydraulically connected in the hydraulic throughflow path between the working connection of the displacement cylinder, on the one hand, and a return connection and the pump output, on the other hand, in such a manner that the retention valve unit acts as a hydraulic interruption or as a hydraulic connection in the throughflow path depending on the activated switching position thereof.

5. The hydraulic arrangement of claim 4, wherein the retention valve unit has, in the throughflow path at the connection side thereof facing away from the working connection of the displacement cylinder, a hydraulic valve connection which can be connected to the pump output in accordance with an output pressure of the displacement pump.

6. The hydraulic arrangement of claim 5, wherein the retention valve unit has a control pressure input which is active in the switching direction and which is hydraulically connected to the valve connection.

7. The hydraulic arrangement of claim 1, wherein at least one valve unit which has a plurality of switching positions and which has two hydraulic control inputs which are opposite each other in the switching direction is arranged in the throughflow path between the working connection or the retention valve unit, on the one hand, and a return connection and the pump output, on the other hand, wherein one of the two hydraulic control inputs is hydraulically connected to the pump output and the other of the two hydraulic control inputs is either hydraulically connected to the return connection or is hydraulically connected to a feedback connection which acts as an interface for a pressure feedback of consumers.

8. The hydraulic arrangement of claim 1, wherein the hydraulic arrangement has at least one of the following features with an increasing output pressure at the output of the auxiliary pump after reaching or exceeding a predetermined desired pressure at the output of the auxiliary pump: the retention valve unit is in the switching position thereof which acts as a hydraulic connection in the throughflow path, a drive of the auxiliary pump is reduced or deactivated, or the displacement pump is driven.

9. The hydraulic arrangement of claim 1, wherein a pressure sensor which generates sensor signals is hydraulically connected to the output of the auxiliary pump, wherein in accordance with the sensor signals at least one of 1) a drive of the auxiliary pump can be controlled or 2) the retention valve unit can be controlled in order to change the switching position thereof.

10. A utility vehicle, comprising: a drive motor; and a hydraulic arrangement including: a hydraulic displacement pump which is connected via a pump output to a supply connection as a hydraulic interface for supplying hydraulic consumers of the utility vehicle; a hydraulic auxiliary pump and an auxiliary supply connection as a hydraulic interface for alternatively supplying at least some of the consumers; and a displacement control unit which is dependent on an output pressure of the auxiliary pump for displacing the displacement pump in such a manner that a hydraulic working connection of a displacement cylinder of the displacement control unit is connected to an output of the auxiliary pump.

11. The utility vehicle of claim 10, wherein the drive motor is drivingly connected to the displacement pump.

12. The utility vehicle of claim 10, 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

[0037] The detailed description of the drawings refers to the accompanying figures.

[0038] FIG. 1 shows a schematic illustration of a utility vehicle according to the disclosure.

[0039] FIG. 2 shows a hydraulic circuit diagram with the hydraulic arrangement according to the disclosure in one embodiment.

[0040] FIG. 3a shows a hydraulic circuit diagram of the detail III within the hydraulic arrangement according to FIG. 2 in a first embodiment.

[0041] FIG. 3b shows a hydraulic circuit diagram of the detail III within the hydraulic arrangement according to FIG. 2 in another embodiment.

[0042] FIG. 3c shows a hydraulic circuit diagram of the detail III within the hydraulic arrangement according to FIG. 2 in another embodiment.

DETAILED DESCRIPTION

[0043] FIG. 1 shows a schematic illustration of an agricultural utility vehicle 10 according to the disclosure, for example 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.

[0044] The utility vehicle 10 has a hydraulic arrangement 42 having a pump unit 40. According to FIG. 2, 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, an auxiliary supply connection 52 and a return connection 92 can act as such interfaces.

[0045] According to FIG. 2, a pump output 54 of the pump unit 40 is connected to the supply connection 48 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 the displacement pump 46 is dependent on an output pressure of an auxiliary pump unit 66. This output pressure may be referred to as the displacement pressure p_v for influencing the displacement control unit 64.

[0046] The auxiliary pump unit 66 which acts as a component of the hydraulic arrangement 42 contains an auxiliary pump 70 which is driven by an auxiliary pump motor 68 (for example, electric motor). The auxiliary pump output 72 thereof is hydraulically connected to the auxiliary supply connection 52. Via the auxiliary pump unit 66, hydraulic consumers, for example 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.

[0047] At the input side, the displacement pump 46 and the auxiliary pump 70 are each connected to a tank container or hydraulic tank 76. The hydraulic medium which is conveyed to the consumers 58 flows via return lines back into the hydraulic tank 76.

[0048] The above-mentioned hydraulic interfaces-supply connection 48, feedback connection 50, auxiliary supply connection 52, return connection 92of the hydraulic arrangement 42 can be arranged, for example, directly on or in the pump unit 40 or auxiliary pump unit 66, or be arranged with spacing from the pump unit 40 or auxiliary pump unit 66 by means of a line-like extension.

[0049] A pressure sensor 78 with a pressure input 80 is connected to the auxiliary pump output 72. A signal output 82 of the pressure sensor 78 is connected to an electrical control unit 84 (e.g., a 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 or the current displacement pressure p_v. In accordance with this pressure detection, the control unit 84 can inter alia control the auxiliary pump motor 68.

[0050] 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 limiting valve 88.

[0051] FIG. 3a, FIG. 3b and FIG. 3c show the pump unit 40 with different embodiments of the displacement control unit 64. As can also be seen with reference to FIG. 2, in all the embodiments the auxiliary pump output 72 or the output 90 of the auxiliary pump unit 66 is hydraulically connected to a pressure connection 94 of the pump unit 40.

[0052] The displacement control unit 64 has a single-acting displacement cylinder 96. A working connection 98 of the displacement cylinder 96 is hydraulically connected to the output 90 or the auxiliary pump output 72 via the pressure connection 94. A check valve 100 is connected upstream of the working connection 98 in the throughflow path between the output 90 and the working connection 98. In this case, the throughflow direction of the check valve 100 is orientated in the direction of the working connection 98.

[0053] In the pump unit 40 according to FIG. 3a, two valve units 102, 104 each having two different switching positions 102-0, 102-a or 104-0, 104-a are hydraulically connected in the throughflow path between the working connection 98, on the one hand, and the return connection 92 and the pump output 54, on the other hand. In this case, the working connection 98 can be connected to the return connection 92 in the switching position 102-0 which forms the rest position, wherein this connection is dependent on the activated rest position 104-0 of the valve unit 104. In a second switching position 102-a of the valve unit 102, the working connection 98 is hydraulically connected to the pump output 54.

[0054] The two valve units 102, 104 can each be in the form of a distributing valve or proportional valve with intermediate positions and the two above-mentioned switching positions 102-0, 102-a or 104-0, 104-a as end positions.

[0055] The valve units 102, 104 each have two hydraulic control inputs which are opposite each other in a switching direction. A first control input 106 or 110 is hydraulically connected to the pump output 54 of the displacement pump 46 while a second control input 108 of the valve unit 102 is hydraulically connected to the return connection 92 and a second control input 112 of the valve unit 104 is hydraulically connected to the feedback connection 50.

[0056] The embodiment according to FIG. 3b differs from the variant according to FIG. 3a substantially in that a retention valve unit 114 having two different switching positions 114-0, 114-a is hydraulically connected in the hydraulic throughflow path between the working connection 98, on the one hand, and the return connection 92 and the pump output 54, on the other hand. The retention valve unit 114 is arranged in the throughflow path between the two valve units 102, 104. In accordance with the activated switching position 114-0 or 114-a thereof, the retention valve unit 114 acts either as a hydraulic connection (with the rest position or switching position 114-0 being activated) or as a hydraulic interruption (with the switching position 114-a being activated) in the throughflow path. The retention valve unit 114 can be electrically actuated by means of the control unit 84 in order to activate or deactivate the different switching positions 114-0, 114-a thereof.

[0057] The embodiment according to FIG. 3c differs from the variant according to FIG. 3b substantially as a result of another arrangement of the retention valve unit 114 in the throughflow path and a different construction of the retention valve unit 114. In FIG. 3c, the retention valve unit 114 has, in the throughflow path at the connection side thereof facing away from the working connection 98 of the displacement cylinder 96, a hydraulic valve connection 116 which can be connected to the pump output 54 by means of the valve unit 102 in accordance with an output pressure p_a of the displacement pump 46. A control pressure input 118, which is active in a switching direction, of the retention valve unit 114 is hydraulically connected to the valve connection 116.

[0058] By means of the hydraulic logic unit described, the start phase of the drive motor 22 can be supported with a relatively small energy consumption and low energy losses, which affords potential technical advantages for example in the event of a cold start.

[0059] Before the utility vehicle 10 is started, the displacement control unit 64, for example the displacement cylinder 96 thereof, is generally adjusted to a conveying position for an increased conveying quantity as a result of the pressure relationships at the pump output 54, at the feedback connection 50 and at the return connection 92. However, one potential advantage of some embodiments is to keep the power consumption of the displacement pump 46 lower in the start phase of the utility vehicle 10 and consequently to adjust the displacement control unit 64 to a conveying position for a reduced conveying quantity. This may be achieved with the hydraulic arrangements 42 according to FIG. 3a, FIG. 3b and FIG. 3c.

[0060] In the hydraulic arrangement 42 according to FIG. 3a, 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, ISO, CAN) is detected from the rest positions or first switching positions 102-0, 104-0 of the valve units 102, 104, with the control unit subsequently activating the auxiliary pump motor 68 so that the auxiliary pump 70 is driven while the displacement pump 46 is stopped. As soon as the displacement pressure p_v which increases at the working connection 98 has reached or exceeded a predetermined desired pressure p_soll-depending on the system of the displacement control unit 64 for example less than 10 bar-the displacement control unit 64 is in the reduced conveying position thereof so that the displacement pump 46 (in the case of the operation thereof) has no power consumption or has only 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.

[0061] Since the displacement pressure p_v 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 drive motor 22 is started and the displacement pump 46 is driven with a low or reduced power consumption. The auxiliary pump motor 68 can be reduced with respect to the drive power thereof or switched off again. The valve unit 102 can cause the displacement cylinder 96 to automatically adjust the conveying position with a reduced conveying quantity when an increased output pressure p_a (in some examples including a maximum output pressure) is reached at the driven displacement pump 46.

[0062] The hydraulic arrangement 42 according to FIG. 3b operates unlike the embodiment according to FIG. 3a additionally with the retention valve unit 114. In the event of an intended start of the drive motor 22, the hydraulic arrangement 42 according to FIG. 3b, for example the auxiliary pump motor 68, is controlled in principle in the same way as in the variant according to FIG. 3a. In addition, the control unit 84 activates at the retention valve unit 114 the switching position 114-a thereof which acts as an interruption. Pressure losses at the working connection 98 as a result of any leaks can thereby be avoided with increasing displacement pressure p_v. At or after the start of the drive motor 22, the retention valve unit 114 can again be moved into the rest position or switching position 114-0 thereof which acts as a hydraulic connection. If the retention valve unit 114 is moved by the control unit 84 in a delayed manner into the rest position or switching position 114-0 thereof which acts as a hydraulic connection, the output pressure p_a increases further or perceptibly. In order to take this circumstance into account, therefore, the conveying position with a reduced conveying quantity is automatically adjusted again at the displacement pump 46 when the increased output pressure p_a is reached at the driven displacement pump 46 by the valve unit 102.

[0063] The retention valve unit 114 used to protect against any leaks according to FIG. 3c is, unlike the variant according to FIG. 3b, provided with the control pressure input 118. In the event that the retention valve unit 114 is moved by the control unit 84 in a delayed manner into the rest position or switching position 114-0 thereof which acts as a hydraulic connection, the output pressure p_a also increases further or perceptibly in this case. It becomes possible via the control pressure input 118 for the retention valve unit 114 to be moved into the rest position or switching position 114-0 which acts as a hydraulic connection when the increased output pressure p_a is reached at the driven displacement pump 46. The conveying position with a reduced conveying quantity can thereby be automatically adjusted via the displacement cylinder 96.

[0064] 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 one or more of A, B, and 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).

[0065] 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.

[0066] Terms of degree, such as generally, substantially or approximately may be 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.

[0067] Any advantages described herein need not be achieved by every embodiment or example of the disclosure.

[0068] 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.