GROUND MILLING MACHINE WITH ENERGY SUPPLY SYSTEM, METHOD FOR OPERATING A GROUND MILLING MACHINE, AND METHOD FOR RETROFITTING A GROUND MILLING MACHINE

Abstract

The present invention relates to a self-propelled ground milling machine, in particular, a road cold milling machine, stabilizer or recycler, comprising a milling device for milling the ground at a milling depth, a machine frame supported by front and rear travel units, a primary drive unit arranged on the machine frame, in particular, an internal combustion engine, an on-board electrical system, and a generator driven by the primary drive unit, which feeds electrical energy generated by it into the on-board electrical system.

Claims

1. A self-propelled ground milling machine comprising: a milling device for milling a ground at a milling depth; a machine frame supported by front and rear travel units; a primary drive unit arranged on the machine frame; an on-board electrical system; and a first generator driven by the primary drive unit, which feeds electrical energy generated by it into the on-board electrical system, wherein an additional second generator driven by the primary drive unit is provided.

2. The self-propelled ground milling machine according to claim 1, wherein the two generators include at least one of the following features: the two generators are of identical design; the two generators are three-phase generators; the two generators are both connected to the same on-board electrical system; the two generators are connected such that the two generators generate essentially the same electrical power given a same power applied to the respective generator; and the two generators are driven simultaneously by the primary drive unit.

3. The self-propelled ground milling machine according to claim 1, wherein the two generators include at least one of the following features: the two generators are arranged offset one behind the other in an axial direction of a rotation axis of a crankshaft of the primary drive unit; and the two generators have input shafts that project from a main output side of the primary drive unit in a direction parallel to the rotation axis of the crankshaft; one of the two generators is driven by a single-stage traction drive; one of the two generators is driven by a two-stage traction drive; a gear ratio from an output axle of the primary drive unit to the input shafts of the two generators is identical; and the two generators are both arranged on a same side of the primary drive unit.

4. The self-propelled ground milling machine according to claim 1, wherein a control unit is provided which controls the feed of electrical energy by the two generators into the common on-board electrical system.

5. The self-propelled ground milling machine according to claim 1, wherein a mounting frame flanged to an engine mount is provided, on which only one of the two generators is arranged.

6. The self-propelled ground milling machine according to claim 1, wherein the additional second generator can be retrofitted.

7. A method for operating a ground milling machine according to claim 1, wherein electrical energy required for operating the ground milling machine is generated by the two generators driven simultaneously by the primary drive unit and is fed into a common on-board electrical system.

8. The method according to claim 7, further comprising: simultaneously feeding electrical energy into the common on-board electrical system in a manner synchronized with each other such that a sum of charge components fed into the on-board electrical system via the two generators per unit of time is at least essentially constant.

9. A method for retrofitting a ground milling machine according to claim 1, further comprising: doubling a cross-sectional area of lines in a charging circuit, either by installing one or more additional lines or by replacing previous lines by lines having essentially double the cross-sectional area in the charging circuit; and/or arranging the additional second generator in direct adjacency to the first generator; and/or arranging the additional second generator on a mounting structure that is rigid with respect to the first generator.

10. The self-propelled ground milling machine according to claim 1, wherein the self-propelled ground milling machine comprises a road milling machine, a stabilizer or a recycler.

11. The self-propelled ground milling machine according to claim 1, wherein the primary drive unit comprises an internal combustion engine.

12. The self-propelled ground milling machine according to claim 2, wherein the two generators are driven simultaneously by the primary drive via a traction drive driven by a pulley seated on a rotation axis of a crankshaft of the primary drive unit.

13. The self-propelled ground milling machine according to claim 5, wherein the control unit comprises a charge controller.

Description

BRIEF DESCRIPTION OF THE DRAWINGS

[0023] The present invention will be described in more detail below by reference to the embodiment examples shown in the figures; In the schematic figures:

[0024] FIG. 1 is a side view of a ground milling machine of the center rotor type;

[0025] FIG. 2 is a schematic top view of individual components of a drive system of the ground milling machine of FIG. 1;

[0026] FIG. 3 is a top view of a power take-off side of the primary drive unit;

[0027] FIG. 4 is an oblique perspective top view of the power take-off side of the primary drive unit of FIG. 3; and

[0028] FIG. 5 is an oblique perspective top view of the detail shown in FIG. 4.

[0029] Structurally or functionally like components are designated by like reference numerals in the figures, although not every recurring component is designated separately throughout the figures.

DETAILED DESCRIPTION OF THE INVENTION

[0030] FIG. 1 shows a ground milling machine 1 of the road cold milling machine type (center rotor type) with an operator platform 2 and a machine frame or chassis 3. The ground milling machine 1 is self-propelled and has travel units 6 for this purpose, for example crawler tracks or wheels. During milling operation, the ground milling machine machine 1 moves in the working direction a over the ground 7 to be processed. While doing so, the ground milling machine 1 mills the ground 7 at a milling depth with a milling drum 9 of a milling device 20 mounted for rotation about the rotation axis 10 in a milling drum box 8. The milled material removed may, for example, be transferred in working direction a via a discharge device 5, for example a conveyor belt, to a transport vehicle not shown and transported away by it. Moreover, the ground milling 1 may comprise a drive train 13. In order to cool components of this drive train 13, a cooling air supply is provided, among other things, as part of a cooling system, which is configured such that supply air 11 is drawn in at the top side of the ground milling machine 1 in a region of the ground milling machine 1 that is located behind the operator platform 2 in the working direction a. Via exhaust air openings arranged at the rear of the ground milling machine 1, the heated exhaust air 12 is blown out to the rear in the opposite direction to the working direction a and diagonally upward (for example through corresponding guide vanes in the outlet region).

[0031] An exemplary drive train 13 of the ground milling machine 1, in particular, for a road cold milling machine, is shown schematically in FIG. 2. It may comprise an internal combustion engine 14, for example a diesel engine, as the primary drive unit, the crankshaft of which rotates about the rotation axis D. The crankshaft may be connected to a clutch 15. A pump transfer gear 16 may adjoin the clutch in the axial direction of the rotation axis. Several units 18, such as, in particular, one or more hydraulic pumps, also in tandem arrangement, of a hydraulic system, may be flanged to distributor shafts of the pump transfer gear 16 and driven by it. The hydraulic system may, for example, be configured such that hydraulic pumps are used to drive hydraulic motors, which are used, for example, to drive the travel units 6 or to drive the conveyor 5 of the ground milling machine 1. Other actuators, such as linear actuators, may also be supplied with hydraulic drive energy via this system, for example, for shield control of the milling device 20, for adjustment of the conveyor device 5, etc. All required hydraulic pumps of the ground milling machine 1 may be coupled to the pump transfer gear 16 and supplied with energy by it. A shifting clutch 19 may adjoin the pump transfer gear 16 in the axial direction of the rotation axis, which in turn is in drive connection with a drive roller 21 of a traction drive 22 driving the milling drum 9. The rotation axis D can be parallel to the rotation axis 10 of the milling drum and thus horizontal and perpendicular to the forward direction a.

[0032] Part of the hydraulic system is also a hydraulic tank 23, which, as shown in FIG. 2, is arranged above the pump transfer gear 16 and in the direction of the rotation axis between the internal combustion engine and the traction drive 22. The arrangement may further include two air filters 26 arranged upstream and downstream of the hydraulic tank 23, as viewed in the forward direction a at the level of the hydraulic tank 23. Toward the internal combustion engine, supply lines 27 extend from each of the air filters 26 and, as shown in the top view in FIG. 2, converge at the level of the internal combustion engine to form a common air supply line 28.

[0033] The ground milling machine may comprise a plurality of electrical consumers, such as display devices 30, cameras 31, external lighting devices 32, etc. To supply these electrical consumers, the ground milling machine may comprise an on-board electrical system not specified in detail in the figures. One or more batteries/accumulators may be part of this on-board electrical system. Electrical energy can be generated simultaneously on the ground milling machine 1 with the aid of generators 33 and 34. Their possible arrangement is shown by way of example in FIGS. 3 to 5. Not shown in the figures is a control unit that communicates with the generators 33 and 34 and controls their feed to the common on-board electrical system of the ground milling machine 1.

[0034] The two electrical generators 33 and 34 may be of identical design. They are connected in the region of the power take-off side of the same primary drive unit 14 opposite the main output side connected to coupling 15. The two generators 33 and 34 are driven by means of traction drives, which are specifically located at least partially on the crankshaft rotation axis D. The traction drive 35 toward the generator 33 is single-stage. The traction drive 36, on the other hand, includes two belts arranged in series. This makes it possible to drive both generators 33 and 34 simultaneously from the primary drive unit 14. The electrical energy generated by the two generators 33 and 34 is fed into the common on-board electrical system. Both generators 33 and 34 thus supply electrical energy to a common on-board electrical system rather than to separate on-board electrical systems.

[0035] The generator 33 is arranged on a mounting frame 37, which is flanged to an engine mount via threaded connections. Thus, the mounting frame 37 can be easily dismounted or, conversely, easily retrofitted together with the generator 33 if the currently selected setup of the ground milling machine 1 has an increased overall demand for electrical energy.

[0036] The ground milling machine may also have an auxiliary drive via which drive energy can be generated independently and with the primary drive unit switched off. This auxiliary drive, for example an internal combustion engine with significantly less power than the primary drive unit, may drive a generator (not shown in the figures). It is essential, however, that this generator is not drivable by the primary drive unit and, conversely, neither of the generators 33 and 34 is drivable via said auxiliary drive.

[0037] While various aspects in accordance with the principles of the invention have been illustrated by the description of various embodiments, and while the embodiments have been described in considerable detail, they are not intended to restrict or in any way limit the scope of the invention to such detail. The various features shown and described herein may be used alone or in any combination. Additional advantages and modifications will readily appear to those skilled in the art. The invention in its broader aspects is therefore not limited to the specific details, representative apparatus and methods and illustrative examples shown and described. Accordingly, departures may be made from such details without departing from the scope of the general inventive concept.