Patent ID: 12252864

DETAILED DESCRIPTION OF EXAMPLE EMBODIMENTS OF THE INVENTION

FIG.1shows a working machine in the form of a loader vehicle1, in particular an articulated wheel loader, operationally connected to a work attachment2via a work attachment connection arrangement3arranged on a pair of lift arms26on the loader vehicle1. The work attachment connection arrangement3comprises electrical and mechanical connections. The work attachment2is provided with an electrically driven work tool in the form of a sweeper/rotary broom4. The loader vehicle1is fully electrically operated and propelled.

FIG.2shows a schematic view of the electrical connections and components of the work attachment2and the loader vehicle1according toFIG.1. As indicated inFIG.2, the loader vehicle1is provided with a first electric motor5arranged for propulsion of the loader vehicle1and an additional electric motor6arranged to drive a hydraulic pump (not shown) for powering hydraulic systems (not shown), such as steering of the loader vehicle1and movement of the lift arms26.

A first rechargeable battery7is configured to supply the electric motors5,6with electric power via an electric power circuit8connecting the electric motors5,6and the first rechargeable battery7. The motors5,6are connected to the electric power circuit8via DC/AC converters31,32. All electric motors in this example run on AC current/voltage.

The work attachment connection arrangement3comprises, besides a mechanical connection for connecting the work attachment2mechanically to the loader vehicle1, a first electrical connector15aconnected to the electric power circuit8of the loader vehicle1. The first electric connector15ais connected to a corresponding electrical connector15barranged on the work attachment2, wherein the corresponding electrical connector15bis connected to an auxiliary rechargeable battery17arranged on the work attachment2. Electric connection of the auxiliary rechargeable battery17to the electric power circuit8of the loader vehicle1is thus established when the work attachment2is connected to the loader vehicle1via the work attachment connection arrangement3.

The work attachment connection arrangement3further comprises a second electrical connector16aconnected to the electric power circuit8of the loader vehicle1. The second electrical connector16ais connected to a corresponding electrical connector16barranged on the work attachment2and connected to an electric work tool motor18via a further DC/AC converter33. The electric work tool motor18is arranged on the work attachment2and configured to drive the sweeper/rotary broom4. Electric connection of the electric work tool motor18to the electric power circuit8of the loader vehicle1is thus established when the work attachment2is connected to the loader vehicle1via the work attachment connection arrangement3.

A charging connection component23, configured to be connected to an external battery charging unit, is arranged on the loader vehicle1and connected to the first rechargeable battery7. An auxiliary charging connection component24, configured to be connected to an external battery charging unit, is arranged on the work attachment2and connected to the auxiliary rechargeable battery17.

The loader vehicle1further comprises a first bidirectional DC/DC converter21connected to the electric power circuit8and to the first rechargeable battery7; the electric power circuit8and the first rechargeable battery7are connected via said first bidirectional DC/DC converter21. The first bidirectional DC/DC converter21is configured to control a direction and an intensity/magnitude of an electric current that flows between the electric power circuit8and the first rechargeable battery7.

The loader vehicle1further comprises a second bidirectional DC/DC converter22connected to the electric power circuit8and to the first electric connector15a; the electric power circuit8and the first electric connector15aare connected via said second bidirectional DC/DC converter22. The second bidirectional DC/DC converter22is configured to control a direction and an intensity/magnitude of an electric current that flows between the electric power circuit8and the first electric connector15aand thereby to control a direction and an intensity/magnitude of an electric current that flows between the electric power circuit8and the auxiliary rechargeable battery17when the work attachment2is connected to the loader vehicle1via the work attachment connection arrangement3.

The loader vehicle also comprises a control system configured to control the operation of the loader vehicle1and to, when the work attachment2is connected to the loader vehicle1via the work attachment connection arrangement3, control the operation of the work attachment2. The control system comprises a control unit10and a control connection network11connecting the control unit10with components the control unit10is configured to control, such as the electric motors5,6,18(via their DC/AC converters31,32,33) and the first and second bidirectional DC/DC converters21,22. A third connector11aarranged at the work attachment connection arrangement3is configured to be connected to a corresponding connector11barranged on the work attachment2. This corresponding connector11bis connected to the electric work tool motor18, via the converter33, so as to allow the control unit10to control the electric work tool motor18when the work attachment2is connected to the loader vehicle1via the work attachment connection arrangement3.

The control unit10may be controllably connected to further components, such as the batteries7,17(e.g. to the BMS of the batteries to obtain information on charging state, temperature etc.), the charging connection components23,24(to get information on whether a charging unit is connected etc.), and other components not shown inFIG.2, such as components related to the steering of the loader vehicle1.

The loader vehicle1is in this case an articulated vehicle comprising a pivot joint in its construction.

In this example the nominal voltage of both the batteries7,17and the electric power circuit8is 48 V.

Both batteries7,17are connected to the electric power circuit8via corresponding first and second bidirectional DC/DC converters21,22capable of controlling to what extent and in which direction electric current, i.e. electric energy, is to flow between each battery7,17and the power circuit8. This means that during operation of the combination of the loader vehicle1and the work attachment2it can be controlled to what extent each battery7,17should contribute to the power output.

Each battery7,17can be used individually to power both the loader vehicle1(i.e. the motors5and6) and the work attachment (i.e. the work tool motor18). Both batteries7,17may be used simultaneously as power source, to the same or different extent. In many situations it is advantageous to use the auxiliary battery17until it reaches a certain minimum level of charge and then switch to the first battery7. This way the loader vehicle can still be in operation after having disconnected the work attachment2. In any case, the additional capacity of electric energy provided by the auxiliary battery17extends the time of operation for the combination of the vehicle1and the work attachment2compared to the case where the work attachment2is not provided with any auxiliary battery.

If charging the combination of the vehicle1and the work attachment2when connected to each other it is in principal possible to use any of the charging connection component24, although it may be preferred to use the charging connection component23arranged on the loader vehicle1to primarily charge the first battery7. The loader vehicle1and the work attachment2may be disconnected and charged separately via the corresponding charging connection component24.

It is to be understood that the present invention is not limited to the embodiments described above and illustrated in the drawings; rather, the skilled person will recognize that many changes and modifications may be made within the scope of the appended claims.