WO2022056579A1

WO2022056579A1 - An underground truck

Info

Publication number: WO2022056579A1
Application number: PCT/AU2021/050965
Authority: WO
Inventors: Scott Mcfarlane
Original assignee: Bis Industries Limited
Priority date: 2020-09-17
Filing date: 2021-08-25
Publication date: 2022-03-24
Also published as: AU2021344442A1

Abstract

A truck 10 has a front chassis 12 and a rear chassis 14, each having at least 2 axles 20, 22, 24, 26, coupled by an articulated joint 16 providing a single degree of freedom being rotation about an axis 18 of the joint 16. Each chassis 12, 14 is provided with at least two axles. A bin 28 is supported on the rear chassis 14. The truck 10 is a hybrid electric truck having a combustion engine 30 electrically coupled to a first electric motor 32 on the front chassis and a second electric motor 34 on the rear chassis. The first electric motor 32 is mounted on the front chassis 12 and a rear axle 22 by a single drive shaft. The second electric motor 34 is mounted on the rear chassis 14 and drives both axles 24 and 26. Also the second electric motor 34 is mounted off centre of a centreline of the second chassis. The engine 30 is mounted on the front chassis 12 and coupled via a transmission 36 to an electric generator electrically coupled to distribution unit 42 connected to a battery pack 44 providing DC storage, the first electric motor 32 through a bank of inverters 46 and the second electric motor 34 through a bank of inverters 48.

Description

AN UNDERGROUND TRUCK

TECHNICAL FIELD

An underground truck is disclosed. The underground truck is suited to operating in an underground mine having a profile of 5.5 m x 5.5 m.

BACKGROUND ART

The primary purpose of an underground truck is to haul ore from a deep mine, for example around 1000 m or more, deep. The typical duty cycle for an underground truck is that it travels uphill loaded and downhill empty. Underground mines may be designed with a decline grade of about 14%. However due to ore body constraints small sections can exist with grades of up to 20%.

Underground mines may also be constructed to have a profile of about 5.5 m x 5.5 m. To be operable in such a mine an underground truck is limited in size so that it can physically fit in the mine and traverse a 90° corner. This places limitations on many aspects of the truck including its overall length, tyre size and maximum payload.

Currently available underground trucks that can operate in these conditions include the EPIROC® MT65, SANDVIK®TH663i and CATERPILLAR® AD60. The payload of these trucks is in the range of 63-65 tonnes. Each are constructed with two axles which use 35/65R33 tyres. These tyres have a diameter of about 2 m and a width of about 900 mm. The tyre size affects the height of the truck and maximum volume of its bin and thus the carrying capacity of the truck. The tyre capacity also controls the amount of payload these trucks can carry. Each of these truck use diesel engines and incorporate a drive train which includes a six speed, or more than six speeds, transmission.

The above references to the background art do not constitute an admission that the art forms a part of the common general knowledge of a person of ordinary skill in the art.

The above references are also not intended to limit the application of the underground truck as disclosed herein.

It is to be understood that, if any prior art is referred to herein, such reference does not constitute an admission that the prior art forms a part of the common general knowledge in the art, in Australia or any other country. SUMMARY OF THE DISCLOSURE

In a first aspect there is disclosed an underground vehicle operable in an underground mine comprising: a front chassis and a rear chassis coupled together by an articulated joint; each chassis being provided with at least two axles; and a bin mounted on the rear chassis; wherein the bin is dimensioned to enable the underground truck to carry a payload of up to 90,000 kg.

The underground vehicle may comprise a combustion engine and first and second electric motors, wherein the combustion engine is electrically coupled to the first and second electric motors, the first electric motor coupled to deliver torque to at least one of the axles on the front chassis, and the second electric motor coupled to deliver torque to at least one of the axles of the rear chassis.

The second electric motor may be coupled to deliver torque to each of the axles of the rear chassis.

The underground vehicle may further comprise a two speed transmission through which the second electric motor delivers torque to the axles of the rear chassis.

The second electric motor may be mounted on the second chassis and off centre of a centreline of the second chassis.

The underground vehicle may further comprise a suspension system coupled between the rear chassis and the axles of the rear chassis.

The underground vehicle may further comprise one or more batteries for storing electric energy, the batteries being electrically coupled to the electric motors wherein electric energy can be delivered to the motors from the batteries to provide torque to the axles, and the motors are arranged to act as generators at least when the truck travels down a decline to generate an electric energy that is delivered to and stored in the batteries.

The underground vehicle may further comprise an electric generator mechanically driven by the combustion engine, wherein the electric generator is electrically coupled to electric motors and the one or more batteries. A further aspect of the present invention provides an underground vehicle operable in an underground mine comprising: a front chassis and a rear chassis coupled together by an articulated joint; each chassis being provided with at least two axles; and a bin mounted on the rear chassis; and a combustion engine and first and second electric motors, wherein the combustion engine is electrically coupled to the first and second electric motors, the first electric motor coupled to deliver torque to at least one of the axles on the front chassis, and the second electric motor coupled to deliver torque to at least one of the axles of the rear chassis.

The underground vehicle may include a two-speed transmission through which the second electric motor delivers torque to the axles of the rear chassis.

The underground vehicle may further comprise an electric generator mechanically driven by the combustion engine, wherein the electric generator is electrically coupled to electric motors and the one or more batteries.

The bin preferably provides the underground truck has a load carrying capacity of between 70,000- 90,000 kg, inclusive. The underground truck may have dimensions to travel in an underground mine with a haulage path having a width and height of about 5.5m X 5.5m and traverse through 90° corners with wall clearance.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of the underground truck as set forth in the Summary, specific embodiments will now be described, by way of example only, with reference to becoming drawings in which:

Figure 1 is a schematic representation of an embodiment of the disclosed underground truck;

Figure 2 is a representation of the underground truck shown in Figure 1 but with its bin removed;

Figure 3 is a bottom view of the underground truck shown in Figure 2;

Figure 4 is a block diagram of a power plant and transmission system incorporated in the underground truck;

Figure 5 is a schematic representation of a front drive line incorporated in an embodiment of the underground truck; and

Figure 6 is a schematic representation of a rear drive line incorporated in an embodiment of the underground truck.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENTS

In the following detailed description, reference is made to accompanying drawings which form a part of the detailed description. The illustrative embodiments described in the detailed description, depicted in the drawings and defined in the claims, are not intended to be limiting. Other embodiments may be utilised and other changes may be made without departing from the spirit or scope of the subject matter presented. It will be readily understood that the aspects of the present disclosure, as generally described herein and illustrated in the drawings can be arranged, substituted, combined, separated and designed in a wide variety of different configurations, all of which are contemplated in this disclosure. With reference to the drawings an embodiment of the disclosed underground truck 10 (hereinafter “truck 10”) is a front chassis 12 and a rear chassis 14. The chassis 12 and 14 are coupled together by an articulated joint 16. The articulated joint 16 provides a single degree of freedom this being rotation about an axis 18 of the joint 16. Each chassis 12, 14 is provided with at least two axles. More specifically the front chassis 12 has two axles 20 and 22; the rear chassis 14 has two axles 24 and 26. A single wheel and tyre is coupled at each end of each axle. A bin 28 is supported on the rear chassis 14. The load of a fully laden bin 28 and the rear chassis 14 itself is carried by the four tyres coupled to the rear chassis. In one embodiment each of the chassis 12 and 14 is approximately 6 m in length with a maximum depth of approximately 1 ,5m ahead of the articulated joint 16; with a max width of about 3.5m and height of about 4.6m. An embodiment of the truck 10 with these dimensions (although other dimensions are possible for alternate embodiments) and the articulated joint 16, can travel in an underground mine with a haulage path having a width and height of about 5.5m X 5.5m and traverse through 90° corners with wall clearance. The bin may be dimensioned to have a water filled volume of 43.5 m³ and a SAE 2:1 heaped volume of 45 m³.

Typically, underground ore has a loose density of around 2 tonnes/m³ from an in-situ density of 2.3-2.4 tonne/m³. On this basis the embodiment of the disclosed truck 10 has a designed payload of up to 90,000 kg. Moreover, a viable working payload range for embodiments of the truck 10 is between 70, 000-90, 000kg, inclusive. In the particular embodiment described herein the nominal payload is 80,000kg.

The truck 10 is a hybrid diesel electric truck having a single combustion (diesel) engine 30 which is electrically coupled to a first electric motor 32 and a second electric motor 34. The first electric motor 32 is mounted on the front chassis 12 and coupled to the rear axle 22 by a single drive shaft. The second electric motor 34 is mounted on the rear chassis 14 and is coupled to drive both the axles 24 and 26. Also the second electric motor 34 is mounted off centre of a centreline of the second chassis.

The diesel engine 30 is mounted on the front chassis 12 and coupled via a transmission 36 to an electric generator 38. The generator 38 produces an AC current which passes through inverters 40 to a high-voltage distribution unit 42. The distribution unit 42 is coupled to: a battery pack 44 providing DC storage; the first electric motor 32 through a bank of inverters 46; and the second electric motor 34 through a bank of inverters 48.

A high-voltage electrical bus electrically couples the high-voltage distribution unit 42, the inverters 40, 46, and 48; the battery pack 44, and the motors 32 and 34 together.

By way of this configuration the driveline of the truck 10 is driven by electric motors 32 and 34 solely and there is no mechanical connection with the diesel engine. The diesel engine 30 drives the generator 38 which provides power to either the electric motors 32, 34 or the battery pack 44. The battery pack 44 may have a maximum capacity of 336 kwh. The inverters 40 and 46, battery pack 44, and distribution unit 42 are all supported on the front chassis 12. The battery pack 44 is located beneath a driver’s cab 50; with the diesel engine 30, transmission 36, generator 38, distribution unit 42, electric motor 32, and inverters 40, 46 all covered by a canopy 52.

The battery pack 44 acts as an energy reservoir. Whether the power produced by the diesel engine 30 and generator 38 is provided to the electric motors 32, 34 or the battery pack 44 by the distribution unit 42 during operation may be depend on the demand from each system and the task requirements.

The driveline of the truck 10 comprises three shafts 54, 56 and 58. The shaft 54 forms part of the front driveline and mechanically couples the electric motor 32 to the axle 22. More particularly one end of the drive shaft 54 is coupled to a single speed transmission 60 driven by the electric motor 32, and an opposite end of the drive shaft 54 provides torque to the axle 22 through a drive head/differential 62.

The rear driveline consists of the drive shafts 56 and 58. The drive shafts 56 and 58 transfer torque from the electric motor 34 to the axles 24 and 26 respectively. More particularly one end of the drive shaft 56 is coupled to a 2-speed transmission 66 driven by the electric motor 34, and an opposite end of the drive shaft 56 provides torque to the axle 24 through a drive head 66. The drive shaft 58 has one end mechanically coupled to the drive head 66 and an opposite end mechanically coupled to a drive head 68 which transmits torque from the shaft 58 to the axle 26. The provision of the two-speed transmission 66 gives the minimum number of gears required to produce a good start-ability on a 20% grade when the truck is fully laden. Also, this minimises mechanical complexity, enables the truck 10 to travel to a maximum speed of 25km/h. A further critical issue is the overall length of the truck 10 which impact on turning circle and the ability to turn through a 90° corner. The incorporation of addition gears would increase the length of the transmission/drive train and compromise overall tuck 10 length.

The drive shafts 54, 56 and 58 are aligned with the centreline of the truck 10. Because the second electric motor is mounted off centre of a centreline of the second chassis and the truck, the shaft 56 is not vertically stacked with the motor 32. This reduces overall head space needed to accommodate the motor 32, shaft 54; thereby giving more space for and thus volume to the bin 28.

The truck is provided with front and rear walking beam suspensions for the front and rear axles. The front and rear suspensions may use single acting hydro pneumatic cylinders to reduce the stiffness of the suspension and improved ride. Such suspension may also reduce the roll stiffness, which helps the amount of torsion load introduced into the respective front and rear chassis. The suspension stiffness for the chassis may be controlled by corresponding accumulator pre-charge and size.

When the truck 10 is travelling up a decline the diesel engine 30 and associated generator 38 provide electrical power to the high voltage electrical bus. The battery pack 44 also provides power to the bus. The two electric motors 32, 34 draw power from the bus and this provides the motive power. Therefore, provided the diesel engine 30 is running there will be electrical power being provided to the bus. The diesel engine 30 and generator 38 behave effectively as though they are a “diesel battery”. This power may be provided at a constant 750 Vdc. The battery pack 44 may be arranged to only provide power while it is charged or has a state of charge.

If the battery pack goes flat the truck 10 will still be able to drive, though its speed (about 50% of the maximum) will be limited to the power generated by the diesel engine 30 alone. Using the power of the diesel engine alone, an embodiment of the truck 10 will be capable of a laden hill start on a 20% grade.

In one embodiment the generator 38 may produce a nominal 490 kW of output at ambient temperature of about 50° C which may increase to 560 kW in cooler conditions of around 36°C to 40°C. The diesel engine 30 may have a maximum output of 532 kW. The battery may output up to 1008 kW.

Modelling shows that for a nominal design case of 14km/h on a 14% grade the required power is around 930 kW. If the maximum available power is applied to the electric motors 32, 34 a likely maximum achievable performance is around 18-19km/h when fully laden on 14% adverse grade.

When the truck 10 is travelling down the decline the diesel engine 30 continues to provide electrical power to the high voltage electrical bus. Additionally, the motors 32, 34 in the driveline change operating mode from motors to generators and supply power to the high voltage bus. The combined surplus power from these two processes charges the battery pack 44. If the battery pack 44 becomes fully charged during this time the truck 10 retardation may be provided using brakes (which may be wet brakes) associated with the each of the truck wheels.

In one embodiment of the truck 10 the axles 20, 22, 24 and 26 may be fitted with wheels having 750/65R25 tyres. These tyres have a diameter of about 1626mm, a width of about 765mm and rated at up to 18500 kg per tyre when inflated to 91 psi. The combined rating an embodiment of the truck 10 with eight such tyres is 148 tonnes. An embodiment of the disclosed truck 10 has an estimated tare weight of 50,000-54,000 kg. Therefore, with the additional payload of say 80,000 kg the combined load (130,000-134,000 kg) remains well within the combined rating of the eight tyres. Indeed, this gives scope to safely increase the payload beyond 80,000kg, and indeed up to 90,000 kg while providing a more than adequate safely margin form the max combined tyre rating of 148000 kg.

Embodiments of the disclosed truck 10 have several advantages over the current known prior art. These include a substantially increased payload and substantially reduced noxious emissions. The increased payload is due to a combination of features including the use of at least four axles and therefore at least eight tyres which by themselves facilitate a greater payload, but also because the tyres have a smaller diameter than those commonly used it is possible to mount a bin 28 having a greater volume/capacity.

The diesel-electric hybrid power plant which runs a smaller diesel engine than currently available comparable underground trucks reduces the volume of noxious fumes emitted into the underground mine thereby enhancing health and safety aspects for all workers in the mine. The shortfall in the diesel engine power is made up by the provision of power to the two electric motors by the battery.

When truck 10 is going down a decline the primary purpose of the diesel generator is to charge the battery pack 44 so the diesel engine 30 load is minimal therefore there is minimal fuel burn and minimal emissions. During the decline travel the battery pack 44 is simultaneously charged by the regeneration power from the electric motors 32, 34 (now acting as generators) motors as the truck is held at a constant speed.

In the claims which follow, and in the preceding description, except where the context requires otherwise due to express language or necessary implication, the word “comprise” and variations such as “comprises” or “comprising” are used in an inclusive sense, i.e. to specify the presence of the stated features but not to preclude the presence or addition of further features in various embodiments of the system and method as disclosed herein.

Claims

1. An underground vehicle operable in an underground mine comprising: a front chassis and a rear chassis coupled together by an articulated joint; each chassis being provided with at least two axles; and a bin mounted on the rear chassis; wherein the bin provides the underground truck has a load carrying capacity of up to at least 90,000 kg.

2. The underground truck according to claim 1 comprising a combustion engine and first and second electric motors, wherein the combustion engine is electrically coupled to the first and second electric motors, the first electric motor coupled to deliver torque to at least one of the axles on the front chassis, and the second electric motor coupled to deliver torque to at least one of the axles of the rear chassis.

3. The underground truck according to claim 2 wherein the second electric motor is coupled to deliver torque to each of the axles of the rear chassis.

4. The underground truck according to claim 2 or 3 comprising a two speed transmission through which the second electric motor delivers torque to the axles of the rear chassis.

5. The underground vehicle according to any one of claims 2-4 wherein the second electric motor is mounted on the second chassis and off centre of a centreline of the second chassis.

6. The underground vehicle according to any one of claims 1-5 comprising a suspension system coupled between the rear chassis and the axles of the rear chassis.

7. The underground vehicle according to any one of claims 2-6 comprising one or more batteries for storing electric energy, the batteries being electrically coupled to the electric motors wherein electric energy can be delivered to the motors from the batteries to provide torque to the axles, and the motors are arranged to act as generators at least when the truck travels down a decline to generate an electric energy that is delivered to and stored in the batteries.

8. The underground vehicle according to claim 7 comprising an electric generator mechanically driven by the combustion engine, wherein the electric generator is electrically coupled to electric motors and the one or more batteries.

9. An underground vehicle operable in an underground mine comprising: a front chassis and a rear chassis coupled together by an articulated joint; each chassis being provided with at least two axles; and a bin mounted on the rear chassis; and a combustion engine and first and second electric motors, wherein the combustion engine is electrically coupled to the first and second electric motors, the first electric motor coupled to deliver torque to at least one of the axles on the front chassis, and the second electric motor coupled to deliver torque to at least one of the axles of the rear chassis.

10. The underground truck according to claim 9 wherein the second electric motor is coupled to deliver torque to each of the axles of the rear chassis.

11 . The underground truck according to claim 9 or 10 comprising a two-speed transmission through which the second electric motor delivers torque to the axles of the rear chassis.

12. The underground vehicle according to any one of claims 9-11 wherein the second electric motor is mounted on the second chassis and off centre of a centreline of the second chassis.

13. The underground vehicle according to any one of claims 9-12 comprising a suspension system coupled between the rear chassis and the axles of the rear chassis.

14. The underground vehicle according to any one of claims 9-13 comprising one or more batteries for storing electric energy, the batteries being electrically coupled to the electric motors wherein electric energy can be delivered to the motors from the batteries to provide torque to the axles, and the motors are arranged to act as generators at least when the truck travels down a decline to generate an electric energy that is delivered to and stored in the batteries.

15. The underground vehicle according to claim 14 comprising an electric generator mechanically driven by the combustion engine, wherein the electric generator is electrically coupled to electric motors and the one or more batteries.

16. The underground vehicle according to any one of claims 1-15 wherein the bin provides the underground truck has a load carrying capacity of between 70,000- 90,000 kg, inclusive.

17. The underground vehicle according to any one of claims 1-16 wherein the truck is dimensioned to travel in an underground mine with a haulage path having a width and height of about 5.5m X 5.5m and traverse through 90° corners with wall clearance.