Electric agricultural tractor

Abstract

The invention relates to an electric agricultural tractor (1) comprising a front axle (10) and a rear axle (20), a chassis (30) connected to said axles, at least one power auxiliary (40, 42), means for electrically driving the axles and the power auxiliary, said means being powered by an electric power supply battery (60), said tractor comprising electric drive means comprising respective independent electric drives (2a, 2b, 2c) of the front axle (10), the rear axle (20) and at least one power auxiliary (40, 42); a chassis (30) comprising a hollow body (31), said chassis (30) extending in a longitudinal direction; a structural electric power supply battery (60) extending in the hollow body of said chassis, the hollow body (31) defining a mechanical casing of said battery.

Description

[0001] DESCRIPTION

[0002] TITLE OF THE INVENTION: ELECTRIC AGRICULTURAL TRACTOR

[0003] Technical field of the invention

[0004] The invention relates to an electric agricultural tractor. More particularly, the invention relates to a fully electric electric agricultural tractor whose energy needs are supplied by an electric power supply battery.

[0005] Technological background

[0006] In an agricultural context where field work has been greatly facilitated by the development of agricultural machinery, the use of thermal agricultural tractors, widely acclaimed by farmers, will now have to face the challenge of ecological transition.

[0007] More environmentally friendly approaches tend to move away from using fossil fuels as the sole fuel source, with more and more agricultural machinery using hybrid technology that combines fossil fuels and electrical power.

[0008] Most of these machines use a chassis with a classic load-bearing structure incorporating the "thermal engine - transmission shaft - gearbox" triad which has proven itself for more than a century.

[0009] Some agricultural concepts have been developed around fully electric operation. The vehicle is then powered by a battery attached to the tractor or by an additional structure installed on it. The thermal engine is thus replaced by an electric motor and a battery, but these concepts retain the classic transmission architecture that does not allow the integration of a sufficient battery volume. In addition, the retention of a traditional agricultural gearbox, designed for the operating speed of the diesel engine with numerous ranges and ratios, does not allow the wide operating range of the electric motor to be exploited compared to a diesel engine, the latter having a much more restricted operating range.

[0010] The energy demand of a fully electric agricultural tractor remains a limiting factor and the batteries offered do not allow it to compete with thermal tractors.

[0011] Most proposed electrifications include additional structures added to the classic tractor architecture. These structures have the disadvantage of making the vehicle heavier, but they can also complicate the arrangement of the tractor's mechanical or hydraulic components.

[0012] The electrification of agricultural tractors does not make it possible to significantly break with the traditional structure of thermal tractors while allowing the arrangement of a battery offering the best compromise between operating autonomy and tractor size.

[0013] An electric agricultural machine must be able to have a large capacity and large volume battery in order to benefit from satisfactory autonomy, however adjustments in terms of weight and equipment must be necessary to compensate for the installation of this large battery because the classic layout of the tractor elements does not allow for the optimization of the space necessary for the arrangement of a large volume battery. In addition, the agricultural tractor must meet specific and strict regulatory constraints that do not allow the chassis to be extended at will, to which are added constraints of maneuverability and vehicle height. The large volume layout must therefore not be at the expense of the compactness of the agricultural vehicle.

[0014] Document CN113752814 is known from the prior art, which describes a fully electric tractor with a battery arranged on the chassis and occupying the central space of the vehicle. However, this document describes a battery arranged and fixed on a support surmounting the chassis, which has the disadvantage of making the vehicle heavier. In addition, previous solutions retain in most cases the transmission shafts between the gearbox, the power take-off (PTO), the front axle, the rear axle and the gearbox housings, which are load-bearing and bulky elements of the central space of the tractor.

[0015] There is therefore a need to provide a fully electric agricultural tractor capable of overcoming the above issues.

[0016] Objectives of the invention

[0017] The invention aims to provide an electric agricultural tractor with an architecture optimized for the integration of a large capacity battery.

[0018] The invention also aims to provide, in at least one embodiment, an electric agricultural tractor capable of competing with a thermal agricultural tractor.

[0019] The invention also aims to provide, in at least one embodiment, an electric agricultural tractor with a structure allowing simplified mounting of a long-range electric battery.

[0020] The invention also aims to provide, in at least one embodiment, a compact electric agricultural tractor, freeing itself from the classic architecture of thermal tractors while being capable of withstanding the mechanical constraints inherent in its use.

[0021] The invention also aims to provide, in at least one embodiment, an electric agricultural tractor offering a better compromise between size and battery life.

[0022] The invention also aims to provide, in at least one embodiment, an electric agricultural tractor benefiting from better energy efficiency.

[0023] The invention also aims to provide, in at least one embodiment, an electric tractor whose power battery withstands the stresses coming from the axles.

[0024] The invention also aims to provide, in at least one embodiment, an electric agricultural tractor whose chassis and battery architecture makes it possible to do without additional structures that make the vehicle heavier.

[0025] Throughout the following description of the invention, the terms "tractor" and "agricultural tractor" must be interpreted equivalently and all relate, unless explicitly stated otherwise, to an agricultural work machine intended primarily for transport and traction, as well as for working the soil.

[0026] An aim of the present invention is to overcome the drawbacks of the prior art, to do this, the invention relates to an electric agricultural tractor comprising a front axle and a rear axle, a chassis mechanically connected to said axles, at least one power auxiliary, means for electrically driving the axles and the power auxiliary, said means being powered by an electrical power supply battery.

[0027] The tractor according to the invention further has the following technical characteristics: said electric drive means comprise independent electric motors respectively of the front axle, the rear axle and at least one power auxiliary; said chassis forms a hollow body defining a space having transverse walls including at least one perforated wall, said chassis extending in a longitudinal direction; said electric power battery is a structural battery forming an integral part of said chassis, said battery extending in said hollow body of said chassis and filling the space defined by said hollow body, said hollow body further defining a mechanical envelope of said battery so that the mechanical stresses applied to said chassis are partly supported by said battery of the electric tractor.

[0028] The inventors have thus developed an electric agricultural tractor that frees itself from the bulk inherent in the presence of the elements of the conventional frame of a tractor in order to free up a central space available for the arrangement of a large volume electric battery. Known electric tractors do not offer a structural battery to absorb the stresses exerted on the tractor. The tractor according to the invention allows the integration of a structural battery that is an integral part of the chassis and offers a better compromise between tractor size and autonomy.

[0029] For the purposes of the invention, the term "electric agricultural tractor" means an agricultural tractor powered by one or more electric drive means comprising electric motors. These means are powered by at least one electric power supply battery.

[0030] The electric drive means comprise both the tractor's powertrain and the motors associated with the tractor's various equipment. The tractor according to the invention thus comprises a decoupled electric motor.

[0031] By decoupling of electric motors is meant, within the meaning of the present invention, the presence of several electric motors which can be used to drive the axles and / or the various equipment and tools of the tractor. According to the invention, the motorization is thus plural and can be unbundled within the vehicle.

[0032] It should be defined for the purposes of the invention that the terms “hollow body” and “main hollow body” must be interpreted in the same way and define the main part of the chassis.

[0033] According to the invention, the front and rear axles of the tractor comprise an independent and respective electric motor. The motors of said axles are thus located as close as possible to the wheels. Each axle can therefore comprise a motor assigned to each of the wheels.

[0034] In a preferred mode, the tractor can have four drive wheels powered by four separate electric motors. This way, the engine's torque is transmitted to each wheel while eliminating the need for a mechanical differential used to distribute torque between the wheels on the same axle.

[0035] The tractor according to the invention also comprises an independent and respective electric motorization of a power auxiliary. The term "power auxiliary" can be defined as mechanical or hydraulic systems capable of transmitting the torque of an engine to different elements or various tools equipping the tractor. By independent and respective motorization, according to the invention, is meant a motorization assigned to a specific function of a motorizable element of the tractor.

[0036] Thus, independent motorization of at least one power auxiliary means a motorization assigned to at least one power auxiliary, said motorization being capable of transmitting the engine torque to one or more power auxiliaries.

[0037] In this respect, power auxiliaries may include power take-offs known under the English name "Power Take-Off" (PTO), hydraulic pumps or even hydraulic units used for internal tractor functions such as steering, braking, lubrication, but also units used for external functions such as lifting loads and tools, and transmitting power to tools.

[0038] Advantageously and according to the invention, the decoupling of the motors allows the elimination of transmission kinematics, and the electric motors make it possible to limit torque losses and thus increase energy efficiency while freeing up available space for the installation of a large volume battery.

[0039] The tractor also comprises a longitudinally extending chassis, said chassis being mechanically connected to the front and rear axles. For the purposes of the invention, the terms "front" and "rear" are terms of opposite location relative to the direction of the chassis.

[0040] According to the invention, the chassis forms a main hollow body extending longitudinally over all or part of the length of said chassis. Said hollow body also has walls, at least one of which is perforated, said walls delimiting an internal space of the chassis capable of accommodating a battery for supplying electricity to the tractor. The chassis of the tractor according to the invention may also comprise other structures mechanically connected to the hollow body of said chassis, these structures may in particular serve as additional reinforcement or extension making it possible to connect the axles to the chassis.

[0041] For the purposes of the invention, the term “openwork wall” should be defined as opposed to a solid wall.

[0042] Advantageously, the use of at least one openwork wall makes it possible to lighten the weight of the chassis while allowing the passage of the vehicle's wiring.

[0043] Preferably, the hollow body comprises at least two walls, said walls being arranged transversely opposite one another relative to the longitudinal direction of the chassis.

[0044] For the purposes of the invention, the term “internal space of the chassis” means a space framed and delimited by all the structural elements of the chassis forming the hollow body. The structural elements of the chassis are elements comprising materials having a high inertia and capable of constituting the structure of the hollow body, such as, for example, corner pieces, side members, profiled posts or even cross members. The materials are those known to those skilled in the art and may, for example, be chosen from metals, alloys, carbon or their mixture.

[0045] The assembly and connection of the various structural elements of the chassis can be carried out using techniques known to those skilled in the art, in particular by mechanical welding or any other suitable means of fixing or connection.

[0046] The tractor according to the invention also comprises an electrical power supply battery. By electrical power supply battery is meant a lithium-ion type accumulator battery or a battery comprising any other cell chemistry having a mass and volume energy density sufficient to achieve the energy objectives of the tractor of between 200kWh and 1000kWh.

[0047] According to the invention, the battery is arranged and fixed in the hollow body of the chassis so as to extend in the direction of said hollow body and to occupy all or part of the internal space defined by the latter. The electrical power supply battery thus arranged makes it possible to fill the internal space defined by the walls of the hollow body of the chassis. By filling the internal space, we mean an occupation of the internal space or the volume of the hollow body by the battery greater than or equal to 80% of said internal space, in which at least a portion of the battery is in direct or indirect contact with the hollow body.

[0048] Advantageously, the hollow body forms a mechanical envelope for the battery so that the mechanical stresses applied to the electric chassis are partly supported by the battery, said battery thus forming an integral part of the chassis and contributing to reinforcing the structure of the chassis and supporting the forces transmitted by the axles or by the use of the tools fitted to the tractor.

[0049] For the purposes of the invention, it is understood that the mechanical stresses applied to the tractor correspond to all the forces undergone by the chassis and in particular by the combination of the chassis and the structural battery when said tractor is at rest or in operation, in particular when moving or during the execution of a task.

[0050] More generally, the architecture of the electric agricultural tractor according to the invention is based on a battery chassis. This means that the chassis is formed at least in part by said structural battery and that the chassis of the tractor is a combination of structural elements of the chassis and the battery. Thus, the tractor according to the invention can be distinguished from other electric tractors in the sense that it does not have a chassis supporting the battery.

[0051] This particular arrangement of the electric tractor according to the invention also makes it possible to better distribute the weight of the tractor, in particular with a structural battery forming the chassis, and to free itself from the addition of an additional structure aimed at integrating a large-volume battery on a conventional supporting chassis. Consequently, the invention makes it possible to optimize the ratio between a long-range battery and therefore a large volume, and the weight of the tractor. In this respect, it should be noted that a tractor according to the invention, without a battery, cannot withstand the stresses transmitted by the tractor wheels in particular. The structural battery is an integral part of the chassis and is one of the essential elements making it possible to withstand the stresses undergone by the tractor.The structural battery is preferably arranged centrally in the chassis and can thus allow more stability and maneuverability in work maneuvers, in particular by allowing greater angles to be obtained for the rotation of the steered wheels.

[0052] For the purposes of the invention, the term mechanical envelope means an external structure formed by structural elements of high inertia, said structure forming a hollow body.

[0053] The electric agricultural tractor according to the invention therefore has the particularity of having a design allowing the installation of a large structural battery, this design allows, with the decoupling of the electric drive means, the optimization of the space available for the arrangement of said structural battery in the chassis to benefit from a larger volume electric power supply battery offering greater autonomy.

[0054] Furthermore, the electric agricultural tractor according to the invention has a novel arrangement where the power battery helps to reinforce the chassis.

[0055] Advantageously and according to the invention, the hollow body further comprises a lower wall defining a base and an upper wall defining a ceiling, said base and ceiling extending parallel opposite one another and being respectively formed by longitudinal angles connected by crosspieces.

[0056] The base and the ceiling are similar to walls and are each formed by a pair of longitudinal angles connected transversely by crosspieces, each of the pairs of angles of the hollow body being spaced apart and arranged parallel to each other. Preferably, the hollow body comprises at least four longitudinal angles, with a ceiling and a base comprising two angles respectively.

[0057] Thus, and according to this advantageous variant, the angle iron wings make it possible to block the battery and preserve the integrity of the battery modules at the edges of the battery pack. Advantageously and according to the invention, the hollow body is of parallelepiped shape and said longitudinal angles have ends integral with the transverse walls.

[0058] Thus, and according to this advantageous variant, the hollow body of the chassis forms a mechanical envelope of the battery providing a distribution of the mechanical stresses supported by the battery in all directions.

[0059] Advantageously and according to the invention, the chassis further comprises side plates secured to the base.

[0060] The side plates thus represent another part of the chassis with reference to the hollow body. According to this variant, the chassis thus comprises the hollow body and the side plates.

[0061] Thus, and according to this advantageous variant, the tractor according to the invention makes it possible to exploit the maximum available central space of the vehicle for the arrangement of a large volume and greater capacity battery.

[0062] Advantageously and according to the invention, the base of the hollow body and the side plates further comprise a floor having profiled crosspieces on which said battery is mounted.

[0063] Preferably, the floor may comprise insulating materials. The insulating materials that may be used may be chosen from materials with high thermal resistance, waterproof materials and / or any other material known to those skilled in the art. The insulating materials may be arranged on all the walls and structures surrounding the battery in order to maintain it at an ideal operating temperature and to benefit from greater autonomy.

[0064] Thus, and according to this advantageous variant, this arrangement makes it possible to transfer the rigidity of the structure to the battery and to better transmit the constraints applied to the tractor.

[0065] Advantageously and according to the invention, the power battery further extends over the side plates, said battery being a single piece. According to this variant, the battery may extend over all or part of the respective surfaces of the side plates. When the battery is thus arranged, a lateral span may also be provided in the structure of the battery so that the latter can adopt the shape of the corners of the base. It may also be provided that a portion of the corner of the base can be adapted to the shape of the battery so as not to obstruct the latter. In addition, each of the side blocks may extend over all or part of the surface of a side plate.

[0066] Thus, and according to this advantageous variant, the intrinsic weight of the battery is better distributed over the central space of the tractor and allows it to be balanced.

[0067] Advantageously and according to the invention, the battery further extends over the side plates, said battery being formed by a plurality of blocks, including at least one central block extending into the hollow body and two side blocks arranged on the side plates.

[0068] Preferably, the battery is formed of three blocks including a central block extending into the hollow body and two lateral blocks arranged on the lateral plates of said chassis, said lateral blocks being connected to the central block.

[0069] Thus, according to this advantageous variant, the modular integration of the battery blocks makes it possible to simplify the installation of the latter in the chassis while offering a larger battery volume.

[0070] Advantageously and according to the invention, each side plate comprises vertical posts arranged laterally against the hollow body of the chassis, said posts respectively comprising two ends, with a first end, called the lower end, connected to an angle iron of the base of the chassis, and a second end, called the upper end, connected to an angle iron of the ceiling of the chassis.

[0071] Preferably, the vertical posts are profiled and have a height at least equivalent to the height of the hollow body. Thus and according to this advantageous variant, the electric agricultural tractor of the invention benefits from a structural battery whose integrity is preserved by the arrangement of the different structural elements.

[0072] Advantageously and according to the invention, the vertical posts further comprise a strut resting on at least a portion of the surface of a side plate.

[0073] Thus, and according to this advantageous variant, the tractor chassis can better support the arrangement of a large volume electric battery with a significant weight.

[0074] Advantageously and according to the invention, the frame comprises removable mechanical connections connecting the upper end of a vertical post with an angle iron of the ceiling of said frame.

[0075] Thus, and according to this advantageous variant, the chassis structure can be mounted in two parts to facilitate the arrangement of the structural battery.

[0076] Advantageously and according to the invention, the tractor comprises directional axles.

[0077] Thus, according to this advantageous variant, the tractor benefits from a constant chassis width along the hollow body, such a steering system also makes it possible to minimize the steering angle of the wheels to optimize the space available on the side platforms. The steered axles also make it possible to reduce steering efforts when turning the tractor.

[0078] The electric agricultural tractor according to the invention may also include closing sheets capable of covering the chassis to improve its rigidity. The closing sheets may also contribute to the insulation of the battery by integrating insulation elements.

[0079] According to the invention, it is also possible to provide a range extender for said battery. Indeed, during work with high energy consumption, the tractor is ballasted on the front linkage to increase traction efficiency. The range extender can thus be arranged in place of the ballast in order to further increase the vehicle's range. The range extender can thus comprise a battery module.

[0080] Furthermore, with the range extender, the invention makes it possible, while remaining within the average wheelbase, turning radius and height of known vehicles, to reach and exceed an on-board energy stored in the battery corresponding to the criterion C>5P, with C corresponding to the on-board energy expressed in kWh, P corresponding to the nominal motor power expressed in kW.

[0081] According to the invention, the agricultural tractor may also include a recharging system enabling it to operate in regenerative mode.

[0082] All of the characteristics of the electric agricultural tractor according to the invention make it possible to propose a tractor comprising a central space optimized for the arrangement of a large capacity electric battery capable of meeting the functional energy needs of an agricultural tractor during a working day.

[0083] With integrated electrification and a structural battery forming an integral part of the chassis, the fully electric agricultural tractor of the invention frees itself from the classic framework of known tractors, notably with the elimination of a carrier gearbox normally located under the cab and the reduction of the space and weight dedicated to classic mechanical transmission elements.

[0084] The invention also relates to an electric agricultural tractor characterized in combination by all or part of the characteristics mentioned above or below.

[0085] List of figures

[0086] Other aims, characteristics and advantages of the invention will appear on reading the following description given solely for non-limiting purposes and which refers to the appended figures in which: - [Fig. 1] is a schematic view representing the lower part of the chassis comprising the hollow body and side plates according to one embodiment of the invention.

[0087] - [Fig. 2] is a schematic view showing an arrangement of the electric power supply battery in the tractor according to one embodiment of the invention.

[0088] - [Fig. 3] corresponds to a schematic view representing a cross-section of the mechanical casing of the battery according to one embodiment of the invention.

[0089] - [Fig. 4] is a simplified schematic view of the tractor according to one embodiment of the invention.

[0090] Detailed description of an embodiment of the invention

[0091] In the figures, scales and proportions are not strictly respected, for the purposes of illustration and clarity.

[0092] Identical, similar or analogous elements are designated by the same references in all figures.

[0093] Throughout the following detailed description with reference to the figures, unless otherwise indicated, each element of the electric agricultural tractor is described as it is arranged in said tractor.

[0094] The tractor 1 comprises a front axle 10, a rear axle 20, a chassis 30 mechanically connected to the axles 10 and 20, a power auxiliary 40, 42, means for electrically driving the axles 10 and 20 and at least one power auxiliary 40, 42, said means being powered by an electrical power supply battery 60. More precisely, the tractor 1 comprises electrical drive means corresponding to independent and electric motors 2a, 2b and 2c. The electric motors 2a, 2b and 2c can be respectively assigned to the front axle 10, to the rear axle 20 and to a power auxiliary 40, 42.

[0095] The tractor according to the invention comprises a chassis 30 extending in a longitudinal direction. Said chassis 30 comprises a hollow body 31 having perforated walls 32a and 32b arranged transversely opposite one another with respect to the longitudinal direction of the chassis, said direction being comparable to that of the hollow body 31. The hollow body 31 and the walls 32a and 32b define an internal space 33 intended to house an electric power supply battery 60. In addition, the chassis 30 may comprise other structural elements annexed and connected to the hollow body 31, such as side plates 34a and 34b, or even extensions used to connect the axles 10 and 20 of the tractor 1.

[0096] The power supply battery 60 is a structural battery housed within the hollow body 31 and which occupies and fills the entire space 33 defined by the latter. In addition, the hollow body 31 comprises a lower wall defining a base 31a and an upper wall defining a ceiling 31b. The base 31a and the ceiling 31b are arranged parallel to each other and facing each other, each of the walls forming said base 31a and said ceiling 31b being respectively located on two parallel planes extending longitudinally in the direction of the hollow body 31. Said hollow body 31 thus comprises a base 31a, a ceiling 31b, transverse walls 32a and 32b which, arranged together, define an internal space 33 intended to house a power supply battery 60.

[0097] This particular arrangement of the battery 60 thus allows said battery to absorb at least part of the mechanical stresses coming from the axles 10 and 20 and transmitted to the battery by the chassis 30. In other words, the battery is structural and forms part of the chassis. The battery not only has a larger volume and a larger capacity thanks to the freed up space but also contributes to the structural rigidity of the chassis 30 of the tractor 1 of the invention.

[0098] Figure 1 illustrates a lower portion of the chassis 30 of the tractor 1 according to an embodiment of the invention where the hollow body is parallelepiped in shape. In this figure, the base 31a of the hollow body 31 is formed by a pair of lower longitudinal angles 35a. The base 31a may also comprise crosspieces 36a transversely connecting the angles 35a. Each of the ends of the longitudinal angles 35a being respectively connected to a lower portion of the transverse walls 32a and 32b, said walls 32a and 32b being arranged transversely and orthogonally to the lower longitudinal angles 35a. In this figure, the chassis 30 also comprises side plates 34a and 34b extending transversely relative to the direction of the hollow body 31.The lateral plates 34a and 34b are arranged laterally to the base 31a and respectively secured to a lower longitudinal angle iron 35 forming the base 31a of the hollow body 31.

[0099] In this embodiment, each of the plates 34a and 34b comprises vertical posts 37 connected laterally against the angles 35a of the hollow body 31. In addition, each of the vertical posts 37 is profiled and held in abutment against the hollow body 31 by means of struts 39, said struts being connected on the one hand to a portion of a post 37 and, on the other hand to a portion of the surface of a lateral plate 34a or 34b. Each post 37 comprises a lower end 37a and an upper end 37b. The posts 37 further comprise orifices 38 arranged on their upper end 37b, said orifices 38 are placed inside the profile of each of the posts 37, thus being able to receive removable connecting means for connecting a ceiling 31b of the hollow body 31 as shown in FIG. 2.

[0100] Figure 2 illustrates the arrangement of an electrical power supply battery 60 of the tractor 1 according to one embodiment.

[0101] In the embodiment shown, the battery 60 is a single-piece battery filling the internal space 33 of the hollow body 31 of parallelepiped shape. The hollow body 31 comprises a ceiling 31b formed by upper longitudinal angles 35b. Said ceiling 31b is arranged opposite the base 31a of the hollow body 31. In order to further increase the rigidity of the structure, the angles 35b are connected transversely by crosspieces 36. In this figure, the battery 60 further extends over a portion of the respective surface of the side plates 34a and 34b. Furthermore, when the battery 60 does not extend over the entire surface of a side plate 34, a lateral space can be provided for the arrangement of additional related elements or accessories of the tractor 1. The single-piece battery 60 as shown in FIG. 2 comprises spans 61 making it possible to span a portion of the longitudinal angles 35a of the base 31a.In the embodiment shown in this figure, the volume of the battery 60 comprises a height substantially equal to the height of the hollow body 31 and the posts 37 of the side plates 34a and 34b. The posts 37 respectively comprise a lower part 37a connected to an angle iron 35a and an upper end 37b connected to an angle iron 35b.

[0102] In this figure, the hollow body 31 and the side plates 34a and 34b comprise a floor 70. The floor 70 comprises profiled crosspieces 71 on which the battery 60 is fixed. The base 31a is thus completely covered by the floor 70 and the lower surface of the battery 60 rests on the profiled crosspieces 71 of the floor 70. In other words, the floor 70 and the profiled crosspieces 71 extend under the entire surface occupied by the electrical power supply battery 60 except at the level of the crossings 61.

[0103] Figure 3 schematically illustrates the structural arrangement of the hollow body 31 of the chassis 30 according to one embodiment. This figure represents a cross-section of the hollow body 31 without the walls 32a and 32b.

[0104] In this figure, the battery 60 substantially covers the entire internal space 33 of the hollow body 31 and is embedded in each of the angles 35a and 35b of the base 31a and the ceiling 31b. In this embodiment, crosspieces 36a and 36b respectively connect the pairs of angles 35a and 35b. The posts 37 laterally connect the angles 35a and 35b. For the sake of simplification, the side plates 34a and 34b and the struts 39 have not been shown.

[0105] Figure 4 shows a schematic view of the tractor 1 according to one embodiment of the invention. In this embodiment, the chassis 30 comprises the hollow body 31, the side plates 34a and 34b, but also an extension 30b to which the front axle 10 is mechanically connected. The extension 30b is connected to the hollow body 31 via the transverse wall 32b and extends longitudinally in the direction of said hollow body 31. Furthermore, an extension similar to the extension 30b can also serve to mechanically connect the rear axle 20 via the transverse wall 32a of the tractor 1 but has not been shown for the sake of clarity. The axles 10 and 20 of the tractor 1 are also steered axles.

[0106] In this figure, the tractor 1 comprises electric drive means embodied by the electric motors 2a, 2b and 2c respectively and independently driving the front axle 20, the rear axle 10 and power auxiliaries 40, 42. In the embodiment shown, the motor 2c is connected to a hydraulic pump 40 and to a power take-off (PTO) 42 via a reducer 41 comprising an input connected to the motor 2c and two outputs respectively transmitting the torque from the motor 2c to the pump 40 and to the power take-off 42. The power auxiliaries represented by the pump 40 and the power take-off 42 are thus powered by the same electric motor 2c, although the invention can also provide a respective motorization independent of the power auxiliaries 40 and 42.According to this embodiment, the front axle 10 is driven by the motor 2a arranged centrally on said axle 10 and the rear axle 20 is driven by the motor 2b adjacent to the motor 2c, said motors 2b and 2c being arranged centrally on the rear axle 20.

Claims

CLAIMS 1. Electric agricultural tractor (1) comprising a front axle (10) and a rear axle (20), a chassis (30) mechanically connected to said axles (10, 20), at least one power auxiliary (40, 42), means for electrically driving the axles (10, 20) and at least one power auxiliary (40, 42), said means being powered by an electrical power supply battery (60), said tractor (1) being characterized in that: said electric drive means comprise independent electric motors (2a, 2b, 2c) respectively of the front axle (10), of the rear axle (20) and of at least one power auxiliary (40, 42); said frame (30) forms a hollow body (31) defining a space (33) having transverse walls (32a, 32b) including at least one perforated wall, said frame (30) extending in a longitudinal direction;said power supply battery (60) is a structural battery forming an integral part of said chassis, said battery extending into said hollow body (31) of said chassis (30) and filling the space (33) defined by said hollow body (31), said hollow body (31) defining a mechanical envelope of said structural battery (60) so that the mechanical stresses applied to said chassis are partly supported by said battery (60).; 2. Tractor according to claim 1, characterized in that the hollow body (31) further comprises a lower wall defining a base (31a) and an upper wall defining a ceiling (31b), said base (31a) and ceiling (31b) extending parallel opposite one another and being respectively formed by longitudinal angles (35a, 35b) connected by crosspieces (36).

3. Tractor according to claim 2, characterized in that the hollow body (31) is of parallelepiped shape and in that said longitudinal angles (35a, 35b) have ends integral with the transverse walls (32a, 32b).

4. Tractor according to claim 3, characterized in that the chassis (30) further comprises side plates (34a, 34b) integral with said base (31a).

5. Tractor according to claim 4, characterized in that said base (31a) of the hollow body (31) and said side plates (34a, 34b) further comprise a floor (70) having profiled crosspieces (71) on which said battery (60) is mounted.

6. Tractor according to one of claims 4 to 5, characterized in that the supply battery (60) further extends over the side plates (34a, 34b), said battery being in one piece.

7. Tractor according to one of claims 4 to 5, characterized in that the battery (60) further extends over the side plates (34a, 34b), said battery (60) being formed from a plurality of blocks, including a central block extending into the hollow body (31) and two side blocks arranged on the side plates (34a, 34b).

8. Tractor according to one of claims 6 or 7 characterized in that each side plate (34a, 34b) comprises vertical posts (37) arranged laterally against the hollow body (31) of the chassis (30), said posts (37) respectively comprising two ends (37a, 37b), with a first end, called the lower end (37a), connected to an angle iron (35a) of the base (31a), and a second end, called the upper end (37b), connected to an angle iron (35b) of the ceiling (31b).

9. Tractor according to claim 8, characterized in that the vertical posts (37) further comprise a strut (39) bearing on at least a portion of the surface of a side plate (34a, 34b).

10. Tractor according to claim 9 characterized in that the chassis comprises removable mechanical connections connecting the upper end (37b) of a post (37) with an angle iron (35b) of the ceiling (31b).

11. Tractor according to one of the preceding claims, characterized in that the axles (10, 20) are steered axles.

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