FR3134537A1 - Work machine with universal joint transmission - Google Patents

Abstract

The invention relates to a work machine (1) comprising a first axle (3), a transfer case (6) secured to the first axle (3) and configured to drive the first axle (3) and at least one electric motor ( 10) to drive the transfer case (6), in which said electric motor (10) drives the transfer case (6) via a reducer (9), the reducer (9) not being integral with the transfer case (6) or the first axle (3), the reduction gear (9) having an output shaft and the transfer case (6) having an input shaft, the output shaft being coupled to the input shaft via a transmission shaft (8), an axis of rotation of the transmission shaft (8) and an axis of rotation of the input shaft being non-parallel and intersecting, and the shaft of transmission (8) and the input shaft being coupled by means of a first universal joint (7, 71). Figure for abstract: Fig. 7

Description

Work machine with universal joint transmission

The invention relates to the field of work machinery. More particularly, the invention concerns the transmission of mechanical power to the wheels of the work machine.

Technology background

Work machines, in particular load handling machines, are generally equipped with a transmission system including at least one motor, the transmission system rotating drive wheels connected by an axle.

The integration of environmental considerations (reduction in greenhouse gas emissions) and regulatory constraints (for warehouse handling, for example) has led to the electrification of work vehicles.

US 2020/0406681 A1 describes an electric work machine equipped with an electric transmission, in which an axle is provided with an electric motor secured to an axle housing. A reduction gear and a transfer case are connected in series with the electric motor. The electric motor thus drives the axle via the reduction gear and the transfer case. On the other hand, the transfer case includes an output shaft and the output shaft of the transfer case is connected, via a Cardan joint, to a transmission shaft connecting the axle to a second axle of the machine of work.

However, to supply the electric motor with electricity, it is also necessary to position on-board batteries on board the work machine. An arrangement where the electric motor is attached to the axle is not always compatible with the desired positioning of the batteries, in particular with a configuration where batteries must be positioned in the middle of the chassis.

Summary

An idea underlying the invention is to allow freer positioning of an electric motor within the chassis of a work machine.

According to one embodiment, the invention provides a work machine comprising a first axle and a second axle, a transfer box secured to one of the first axle and the second axle and configured to drive the first axle and the second axle , and at least one electric motor for driving the transfer case, wherein said electric motor drives the transfer case via a reduction gear, the reduction gear having an output shaft and the transfer case having an output shaft input, the output shaft being coupled to the input shaft via a transmission shaft, an axis of rotation of the transmission shaft and an axis of rotation of the input shaft being non-parallel and intersecting, and the transmission shaft and the input shaft being coupled by means of a first universal joint.

The coupling described by means of a universal joint allows the reducer and the electric motor to be placed more freely within the chassis, in particular because the output shaft of the electric motor and the output shaft of the reducer do not need to be aligned with, or even close to, the transfer case input shaft. In other words, the electric motor and the reduction gear can be placed more freely, not being integral with the transfer case or the first axle or the second axle,

According to embodiments, such a work machine may include one or more of the following characteristics.

According to one embodiment, the work machine further comprises two spars parallel to each other and parallel to a central longitudinal axis of the work machine.

According to one embodiment, batteries used to power the electric motor are arranged between the spars.

Such a central position of the batteries ensures better mass distribution within the vehicle and also allows protection of the batteries against damage caused by impacts.

According to one embodiment, the gearbox and the transmission shaft are connected by a second universal joint.

According to one embodiment, the first universal joint and/or the second universal joint is a Cardan joint.

According to one embodiment, said electric motor is mounted on the reduction gear. According to one embodiment, the work machine further comprises a second electric motor also mounted on the reduction gear.

According to one embodiment, a rear end of the transmission shaft is further away from the central longitudinal axis than a front end of the transmission shaft.

Thus, the reduction gear and the electric motor can be placed eccentrically within the chassis, while not forcing the first universal joint to support too large an angle which would be detrimental to its lifespan.

According to one embodiment, the rear end of the transmission shaft is placed at height, in a vertical direction of the work machine, relative to the first axle.

This ensures that the driveshaft does not affect the ground clearance of the machine.

According to one embodiment, a first angle between the input shaft of the transfer case and the transmission shaft is equal to a second angle between the transmission shaft and the output shaft of the reduction gear.

Thus, the first universal joint and the second universal joint are constant velocity.

According to one embodiment, the first angle and the second angle add up to ensure maximum distance of the reducer relative to the central longitudinal axis.

According to one embodiment, a rotation speed of the input shaft of the transfer case and a rotation speed of the output shaft of the reduction gear are identical.

According to one embodiment, an inclination of the output shaft of the gearbox relative to the central longitudinal axis is greater than an inclination of the transmission shaft relative to the central longitudinal axis.

According to one embodiment, the gearbox and the electric motor are placed in a box, the box being fixed on a side face of the work machine, between the first axle and the second axle in a longitudinal direction of the work machine. work.

Thus, the gearbox and the electric motor can be protected against external shocks by the box, while remaining easily accessible due to the positioning of the box.

According to one embodiment, the box has closable flaps.

Thus, access to the gearbox and the electric motor is facilitated for maintenance operations and the gearbox and the electric motor can be protected against unauthorized interventions.

According to one embodiment, the box is raised, following the vertical direction of the work machine, relative to the first axle.

According to one embodiment, the reducer is placed in a rear half of the box following the longitudinal direction of the machine.

According to one embodiment, the work machine further comprises a hydraulic motor and a hydraulic pump used to operate a lifting arm.

According to one embodiment, the hydraulic motor and the hydraulic pump are placed in the box.

According to one embodiment, the box is fixed to one of the two spars.

According to one embodiment, the reducer is fixed to said spar by means of a fixing element.

According to one embodiment, a passage space between an interior face of the box and said longitudinal member communicates an interior of the box and an underside of the chassis.

According to one embodiment, the transmission shaft connects the reduction gear and the first axle through the passage space in the box.

According to one embodiment, the transmission shaft is positioned at least partially under the side members.

Brief description of the figures

The invention will be better understood, and other aims, details, characteristics and advantages thereof will appear more clearly during the following description of several particular embodiments of the invention, given solely by way of illustration and not limitation. , with reference to the attached drawings.

There is a perspective overview of a lifting machine.

There is a top view of the transmission of the lifting machine of the .

There is a side view of the transmission shown on the .

There is a schematic representation of the transmission shown in Figures 2 and 3, according to a variant.

There is a perspective view projected into plane D of the transmission shown on the and the .

There is a rear view of the transmission shown on the , there and the , together with the frame of the lifting machine.

There is a perspective view of the chassis of the lifting machine according to one embodiment.

There is a bottom view of the frame of the lifting machine of the .

There is an overall perspective view of a work machine, produced here in the form of a lifting machine 1. The lifting machine 1 comprises a chassis 2 and a lifting arm 20. The arrow AA represents an axis median front-rear axis of the lifting machine 1, aligned with the middle of a front axle 3 and a rear axle 4. The central front-rear axis corresponds to a longitudinal direction of the lifting machine 1.

An arrow B corresponds to a transverse direction of the lifting machine 1, defined as perpendicular to the longitudinal direction and belonging to a plane of the chassis 2.

An arrow C corresponds to a vertical direction of the lifting machine 1, defined as perpendicular to the longitudinal direction and the transverse direction.

The chassis 2 is mobile and movable on the surface of the ground (not shown), here by means of the front axle 3 carrying two front wheels 3A, one on the left and the other on the right, and the axle rear 4 carrying two rear wheels 4A, one on the left and the other right.

With reference to Figures 1 and 6 to 8, the chassis 2 comprises two longitudinal beams 30. The longitudinal beams 30 are metal parts parallel to each other and perpendicular to a transverse direction of the lifting machine.

The longitudinal members 30 extend between a front face and a rear face of the lifting machine 1 and are thin flat parts, placed perpendicular to a plane of the chassis 2.

In reference to the , the lifting arm 20 is articulated to the two spars 30, between the two spars 30, so as to be pivotally movable relative to the two spars 30 around a pivot axis P. The pivot axis P is in particular marked on the . The pivot axis P is parallel to the transverse direction of the lifting machine 1. The suitable means for making the lifting arm 20 movable to pivot are well known as such and are not described in detail here.

The lifting arm 20 can be produced in different ways, in particular in the form of several telescopic sections, or alternatively in the form of an arm of fixed length. One end of the lifting arm 20 opposite the pivot axis P can carry a work tool or, as shown in the , a modular tool holder capable of receiving two working tools of several types, according to known technique. By work tool, we mean for example a pair of forks, a bucket, a winch, a clamp, etc.

The lifting machine 1 further comprises a cabin 75 in which an operator of the lifting machine 1 can take place and a box 28 which can accommodate various equipment used for the operation of the lifting machine 1.

The cabin 75 is located on a first lateral side of the lifting machine 1 and the box 28 is located on a second lateral side of the lifting machine 1, the first lateral side and the second lateral side being on either side the other of the two longitudinal members 30 following the transverse direction of the lifting machine 1.

With reference to Figures 2 and 3, the front axle 3 and the rear axle 4 are connected by a connecting shaft 5 which is perpendicular to the front axle 3 and the rear axle 4.

A transfer case 6 is integral with the front axle 3. The transfer case 6 is connected to a transmission shaft 8 via a first Cardan joint 7. The transmission shaft 8 is further connected to a reducer 9 via a second Cardan joint 17 (not visible in Figures 2 and 3 but visible on the ).

The first Cardan joint 7 and/or the second Cardan joint 17 can be replaced by other types of universal joints, for example double Cardan joints or tripod joints.

The reducer 9 is integral with an electric motor 10 and a fixing element 11 is attached to the reducer 9, for example by means of bolts (not shown). The fixing element 11 can also be attached to a fixed part of the machine, such as for example a spar 30, in order to stabilize a position of the reduction gear 9 and the electric motor 10.

The transmission shaft 8 extends diagonally across one half of the chassis 2 delimited by the perpendicular connecting shaft 5. The transmission shaft 8 forms an acute angle with the input shaft of the transfer case 6, thanks to the mechanical connection made by the first Cardan joint 7.

The reduction gear 9 and the electric motor 10 are positioned eccentrically, on the same side of the shaft 5 in the transverse direction. According to a preferred embodiment, the reduction gear 9 is closer to the rear axle 4 than to the front axle 3.

In reference to the , the transmission shaft 8 is not placed in the plane of the front axle 3 and the rear axle 4. An elevation angle β between the transmission shaft 8 and the connecting shaft 5 is an acute angle making it possible to raise the reduction gear 9 and the electric motor 10 relative to the front axle 3 and the rear axle 4.

We represented on the a variant of the transmission shown in Figures 2 and 3. The transmission shaft 8 is linked to the transfer case 6 by a double Cardan joint 71. In addition, a first electric motor 101 and a second electric motor 102 are linked to the reduction gear 9. According to a preferred embodiment, the first electric motor 101 and the second electric motor 102 are arranged on either side of the reduction gear 9.

In reference to the , a first angle γ is defined and measured in the plane comprising the connecting shaft 5 and the transmission shaft 8. The first angle γ is defined as an angle between the input shaft of the transfer case 6 and the transmission shaft 8. The first angle γ corresponds to an angle of the first Cardan joint 7.

A second angle δ is defined and measured in the plane comprising the connecting shaft 5 and the transmission shaft 8. The second angle δ is defined as an angle between the transmission shaft 8 and the output shaft of the gearbox 9. The second angle δ corresponds to an angle of the second Cardan joint 17.

The second angle δ is oriented so as to increase the distance between the reducer and the connecting shaft 5. Thus, a total angle ε between the reducer 9 and the connecting shaft 5 is equal to a sum of the first angle γ and the second angle δ.

According to a preferred embodiment, the first angle γ and the second angle δ are equal, which makes it possible to guarantee a homokinetic speed between an output shaft of the reducer 9 and an input shaft of the transfer case 6.

The first angle γ and the second angle δ have a value preferably between 0° and 15°.

More preferably, the first angle γ and the second angle δ have a value between 11° and 15°.

According to a preferred embodiment, the first angle γ and the second angle δ have a value of 14° each.

Thus, according to a preferred embodiment, the total angle ε has a value of 28°.

The first angle γ, the second angle δ and the total angle ε being measured in an oblique plane, they each have a horizontal component and a vertical component. Thus, the first angle γ, the second angle δ and the total angle ε contribute both to eccentric the reducer 9 by moving it away from the connecting shaft 5, and to lifting the reducer 9 relative to the ground.

In particular, with reference to the , an angle θ is defined as an angle between the horizontal axis and an axis passing through a projection of the input shaft of the transfer case 6 and the output shaft of the reducer 9 in a plane comprising the horizontal axis and vertical axis.

The angle θ belongs to a range preferably between 15° and 40°. More preferably, the angle θ has a value between 25° and 35°. According to a preferred embodiment, the angle θ has a value of 30°. Such a value of θ makes it possible to improve the ground clearance of the lifting machine 1.

With reference to Figures 7 and 8, the lifting machine 1 comprises a side box 28. The side box 28 is attached to a side wall of one of the longitudinal members 30, more precisely that of the side opposite the cabin 75. The box lateral 28 is placed between the front axle 3 and the rear axle 4.

The lateral box 28 receives the electric motor 10 and the reduction gear 9. In addition, the lateral box 28 can also accommodate other elements, such as for example a hydraulic pump (not shown) making it possible to activate a movement of the lifting arm 20 .

The side box 28 comprises several exterior faces, and a support surface 37 on which interior elements of the side box 28 are placed. The support surface 37 is surrounded by the spar 30 and by one or more exterior faces.

The side box 28 comprises at least one closable flap 21. In a closed position, the closable flap 21 can be locked, thus preventing any unauthorized access to the interior of the side box 28. In a closed position of the closable flap 21 , the electric motor 10 and the gearbox 9 are also protected against external shocks.

In an open position of the closable flap 21, access to the electric motor 10 and the reduction gear 9 is facilitated, thus making maintenance operations easier.

The reducer 9 is preferably placed near a rear face of the side box 28. The fixing element 11, bolted to the reducer 9, is fixed to the spar 30 by any appropriate means.

With reference to Figures 7 and 8, a passage space 29 is provided between the side box 28 and the spar 30. The transmission shaft 8 connects the reducer 9 located inside the side box 28 with the front axle 3 , through the passage space 29.

The passage space 29 consists of raising a lower limit of the spar 30 so that the lower limit of the spar 30 is higher than an upper limit of an interior face 38 of the side box 29.

The passage space 29 has a height at least equal to a diameter of the transmission shaft 8 and of a length such that the transmission shaft 8 passes diagonally through the passage space 29.

The side box 28 is raised relative to the front axle 3 and the rear axle 4, in accordance with the ground clearance provided by the first Cardan joint 7 and the second Cardan joint 17.

Other elements may be included within the side box 28. For example, the side box 28 may contain an air cooling block and electric variators. Liquid cooling circuits can be connected to the electric motor 10 in order to prevent it from overheating. Power cables at the output of the electric drives can power the electric motor 10.

With reference to Figures 5 to 8, the operation of the lifting machine 1 will be described.

A set of batteries (not shown) can be placed between the longitudinal beams 30. The set of batteries is made by combining together several battery elements, so as to achieve a sufficient terminal voltage to allow the operation of the lifting machine 1 , without the lifting machine 1 having to carry another motor such as an internal combustion engine. The battery cells can in principle be of any known type, for example lead-acid or lithium-ion type, and can be combined together and installed between the beams 30 in various ways.

The set of batteries supplies direct current to the block of electric variators (not shown). The power cables (not shown) at the output of the electric variator block supply the electric motor 10 with three-phase current.

The electric motor 10 is connected to the reducer 9, and the reducer 9 rotates the transmission shaft 8. The transmission shaft 8 rotates the transfer case 6, which directly drives the front axle 3, and which drives the rear axle 4 via the connecting shaft 5.

In particular, the first Cardan joint 7, disposed between the transmission shaft 8 and the transfer box 6, and the second Cardan joint 17, disposed between the transmission shaft 8 and the reduction gear 9, ensure a speed of homokinetic rotation of the output shaft of the reducer 9 and the input shaft of the transfer case 6, the first angle γ and the second angle δ being equal.

Although the invention has been described in connection with several particular embodiments, it is quite obvious that it is in no way limited and that it includes all the technical equivalents of the means described as well as their combinations if these fall within the scope of the invention.

The use of the verb “include”, “understand” or “include” and its conjugated forms does not exclude the presence of other elements or other steps than those set out in a claim.

In the claims, any parenthetical reference sign shall not be construed as a limitation of the claim.

Claims (20)

Work machine (1) comprising a first axle (3) and a second axle (4), a transfer box (6) secured to one of the first axle (3) and the second axle (4) and configured to drive the first axle (3) and the second axle (4), and at least one electric motor (10) for driving the transfer case (6), wherein said electric motor (10) drives the transfer case (6) by via a gearbox (9), the gearbox (9) having an output shaft and the transfer case (6) having an input shaft, the output shaft being coupled to the input shaft via a transmission shaft (8), an axis of rotation of the transmission shaft (8) and an axis of rotation of the input shaft being non-parallel and intersecting, and the shaft of transmission (8) and the input shaft being coupled by means of a first universal joint (7, 71). Work machine (1) according to claim 1, comprising two spars (30) parallel to each other and parallel to a central longitudinal axis (5) of the work machine (1). Work machine (1) according to the preceding claim, in which batteries used to power the electric motor (10) are arranged between the longitudinal members (30). Work machine according to one of the preceding claims, in which the reduction gear (9) and the transmission shaft (8) are connected by a second universal joint (17). Work machine according to one of the preceding claims, in which the first universal joint (7) and/or the second universal joint (17) is a Cardan joint. Work machine according to one of the preceding claims, in which the electric motor (10) is mounted on the reduction gear (9). Work machine according to one of the preceding claims, in which a rear end of the transmission shaft (8) is further away from the central longitudinal axis (5) than a front end of the transmission shaft. Work machine according to one of the preceding claims, in which the rear end of the transmission shaft (8) is placed in height, in a vertical direction of the work machine, relative to the first axle (3) . Work machine according to one of the preceding claims, in which a first angle between the input shaft of the transfer case (6) and the transmission shaft (8) is identical to a second angle between the shaft transmission (8) and the output shaft of the reducer (9). Work machine according to the preceding claim, in which an inclination of the output shaft of the reduction gear (9) relative to the central longitudinal axis (5) is greater than an inclination of the transmission shaft (8) relative to the central longitudinal axis (5). Work machine according to one of the preceding claims, in which the reduction gear (9) and the electric motor (10) are placed in a box (28), between the first axle (3) and the second axle (4) along a longitudinal direction of the work machine. Work machine according to claim 11, in which the box (28) comprises closable flaps (21). Work machine according to claim 11 or 12, in which the box (28) is raised, in the vertical direction of the work machine, relative to the first axle (3). Work machine according to one of claims 11 to 13, in which the reduction gear (9) is placed in a rear half of the box (28) in the longitudinal direction of the work machine. Work machine according to one of claims 11 to 14, which further comprises a hydraulic motor and a hydraulic pump used to actuate a lifting arm (20), the hydraulic motor and the hydraulic pump being preferably placed in the box ( 28). Work machine according to one of Claims 11 to 15 in combination with Claim 2, in which the box (28) is fixed to one of the two longitudinal members (30). Work machine according to the preceding claim, in which the reduction gear (9) is fixed to said spar (30) by means of a fixing element (11). Work machine according to claim 16 or 17, in which a passage space between an interior face of the box and said longitudinal member (30) communicates an interior of the box (28) and an underside of the chassis (2). Work machine according to claim 18, in which the transmission shaft (8) connects the reduction gear (9) and the first axle (3) through the passage space (29). Work machine according to the preceding claim, in which the transmission shaft (8) is positioned at least partially under the longitudinal members (30).