IT201800005615A1 - SELF-PROPELLED VEHICLE WITH FULL DRIVE - Google Patents

Description

DESCRIPTION

of the Italian Patent for Industrial Invention entitled:

"SELF-PROPELLED FULL-DRIVE VEHICLE"

TECHNICAL FIELD

The present invention relates to a self-propelled four-wheel drive vehicle, in particular an agricultural or earth-moving vehicle equipped with four-wheel drive.

PRE-EXISTING TECHNIQUE

Agricultural and / or earth-moving vehicles are known equipped with four-wheel drive, or equipped with a transmission unit that allows to transmit the driving force generated by an engine installed on board the vehicle with two pairs of wheels, of which at least one pair of wheels is of the steering type.

Said transmission assembly comprises a gearbox connected to the engine, a primary shaft connected to an output shaft of the gearbox and a secondary shaft also connected to the output shaft of the gearbox, in which the primary shaft is able to transmit the driving torque to a pair of non-steering wheels, for example rear wheels, and the secondary shaft is able to transmit the driving torque to the pair of steering wheels, for example front wheels.

Generally, one or more multiplier gears are interposed between the secondary shaft and the output shaft of the gearbox, configured to ensure that the speed of the pair of front steering wheels is greater, for example by 1.04 times, than at the speed of the pair of rear steering wheels. This is to avoid that the front steering wheels, turning at the same speed as the non-steering rear wheels, end up acting as a brake to the rear wheels, and because this higher speed of the steering wheels in four-wheel drive vehicles helps to reduce the turning radius.

In particular, the steering condition that allows to obtain the minimum possible turning radius is the so-called kinematic steering, in which the motion of a vehicle on a curved trajectory is determined by the pure rolling of the wheels, on a supporting ground, with respect to to a single instantaneous center of rotation O identified by the point of intersection of the rotation axes of all the wheels of the vehicle (see Figure 4).

For this condition to be met, the wheels must advance along a respective curved trajectory, having as its center the instantaneous center of rotation O, at a speed of advancement whose value in modulo is proportional to the distance from this instantaneous center of rotation and which are therefore greater for the inner wheels to the steering and larger for the outer wheels. Furthermore, the speeds V1FSW, V2FSW of the front FSW steering wheels must be on average higher than the speeds V1RW, V2RW of the rear non-steering RW wheels.

In practice, the wheels must rotate around their own axis at different rotation speeds from each other and it is necessary that the FSW steered front wheels rotate with respect to their axis of rotation at a speed that is on average higher than the average speed of the rear wheels. non-steered RW, as the steered front wheels are on average further away from the instantaneous center of rotation O.

A problem with the solution currently adopted is that the only speed increase value made available by the multiplier brings advantages only in certain conditions, for example in certain ranges of steering angles, or in the case of small obstacles to overcome.

This problem is exacerbated when an operator who is making a turn on this type of vehicle operates a right rear wheel brake or a left rear wheel brake to slow the proximal wheel to the instantaneous center of rotation in order to decrease the turning radius. as this further increases the speed at which the front wheels must rotate with respect to their own axis.

An object of the present invention is to solve the disadvantages of the current solutions in the context of a simple, rational and low cost solution. These purposes are achieved by the characteristics of the invention reported in the independent claim.

The dependent claims outline preferred and / or particularly advantageous aspects of the invention.

EXHIBITION OF THE INVENTION

The invention makes available a self-propelled four-wheel drive vehicle equipped with:

- a first steering axle to which a first pair of vehicle wheels is connected, which are kinematically connected to each other by means of a first differential,

- a second axle to which a second pair of vehicle wheels is connected, which are kinematically connected to each other by means of a second differential,

- an engine equipped with an output shaft, e

- a transmission unit connected to the engine output shaft and comprising:

o a gearbox connected to the motor output shaft,

o a primary shaft capable of transmitting motion from an output shaft of the gearbox to the second pair of wheels, e

o a secondary shaft capable of transmitting motion from the gearbox output shaft to the first differential and equipped with a first section connected to the output shaft and a second section connected to the first differential,

said transmission unit being characterized in that it comprises:

- a speed regulator device interposed between the first section and the second section of the secondary shaft and,

- an electronic control unit operatively connected to the regulator device,

in which the regulator device is configured to vary a value of the ratio between the angular velocity of the second section and the angular velocity of the first section at least as a function of an actuation signal sent by the electronic control unit. Thanks to this solution, the limitations of the prior art are overcome by means of a transmission unit that allows to exploit the advantages of distribution of the torque of the four-wheel drive in a wider spectrum of operating situations compared to known devices, such as for example the conditions of curves narrow and medium-large obstacles to overcome.

For example, an aspect of the invention provides that the transmission assembly may comprise a steering sensor configured to monitor the value of a parameter indicative of a steering angle of the first pair of wheels and that the electronic control unit is configured for operate the governor device according to the value of the parameter indicative of the steering angle monitored by the steering sensor.

In this way the vehicle allows to obtain an extremely small turning radius that approximates, or even reaches, the kinematic steering conditions, i.e. the minimum possible turning radius conditions, as the vehicle autonomously provides the right rotation speed. of the first pair of steering wheels.

Preferably, the electronic control unit can be configured to operate the regulator device when the indicative value of the monitored steering angle is greater than a value corresponding to a preset threshold steering angle.

Preferably, when the indicative value of the monitored steering angle is greater than a value corresponding to a steering angle of 40 °.

In this way the regulating device comes into operation when its speed regulation provides a substantial contribution to the steering, thus extending the useful life of the device itself.

According to another aspect of the invention, the electronic control unit can be configured to actuate the regulating device so as to vary the value of the ratio between the angular velocity of the second portion with respect to the angular velocity of the first portion between a minimum value of 1 and a maximum value of 1.4.

Thanks to this feature, an optimal compromise condition is reached between the need to reduce the turning radius, i.e. approaching the kinematic steering condition, and the need not to dig the soil and reduce mechanical stress on the vehicle.

Yet another aspect of the invention provides that the electronic control unit can be configured to actuate the regulating device so as to increase the value of the ratio between the speed of the second section with respect to the first section as the indicative value of the angle increases. of steering.

In this way, the gradual variation of the speed increase according to the increase of the steering angle allows to approach the kinematic steering condition, or to reach it, in a wide range of steering angles, while ensuring the controllability of the vehicle. .

A further aspect of the invention provides that the transmission unit may include a remote control device operatively connected to the electronic control unit and configured to control the actuation of the regulator device.

In this way the vehicle allows an operator to manually control the regulator device to adapt it to his specific needs, even momentary ones.

For example, the remote control device and the electronic control unit can be configured to operate the regulator device so as to set the value of the ratio between the speed of the second section with respect to the first section between a minimum value of 1 and a value maximum of 2.

Thanks to this solution, when an operator encounters a medium-large obstacle on his path, the vehicle allows him to easily overcome it, for example by allowing him to double the rotation speed of the first pair of steering wheels with respect to the second pair of wheels.

Another aspect of the invention provides that the remote control device and the electronic control unit can be configured to operate the regulator device in order to brake the second section.

In this way, the vehicle has another means available, in addition to the usual brakes connected to the wheels and the normal engine brake, to reduce the vehicle's stopping distances, which is added to the normal engine brake.

According to a further aspect of the invention, the vehicle may comprise: a first brake adapted to brake one wheel of the second pair of wheels, a second brake adapted to brake the other wheel of the second pair of wheels, and in which the transmission unit comprises a status sensor connected to the electronic control unit and configured to monitor an activated or deactivated state of the first brake and of the second brake, and in which the electronic control unit is configured to operate the regulator device so as to vary the ratio between the angular speed of the second section and the angular speed of the first section as a function of the value of the parameter indicative of the steering angle monitored by the steering sensor and as a function of the state of the first brake and of the second brake monitored by the status sensor, in such a way that said ratio is greater when the first brake or the second brake are in the activated state than when they are in the or been disabled.

In this way, when a vehicle operator acts on one of said brakes to reduce the steering angle, the transmission unit further automatically increases the rotation speed of the first pair of steering wheels to follow the kinematic steering conditions, thus reducing the turning radius of the vehicle.

Yet another aspect of the invention provides that the regulating device may comprise a differential mechanism which has: a casing integral in rotation with the first section of the secondary shaft, at least one satellite toothed wheel rotatably associated with the casing with respect to a central axis of the toothed wheel satellite itself, a first planetary toothed wheel adapted to mesh with the satellite toothed wheel, a first joint operated by the electronic control unit and adapted to selectively oppose the rotation of the first planetary toothed wheel, a second planetary toothed wheel adapted to mesh with the satellite toothed wheel and integral in rotation to the second section of the secondary shaft, and a second joint operated by the electronic control unit and configured to couple and uncouple in rotation the second section and the crankcase.

Thanks to this solution, the regulator device is particularly effective and at the same time compact, for installation in small spaces.

According to an aspect of the invention, the electronic control unit can be configured to operate the first joint as a function of the value of the parameter indicative of the steering angle monitored by the steering sensor, so as to increase the ratio between the angular speed of the second section and the angular velocity of the first section as the steering angle increases.

In this way the variation of the ratio between speed is obtained in a simple and effective way.

Furthermore, the second joint can comprise a clutch which can be actuated between a first operating position, in which it does not transmit rotation torques between the crankcase and the second portion, a second operating position, in which it rigidly connects the crankcase and the second portion to each other, and a plurality of intermediate positions in which it allows a partial transmission of torque between the crankcase and the second section, and the electronic control unit is also configured to actuate said clutch in at least one of the plurality of intermediate positions as a function of the value of the indicative parameter of the steering angle monitored by the steering sensor.

In this way the regular device is particularly fast in varying the ratio between the angular velocities.

The invention also makes available a speed regulator between two portions of a shaft comprising: a crankcase integral in rotation with the first portion of the shaft, at least one satellite toothed wheel rotatably associated with the crankcase with respect to a central axis of the satellite toothed wheel itself, a first planetary toothed wheel adapted to mesh with the satellite toothed wheel, a first joint adapted to selectively oppose the rotation of the first planetary toothed wheel, a second planetary toothed wheel adapted to mesh with the satellite toothed wheel and integral in rotation to the second section of the secondary shaft, and a second joint configured to couple and uncouple the second section and the crankcase in rotation.

BRIEF DESCRIPTION OF THE DRAWINGS

Further features and advantages of the invention will become evident from reading the following description provided by way of non-limiting example, with the aid of the figures illustrated in the attached tables.

Figure 1 is a diagram of a vehicle according to the invention.

Figure 2 is a diagram of a regulator device of a vehicle transmission assembly.

Figure 3 is a block diagram of the vehicle according to the invention.

Figure 4 is a diagram describing the kinematic steering conditions.

DETAILED DESCRIPTION

With reference to Figures 1, 2 and 3, the reference numeral 1 generally designates a self-propelled four-wheel drive vehicle, such as for example an agricultural vehicle or an earth-moving vehicle or an off-road vehicle.

The vehicle 1 comprises a supporting frame 5 defining a longitudinal axis X, for example substantially parallel to a normal direction of advance. A first steering axle 10 of the vehicle 1 is fixed to the supporting frame 5, for example positioned in a front portion of the vehicle 1, or positioned in a portion of the vehicle facing the normal forward direction of the vehicle.

The vehicle 1 comprises a first pair of steering wheels 15, or a pair of front steering wheels 15, which are articulated to the first axle 10 by means of suitable steering levers 20. Each wheel 15 of the first pair of wheels 15 is rotatably associated with a corresponding steering lever 20 according to respective rotation axes W1, W2 substantially lying on a plane parallel to a supporting ground of the vehicle itself.

The steering levers 20 are configured to vary the inclination of the rotation axes W1 and W2 of the wheels of the first pair of wheels 15 with respect to the longitudinal axis X of the vehicle.

The vehicle 1 comprises a steering sensor 25 configured to monitor the value of a parameter indicative of a steering angle of the first pair of wheels 15 with respect to a plane parallel to the longitudinal axis of the vehicle 1 and substantially perpendicular to a lying plane of a ground on which the first pair of wheels 15 rests.

Said steering sensor can for example be a sensor suitable for monitoring a change in the position of the steering levers 20 or for monitoring the rotation of a steering wheel or for monitoring the rotation of a power steering shaft or any possible element of the vehicle. fit for purpose.

The vehicle 1 comprises a second non-steering axle 30 fixed to the frame 5, for example in a rear region of the vehicle 1, to which a second pair of non-steering wheels 35 is connected, or a pair of rear non-steering wheels 35.

The wheels of the second pair of non-steering wheels 35 are rotatably associated with the second axle 30 with respect to rotation axes W3 and W4 substantially perpendicular to the longitudinal axis of the vehicle 1 and lying on a plane parallel to the ground on which the vehicle rests.

The vehicle 1 comprises a first brake 40, or a first rear brake 40, adapted to act on the angular speed of a wheel 35 of the second pair of wheels 35, and a second brake 45, or a second rear brake 45, adapted to act on the angular velocity of the other wheel 35 of the second pair of wheels 35. Said first brake 40 and second brake 45 are respectively controlled by means of a first braking control 50 and a second braking control 55.

Said first braking control 50 and second braking control 55 are physical controls, such as for example pedals or levers able to actuate an actuator of the respective brake.

The vehicle 1 is equipped with a status sensor 60 configured to monitor an activated or deactivated state of the first brake 40 and of the second brake 45, for example said sensor is configured to monitor the status of the first braking command 50 and of the second brake command. braking 55.

The vehicle 1 is equipped with an engine 65, for example endothermic, fixed to the supporting frame 5, and with a transmission unit 70, which is connected to an output shaft 75 of the engine 65 and is configured to transmit the angular velocity of said output shaft 75 to the first pair of wheels 15 and to the second pair of wheels 35.

The transmission unit 70 comprises a gearbox 80, integral with the supporting frame 5 and equipped with an input shaft 85 and an output shaft 90, in which the input shaft 85 is connected in rotation to the shaft d 'output 75 of engine 65.

The gearbox 80 is, for example, part of the supporting frame 5, that is, the gearbox 80 has a supporting function.

Preferably said input shaft 85 is integral, for example directly, in rotation with the output shaft 75, or the input shaft 85 rotates at the same angular speed as the output shaft of the motor 65.

It should be noted that in this discussion, when it is indicated that an element of the invention is "integral" to another element, it is understood that it is bound without degrees of freedom of movement with respect to the element to which it is integral.

The gearbox 80 can for example comprise at least one of a discontinuous gearbox, an automatic variator, or any other device suitable for the purpose.

The transmission unit 70 is equipped with a primary shaft 95 connected in rotation to the output shaft 90 of the gearbox 80 and adapted to transmit the rotary motion to the second pair of wheels 35. For example, the transmission unit 70 comprises a second differential 100 which kinematically connects the wheels 35 of the second pair of wheels 35 to each other, and the primary shaft 95 is able to transmit the rotary motion of the output shaft 90 to an input shaft of the second differential 100.

In practice, the primary shaft 95 has a first end directly connected in rotation to the output shaft 90 of the gearbox 80 and an opposite second end directly connected to the input shaft of the second differential 100.

It should be noted that in this discussion the term "differential" means an epicyclic mechanism equipped with two coaxial planetary gear wheels that mesh with at least one satellite gear wheel rotatably associated with a casing according to an axis substantially perpendicular to the axis of rotation of the planetary gear wheels.

However, it is not excluded that in other embodiments the differential may be any other device capable of dividing the input speed between two driving wheels based on the conditions of use, for example based on the resisting force acting on each individual wheel.

The second differential 100 comprises a first planetary toothed wheel integral in rotation with one wheel of the second pair of wheels 35, a second planetary toothed wheel integral in rotation with the other wheel of the second pair of wheels 35 and coaxial with the first planetary toothed wheel, and at least one satellite toothed wheel, which meshes with the first and second planetary toothed wheels and is rotatably associated with a casing, which is hinged to the second axle 30 with respect to a rotation axis coaxial to the planetary toothed wheels and is rotated with respect to said axis of rotation through the input shaft of the second differential itself.

The transmission assembly 70 comprises a secondary shaft 105 connected in rotation to the output shaft 90 of the gearbox 80 and adapted to transmit the rotary motion to the first pair of wheels 15. For example, the transmission assembly 70 comprises a first differential 110 which kinematically connects the wheels 15 of the first pair of wheels 15 to each other, and the secondary shaft 105 is able to transmit the rotary motion of the output shaft 90 to an input shaft of the first differential 110.

The first differential 110 comprises a first planetary toothed wheel integral in rotation with one wheel of the first pair of wheels 15, a second planetary toothed wheel integral in rotation with the other wheel of the first pair of wheels 15 and coaxial with the first planetary toothed wheel, and at least one satellite toothed wheel, which meshes with the first and second planetary toothed wheels and is rotatably associated with a casing, which is hinged to the first axle 10 with respect to an axis of rotation coaxial with the planetary toothed wheels and is rotated with respect to the hinge axis through the input shaft of the first differential itself.

The secondary shaft 105 receives the rotary motion from the output shaft 90 of the speed change 80 by means of the interposition of a fixed speed variator 115, for example configured to increase the rotation speed of the secondary shaft 105 with respect to the speed output shaft rotation 90.

As mentioned above, the variable speed drive 115 is fixed, that is, the variable speed drive 115 has a single pre-settable speed difference between the output shaft 90 and the secondary shaft 105. Preferably, the fixed variable speed drive 115 is configured to increase the rotation speed of the secondary shaft 105 with respect to the rotation speed of the output shaft 90 by approximately 1.02 ÷ 1.04 times.

In the illustrated embodiment, the fixed speed variator 115 comprises a gear, for example provided with an initial toothed wheel 120 integral in rotation with the output shaft 90 and a final toothed wheel 125 integral in rotation with the secondary shaft 105 For example, the initial toothed wheel 120 is keyed to the output shaft and the final toothed wheel 125 is keyed to the secondary shaft 105. The secondary shaft 105 is equipped with a first section 130 connected to the output shaft. 90, ie the first section 130 is connected to the output shaft 90 of the speed change 80 by means of the fixed speed variator 115. For example, the final toothed wheel 125 of the gear of the speed variator 115 is keyed on this first section 130.

The secondary shaft 105 is also equipped with a second section 135 connected to the second differential 100. In the illustrated embodiment, an end of the second section 135 opposite the first section 130 rotates at the same rotation speed of the input shaft of the first differential.

The transmission unit 70 comprises a speed regulating device 140 interposed between the first section 130 and the second section 135 of the secondary shaft 105 and configured to vary a value of the ratio between the angular velocity of the second section 135 and the angular velocity of the first stretch 130.

In practice, the regulator device 140 is configured to vary the value of the ratio between the angular velocity of the input shaft of the first differential 110 and the angular velocity of the input shaft of the second differential 100.

It should be noted that in this discussion, the "value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130" means the numerical value obtained by dividing the angular velocity of the second portion 135 by the angular velocity of the first portion 130.

The regulating device 140 comprises a differential mechanism 145 configured to allow to vary the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 to any value between a minimum value of 1 and a maximum value of 2.

The differential mechanism is equipped with a casing 150 integral in rotation to the first section 130 of the secondary shaft 105. For example, the casing 150 is keyed to the first section 130 of the secondary shaft 105.

The differential mechanism 145 comprises a conical satellite toothed wheel 155, which is rotatably associated with the casing 150 with respect to a central axis of the satellite toothed wheel itself.

The satellite toothed wheel 155 is housed inside the casing 150 and its axis of rotation with respect to the casing 150 is perpendicular to an axis of rotation of the casing itself. Furthermore, the axis of rotation of the satellite toothed wheel 155 is perpendicular to a rotation axis of the first section 130 of the secondary shaft 105.

The differential mechanism 145 is also equipped with a first conical planetary toothed wheel 160, adapted to mesh with the satellite toothed wheel 155.

The first planetary toothed wheel 160 is arranged with a central axis coaxial to the first section 130 of the secondary shaft 105, and, for example, is contained, preferably entirely, inside the casing 150.

The differential mechanism 145 comprises a second conical planetary toothed wheel 165, which is coaxial to the first planetary toothed wheel 160 and meshes with the satellite toothed wheel 155. In particular, the second planetary toothed wheel 165 meshes with the satellite toothed wheel 155 from a end of the satellite toothed wheel 155 diametrically opposite with respect to the first planetary toothed wheel 160.

The second planetary gear wheel 165 is also contained, for example entirely, inside the casing 150.

The second planetary toothed wheel 165 is integral in rotation to the second section 135 of the secondary shaft 105, for example the second planetary toothed wheel is keyed to the second section 135 of the secondary shaft 105.

In the illustrated embodiment, the differential mechanism 145 also comprises a further satellite toothed wheel 170 coaxial to the satellite toothed wheel 155, also rotatably associated with the casing 150 and which meshes with the first planetary toothed wheel 160 and with the second planetary toothed wheel 165. The differential mechanism 145 also comprises a first joint provided with a portion integral with the bearing frame 5 and configured to selectively free or oppose the rotation of the first planetary toothed wheel 160 with respect to the central axis of the first planetary toothed wheel itself.

In particular, the first joint can be operated between a first operating position, in which it leaves the first planetary gear 160 free to rotate with respect to its axis, a second operating position, in which it blocks the rotation of the first planetary gear 160 with respect to its axis. axis, and a plurality of intermediate modulation positions, in which it contrasts, or reduces, the angular velocity of the first planetary toothed wheel 160.

Specifically, in the second operative position the first joint makes the first planetary toothed wheel 160 integral with the supporting frame 5 of the vehicle 1 and in the intermediate positions it brakes the rotation of the first planetary toothed wheel 160.

In the embodiment illustrated in the drawings, the first coupling comprises a clutch 175 provided with a shaft 180 integral in rotation to the first planetary gear 160.

The clutch 175 is coaxial to the first planetary toothed wheel 160, for example it is entirely contained within the crankcase 150.

Preferably, the clutch 175 of the first joint also comprises a casing 185 integral with the bearing frame 5, at least one friction disc 190 integral with the casing 185, at least one friction disc 195 integral with the shaft 180 and a coupling device (not shown ) configured to selectively move away and approach in contact said friction discs 190,195.

It is not excluded that in an alternative embodiment the first joint may comprise a brake equipped with a jaw capable of clamping a disc keyed on the shaft integral in rotation to the first planetary gear 160.

The differential mechanism 145 comprises an angular sensor 200 configured to monitor the value of a parameter indicative of the angular velocity of the first planetary gear 160, for example configured to monitor the value of a parameter indicative of the angular velocity of the shaft 180 of the clutch 175 of the first joint.

The differential mechanism 145 also includes a second joint configured to selectively couple and uncouple in rotation the crankcase 150 and the second section 135 of the secondary shaft 105.

In particular, the second joint can be operated between a first operating position, in which it leaves the casing 150 and the second section 135 free to rotate relative to each other, a second operating position, in which to make the casing 150 and the second section 135 integral in rotation, and a plurality of intermediate modulation positions in which it contrasts, or reduces, the difference in angular speed between the casing 150 and the second section 135.

Since the second planetary toothed wheel 165 is integral in rotation to the second portion 135, the second joint also acts on the angular speed of the second planetary toothed wheel 165.

When the first joint is operated in the first operating position and the second joint is operated in the first operating position, the transmission of motion from the gearbox output shaft to the first pair of wheels 15 is interrupted.

That is, in this operating configuration the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 is equal to 0.

When the first joint is operated in the first operating position and the second joint is operated in the second operating position, the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 is equal to 1.

When the first joint is operated in the second operating position and the second joint is operated in the first operating position, the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 is equal to 2.

In the embodiment shown in the figures, the second joint comprises a clutch 205 provided with a casing 210 integral in rotation with the crankcase 150.

This clutch 205 is coaxial with the second planetary toothed wheel 165, and, for example, is external to the crankcase 150.

The clutch 205 of the second joint also comprises at least one friction disc 215 integral with the casing 210, at least one friction disc 220 integral with the second portion 135 and a coupling device (not shown) configured to selectively move away and approach said discs in contact of friction 210,220.

It is not excluded that in an alternative embodiment the second joint may include a brake equipped with a jaw integral with the casing 150 and capable of clamping a disc keyed on the second section 135 in a vice.

The transmission assembly 70 comprises an electronic control unit 225 operatively connected to the regulator device 140 and configured to send an actuation signal to the regulator device 140 to set the value of the ratio between the angular velocity of the second section 135 and the angular velocity of the first section 130.

In the illustrated embodiment, the electronic control unit 225 is configured to operate, for example by means of appropriate drive systems (not shown), the first joint and the second joint. That is, the electronic control unit 225 is configured to operate, for example by means of appropriate drive systems (not shown), the clutch 175 of the first joint and the clutch 205 of the second joint. This is to modulate the angular velocity of the first planetary toothed wheel 160 and of the second planetary toothed wheel 165, so as to set, through the conformation of the differential mechanism 145, the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first section 130. The electronic control unit 225 is operatively connected to the angular sensor 200 and is configured to actuate the clutch 175 of the first joint, for example also the clutch 205 of the second joint, between the first operating position and the second operating position (including extremes) until the angular velocity of the first planetary gear monitored by the angle sensor 200 reaches a preset value.

For example, the electronic control unit 225 can be configured to actuate the regulating device 140 so that the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 is equal to 1. That is, in such configuration realizes the normal forward travel of the vehicle with all-wheel drive activated.

In this case, the electronic control unit 225 is configured to operate the first joint in the first operating position and to operate the second joint in the second operating position.

The electronic control unit 225 can also be configured to deactivate the four-wheel drive of the vehicle, i.e. the electronic control unit 225 is configured to actuate the regulating device 140 so as to interrupt the transmission of torque between the first section 130 and the second section 135.

In this case, the electronic control unit 225 is configured to operate the first joint in the first operating position and to operate the second joint in the first operating position.

The electronic control unit 225 is operatively connected to a remote control device 230 of the regulator device 140, which is configured to set, through the electronic control unit 225, the value of the ratio between the angular velocity of the second section 135 and the angular velocity of the first section 130, for example to a required value between a minimum value of 1 and a maximum value of 2.

In addition, the remote control device 230 and the electronic control unit 225 can be configured to control the actuation of the regulator device 140 in such a way as to brake the wheels of the vehicle 1, for example to brake the first pair of wheels 15 vehicle 1. That is, the remote control device 230 can be configured to control the actuation of the regulator device 140, by means of the electronic control unit 225, in such a way as to reduce the angular velocity of the second section 135.

In this braking configuration, in the illustrated embodiment, the remote control device 230 and the electronic control unit 225 are configured to actuate the first joint in an intermediate position between the first operating position and the second operating position and to actuate the second joint in the second operative position so as to reduce the angular velocity of the second section 135

That is, the remote control device 230 and the electronic control unit 225 are configured to operate the first joint in an intermediate position between the first operating position and the second operating position and to operate the second joint in the second operating position so as to reduce the speed of the countershaft, for example to brake the countershaft.

Optionally, the remote control device 230 and the electronic control unit 225 can be configured to actuate the first joint from the first operating position to the second operating position and to actuate the second joint in the second operating position so as to reduce the angular velocity. of the second section 135, or of the secondary shaft.

Said intermediate position between the first operative position and the second operative position in which the first joint is actuated (to realize the braking configuration) is directly proportional to the value requested by the remote control device 230.

In particular, the electronic control unit 225 is configured to actuate the clutch 175 of the first joint in an intermediate position between the first operating position and the second operating position and to actuate the second joint in the second position, so that the speed value angle of the first planetary gear 160 detected by the angular sensor 200 is equal to a predetermined value corresponding to the value required by the remote control device 230. Furthermore, the electronic control unit 225 can be configured to automatically operate the regulator device 140 in a such as to reduce the angular speed of the secondary shaft when the status sensor 60 detects that both the first brake 40 and the second brake 45 are in the activated state.

That is, in the embodiment described, the electronic control unit 225 is configured to automatically operate the first joint in an intermediate position between the first position and the second position and to operate the second joint in the second position so as to reduce the speed angular of the secondary shaft, when the status sensor 60 detects that both the first brake 40 and the second brake 45 are in the activated state.

The remote control device 230 and the electronic control unit 225 can also be configured to control the actuation of the regulator device 140 in such a way as to accelerate the first pair of wheels 15 of the vehicle 1. That is, the remote control device 230 and the electronic control unit 225 can be configured to control the actuation of the regulator device 140 in such a way as to set the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 to a value, requested by the remote control device 230, between a minimum value of 1 and a maximum value of 2.

Preferably, this value is comprised between a minimum value of 1.6 and a maximum value 2.

For example, the value can be preset and be approximately 1.8.

In the illustrated embodiment, the electronic control unit 225 and the remote control device 230 are configured to operate the first joint in the second operating position and to operate the second joint in the first operating position or in an intermediate position between the first position operating position and the second operating position in such a way as to set the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 to a value, requested by the remote control device 230, between a minimum value of 1 and a maximum value of 2.

In particular, the electronic control unit 225 and the remote control device 230 can be configured to operate the first joint in the second operating position and to operate the second joint in the first operating operation position in such a way as to set the value equal to 2. of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130.

The electronic control unit 225 is also operationally connected to the steering sensor 25 and is configured to operate the regulator device 140 according to the parameter indicative of the steering angle monitored by the steering sensor 25.

For example, the electronic control unit 225 is configured to automatically operate the regulator device 140 so as to set equal to 1 the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 when the indicative value of the steering angle monitored by the steering sensor is between 0 ° and a preset threshold value.

That is, in the illustrated embodiment, the electronic control unit 225 is configured to automatically operate the first joint in the first operating position and the second joint in the second operating position when the indicative value of the steering angle monitored by the steering sensor 25 it is between 0 ° and the preset threshold value.

Furthermore, the electronic control unit 225 is configured to automatically operate the regulator device 140 so as to vary with respect to the value of 1, the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130, when the indicative value of the steering angle monitored by the steering sensor 25 is greater than a value corresponding to the preset threshold value of the steering angle.

In particular, when the indicative value of the steering angle monitored by the steering sensor 25 is greater than a value corresponding to the preset value of the threshold steering angle, the electronic control unit 225 is configured to automatically operate the governor device 140 so as to vary, for example by setting, the value of the ratio between the angular speed of the second section 135 and the speed of the first section 130 between a minimum value of 1 and a maximum value of 2, for example between a minimum value of 1, 2 and a maximum value of 1.4, depending on the parameter indicative of the steering angle monitored by the steering sensor 25.

For example, said preset threshold value of the steering angle is between 30 ° and 40 °, preferably it is equal to 40 °.

Preferably, the electronic control unit 225 is configured to automatically operate the regulating device 140 so as to increase the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130, for example proportionally, as the the indicative value of the steering angle monitored by the steering sensor 25.

In the embodiment shown in the figures, the electronic control unit 225 is configured to actuate the first joint in an intermediate position between the first operating position and the second operating position so as to vary, for example set, the value of the ratio between the angular velocity of the second portion 135 and the velocity of the first portion between a minimum value of 1 and a maximum value of 2, for example between a minimum value of 1.2 and a maximum value of 1.4, when the indicative value of the steering angle monitored by the steering sensor 25 is greater than a value corresponding to the preset threshold value of the steering angle and in which this ratio value is a function of the indicative parameter of the steering angle monitored by the steering sensor 25.

For example, the electronic control unit 225 is configured to automatically operate the first joint from a first intermediate position to a second intermediate position, placed between the first operating position and the second operating position, of which the first intermediate position is closer. to the first operating position with respect to the second intermediate position, as the steering angle measured by the steering sensor 25 increases, when the indicative value of the steering angle monitored by the steering sensor 25 is greater than a value corresponds to the preset value of steering angle threshold.

Preferably, the electronic control unit 225 can be configured to operate the second joint in an intermediate position between the first operating position and the second operating position when the indicative value of the steering angle monitored by the steering sensor 25 is greater than a value corresponding to the preset steering angle threshold value.

In this way, the regulator device is particularly quick in passing from one operating configuration to the other, in particular in passing from the operating condition with steered wheels to the operating condition with straight wheels. Furthermore, this condition allows to increase the useful life of the clutches of the two joints, since the modulation of the friction of the second joint allows to decrease the relative speeds on both clutches which consequently will have more limited wear compared to the condition in which there is sliding on only one of the two clutches, ie that of the first joint.

Furthermore, the electronic control unit 225 is also operatively connected to the status sensor 60 and is configured to actuate the regulator device 140 so as to vary, for example set, the value of the ratio between the angular velocity of the second section 135 and the angular velocity of the first section 130 between a minimum value of 1 and a maximum value of 2, for example between a minimum value of 1.2 and a maximum value of 1.6, when the status sensor 60 detects that only one of the first brake 40 and second brake 45 are in the activated state and when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value.

In particular, when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value, the electronic control unit 225 is configured to operate the regulator device 140 so as to vary, for example set the value of the ratio between the angular velocity of the second portion 135 and the angular velocity of the first portion 130 so that said ratio value is greater when the status sensor 60 detects that only one of the first brake 40 and the second brake 45 is in the activated state with respect to when the status sensor detects that both the first brake 40 and the second brake 45 are in the deactivated state.

In the embodiment shown in the drawings, when the status sensor 60 detects that only one of the first brake 40 and the second brake 45 is in the activated state and when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value, the electronic control unit 225 is configured to operate the first joint in an intermediate position between the first operating position and the second operating position closest to the second operating position with respect to the intermediate position in which the The electronic control unit 225 is configured to operate the first joint when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value and the status sensor 60 detects that it is the first brake 40 that the second brake 45 are in the deactivated state.

That is, when the status sensor 60 detects that only one of the first brake 40 and the second brake 45 is in the activated state and when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset value threshold, the electronic control unit 225 is configured to actuate the clutch 175 of the first joint so that the angular velocity of the first planetary gear 160 is less than the angular velocity of the first planetary gear 160 required by the electronic unit of control 225 when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value and the status sensor 60 detects that both the first brake 40 and the second brake 45 are in the deactivated state.

Furthermore, when the status sensor 60 detects that only one of the first brake 40 and the second brake 45 is in the activated state and when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset value threshold, the electronic control unit 225 is configured to actuate the second joint in an intermediate position between the first operating position and the second operating position closest to the first operating position with respect to the intermediate position in which the electronic control unit 225 is configured to operate the second joint when the value of the parameter indicative of the steering angle monitored by the steering sensor 25 is greater than the preset threshold value and the status sensor 60 detects that both the first brake 40 and the second brake 45 are found in the deactivated state.

Furthermore, in each different configuration of the electronic control unit 225, the electronic control unit 225 can be configured to control in feedback by means of the angular sensor 200 that the angular velocity of the first planetary gear 160 is equal to a preset value of angular velocity corresponding to the value required by the electronic control unit 225 of the ratio between the angular velocity of the first portion 130 and the angular velocity of the second portion 135 or towards.

For example, the electronic control unit 225 is configured to monitor through the angular sensor 220 the angular velocity of the first planetary wheel 160 and to actuate the clutch 175 of the first joint towards the first operating position or towards the second operating position when the value angular velocity measured by the angular sensor 220 is respectively greater or less than a preset angular velocity value corresponding to the value required by the electronic control unit 225 of the ratio between the angular velocity of the first portion 130 and the angular velocity of the second portion 135.

Some operating configurations of the vehicle according to the invention are described below.

An operating configuration is that in which an operator of the vehicle 1 wishes to activate the four-wheel drive. In this case, the operator can act on the remote control device 230 to operate the regulator device 140 so that the first joint is in the first operating position and the second joint is in the second operating position, so that the first pair of wheels 15 the angular speed of the output shaft 90 of the gearbox 80 is transmitted, for example increased by the ratio applied by the fixed speed variator 115. The vehicle 1 also allows disabling the four-wheel drive. For example, in this case the operator can act on the remote control device 230 to operate the regulator device so that both the first joint and the second joint are in the first operating position, so as to interrupt the transmission of the drive torque to the first torque. of wheels 15.

Another operating configuration that can be set manually by the operator through the remote control device 230 allows the first pair of wheels 15 to be accelerated with respect to the second pair of wheels 35 so as to overcome with the first pair of wheels 15 obstacles present on the ground in the direction of advancement of the vehicle 1. In particular, the worker can operate the regulating device 140 by means of the remote control device 230 to bring the first joint into the second operating position and the second joint into the first operating position, so that a value of the ratio between the angular speed of the second section 135 and the angular speed of the first section 130 substantially equal to 2. That is, the first pair of wheels 15 rotates at an angular speed equal to double multiplied by the ratio of the fixed speed variator 115 with respect to the second pair of wheels 35.

Still another operating configuration of the electronic control unit 225 allows to realize an auxiliary braking of the vehicle wheels. For example, when the operator acts simultaneously on the first braking command 50 and on the second braking command 55, the electronic control unit 225 activates the regulating device 140 bringing the second joint into the second operating position and the first joint into a position intermediate between the first operating position and the second operating position, reducing the angular speed of the first wheels 15 with respect to the second pair of wheels 35.

A further operating configuration of the electronic control unit 225 allows the first pair of wheels 15 to be accelerated with respect to the second pair of wheels 35 to reduce the steering angle during steering. In particular, when the electronic control unit 225 detects by means of the steering sensor 25 that the steering angle of the first pair of wheels 15 is greater than a predetermined threshold value, it activates the regulating device 140 so as to bring the first joint from the first position to an intermediate position between the first operating position and the second operating position.

When the value of the steering angle monitored by the steering sensor 25 falls below the threshold value, the electronic control unit 225 operates the regulator device 140 to return the first joint to the first operating position.

The invention thus conceived is susceptible of numerous modifications and variations, all of which are within the scope of the inventive concept.

Furthermore, all the details can be replaced by other technically equivalent elements. In practice, the materials used, as well as the contingent shapes and dimensions, may be any according to requirements without thereby departing from the scope of the protection of the following claims.

Claims (13)

CLAIMS 1. Self-propelled all-wheel drive vehicle (1) equipped with: - a first steering axle (10) to which a first pair of wheels (15) of the vehicle (1) is connected, which are kinematically connected to each other by means of a first differential (110), - a second axle (30) to which a second pair of wheels (35) of the vehicle (1) is connected, which are kinematically connected to each other by means of a second differential (100), - a motor (65) equipped with an output shaft (75), and - a transmission unit (70) connected to the output shaft (75) of the engine (65) and comprising: o a gearbox (80) connected to the output shaft (75) of the motor (65), o a primary shaft (95) capable of transmitting motion from an output shaft (90) of the gearbox (80) to the second pair of wheels (35), and or a secondary shaft (105) adapted to transmit the motion from the output shaft (90) of the gearbox (80) to the first differential (110) and equipped with a first section (130) connected to the output shaft ( 90) and a second section connected to the first differential (110), said transmission unit (70) being characterized in that it comprises: - a speed regulator device (140) interposed between the first section (130) and the second section (135) of the secondary shaft (105) and, - an electronic control unit (225) operatively connected to the regulator device (140), in which the regulating device (140) is configured to vary a value of the ratio between the angular velocity of the second portion (135) and the angular velocity of the first portion (130) at least as a function of an actuation signal sent by the electronic unit of control (225). Vehicle (1) according to claim 1, comprising a steering sensor (25) configured to monitor the value of a parameter indicative of a steering angle of the first pair of wheels (15) and in which the electronic control unit (225) is configured to operate the governor device (140) according to the value of the parameter indicative of the steering angle monitored by the steering sensor (25). Vehicle (1) according to claim 2, wherein the electronic control unit (225) is configured to operate the regulating device (140) when the indicative value of the monitored steering angle is greater than a value corresponding to a preset threshold steering angle. Vehicle (1) according to claim 3, wherein the electronic control unit (225) is configured to actuate the regulating device (140) so as to set the value of the ratio between the speed of the second stretch (135) with respect to in the first section (130) to a preset value between a minimum value of 1 and a maximum value of 1.4. Vehicle (1) according to claim 2, wherein the electronic control unit (225) is configured to actuate the regulating device (140) so as to increase the value of the ratio between the angular velocity of the second section (135) with respect to the angular velocity of the first section (130) as the indicative value of the steering angle increases. 6. Vehicle (1) according to claim 1, wherein the transmission unit (70) comprises a remote control device (230) operatively connected to the electronic control unit (225) and configured to control the actuation of the regulator device. Vehicle (1) according to claim 6, wherein the remote control device (230) and the electronic control unit (225) are configured to operate the regulator device (140) so as to set the value of the ratio between the speed of the second section (135) with respect to the first section (130) to a required value between a minimum value of 1 and a maximum value of 2. Vehicle (1) according to claim 6, wherein the remote control device (230) and the electronic control unit (225) are configured to actuate the regulator device (140) so as to brake the second section (135 ). Vehicle (1) according to claim 2, comprising: - a first brake (40) adapted to brake a wheel of the second pair of wheels (35), - a second brake (45) designed to brake the other wheel of the second pair of wheels (35), and in which the transmission unit includes a status sensor (60) connected to the electronic control unit (225) and configured to monitor an activated or deactivated state of the first brake (40) and of the second brake (45), and in which the electronic control unit (225) is configured to actuate the regulating device (140) so as to set the ratio between the angular velocity of the second portion (135) and the angular velocity of the first portion (130) in operation the value of the parameter indicative of the steering angle monitored by the steering sensor (25) and as a function of the state of the first brake (40) and of the second brake (45) monitored by the status sensor (60), so that said ratio is greater when the first brake (40) or the second brake (45) are in the activated state than when they are in the deactivated state. Vehicle (1) according to claim 1, wherein the regulating device comprises a differential mechanism (145) which has: - a casing (150) integral in rotation to the first section (130) of the secondary shaft (105), - at least one satellite toothed wheel (155) rotatably associated with the casing (150) with respect to a central axis of the satellite toothed wheel itself, - a first planetary toothed wheel (160) adapted to mesh with the satellite toothed wheel (155), - a first joint (175) operated by the electronic control unit (225) and adapted to selectively contrast the rotation of the first planetary gear wheel (160), - a second planetary toothed wheel (165) adapted to mesh with the satellite toothed wheel (155) and integral in rotation to the second section of the secondary shaft (105), and - a second joint (205) operated by the electronic control unit (225) and configured to couple and uncouple in rotation the second section (135) and the casing (150). Vehicle (1) according to claims 2 and 10, in which the electronic control unit (225) is configured to actuate the first joint (175) as a function of the value of the parameter indicative of the steering angle monitored by the steering (25), so as to set the value of the ratio between the angular velocity of the second portion (135) and the angular velocity of the first portion (130). Vehicle (1) according to claim 11, wherein the second joint comprises a clutch (205) operable between a first operating position, in which it does not transmit rotation torques between the casing (150) and the second portion (135), a second operating position, in which it rigidly connects the casing (150) and the second section (135) to each other, and a plurality of intermediate modulation positions in which it allows a partial transmission of torque between the casing (150) and the second section (135), and in which the electronic control unit is also configured to actuate said clutch (205) in at least one of the plurality of intermediate positions as a function of the value of the parameter indicative of the steering angle monitored by the steering sensor. 13. A speed regulating device (140) between a first portion (130) and a second portion (135) of a shaft (105) comprising: - a casing (150) integral in rotation with the first section (130) of the shaft (105), - at least one satellite toothed wheel (155) rotatably associated with the casing (150) with respect to a central axis of the satellite toothed wheel itself, - a first planetary toothed wheel (160) adapted to mesh with the satellite toothed wheel (155), - a first joint (175) adapted to selectively oppose the rotation of the first planetary toothed wheel (160), - a second planetary toothed wheel (165) adapted to mesh with the satellite toothed wheel (155) and integral in rotation to the second section (135) of the secondary shaft (105), and - a second joint (205) configured to couple and uncouple in rotation the second section (135) and the casing (150).