GB2211475A - Device for controlling the four-wheel drive and the differentials of a tractor - Google Patents
Device for controlling the four-wheel drive and the differentials of a tractor Download PDFInfo
- Publication number
- GB2211475A GB2211475A GB8824942A GB8824942A GB2211475A GB 2211475 A GB2211475 A GB 2211475A GB 8824942 A GB8824942 A GB 8824942A GB 8824942 A GB8824942 A GB 8824942A GB 2211475 A GB2211475 A GB 2211475A
- Authority
- GB
- United Kingdom
- Prior art keywords
- tractor
- differentials
- devices
- unlocking
- locking
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000001133 acceleration Effects 0.000 description 1
- 230000002547 anomalous effect Effects 0.000 description 1
Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K23/00—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for
- B60K23/04—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for for differential gearing
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60K—ARRANGEMENT OR MOUNTING OF PROPULSION UNITS OR OF TRANSMISSIONS IN VEHICLES; ARRANGEMENT OR MOUNTING OF PLURAL DIVERSE PRIME-MOVERS IN VEHICLES; AUXILIARY DRIVES FOR VEHICLES; INSTRUMENTATION OR DASHBOARDS FOR VEHICLES; ARRANGEMENTS IN CONNECTION WITH COOLING, AIR INTAKE, GAS EXHAUST OR FUEL SUPPLY OF PROPULSION UNITS IN VEHICLES
- B60K23/00—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for
- B60K23/08—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for for changing number of driven wheels, for switching from driving one axle to driving two or more axles
- B60K23/0808—Arrangement or mounting of control devices for vehicle transmissions, or parts thereof, not otherwise provided for for changing number of driven wheels, for switching from driving one axle to driving two or more axles for varying torque distribution between driven axles, e.g. by transfer clutch
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Arrangement And Driving Of Transmission Devices (AREA)
- Arrangement And Mounting Of Devices That Control Transmission Of Motive Force (AREA)
Abstract
A device for controlling the four-wheel drive (8) and the differentials (4, 5) of a tractor (1) comprises an electronic control unit (9) supplied by means (10,11,12) for sensing the operating conditions of the tractor and arranged to pilot the electroactuators of the devices for engaging and disengaging four-wheel drive (8) and for locking and unlocking the differentials (4, 5). The electronic unit (9) can be set by means of selectors (13,14,15) in three different operating modes, in two of which it carries out manually the functions of engagement and disengagement of four-wheel drive (8) and locking and unlocking of the two differentials (4, 5), and in the third of which it carries out these functions automatically in response to signals from the sensor means (10,11, 12). <IMAGE>
Description
DEVICE FOR CONTROLLING THE FOUR-WHEEL DRIVE
AND THE DIFFERENTIALS OF A TRACTOR
The present invention relates generally to tractors provided with devices for engagement and disengagement of four-wheel drive and locking and unlocking of the front and rear differentials. These devices are nrmally driven by means of electroactuators, usually solenoid valves, operated manually by the tractor operator. The selection of engagement or disengagement of four-wheel drive and locking and unlocking of the differentials is generally bound by the principle of always ensuring maximum traction whilst working in the 5eld and of facilitating manoeuvring and transporting operations.
Since, as stated, this selection can conventionally be carried out only at the wish of the operator, t obviously depends on his skill and may not always be the optimum in relation to the operating conditions of the tractor.
The object of the present invention is to avoid the above problem and to produce a control device operatively associated with the electroactuators of the f"r-wheel drive and the dIfferentIals of the tractor, which retains the possibility of manual control but is able to cause engagement and disengagement of four-wheel drive and locking and unlocking of the differentials of the tractor automatically and in an optimal manner.
According to an aspect of the present invention there is provided a tractor with devices for engagement and disengagement of four-wheel drive and locking and unlocking of the front and rear differentials by means of respective electroactuators, characterised in that a control device is provided which is operatively associated with the electroactuators of the devices for engagement and disengagement of four-wheel drive and for locking and unlocking of the differentials, comprising means for sensing the operating conditions of the tractor and an electronic control unit supplied with signals from the sensor means and arranged to pilot the electroactuators; the electronic control unit being settable by means of selectors in three different operating modes, in two of which it carries out manually the operations of engagement and disengagement of four-wheel drive and locking and unlocking of the differentials respectively, and in the third of which it carries out these functions automatically in response to the signals from the sensor means.
According to a further aspect of the present invention there is provided a method for automatically controlling the devices for locking and unlocking of the front and rear differentials and/or the devices for engagement and disengagement of four-wheel drive in an agricultural tractor, characterised in that it consists of::
- setting the locking and unlocking devices and/or the engagement and disengagement devices in the condition corresponding respectively to locking of the differentials and to engagement of four-wheel drive,
- detecting the forward speed, the steering angle and the condition of asymmetric braking of the tractor, and obtaining indicative electrical signals,
- using the electrical signals automatically and reversibly to switch the locking and unlocking devices and/or the engagement and disengagement devices into the condition corresponding respectively to unlocking of the differentials and to disengagement of four-wheel drive, if the speed of the tractor is greater than a predetermined threshold value, and/o'r if the steering angle exceeds a predetermined threshold value, and/or even in the case of asymmetric braking.
These sensors means include, to advantage, detectors of the steering angle, asymmetric braking conditions, and the speed at which the tractor is moving.
By means of these sensors, the electronic control unit is able to detect the operating conditions of the tractor and consequently to pilot the electroactuators of the devices for engagement and disengagement of four-wheel drive and locking and unlocking of the differentials. Thus, for example, if the speed at which the tractor is moving exceeds a predetermined threshold value, the electronic unit causes disengagement of four-wheel drive. If te front wheels are turned beyond a certain angle or during unilateral braking, the control unit automatically unlocks the differentials.
In practice, the operating logic of the electronic unit can enable the operation of the tractor to be optimised in exact dependence on the various operative situations, independently of the wishes of the driver.
Furthermore, the device according to the present invention still ensures the possibility of manual control, should this be necessary in particular circumstances.
An embodiment of the invention is described below, by way of example only, with reference to the accompanying drawing, in which:
FIGURE 1 shows a tractor in diagrammatic form with a schematic representation of an electronic control device.
With reference to the drawing, an agricultural tractor is generally and schematically indicated 1 and is provided with front wheels 2 and rear wheels 3 associated respectively with a front differential and a rear differential, schematically indicated 4, 5.
The front wheels 2 are steered in known manner by a steering wheel 6, and a braking circuit, not illustrated, operated by means of a pedal device 7, is provided for symmetric or asymmetric braking of the wheels 2 and 3.
The rear wheels 3 are permanently driven, while the front wheels 2 may be rendered driven to achieve four-wheel-drive running of the tractor by means of a conventional four-wheel-drive device 8.
Ir. known manner, the two differentials 4 and 5 are provided with respective locking and unlocking devices, and the four-wheel-drive unit 8 is provided, also in known manner, with an engagement and disengagement device. For simplicity, these devices are not illustrated as they are well known to experts in the art and are normally operated by means of respective actuators, conventionally manually-operated solenoid valves.
According to the invention, the tractor 1 is equipped with a control device which, whilst retaining the possibility of manual operation, is arranged automatically to control the solenoid valves of the devices for engaging and disengaging the four-wheel-drive unit 8 and for locking and unlocking the differentials 4 and 5.
This device is constituted by an electronic control unit 9 constituted by a programmable microprocessor connected to a series of sensors installed on the tractor 1 and arranged to provide the control unit 9 with signals indicative of the prevailing operative conditions of the tractor. These sensors may include a steering sensor 10 associated with the steering wheel 6, an asymmetric braking sensor 11 associated with the pedal device ,, and a tractor speed sensor 12.
The control unit 9 is arranged to operate in three operating modes by means of the same number of selection buttons 13, 14 and 15. The selector 13 enables selection to be made between manual operation and automatic operation of the unit 9, and the selectors 14 and 15 respectively enable the locking or unlocking of the dIfferentIals 4 and 5 an the engagement or disengagement of the four-wheel-drive unit 8 to be carried out manually when the button 13 is in the "manual" position.
When the selection button 13 is in the "automatic" position, the operations of locking/unlocking of the differentials 4, 5 and engagement/disengagement of the four-wheel-drive unit 8 are controlled independently of the wishes of the operator, according to the principle of always ensuring maximum traction while working in the field and of automatically facilitating manoeuvring and transportating operations, which require unlocked differentials 4, 5 and/or two-wheel drive.
The electronic control unit "detects" the prevailing operating conditions of the tractor by means of the steering angle sensors 10, asymmetric braking sensors 11 and wheel-speed sensors 12 and causes, for example, disengagement of the four-wheel-drive unit 8 if the speed exceeds a certain predetermined threshold value, or unlocking of the differentials 4 and 5 if the front wheels are turned beyond a certain angle or if unilateral braking occurs.
The operating logic of the control unit 9 in the "automatic" operating mode can be illustrated by the following example.
When the selector 13 is in the "automatic" position, the four-wheel-drive unit 8 is normally engaged and the dIfferentials 4 and 5 are locked.
The differentials 4 and 5 are unlocked (reversibly) if:
- the speed of the tractor 1 is greater than a predetermined threshold value, or
- asymmetric braking occurs, or
- the steering is at an angle greater than a predetermined threshold value and the speed is simultaneously greater than a pre-established threshold value.
The four-wheel-drive unit 8 is disengaged (reversibly) if: - the speed of the tractor is greater than the predetermined threshold speed, or (optionally)
- the steering angle exceeds a predetermined threshold angle.
Naturally, the scope the present invention extends to models having equal utility by means of the same innovative concept.
Thus, for example, supplementary processors may be provided to improve the response of the system in certain operating conditions. For example, in order to avoid anomalous unlocking as a result of severe wheel-spin, protection may be provided which prevents unlocking of the differentials 4 and 5 and disengagement of the four-wheel-drive unit 8 when the acceleration of the driving wheels is greater than a predetermined threshold.
Claims (5)
1. A tractor with devices for engagement and disengagement of four-wheel drive and locking and unlocking of the front and rear differentials by means of respective electroactuators, characterised in that a control device is provided which is operatively associated with the electroactuators of the devices for engagement and disengagement of four-wheel drive and for locking and unlocking of the differentials, comprising means for sensing the operating conditions of the tractor and an electronic control unit supplied with signals from the sensor means and arranged to pilot the electroactuators; the electronic control unit being settable by means of selectors in three different operating modes, in two of which it carries out manually the operations of engagement and disengagement of four-wheel drive and locking and unlocking of the differentials respectively, and in the third of which it carries out these functions automatically in response to the signals from the sensor means.
2. A tractor according to claim 1, characterised in that the sensor means comprise a steering angle sensor, an asymmetric braking sensor and a sensor of the speed of the tractor.
3. A method for automatically controlling the devices for locking and unlocking of the front and rear differentials and/or the devices for engagement and disengagement of four-wheel drive in an agricultural tractor, characterised in that it consists of:
- setting the locking and unlocking devices and/or the engagement and disengagement devices in the condition corresponding respectively to locking of the differentials and to engagement of four-wheel drive,
- detecting the forward speed, the steering angle and the condition of asymmetric braking of the tractor, and obtaining indicative electrical signals,
- using the electrical signals automatically and reversibly to switch the locking and unlocking devices and/or the engagement and disengagement devices into the condition corresponding respectively to unlocking of the differentials and to disengagement of four-wheel drive, if the speed of the tractor is greater than a predetermined threshold value, and/or if the steering angle exceeds a predetermined threshold value, and/or even in the case of asymmetric braking.
4. A tractor substantially as hereinbefore described with reference to the accompanying drawing.
5. A method for automatically controlling the devices for locking and unlocking of the front and rear differentials and/or the devices for engagement and disengagement of four-wheel drive in an agricultural tractor, substantially as hereinbefore described with reference to the accompanying drawing.
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| IT8767893A IT1211423B (en) | 1987-10-26 | 1987-10-26 | ELECTRONIC CONTROL DEVICE FOR DOUBLE TRACTION AND DIFFERENTIALS OF A TRACTOR |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB8824942D0 GB8824942D0 (en) | 1988-11-30 |
| GB2211475A true GB2211475A (en) | 1989-07-05 |
| GB2211475B GB2211475B (en) | 1991-10-23 |
Family
ID=11306152
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB8824942A Expired - Fee Related GB2211475B (en) | 1987-10-26 | 1988-10-25 | Device for controlling the four-wheel drive and the differentials of a tractor |
Country Status (6)
| Country | Link |
|---|---|
| CH (1) | CH674491A5 (en) |
| DE (1) | DE8813401U1 (en) |
| ES (1) | ES2014707A6 (en) |
| FR (1) | FR2622159B3 (en) |
| GB (1) | GB2211475B (en) |
| IT (1) | IT1211423B (en) |
Cited By (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012161649A1 (en) * | 2011-05-23 | 2012-11-29 | BAE Systems Hägglunds Aktiebolag | Method and system for controlling a differential configuration |
| WO2012161648A1 (en) * | 2011-05-23 | 2012-11-29 | BAE Systems Hägglunds Aktiebolag | Method and system for controlling a differential configuration |
| EP3221175A1 (en) * | 2014-11-19 | 2017-09-27 | Jaguar Land Rover Limited | Control system and method of controlling a driveline |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI90219C (en) * | 1990-05-14 | 1994-01-10 | Valmet Traktori Oy | Method and system for automatically engaging / disengaging the transmission of the front axle of a tractor or implement |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2181395A (en) * | 1985-10-12 | 1987-04-23 | Kubota Ltd | Two/four wheel drive system |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS59176121A (en) * | 1983-03-24 | 1984-10-05 | Kubota Ltd | Front wheel drive control unit for 4-wheel-drive car |
| DE3338940A1 (en) * | 1983-10-27 | 1985-05-09 | Klöckner-Humboldt-Deutz AG, 5000 Köln | ARMED TRACTOR WITH TWO DRIVABLE AXLES WITH DIFFERENTIAL GEARBOXES |
| DE3425691A1 (en) * | 1984-07-12 | 1986-01-23 | Klöckner-Humboldt-Deutz AG, 5000 Köln | DEVICE FOR MOLDING OR FORCE-ENDING A DIFFERENTIAL LOCK |
-
1987
- 1987-10-26 IT IT8767893A patent/IT1211423B/en active
-
1988
- 1988-10-19 CH CH3901/88A patent/CH674491A5/it not_active IP Right Cessation
- 1988-10-25 ES ES8902306A patent/ES2014707A6/en not_active Expired - Lifetime
- 1988-10-25 FR FR8813941A patent/FR2622159B3/en not_active Expired
- 1988-10-25 GB GB8824942A patent/GB2211475B/en not_active Expired - Fee Related
- 1988-10-25 DE DE8813401U patent/DE8813401U1/en not_active Expired
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2181395A (en) * | 1985-10-12 | 1987-04-23 | Kubota Ltd | Two/four wheel drive system |
Cited By (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| WO2012161649A1 (en) * | 2011-05-23 | 2012-11-29 | BAE Systems Hägglunds Aktiebolag | Method and system for controlling a differential configuration |
| WO2012161648A1 (en) * | 2011-05-23 | 2012-11-29 | BAE Systems Hägglunds Aktiebolag | Method and system for controlling a differential configuration |
| EP3221175A1 (en) * | 2014-11-19 | 2017-09-27 | Jaguar Land Rover Limited | Control system and method of controlling a driveline |
| EP3221175B1 (en) * | 2014-11-19 | 2024-04-17 | Jaguar Land Rover Limited | Control system and method of controlling a driveline |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2622159A3 (en) | 1989-04-28 |
| CH674491A5 (en) | 1990-06-15 |
| DE8813401U1 (en) | 1989-01-05 |
| FR2622159B3 (en) | 1989-11-17 |
| GB2211475B (en) | 1991-10-23 |
| GB8824942D0 (en) | 1988-11-30 |
| IT8767893A0 (en) | 1987-10-26 |
| ES2014707A6 (en) | 1990-07-16 |
| IT1211423B (en) | 1989-10-18 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20051025 |