GB2128947A - Vehicle steering system - Google Patents
Vehicle steering system Download PDFInfo
- Publication number
- GB2128947A GB2128947A GB08230277A GB8230277A GB2128947A GB 2128947 A GB2128947 A GB 2128947A GB 08230277 A GB08230277 A GB 08230277A GB 8230277 A GB8230277 A GB 8230277A GB 2128947 A GB2128947 A GB 2128947A
- Authority
- GB
- United Kingdom
- Prior art keywords
- steering
- wheel means
- displacement
- neutral condition
- vehicle
- 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.)
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D7/00—Steering linkage; Stub axles or their mountings
- B62D7/06—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins
- B62D7/14—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering
- B62D7/15—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels
- B62D7/1554—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels comprising a fluid interconnecting system between the steering control means of the different axles
- B62D7/1572—Steering linkage; Stub axles or their mountings for individually-pivoted wheels, e.g. on king-pins the pivotal axes being situated in more than one plane transverse to the longitudinal centre line of the vehicle, e.g. all-wheel steering characterised by means varying the ratio between the steering angles of the steered wheels comprising a fluid interconnecting system between the steering control means of the different axles provided with electro-hydraulic control means
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- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Steering-Linkage Mechanisms And Four-Wheel Steering (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
Abstract
A vehicle steering system includes first steerable ground wheels 1 (in side view) displaceable by a steering gear 3 from a first neutral condition for effecting a steering manoeuvre in response to a steering input, and second steerable ground wheels 2 (in plan view) displaceable by a ram 13. An electrical control system for the ram 13 is responsive through a sensor 22 to the displacement of the wheels 1 and through a sensor 23 to the displacement of the wheels 2 and includes a processor 20. The processor 20 co-relates signals from the sensors 22 and 23 to provide a control signal to an electrical control valve 16 for the ram 13 whereby during a steering manoeuvre of the wheels 1 through a predetermined steering angle from a neutral condition, the wheels 2 are retained by the ram 13 in a neutral condition, and when the wheels 1 are displaced beyond said predetermined steering angle, the ram 13 displaces the wheels 2 into a steering position which, together with the steering position of the wheels 1, facilitates manoeuvring of the vehicle. The control system may include a sensor 37 responsive to vehicle speed whereby when the vehicle speed exceeds a predetermined value the valve 16 is actuated and the ram 13 controls displacement of the wheels 2 to position and retain those wheels in their neutral condition. <IMAGE>
Description
SPECIFICATION
A vehicle steering system and a vehicle which includes such a system
This invention concerns a steering system which is primarily intended for use with large or heavy duty vehicles such as coaches, lorries or trucks, buses, tankers, mobile cranes and the ike to facilitate the manoeuvrability of such vehicles.
With large or heavy duty vehicles of the kind mentioned it has hitherto been proposed to provide two or more sets of steerable road wheels where the axles of the wheel sets are linked together for displacement in unison and in response to a steering input. This type of steering system is commonly referred to as multi-axle steering and is usually power assisted. Examples of multi-axle steering are to be found in our British Patents Nos.
1,387,893 and 1,291,152. In the multi-axle steering system of British Patent No.
1,291,1 52 the assistance to any individual steering axle is directly proportional to the steering load or resistance to turning experienced by that axle at any particular time. A further example of multi-axle steering is disclosed in British Patent No. 1,099,979 in which two separate power steering mechanisms of conventional type are interconnected through a linkage which effects simultaneous operation of the sets of steerable wheels.
Because of the simultaneous displacement of the steerable road wheels in the two or more sets it has been necessary for the wheels in their sets to be positioned close to each other so that the direction of steering for the wheels in the respective sets is substantially common; whilst the provision of several sets of steerable wheels in multi-axle steering improves the load carrying capacity and possibly the traction of the vehicle, there is little or no improvement in the manoeuvrability of the vehicle as compared with a similarly sized vehicle having a single set of steerable road wheels.It is an object of the present invention to provide a vehicle system having what may conveniently be regarded as multi-axle steering and which provides an improved manoeuvring facility, particularly but. not essentially for large or heavy duty slow moving vehicles and which lends itself to the use of a coupling arrangement between the sets of steerable road wheels which alleviates the likelihood of the coupling being damaged by external hazards such as uneven road surfaces or obstructions.
According to the present invention there is provided a vehicle steering system which comprises first ground engaging wheel means displaceable from a predetermined first neutral condition for effecting a steering manoeuvre; second ground engaging wheel means spaced from said first means and displaceable for steering from a predetermined second neutral condition; steering means for displacing the first wheel means in response to a steering input, and a control system for displacing the second wheel means, said control system being responsive to the displacement of the first wheel means and being arranged so that during a steering manoeuvre of the first wheel means through a predetermined steering angle from the first neutral condition, the second wheel means is retained in the second neutral condition, and when the first wheel means is displaced beyond said predetermined steering angle from the first neutral condition, the control system displaces the second wheel means from the second neutral condition and into a steering position which, together with the steering position of the first wheel means, facilitates manoeuvring of the vehicle.
The first and second ground engaging wheel means will usually each comprise one or more sets of ground engaging wheels which are displaceable in unison to effect a steering manoeuvre and where a set of wheels may be regarded as two or more wheels on what may be conveniently considered a common axle. It will be appreciated however that one or other of the ground engaging wheel means may consist of a single displaceable wheel.By the present invention the first and second wheel means may be spaced a considerable distance from each other on the vehicle so that when applied to a conventional bus, coach, truck or lorry structure where the vehicle extends in the fore/aft direction parallel to that in which it is intended to be steered straight, the first and second wheel means will be spaced longitudinally of the fore/aft direction with their respective neutral conditions being when the wheels are positioned respectively to steer in the fore/aft direction.From the aforegoing statement of our invention it will be seen that the second wheel means is retained in its neutral condition irrespective of a steering manoeuvre which is applied to the first wheel means for so long as that steering manoeuvre does not displace the first wheel means beyond a predetermined steering angle; this permits the vehicle to be steered and manoeuvred in conventional manner.
However, if the predetermined steering angle is exceeded as the first wheel means are displaced from their neutral condition and towards one or other full steering lock, the control system causes the second wheel means to be displaced from their neutral condition and in a sense which, bearing in mind the orientation of the first wheel means, facilitates manoeuvring of the vehicle. This concept of steering is believed to be particularly advantageous for slow speed manoeuvring of large or heavy duty vehicles as permitting small turning circles whilst alleviating wear and tear on the second wheel means which, in conventional steering systems, would be subjected to high frictional or drag forces and scuffing of tyres.The extent of, and direction in which, the second wheel means are displaced will depend upon the design and structure of the vehicle to which the steering system is applied; however, for conventional forms of large transport vehicles such as coaches, buses, trucks and the like it is envisaged that the second wheel means will be displaced, in plan, in a direction which is contra to the direction in which the first wheel means are displaced and to an extent so that the first and second ground engaging wheel means generally follow a common steering arc.Alternatively for vehicles of a more specialised nature, such as heavy duty mobile cranes, hoists and container lifting devices, the second wheel means may be displaced, in plan, in the same direction of steering as the first wheel means and to a similar extent so that both the first and second wheel means steer in a generally parallel direction for the vehicle to exhibit what may be regarded as crab-wise or sideways movement. The first ground engaging wheel means will usually be capable of displacement from the first neutral condition and towards one or other of its full steering locks through a steering angle which is considerably greater than the aforementioned predetermined steering angle.Preferably the control system is arranged to displace the second wheel means to an extent which maintains the optimum steering characteristics of the vehicle (as provided by both the first and second wheel means) and so that while the first wheel means exceeds the predetermined steering angle, the first and second wheel means are displaced in sympathy with each other. Furthermore, the control system is preferably arranged so that when the first wheel means is displaced from a position where the predetermined steering angle is exceeded and towards the first neutral condition (so that the first wheel means moves into a position where the steering angle is less than the predetermined steering angle) the second wheel means is automatically displaced into and retained at the second neutral condition.
Preferably the control system comprises means which is responsive to vehicle speed and which acts to position and retain the second ground engaging wheel means in the second neutral condition when the vehicle speed exceeds a predetermined value. Such speed responsive means which may react at, say, a speed of 5 to 10 m.p.h., is most advisable when the steering system is applied to vehicles capable of relatively high travelling speeds such as buses, coaches, and trucks to prevent undesirable and what could be hazardous displacement of the second wheel means during a steering manoeuvre at high speed. For conventionally slow moving vehicles such as mobile cranes and hoists it may be unnecessary for the control system to be vehicle speed responsive.In the light of the aforegoing comments, there is further provided according to the present invention a vehicle steering system which comprises first ground engaging wheel means displaceable from a predetermined first neutral condition for effecting a steering manoeuvre; second ground engaging wheel means spaced from said first means and displaceable for steering from a predetermined second neutral condition; steering means for displacing the first wheel means in response to a steering input, and a control system for displacing the second wheel means to facilitate, together with displacement of the first wheel means, manoeuvring of the vehicle, said control system comprising means which is responsive to vehicle speed and which means positions and retains the second wheel means in the second neutral condition when the vehicle speed exceeds a predetermined value.The control system preferably comprises a vehicle speed sensor which provides a predetermined output or other response when the speed exceeds said predetermined value and which response is utilised in determining the displacement and such re-positioning of the second wheel means as may-be necessary. The- control system also preferably comprises a steering sensor which detects the displacement of the first wheel means from the first neutral condition and provides an output or other response when that displacement exceeds the predetermined steering angle for use in determining the displacement of the second wheel means.
The steering means will usually comprise a steering gear and a steering linkage for the first wheel means and the steering sensor may be responsive to displacement of a part of that gear or linkage in response to a steering input. Still further, the control system preferably comprises a positioning sensor which detects displacement of the second wheel means from the second neutral condition and provides an output or other response for use in determining the subsequent displacement which may be required of the second wheel means.
It is a preferred feature of the present invention that the control system includes an electrical system which links the first and second wheel means through a processor and which co-relates signals or other electrical responses applied thereto as a result of displacement of the first ground engaging wheel means (and as a result of such displacement as may be applied to the second ground engaging wheel means) to provide an output signal or other response which causes such displacement as may be required to the second wheel means.The processor in the electrical system may also be subjected to an input from a vehicle speed sensor as previ ously mentioned when such a sensor is incorporated within the control system to ensure that the output from the processor will be such as to position and retain the second wheel means in their second neutral condition when the vehicle speed exceeds a predetermined value. With such an electrical system as part of the control system, the outputs or responses resulting from the steering sensor, the positioning sensor and, when provided, the vehicle speed sensor, are conveniently electrical signals which are applied direct to the processor.The linking of the first and second wheel means electrically has the advantage that they can be spaced at a considerable distance from each other with the wiring unobtrusively positioned and protected (unlike mechanical linkages which are provided between wheel sets in conventional multi-axle steering systems).
The displacement of the second wheel means may be effected by a motor which may be regarded as forming part of the control system and is controlled in response to an input which is determined, at least in part, from displacement of the first wheel means.
Preferably the control of the motor is effected by an output signal derived from the aforementioned processor. Large or heavy duty vehicles incorporating the steering system of the present invention will usually be provided with a hydraulically power assisted steering gear for the first wheel means and preferably the motor for displacing the second wheel means is hydraulically actuated, conveniently in a hydraulic system which is common to the power assisted steering gear. The motor may be in the form of a piston and cylinder or ram device to which hydraulic fluid is directed by way of a valve which is responsive to the inputs as previously mentioned for determining the displacement or retention that is required of the second wheel means.With the electrical system and processor as previously discussed the valve is conveniently of the solenoid type which is responsive to an electrical signal from the processor to provide the required control to the hydraulic motor.
Still further there is provided a vehicle which includes a steering system as specified above as being in accordance with the present invention. Usually the vehicle will extend in the fore/aft direction parallel to that in which it is intended to be steered straight and preferably the first and second wheel means are spaced longitudinally in the fore/aft direction and so that their respective neutral conditions are when said wheel means are positioned respectively to steer in the fore/aft direction.
Usually, but not essentially, the second set of wheel means will be displaced, in plan, in a contra direction to the direction in which the first set of wheel means are displaced so that the first and second wheel means steer generally along a common arc.
One embodiment of a vehicle steering system constructed in accordance with the present invention will now be described, by way of example only, with reference to the accompanying schematic drawing, in which, for convenience of illustration, one of a set of ground engaging steerable wheels is shown in side view while one of a second set of ground engaging displaceable wheels is shown in plan view.
The steering system illustrated is intended to be applied to a long wheel base vehicle such as a bus, coach or truck having longitudinally spaced front steerable road wheels 1 (one of which is shown in side view) and rear displaceable road wheels 2 (one of which is shown in plan view). Conveniently the road wheels 1 and 2 may each be regarded as a pair of wheels on a common axle. The front wheels 1 have what may be regarded as a conventional power assisted steering gear 3 comprising a drop arm 3a which is connected through a drag link 4 for steering a road wheel 1. The gear 3 may be of the worm and sector type where rotation of the worm by a steering input applied through a steering column 5 displaces the sector arcuately and therethrough the drop arm 3a and drag link 4 to effect a steering manoeuvre.Power assistance is provided by hydraulic pressure applied to a ram within the gear 3 under control of a torque responsive open-centre valve 6 fluid pressure supply to which is provided by a pump 7 and conduit 8 while a conduit 9 provides a fluid return from the open centre valve 6 to a reservoir 10.
The rear axle 11 for the wheels 2 is pivotally mounted at 1 2 about a vertical axis for displacement of the rear wheels in a horizontal plane. Displacement of the axle 11 is controlled by a hydraulic motor in the form of a ram 1 3 coupled to a steering lever 14 of the axle. Extension and contraction of the ram 1 3 is effected by hydraulic fluid pressure supplied to and exhausted from opposed chambers in the ram through conduits 14 and 1 5 under control of a closed-centre spool valve 1 6.
Hydraulic fluid supply to and return from the valve 16 is by way of conduits 17 and 18 coupled respectively to the output from the pump 7 and the reservoir 10.
In the present example, the front wheels 1 and rear wheels 2 have a common neutral condition which corresponds to each set of wheels being positioned by the steering gear 3 and ram 1 3 respectively to provide steering along a common line which is parallel to the fore/aft or longitudinal direction of the vehicle. Displacement of the wheels 1 for steering is effected in conventional manner by a steering input applied through the column 5 and gear 3. However, displacement of the rear wheels 2 about the vertical axis 1 2 to provide a steering-like effect is controlled automatically in response, in part, to the steer ing which is applied to the front wheels 1.To provide control for displacement of the rear wheels 2 there is provided an electrical system 19 which effectively links the front and rear wheels and forms part of a control system for displacing the rear wheels 2, the control system also including the spool valve 16 and ram 1 3. The electrical system 1 9 includes a micro processor 20 and is powered by a direct current source 21.The processor 20 co-relates signals derived as a result of adjustment in a steering sensor 22 associated with the steering gear 3 and a positioning sensor 23 associated with the rear axle 11 and provides an output signal through a circuit part 24 to an electric actuator such as a solenoid 25 for controlling operation of the spool valve 16 and thereby the flow of fluid to and from the ram 1 3. The steering sensor 22 includes a movable electrical contact or brush 26 which is coupled to the drop arm 3a to be arcuately displaceable therewith; the brush 26 connects to the processor 20 by way of a line 27. Associated with the brush 26 is an arcuate circuit part 28 of a variable resistance circuit 29 to the processor 20.The extent of arcuate sweep of the brush 26 over the circuit part 28 corresponds to the arcuate displacement of the drop arm 3a during a steering manoeuvre from one full lock to the other of the road wheels 1 (the full arcuate displacement of the brush 26 is indicated by the arrows 30). With the wheels 1 in their neutral condition the brush 26 engages the circuit part 28 symmetrically between the ends of the arc 30 and the centrally disposed region 31 of the arcuate circuit part 28 is of negligible resistance; however, the end regions 32 of the arcuate circuit part 28 provide high resistance tracks over which the brush 26 sweeps as the wheels 1 are displaced towards one or other of their full steering lock conditions.With the steering sensor 22 as described above, when the electrical system is energised, the processor 20 can be arranged so that while the brush 26 contacts the low resistance arcuate part 31 no signal, or a predetermined constant signal, is derived by way of the lines 27 and 29; however, upon the brush 26 moving into contact with one or other of the high resistance end tracks 32, there will be a change in resistance resulting in a signal or change in signal to the processor 20 and it is this signal or change in signal from a predetermined signal which is intended to be applied for effecting control in displacement of the rear wheels 2.
The positioning sensor 23 for the rear wheel axle 11 comprises a movable electrical contact or brush 33 connected by a conduit 34 to the processor 20 and arcuately displaceable about a vertical axis in unison with displacement of the axle 11. The brush 33 contacts and sweeps over an arcuate resistance track 35 in a circuit 36 to the micro processor. When the rear wheels 2 are in their neutral condition the brush 33 contacts the resistance track 35 centrally and zero signal or a predetermined constant signal is applied to the processor 20 through the conduits 34 and 36. However, upon displacement of the axle 11 about the vertical axis and in response to extension or contraction of the ram 13, the brush 33 will sweep over the resistance track 35 to cause a signal to be applied to the processor or a variation in signal from the aforementioned predetermined signal.
When both the front and rear wheels 1 and 2 are in their neutral condition for steering the vehicle straight the electrical system may be regarded as balanced whereby the lack of signals or constant signals provided from the sensors 22 and 23 are assessed by the micro processor 20 with the result that a signal is not applied to the solenoid 25 through the circuit part 24. The spool valve 1 6 consequently is maintained in its closed centre condition whereby fluid flow is cut-off to and from the ram 1 3 (thereby hydraulically locking the wheels 2 in their neutral condition). This balanced condition of the electrical system will be maintained for so long as the brush 26 contacts the low resistance arcuate circuit part 31.However, if the steering applied to the front wheels 1 displaces those wheels beyond a predetermined steering angle which corresponds to the extent of the low resistance part 31, the brush 26 will move onto one or other of the high resistance tracks 32 depending upon the direction of steering and thereby cause a variation in signal to the processor 20 through the conduits 27 and 29. This causes an imbalance in the processor 20 which is corelated with the signal derived from the positioning sensor 23 and a signal is applied in the appropriate direction through the circuit part 24 to the solenoid controlled spool valve
16.As a result the ram 1 3 is actuated to displace the axle 11 until the variation effected by the brush 33 on the resistance 35 causes the electrical system to be balanced by the processor 20 and the solenoid 25 is deenergised to maintain the ram 13 in the required extended or contracted condition consistent with the rear wheels 2 being displaced into a steering position which, together with the steering wheels 1, facilitates manoeuvring of the vehicle. With a vehicle of the type to which the present example is directed the rear wheels 2 will usually be displaced in a direction which, in plan, is contra to the direction in which the front wheels 1 are displaced and to an extent whereby the front and rear wheels may steer along an arc which
may be regarded as common to both sets of wheels. When a steering manoeuvre resulting
in displacement of the rear wheels 2 has been completed and as the front wheels 1 are "straightened-out' ', the brush 26 will eventually move into contact with the low resistance circuit part 31 causing the micro processor 20 to detect an imbalance in the system and react accordingly to control the solenoid spool valve 16 and displace the ram 1 3 for the wheels 2 to adopt their neutral condition. It will be appreciated that the extent of displacement of the rear wheels 2 from their neutral condition will be varied in accordance with the variation in resistance provided in the respective circuit parts which include the resistances 32 and 35 and as co-related by the processor 20 to provide optimum steering conditions.
The steering system as above described and when the rear wheels 2 are displaced from their neutral condition as the front wheels 1 approach one or other of their full lock positions is primarily intended to facilitate low speed manoeuvring of the vehicle--say when the vehicle is travelling at speeds less than 10 m.p.h. In the present example it is envisaged that the vehicle to which the system is fitted is capable of much higher speeds where it is realised that the displacement of the rear wheels 2 from their neutral condition during high speed manoeuvring is likely to be hazardous. To alleviate this problem the electrical system 1 9 includes a speed sensor 37 which is in circuit 38 with the processor and which is responsive to vehicle speed to provide an electrical signal to the processor 20 which is dependent upon the vehicle speed.When the vehicle speed exceeds a predetermined value, which may be in the order of 5 to 10 m.p.h., the signal from the speed sensor 37 is assessed by the processor 20 which latter provides an output through the circuit part 24 and controls the spool valve 16 to close off fluid flow to and from the ram 1 3 (assuming that the wheels 2 are in their neutral condition) and thereby hydraulically lock the wheels 2 against displacement for so long as the vehicle speed exceeds the predetermined value.Alternatively, assuming that the wheels
2 are displaced from their neutral condition when the vehicle speed exceeds the predeter
mined value, the micro processor 20 co-re
lates the input from the speed sensor 37 and from the positioning sensor 33 to provide the output to the circuit part 24 in a sense which controls the spool valve 1 6 to actuate the ram 1 3 for the wheels 2 to be-displaced to their
neutral condition prior to closing the valve 16 for fluid flow to the ram 1 3 In the event of an electrical failure in the
steering system there is preferably a fail-safe
provision whereby the rear wheels 2 automati
cally revert to their neutral condition (if dis
placed therefrom upon the electrical failure)
and the spool valve 16 automatically reverts to its closed centre condition to hydraulically
lock the ram 1 3.
A detailed discussion of the electrical cir
cuitry for the micro processor 20 and the
speed sensor 37 has not been given since it is
realised that the structure and arrangement of these components will readily be apparent to persons skilled in the art and having an understanding of the present invention. It will also
be realised that alternative forms of steering
and positioning sensors 22 and 23 can be
used other than the potentiometer types discussed above.
Claims (18)
1. A vehicle steering system which com
prises first ground engaging wheel means
displaceable from a predetermined first neutral condition for effecting a steering manoeuvre; second ground engaging wheel means spaced
from said first means and displaceable for
steering from a predetermined second neutral
condition; steering means for displacing the
first wheel means in response to a steering
input, and a control system for displacing the
second wheel means, said control system be
ing responsive to the displacement of the first
wheel means and being arranged so that
during a steering manoeuvre of the first wheel
means through a predetermined steering
angle from the first neutral condition, the
second wheel means is retained in the second
neutral condition, and when the first wheel
means is displaced beyond said predeter
mined steering angle from the first neutral
condition, the control system displaces the
second wheel means from the second neutral
condition and into a steering position which,
together with the steering position of the first
wheel means, facilitates manoeuvring of the
vehicle.
2. A system as claimed in claim 1 in
which the control system is arranged so that
when the first wheel means is displaced from
a position where the predetermined steering
angle is exceeded and towards the first neu
tral condition whereby the first wheel means
are disposed at a steering angle less than said
predetermined steering angle, the second
wheel means are automatically displaced into
and retained at the second neutral condition.
3. A system as claimed in either claim 1
or claim 2 in which the control system com
prises means which is responsive to vehicle
speed and which acts to position and retain
the second wheel means in the second neutral
condition when the vehicle speed exceeds a
predetermined value.
4. A system as claimed in claim 3 in
which the control system comprises a vehicle speed sensor which provides a predetermined
response when the vehicle speed exceeds said
predetermined value and which response is
utilised in determining the displacement and
such re-positioning of the second wheel
means as may be necessary.
5. A system as claimed in any one of the
preceding claims in which the control system
comprises a steering sensor which detects the
displacement of the first wheel means from the first neutral condition and provides a
response when that displacement exceeds the
predetermined steering angle for use in deter
mining the displacement of the second wheel
means.
6. A system as claimed in claim 5 in
which the steering means comprises a steer
ing gear and a steering linkage for the first
wheel means and the steering sensor is re
sponsive to displacement of a part of that gear
or linkage in response to a steering input.
7. A system as claimed in any one of the
preceding claims in which the control system
comprises a positioning sensor which detects
displacement of the second wheel means from
the second neutral condition and provides a
response for use in determining the subse
quent displacement which may be required of
the second wheel means.
8. A system as claimed in any one of the
preceding claims in which the control system
includes an electrical system which links the
first and second wheel means through a pro
cessor and which co-relates electrical re
sponses applied thereto as a result of displace
ment of the first wheel means to control
displacement or positioning of the second
wheel means.
9. A system as claimed in claim 8 when
appendant to any one of claims 4 to 7 in
which the processor is subjected to an electri
cal input from the sensor or sensors and
provides an output for controlling the dis
placement or positioning of the second wheel
means.
10. A system as claimed in any one of the
preceding claims in which the control system
comprises a motor for effecting displacement
of the second wheel means, said motor being
controlled in response to an input which is
determined, at least in part, from displace
ment of the first wheel means.
11. A system as claimed in claim 10
when appendant to claim 9 in which the
motor is controlled by the output from the
processor.
12. A system as claimed in the claim 11
in which the motor is hydraulically actuated
under control of an electrically operated valve,
said valve being controlled by the output from the processor.
1 3. A system as claimed in claim 1 2 in
which the steering means comprises a hydrau
lically power assisted steering gear and
wherein said gear and motor form part of a
common hydraulic system.
14. A vehicle steering system which com
prises first ground engaging wheel means
displaceable from a predetermined first neutral
condition for effecting a steering manoeuvre;
second ground engaging wheel means spaced
from said first means and displaceable for
steering from a predetermined second neutral
condition; steering means for displacing the
first wheel means in response to a steering input, and a control system for displacing the second wheel means to facilitate, together with displacement of the first wheel means, manoeuvring of the vehicle, said control system comprising means which is responsive to vehicle speed and which means positions and retains the second wheel means in the second neutral condition when the vehicle speed exceeds a predetermined value.
1 5. A vehicle steering means as claimed in either claim 1 or claim 14 and substantially as herein described with reference to the accompanying illustrative drawing.
1 6. A vehicle which includes a steering system as claimed in any one of the preceding claims.
1 7. A vehicle as claimed in claim 1 6 and which extends in the fore/aft direction parallel to that in which it is intended to be steered straight, and wherein the first and second wheel means are spaced longitudinally in the fore/aft direction and are arranged so that their respective neutral conditions are when said wheel means are positioned respectively to steer in the fore/aft direction.
18. A vehicle as claimed in claim 1 7 in which the second wheel means are displaced in response to displacement of the first wheel means in a direction which, in plan, is contra to the direction in which the first wheel means is displaced.
Priority Applications (3)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08230277A GB2128947B (en) | 1982-10-22 | 1982-10-22 | Vehicle steering system |
| DE19833338011 DE3338011A1 (en) | 1982-10-22 | 1983-10-19 | STEERING SYSTEM FOR HEAVY VEHICLES |
| FR8316840A FR2534866A1 (en) | 1982-10-22 | 1983-10-21 | VEHICLE STEERING SYSTEM AND VEHICLE USING THE SAME |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB08230277A GB2128947B (en) | 1982-10-22 | 1982-10-22 | Vehicle steering system |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| GB2128947A true GB2128947A (en) | 1984-05-10 |
| GB2128947B GB2128947B (en) | 1986-03-12 |
Family
ID=10533795
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB08230277A Expired GB2128947B (en) | 1982-10-22 | 1982-10-22 | Vehicle steering system |
Country Status (3)
| Country | Link |
|---|---|
| DE (1) | DE3338011A1 (en) |
| FR (1) | FR2534866A1 (en) |
| GB (1) | GB2128947B (en) |
Cited By (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2157242A (en) * | 1984-02-28 | 1985-10-23 | Mitsubishi Motors Corp | Front and rear wheel steering apparatus |
| GB2158788A (en) * | 1984-05-05 | 1985-11-20 | Trw Cam Gears Ltd | Power assistance steering systems for vehicles |
| EP0243180A2 (en) * | 1986-04-22 | 1987-10-28 | Mitsubishi Denki Kabushiki Kaisha | Motor-driven power steering system for front and rear road wheels |
| GB2208282A (en) * | 1987-07-21 | 1989-03-22 | Bamford Excavators Ltd | Materials handling vehicle |
| US5448480A (en) * | 1988-05-11 | 1995-09-05 | Siemens Aktiengesellschaft | Fail-safe operation via controller redundancy for steering the back wheels of a road vehicle |
Families Citing this family (4)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| DE3413007A1 (en) * | 1984-04-06 | 1985-10-17 | Audi AG, 8070 Ingolstadt | STEERING DEVICE FOR A MOTOR VEHICLE |
| DE3813691A1 (en) * | 1988-04-22 | 1989-11-02 | Rexroth Mannesmann Gmbh | Inductive sensor |
| DE19801590A1 (en) * | 1998-01-17 | 1999-07-22 | Man Nutzfahrzeuge Ag | Heavy duty truck with at least two front axles with steerable wheels |
| DE10052339B4 (en) * | 2000-10-21 | 2009-11-26 | Man Nutzfahrzeuge Ag | Auxiliary steering device of a vehicle axle |
Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB337411A (en) * | 1929-07-26 | 1930-10-27 | Charles Denniston Burney | Improvements in or relating to the steering of motor road vehicles |
| GB523656A (en) * | 1938-10-17 | 1940-07-19 | William Martin Blagden | Improvements in or relating to steering mechanism for motor vehicles |
| GB1194744A (en) * | 1967-11-29 | 1970-06-10 | Massey Ferguson Perkins Ltd | Improved Steering Arrangement for Wheeled Vehicles |
| US4105086A (en) * | 1975-11-13 | 1978-08-08 | Takemochi Ishii | System for controlling vehicular four-wheel steering mechanisms |
| GB1550349A (en) * | 1976-10-29 | 1979-08-15 | County Commercial Cars Ltd | Steering mechanisms for four wheel drive vehicles |
| GB2044699A (en) * | 1978-12-29 | 1980-10-22 | Honda Motor Co Ltd | Steering apparatus for vehicles |
| GB1581556A (en) * | 1976-12-31 | 1980-12-17 | Tapp G E E | Steering mechanisms |
Family Cites Families (5)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US3323610A (en) * | 1965-09-22 | 1967-06-06 | Caterpillar Tractor Co | Hydraulic steering of forward and rear vehicle wheels |
| GB1291152A (en) * | 1970-06-09 | 1972-10-04 | Cam Gears Ltd | Multi-axle power-assisted steering |
| GB1387893A (en) * | 1972-11-07 | 1975-03-19 | Cam Gears Ltd | Multi-axle power-assisted steering |
| JPS5711173A (en) * | 1980-06-24 | 1982-01-20 | Nissan Motor Co Ltd | Method of controlling steering angle for vehicle capable of steering two sets of wheels |
| JPS5787759A (en) * | 1980-11-18 | 1982-06-01 | Nissan Motor Co Ltd | Method of steering vehicle |
-
1982
- 1982-10-22 GB GB08230277A patent/GB2128947B/en not_active Expired
-
1983
- 1983-10-19 DE DE19833338011 patent/DE3338011A1/en not_active Withdrawn
- 1983-10-21 FR FR8316840A patent/FR2534866A1/en not_active Withdrawn
Patent Citations (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB337411A (en) * | 1929-07-26 | 1930-10-27 | Charles Denniston Burney | Improvements in or relating to the steering of motor road vehicles |
| GB523656A (en) * | 1938-10-17 | 1940-07-19 | William Martin Blagden | Improvements in or relating to steering mechanism for motor vehicles |
| GB1194744A (en) * | 1967-11-29 | 1970-06-10 | Massey Ferguson Perkins Ltd | Improved Steering Arrangement for Wheeled Vehicles |
| US4105086A (en) * | 1975-11-13 | 1978-08-08 | Takemochi Ishii | System for controlling vehicular four-wheel steering mechanisms |
| GB1550349A (en) * | 1976-10-29 | 1979-08-15 | County Commercial Cars Ltd | Steering mechanisms for four wheel drive vehicles |
| GB1581556A (en) * | 1976-12-31 | 1980-12-17 | Tapp G E E | Steering mechanisms |
| GB2044699A (en) * | 1978-12-29 | 1980-10-22 | Honda Motor Co Ltd | Steering apparatus for vehicles |
Cited By (8)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4884647A (en) * | 1983-11-21 | 1989-12-05 | Mitsubishi Jidosha Kogyo Kabushiki Kaisha | Rear wheel steering apparatus |
| GB2157242A (en) * | 1984-02-28 | 1985-10-23 | Mitsubishi Motors Corp | Front and rear wheel steering apparatus |
| GB2158788A (en) * | 1984-05-05 | 1985-11-20 | Trw Cam Gears Ltd | Power assistance steering systems for vehicles |
| EP0243180A2 (en) * | 1986-04-22 | 1987-10-28 | Mitsubishi Denki Kabushiki Kaisha | Motor-driven power steering system for front and rear road wheels |
| EP0243180A3 (en) * | 1986-04-22 | 1989-06-28 | Mitsubishi Denki Kabushiki Kaisha | Motor-driven power steering system for front and rear road wheels |
| GB2208282A (en) * | 1987-07-21 | 1989-03-22 | Bamford Excavators Ltd | Materials handling vehicle |
| GB2208282B (en) * | 1987-07-21 | 1991-09-18 | Bamford Excavators Ltd | Materials handling vehicle |
| US5448480A (en) * | 1988-05-11 | 1995-09-05 | Siemens Aktiengesellschaft | Fail-safe operation via controller redundancy for steering the back wheels of a road vehicle |
Also Published As
| Publication number | Publication date |
|---|---|
| FR2534866A1 (en) | 1984-04-27 |
| GB2128947B (en) | 1986-03-12 |
| DE3338011A1 (en) | 1984-04-26 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| 746 | Register noted 'licences of right' (sect. 46/1977) | ||
| PCNP | Patent ceased through non-payment of renewal fee |