CA1239331A - Method and apparatus for selective supplementary hydraulic driving of the wheels of a vehicle - Google Patents
Method and apparatus for selective supplementary hydraulic driving of the wheels of a vehicleInfo
- Publication number
- CA1239331A CA1239331A CA000462389A CA462389A CA1239331A CA 1239331 A CA1239331 A CA 1239331A CA 000462389 A CA000462389 A CA 000462389A CA 462389 A CA462389 A CA 462389A CA 1239331 A CA1239331 A CA 1239331A
- Authority
- CA
- Canada
- Prior art keywords
- pressure
- working fluid
- control
- engine
- output
- 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.)
- Expired
Links
Classifications
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/42—Control of exclusively fluid gearing hydrostatic involving adjustment of a pump or motor with adjustable output or capacity
- F16H61/431—Pump capacity control by electro-hydraulic control means, e.g. using solenoid valves
-
- 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
- B60K17/00—Arrangement or mounting of transmissions in vehicles
- B60K17/04—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing
- B60K17/10—Arrangement or mounting of transmissions in vehicles characterised by arrangement, location, or kind of gearing of fluid 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
- B60K17/00—Arrangement or mounting of transmissions in vehicles
- B60K17/34—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles
- B60K17/356—Arrangement or mounting of transmissions in vehicles for driving both front and rear wheels, e.g. four wheel drive vehicles having fluid or electric motor, for driving one or more wheels
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H61/00—Control functions within control units of change-speed- or reversing-gearings for conveying rotary motion ; Control of exclusively fluid gearing, friction gearing, gearings with endless flexible members or other particular types of gearing
- F16H61/38—Control of exclusively fluid gearing
- F16H61/40—Control of exclusively fluid gearing hydrostatic
- F16H61/46—Automatic regulation in accordance with output requirements
- F16H61/468—Automatic regulation in accordance with output requirements for achieving a target input torque
-
- F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
- F16—ENGINEERING ELEMENTS AND UNITS; GENERAL MEASURES FOR PRODUCING AND MAINTAINING EFFECTIVE FUNCTIONING OF MACHINES OR INSTALLATIONS; THERMAL INSULATION IN GENERAL
- F16H—GEARING
- F16H59/00—Control inputs to control units of change-speed-, or reversing-gearings for conveying rotary motion
- F16H59/36—Inputs being a function of speed
- F16H59/46—Inputs being a function of speed dependent on a comparison between speeds
- F16H2059/465—Detecting slip, e.g. clutch slip ratio
- F16H2059/467—Detecting slip, e.g. clutch slip ratio of torque converter
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Control Of Fluid Gearings (AREA)
- Motor Power Transmission Devices (AREA)
Abstract
ABSTRACT OF THE DISCLOSURE
The present invention relates to a method for selective hydraulic driving of the wheels of a vehicle, supplementary to the main driving wheels driven by an engine through a torque converter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a variable capacity pump and a control pump driven directly by the engine, the flow and pressure of the working fluid being controlled by the controllable control pump flow, and, in superim-position of the working fluid flow control, the working fluid pressure is controlled by the pattern of a predeter-mined function selectable in dependence upon the ratio between the output r.p.m. of the engine and the output r.p.m. of the converter stages or the gearbox.
The present invention relates to a method for selective hydraulic driving of the wheels of a vehicle, supplementary to the main driving wheels driven by an engine through a torque converter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a variable capacity pump and a control pump driven directly by the engine, the flow and pressure of the working fluid being controlled by the controllable control pump flow, and, in superim-position of the working fluid flow control, the working fluid pressure is controlled by the pattern of a predeter-mined function selectable in dependence upon the ratio between the output r.p.m. of the engine and the output r.p.m. of the converter stages or the gearbox.
Description
~Z3933~
The present invention relates to a method for selective hydraulic driving of the wheels of a vehicle, supplementary to the main driving wheels driven by an engine through a torque converter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a variable capacity pump and a control pump driven directly by the engine, the flow and pressure of the working fluid being controlled by the controllable control pump flow.
As is known, grader vehicles are used for heavy earth moving operations. It is essential in this connection, when releasing solid material, working uphill, or generally working on subsoil offering little traction, for the entire weight of the machine to be used as traction weight. The front axle of a vehicle of this kind, namely a grader, carries about one third of the total weight. Now if it were possible to equip the vehicle with four wheel drive, in addition to the rear main driving wheels, i.e. to cut in the front axle, this would allow the thrust to be in-creased by up to 50%. Due to special design requirements, and this applies not only but more particularly, to graders, the additional driving of further wheels has frequently not been achievable. In the case of graders, the high structural cost of mechanical types of drive, e.g. garden shafts, may be the reason for this. The remaining operating functions, such as blade operation, must be maintained in full and care must also be taken to ensure adequate front axle ground clearance and steering lock.
One recognizes that if it is possible to produce a technical design which provides additional front wheel drive, at an acceptable cost and without restricting any of the usual functions of a grader, this should be welcome I
~3933~L
innovation in the industry.
However, matching the running speed of the main driving wheels with that of the adapted to be selectively "cut in", constitutes a problem.
Already known is a hydraulic drive for additional driving wheels, adapted to be cut in at will for heavy self propelled vehicles having their main driving wheels driven through a multi speed gearbox, the said drive come prosing a hydraulic pump and a control pump each driven I proportionally to the rum of the main vehicle engine, the said hydraulic pump making available the flow of working fluid fed to the additional driving wheels, the control pump, in the form of a fixed displacement pump, relieving the pressure of its output through a choke, the flow of working fluid for the additional wheels being controlled by the pressure upstream of the said choke, the design of the control device corresponding to the automated control, known per so, of driving mechanisms, and the hydraulic pump being in the form of a variable capacity pump which is caused to produce larger displacement volumes by the pressure upstream of the one or more chokes provided, and to produce smaller displacement volumes by the working pressure produced in the additional drive - seen for example in German patent 30 35 522.
An arrangement of the latter kind requires manual adjustment of the control pump flow with the aid of a ho-draulic valve in order to control the drive to-the additional wheels through the variable capacity pump. It is impossible in this way to achieve a stable operating condition of the additional drive wheels, especially over a wide range of rum and with the main driving wheels in various gears.
It is an aim of the invention to provide a method 123S33~.
and an apparatus for the implementation of the method for operating selectively and hydraulically driven additional wheels of a vehicle, the main driving wheels of which are driven by an engine through a torque converter or a gearbox.
The rotational velocity of the additionally driven wheels is to be matched as far as possible with that of the main driving wheels.
In the case of the method described at the begin-nine hereof, this purpose is perceived to be accomplished in that, based upon an automated control, in superimposition of the working fluid flow control, the working fluid pressure is controlled by the pattern of a predetermined function selectable in dependence upon the ratio between the output rum of the engine and the output rum of the converter stages or the gearbox. The pattern of the said function may be in several stages like a staircase curve, alternatively it may be linear or in conical sections. The pattern of the function will preferably be like that of the converter or gearbox output function.
Based upon the main driving wheels being driven by an internal combustion engine through a torque converter or a gearbox, and using an automated control for the flow of working fluid to the selectively and hydraulically driven additional wheels, a ratio former is provided, at the input to which are formed, for each converter stage or each gear speed of the main driving wheels, the output rum of the engine and of the converter stages or gearbox, the said ratio former releasing an output magnitude which cores-ponds to the ratio between input magnitudes. Also provided I is a function generator which, in dependence upon the output magnitude from the ratio former, forms from the pattern of a selectively predetermined function, a function value.
Z3g33~
Furthermore, the pressure, or the change in pressure, in the working circuit is fed to the said function generator, as a feedback, in order to complete the control circuit.
Proceeding now from a stationary operation of the working circuit, known per so, to the additional driving of other wheels, also with a known automated control, a stationary pressure has also been formed in the said circuit, for example at idling rum of the internal combustion engine which also drives the variable capacity pump and a control pump directly. In this connection, a specific control angle of two adjusting elements, working against each other with spring force, corresponds to the working fluid flow volume delivered by the variable capacity pump.
Now if the main driving wheels move, the ratio of the rum of the internal combustion engine, and of the torque con-venter or gearbox output, is formed in the ratio former and, in dependence upon this magnitude, a function value is formed in the function generator, corresponding to the selectively predetermined function. The value of the pros-sure in the working circuit is compared with this function value in the function generator. A positive deviation of the pressure in the working circuit, in relation to the function value formed, causes the variable capacity pump to alter the control angle to produce a smaller volume of working fluid. Should no positive deviation appear, the function generator will have no effect upon the variable capacity pump. If it is assumed that, because of the in-creased rum of the internal combustion engine, an in-creased pressure, as compared with the idling rum con-I diction, is fully formed, then a stable operating condition is obtained. Here again, however, the control has no effect upon the function generator until the pressure of the working 1~3933~
circuit is transferred thereto, following the increase in the rum of the internal combustion engine.
A further change in the output magnitude from the ratio former, with the same selectively predetermined function, then forms another function value in the function generator and, after comparison with the actual pressure in the working circuit, this leads, through a control de-aviation, to adjustment of the control angle of the variable capacity pump. Basically it is assumed, in this connection, that the known automated control, in dependence upon the rum of the internal combustion engine, will cause the variable capacity pump to produce, in the working circuit, a specific volume of fluid, thus establishing a corresponding operating pressure, and that this will then be altered in the sense of a speed regulation.
The selectively predetermined function, formed by the function generator in dependency upon the output magnitude from the ratio former, may utilize hydraulic elements. Thus, for example, for the purpose of producing a step-like function in the manner of a staircase curve, to provide a plurality of parallel, individually controlled limiting valves may be used, the respective excess pressure flow from which causes the variable capacity pump to adjust the control angle to produce a smaller flow of working fluid, thus decreasing the pressure thereof.
In the case of a comparable design using electronic elements know per so, the output magnitude from the ratio former, which may also comprise an electronic signal and which corresponds to the ratio of the measured rum may be fed to an electronic function generator which depicts a selected function and which compares the value f (p), corresponding to the operating pressure of the working ~23933~
circuit, with the function value actually determined.
The electronic output signal from the function generator may be fed, through hydraulic adjusting elements, to the variable capacity pump, in order to alter the control angle thereof.
A diagrammatical example of embodiment of the invention is explained hereinafter in conjunction with the drawing attached hereto, wherein:
Figure 1 shows the basic hydraulic circuitry lo for operation of the method according to the invention and the arrangements for the implementation thereof;
Figure 2 shows how a function generator may be designed with hydraulic elements to provide a selectable function.
Thus the embodiment is based upon a known pro-pollution mechanism and a known automated control for selective supplementary driving of addition wheels.
In Figure 1, engine 1, preferably an internal combustion engine, drives the main driving wheels 4 of a vehicle through a torque converter 2 and converter stages 3 thereof. Variable capacity pump 5 and control pump 6 are also driven directly by engine l, through a shaft.
These two elements of an automated control operate in a closed hydraulic working circuit which feeds wheel motors 7, 8, thus causing additionally driven wheels 9, lo to rotate. Hydraulic clutches are provided between the wheel motors and the wheels. Pressure limiting valves 13, 14 ; are provided for wheel motors 7 and 8.
The automated control also comprises, in its control circuit for adjusting the control angle increasing element 15 and decreasing element 16 of the variable capacity pump, a fixed choke 17, a variable choke 18, a pressure ~3933~
limiting valve 19 and 4/3-way valve 20. The pressure relief valve 21 limits the control pressure in the control circuit to an adjustable fixed value. The same flow of fluid from control pump 6 supplies the working circuit with fluid through one-way valves 22 and 23. Clutches 11 and 12 can be actuated by solenoid valve 24 only when the control circuit is pressurized, and this also applies to the supple-Monterey driving wheels.
Now this so far known arrangement is driven in such a manner that, in superimposition of the working fluid flow control, the working fluid pressure is controlled by the pattern of a selectively predetermined function in dependence upon the ratio between the output rum of the engine and the output rum of the converter stages or the gearbox.
To this end, a ratio former 25 is provided, to the input 26, 27 of which are fed the engine and converter output rum as measured at measuring points 28, 29, and the output magnitude 30 of the said ratio former corresponds to the ratio of the input magnitudes to each other. Also provided is a function generator 31 which forms, from the supplied output magnitude 30 of the ratio former 25, and from the pattern of a selectively predetermined function, a function value. Also fed to function generator 31, as a feedback, through lines 32, 34, is a magnitude f (p) corresponding to the pressure of the working circuit.
A positive deviation of the pressure in the working circuit, in relation to the function value formed, is fed to variable capacity pump 5, for the purpose of adjusting the control angle thereof to produce a smaller volume of working fluid, through output line 34, 4/3-way valve 20 and decreasing element 16.
I.
1~9331 In order to complete the picture, it is pointed out that 4/3-way valve 20 performs the additional function of determining the direction of travel according to its position which is set magnetically. 4/2-way value 35, which controls the pressure values fed to the function generator from the working circuit, also cuts in dependence upon the direction of travel.
Switch 36, which may be seen to form a unit with function generator 31, provides the signal to actuate sol-end valve 24.
Figure 2 illustrates an example of embodiment for the representation of a function after the manner of a staircase curve with the aid of hydraulic elements.
Corresponding technical arrangements bear the same reference numerals.
A pressure, fed through line 32 from the working circuit, is applied, with the 4/3-way hydraulic valve, which is also controlled magnetically, in the setting shown, to limiting valve 38 and, in the event of a positive pressure deviation from the set pressure, is fed, in a control deviation, through output line 34, to variable capacity pump 5. The remaining settings of 4/3 hydraulic valve 37 carry the pressure in line 32 to further limiting valves 39 or 40, which are adjusted to other pressure values.
In this connection, the pressure stages of limiting valve 38 and additional limiting valves 39 and 40, will be set progressively, e.g. 250, 150 and 100 bars. This produces, at choke 41, a control pressure in excess of the feed pros-sure hitherto obtained.
As already indicated herein before, selectable functions may also be obtained by means of electronic elements known per so. Moreover, a corresponding control lZ3933~ .
deviation may be converted, as an electronic output signal, through hydraulic adjusting elements, into the release of a signal to the variable capacity pump.
The present invention relates to a method for selective hydraulic driving of the wheels of a vehicle, supplementary to the main driving wheels driven by an engine through a torque converter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a variable capacity pump and a control pump driven directly by the engine, the flow and pressure of the working fluid being controlled by the controllable control pump flow.
As is known, grader vehicles are used for heavy earth moving operations. It is essential in this connection, when releasing solid material, working uphill, or generally working on subsoil offering little traction, for the entire weight of the machine to be used as traction weight. The front axle of a vehicle of this kind, namely a grader, carries about one third of the total weight. Now if it were possible to equip the vehicle with four wheel drive, in addition to the rear main driving wheels, i.e. to cut in the front axle, this would allow the thrust to be in-creased by up to 50%. Due to special design requirements, and this applies not only but more particularly, to graders, the additional driving of further wheels has frequently not been achievable. In the case of graders, the high structural cost of mechanical types of drive, e.g. garden shafts, may be the reason for this. The remaining operating functions, such as blade operation, must be maintained in full and care must also be taken to ensure adequate front axle ground clearance and steering lock.
One recognizes that if it is possible to produce a technical design which provides additional front wheel drive, at an acceptable cost and without restricting any of the usual functions of a grader, this should be welcome I
~3933~L
innovation in the industry.
However, matching the running speed of the main driving wheels with that of the adapted to be selectively "cut in", constitutes a problem.
Already known is a hydraulic drive for additional driving wheels, adapted to be cut in at will for heavy self propelled vehicles having their main driving wheels driven through a multi speed gearbox, the said drive come prosing a hydraulic pump and a control pump each driven I proportionally to the rum of the main vehicle engine, the said hydraulic pump making available the flow of working fluid fed to the additional driving wheels, the control pump, in the form of a fixed displacement pump, relieving the pressure of its output through a choke, the flow of working fluid for the additional wheels being controlled by the pressure upstream of the said choke, the design of the control device corresponding to the automated control, known per so, of driving mechanisms, and the hydraulic pump being in the form of a variable capacity pump which is caused to produce larger displacement volumes by the pressure upstream of the one or more chokes provided, and to produce smaller displacement volumes by the working pressure produced in the additional drive - seen for example in German patent 30 35 522.
An arrangement of the latter kind requires manual adjustment of the control pump flow with the aid of a ho-draulic valve in order to control the drive to-the additional wheels through the variable capacity pump. It is impossible in this way to achieve a stable operating condition of the additional drive wheels, especially over a wide range of rum and with the main driving wheels in various gears.
It is an aim of the invention to provide a method 123S33~.
and an apparatus for the implementation of the method for operating selectively and hydraulically driven additional wheels of a vehicle, the main driving wheels of which are driven by an engine through a torque converter or a gearbox.
The rotational velocity of the additionally driven wheels is to be matched as far as possible with that of the main driving wheels.
In the case of the method described at the begin-nine hereof, this purpose is perceived to be accomplished in that, based upon an automated control, in superimposition of the working fluid flow control, the working fluid pressure is controlled by the pattern of a predetermined function selectable in dependence upon the ratio between the output rum of the engine and the output rum of the converter stages or the gearbox. The pattern of the said function may be in several stages like a staircase curve, alternatively it may be linear or in conical sections. The pattern of the function will preferably be like that of the converter or gearbox output function.
Based upon the main driving wheels being driven by an internal combustion engine through a torque converter or a gearbox, and using an automated control for the flow of working fluid to the selectively and hydraulically driven additional wheels, a ratio former is provided, at the input to which are formed, for each converter stage or each gear speed of the main driving wheels, the output rum of the engine and of the converter stages or gearbox, the said ratio former releasing an output magnitude which cores-ponds to the ratio between input magnitudes. Also provided I is a function generator which, in dependence upon the output magnitude from the ratio former, forms from the pattern of a selectively predetermined function, a function value.
Z3g33~
Furthermore, the pressure, or the change in pressure, in the working circuit is fed to the said function generator, as a feedback, in order to complete the control circuit.
Proceeding now from a stationary operation of the working circuit, known per so, to the additional driving of other wheels, also with a known automated control, a stationary pressure has also been formed in the said circuit, for example at idling rum of the internal combustion engine which also drives the variable capacity pump and a control pump directly. In this connection, a specific control angle of two adjusting elements, working against each other with spring force, corresponds to the working fluid flow volume delivered by the variable capacity pump.
Now if the main driving wheels move, the ratio of the rum of the internal combustion engine, and of the torque con-venter or gearbox output, is formed in the ratio former and, in dependence upon this magnitude, a function value is formed in the function generator, corresponding to the selectively predetermined function. The value of the pros-sure in the working circuit is compared with this function value in the function generator. A positive deviation of the pressure in the working circuit, in relation to the function value formed, causes the variable capacity pump to alter the control angle to produce a smaller volume of working fluid. Should no positive deviation appear, the function generator will have no effect upon the variable capacity pump. If it is assumed that, because of the in-creased rum of the internal combustion engine, an in-creased pressure, as compared with the idling rum con-I diction, is fully formed, then a stable operating condition is obtained. Here again, however, the control has no effect upon the function generator until the pressure of the working 1~3933~
circuit is transferred thereto, following the increase in the rum of the internal combustion engine.
A further change in the output magnitude from the ratio former, with the same selectively predetermined function, then forms another function value in the function generator and, after comparison with the actual pressure in the working circuit, this leads, through a control de-aviation, to adjustment of the control angle of the variable capacity pump. Basically it is assumed, in this connection, that the known automated control, in dependence upon the rum of the internal combustion engine, will cause the variable capacity pump to produce, in the working circuit, a specific volume of fluid, thus establishing a corresponding operating pressure, and that this will then be altered in the sense of a speed regulation.
The selectively predetermined function, formed by the function generator in dependency upon the output magnitude from the ratio former, may utilize hydraulic elements. Thus, for example, for the purpose of producing a step-like function in the manner of a staircase curve, to provide a plurality of parallel, individually controlled limiting valves may be used, the respective excess pressure flow from which causes the variable capacity pump to adjust the control angle to produce a smaller flow of working fluid, thus decreasing the pressure thereof.
In the case of a comparable design using electronic elements know per so, the output magnitude from the ratio former, which may also comprise an electronic signal and which corresponds to the ratio of the measured rum may be fed to an electronic function generator which depicts a selected function and which compares the value f (p), corresponding to the operating pressure of the working ~23933~
circuit, with the function value actually determined.
The electronic output signal from the function generator may be fed, through hydraulic adjusting elements, to the variable capacity pump, in order to alter the control angle thereof.
A diagrammatical example of embodiment of the invention is explained hereinafter in conjunction with the drawing attached hereto, wherein:
Figure 1 shows the basic hydraulic circuitry lo for operation of the method according to the invention and the arrangements for the implementation thereof;
Figure 2 shows how a function generator may be designed with hydraulic elements to provide a selectable function.
Thus the embodiment is based upon a known pro-pollution mechanism and a known automated control for selective supplementary driving of addition wheels.
In Figure 1, engine 1, preferably an internal combustion engine, drives the main driving wheels 4 of a vehicle through a torque converter 2 and converter stages 3 thereof. Variable capacity pump 5 and control pump 6 are also driven directly by engine l, through a shaft.
These two elements of an automated control operate in a closed hydraulic working circuit which feeds wheel motors 7, 8, thus causing additionally driven wheels 9, lo to rotate. Hydraulic clutches are provided between the wheel motors and the wheels. Pressure limiting valves 13, 14 ; are provided for wheel motors 7 and 8.
The automated control also comprises, in its control circuit for adjusting the control angle increasing element 15 and decreasing element 16 of the variable capacity pump, a fixed choke 17, a variable choke 18, a pressure ~3933~
limiting valve 19 and 4/3-way valve 20. The pressure relief valve 21 limits the control pressure in the control circuit to an adjustable fixed value. The same flow of fluid from control pump 6 supplies the working circuit with fluid through one-way valves 22 and 23. Clutches 11 and 12 can be actuated by solenoid valve 24 only when the control circuit is pressurized, and this also applies to the supple-Monterey driving wheels.
Now this so far known arrangement is driven in such a manner that, in superimposition of the working fluid flow control, the working fluid pressure is controlled by the pattern of a selectively predetermined function in dependence upon the ratio between the output rum of the engine and the output rum of the converter stages or the gearbox.
To this end, a ratio former 25 is provided, to the input 26, 27 of which are fed the engine and converter output rum as measured at measuring points 28, 29, and the output magnitude 30 of the said ratio former corresponds to the ratio of the input magnitudes to each other. Also provided is a function generator 31 which forms, from the supplied output magnitude 30 of the ratio former 25, and from the pattern of a selectively predetermined function, a function value. Also fed to function generator 31, as a feedback, through lines 32, 34, is a magnitude f (p) corresponding to the pressure of the working circuit.
A positive deviation of the pressure in the working circuit, in relation to the function value formed, is fed to variable capacity pump 5, for the purpose of adjusting the control angle thereof to produce a smaller volume of working fluid, through output line 34, 4/3-way valve 20 and decreasing element 16.
I.
1~9331 In order to complete the picture, it is pointed out that 4/3-way valve 20 performs the additional function of determining the direction of travel according to its position which is set magnetically. 4/2-way value 35, which controls the pressure values fed to the function generator from the working circuit, also cuts in dependence upon the direction of travel.
Switch 36, which may be seen to form a unit with function generator 31, provides the signal to actuate sol-end valve 24.
Figure 2 illustrates an example of embodiment for the representation of a function after the manner of a staircase curve with the aid of hydraulic elements.
Corresponding technical arrangements bear the same reference numerals.
A pressure, fed through line 32 from the working circuit, is applied, with the 4/3-way hydraulic valve, which is also controlled magnetically, in the setting shown, to limiting valve 38 and, in the event of a positive pressure deviation from the set pressure, is fed, in a control deviation, through output line 34, to variable capacity pump 5. The remaining settings of 4/3 hydraulic valve 37 carry the pressure in line 32 to further limiting valves 39 or 40, which are adjusted to other pressure values.
In this connection, the pressure stages of limiting valve 38 and additional limiting valves 39 and 40, will be set progressively, e.g. 250, 150 and 100 bars. This produces, at choke 41, a control pressure in excess of the feed pros-sure hitherto obtained.
As already indicated herein before, selectable functions may also be obtained by means of electronic elements known per so. Moreover, a corresponding control lZ3933~ .
deviation may be converted, as an electronic output signal, through hydraulic adjusting elements, into the release of a signal to the variable capacity pump.
Claims (13)
1. A method for selective hydraulic driving of the wheels of a vehicle, comprising main driving wheels and sup-plementary wheels driven by an engine through a torque conver-ter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a control pump driven directly by the engine, the flow and pressure of a working fluid being con-trolled by the controllable control pump flow, characterized in that, in superimposition of the working fluid flow con-trol, the working fluid pressure is controlled by the pattern of a predetermined function selectable in dependence upon the ratio between the output r.p.m. of the engine and the output r.p.m. of the converter stages or the gearbox.
2. A method according to claim 1, characterized in that the selectively predetermined function comprises a pat-tern in several stages resembling a staircase curve.
3. A method according to claim 1, characterized in that the selectively predetermined function comprises a linear pattern.
4. A method according to claim 1, characterized in that the selectively predetermined function comprises a pat-tern of conical sections.
5. A method according to claim 1, characterized in that the selectively predetermined function is the same as the converter or gearbox output function.
6. An arrangement for a method for selective hydraulic driving of the wheels of a vehicle, comprising main driving wheels and supplementary wheels driven by an engine through a torque converter or a gearbox, by automated control of a closed hydraulic operating circuit, with wheel motors fed from a variable capacity pump, and a control pump driven directly by the engine, the flow and pressure of a working fluid being controlled by the controllable control pump flow, characterized in that, in superimposition of the working fluid flow control, the working fluid pressure is controlled by the pattern of a predetermined function selectable in dependence upon the ratio between the output r.p.m. of the engine and the output r.p.m. of the converter stages or the gearbox, characterized in that in the arrangement a ratio former is provided, to the input of which are fed, for each converter stage or gear speed of the main driving wheels, the engine and converter stage r.p.m. or magnitudes represent native thereof, the output magnitude representing the ratio of the input magnitudes to each other.
7. An arrangement according to claim 6, characterized in that a function generator is provided which generates, from the supplied output magnitude of the ratio former, and from the pattern of a selectively predetermined function, a function value.
8. An arrangement according to claim 7, characterized in that also fed to the function generator, as a feedback, is a magnitude corresponding to the pressure of the working circuit.
9. An arrangement according to claim 8, characterized in that a positive deviation of the pressure of the working circuit, in relation to the function value formed, is fed to the variable capacity pump, for the purpose of adjusting the control angle thereof to produce a smaller volume of working fluid.
10. An arrangement according to claim 9, characterized in that the function generator comprises hydraulic elements.
11. An arrangement according to claim 10, characterized in that the function generator comprises a plurality of limiting valves controlled as a function of the output magni-tude of the ratio former, the relevant excess pressure flow thereof being fed to the variable capacity pump for the pur-pose of adjusting the control angle thereof to produce a smaller volume of working fluid and thus to reduce the pressure thereof.
12. An arrangement according to claim 9, characterized in that the function generator comprises electronic elements, the control deviation being fed to the variable capacity pump through hydraulic adjusting elements.
13. An arrangement according to claim 6, characterized in that the wheel motors are connected in parallel.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| DEP3331651.1 | 1983-09-02 | ||
| DE19833331651 DE3331651C1 (en) | 1983-09-02 | 1983-09-02 | Method for the selectable supplementary hydraulic drive of wheels on a vehicle |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| CA1239331A true CA1239331A (en) | 1988-07-19 |
Family
ID=6208051
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| CA000462389A Expired CA1239331A (en) | 1983-09-02 | 1984-09-04 | Method and apparatus for selective supplementary hydraulic driving of the wheels of a vehicle |
Country Status (3)
| Country | Link |
|---|---|
| JP (1) | JPS6071334A (en) |
| CA (1) | CA1239331A (en) |
| DE (1) | DE3331651C1 (en) |
Families Citing this family (6)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| FI76632C (en) * | 1987-03-12 | 1988-11-10 | Parikkalan Kone Ja Laitehuolto | Power transmission, its control and use in trailers |
| DE3842405A1 (en) * | 1988-12-16 | 1990-06-28 | Orenstein & Koppel Ag | METHOD FOR ADDITIONAL HYDRAULIC DRIVE OF WHEELS ON A VEHICLE |
| DE3925703A1 (en) * | 1989-08-03 | 1991-02-14 | Krupp Industrietech | HYDROSTATIC DRIVE |
| DE10115797B4 (en) | 2001-03-30 | 2015-04-09 | Joseph Vögele AG | Method for controlling a self-propelled construction machine and self-propelled construction machine |
| DE102011013769A1 (en) | 2011-03-12 | 2012-09-13 | Robert Bosch Gmbh | Method for starting a vehicle with hydrostatic auxiliary drive and vehicle with hydrostatic auxiliary drive |
| FR3031785A1 (en) * | 2015-01-19 | 2016-07-22 | Renault Sa | DRIVE SYSTEM FOR A MOTOR VEHICLE |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPS5212997A (en) * | 1975-07-22 | 1977-01-31 | Japan Tobacco Inc | Improving aroma and taste of tobaccos |
| US4186816A (en) * | 1978-05-30 | 1980-02-05 | Deere & Company | Supplementary hydrostatic drive electronic control |
| DE3035522C2 (en) * | 1980-09-19 | 1983-03-24 | Zahnradfabrik Friedrichshafen Ag, 7990 Friedrichshafen | Hydrostatic drive for connectable additional drive wheels of self-propelled heavy machinery |
-
1983
- 1983-09-02 DE DE19833331651 patent/DE3331651C1/en not_active Expired
-
1984
- 1984-08-31 JP JP18090184A patent/JPS6071334A/en active Pending
- 1984-09-04 CA CA000462389A patent/CA1239331A/en not_active Expired
Also Published As
| Publication number | Publication date |
|---|---|
| DE3331651C1 (en) | 1985-05-02 |
| JPS6071334A (en) | 1985-04-23 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| MKEX | Expiry |