WO2013071041A2 - Electro-hydraulic steering system for a mobile application - Google Patents
Electro-hydraulic steering system for a mobile application Download PDFInfo
- Publication number
- WO2013071041A2 WO2013071041A2 PCT/US2012/064352 US2012064352W WO2013071041A2 WO 2013071041 A2 WO2013071041 A2 WO 2013071041A2 US 2012064352 W US2012064352 W US 2012064352W WO 2013071041 A2 WO2013071041 A2 WO 2013071041A2
- Authority
- WO
- WIPO (PCT)
- Prior art keywords
- vehicle
- steering
- directional valve
- capacity
- pump
- Prior art date
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Classifications
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/07—Supply of pressurised fluid for steering also supplying other consumers ; control thereof
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B62—LAND VEHICLES FOR TRAVELLING OTHERWISE THAN ON RAILS
- B62D—MOTOR VEHICLES; TRAILERS
- B62D5/00—Power-assisted or power-driven steering
- B62D5/06—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle
- B62D5/065—Power-assisted or power-driven steering fluid, i.e. using a pressurised fluid for most or all the force required for steering a vehicle characterised by specially adapted means for varying pressurised fluid supply based on need, e.g. on-demand, variable assist
Definitions
- the vehicle further includes an electric controlled directional valve, and wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
- FIG. 5 shows another schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
- FIG. 7 shows a method of controlling a hydraulic steering system.
- the position of a steering device may be sensed by, for example a sensor.
Landscapes
- Engineering & Computer Science (AREA)
- Chemical & Material Sciences (AREA)
- Combustion & Propulsion (AREA)
- Transportation (AREA)
- Mechanical Engineering (AREA)
- Steering Control In Accordance With Driving Conditions (AREA)
- Power Steering Mechanism (AREA)
Abstract
A vehicle steering system including a steering device, a position sensor that senses the position of the steering device, and an electronic control unit in operative communication with the position sensor and configured to control the capacity of a variable capacity pump based on output of the sensor is described herein. The variable capacity pump may be a variable displacement pump and the system may also include an electric displacement control adapted to control displacement of the variable displacement pump. The electronic control unit may be configured to determine a rate of change of the position of the steering device, and generate a capacity command signal for controlling the capacity of the variable capacity pump based on the determined rate of change.
Description
ELECTRO-HYDRAULIC STEERING SYSTEM FOR A MOBILE APPLICATION
Related Applications
This application claims the benefit of U.S. Provisional Application No.
61/557,466 filed November 9, 201 1 , which is hereby incorporated herein by reference.
Field of Invention
The present invention relates generally to electro-hydraulic systems for vehicles, and more particularly to an electro-hydraulic system for operating a power steering system.
Background
Mobile hydraulic systems that include hydraulic steering often rely on a variable capacity pump to provide hydraulic power to both the steering system and other hydraulic accessories. The variable capacity pump is typically controlled by pressure signals. Therefore, in known systems, steering units used in mobile applications (steering units, e.g.) are purely hydromechanical devices, suitable for interfacing with a pump controlled by pressure signals.
Summary of Invention
The use of a variable capacity pump with electric capacity control (electric displacement control in the case of a variable displacement pump, for example) may provide distinct advantages in response, stability, efficiency, and
productivity to the overall hydraulic system that equips a machine. However, the interaction between such a pump and any steering actuators may present difficulties and safety concerns. Therefore, also described herein are proposals for management of steering circuits using electric controlled variable capacity pumps.
According to one aspect of the invention, a vehicle steering system includes a steering device; a position sensor that senses the position of the steering device; and an electronic control unit in operative communication with
the position sensor and configured to control the capacity of a variable capacity pump based on output of the sensor, whereby the capacity of the pump is varied as a function of the output of the sensor.
Optionally, the variable capacity pump is a variable displacement pump and the system further includes an electric displacement control adapted to control displacement of the variable displacement pump.
Optionally, the vehicle steering system further includes a variable-speed motor; and an electric motor control adapted to control a speed of the variable capacity pump.
Optionally, the electronic control unit is configured to determine a rate of change of the position of the steering device, and generate a capacity command signal for controlling the capacity of the variable capacity pump based on the determined rate of change.
Optionally, the vehicle steering system further includes an orbital steering unit operatively couple to the steering device.
Optionally, the vehicle steering system further includes an electric controlled directional valve, and wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
Optionally, the vehicle steering system further includes: an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve, wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor and vehicle speed.
Optionally, the vehicle steering system further includes: an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve, wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
Optionally, hydraulic flow capacity through the orbital unit is small relative to hydraulic flow capacity through the directional valve.
Optionally, the steering device is a steering wheel.
Optionally, the steering device is a joystick.
Optionally, the vehicle steering system further includes a steering actuator.
According to another aspect of the invention, a vehicle includes a vehicle body; a steering device; a position sensor that senses the position of the steering device; an actuator mounted to the body, the movement of the actuator effects a steering function of the vehicle; a variable capacity pump for supplying hydraulic fluid to the actuator at a required capacity as a function of the sensor output; and an electronic control unit in operative communication with the position sensor and configured to control capacity of the variable capacity pump based on output of the sensor, whereby the capacity of the pump is varied as a function of the output of the sensor.
Optionally, the variable capacity pump is a variable displacement pump, and the vehicle further includes an electric displacement control adapted to control displacement of a variable displacement pump
Optionally, the electronic control unit is configured to determine a rate of change of the position of the steering device, and generate a capacity command signal for controlling the capacity of the variable capacity pump based on the determined rate of change.
Optionally, the vehicle further includes an orbital steering unit operatively couple to the steering device.
Optionally, the vehicle further includes an electric controlled directional valve, and wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
Optionally, the vehicle further includes an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve, wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor and vehicle speed.
Optionally, the vehicle further includes an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve, wherein the electronic control unit is configured to generate a directional valve
control signal for controlling the directional valve based on an output of the position sensor.
Optionally, hydraulic flow capacity through the orbital unit is small relative to hydraulic flow capacity through the directional valve.
Optionally, the steering device is a steering wheel.
Optionally, steering device is a joystick.
Optionally, the vehicle further includes one or more hydraulic accessories powered by the variable displacement pump.
Optionally, the vehicle further includes a priority compensator.
Optionally, the priority compensator is hydraulically controlled.
Optionally, the priority compensator is electrically controlled.
According to another aspect of the invention, a method of providing hydraulic power to a steering system includes: sensing a position of a steering device; and generating a displacement command signal for controlling capacity of a variable capacity pump based on the sensing.
Optionally, the method further includes: determining a rate of change of the position of the steering device based on the sensing, and wherein the generating comprises generating the displacement command signal for controlling the displacement of the variable displacement pump based on the rate of change.
Optionally, the method further includes pumping hydraulic fluid with the variable capacity pump to a steering actuator.
Optionally, the method further includes pumping hydraulic fluid with the variable capacity pump to one or more hydraulic accessories.
Optionally, the method further includes generating an accessory valve signal for controlling the state of an electrically controlled accessory valve.
Optionally, the method further includes generating a steering valve signal for controlling the state of an electrically controlled steering valve.
According to another aspect of the invention, a non-transitory computer readable medium having stored thereon a computer program comprising computer executable instructions is configured to execute the method.
According to another aspect of the invention, a computer program embodied on a non-transitory computer readable medium includes computer executable instructions configured to execute the method.
The foregoing and other features of the invention are hereinafter described in greater detail with reference to the accompanying drawings.
Brief Description of the Drawings
FIG. 1 shows a schematic overview of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 2 shows a schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 3 shows another schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 4 shows another schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 5 shows another schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 6 shows another schematic of a hydraulic system including an electronic control unit operatively coupled to a variable capacity pump.
FIG. 7 shows a method of controlling a hydraulic steering system.
Detailed Description
Even though layouts of hydraulic circuits in accordance with the present invention may vary and may use different hardware, the control concepts utilized therein may be the same in all layouts (for example, as shown in FIG 1 ): an operator of a vehicle may operate a steering device 20 (for example, turns the steering wheel), which is connected to a position sensor 30 which may sense the position of the steering device 20 (for example, the angular displacement of a steering wheel). The sensor may alternatively or additionally sense the rate of change of position (and/or acceleration, and/or jerk, etc.), or this value may be determined by an electronic control unit 40. Thus, the steering position and/or its derivative(s) are read by the ECU and used to generate a control signal commanding a variable capacity pump 80. If the variable capacity pump is a
variable-displacement pump, the signal generated by the control function 50 may be a pump displacement command 60 to determine the displacement of the variable-displacement pump 80. Likewise, the control function may generate one or more valve section commands 70 for controlling one or more valve sections, if present, by, for example, controlling the current to one or more solenoids.
Note that the variable capacity of the pump 80 is usually achieved through a variable displacement pump, but it can also be achieved through other means, including, for example, a fixed displacement pump driven by a variable speed motor, in which the motor speed is controlled by an output signal from the electronic control unit 40. Further, although any steering device may be used, in this disclosure, reference may be made specifically to a steering wheel to be used with a rotary position sensor. It will be understood, however, that any suitable steering device may be used with an appropriate position sensor, and reference to a specific embodiment should not be read as limiting, but rather as illustrating a preferred embodiment.
Turning now to FIG. 2, a hydraulic system is illustrated. The system includes a hydraulic reservoir 102, a hydraulic pump 180 with variable capacity in which the variable displacement is electrically controlled (e.g. using solenoids or the like), one or more hydraulic valves 190, 192, 194 where at least one spool section 190 is dedicated to the control of one or more steering actuators 191 . In the system depicted in FIG. 2, the steering sections are also electrically controlled, meaning, for example, that the spool position may be proportional to an electric signal. Other valve sections or spools 192, 194 are dedicated to the control of one or more other accessory (rotary or linear) actuators 193, 195 on the vehicle. A steering device 120 (e.g. a steering wheel, one or more levers, joystick, or the like) is equipped with a steering position sensor 130. An electronic control unit 140 may receive different input signals, including an input signal from the sensor 130, and may generate an output signal to control the capacity of the pump 180 and control the valves 190, 192, 194. The control of the capacity of the variable capacity pump 180 may be effectuated through, for example, an intermediary electric displacement controller 185 in the case of a variable displacement pump.
Turning now to Fig. 3, an exemplary embodiment of the hydraulic system is shown at 200. The hydraulic system 200 is substantially the same as the above-referenced hydraulic system 100, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the hydraulic system 100. In addition, the foregoing description of the hydraulic system 100 is equally applicable to the hydraulic system 200 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the hydraulic systems may be substituted for one another or used in conjunction with one another where applicable.
In the hydraulic system 200, here the hydraulic valve(s) 290, 292, 294 are equipped with a priority element 275 that may guarantee that the steering flow matches the desired value. The excess flow may be diverted to the remaining function actuators 293, 295. The priority element can be controlled by means of a hydraulic signal or by means of an electric signal. Priority to the steering actuator(s) 291 may also be achieved via sectional compensators, in which the steering section has a priority-style compensator.
Fig. 4 shows another system 300 layout. The system 300 includes a hydraulic reservoir 302; a steering interface 320 (e.g., a steering wheel); a rotary position sensor 330 reading the angular position of the steering shaft 322; a hydraulic pump 380 with variable capacity in which the displacement is electrically controlled (e.g., using solenoids) by, for example, an electric displacement control 385, which may receive control signals from an electronic control unit 340, which reads different input signals and provides output current to that and possibly other control solenoids; and one or more steering actuators 391 (represented as cylinders).
An orbital steering valve 390 may be used to control fluid flow to the steering actuator 391 : this valve includes a rotary spool, and a pump-motor unit which acts as feedback device. The rotary spool typically has at least 6 connecting ports: pump (P), reservoir (T), pump-motor supply (X), pump-motor return (Y), steering supply (A), steering return (B). The rotary spool may be directly or indirectly linked to the steering wheel shaft. The pump-motor unit may be linked to the spool sleeve, so that the flow of oil causes the rotation of the
pump-motor and a rotation of the sleeve by an angle which is proportional to the amount of oil displaced by the pump-motor. When an operator turns the steering wheel, the spool opens a flow path from the main pump to the steering actuators, passing through the pump-motor unit. The rotation of the pump-motor unit causes the sleeve to gradually close the oil passage. As a result, the amount of oil displaced to the steering actuator is proportional to the rotation of the steering wheel.
Turning now to Fig. 5, an exemplary embodiment of the hydraulic system is shown at 400. The hydraulic system 400 is substantially the same as the above-referenced hydraulic system 300, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the hydraulic system 300. In addition, the foregoing description of the hydraulic system 300 is equally applicable to the hydraulic system 400 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the hydraulic systems may be substituted for one another or used in conjunction with one another where applicable.
Instead of an orbital steering unit, the system 400 employs a directional valve 490 controlling the flow from the pump 480 to the steering actuators 491 . This valve 490 connects the pump delivery (P) and the reservoir (T) to the two ports of the steering actuators (A, B). The valve 490 may be equipped with electric control. In other words, the position of the valve 490 may be electrically controlled, for example, with solenoids, and it may be proportional to a current or a voltage signal generated by the electronic control unit 440 as described above. This configuration further allows for vehicle steering to be modified by other factors. For example, the steering rate may be dependent on vehicle speed in addition to other factors. For example, the steering system may be more sensitive at lower speeds for increased steering control and less sensitive at high speeds for increased safety. Thus, the electronic control unit may receive input signals from additional sensors, such as, for example, a vehicle speedometer or from other control units that compute such, or other, useful values.
If tactile feedback is desired with this system, a separate, haptic-feedback system may be used.
Turning now to Fig. 6, an exemplary embodiment of the hydraulic system is shown at 500. The hydraulic system 500 is substantially the same as the above-referenced hydraulic system 400, and consequently the same reference numerals but indexed by 100 are used to denote structures corresponding to similar structures in the hydraulic system 400. In addition, the foregoing description of the hydraulic system 400 is equally applicable to the hydraulic system 500 except as noted below. Moreover, it will be appreciated upon reading and understanding the specification that aspects of the hydraulic systems may be substituted for one another or used in conjunction with one another where applicable.
In the system 500, an orbital steering unit 590 is provided in parallel to a directional vale 598. This combination allows the orbital unit 590 to provide tactile feedback and provide a back-up steering system in case some component of the directional valve 598 fails. Additionally, the directional valve 598 provides power-assistance to the operator, reducing the effort needed to steer a vehicle. This system also allows for steering that is dependent on multiple variables such as vehicle-speed-dependent steering.
Optionally, the flow of hydraulic fluid through the orbital unit 590 is small relative to the portion of the flow provided through the directional valve 598.
Turning now to FIG. 6, a method 600 of controlling hydraulic power in a steering system is shown.
At block 610, the position of a steering device may be sensed by, for example a sensor.
At block 620, the rate of change of the position of the steering device may be determined. This determination may be made, for example, by a sensor, by a separate conditioning circuit, or by an electronic control unit.
At block 630, an electronic control unit may generate a capacity control signal. The control signal may be based on the determined rate of change.
At block 640, the electronic control unit may further generate a steering valve signal for implementations using an electronically controlled directional valve for controlling hydraulic flow to a steering actuator.
At block 650, the electronic control unit may further generate an
accessory valve signal for implementations using one or more electronically
controlled directional valves for controlling hydraulic flow to one or more accessory actuators.
At block 660, the variable capacity pump may pump hydraulic fluid to the one or more steering actuators.
Finally, at block 670, the variable capacity pump may pump hydraulic fluid to one or more accessory actuators.
Although the illustrated methods illustrate a specific order of executing functional logic blocks, the order of execution of the blocks may be changed relative to the order shown and/or may be implemented in a state-driven or an object-oriented manner. Also, two or more blocks shown in succession may be executed concurrently or with partial concurrence. Certain blocks also may be omitted. Further, although certain blocks have been described as being executed or performed by specific functional components of the hydraulic systems 100, 200, 300, 400, and 500, these blocks need not be performed by these components or may be performed by one or more other components. It is understood that all such variations are within the scope of the present invention.
Blocks of the method 600 may be embodied as a set of executable instructions (e.g., referred to in the art as code, programs, or software) that are respectively resident in and executed by the electronic control unit 40, 140, 240, 340, 440, 540. The method 600 may be one or more programs that are stored on respective non-transitory computer readable mediums, such as one or more memory devices (e.g., an electronic memory, a magnetic memory, or an optical memory).
Although the invention has been shown and described with respect to a certain embodiment or embodiments, it is obvious that equivalent alterations and modifications will occur to others skilled in the art upon the reading and understanding of this specification and the annexed drawings. In particular regard to the various functions performed by the above described elements (components, assemblies, devices, compositions, etc.), the terms (including a reference to a "means") used to describe such elements are intended to correspond, unless otherwise indicated, to any element which performs the specified function of the described element (i.e., that is functionally equivalent), even though not structurally equivalent to the disclosed structure which performs
the function in the herein illustrated exemplary embodiment or embodiments of the invention. In addition, while a particular feature of the invention may have been described above with respect to only one or more of several illustrated embodiments, such feature may be combined with one or more other features of the other embodiments, as may be desired and advantageous for any given or particular application.
Claims
1 . A vehicle steering system comprising:
a steering device;
a position sensor that senses the position of the steering device; and an electronic control unit in operative communication with the position sensor and configured to control the capacity of a variable capacity pump based on output of the sensor, whereby the capacity of the pump is varied as a function of the output of the sensor.
2. The vehicle steering system of claim 1 , wherein the variable capacity pump is a variable displacement pump, the system further comprising: an electric displacement control adapted to control displacement of the variable displacement pump.
3. The vehicle steering system of any preceding claim further comprising:
a variable-speed motor; and
an electric motor control adapted to control a speed of the variable capacity pump.
4. The vehicle steering system of any preceding claim, wherein the electronic control unit is configured to determine a rate of change of the position of the steering device, and generate a capacity command signal for controlling the capacity of the variable capacity pump based on the determined rate of change.
5. The vehicle steering system of any preceding claim, further comprising an orbital steering unit operatively couple to the steering device.
6. The vehicle steering system of any one of the preceding claims further comprising an electric controlled directional valve, and wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
7. The vehicle steering system of any one of the preceding claims further comprising:
an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve,
wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor and vehicle speed.
8. The vehicle steering system of any one of the preceding claims further comprising:
an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve,
wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
9. The vehicle steering system of any preceding claim, wherein hydraulic flow capacity through the orbital unit is small relative to hydraulic flow capacity through the directional valve.
10. The vehicle steering system of any one of the preceding claims, wherein the steering device is a steering wheel.
1 1 . The vehicle steering system of any one of the preceding claims, wherein the steering device is a joystick.
12. The vehicle steering system of any one of the preceding claims, further comprising a steering actuator.
13. A vehicle comprising:
a vehicle body;
a steering device;
a position sensor that senses the position of the steering device;
an actuator mounted to the body, the movement of the actuator effects a steering function of the vehicle;
a variable capacity pump for supplying hydraulic fluid to the actuator at a required capacity as a function of the sensor output; and
an electronic control unit in operative communication with the position sensor and configured to control capacity of the variable capacity pump based on output of the sensor, whereby the capacity of the pump is varied as a function of the output of the sensor.
14. The vehicle of any preceding claim, wherein the variable capacity pump is a variable displacement pump, the vehicle further comprising:
an electric displacement control adapted to control displacement of a variable displacement pump.
15. The vehicle of any preceding claim, wherein the electronic control unit is configured to determine a rate of change of the position of the steering device, and generate a capacity command signal for controlling the capacity of the variable capacity pump based on the determined rate of change.
16. The vehicle of any preceding claim, further comprising an orbital steering unit operatively couple to the steering device.
17. The vehicle of any one of the preceding claims further comprising an electric controlled directional valve, and wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
18. The vehicle of any one of the preceding claims further comprising: an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve,
wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor and vehicle speed.
19. The vehicle of any one of the preceding claims further comprising: an orbital steering unit operatively couple to the steering device; and an electric controlled directional valve,
wherein the electronic control unit is configured to generate a directional valve control signal for controlling the directional valve based on an output of the position sensor.
20. The vehicle of any preceding claim, wherein hydraulic flow capacity through the orbital unit is small relative to hydraulic flow capacity through the directional valve.
21 . The vehicle of any one of the preceding claims, wherein the steering device is a steering wheel.
22. The vehicle of any one of the preceding claims, wherein the steering device is a joystick.
23. The vehicle of any one of the preceding claims, further comprising one or more hydraulic accessories powered by the variable displacement pump.
24. The vehicle of any one of the preceding claims, further comprising a priority compensator.
25. The vehicle of any one of the preceding claims, wherein the priority compensator is hydraulically controlled.
26. The vehicle of any one of the preceding claims, wherein the priority compensator is electrically controlled.
27. A method of providing hydraulic power to a steering system, the method comprising:
sensing a position of a steering device; and
generating a displacement command signal for controlling capacity of a variable capacity pump based on the sensing.
28. The method of any preceding claim, further comprising:
determining a rate of change of the position of the steering device based on the sensing, and
wherein the generating comprises generating the displacement command signal for controlling the displacement of the variable displacement pump based on the rate of change.
29. The method of any preceding claim, further comprising:
pumping hydraulic fluid with the variable capacity pump to a steering actuator.
30. The method of any preceding claim, further comprising:
pumping hydraulic fluid with the variable capacity pump to one or more hydraulic accessories.
31 . The method of any preceding claim, further comprising:
generating an accessory valve signal for controlling the state of an electrically controlled accessory valve.
32. The method of any preceding claim, further comprising:
generating a steering valve signal for controlling the state of an electrically controlled steering valve.
33. A non-transitory computer readable medium having stored thereon a computer program comprising computer executable instructions configured to execute the method according to any one of claims 27-32.
34. A computer program embodied on a non-transitory computer readable medium comprising computer executable instructions configured to execute the method according to any one of claims 27-32.
Applications Claiming Priority (2)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US201161557466P | 2011-11-09 | 2011-11-09 | |
| US61/557,466 | 2011-11-09 |
Publications (2)
| Publication Number | Publication Date |
|---|---|
| WO2013071041A2 true WO2013071041A2 (en) | 2013-05-16 |
| WO2013071041A3 WO2013071041A3 (en) | 2013-07-04 |
Family
ID=47430044
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| PCT/US2012/064352 WO2013071041A2 (en) | 2011-11-09 | 2012-11-09 | Electro-hydraulic steering system for a mobile application |
Country Status (1)
| Country | Link |
|---|---|
| WO (1) | WO2013071041A2 (en) |
Family Cites Families (7)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| JPH11235982A (en) * | 1997-12-16 | 1999-08-31 | Toyota Autom Loom Works Ltd | Hydraulic system for fork-lift truck |
| US6069460A (en) * | 1998-06-01 | 2000-05-30 | Ford Global Technologies, Inc. | Method for controlling an electro-hydraulic power assist steering system |
| DE19919393A1 (en) * | 1999-04-28 | 2000-11-02 | Steinbock Boss Gmbh Foerdertec | Auxiliary power steering system for fitting to a stacker truck has a hydraulic steering actuator to engage one or more steerable wheels, a steering pump supplying hydraulic liquid and a hydraulic control unit to control its flow. |
| JP3487223B2 (en) * | 1999-07-07 | 2004-01-13 | 株式会社豊田自動織機 | Power steering system |
| DE102004028826A1 (en) * | 2004-06-15 | 2006-01-05 | Zf Lenksysteme Gmbh | Servo-assisted steering system of a motor vehicle |
| JP4800118B2 (en) * | 2006-06-05 | 2011-10-26 | 株式会社小松製作所 | Vehicle steering system |
| DE102010043679B4 (en) * | 2010-11-10 | 2024-02-01 | Knorr-Bremse Systeme für Nutzfahrzeuge GmbH | Operating method for a hydraulic power steering system and hydraulic power steering system |
-
2012
- 2012-11-09 WO PCT/US2012/064352 patent/WO2013071041A2/en active Application Filing
Non-Patent Citations (1)
| Title |
|---|
| None |
Also Published As
| Publication number | Publication date |
|---|---|
| WO2013071041A3 (en) | 2013-07-04 |
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