GB2395768A - Hydraulic vehicle speed limiting system - Google Patents
Hydraulic vehicle speed limiting system Download PDFInfo
- Publication number
- GB2395768A GB2395768A GB0227633A GB0227633A GB2395768A GB 2395768 A GB2395768 A GB 2395768A GB 0227633 A GB0227633 A GB 0227633A GB 0227633 A GB0227633 A GB 0227633A GB 2395768 A GB2395768 A GB 2395768A
- Authority
- GB
- United Kingdom
- Prior art keywords
- pump
- traveling
- speed
- pressure
- vehicle speed
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Granted
Links
- 230000005540 biological transmission Effects 0.000 abstract description 19
- 239000012530 fluid Substances 0.000 description 29
- 238000001514 detection method Methods 0.000 description 10
- 230000007935 neutral effect Effects 0.000 description 3
- 238000000034 method Methods 0.000 description 2
Classifications
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- 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
- F16H61/47—Automatic regulation in accordance with output requirements for achieving a target output speed
-
- 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
-
- 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
-
- B—PERFORMING OPERATIONS; TRANSPORTING
- B60—VEHICLES IN GENERAL
- B60W—CONJOINT CONTROL OF VEHICLE SUB-UNITS OF DIFFERENT TYPE OR DIFFERENT FUNCTION; CONTROL SYSTEMS SPECIALLY ADAPTED FOR HYBRID VEHICLES; ROAD VEHICLE DRIVE CONTROL SYSTEMS FOR PURPOSES NOT RELATED TO THE CONTROL OF A PARTICULAR SUB-UNIT
- B60W2720/00—Output or target parameters relating to overall vehicle dynamics
- B60W2720/10—Longitudinal speed
-
- 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
- F16H59/68—Inputs being a function of gearing status
- F16H2059/6838—Sensing gearing status of hydrostatic transmissions
- F16H2059/6861—Sensing gearing status of hydrostatic transmissions the pressures, e.g. high, low or differential pressures
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- 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
- F16H47/00—Combinations of mechanical gearing with fluid clutches or fluid gearing
- F16H47/02—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type
- F16H47/04—Combinations of mechanical gearing with fluid clutches or fluid gearing the fluid gearing being of the volumetric type the mechanical gearing being of the type with members having orbital motion
-
- 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
- F16H59/44—Inputs being a function of speed dependent on machine speed of the machine, e.g. the vehicle
Landscapes
- Engineering & Computer Science (AREA)
- General Engineering & Computer Science (AREA)
- Mechanical Engineering (AREA)
- Control Of Fluid Gearings (AREA)
- Operation Control Of Excavators (AREA)
Abstract
A speed limiting system for a vehicle with a hydraulic transmission comprising pump 12 driving motor 13 through discharge 41, forward 46F and reverse 46R circuits and a pilot operated reversing valve 21. The system has pump capacity control means 12C controlling the pump swash plate12a via control cylinder 12CC subject to control valve 12CLS which exposes the cylinder to either tank 12A or discharge pressure 12B according to a control valve balance of discharge pressure LS2 plus a spring 12CP and motor load pressure LS1 plus solenoid reaction 12CS. A speed detecting pump 17, motor 18 set plus sensor 31 supply controller 30 with vehicle speed and when a set speed is exceeded the controller changes the solenoid reaction to alter the pressure balance to reduce pump capacity. The set speed may be changed by replacing removable module 39 in the controller.
Description
1 2395768
VEHICLE SPEED LIMITING SYSTEM OF HYDRAULIC TRAVELING VEHICLE
FIELD OF THE INVENTION
The present invention relates to a vehicle speed limiting system of a working vehicle, in particular a hydraulic traveling vehicle.
BACKGROUND OF THE INVENTION
Conventionally, in a hydraulic traveling vehicle which is traveled by driving a variable capacity type traveling hydraulic motor on the basis of a pressure fluid of a traveling hydraulic pump driven by an engine, a maximum vehicle speed is limited by a capacity of the traveling hydraulic motor. Further, the maximum vehicle speed is different in correspondence to a nation in which the hydraulic traveling vehicle travels, and in the case of exporting the hydraulic traveling vehicle to a nation having a different maximum vehicle speed, the vehicles on which the traveling hydraulic motors having different capacities are exported to.the respective nations.
However, in the case of preparing various kinds of traveling hydraulic motors having the different capacities for the hydraulic traveling vehicles in correspondence to the maximum vehicle speeds in the respective nations, the kind of the traveling hydraulic motors is increased. Further, the kind of associated parts such as pipes and the like for making the vehicle correspond to the traveling hydraulic
motor is increased, and a man hour for control is increased.
Further, in the case that the specification is changed before
shipping, it is necessary to recompose the traveling hydraulic motor, so that an extra assembling man hour is generated. SUMMARY OF THE INVENTION
The present invention is made by taking the problems mentioned above into consideration, and an object of the present invention is to provide a vehicle speed limiting system which can limit a vehicle speed by a simple structure, in a hydraulic traveling vehicle.
In order to achieve the object mentioned above, in accordance with a first aspect of the present invention, there is provided a vehicle speed limiting system of a hydraulic traveling vehicle provided with a traveling hydraulic motor and a variable capacity type traveling hydraulic pump, comprises a pump capacity control means for controlling a capacity of the variable capacity type traveling hydraulic pump so that a pressure difference between a load pressure of the traveling hydraulic motor and a discharge pressure of the variable capacity type traveling hydraulic pump becomes a load sensing set pressure (hereinafter, refer to an LS set pressure), a vehicle speed detecting means of the hydraulic traveling vehicle, and a controller changing the LS set pressure in the case that a vehicle speed detected by the vehicle speed detecting means
is over a set value so as to reduce a capacity of the variable capacity type traveling hydraulic pump.
In accordance with the first aspect of the present invention, since the LS set pressure is changed in the case that the vehicle speed is over the set value, and then the capacity of the variable capacity type traveling hydraulic pump is reduced, the vehicle speed limiting system can be achieved by a simple structure.
In accordance with a second aspect of the present invention, there is provided a vehicle speed limiting system of the hydraulic traveling vehicle as described in the first aspect, wherein the controller is provided with an LS set pressure setting means for setting the LS set pressure, and the setting means is replaceable by another setting means which is selected from a plurality of other LS set pressure setting means.
In accordance with the second aspect, since the LS set pressure setting means is provided with the replaceable controller, the limit vehicle speed can be simply changed only by replacing the setting means by the LS set pressure setting means selected from a plurality of other setting means. BRIEF DESCRIPTION OF THE DRAWINGS
Fig. 1 is a system schematic view of a vehicle speed limiting system of a hydraulic traveling vehicle in accordance with the present invention.
J
BEST MODE FOR CARRYING OUT THE INVENTION
A description will be given in detail of a vehicle
speed limiting system of a hydraulic traveling vehicle in accordance with the present invention with reference to Fig. 1. A traveling pump 12 is connected to an engine 11, and the traveling pump 12 is driven by the engine 11 so as to discharge a pressure fluid. The pressure fluid discharged from the traveling pump 12 is fed to a traveling motor 13 via a hydraulic swivel joint 15 through a travel control valve 21.
The traveling motor 13 is connected to an input shaft of a transmission 14, and drives the transmission 14.
A travel speed detecting pump 17 is provided in the transmission 14, and is structured such as to rotate in proportion to a rotation of an output shaft of the transmission 14. The pressure fluid discharged from the travel speed detecting pump 17 is fed to a travel speed detecting motor 18 via the hydraulic swivel joint 15. The traveling pump 12 is a variable capacity hydraulic pump, and has a pump capacity control means 12C. Further, the traveling motor 13 is a variable capacity hydraulic motor, and has a motor capacity control means 13C.
In this case, a working vehicle (not shown) is provided with a lower traveling body (not shown) and an upper revolving body (not shown). A working machine (not shown) is provided in the upper revolving body, and the hydraulic
swivel joint 15 is provided in a connection portion between the lower traveling body and the upper revolving body. The engine 11 is provided in the upper revolving body (not shown), the transmission 14 is provided in the lower traveling body (not shown), and a controller 30 is provided in the upper revolving body (not shown).
The transmission 14 is connected to a speed change valve 16 corresponding to a speed change control means via the hydraulic swivel join 15. The speed change valve 16 feeds the pressure fluid from a mission pump 19 to a first speed clutch 14F or a second speed clutch 14S in the transmission 14 via the hydraulic swivel joint 15. The speed change valve 16 is a twoposition switching valve having a simple structure and a low cost, and switches between an illustrated first speed position 16A and a second speed position 16B on the basis of a speed change signal from the controller 30.
The transmission 14 has a planetary gear mechanism, and applies or releases the pressure to or from the first speed clutch 14F for a low speed or the second speed clutch 14S for a high speed on the basis of a pressure signal from the speed change valve 16 so as to engage or disengage the clutch, thereby setting a speed stage. That is, the first speed clutch 14F and the second speed clutch 14S are of a type applying the pressure fluid so as to engage the clutch and releasing the pressure fluid so as to disengage the clutch.
Further, the transmission 14 has two speed stages J
comprising a first speed stage and a second speed stage. In the case of setting the transmission 14 to the first speed, the speed change valve 16 is set to the first speed position 16A, the first speed clutch is engaged by applying the pressure fluid from the speed change valve 16 to the first speed clutch 14F, and the second speed clutch 14S is disengaged by releasing the pressure fluid of the second speed clutch 14S. In the case of setting the transmission 14 to the second speed, the speed change valve 16 is set to the second speed position 16B, the second speed clutch is engaged by applying the pressure fluid from the speed change valve 16 to the second speed clutch 14S, and the first speed clutch 14F is disengaged by releasing the pressure fluid of the first speed clutch 14F.
A vehicle speed detection gear 35 for generating a vehicle speed signal is provided in the output shaft of the vehicle speed detecting motor 18, and is rotated by the vehicle speed detecting motor 18. For example, a predetermined number of teeth, slits or concavity and convexity are formed on an outer periphery of the vehicle speed detection gear 35. A vehicle speed detection sensor 31 is provided close to the outer periphery of the vehicle speed detection gear 35, and generates a pulse which is generated, for example, at a time when a predetermined number of teeth pass through a signal detection portion of the vehicle speed detection sensor 31, as an electric signal.
The vehicle speed detection sensor 31 corresponding to J
a vehicle speed detecting means is connected to the controller 30, and transmits a vehicle speed signal as an electric signal to the controller 30. The controller 30 arithmetically processes the vehicle speed signal so as to calculate the vehicle speed.
The travel control valve 21 is switched from an illustrated neutral position N to a forward moving position F or a rearward moving position R. and controls an orientation of the pressure fluid discharged from the traveling pump 12 so as to feed the pressure fluid to the traveling motor 13.
The travel control valve 21 receives a travel pilot pressure corresponding to a pilot pressure from a forward and backward movement switching valve 22 by a forward movement side pressure receiving portion 21F or a rearward movement side pressure receiving portion 21R of the travel control valve 21, thereby being switched from the neutral position N to the forward moving position F or the rearward moving position R. The forward and backward movement switching valve 22 is switched to an illustrated forward moving position FK on the basis of the forward moving signal from the controller 30, and is switched to a rearward moving position RK on the basis of the rearward moving signal.
An accelerator pedal 23A operates a travel pilot pressure valve 23 by being pedaled down and generates the travel pilot pressure. The travel pilot pressure corresponding to a pedaling amount detecting means of the accelerator pedal 23A changes in correspondence to a pedaling
l amount of the accelerator pedal 23A, and is structured such as to be increased in accordance with a predetermined rate as the pedaling amount of the accelerator pedal 23A is increased.
A travel load pressure sensor 33 corresponding to a load pressure detecting means is provided in a circuit between the traveling pump 12 and the travel control valve 21.
The travel load pressure sensor 33 transmits a detected travel load pressure signal to the controller 30.
A forward travel pressure sensor 36 is provided in a circuit between the forward and rearward movement switching valve 22 of the travel control valve 21 and the forward movement side pressure receiving portion 21F of the travel control valve 21. A rearward travel pressure sensor 37 is provided in a circuit between the forward and rearward movement switching valve 22 and the rearward movement side pressure receiving portion 21R of the travel control valve 21.
An internal switch of the forward travel pressure sensor 36 is turned on by the travel pilot pressure, and the forward travel pressure sensor 36 transmits the forward travel signal to the controller 30. An internal switch of the rearward travel pressure sensor 37 is turned on by the travel pilot pressure, and the rearward travel pressure sensor 37 transmits the rearward travel signal to the controller 30.
The travel control valve 21 s connected to the traveling motor 13 via the hydraulic swivel joint 15, by a forward movement side circuit 46F and a rearward movement side circuit 46R. A circuit 47F branched from the forward
movement side circuit 46F disposed between the travel control valve 21 and the hydraulic swivel joint 15, and a circuit 47R branched from the rearward movement side circuit 46R are connected via a shuttle valve 42. An output circuit LSM of the shuttle valve 42 is connected to the pump capacity control means 12C. The pressure fluid in any higher one of the forward movement side circuit 46F and the rearward movement side circuit 46R is output as a motor load pressure LS1 of the traveling motor 13 from the shuttle valve 42, and is input to the pump capacity control means 12C through the output circuit LSM.
A discharge circuit 41 of the traveling pump 12 is connected to the travel control valve 21. A pump pressure detecting circuit LSP branched from the discharge circuit 41 is connected to the pump capacity control means 12C. A pump discharge pressure LS2 in the discharge circuit 41 of the traveling pump 12 is input to the pump capacity control means 12C. The pump capacity control means 12C is connected to the controller 30. The pump capacity control means 12C controls the capacity of the traveling pump 12 so that a pressure difference ALS(= LS2 - LS1) between the pump discharge pressure LS2 of the traveling pump 12 and the motor load pressure LS1 of the traveling motor 13 becomes a predetermined LS set pressure in correspondence to the pump capacity signal transmitted from the controller 30. An LS electromagnetic proportional valve 12CLS is provided in the
pump capacity control means 12C, and is structured such as to set the set pressure in correspondence to the signal from the controller 30.
An electromagnetic coil 12CS and a spring 12CP are provided in both sides of the LS electromagnetic proportional valve 12CLS. The electromagnetic coil 12CS gives a reaction force to a spool (not shown) of the LS electromagnetic proportional valve 12CLS in correspondence to the signal from the controller 30. The spool in the LS electromagnetic proportional valve 12CLS moves to a position at which a combined force of a reaction force applied by the electromagnetic coil 12CS and a pressing force due to the motor load pressure LS1 of the traveling motor 13, is balanced with a combined force of a force due to the discharge pressure LS2 of the traveling pump 12 and a force applied by the spring 12CP. In correspondence to an opening amount of the spool, the LS electromagnetic proportional valve 12CLS feeds the pressure fluid applied from the discharge circuit 41 of the traveling pump 12 to the pump capacity control cylinder 12CC. That is, the pump capacity control means 12C forms a load sensing means for detecting the pressure difference ALS(= LS2 - LS1) between the pump discharge pressure LS2 of the traveling pump 12 and the motor load pressure LS1 of the traveling motor 13. The set pressure of the spool of the electromagnetic proportional valve 12CLS balanced in accordance with the pressure difference ALS is set to an LS set pressure.
When the force applied to the motor load pressure LS1 of the traveling motor 13 is increased, the LS electromagnetic proportional valve 12CLS becomes at an illustrated position 12A, the pressure fluid in the pump capacity control cylinder 12CC is drained to an oil tank 25, a swash plate 12a of the traveling pump 12 is inclined in an illustrated max direction, and the capacity of the traveling pump 12 is increased. On the contrary, if the force due to the pump discharge pressure LS2 of the traveling pump 12 becomes large, the LS electromagnetic proportional valve 12CLS is positioned at a position 12B, and the pressure fluid enters- into the pump capacity control cylinder 12CC so as to incline the awash plate 12a of the traveling pump 12 in an illustrated min direction, and the capacity of the traveling pump 12 is reduced.
In this case, if the reaction force of the spool applied by the electromagnetic coil 12CS of the LS electromagnetic proportional valve 12CLS is made small, the combined force of the force due to the pump discharge pressure LS2 of the traveling pump 12 and the force applied by the spring 12CP becomes larger than the combined force of the reaction force applied by the electromagnetic coil 12CS and the pressing force due to the motor load pressure LS1 of the traveling motor 13. Accordingly, the LS electromagnetic proportional valve 12CLS moves to the position 12B.
Therefore, the pressure fluid is input to the pump capacity control cylinder 12CC, it is possible to incline the swash
plate 12a of the traveling pump 12 in the min direction, and it is possible to reduce the capacity of the traveling pump 12. Accordingly, the structure is made such that the swash plate 12a of the traveling pump 12 can be inclined in the min direction and the capacity of the traveling pump 12 can be reduced, by changing the LS set pressure corresponding to the set pressure for the pump capacity control means 12C as the load sensing means.
A forward and rearward movement switch 34 is connected to the controller 30, and transmits a forward movement command signal or a rearward movement command signal to the controller 30.
The controller 30 calculates as a load due to a traveling resistance whether or not the pressure of the pressure fluid discharged by the traveling pump 12 is over a predetermined value, when the controller 30 receives a traveling load pressure signal which a traveling load pressure sensor 33 in a circuit between the traveling pump 12 and the travel control valve 21 detects.
The controller 30 arithmetically processes a vehicle speed signal corresponding to an electric signal detected by the vehicle speed detection sensor 31 so as to calculate the vehicle speed. In the case that the vehicle speed is over a predetermined speed, for example, 50km/h, the controller 30 transmits a pump capacity reduction signal for reducing the capacity of the traveling pump 12 to the pump capacity control means 12C. When the electromagnetic proportional -
valve 12CLS of the pump capacity control means 12C receives the pump capacity reduction signal, the electromagnetic proportional valve 12CLS reduces the reaction force of the spool in the electromagnetic proportional valve 12CLS applied by the electromagnetic coil 12CS. Then, since the combined force of the force due to the pump discharge pressure LS2 of the traveling pump 12 and the force applied by the spring 12CP becomes greater than the combined force of the reaction force applied by the electromagnetic coil 12CS and the pressing force due to the motor load pressure LS1 of the traveling motor 13 as mentioned above, the LS electromagnetic proportional valve 12CLS moves to the position 12B, and reduces the capacity of the traveling pump 12.
Further, the controller 30 is provided with an LS set pressure setting adapter 39 corresponding to an LS set pressure setting means capable of setting the LS set pressure.
The LS set pressure setting adapter 39 is structured detachable so as to be replaced from an exterior portion with respect to the controller 30 by a connector(not shown).
Plural kinds of maximum vehicle speeds can be set by setting the LS set pressure to plural kinds, for example, by replacing by an adapter for maximum vehicle speed 50km/h, an adapter for maximum vehicle speed 60km/h, an adapter for maximum vehicle speed 70km/h, or the like. For example, in the case of mounting the LS set pressure setting adapter 39 corresponding to the adapter for maximum vehicle speed 50km/h, the vehicle speed is calculated by arithmetically processing
the vehicle speed signal corresponding to the electric signal detected by the vehicle speed detection sensor 31, and in the case that the vehicle speed is over 50km/h, the capacity of the traveling pump 12 is reduced in the manner mentioned above. Next, a description will be given of an operation of
the vehicle speed limiting system in accordance with the present invention.
When an operator switches the forward and rearward movement switch 34 to the forward movement side, the forward and rearward movement switching valve 22 is set to the forward moving position FK, and when pedaling down the accelerator pedal 23A, the travel pilot pressure is applied to the forward movement side pressure receiving portion 21F of the travel control valve 21, and is switched from the neutral position N to the forward moving position F. The forward travel pressure sensor 36 is turned on an internal switch by the travel pilot pressure, and transmits the forward travel signal to the controller 30.
The controller 30 first switches the speed change valve 16 to the first speed position 16A on the basis of the forward movement command signal of the forward and rearward movement switch 34 and a speed stage signal (for example, a second speed) set by a speed stage lever (not shown), next engages the first speed clutch 14F and disengages the second speed clutch 14S, thereby changing the transmission 14 to the
forward first speed.
The travel control valve 21 transmits the pressure fluid discharged from the traveling pump 12 to a forward movement side port 13F of the traveling motor 13 via the hydraulic swivel joint 15. The traveling motor 13 rotates in the forward moving direction so as to drive the transmission 14, and the working vehicle travels forward.
When the vehicle speed is increased, and the vehicle speed signal from the vehicle speed detection sensor 31 is over the maximum vehicle speed, for example, 50km/h, the controller 30 transmits a pump capacity reduction signal for reducing the capacity of the traveling pump 12 to the pump capacity control means 12C.
When the LS electromagnetic proportional valve 12CLS of the pump capacity control means 12C receives the pump capacity reduction signal, the LS electromagnetic proportional valve 12CLS makes the reaction force of the spool applied by the electromagnetic coil 12CS small.
Accordingly, since the combined force of the force due to the pump discharge pressure LS2 of the traveling pump 12 and the force applied by the spring 12CP becomes larger than the combined force of the reaction force applied by the electromagnetic coil 12CS and the pressing force due to the motor load pressure LS1 of the traveling motor 13, the LS electromagnetic proportional valve 12CLS moves to the position 12B. The pressure fluid is input to the pump capacity control cylinder 12CC, it is possible to incline the
swash plate 12a of the traveling pump 12 in the min direction, and it is possible to reduce the capacity of the traveling pump 12.
Further, when the speed of the working vehicle is reduced, and becomes equal to or less than the maximum vehicle speed, for example, the vehicle speed 50km/h, the controller 30 transmits the pump capacity signal to he pump capacity control means 12C so as to increase the capacity of the traveling pump 12.
As mentioned above, in accordance with the present invention, the vehicle speed can be limited only by transmitting the pump capacity reduction signal to the LS electromagnetic proportional valve 12CLS of the pump capacity control means 12C and making the reaction force of the spool applied by the electromagnetic coil 12CS small. Accordingly, in the structure in which the load sensing means is used for the pump capacity control means 12C of the hydraulic traveling vehicle, the existing pump capacity control means 12C may be used, it is not necessary to add a new additional part, and it is sufficient to change a control soft for the controller 30. In accordance with a simple structure mentioned above, the hydraulic traveling vehicle corresponding to the working vehicle can travel without being over the maximum speed corresponding to the limited vehicle speed. Further, it is possible to change the maximum vehicle speed only replace the LS set pressure setting adapter 39
1' corresponding to the LS set pressure setting means and also corresponding to the maximum vehicle speed setting means.
Accordingly, it is possible to easily change the maximum vehicle speed corresponding to the limited vehicle speed.
Further, the hydraulic traveling vehicle may be a vehicle having no upper revolving body, and the present invention can be applied, for example, to a wheel loader, a fork lift or the other working vehicles. In the case of applying the vehicle speed limiting system in accordance with the present invention to the vehicle provided with no upper revolving body, the hydraulic swivel joint 15 may be omitted.
-In the case, the first speed clutch 14F for low speed and the second speed clutch 14S for high speed in the transmission 14 are described as a clutch of the type in which the clutch is engaged by applying the pressure fluid and the clutch is disengaged by releasing the pressure fluid.
On the contrary, the clutch may be structured as a type in which springs for connecting the clutches are provided in the first speed clutch 14F for low speed and the second speed clutch 14S for high speed, and the clutch is engaged by releasing the pressure fluid and the clutch is disengaged by applying the pressure fluid. That is, in the case of setting the transmission 14 to the first speed, the first speed clutch is engaged by releasing the pressure fluid supplied from the speed change valve 16 to the first speed clutch 14F, and the second speed clutch 14S is disengaged by applying the pressure fluid of the second clutch INS, thereby setting the
transmission 14 to the first speed. In the case of setting the transmission 14 to the second speed, the second speed clutch is engaged by releasing the pressure fluid supplied from the speed change valve 16 to the second speed clutch 14S, and the first speed clutch 14F is disengaged by applying the pressure fluid of the first clutch 14F, thereby setting the transmission 14 to the second speed.
Claims (2)
1. A vehicle speed limiting system of a hydraulic traveling vehicle provided with a traveling hydraulic motor and a variable capacity type traveling hydraulic pump, comprising: a pump capacity control means (12C) for controlling a capacity of the variable capacity type traveling hydraulic pump so that a pressure difference between a load pressure of the traveling hydraulic motor and a discharge pressure of the variable capacity type traveling hydraulic pump becomes a load sensing set pressure (an LS set pressure); a vehicle speed detecting means of said hydraulic traveling vehicle; and a controller (30) changing said LS set pressure in the case that a vehicle speed detected by the vehicle speed detecting means is over a set value so as to reduce a capacity of said variable capacity type traveling hydraulic pump.
2. A vehicle speed limiting system of a hydraulic traveling vehicle as claimed in claim 1, wherein said controller (30) is provided with an LS set pressure setting means (39) for setting said LS set pressure, and the setting means is replaceable by another setting means which is selected from a plurality of other LS set pressure setting means.
Priority Applications (5)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0227633A GB2395768B (en) | 2002-11-27 | 2002-11-27 | Vehicle speed limiting system of hydraulic travelling vehicle |
| JP2003385170A JP2004176919A (en) | 2002-11-27 | 2003-11-14 | Speed limit system for hydraulic running vehicle |
| DE10354198A DE10354198B4 (en) | 2002-11-27 | 2003-11-20 | Speed limit system of a hydraulic vehicle |
| FR0313605A FR2847524B1 (en) | 2002-11-27 | 2003-11-20 | VEHICLE SPEED LIMITATION SYSTEM FOR HYDRAULIC MOBILE VEHICLE |
| CNB200310118054XA CN100515818C (en) | 2002-11-27 | 2003-11-24 | Speed limiting system of oil hydraulic running vehicle |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| GB0227633A GB2395768B (en) | 2002-11-27 | 2002-11-27 | Vehicle speed limiting system of hydraulic travelling vehicle |
Publications (3)
| Publication Number | Publication Date |
|---|---|
| GB0227633D0 GB0227633D0 (en) | 2003-01-08 |
| GB2395768A true GB2395768A (en) | 2004-06-02 |
| GB2395768B GB2395768B (en) | 2006-01-25 |
Family
ID=9948587
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| GB0227633A Expired - Fee Related GB2395768B (en) | 2002-11-27 | 2002-11-27 | Vehicle speed limiting system of hydraulic travelling vehicle |
Country Status (5)
| Country | Link |
|---|---|
| JP (1) | JP2004176919A (en) |
| CN (1) | CN100515818C (en) |
| DE (1) | DE10354198B4 (en) |
| FR (1) | FR2847524B1 (en) |
| GB (1) | GB2395768B (en) |
Cited By (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3492663A4 (en) * | 2017-09-29 | 2020-11-04 | Hitachi Construction Machinery Co., Ltd. | Wheel loader |
Families Citing this family (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN104495626B (en) * | 2014-12-30 | 2017-01-04 | 中联重科股份有限公司 | Crane control method, device and system and crane |
Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2231691A (en) * | 1989-05-05 | 1990-11-21 | Rexroth Mannesmann Gmbh | Control for a load-dependently operating variable displacement pump |
| US5390759A (en) * | 1992-08-10 | 1995-02-21 | Sauer Inc. | Driving mechanism for an automotive propel drive |
Family Cites Families (3)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| US4474104A (en) * | 1983-04-11 | 1984-10-02 | Double A Products Co. | Control system for variable displacement pumps and motors |
| JPH08135789A (en) * | 1994-11-09 | 1996-05-31 | Komatsu Ltd | Transmission for vehicular hydraulic drive device and control method for the transmission |
| US6381529B1 (en) * | 2001-06-07 | 2002-04-30 | Deere & Company | Control system for hydrostatic transmission |
-
2002
- 2002-11-27 GB GB0227633A patent/GB2395768B/en not_active Expired - Fee Related
-
2003
- 2003-11-14 JP JP2003385170A patent/JP2004176919A/en active Pending
- 2003-11-20 DE DE10354198A patent/DE10354198B4/en not_active Expired - Fee Related
- 2003-11-20 FR FR0313605A patent/FR2847524B1/en not_active Expired - Fee Related
- 2003-11-24 CN CNB200310118054XA patent/CN100515818C/en not_active Expired - Fee Related
Patent Citations (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| GB2231691A (en) * | 1989-05-05 | 1990-11-21 | Rexroth Mannesmann Gmbh | Control for a load-dependently operating variable displacement pump |
| US5390759A (en) * | 1992-08-10 | 1995-02-21 | Sauer Inc. | Driving mechanism for an automotive propel drive |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| EP3492663A4 (en) * | 2017-09-29 | 2020-11-04 | Hitachi Construction Machinery Co., Ltd. | Wheel loader |
| US11242672B2 (en) | 2017-09-29 | 2022-02-08 | Hitachi Construction Machinery Co., Ltd. | Wheel loader |
Also Published As
| Publication number | Publication date |
|---|---|
| GB0227633D0 (en) | 2003-01-08 |
| DE10354198A1 (en) | 2004-06-09 |
| CN1509917A (en) | 2004-07-07 |
| GB2395768B (en) | 2006-01-25 |
| FR2847524B1 (en) | 2009-03-06 |
| CN100515818C (en) | 2009-07-22 |
| DE10354198B4 (en) | 2008-09-04 |
| FR2847524A1 (en) | 2004-05-28 |
| JP2004176919A (en) | 2004-06-24 |
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Legal Events
| Date | Code | Title | Description |
|---|---|---|---|
| COOA | Change in applicant's name or ownership of the application |
Owner name: KOMATSU LTD Free format text: FORMER APPLICANT(S): KOMATSU UK LIMITED |
|
| PCNP | Patent ceased through non-payment of renewal fee |
Effective date: 20131127 |