US20130152574A1 - Working Vehicle Travel Control Apparatus - Google Patents

Working Vehicle Travel Control Apparatus Download PDF

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Publication number
US20130152574A1
US20130152574A1 US13/818,799 US201113818799A US2013152574A1 US 20130152574 A1 US20130152574 A1 US 20130152574A1 US 201113818799 A US201113818799 A US 201113818799A US 2013152574 A1 US2013152574 A1 US 2013152574A1
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United States
Prior art keywords
transmission
gear ratio
motor
transmission gear
displacement angle
Prior art date
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Abandoned
Application number
US13/818,799
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English (en)
Inventor
Yasuo Yamazaki
Shouroku Kawahara
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Hitachi Construction Machinery Co Ltd
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Hitachi Construction Machinery Co Ltd
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Filing date
Publication date
Application filed by Hitachi Construction Machinery Co Ltd filed Critical Hitachi Construction Machinery Co Ltd
Assigned to HITACHI CONSTRUCTION MACHINERY CO., LTD. reassignment HITACHI CONSTRUCTION MACHINERY CO., LTD. ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: KAWAHARA, SHOUROKU, YAMAZAKI, YASUO
Publication of US20130152574A1 publication Critical patent/US20130152574A1/en
Abandoned legal-status Critical Current

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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
    • F16H61/02—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 characterised by the signals used
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/2058—Electric or electro-mechanical or mechanical control devices of vehicle sub-units
    • E02F9/2079—Control of mechanical transmission
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F3/00—Dredgers; Soil-shifting machines
    • E02F3/04—Dredgers; Soil-shifting machines mechanically-driven
    • E02F3/28—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets
    • E02F3/283—Dredgers; Soil-shifting machines mechanically-driven with digging tools mounted on a dipper- or bucket-arm, i.e. there is either one arm or a pair of arms, e.g. dippers, buckets with a single arm pivoted directly on the chassis
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/202—Mechanical transmission, e.g. clutches, gears
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2221—Control of flow rate; Load sensing arrangements
    • E02F9/2232—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps
    • E02F9/2235—Control of flow rate; Load sensing arrangements using one or more variable displacement pumps including an electronic controller
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2253—Controlling the travelling speed of vehicles, e.g. adjusting travelling speed according to implement loads, control of hydrostatic transmission
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2289—Closed circuit
    • E—FIXED CONSTRUCTIONS
    • E02—HYDRAULIC ENGINEERING; FOUNDATIONS; SOIL SHIFTING
    • E02F—DREDGING; SOIL-SHIFTING
    • E02F9/00—Component parts of dredgers or soil-shifting machines, not restricted to one of the kinds covered by groups E02F3/00 - E02F7/00
    • E02F9/20—Drives; Control devices
    • E02F9/22—Hydraulic or pneumatic drives
    • E02F9/2278—Hydraulic circuits
    • E02F9/2296—Systems with a variable displacement pump
    • 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
    • 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
    • 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
    • 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
    • F16H61/4148—Open loop circuits
    • 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
    • F16H61/421—Motor capacity control by electro-hydraulic control means, e.g. using solenoid valves
    • 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
    • F16H61/462—Automatic regulation in accordance with output requirements for achieving a target speed ratio
    • 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
    • F16H61/70—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 specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements
    • F16H61/702—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 specially adapted for change-speed gearing in group arrangement, i.e. with separate change-speed gear trains arranged in series, e.g. range or overdrive-type gearing arrangements using electric or electrohydraulic control means

Definitions

  • the present invention relates to a travel control apparatus of a working vehicle such as a wheel loader.
  • Patent Literature 1 There is a conventionally known working vehicle travel control apparatus that includes a transmission using a clutch that can be controlled only into a state of full engagement or a state of full disengagement, in which occurrence of a shock from when the disengaged clutch is engaged again is reduced (refer to Patent Literature 1). More specifically, occurrence of a gear shift shock when the clutch is engaged again is reduced by controlling the displacement angle of a hydraulic pump and matching the number of rotation between a power upstream-side with a power downstream-side of the clutch.
  • Patent Literature 1 Japanese Laid-Open Patent Publication No. 2002-139148
  • Patent Literature 1 described above is configured to reduce a gear shift shock by matching the number of rotation between a power upstream-side with a power downstream-side of the clutch, and hence a synchronization mechanism for matching the number of rotation is required.
  • a working vehicle travel control apparatus comprising: a variable displacement hydraulic pump that is driven by an engine; a variable displacement hydraulic motor that is connected in a closed circuit to the hydraulic pump and driven upon pressure oil from the hydraulic pump; a first control unit that controls a motor displacement angle of the hydraulic motor by an electrical signal; a constant mesh transmission that includes a clutch device that includes a High clutch section that transmits power at a first transmission gear ratio and a Low clutch section that transmits power at a second transmission gear ratio, which is greater than the first transmission gear ratio, the constant mesh transmission that transmits or interrupts power from the hydraulic motor; and a second control unit that controls the first control unit so as to reduce the motor displacement angle to a predetermined value when the transmission is switched from the first transmission gear ratio to the second transmission gear ratio.
  • the predetermined value of the motor displacement angle is set to be greater than a minimum displacement angle of the hydraulic motor and a minimal motor displacement angle at which the working vehicle can be driven by the hydraulic motor.
  • the second control unit controls the first control unit so that when the transmission is switched from the first transmission gear ratio to the second transmission gear ratio, after the motor displacement angle is reduced to the predetermined value and fixed to the predetermined value for a predetermined period of time, and then the motor displacement angle is recovered.
  • a wheel loader comprising a travel control apparatus according to any one of the first to third aspect.
  • a gear shift shock can be reduced at the time of switching from High to Low.
  • FIG. 1 is a side view of a working vehicle to which the travel control apparatus according to an embodiment of the present invention is applied.
  • FIG. 2 is a diagram showing the outline structure of the travel control apparatus according to the present embodiment.
  • FIG. 3 is a diagram of the configuration of a transmission.
  • FIG. 4 is a diagram showing a shift change process from High to Low.
  • FIG. 5( a ) and FIG. 5( b ) are diagrams showing a traveling performance diagram of a working vehicle to which the travel control apparatus according to the present embodiment is applied and a comparison example, respectively.
  • a working vehicle travel control apparatus according to an embodiment of the present invention will now be explained with reference to FIG. 1 to FIG. 5 .
  • FIG. 1 is a side view of a wheel loader that is an example of a working vehicle to which the travel control apparatus according to the present embodiment is applied.
  • a wheel loader 100 is constituted with a front body 110 that includes an arm 111 , a bucket 112 , tires 113 , etc., and a rear body 120 that includes a driver's cabin 121 , an engine bay 122 , tires 123 , etc.
  • the arm 111 vertically rotates (moves up and down) on actuation of an arm cylinder 114 and the bucket 112 vertically rotates (dumps or crowds) on actuation of a bucket cylinder 115 .
  • the front body 110 and the rear body 120 are rotatably connected with each other through a center pin 101 , so that expansion and contraction of a steering cylinder (not shown in the figure) causes the front body 110 to turn right and left with respect to the rear body 120 .
  • FIG. 2 is a diagram showing the outline structure of the travel control apparatus according to the present embodiment.
  • a variable displacement hydraulic pump 2 which is driven by an engine 1 , and a variable displacement hydraulic motor 3 are connected in a closed circuit through a pair of main lines LA and LB and thus a so-called HST circuit is configured.
  • Pressure oil from a charge pump 5 which is driven by the engine 1 is led to a displacement cylinder 8 through a forward/reverse switching valve 6 .
  • the forward/reverse switching valve 6 is operated on a signal from a controller 10 .
  • pressure oil from the charge pump 5 acts upon both valve chambers 8 a and 8 b of the displacement cylinder 8 through a restrictor 7 and the forward/reverse switching valve 6 .
  • pressure acts equally upon the oil chambers 8 a and 8 b and a piston 8 c is in the neutral position. For this reason, a displacement qp of the hydraulic pump 2 becomes 0 and a pump discharge rate Q is 0 .
  • Rotation of the hydraulic motor 3 is shifted by a transmission 130 , the shifted rotation is transmitted to the tires 113 and 123 through a propeller shaft and axle, and thus the vehicle travels.
  • the transmission 130 can be switched between two speeds, Low and High, by an operation with a High/Low selection switch 23 .
  • An accelerator pedal 9 is provided with an operation amount detector 9 a, which detects an operation amount of the accelerator pedal 9 , and a signal from the operation amount detector 9 a is input to the controller 10 .
  • the controller 10 outputs a rotational speed control signal to an engine control unit 1 a and the engine rotational speed is controlled according to the signal from the operation amount detector 9 a.
  • Pressure oil from the charge pump 5 passing through the restrictor 7 and a check valve in an overload relief valve 13 , is led to the main lines LA and LB and replenished into the HST circuit. Downstream-side pressure of the restrictor 7 is restricted by a charge relief valve 12 and the maximum pressure at the main lines LA and LB is restricted by the overload relief valve 13 .
  • a displacement qm (motor displacement angle) of the hydraulic motor 3 is controlled by a regulator 14 .
  • the regulator 14 which is an electrical regulator that includes a solenoid valve, a proportional solenoid valve, etc., is driven by control current that is output from the controller 10 through signal lines 14 a and 14 b so as to drive a displacement control lever 140 and change the motor displacement angle qm.
  • a motor displacement control unit is provided with a stopper 15 .
  • the displacement control lever 140 comes to a stop against the stopper 15 so as to mechanically restrict the minimum value of the motor displacement angle qm to a predetermined value qmin.
  • the controller 10 is configured to include an arithmetic processing unit that has a CPU, a ROM, a RAM, other peripheral circuits, etc.
  • a signal from a pressure detector 21 which detects pressure (travel load pressure Pt) at the main lines LA and LB, a signal from a vehicle speed sensor 17 , which detects the vehicle speed, a signal from the High/Low selection switch 23 , and a signal from a quick shift switch 24 are input to the controller 10 .
  • the quick shift switch 24 is a switch that is provided, separately from the High/Low selection switch 23 , on a grip of a cargo handling lever (not illustrated) so as to switch between High and Low.
  • the controller 10 controls the motor displacement angle qm in accordance with a travel load pressure Pt (PID control). With an increase in the travel load pressure Pt, the motor displacement angle qm gradually increases from the minimum value qmin to the maximum value qmax.
  • the rotational speed of the hydraulic motor 2 is expressed by pump discharge rate Q x motor displacement efficiency/motor displacement qm and the vehicle speed is proportional to the motor rotational speed. Accordingly, when the travel load pressure Pt is great and the motor displacement angle qm is great, the vehicle can travel at a low speed and high torque, and, on the other hand, when the travel load Pt is little and the motor displacement angle qm is little, the vehicle can travel at a high speed and low torque.
  • FIG. 3 shows the configuration of the transmission 130 .
  • the transmission 130 is a so-called constant mesh transmission.
  • the transmission 130 includes an input shaft 131 through which power from the hydraulic motor 3 is input, an output shaft 132 through which the input power is output to the axle, and a clutch device 133 that transmits or interrupts power from the input shaft 131 to the output shaft 132 .
  • the clutch device 133 is a wet multi-disk clutch that transmits or interrupts power by press-contacting or spacing a plurality of axially juxtaposed disks.
  • the clutch device 133 causes one of a high gear 134 and a low gear 135 to rotate integrally with the input shaft 131 .
  • the high gear 134 and the low gear 135 are in mesh with driven gears 136 and 137 that are coupled with the output shaft 132 , respectively.
  • driven gears 136 and 137 that are coupled with the output shaft 132 , respectively.
  • rotation of the input shaft 131 is transmitted to the output shaft 132 through the low gear 135 and the driven gear 137 .
  • the clutch device 133 includes a high clutch 133 a and the high gear 134 for transmitting power at the first transmission gear ratio and a low clutch 133 b and the low gear 135 for transmitting power at the second transmission gear ratio, which is greater than the first transmission gear ratio.
  • the high clutch 133 a and the low clutch 133 b operate upon pressure oil from a transmission control valve 138 .
  • the transmission control valve 138 is controlled by an instruction from the controller 10 .
  • the transmission control valve 138 is switched and pressure that acts upon the low clutch 133 b rises, the low clutch 133 b is gradually connected and then switched to the low state (refer to FIG. 3 ).
  • pressure that acts upon the high clutch 133 a rises due to switching of the transmission control valve 138 , the high clutch 133 a is gradually connected and then switched to the high state.
  • a High/Low switch-type transmission as mentioned above has advantages such as lower manufacturing cost and better fuel economy compared with an automatic transmission that shifts gear automatically.
  • gear shift shock occurs due to the gear ratio between the high gear 134 and the low gear 135 .
  • a threefold difference in gear ratio results in one third the vehicle speed and threefold the traction force when the transmission is shifted down from High to Low, thereby causing a great shock due to a decrease in the vehicle speed, slip of the tires due to an increase in the traction force, and the like.
  • a gear shift shock is reduced by reducing the motor displacement angle of the hydraulic motor 3 at the time of switching from High to Low.
  • the controller 10 when instructed to switch the transmission from High to Low by an operation with the High/Low selection switch 23 , the controller 10 permits gear shift if the vehicle speed is less than a gear shift limit. When instructed to switch the transmission from High to Low with the vehicle speed being equal to or greater than the gear shift limit, the controller 10 permits gear shift if the vehicle speed decreases to the gear shift limit. On the other hand, when instructed to switch the transmission from High to Low by an operation with the quick shift switch 24 , the controller 10 permits gear shift only if the High/Low selection switch 23 is operated to High and the vehicle speed is less than the gear shift limit. If the vehicle speed is equal to or greater than the gear shift limit and the quick shift switch 24 is operated, the controller 10 judges that a signal from the quick shift switch 24 is invalid.
  • the gear shift limit is set in advance to an appropriate value so as to reduce a gear shift shock at the time of switching from High to Low (10 km/h for instance). It is to be noted that the motor displacement angle is not particularly controlled when switching from Low to High.
  • FIG. 4 shows a shift change process from High to Low.
  • the horizontal axis represents time and the vertical axis represents a motor displacement instruction value.
  • a motor displacement instruction value qi is an instruction value of the motor displacement angle that is output from the controller 10 to the regulator 14 of the hydraulic motor 3 . It is assumed that the vehicle is in operation in High state and the vehicle speed is less than the gear shift limit and the motor displacement instruction value qi is qa. In a normal state other than when the gear is shifted, the motor displacement is PID-controlled based upon a circuit pressure detected by the pressure detector 21 .
  • the controller 10 If, in this state, the operator operates the High/Low selection switch 23 or the quick shift switch 24 so as to switch the transmission from High to Low at a time point t 1 , the controller 10 outputs a predetermined value qb to the regulator 14 as the motor displacement instruction value qi so as to reduce the motor displacement angle.
  • the predetermined value qb is set to a motor displacement angle equal to or greater than the minimum value qmin described above, so that a minimal amount of oil with which the vehicle can be driven by the hydraulic motor 3 can be ensured even if, for example, an electrical abnormality occurs at the regulator 14 .
  • the motor displacement instruction value qi is fixed to the predetermined value qb.
  • the controller 10 outputs at a time point t 2 to the transmission 140 an instruction to switch the transmission from High to Low.
  • the transmission control valve 138 is switched, pressure that acts upon the low clutch 133 b rises, and the low clutch 133 b is gradually connected and then switched to Low state.
  • the controller 10 After outputting the instruction to switch the transmission from High to Low at the time point t 2 , the controller 10 outputs an instruction to the regulator 14 so as to recover the motor displacement instruction value qi from the predetermined value qb to a value in accordance with the PID control during a predetermined transition time ⁇ T 2 .
  • the motor displacement instruction value qi increases with a predetermined slope during the transition time ⁇ T 2 , and, after the transition time ⁇ T 2 has elapsed, the PID control is resumed based upon the circuit pressure at that time point.
  • the predetermined value qb of the motor displacement instruction value qi is set in advance to an appropriate value that is less than 1 ⁇ 3 of the motor displacement instruction value qa, e.g., approximately 1 ⁇ 4 of qa, at the time of the instruction to switch the transmission from High to Low in view of delay in the control system and the like.
  • An appropriate value (400 msec for instance) is set in advance to the predetermined elapsed time ⁇ T 1 as a latency during which from when the motor displacement instruction value qb is output to when the motor displacement angle of the hydraulic motor 3 is switched in accordance with the instruction value qb.
  • the predetermined transition time ⁇ T 2 is set in advance to an appropriate period of time (1 sec for example) as a ramp time during which the control of the motor displacement angle is smoothly recovered to the normal PID control.
  • the predetermined value qb, the elapsed time ⁇ T 1 , and the transition time ⁇ T 2 are not limited to the examples given above and appropriate values are set in accordance with specifications of the vehicle and the like.
  • FIG. 5( a ) shows an example of traveling performance diagram of a vehicle to which the travel control apparatus according to the present embodiment is applied.
  • the gear ratio between the high gear 134 and the low gear 135 is assumed to be threefold.
  • FIG. 5( b ) shows a comparison example.
  • the horizontal axis represents the vehicle speed
  • the vertical axis represents the traction force.
  • the transmission gear is shifted from High to Low at A
  • the vehicle speed becomes 1 ⁇ 3 and the traction force becomes threefold at the moment of shift down. This causes a great shock due to a decrease in the vehicle speed and slip of tires and the like due to an increase in the traction force.
  • displacement of the hydraulic motor 3 is shifted to a small displacement side at the time of switching the transmission from High to Low.
  • the motor displacement angle By shifting the motor displacement angle to a small displacement, the vehicle speed at the time of switching to Low state becomes higher, i.e., reduction in the vehicle speed decreases becomes lower and the traction force also becomes lower. This causes gear shift shock at the time of switching from High to Low to be reduced, thereby achieving a smooth gear shift operation.
  • the travel control apparatus described above may be applied to a working vehicle other than a wheel loader, e.g., a road machine such as a tire roller and a road roller.

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  • Engineering & Computer Science (AREA)
  • General Engineering & Computer Science (AREA)
  • Mechanical Engineering (AREA)
  • Mining & Mineral Resources (AREA)
  • Civil Engineering (AREA)
  • Structural Engineering (AREA)
  • Physics & Mathematics (AREA)
  • Fluid Mechanics (AREA)
  • Control Of Transmission Device (AREA)
  • Control Of Fluid Gearings (AREA)
  • Operation Control Of Excavators (AREA)
US13/818,799 2010-08-31 2011-06-24 Working Vehicle Travel Control Apparatus Abandoned US20130152574A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2010194083A JP5301509B2 (ja) 2010-08-31 2010-08-31 作業車両の走行制御装置
JP2010-194083 2010-08-31
PCT/JP2011/064570 WO2012029389A1 (fr) 2010-08-31 2011-06-24 Appareil de commande de déplacement pour véhicule de travail

Related Parent Applications (1)

Application Number Title Priority Date Filing Date
PCT/JP2011/064570 A-371-Of-International WO2012029389A1 (fr) 2010-08-31 2011-06-24 Appareil de commande de déplacement pour véhicule de travail

Related Child Applications (1)

Application Number Title Priority Date Filing Date
US14/985,748 Continuation US20160194854A1 (en) 2010-08-31 2015-12-31 Working Vehicle Travel Control Apparatus

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Publication Number Publication Date
US20130152574A1 true US20130152574A1 (en) 2013-06-20

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US13/818,799 Abandoned US20130152574A1 (en) 2010-08-31 2011-06-24 Working Vehicle Travel Control Apparatus
US14/985,748 Abandoned US20160194854A1 (en) 2010-08-31 2015-12-31 Working Vehicle Travel Control Apparatus

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US14/985,748 Abandoned US20160194854A1 (en) 2010-08-31 2015-12-31 Working Vehicle Travel Control Apparatus

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US (2) US20130152574A1 (fr)
EP (1) EP2589836A4 (fr)
JP (1) JP5301509B2 (fr)
KR (1) KR20130124475A (fr)
CN (1) CN103026099A (fr)
WO (1) WO2012029389A1 (fr)

Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140138177A1 (en) * 2011-09-07 2014-05-22 Hitachi Construction Machinery Co., Ltd. Construction machine
CN107310384A (zh) * 2017-07-27 2017-11-03 天津工程机械研究院有限公司 一种全液压行走装载机传动系统
US11384511B2 (en) * 2019-03-29 2022-07-12 Hitachi Construction Machinery Co., Ltd. Wheeled work vehicle

Families Citing this family (12)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
JP5754397B2 (ja) 2012-03-09 2015-07-29 三菱電機株式会社 縦型トレンチｉｇｂｔの製造方法
JP6258593B2 (ja) * 2013-03-25 2018-01-10 日立建機株式会社 作業車両の自動変速装置
JP5899167B2 (ja) * 2013-08-08 2016-04-06 日立建機株式会社 作業車両の自動変速装置
US9759313B2 (en) * 2014-11-26 2017-09-12 Polaris Industries Inc. Electronic shifting of a transmission
US9746070B2 (en) 2014-11-26 2017-08-29 Polaris Industries Inc. Electronic control of a transmission
JP6438368B2 (ja) * 2015-09-18 2018-12-12 ヤンマー株式会社 作業車両
US10519627B2 (en) 2017-02-08 2019-12-31 Caterpillar Inc. Pull-slip control system for track-type tractor and track-type tractor operating method
WO2020183665A1 (fr) * 2019-03-13 2020-09-17 日立建機株式会社 Véhicule de travail de manipulation de marchandises
US11866912B2 (en) 2019-09-19 2024-01-09 Doosan Bobcat North America, Inc. Drive motor displacement control
CN110594409B (zh) * 2019-10-18 2024-03-12 三一汽车制造有限公司 柔性换挡液压系统及其控制方法与工程机械
KR20210058434A (ko) * 2019-11-14 2021-05-24 두산인프라코어 주식회사 자동 변속 장치가 구비된 건설 기계 및 변속 제어 방법
WO2022113784A1 (fr) * 2020-11-26 2022-06-02 日立建機株式会社 Machine de roulement

Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4621495A (en) * 1983-01-13 1986-11-11 Stensele Mekaniska Verkstad Ab Synchronized mechanical-hydrostatic gearbox
US20070137338A1 (en) * 2005-09-30 2007-06-21 Kubota Corporation Speed control structure and method for work vehicle
US20090259374A1 (en) * 2006-06-28 2009-10-15 Brueninghaus Hydromatik Gmbh Method of controlling a transmission ratio

Family Cites Families (13)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4766779A (en) * 1984-03-05 1988-08-30 Fabco Automotive Corporation Hydrostatic transmission assembly and method of increasing the torque and speed range thereof
IT1245204B (it) * 1991-03-15 1994-09-13 Fritz Carl Anton Hurth Cambio di velocita' a motori idrostatici particolarmente per macchine movimento terra
DE4223846C2 (de) * 1992-07-20 1996-03-28 Hydromatik Gmbh Getriebeeinheit zur Anordnung zwischen einem Antriebsmotor und einem Verbraucher
JP3431651B2 (ja) * 1992-12-28 2003-07-28 日立建機株式会社 作業車両の走行用油圧モータ駆動回路
DE19524189C2 (de) * 1995-07-03 1997-07-17 Brueninghaus Hydromatik Gmbh Hydrostatischer Antrieb mit nachgeschaltetem Lastschaltgetriebe
JP4521108B2 (ja) * 2000-11-06 2010-08-11 ヤンマー株式会社 作業車両のｈｓｔ斜板制御機構
JP2002174333A (ja) * 2000-12-05 2002-06-21 Hitachi Constr Mach Co Ltd ホイール走行式作業車両
DE10133358B4 (de) * 2001-07-10 2006-03-16 Brueninghaus Hydromatik Gmbh Hydrostatischer Antrieb und Verfahren zum Wechseln von Gängen eines einem hydrostatischen Getriebe nachgeschalteten Schaltgetriebes
EP1500850B1 (fr) * 2002-04-26 2011-06-08 Hitachi Construction Machinery Co., Ltd. Dispositif de commande de deplacement d'un vehicule a entrainement hydraulique, vehicule a entrainement hydraulique et pelle hydraulique sur roues
DE102005058937A1 (de) * 2005-10-27 2007-05-31 Brueninghaus Hydromatik Gmbh Verfahren und Getriebeanordnung zum Wechseln von Gangstufen
CN101479508A (zh) * 2006-06-28 2009-07-08 布鲁宁赫斯海诺马帝克有限公司 控制传动比的方法
JP4295308B2 (ja) * 2006-12-04 2009-07-15 日立建機株式会社 作業車両の走行駆動装置
JP5543117B2 (ja) 2009-02-25 2014-07-09 株式会社岡村製作所 椅子の背凭れ装置

Patent Citations (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US4621495A (en) * 1983-01-13 1986-11-11 Stensele Mekaniska Verkstad Ab Synchronized mechanical-hydrostatic gearbox
US20070137338A1 (en) * 2005-09-30 2007-06-21 Kubota Corporation Speed control structure and method for work vehicle
US20090259374A1 (en) * 2006-06-28 2009-10-15 Brueninghaus Hydromatik Gmbh Method of controlling a transmission ratio

Cited By (4)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20140138177A1 (en) * 2011-09-07 2014-05-22 Hitachi Construction Machinery Co., Ltd. Construction machine
US9139983B2 (en) * 2011-09-07 2015-09-22 Hitachi Construction Machinery Co., Ltd. Construction machine
CN107310384A (zh) * 2017-07-27 2017-11-03 天津工程机械研究院有限公司 一种全液压行走装载机传动系统
US11384511B2 (en) * 2019-03-29 2022-07-12 Hitachi Construction Machinery Co., Ltd. Wheeled work vehicle

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US20160194854A1 (en) 2016-07-07
JP2012052580A (ja) 2012-03-15
KR20130124475A (ko) 2013-11-14
EP2589836A1 (fr) 2013-05-08
CN103026099A (zh) 2013-04-03
JP5301509B2 (ja) 2013-09-25
EP2589836A4 (fr) 2015-09-23

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