US20140331660A1 - Hydraulic Machinery - Google Patents

Hydraulic Machinery Download PDF

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Publication number
US20140331660A1
US20140331660A1 US14/365,555 US201214365555A US2014331660A1 US 20140331660 A1 US20140331660 A1 US 20140331660A1 US 201214365555 A US201214365555 A US 201214365555A US 2014331660 A1 US2014331660 A1 US 2014331660A1
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United States
Prior art keywords
pressure
rotation speed
pump
engine
hydraulic
Prior art date
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Abandoned
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US14/365,555
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English (en)
Inventor
Yoshihiko Hata
Shogo Tada
Current Assignee (The listed assignees may be inaccurate. Google has not performed a legal analysis and makes no representation or warranty as to the accuracy of the list.)
Caterpillar SARL
Original Assignee
Caterpillar SARL
Priority date (The priority date 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 date listed.)
Filing date
Publication date
Application filed by Caterpillar SARL filed Critical Caterpillar SARL
Assigned to CATERPILLAR SARL reassignment CATERPILLAR SARL ASSIGNMENT OF ASSIGNORS INTEREST (SEE DOCUMENT FOR DETAILS). Assignors: HATA, YOSHIHIKO, TADA, Shogo
Publication of US20140331660A1 publication Critical patent/US20140331660A1/en
Abandoned legal-status Critical Current

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Classifications

    • 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
    • E02F9/2246—Control of prime movers, e.g. depending on the hydraulic load of work tools
    • 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
    • E02F9/2285—Pilot-operated systems
    • 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
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D29/00—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto
    • F02D29/04—Controlling engines, such controlling being peculiar to the devices driven thereby, the devices being other than parts or accessories essential to engine operation, e.g. controlling of engines by signals external thereto peculiar to engines driving pumps
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/0205—Circuit arrangements for generating control signals using an auxiliary engine speed control
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/04—Accumulators
    • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
    • F15B1/083—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor the accumulator having a fusible plug
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F15—FLUID-PRESSURE ACTUATORS; HYDRAULICS OR PNEUMATICS IN GENERAL
    • F15B—SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
    • F15B1/00—Installations or systems with accumulators; Supply reservoir or sump assemblies
    • F15B1/02—Installations or systems with accumulators
    • F15B1/04—Accumulators
    • F15B1/08—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor
    • F15B1/24—Accumulators using a gas cushion; Gas charging devices; Indicators or floats therefor with rigid separating means, e.g. pistons
    • F—MECHANICAL ENGINEERING; LIGHTING; HEATING; WEAPONS; BLASTING
    • F02—COMBUSTION ENGINES; HOT-GAS OR COMBUSTION-PRODUCT ENGINE PLANTS
    • F02D—CONTROLLING COMBUSTION ENGINES
    • F02D41/00—Electrical control of supply of combustible mixture or its constituents
    • F02D41/02—Circuit arrangements for generating control signals
    • F02D41/021—Introducing corrections for particular conditions exterior to the engine

Definitions

  • the present invention relates to the technical field of a hydraulic work machine such as a hydraulic shovel.
  • hydraulic work machines such as hydraulic shovels
  • hydraulic actuators a hydraulic motor and a hydraulic cylinder
  • improvements in fuel efficiency and reductions of exhaust gases in these hydraulic work machines have been in progress.
  • One studied method of achieving the objects is setting the engine rotation speed to be low during normal operation. However, when the engine rotation speed is thus set to be low, the rotation speed of the hydraulic pump, driven by the engine, is also lowered. Thus, the maximum flow rate that can be supplied from the hydraulic pump to the hydraulic actuator is reduced. As a result, a problem arises in that a sufficient speed cannot be obtained when the hydraulic actuator is to be operated at a high speed in a light load state.
  • Patent Document 1 A technique of controlling the engine rotation speed in accordance with the load pressure to improve fuel efficiency in the light load state, is known (see, for example, Patent Document 1).
  • the load on the hydraulic actuator is light and the discharge pressure of the hydraulic pump is low, a desired discharge flow rate is obtained by lowering the engine rotation speed and increasing the capacity of the hydraulic pump.
  • Patent Document 1 Japanese Patent Application Laid-open No. H6-81802
  • a hydraulic work machine including: an engine; a variable capacity hydraulic pump driven by the engine; a hydraulic actuator that operates using the hydraulic pump as a hydraulic pressure supply source; a control valve that is displaced in accordance with an operation amount of a hydraulic actuator operation means so as to control a pressure oil supply flow rate from the hydraulic pump to the hydraulic actuator; a negative control circuit that outputs a negative control signal pressure to capacity varying means of the hydraulic pump to increase or decrease a discharge flow rate of the hydraulic pump in accordance with a displacement amount of the control valve; an engine rotation speed setting means operated to set a target rotation speed of the engine; and an engine control device that controls a rotation speed of the engine based on the target rotation speed set with the engine rotation speed setting means.
  • the hydraulic work machine further includes pump pressure detection means for detecting a discharge pressure of the hydraulic pump, pump capacity detection means for detecting a capacity of the hydraulic pump, and negative control signal pressure detection means for detecting the negative control signal pressure.
  • the engine control device performs engine rotation speed increasing control for increasing the engine rotation speed to be higher than the target rotation speed set with the engine rotation speed setting means, when the discharge pressure of the hydraulic pump detected by the pump pressure detection means is not larger than a set pump pressure set in advance as a pump discharge pressure in a light load state, the pump capacity detected by the pump capacity detection means is at a maximum capacity of the hydraulic pump, and the negative control signal pressure detected by the negative control signal pressure detection means is not larger than a set signal pressure set in advance as a negative control signal pressure in a fully operated state of the hydraulic actuator operation means .
  • the engine rotation speed increases when the engine rotation speed increasing control is performed, and thus the discharge flow rate of the hydraulic pump can be increased. This can prevent insufficient speed due to an insufficient supply flow rate to the hydraulic actuator in the case where an operation requiring high speed at a light load is performed, whereby excellent operability is guaranteed and an attempt to improve work efficiency is largely facilitated.
  • FIG. 1 is a hydraulic pressure control circuit diagram of a hydraulic shovel.
  • FIG. 2 is a flowchart of engine rotation speed control.
  • FIG. 1 A hydraulic pressure control circuit provided to a hydraulic shovel, as an example of a hydraulic work machine, is illustrated in FIG. 1 , in which 1 denotes an engine, 2 denotes a variable capacity hydraulic pump driven by the engine 1 , 2 a denotes capacity varying means of the hydraulic pump 2 , 3 denotes an oil tank, and A denotes hydraulic actuators that operate using the hydraulic pump 2 as a hydraulic pressure supply source.
  • the hydraulic shovel includes, as the hydraulic actuators A, left and right drive motors, a swing motor, a boom cylinder, an arm cylinder, and a bucket cylinder.
  • an axial piston pump in which a capacity changes in accordance with a inclination angle of a swash plate, is used as the hydraulic pump 2 .
  • control valve 4 denotes control valves that perform oil supply/discharge control for the respective hydraulic actuators A.
  • the control valve 4 is configured to be positioned at a neutral position N in which pressure oil is not supplied to the hydraulic actuator A, in a state where no pilot pressure is supplied to pilot ports 4 a and 4 b, and is configured to be displaced when the pilot pressure is supplied to the pilot ports 4 a and 4 b and to be switched to an operation position X or Y in which a discharged oil from the hydraulic pump 2 is supplied to the hydraulic actuator A.
  • a control is performed in such a manner that the displacement amount (movement stroke) of the control valve 4 increases/decreases in accordance with the increase/decrease of the pilot pressure input to the pilot ports 4 a and 4 b, and a pressure oil supply flow rate to the hydraulic actuator A increases when a displacement amount of the control valve 4 increases.
  • a center bypass valve path 4 c to be connected to a center bypass oil path 5 is formed in each control valve 4 .
  • the opening amount of the center bypass valve path 4 c is at the maximum when the control valve 4 is at the neutral position N, and reduces as the displacement amount of the control valve 4 increases.
  • the pilot valve 6 denotes a pilot valve.
  • the pilot valve 6 outputs the pilot pressure to each of the pilot ports 4 a and 4 b of the control valve 4 , based on an operation on a hydraulic actuator operation device (operation devices respectively for left and right traveling, swing, the boom, the arm, and the bucket, in this embodiment) 7 .
  • a hydraulic actuator operation device operation devices respectively for left and right traveling, swing, the boom, the arm, and the bucket, in this embodiment
  • the pilot pressure output from the pilot valve 6 increases/decreases in accordance with the operation amount on the hydraulic actuator operation means 7 .
  • FIG. 1 only the pilot valve 6 that outputs the pilot pressure to the control valve 4 at the right end is illustrated, and the pilot valves 6 that output the pilot pressure to other control valves 4 are omitted because the pilot valves are the same as the right end one.
  • the center bypass oil path 5 is an oil path that is formed to extend from the hydraulic pump 2 , sequentially pass through the center bypass valve paths 4 c formed in the respective control valves 4 , and then pass through a negative control orifice 8 to reach the oil tank 3 .
  • the pressure on the upstream side of the negative control orifice 8 in the center bypass oil path 5 is input, as a negative control signal pressure, to the capacity varying means 2 a of the hydraulic pump 2 , through a signal circuit 9 .
  • the negative control signal pressure is high when the opening amount of the center bypass valve path 4 c of the control valve 4 is maximum, that is, when the control valve 4 is positioned at the neutral position N, while the negative control signal pressure becomes lower as the opening amount of the center bypass valve path 4 c becomes smaller, that is, as the displacement amount of the control valve 4 becomes larger.
  • the capacity varying means 2 a of the hydraulic pump 2 controls the discharge flow rate of the hydraulic pump 2 , in such a manner that the negative control signal pressure at a higher pressure leads to a smaller discharge flow rate of the hydraulic pump 2 , and the negative control signal pressure at a lower pressure leads to a larger discharge flow rate of the hydraulic pump 2 .
  • the center bypass valve path 4 c of the control valve 4 , the center bypass oil path 5 , the negative control orifice 8 , and the signal circuit 9 form a negative control circuit of the present invention.
  • 10 denotes an engine control device that controls the rotation speed of the engine 1 .
  • the engine control device 10 receives a signal from each of a pump pressure detection sensor (corresponding to pump pressure detection means of the present invention) 11 that detects the discharge pressure of the hydraulic pump 2 , a inclination angle detection sensor (corresponding to pump capacity detection means of the present invention) 12 that detects the inclination angle of the swash plate of the hydraulic pump 2 , a negative control signal pressure detection sensor (corresponding to negative control signal pressure detection means of the present invention) 13 that detects the negative control signal pressure, and an engine rotation speed setting means (such as an accelerator dial and an accelerator lever) 14 .
  • the engine control device 10 controls the rotation speed of the engine 1 , based on the input signals.
  • the engine rotation speed setting means 14 is an operation means used by an operator to set the target rotation speed of the engine 1 as desired.
  • the operator can set the engine rotation speed to a plurality of levels by using the engine rotation speed setting means 14 .
  • the engine rotation speed setting means 14 may enable the engine rotation speed to be set in a stepless manner.
  • the engine control device 10 receives signals from the pump pressure detection sensor 11 , the inclination angle detection sensor 12 , a negative control signal pressure detection sensor 13 , and the engine rotation speed setting means 14 (step S 1 ).
  • the engine control device 10 determines whether a negative control signal pressure Pn, detected by the negative control signal pressure detection sensor 13 , is not larger than a set signal pressure PnS (1.8 Mpa, for example) (Pn ⁇ PnS?), the set signal pressure Pns being set in advance as a negative control signal pressure when at least one hydraulic actuator operation means 7 is in a fully operated state (at least one control valve 4 is displaced by the maximum displacement amount) (step S 2 ).
  • step S 2 When “YES” is determined in step S 2 described above, that is, when the negative control signal pressure Pn is not larger than the set signal pressure PnS (Pn ⁇ PnS), it is further determined whether the discharge pressure Pp of the hydraulic pump 2 detected by the pump pressure detection sensor 11 is not larger than a set pump pressure PpS (20 MPa for example) (Pp ⁇ PpS?), the set pump pressure PpS being set in advance as a pump discharge pressure in the light load state (step S 3 ).
  • the light-load state rotation speed is higher than the target rotation speed set with the engine rotation speed setting means 14 , by a predetermined rotation speed (200 rps, for example), and is set for each target rotation speed.
  • the engine rotation speed increasing control for increasing the engine rotation speed up to the light-load state rotation speed that is higher than the target rotation speed set with the engine rotation speed setting means 14 is performed, when “YES” is determined in all of steps S 2 , S 3 , and S 4 described above, that is, when the negative control signal pressure Pn is not larger than the set signal pressure PnS (the hydraulic actuator operation means 7 is in the fully operated state), the discharge pressure Pp of the hydraulic pump 2 is not larger than the set pump pressure PpS (in the light load state), and the inclination angle S ⁇ of the swash plate of the hydraulic pump 2 is at the maximum inclination angle S ⁇ m (the capacity of the hydraulic pump 2 is at the maximum).
  • the rotation speed of the hydraulic pump 2 driven by the engine 1 , is increased by performing the engine rotation speed increasing control, whereby the discharge flow rate of the hydraulic pump 2 can be increased.
  • step S 6 when “NO” is determined in any one of steps S 2 , S 3 , and S 4 described above, that is, when the negative control signal pressure exceeds the set signal pressure (Pn>PnS), when the discharge pressure of the hydraulic pump 2 exceeds the set pump pressure (Pp>PpS), or when the inclination angle of the swash plate of the hydraulic pump 2 is not at the maximum inclination angle (S ⁇ S ⁇ m), the engine control device 10 controls the engine rotation speed so that the target rotation speed set with the engine rotation speed setting means 14 is achieved (step S 6 ).
  • the hydraulic shovel includes: the engine 1 ; the variable capacity hydraulic pump 2 driven by the engine 1 ; the hydraulic actuator A that operates using the hydraulic pump 2 as a hydraulic pressure supply source; the control valve 4 that is displaced in accordance with an operation amount of a hydraulic actuator operation means 7 so as to control a pressure oil supply flow rate from the hydraulic pump 2 to the hydraulic actuator A; the negative control circuit (the center bypass valve path 4 c of the control valve 4 , the center bypass oil path 5 , the negative control orifice 8 , and the signal circuit 9 ) that outputs the negative control signal pressure to the capacity varying means 2 a of the hydraulic pump 2 to increase or decrease a discharge flow rate of the hydraulic pump 2 in accordance with a displacement amount of the control valve 4 ; the engine rotation speed setting means 14 operated to set the target rotation speed of the engine 1 ; and the engine control device 10 that controls a rotation speed of the engine 1 based on the target rotation speed set with the engine rotation speed setting means 14 .
  • the hydraulic shovel further includes the pump pressure detection sensor 11 for detecting a discharge pressure of the hydraulic pump 2 , the inclination angle detection sensor 12 for detecting the inclination angle of the hydraulic pump 2 , and the negative control signal pressure detection sensor 13 for detecting the negative control signal pressure.
  • the engine control device 10 performs engine rotation speed increasing control for increasing the rotation speed of the engine 1 up to the light-load state rotation speed higher than the target rotation speed set with the engine rotation speed setting means 14 , when the discharge pressure of the hydraulic pump 2 detected by the pump pressure detection sensor 11 is not larger than a set pump pressure set in advance as a pump discharge pressure in the light load state, the inclination angle of the swash plate of the hydraulic pump 2 detected by the inclination angle detection sensor 12 is at the maximum inclination angle (the pump capacity is at the maximum capacity), and the negative control signal pressure detected by the negative control signal pressure detection sensor 13 is not larger than the set signal pressure set in advance as the negative control signal pressure in the fully operated state of the hydraulic actuator operation means 7 .
  • the engine rotation speed increasing control is performed for increasing the engine rotation speed up to the light-load state rotation speed higher than the target rotation speed set with the engine rotation speed setting means 14 .
  • the rotation speed of the hydraulic pump 2 also increases.
  • the present invention can be used for various hydraulic work machines such as a hydraulic shovel, including a hydraulic pump driven by an engine and a hydraulic actuator that operates using the hydraulic pump as a hydraulic pressure supply source.
US14/365,555 2011-12-16 2012-12-14 Hydraulic Machinery Abandoned US20140331660A1 (en)

Applications Claiming Priority (3)

Application Number Priority Date Filing Date Title
JP2011-275236 2011-12-16
JP2011275236A JP5614814B2 (ja) 2011-12-16 2011-12-16 油圧作業機械
PCT/JP2012/082494 WO2013089230A1 (ja) 2011-12-16 2012-12-14 油圧作業機械

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US20140331660A1 true US20140331660A1 (en) 2014-11-13

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US14/365,555 Abandoned US20140331660A1 (en) 2011-12-16 2012-12-14 Hydraulic Machinery

Country Status (6)

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US (1) US20140331660A1 (ko)
EP (1) EP2792888A4 (ko)
JP (1) JP5614814B2 (ko)
KR (1) KR20140110859A (ko)
CN (1) CN104136782B (ko)
WO (1) WO2013089230A1 (ko)

Cited By (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160061227A1 (en) * 2013-04-12 2016-03-03 Thyssenkrupp Tiefbautechnik Gmbh Vibrating ram arrangement, and method for operating the vibrating ram arrangement
WO2019050064A1 (en) * 2017-09-07 2019-03-14 Volvo Construction Equipment Ab HYDRAULIC MACHINE

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Publication number Priority date Publication date Assignee Title
JPH0742704A (ja) * 1993-07-30 1995-02-10 Yutani Heavy Ind Ltd オートアクセル装置
US6020651A (en) * 1997-06-12 2000-02-01 Hitachi Construction Machinery Co., Ltd. Engine control system for construction machine
US20100167873A1 (en) * 2007-01-18 2010-07-01 Komatsu Ltd. Engine Control Device, And Its Control Method
US8899035B2 (en) * 2009-09-04 2014-12-02 Caterpillar Sarl Hydraulic control apparatus for work machine

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US6020651A (en) * 1997-06-12 2000-02-01 Hitachi Construction Machinery Co., Ltd. Engine control system for construction machine
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Cited By (3)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
US20160061227A1 (en) * 2013-04-12 2016-03-03 Thyssenkrupp Tiefbautechnik Gmbh Vibrating ram arrangement, and method for operating the vibrating ram arrangement
US10385883B2 (en) * 2013-04-12 2019-08-20 Thyssenkrupp Infrastructure Gmbh Vibrating ram arrangement, and method for operating the vibrating ram arrangement
WO2019050064A1 (en) * 2017-09-07 2019-03-14 Volvo Construction Equipment Ab HYDRAULIC MACHINE

Also Published As

Publication number Publication date
CN104136782B (zh) 2016-03-30
JP2013124752A (ja) 2013-06-24
WO2013089230A1 (ja) 2013-06-20
EP2792888A4 (en) 2016-01-06
JP5614814B2 (ja) 2014-10-29
KR20140110859A (ko) 2014-09-17
CN104136782A (zh) 2014-11-05
EP2792888A1 (en) 2014-10-22

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AS Assignment

Owner name: CATERPILLAR SARL, SWITZERLAND

Free format text: ASSIGNMENT OF ASSIGNORS INTEREST;ASSIGNORS:HATA, YOSHIHIKO;TADA, SHOGO;REEL/FRAME:033106/0663

Effective date: 20140604

STCB Information on status: application discontinuation

Free format text: ABANDONED -- FAILURE TO PAY ISSUE FEE