CONSTRUCTION MACHINE

To provide a construction machine equipped with a hydraulic drive system that performs load sensing control, while ensuring good operability of a hydraulic pump, and suppressing a breathing phenomenon (cavitation) due to the shortage of pressure oil on the meter-in side due to the response delay of...

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Main Authors NAKAMURA NATSUKI, TAKEBAYASHI KEIFUMI, YOSHIDA HAJIME, OKA DAISUKE, KUWABARA TAKUMA
Format Patent
LanguageEnglish
Japanese
Published 17.09.2020
Subjects
BLASTING
DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR
DREDGING
FIXED CONSTRUCTIONS
FLUID-PRESSURE ACTUATORS
FLUID-PRESSURE ACTUATORS, e.g. SERVO-MOTORS
FOUNDATIONS
HEATING
HYDRAULIC ENGINEERING
HYDRAULICS OR PNEUMATICS IN GENERAL
LIGHTING
MECHANICAL ENGINEERING
POSITIVE DISPLACEMENT MACHINES FOR LIQUIDS
PUMPS
PUMPS FOR LIQUIDS OR ELASTIC FLUIDS
SOIL SHIFTING
SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL
WEAPONS
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Summary:To provide a construction machine equipped with a hydraulic drive system that performs load sensing control, while ensuring good operability of a hydraulic pump, and suppressing a breathing phenomenon (cavitation) due to the shortage of pressure oil on the meter-in side due to the response delay of the pump.SOLUTION: A construction machine having an LS control valve 17b that selectively communicates an LS controlled tilting piston 17c with a pilot hydraulic source 33 and a tank T to control the drive of the LS controlled tilting piston 17c comprises a response control switching valve 17f provided in an oil passage connecting the LS control valve 17b and the LS control tilting piston 17c and switching between a throttle position and a communication position based on the maximum load pressure of a plurality of actuators 3a, 3b, 3c ... The response control switching valve 17f switches to the communication position when the maximum load pressure is equal to or less than the tank pressure, and switches to the throttle position when the maximum load pressure is higher than the tank pressure.SELECTED DRAWING: Figure 2 【課題】ロードセンシング制御を行う油圧駆動システムを搭載し、油圧ポンプ良好な操作性を確保しつつ、ポンプの応答遅れによるメータイン側の圧油の不足による息継ぎ現象（キャビテーション）を抑えることができる建設機械を提供する。【解決手段】ＬＳ制御傾転ピストン１７ｃをパイロット油圧源３３とタンクＴとに選択的に連通させ、ＬＳ制御傾転ピストン１７ｃの駆動を制御するＬＳ制御弁１７ｂを有する建設機械において、ＬＳ制御弁１７ｂとＬＳ制御傾転ピストン１７ｃとを連絡する油路に設けられ、複数のアクチュエータ３ａ，３ｂ，３ｃ...の最高負荷圧に基づいて絞り位置と連通位置との間で切り換わる応答制御切換弁１７ｆを備え、応答制御切換弁１７ｆは、前記最高負荷圧がタンク圧以下の場合は連通位置となり、前記最高負荷圧がタンク圧より高い圧力の場合は絞り位置に切り換わる。【選択図】 図２
Bibliography:Application Number: JP20190045223