(19)
(11) EP 2 937 474 A3

(12) EUROPEAN PATENT APPLICATION

(88) Date of publication A3:
13.04.2016 Bulletin 2016/15

(43) Date of publication A2:
28.10.2015 Bulletin 2015/44

(21) Application number: 15164484.6

(22) Date of filing: 21.04.2015
(51) International Patent Classification (IPC): 
E02F 9/22(2006.01)
(84) Designated Contracting States:
AL AT BE BG CH CY CZ DE DK EE ES FI FR GB GR HR HU IE IS IT LI LT LU LV MC MK MT NL NO PL PT RO RS SE SI SK SM TR
Designated Extension States:
BA ME
Designated Validation States:
MA

(30) Priority: 21.04.2014 KR 20140047451

(71) Applicant: Doosan Infracore Co., Ltd.
Dong-gu Incheon 401-020 (KR)

(72) Inventors:
  • Sohn, Won Sun
    Seoul 157-865 (KR)
  • Sohn, Dong Youn
    Seoul 03737 (KR)
  • Kim, In Dong
    Gyeonggi-do 410-762 (KR)

(74) Representative: Isarpatent 
Patentanwälte Behnisch Barth Charles Hassa Peckmann & Partner mbB Friedrichstrasse 31
80801 München
80801 München (DE)

   


(54) HYDRAULIC SYSTEM FOR CONSTRUCTION MACHINERY


(57) The present disclosure relates to a hydraulic system for construction machinery. According to the hydraulic system for construction machinery according to the exemplary embodiment of the present disclosure, during a traveling mode, hydraulic oil discharged from a first main pump (11) merges with hydraulic oil discharged from a second main pump (12), and the merged hydraulic oil is provided to a traveling motor (80), thereby improving traveling performance. In addition, according to the hydraulic system for construction machinery according to the exemplary embodiment of the present disclosure, even in a situation in which the first and third control valve units (51, 53) cannot be normally controlled for an unknown reason, the overspeed traveling may be prevented by restricting a maximum discharge flow rate of the first main pump (11) in the traveling mode, thereby ensuring traveling performance and preventing durability of a traveling system from deteriorating.







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