HYDRAULIC DRIVE DEVICE FOR CONSTRUCTION MACHINE

• Main Authors: TSURUGA YASUTAKA, NOBEZAWA HIROYUKI, YAMADA KENJI, OKAZAKI YASUHARU, TAKAHASHI KIWAMU
• Format: Patent
• Language: English; Korean
• Published: 28.03.2016
• 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; SOIL SHIFTING; SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; WEAPONS

타방의 유압 펌프의 흡수 토오크를 순유압적인 구성에 의해 양호한 정밀도로 검출하여 일방의 유압 펌프측에 피드백함으로써, 전체 토오크 제어를 양호한 정밀도로 행하여, 원동기의 정격 출력 토오크를 유효 이용하고 또한 탑재성을 향상시킨다. 이 목적을 위하여, 제 1 유압 펌프(1a)의 토출압과 로드 센싱 구동 압력이 유도되고, 제 2 유압 펌프(1b)의 흡수 토오크를 모의한 특성이 되도록 제 2 유압 펌프(1b)의 토출압을 보정하여 출력하는 토오크 피드백 회로(31)와, 이 토오크 피드백 회로(31)의 출력압이 유도되고, 이 출력압이 높아짐에 따라서 제 1 유압 펌프(1a)의 용량을 감소시켜 최대 토오크(T1max)가 감소하도록 제 1 유압 펌프(1a)의 용량을 제어하는 토오크 피드백 피스톤(32a, 32b)을 설치한다. 토오크 피드백 회로(31)는 분압 스로틀부(34a, 34b), 분압 밸브(35a, 35b), 릴리프 밸브(37a, 37b)를 갖는다. It is an object of the present invention to accurately detect the absorption torque of the other of two hydraulic pumps by a purely hydraulic structure and feed the absorption torque to one of the two hydraulic pumps, thereby to accurately perform a total torque control, effectively utilize a rated output torque of a prime mover, and enhance mountability. To achieve the object, there are provided: a torque feedback circuit 31 to which the delivery pressure of a first hydraulic pump 1a and a load sensing drive pressure are introduced, which modifies the delivery pressure of a second hydraulic pump 1b to provide a characteristic simulating the absorption torque of the second hydraulic pump 1b, and which outputs the modified pressure; and torque feedback pistons 32a, 32b to which the output pressure of the torque feedback circuit 31 is introduced, and which control the capacity of the first hydraulic pump 1a to decrease the capacity of the first hydraulic pump 1a and decrease a maximum torque T1max as the output pressure becomes higher. The torque feedback circuit 31 includes pressure dividing restrictor parts 34a, 34b, pressure dividing valves 35a, 35b, and relief valves 37a, 37b.