Abstract: A flow rate control apparatus for construction equipment includes: a boom cylinder driven by hydraulic fluid; a first control valve for controlling a hydraulic fluid flow supplied to the boom cylinder; an option actuator driven by hydraulic fluid; a second control valve for controlling a hydraulic fluid flow supplied to the option actuator; a boom cylinder manipulation lever and an option actuator manipulation lever; a confluence line selectively confluence the hydraulic fluid supplied to the boom cylinder with the hydraulic fluid of the option actuator; a center bypass switching valve provided at the furthest downstream side of a fluid supply path of the first hydraulic pump; a confluence switching valve selectively opening and closing the confluence line; a confluence selection valve applying a pilot pressure to the confluence switching valve; and a controller for controlling the confluence selection valve.

Abstract: A straight traveling apparatus for a construction machine and a control method thereof are provided which can allow a curved travel when the working device is operated during the curved travel.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent a loss of pressure during a combined work.

Abstract: Disclosed are a control device for confluence flow rate of a working device and a control method therefor, the control device being capable of minutely operating a working device when a flow rate supplied to the working device is merged or blocked.

Abstract: A hydraulic circuit for construction machinery having a floating function, according to the present invention, is provided with: two or more hydraulic pumps; a hydraulic cylinder connected to the hydraulic pumps; a boom driving control valve provided on the flow path between the hydraulic pump on one side and the hydraulic cylinder; a boom confluence control valve provided on the flow path between the hydraulic pump on the other side and the hydraulic cylinder; an operating lever; a first sensor for measuring the hydraulic fluid pressure of a large chamber of the hydraulic cylinder; a second sensor for measuring the boom lowering pilot pressure applied to one end of the boom driving control valve; a control valve provided on the flow path between the operating lever and the other ends of the boom driving control valve and the boom confluence control valve.

Abstract: A flow control device for a construction machine including a first hydraulic cylinder and a second hydraulic cylinder connected to a hydraulic pump, which is connected to an engine. A first control valve and a second control valve are also included. A regeneration flow path is configured to supplement and reuse hydraulic fluid that returns to a hydraulic tank during a retractable drive of the first hydraulic cylinder. A regeneration valve is installed in the regeneration flow path. A pressure compensation type flow control valve is installed in a meter-in flow path of a spool of the first control valve, and is configured to limit the flow rate of the hydraulic fluid supplied from the hydraulic pump to the first hydraulic cylinder during a combined operation of the first and second hydraulic cylinders.

Abstract: A flow rate control apparatus for construction equipment includes: a boom cylinder driven by hydraulic fluid; a first control valve for controlling a hydraulic fluid flow supplied to the boom cylinder; an option actuator driven by hydraulic fluid; a second control valve for controlling a hydraulic fluid flow supplied to the option actuator; a boom cylinder manipulation lever and an option actuator manipulation lever; a confluence line selectively confluence the hydraulic fluid supplied to the boom cylinder with the hydraulic fluid of the option actuator; a center bypass switching valve provided at the furthest downstream side of a fluid supply path of the first hydraulic pump; a confluence switching valve selectively opening and closing the confluence line; a confluence selection valve applying a pilot pressure to the confluence switching valve; and a controller for controlling the confluence selection valve.

Abstract: A hydraulic system for a construction machine having a protection device is disclosed, which can limit a flow rate of hydraulic fluid that is discharged from a hydraulic pump in accordance with a hydraulic fluid temperature and notify an operator of information on the hydraulic fluid temperature.

Abstract: Disclosed is a hydraulic circuit for construction equipment for controlling to selectively supply a hydraulic oil from a hydraulic pump to a hydraulic cylinder for driving a boom. The hydraulic circuit for construction equipment, according to the present invention, comprises: a hydraulic cylinder driven by a hydraulic oil of a hydraulic pump; a direction control valve installed on the oil passage between the hydraulic pump and the hydraulic cylinder; an operating device installed on the oil passage between a pilot pump and the direction control valve; a center by-pass switching valve installed at the most downstream side of a center by-pass passage of the hydraulic pump; a pressure detection sensor that detects the pressure of a hydraulic oil at the large chamber side of the hydraulic cylinder; a jack-up switching valve installed on the oil passage between the operating device and the center by-pass switching valve; and a flow control valve installed in the spool of the direction control valve.

Abstract: A straight traveling apparatus for a construction machine and a control method thereof are provided which can allow a curved travel when the working device is operated during the curved travel.

Abstract: Disclosed is a lower track for mounting rubber pads on a track shoe to be attachable and detachable after assembling a steel plate which is adhered with divisionally formed rubber pads as a single unit without additionally perforating coupling through-holes in the track shoe when the rubber pad which forms the lower track and the track shoe which is formed of a metal material are coupled. The lower track of a crawler excavator according to the present invention comprises: first and second rubber pads which are divisionally formed; a first steel plate which supports the bottom surface of the first rubber pad by surrounding the same, and has first hooks formed on the bottom surface thereof and coupling holes formed in a connection stepped-portion.

Abstract: Disclosed is a drive control device for the construction equipment capable of reducing shock generation and smoothly operating a work device when the work device is operated during the driving, which comprises; a first and second hydraulic pumps and a pilot pump, a first work device and a first drive motor operated by a hydraulic oil of the first hydraulic pump, a second work device and a second drive motor operated by a hydraulic oil of the second hydraulic pump, a first drive control valve and a first work device control valve that are provided on the supply path of the first hydraulic pump, a second drive control valve and a second work device control valve that are provided on the supply path of the second hydraulic pump, a linear drive control valve that is provided at the upper side of the supply path of the second hydraulic pump, a parallel path having an inlet branched and connected to the upper side of the supply path of the second hydraulic pump and an outlet connected to the inlet port of the secon

Abstract: Disclosed are a control device for confluence flow rate of a working device and a control method therefor, the control device being capable of minutely operating a working device when a flow rate supplied to the working device is merged or blocked.

Abstract: Disclosed are a hydraulic circuit for using a hydraulic fluid in a hydraulic pump in another hydraulic actuator, during levelling and grading work by means of an excavator, and a method for controlling a floating function.

Abstract: A hydraulic circuit for a construction machine is disclosed, which can prevent a loss of pressure during a combined work.

Abstract: Disclosed is a system for controlling a hydraulic pump in a construction machine which can reduce the discharge flow of the hydraulic pump in proportion to the load pressure of the hydraulic pump to enhance operability by the driver. The present invention provides the system for controlling the hydraulic pump in the construction machine, which is characterized by detecting the discharge pressure of the hydraulic pump and the operation activity of an operation lever, and comparing the detected discharge pressure of the hydraulic pump and a predetermined pressure value, and when the detected discharge pressure exceeds the predetermined pressure value, the maximum dischargeable flow of the hydraulic pump is reduced in proportion to the difference between the detected pressure and the predetermined pressure value.

Abstract: A hydraulic system for a construction machine having a protection device is disclosed, which can limit a flow rate of hydraulic fluid that is discharged from a hydraulic pump in accordance with a hydraulic fluid temperature and notify an operator of information on the hydraulic fluid temperature.

Abstract: Disclosed are a flow control device and a flow control method for a construction machine for preventing the loss of fluid exhausted from a hydraulic pump when a boom and an arm of an excavator are operated in combination.

Abstract: A hydraulic pump control system provided in a construction machine such as an excavator is provided. According to the hydraulic pump control system, a loss of a flow rate is reduced by initially supplying hydraulic fluid as much as necessary from a hydraulic pump to a hydraulic motor in order to accelerate a swing movement of an upper frame against a lower traveling structure or to make an upper swing structure swing.

Abstract: A flow control valve for a construction machine is provided, which can constantly control a flow rate of hydraulic fluid supplied to a hydraulic actuator through a flow control spool in a spool. The flow control valve for a construction machine, having a valve body in which a supply passage communicating with a pump passage and actuator ports connected to a hydraulic actuator are formed, and a spool installed in the valve body to be shifted, includes a flow control spool shifted in the spool to variably control a cross-sectional area of a passage connected to the one actuator port if a flow rate of the hydraulic fluid that flows through the supply passage is higher than a set flow rate, a first passage formed on the spool to communicate with the supply passage and a second passage formed on the spool to communication with the one actuator port and having a cross-sectional area that is varied depending on the shifting of the flow control spool.