Construction machine

• US 10,450,725 B2
• Filed: 12/05/2016
• Issued: 10/22/2019
• Est. Priority Date: 12/18/2015
• Status: Active Grant

• Current Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Original Assignee: Hitachi Construction Machinery Company Limited (Hitachi, Ltd.)
• Inventors: Kobayashi, Hiroyuki, Sakamoto, Hiroshi, Tsuruga, Yasutaka
• Primary Examiner(s): Badii, Behrang
• Assistant Examiner(s): Greene, Daniel L
• Application Number:
  US15/768,841
• Publication Number:
  US 20180305898A1
• Time in Patent Office: 1,051 Days
• CPC Class Codes: E02F 3/435 for dipper-arms, backhoes or the like
• CPC Class Codes: E02F 9/20 Drives; Control devices gearings in general F16H; controlling in general G05; electric multi-motor drives H02K, H02P
• CPC Class Codes: E02F 9/2228 including an electronic controller
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: E02F 9/2267 Valves or distributors position of valves arrangements on upper-structures E02F9/0875
• CPC Class Codes: E02F 9/2271 Actuators and supports therefor and protection therefor
• CPC Class Codes: E02F 9/2285 Pilot-operated systems
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: E02F 9/2296 Systems with a variable displacement pump
• CPC Class Codes: F15B 11/04 for controlling the speed F15B11/024 takes precedence
• CPC Class Codes: F15B 11/08 with only one servomotor
• CPC Class Codes: F15B 2211/30525 Directional control valves, e.g. 4/3-directional control valve
• CPC Class Codes: F15B 2211/526 electrically or electronically
• CPC Class Codes: F15B 2211/6653 Pressure control

Abstract

A construction machine that can ensure an initial response that varies in accordance with a hydraulic actuator in a similar fashion to a case of adopting a hydraulic pilot-type operation device is provided. A controller 100 of a hydraulic excavator outputs a command current for driving the corresponding solenoid proportional valve (i.e. some of solenoid proportional valves 41a, 41b, 42a to 42d, 43a to 43d, 44a and 44b) in response to an operation signal from an electric lever-type work operation device 2a or 2b, and includes a correction function to correct the command current such that the command current is higher than a target current corresponding to an operation amount of the operation device for preset predetermined time at a time of starting to operate the operation device from a neutral position thereof. This correction function corrects only the command current to the bucket solenoid proportional valves 44a and 44b.

Claims

1. A construction machine comprising:

a plurality of hydraulic pumps;

a first directional control valve that controls a flow of a hydraulic fluid from one of the hydraulic pumps to a first hydraulic actuator;

a pair of first solenoid proportional valves that generate and output pilot pressure for driving the first directional control valve;

a plurality of second directional control valves that control the flow of the hydraulic fluid from the plurality of hydraulic pumps to a second hydraulic actuator;

a plurality of pairs of second solenoid proportional valves that generate and output pilot pressures for driving the plurality of second directional control valves;

at least one electric lever-type operation device that outputs a first operation signal for operating the first hydraulic actuator and that outputs a second operation signal for operating the second hydraulic actuator; and

a controller that outputs a first command current for driving the first solenoid proportional valve in response to the first operation signal from the operation device, and that outputs a second command current for driving the second solenoid proportional valves in response to the second operation signal from the operation device, wherein

the controller includes a correction function to correct a command current in such a manner that the command current is higher than a target current corresponding to an operation amount of the operation device for preset predetermined time at a time of starting to operate the operation device from a neutral position of the operation device, and

the correction function of the controller corrects the command current such that the controller corrects the first command current and does not correct the second command current or such that a correction value of the first command current is higher than a correction value of the second command current.

2. The construction machine according to claim 1, wherein

the construction machine according to claim 1 is a hydraulic excavator,

the first hydraulic actuator is a bucket cylinder,

the second hydraulic actuator is an arm cylinder and a boom cylinder, and

the correction function of the controller corrects the first command current for driving the bucket cylinder and does not correct the second command current for driving the arm cylinder and the second command current for driving the boom cylinder.

3. The construction machine according to claim 1, wherein

the construction machine according to claim 1 is a hydraulic excavator,

the first hydraulic actuator is a bucket cylinder,

the second hydraulic actuator is an arm cylinder and a boom cylinder, and

the correction function of the controller corrects the first command current and the second command currents in such a manner that a relationship of a correction value y1 of the first command current for driving the bucket cylinder>

a correction value y2 of the second command current for driving the arm cylinder>

a correction value y3 of the second command current for driving the boom cylinder is satisfied.

4. The construction machine according to claim 3, wherein

the controller further includes a function to selectively execute a manual control mode for driving the bucket cylinder, the arm cylinder, and the boom cylinder in accordance with operation on the operation device, and an automatic control mode for driving the bucket cylinder, the arm cylinder, and the boom cylinder in such a manner that an action of any one of a bucket, an arm, and a boom is limited or adjusted on basis of the operation on the operation device, and

the correction function of the controller,

corrects the first and second command values in such a manner that a relationship of the correction value y1 of the first command current for driving the bucket cylinder>

the correction value y2 of the second command current for driving the arm cylinder>

the correction value y3 of the second command current for driving the boom cylinder is satisfied in a case of the manual control mode, and,

corrects the first command current for driving the bucket cylinder, the second command current for driving the arm cylinder, and the second command current for driving the boom cylinder to a correction value y4 larger than the correction values y1, y2, and y3 in a case of the automatic control mode.