Hydraulic drive unit of hydraulic excavator

• US 10,472,805 B1
• Filed: 10/23/2018
• Issued: 11/12/2019
• Est. Priority Date: 05/11/2018
• Status: Active Grant

• Current Assignee: Takeuchi Mfg. Co.Ltd
• Original Assignee: Takeuchi Mfg. Co.Ltd
• Inventors: Kumeuchi, Kengo, Shimizu, Koichi, Kobayashi, Yuta, Okutani, Shumpei, Watanabe, Takahiro
• Primary Examiner(s): Leslie, Michael
• Assistant Examiner(s): Collins, Daniel S
• Application Number:
  US16/168,033
• Publication Number:
  US 20190345695A1
• Time in Patent Office: 385 Days
• CPC Class Codes: E02F 3/30 with a dipper-arm pivoted on a cantilever beam , i.e. boom
• CPC Class Codes: E02F 3/325 Backhoes of the miniature type
• CPC Class Codes: E02F 3/425 Drive systems for dipper-arms, backhoes or the like
• CPC Class Codes: E02F 3/961 with several digging elements or tools mounted on one machine for backhoes E02F3/964 takes precedence
• CPC Class Codes: E02F 3/964 of several tools mounted on one machine E02F3/962 takes precedence
• CPC Class Codes: E02F 9/123 Drives or control devices specially adapted therefor E02F9/125 and E02F9/128 take precedence
• CPC Class Codes: E02F 9/2062 Control of propulsion units for control of the prime mover depending on the load in a hydraulic or pneumatic drive E02F9/2246
• CPC Class Codes: E02F 9/2095 Control of electric, electro-mechanical or mechanical equipment not otherwise provided for, e.g. ventilators, electro-driven fans control of hydraulic driven equipment E02F9/22
• CPC Class Codes: E02F 9/2221 Control of flow rate; Load sensing arrangements E02F9/2203 take precedence over E02F9/2221
• CPC Class Codes: E02F 9/2246 Control of prime movers, e.g. depending on the hydraulic load of work tools
• CPC Class Codes: E02F 9/2292 Systems with two or more pumps
• CPC Class Codes: F15B 11/165 for adjusting the pump output or bypass in response to demand
• CPC Class Codes: F15B 11/17 using two or more pumps
• CPC Class Codes: F15B 2211/20515 Electric motor
• CPC Class Codes: F15B 2211/20576 with multiple pumps
• CPC Class Codes: F15B 2211/255 Flow control functions
• CPC Class Codes: F15B 2211/275 Control of the prime mover, e.g. hydraulic control
• CPC Class Codes: F15B 2211/428 actuated by fluid pressure
• CPC Class Codes: F15B 2211/6313 the pressure being a load pressure
• CPC Class Codes: F15B 2211/6651 Control of the prime mover, e.g. control of the output torque or rotational speed
• CPC Class Codes: F15B 2211/6654 : Flow rate control
• CPC Class Codes: F15B 2211/7053 : Double-acting output members
• CPC Class Codes: F15B 2211/7058 : Rotary output members
• CPC Class Codes: F15B 2211/7135 : Combinations of output members of different types, e.g. single-acting cylinders with rotary motors

Abstract

A hydraulic drive unit of a hydraulic excavator is configured to include a first hydraulic pump (P1) that discharges a hydraulic oil for activating a boom cylinder (36) and the like, a first electric motor (M1) that drives the first hydraulic pump (P1), a hydraulic pump for revolution (P2) that discharges a hydraulic oil for activating a revolution motor (26), a second electric motor (M2) that drives the hydraulic pump for revolution (P2), and a motor control device (150) that controls the rotation of the first electric motor (M1) and that of the second electric motor (M2). The motor control device (150) is configured such that when the revolution of the revolving body is not activated by the revolution motor (26), control to deactivate the second electric motor (M2) is performed.

Claims

1. A hydraulic drive unit of a hydraulic excavator, for use in a hydraulic excavator comprising:

a traveling body capable of traveling;

a revolving body provided on the traveling body in a horizontally revolvable manner and horizontally revolved by a revolution hydraulic actuator; and

an excavator device provided to the revolving body and driven by a plurality of activation hydraulic actuators,

the hydraulic drive unit including;

a first hydraulic pump that discharges a hydraulic oil for activating the plurality of activation hydraulic actuators;

a first electric motor that drives the first hydraulic pump;

a hydraulic pump for revolution that discharges a hydraulic oil for activating the revolution hydraulic actuator;

a second electric motor that drives the hydraulic pump for revolution; and

a motor controller that controls the rotation of the first electric motor and that of the second electric motor,

an actuator operation unit operated to activate each of the plurality of activation hydraulic actuators and the revolution hydraulic actuator;

a plurality of first control valves that control the flow rates of respective hydraulic oils supplied from the first hydraulic pump to the plurality of activation hydraulic actuators;

a revolution control valve that controls the flow rate of a hydraulic oil supplied from the hydraulic pump for revolution to the revolution hydraulic actuator; and

a pilot pressure supply unit that supplies a pilot pressure for driving each of the plurality of first control valves and the revolution control valve according to the operation of the actuator operation unit,

wherein the pilot pressure supply unit generates the pilot pressure using a hydraulic oil discharged from the first hydraulic pump, and

the hydraulic drive unit being characterized in that when the revolution of the revolving body is not activated by the revolution hydraulic actuator, the motor controller performs control to deactivate the second electric motor.

2. The hydraulic drive unit of a hydraulic excavator according to claim 1, wherein the motor controller controls the rotation of the second electric motor, thereby controlling the revolution speed at the time of activating the revolution of the revolving body by the revolution hydraulic actuator.

3. The hydraulic drive unit of a hydraulic excavator according to claim 1, comprising a pressure sensor that detects the maximum load pressure among the load pressures of the plurality of activation hydraulic actuators, and wherein

the motor controller controls the rotation of the first electric motor, thereby controlling the discharge flow rate of the first hydraulic pump in such a manner that the discharge pressure of the first hydraulic pump is higher than the maximum load pressure.

4. The hydraulic drive unit of a hydraulic excavator according to claim 1, wherein when at least one of the plurality of activation hydraulic actuators and the revolution hydraulic actuator are activated together, the motor controller controls the rotation of the first electric motor, thereby controlling the discharge flow rate of the first hydraulic pump in such a manner that the discharge flow rate of the first hydraulic pump is reduced by the discharge flow rate of the hydraulic pump for revolution.

5. The hydraulic drive unit of a hydraulic excavator according to claim 1, wherein the first hydraulic pump discharges a hydraulic oil for activating a traveling hydraulic motor provided to the traveling body.