CONTROLLER OF HYBRID CONSTRUCTION MACHINE

• US 20110071738A1
• Filed: 03/26/2009
• Published: 03/24/2011
• Est. Priority Date: 03/26/2008
• Status: Active Grant

• Current Assignee: KYB Corp.
• Original Assignee: Kayaba Industry Company Limited
• Inventors: Egawa, Masahiro, Kawasaki, Haruhiko
• Granted Patent: US 8,510,000 B2
• Time in Patent Office: Days
• US Class Current: 701/50
• CPC Class Codes: E02F 9/2075 of the hybrid type for vehicles in general B60W20/00
• CPC Class Codes: E02F 9/2228 including an electronic controller
• CPC Class Codes: E02F 9/2235 including an electronic controller
• CPC Class Codes: E02F 9/226 Safety arrangements, e.g. hydraulic driven fans, preventing cavitation, leakage, overheating
• 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: F02D 29/04 peculiar to engines driving pumps
• CPC Class Codes: F15B 11/024 by means of differential connection of the servomotor lines, e.g. regenerative circuits
• CPC Class Codes: F15B 21/14 Energy-recuperation means
• CPC Class Codes: F15B 2211/40515 with variable throttles or orifices
• CPC Class Codes: F15B 2211/411 the positions being discrete
• CPC Class Codes: F15B 2211/41545 being connected to multiple output members
• CPC Class Codes: F15B 2211/7051 Linear 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
• CPC Class Codes: F15B 2211/761 Control of a negative load, i.e. of a load generating hydraulic energy
• CPC Class Codes: F15B 2211/763 Control of torque of the output member by means of a variable capacity motor, i.e. by a secondary control on the motor
• CPC Class Codes: F15B 2211/88 Control measures for saving energy

Abstract

Effective use of energy is provided by recovering energy produced during braking in operation of a rotation motor RM alone for electric generation. A control unit C has functions: of operating a passage-resistance control unit (51) to reduce the passage resistance by a pressure relief valve 50 when determining based on a detection signal from a neutral-condition detecting unit (6, 8, 9, 11 and 16, 18, 19, 21) that all the operated valves 1-5, 12-15 in the circuit system are in the neutral position and a pressure signal from a brake-pressure-detection processor sensor 49 reaches a preset pressure; of causing a tilt-angle control unit 36 to control the tilt angle of a hydraulic motor HM; and of relatively controlling the passage resistance maintained by controlling the passage resistance control unit and the tilt angle of the hydraulic motor to maintain a brake pressure of the rotation motor.

Claims

1. A controller of a hybrid construction machine, including

a variable displacement type of a main pump,

a circuit system connected to the main pump and including a plurality of operated valves for controlling a plurality of actuators including a rotation motor, and

a neutral-condition detecting unit that detects whether or not all the operated valves provided in the circuit system are in a neutral position, comprising:

a variable displacement type of a hydraulic motor, a tilt angle of which is controlled by a tilt-angle control unit;

a generator linked to the hydraulic motor;

a hydraulic-motor system passage connected to a pair of passages connected to the rotation motor;

a brake-pressure-detection pressure sensor that is provided in the hydraulic-motor system passage and detects a brake pressure of the rotation motor;

a pressure relief valve provided in the hydraulic-motor system passage;

a passage resistance control unit that performs control for reducing a passage resistance caused by the pressure relief valve; and

a control unit connected to the tilt-angle control unit, the neutral-condition detecting unit, the brake-pressure-detection pressure sensor and the passage resistance control unit,

wherein the control unit comprises

a function of operating the passage-resistance control unit to reduce the passage resistance caused by the pressure relief valve when the control unit determines based on a detection signal received from the neutral-condition detecting unit that all the operated valves in the circuit system are in the neutral position and a pressure signal from the brake-pressure-detection processor sensor is indicative of a pressure reaching a preset pressure,

a function of causing the tilt-angle control unit to control the tilt angle of the hydraulic motor, and

a function of relatively controlling both the passage resistance maintained by controlling the passage resistance control unit and the tilt angle of the hydraulic motor to maintain a brake pressure of the rotation motor.

3. The controller of a hybrid construction machine according to claim 1,

wherein the neutral-condition detecting unit comprises

a pilot pressure generating mechanism that is provided in a neutral flow passage in the circuit system and generates a maximum pressure when all the operated valves provided in the circuit system are in the neutral position and a flow rate of a flow in the neutral flow passage is maximum,

a pilot flow passage guiding the pressure of the pilot pressure generating mechanism to the regulator provided in the main pump, and

a pilot-pressure-detection pressure sensor provided in the pilot flow passage and applying a detection signal to the control unit, and

the control unit comprises a function of determining, based on the detection signal received from the pilot-pressure-detection pressure sensor, that all the operated valves provided in the circuit system are in the neutral position.

4. The controller of a hybrid construction machine according to claim 1, comprising

an electric motor also serving as a generator, rotating coaxially with the hydraulic motor, and maintaining a free rotation state or outputting power in response to a control signal from the control unit,

a variable displacement type of a sub pump rotating coaxially with the hydraulic motor,

a tilt angel control unit controlling a tilt angle of the sub pump in response to a signal from the control unit, and

a merging passage for directing discharge fluid of the sub pump to a discharge side of the main pump,

wherein the control unit comprises a function of operating the tilt-angle control unit to change the tilt angle of the sub pump when the control unit determines based on a detection signal received from the neutral-condition detecting unit that all the operated valves in the circuit system are in the neutral position.

6. The controller of a hybrid construction machine according to claim 3, comprising

an electric motor also serving as a generator, rotating coaxially with the hydraulic motor, and maintaining a free rotation state or outputting power in response to a control signal from the control unit,

a variable displacement type of a sub pump rotating coaxially with the hydraulic motor,

a tilt angel control unit controlling a tilt angle of the sub pump in response to a signal from the control unit, and

a merging passage for directing discharge fluid of the sub pump to a discharge side of the main pump,

wherein the control unit comprises a function of operating the tilt-angle control unit to change the tilt angle of the sub pump when the control unit determines based on a detection, signal received from the neutral-condition detecting unit that all the operated valves in the circuit system are in the neutral position.

7. The controller of a hybrid construction machine according to claim 1, wherein the passage resistance control unit includes a proportional solenoid throttling valve provided in parallel to the pressure relief valve, and a degree of opening of the proportional solenoid throttling valve is controlled by a control signal of the control unit.

8. The controller of a hybrid construction machine according to claim 3, wherein the passage resistance control unit includes a proportional solenoid throttling valve provided in parallel to the pressure relief valve, and a degree of opening of the proportional solenoid throttling valve is controlled by a control signal of the control unit.

9. The controller of a hybrid construction machine according to claim 4, wherein the passage resistance control unit includes a proportional solenoid throttling valve provided in parallel to the pressure relief valve, and a degree of opening of the proportional solenoid throttling valve is controlled by a control signal of the control unit.

10. The controller of a hybrid construction machine according to claim 6, wherein the passage resistance control unit includes a proportional solenoid throttling valve provided in parallel to the pressure relief valve, and a degree of opening of the proportional solenoid throttling valve is controlled by a control signal of the control unit.

11. The controller of a hybrid construction machine according to claim 1, wherein

the passage resistance control unit includes the pressure relief valve as an essential element, and

the pressure relief valve includes a main pilot pressure chamber for guiding a pressure upstream of the pressure relief valve, and a sub pilot pressure chamber for guiding a pilot pressure controlled by the control unit which are provided at one end of the pressure relief valve, and also includes a spring provided at the other end facing an acting force of a pilot pressure in both the pilot pressure chambers.

12. The controller of a hybrid construction machine according to claim 3, wherein

the passage resistance control unit includes the pressure relief valve as an essential element, and

the pressure relief valve includes a main pilot pressure chamber for guiding a pressure upstream of the pressure relief valve, and a sub pilot pressure chamber for guiding a pilot pressure controlled by the control unit which are provided at one end of the pressure relief valve, and also includes a spring provided at the other end facing an acting force of a pilot pressure in both the pilot pressure chambers.

13. The controller of a hybrid construction machine according to claim 4, wherein

the passage resistance control unit includes the pressure relief valve as an essential element, and

the pressure relief valve includes a main pilot pressure chamber for guiding a pressure upstream of the pressure relief valve, and a sub pilot pressure chamber for guiding a pilot pressure controlled by the control unit which are provided at one end of the pressure relief valve, and also includes a spring provided at the other end facing an acting force of a pilot pressure in both the pilot pressure chambers.

14. The controller of a hybrid construction machine according to claim 6, wherein

the passage resistance control unit includes the pressure relief valve as an essential element, and

the pressure relief valve includes a main pilot pressure chamber for guiding a pressure upstream of the pressure relief valve, and a sub pilot pressure chamber for guiding a pilot pressure controlled by the control unit which are provided at one end of the pressure relief valve, and also includes a spring provided at the other end facing an acting force of a pilot pressure in both the pilot pressure chambers.

15. The controller of a hybrid construction machine according to claim 1, wherein

the passage resistance control unit includes a pressure relief valve and a solenoid on/off valve that opens/closes in response to a control signal from the control unit,

the pressure relief valve includes a main pilot pressure chamber provided at one end of the pressure relief valve for guiding a pressure upstream of the pressure relief valve, and also includes a spring and a sub pilot pressure chamber for guiding a pressure upstream of the pressure relief valve by way of a throttle which are provided at the other end of the pressure relief valve facing an acting force of a pilot pressure in the main pilot pressure chamber,

the solenoid on/off valve blocks a communication between the sub pilot pressure chamber and a tank when it is in a closed position, and allows a communication between the sub pilot pressure chamber and the tank when it is in an open position.

16. The controller of a hybrid construction machine according to claim 3, wherein

the passage resistance control unit includes a pressure relief valve and a solenoid on/off valve that opens/closes in response to a control signal from the control unit,

the pressure relief valve includes a main pilot pressure chamber provided at one end of the pressure relief valve for guiding a pressure upstream of the pressure relief valve, and also includes a spring and a sub pilot pressure chamber for guiding a pressure upstream of the pressure relief valve by way of a throttle which are provided at the other end of the pressure relief valve facing an acting force of a pilot pressure in the main pilot pressure chamber,

the solenoid on/off valve blocks a communication between the sub pilot pressure chamber and a tank when it is in a closed position, and allows a communication between the sub pilot pressure chamber and the tank when it is in an open position.

17. The controller of a hybrid construction machine according to claim 4, wherein

the passage resistance control unit includes a pressure relief valve and a solenoid on/off valve that opens/closes in response to a control signal from the control unit,

the pressure relief valve includes a main pilot pressure chamber provided at one end of the pressure relief valve for guiding a pressure upstream of the pressure relief valve, and also includes a spring and a sub pilot pressure chamber for guiding a pressure upstream of the pressure relief valve by way of a throttle which are provided at the other end of the pressure relief valve facing an acting force of a pilot pressure in the main pilot pressure chamber,

the solenoid on/off valve blocks a communication between the sub pilot pressure chamber and a tank when it is in a closed position, and allows a communication between the sub pilot pressure chamber and the tank when it is in an open position.

18. The controller of a hybrid construction machine according to claim 6, wherein

the passage resistance control unit includes a pressure relief valve and a solenoid on/off valve that opens/closes in response to a control signal from the control unit,

the pressure relief valve includes a main pilot pressure chamber provided at one end of the pressure relief valve for guiding a pressure upstream of the pressure relief valve, and also includes a spring and a sub pilot pressure chamber for guiding a pressure upstream of the pressure relief valve by way of a throttle which are provided at the other end of the pressure relief valve facing an acting force of a pilot pressure in the main pilot pressure chamber,

the solenoid on/off valve blocks a communication between the sub pilot pressure chamber and a tank when it is in a closed position, and allows a communication between the sub pilot pressure chamber and the tank when it is in an open position.

2. A controller of a hybrid construction machine, comprising:

a variable displacement type of a main pump;

a regulator for controlling a tilt angle of the main pump;

a plurality of operated valves connected to the main pump;

a rotation-motor operated valve connected to the main pump;

a rotation motor connected through a pair of passages to the rotation-motor operated valve;

a brake valve provided between the passages for the rotation motor;

a variable displacement type of a sub pump connected to a discharge side of the main pump and having a tilt angle controlled by a tilt-angle control unit;

a variable displacement type of a hydraulic motor having a tilt angle controlled by a tilt-angle control unit;

an electric motor also serving as a generator and integrally rotating the sub pump and the hydraulic motor;

a leading passage into which the pair of the passages for the rotation motor are merged;

a passage connecting the leading passage to the hydraulic motor;

a check valve provided in a stage of merging the passages for the rotation motor with the leading passage and permitting only passage of flows from the passages for the rotation motor to the leading passage;

a solenoid directional control valve for opening/closing the leading passage;

a pressure sensor provided between the solenoid directional control valve and the check valves;

a pressure relief valve provided in the leading passage between the solenoid directional control valve and the hydraulic motor; and

a control unit receiving a pressure signal from the pressure sensor and exercising a control function,

wherein the control unit controls the regulator of the main pump, the tilt-angle control unit of the sub pump, the tilt-angle control unit of the hydraulic motor and the electric motor on the basis of operational signals of the rotation motor and the other actuators,

controls opening/closing of the solenoid directional control valve in accordance with a signal received from the pressure sensor, and

opens the solenoid on/off valve to direct pressure fluid in the passages for the rotation motor from the leading passage through the pressure relief valve to the hydraulic motor, and uses a drive force of the hydraulic motor to assist output of the electric motor, when receiving a pressure signal indicative of a pressure lower than but close to a turning pressure of rotation motor from the pressure sensor.

5. The controller of a hybrid construction machine according to claim 2, comprising

an electric motor also serving as a generator, rotating coaxially with the hydraulic motor, and maintaining a free rotation state or outputting power in response to a control signal from the control unit,

a variable displacement type of a sub pump rotating coaxially with the hydraulic motor,

a tilt angel control unit controlling a tilt angle of the sub pump in response to a signal from the control unit, and

a merging passage for directing discharge fluid of the sub pump to a discharge side of the main pump,

wherein the control unit comprises a function of operating the tilt-angle control unit to change the tilt angle of the sub pump when the control unit determines based on a detection signal received from the neutral-condition detecting unit that all the operated valves in the circuit system are in the neutral position.