Control system for hybrid construction machine

Patent metadata

Field	Value
Publication number	US-9920502-B2
Application number	US-201414915654-A
Country	US
Kind code	B2
Filing date	Sep 11, 2014
Priority date	Sep 27, 2013
Publication date	Mar 20, 2018
Grant date	Mar 20, 2018

Abstract

A control system for hybrid construction machine includes a regeneration motor configured to be rotated by working fluid introduced from a turning circuit, a pressure detector configured to detect a turning pressure during a turning operation of the turning motor or a braking pressure during a braking operation of the turning motor, a switching valve for turning regeneration configured to perform turning regeneration by introducing the working fluid from the turning circuit to the regeneration motor when being switched to an open position by a pressure of pilot fluid, an electromagnetic proportional pressure reducing valve configured to be switched to an open position and generate a pilot secondary pressure for switching the switching valve for turning regeneration to the open position when a pressure detected by the pressure detector reaches a first set pressure, and a pilot switching valve configured to allow the passage of the pilot fluid for switching the switching valve for turning regeneration to the open position by being switched to an open position when the pressure of the turning circuit reaches a second set pressure.

First claim

The invention claimed is:

1. A control system for hybrid construction machine, comprising:
a fluid pressure pump which is a drive source of a turning motor;
a regeneration motor for regeneration configured to be rotated by working fluid introduced from a turning circuit for driving the turning motor;
a rotating electric machine which is coupled to the regeneration motor;
a pressure detector configured to detect a turning pressure during a turning operation of the turning motor or a braking pressure during a braking operation of the turning motor;
a controller configured to execute a regeneration control of the hybrid construction machine;
a switching valve for turning regeneration configured to be switched by a pressure of supplied pilot fluid and perform turning regeneration by introducing the working fluid from the turning circuit to the regeneration motor when being switched to an open position;
an electromagnetic proportional pressure reducing valve configured to be switched to an open position in response to a command from the controller and generate a pilot secondary pressure for switching the switching valve for turning regeneration to the open position when a pressure detected by the pressure detector reaches a first set pressure set in advance; and
a pilot switching valve configured to be provided in series with the electromagnetic proportional pressure reducing valve and allow the passage of the pilot fluid for switching the switching valve for turning regeneration to the open position by being switched to an open position using a pressure of the turning circuit as a pilot pressure when the pressure of the turning circuit reaches a second set pressure set in advance.

2. The control system for hybrid construction machine according to claim 1 , wherein:
the first set pressure is set at a turning regeneration starting pressure at which the turning regeneration is started; and
the second set pressure is set lower than the first set pressure.

3. The control system for hybrid construction machine according to claim 1 , wherein:
the pilot switching valve is arranged between the electromagnetic proportional pressure reducing valve and the switching valve for turning regeneration.

4. The control system for hybrid construction machine according to claim 1 , wherein:
the switching valve for turning regeneration is switched by a pressure of the pilot fluid introduced from a pilot pump.

5. The control system for hybrid construction machine according to claim 1 , wherein:
the switching valve for turning regeneration is switched by the pressure of the turning circuit for switching the pilot switching valve to the open position.

6. The control system for hybrid construction machine according to claim 1 , further comprising:
a turning regeneration passage in which the switching valve for turning regeneration is provided;
a pressure reducing valve which is provided on a side downstream of the switching valve for turning regeneration in the turning regeneration passage;
a bypass passage which is connected to the turning regeneration passage and bypasses the pressure reducing valve; and
a bypass valve which is provided in the bypass passage and has a shut-off position and a communication position.

7. The control system for hybrid construction machine according to claim 6 , further comprising:
a fluid pressure cylinder configured to be driven by the fluid pressure pump;
an operating state detector configured to detect an operating state of the fluid pressure cylinder;
a switching valve for cylinder regeneration configured to be provided in parallel to the switching valve for turning regeneration, opened based on a detection result of the operating state detector and performs cylinder regeneration by introducing the working fluid from the fluid pressure cylinder to the regeneration motor;
a cylinder regeneration passage in which the switching valve for cylinder regeneration is provided; and
a joint regeneration passage to which the turning regeneration passage and the cylinder regeneration passage are joined and connected and which introduces the working fluid to the regeneration motor.

8. The control system for hybrid construction machine according to claim 7 , wherein:
the regeneration motor is rotated by the working fluid introduced from the turning circuit for driving the turning motor and the working fluid introduced from the fluid pressure cylinder; and
the bypass valve is set to the communication position when only the turning regeneration is performed while being set to the shut-off position when the turning regeneration and the cylinder regeneration are simultaneously performed.

9. The control system for hybrid construction machine according to claim 8 , wherein:
the regeneration motor is a variable displacement motor capable of adjusting a tilt angle of a swash plate; and
the controller is configured to control the tilt angle of the swash plate and a rotating speed of the regeneration motor so that the pressure detected by the pressure detector does not fall below the first set pressure when only the turning regeneration is performed.

10. The control system for hybrid construction machine according to claim 7 , wherein:
the switching valve for turning regeneration is set to a shut-off position when the pressure detected by the pressure detector is below the first set pressure, set to a first communication position for opening the bypass passage when the pressure detected by the pressure detector reaches the first set pressure and the switching valve for cylinder regeneration is closed, and set to a second communication position for opening the turning regeneration passage and shutting off the bypass passage when the pressure detected by the pressure detector reaches the first set pressure and the switching valve for cylinder regeneration is in a valve-opened state.

11. The control system for hybrid construction machine according to claim 7 , wherein:
the switching valve for turning regeneration is set to a shut-off position when the pressure detected by the pressure detector is below the first set pressure, set to a first communication position for introducing the working fluid from the turning circuit to the regeneration motor without reducing the pressure of the working fluid when the pressure detected by the pressure detector reaches the first set pressure and the switching valve for cylinder regeneration is closed, and set to a second communication position for throttling and introducing the working fluid from the turning circuit to the regeneration motor when the pressure detected by the pressure detector reaches the first set pressure and the switching valve for cylinder regeneration is in a valve-opened state.

12. The control system for hybrid construction machine according to claim 1 , further comprising:
a relief valve configured to allow the flow of the working fluid toward a low-pressure side by being opened when the turning pressure during the turning operation of the turning motor or the braking pressure during the braking operation of the turning motor reaches a set pressure; and
an adjuster configured to adjust the set pressure of the relief valve;
wherein the adjuster is configured to increase the set pressure of the relief valve from an initial set pressure when a pressure detected by the pressure detector reaches the first set pressure.

Assignees

• Kyb Corp

Inventors

• Kawasaki Haruhiko
• Egawa Masahiro

Classifications

• E02F9/2267

  Valves or distributors (position of valves arrangements on upper-structures E02F9/0875) · CPC title

• E02F9/2285

  Pilot-operated systems · CPC title

• F15B2211/6313

  the pressure being a load pressure · CPC title

• E02F9/2075

  of the hybrid type (for vehicles in general B60W20/00) · CPC title

• E02F9/2217

  with energy recovery arrangements, e.g. using accumulators, flywheels · CPC title