Construction machine

Patent metadata

Field	Value
Publication number	US-10526767-B2
Application number	US-201515556103-A
Country	US
Kind code	B2
Filing date	Sep 29, 2015
Priority date	Sep 29, 2015
Publication date	Jan 7, 2020
Grant date	Jan 7, 2020

Abstract

The construction machine includes: a first hydraulic actuator; a second hydraulic actuator; a tank; and a first hydraulic pump supplying a hydraulic fluid to the second hydraulic actuator, the construction machine further including: a return hydraulic fluid selection device selecting a supply source of a return hydraulic fluid generated at a time of a raising operation or a lowering operation of the first hydraulic actuator and discharging the return hydraulic fluid; a regeneration line supplying the hydraulic fluid discharged from the return hydraulic fluid selection device to a portion between the second hydraulic actuator and the first hydraulic pump to regenerate the hydraulic fluid; a discharge line discharging the hydraulic fluid discharged from the return hydraulic fluid selection device to the tank; and a regeneration/discharge flow rate adjustment device capable of adjusting a flow rate of the hydraulic fluid flowing through the regeneration line and a flow rate of the hydraulic fluid flowing through the discharge line.

First claim

The invention claimed is:

1. A construction machine comprising:
a first hydraulic actuator that is a hydraulic cylinder;
a second hydraulic actuator; a tank; and
a first hydraulic pump supplying a hydraulic fluid to the second hydraulic actuator, the construction machine further comprising:
a return hydraulic fluid selection device that is connected to a bottom side hydraulic fluid chamber and a rod side hydraulic fluid chamber of the first hydraulic actuator via hydraulic lines, selects the rod side hydraulic fluid chamber as a supply source of a return hydraulic fluid at a time of a raising operation of the first hydraulic actuator, and selects the bottom side hydraulic fluid chamber as the supply source of the return hydraulic fluid at a time of a lowering operation of the first hydraulic actuator;
a regeneration line supplying the hydraulic fluid discharged from the return hydraulic fluid selection device to a portion between the second hydraulic actuator and the first hydraulic pump to regenerate the hydraulic fluid;
a discharge line discharging the hydraulic fluid discharged from the return hydraulic fluid selection device to the tank;
a regeneration/discharge flow rate adjustment device capable of adjusting a flow rate of the hydraulic fluid flowing through the regeneration line and a flow rate of the hydraulic fluid flowing through the discharge line; and
a first operation device for operating the first hydraulic actuator in a raising direction or a lowering direction; a second operation device for operating the second hydraulic actuator; a first operation amount sensor capable of detecting an operation amount of the first operation device; and a second operation amount sensor capable of detecting an operation amount of the second operation device, wherein
the return hydraulic fluid selection device controls the supply source and the discharge flow rate of the return hydraulic fluid in accordance with the operation amount of the first operation device; and
the regeneration/discharge flow rate adjustment device controls the flow rate of the hydraulic fluid flowing through the regeneration line and the flow rate of the hydraulic fluid flowing through the discharge line in accordance with the respective operation amounts detected by the first operation amount sensor and the second operation amount sensor.

2. The construction machine according to claim 1 , wherein
the first operation device is a hydraulic pilot type operation device;
the regeneration/discharge flow rate adjustment device has a regeneration control valve capable of diverting or switching the hydraulic fluid discharged from the return hydraulic fluid selection device to the regeneration line and the discharge line, and a discharge valve provided on a downstream side of the regeneration control valve and capable of adjusting the flow rate of the hydraulic fluid discharged to the tank by a pilot pressure outputted from the first operation device; and
the construction machine further comprises a controller that inputs the respective operation amount signals detected by the first operation amount sensor and the second operation amount sensor, and controls an opening degree of the regeneration control valve in accordance with these signals.

3. The construction machine according to claim 2 , further comprising:
a first pressure sensor detecting a pressure of the return hydraulic fluid at the time of the lowering operation of the first hydraulic actuator; and
a second pressure sensor detecting a pressure between the first hydraulic pump and the second hydraulic actuator, wherein
the controller inputs a pressure signal of the return hydraulic fluid at the time of the lowering operation of the first hydraulic actuator detected by the first pressure sensor and a pressure signal between the first hydraulic pump and the second hydraulic actuator detected by the second pressure sensor, and controls the opening degree of the regeneration control valve in accordance with these signals.

4. The construction machine according to claim 2 , further comprising:
a second hydraulic pump, wherein
the discharge valve is provided with a hydraulic line for supplying the hydraulic fluid delivered from at least one of the first hydraulic pump and the second hydraulic pump to the first hydraulic actuator at the time of the raising operation of the first hydraulic actuator or the lowering operation thereof.

5. The construction machine according to claim 1 , wherein
the regeneration/discharge flow rate adjustment device has a regeneration valve regenerating the hydraulic fluid discharged from the return hydraulic fluid selection device in the regeneration line, and a discharge valve discharging the hydraulic fluid discharged from the return hydraulic fluid selection device to the tank; and
the construction machine further comprises a controller that inputs the respective operation amount signals detected by the first operation amount sensor and the second operation amount sensor, and controls the opening degree of the regeneration valve and the opening degree of the discharge valve in accordance with these signals.

6. The construction machine according to claim 5 , further comprising:
a first pressure sensor detecting a pressure of the return hydraulic fluid at the time of the lowering operation of the first hydraulic actuator; and
a second pressure sensor detecting a pressure between the first hydraulic pump and the second hydraulic actuator, wherein
the controller inputs a pressure signal of the return hydraulic fluid at the time of the lowering operation of the first hydraulic actuator detected by the first pressure sensor and a pressure signal between the first hydraulic pump and the second hydraulic actuator detected by the second pressure sensor, and controls the opening degree of the regeneration valve and the opening degree of the discharge valve in accordance with these signals.

7. The construction machine according to claim 1 , further comprising:
a second hydraulic pump, wherein
the return hydraulic fluid selection device is provided with a hydraulic line for supplying the hydraulic fluid delivered from at least one of the first hydraulic pump and the second hydraulic pump to the first hydraulic actuator at the time of the raising operation of the first hydraulic actuator or the lowering operation thereof.

8. A construction machine comprising:
a first hydraulic actuator that is a hydraulic cylinder;
a second hydraulic actuator; a tank; and
a first hydraulic pump supplying a hydraulic fluid to the second hydraulic actuator, the construction machine further comprising:
a return hydraulic fluid selection device that is connected to a bottom side hydraulic fluid chamber and a rod side hydraulic fluid chamber of the first hydraulic actuator via hydraulic lines, selects the rod side hydraulic fluid chamber as a supply source of a return hydraulic fluid at a time of a raising operation of the first hydraulic actuator, and selects the bottom side hydraulic fluid chamber as the supply source of the return hydraulic fluid at a time of a lowering operation of the first hydraulic actuator;
a regeneration line supplying the hydraulic fluid discharged from the return hydraulic fluid selection device to a portion between the second hydraulic actuator and the first hydraulic pump to regenerate the hydraulic fluid;
a discharge line discharging the hydraulic fluid discharged from the return hydraulic fluid selection device to the tank;
a regeneration/discharge flow rate adjustment device capable of adjusting a flow rate of the hydraulic fluid flowing through the regeneration line and a flow rate of the hydraulic fluid flowing through the discharge line;
a hydraulic pilot type first operatio

Assignees

• Hitachi Construction Mach Co

Inventors

• Hijikata Seiji
• Ishikawa Kouji
• Imura Shinya

Classifications

• F15B11/024

  by means of differential connection of the servomotor lines, e.g. regenerative circuits · CPC title

• F15B21/14

  Energy-recuperation means · CPC title

• F15B2211/5156

  being connected to a return line and a directional control valve · CPC title

• E02F9/2271

  Actuators and supports therefor and protection therefor · CPC title

• E02F9/2296

  Systems with a variable displacement pump · CPC title