# US 11,111,651 B2 · Construction machine

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- Number: US 11,111,651 B2
- Document ID: US11111651B2
- Status: Granted
- Kind: B2
- Application number: 17/054,869
- Filed: 2019-05-20
- Published: 2021-07-29
- Granted: 2021-09-07
- Earliest claimed: 2018-06-26
- Assignees: Hitachi Construction Machinery Co., Ltd.
- Applicants: Hitachi Construction Machinery Co., Ltd.
- Inventors: Juri Shimizu; Kenji Hiraku; Hiromasa Takahashi; Teppei Saitou
- Web page: https://patentgrep.com/patent/US11111651B2

## CPC

- E02F 9/2242: {including an electronic controller}
- E02F 9/2296: {Systems with a variable displacement pump}
- E02F 3/32: working downwardly and towards the machine, e.g. with backhoes
- E02F 9/2228: {including an electronic controller}
- E02F 9/2235: {including an electronic controller}
- E02F 9/2246: {Control of prime movers, e.g. depending on the hydraulic load of work tools}
- E02F 9/2267: {Valves or distributors (position of valves arrangements on upper-structures E02F9/0875)}
- E02F 9/2289: {Closed circuit}
- E02F 9/2292: {Systems with two or more pumps}
- F02D 25/00: Controlling two or more co-operating engines
- F02D 29/04: peculiar to engines driving pumps
- F15B 7/001: {With multiple inputs, e.g. for dual control}
- F15B 7/006: {Rotary pump input}
- F15B 7/008: {with rotary output}
- F15B 11/163: {for sharing the pump output equally amongst users or groups of users, e.g. using anti-saturation, pressure compensation}
- F15B 11/17: using two or more pumps
- F15B 21/087: {Control strategy, e.g. with block diagram}
- F15B 2211/20523: Internal combustion engine
- F15B 2211/20546: variable capacity
- F15B 2211/20561: reversible
- F15B 2211/20569: capable of working as pump and motor
- F15B 2211/20576: with multiple pumps
- F15B 2211/2656: by control of the pumps
- F15B 2211/27: Directional control by means of the pressure source
- F15B 2211/30565: having multiple valves for a single output member, e.g. for creating higher valve function by use of multiple valves like two 2/2-valves replacing a 5/3-valve
- F15B 2211/30595: with additional valves between the groups of valves for multiple output members
- F15B 2211/31535: having multiple pressure sources and a single output member
- F15B 2211/327: electrically or electronically
- F15B 2211/41572: being connected to a pressure source and an output member
- F15B 2211/50536: using unloading valves controlling the supply pressure by diverting fluid to the return line
- F15B 2211/526: electrically or electronically
- F15B 2211/6313: the pressure being a load pressure
- F15B 2211/633: representing a state of the prime mover, e.g. torque or rotational speed
- F15B 2211/6346: representing a state of input means, e.g. joystick position
- F15B 2211/6652: Control of the pressure source, e.g. control of the swash plate angle
- F15B 2211/6655: Power control, e.g. combined pressure and flow rate control
- F15B 2211/7135: Combinations of output members of different types, e.g. single-acting cylinders with rotary motors
- F15B 2211/7142: the output members being arranged in multiple groups
- E02F: DREDGING; SOIL-SHIFTING (winning peat E21C49/00)
- F02D: CONTROLLING COMBUSTION ENGINES (vehicle fittings, acting on a single sub-unit only, for automatically controlling vehicle speed B60K31/00; conjoint control of vehicle sub-units of different type or different function, road vehicle drive control systems for purposes other than the control of a single sub-unit B60W)
- F15B: SYSTEMS ACTING BY MEANS OF FLUIDS IN GENERAL; FLUID-PRESSURE ACTUATORS, e.g. SERVOMOTORS; DETAILS OF FLUID-PRESSURE SYSTEMS, NOT OTHERWISE PROVIDED FOR

## Abstract

An object of the present invention is to provide a construction machine that has a hydraulic closed-circuit system mounted therein and capable of selectively connecting some of a plurality of hydraulic pumps driven by two engines to any one of a plurality of hydraulic actuators and that can downsize the engines while maintaining high work efficiency. A controller 80 includes an actuator/engine allocation computing section F6 that, at the time of connecting closed-circuit pumps that are not connected to any of the hydraulic actuators 1, 3, 5, and 7 to any one of the hydraulic actuators, allocates closed-circuit pumps driven by a right engine 9b to the one hydraulic actuator in a case in which an estimated maximum load on a left engine 9a is heavier than an estimated maximum load on the right engine, and allocates closed-circuit pumps driven by the left engine to the one hydraulic actuator in a case in which the estimated maximum load on the right engine is heavier than the estimated maximum load on the left engine.

## Claims

### Claim 1

A construction machine comprising:
a first engine;
a second engine;
a plurality of bidirectionally variable displacement first hydraulic pumps driven by the first engine;
a plurality of bidirectionally variable displacement second hydraulic pumps driven by the second engine;
a plurality of hydraulic actuators;
an operation device for instructing operation amounts of the plurality of hydraulic actuators;
a plurality of selector valves selectively connecting the plurality of first hydraulic pumps and the plurality of second hydraulic pumps to any one of the plurality of hydraulic actuators; and
a controller controlling the plurality of first hydraulic pumps, the plurality of second hydraulic pumps, and the plurality of selector valves according to an input from the operation device, wherein
the controller includes
an engine load computing section that computes a total of estimated maximum demanded power of first hydraulic pumps connected to the plurality of hydraulic actuators among the plurality of first hydraulic pumps as an estimated maximum load on the first engine, and that computes a total of estimated maximum demanded power of second hydraulic pumps connected to any of the plurality of hydraulic actuators among the plurality of second hydraulic pumps as an estimated maximum load on the second engine,
an actuator/engine allocation computing section that, at a time of connecting first or second hydraulic pumps that are not connected to any of the plurality of hydraulic actuators among the plurality of first hydraulic pumps and the plurality of second hydraulic pumps to any one of the plurality of hydraulic actuators, allocates second hydraulic pumps that are not connected to any of the plurality of hydraulic actuators among the plurality of second hydraulic pumps to the one hydraulic actuator in a case in which the estimated maximum load on the first engine is heavier than the estimated maximum load on the second engine, and allocates first hydraulic pumps that are not connected to any of the plurality of hydraulic actuators among the plurality of first hydraulic pumps to the one hydraulic actuator in a case in which the estimated maximum load on the second engine is heavier than the estimated maximum load on the first engine, and
a command generation section that generates command signals to the plurality of first hydraulic pumps, the plurality of second hydraulic pumps, and the plurality of selector valves according to a computing result of the actuator/engine allocation computing section.

### Claim 2 (depends on 1)

The construction machine according to claim 1, comprising:
a pressure sensor that detects pressures of the plurality of actuators, wherein
the engine load computing section
computes the estimated maximum demanded power of the first hydraulic pumps by performing multiplication of a rated revolution speed of the first engine, a maximum delivery capacity of the first hydraulic pumps, and a differential pressure between estimated delivery pressures and estimated suction pressures of the first hydraulic pumps computed on a basis of the pressure of the hydraulic actuator to which the first hydraulic pumps are connected, and
computes the estimated maximum demanded power of the second hydraulic pumps by performing multiplication of a rated revolution speed of the second engine, a maximum tilting angle, and the pressure of the hydraulic actuator to which the second hydraulic pumps are connected.

### Claim 3 (depends on 1)

The construction machine according to claim 1, wherein
the actuator/engine allocation computing section
has a first actuator/engine allocation map that makes each of the plurality of hydraulic actuators correspond to the first or second engine, and
allocates the first or second hydraulic pumps driven by the first or second engine made to correspond to the one hydraulic actuator by the first actuator/engine allocation map to the one hydraulic actuator in a case of driving the one hydraulic actuator first.

### Claim 4 (depends on 3)

The construction machine according to claim 3, comprising:
a lower travel structure;
an upper swing structure swingably mounted onto the lower travel structure; and
a boom vertically rotatably attached to a front side of the upper swing structure, wherein
the plurality of hydraulic actuators include a swing motor that drives the upper swing structure and a boom cylinder that drives the boom, and
the first actuator/engine allocation map makes one of the first and second engines correspond to the boom cylinder, and the other of the first and second engines correspond to the swing motor.

### Claim 5 (depends on 3)

The construction machine according to claim 3, wherein
the actuator/engine allocation computing section
further has a second actuator/engine allocation map that makes the hydraulic actuators, having been made to correspond to the first engine by the first actuator/engine allocation map, correspond to the second engine, and that makes the hydraulic actuators, having been made to correspond to the second engine by the first actuator/engine allocation map, correspond to the first engine, and
uses the first actuator/engine allocation map and the second actuator/engine allocation map by changing over between the first actuator/engine allocation map and the second actuator/engine allocation map at predetermined timing.