Work machine

Patent metadata

Field	Value
Publication number	US-10370824-B2
Application number	US-201515122540-A
Country	US
Kind code	B2
Filing date	Mar 13, 2015
Priority date	May 30, 2014
Publication date	Aug 6, 2019
Grant date	Aug 6, 2019

Abstract

To provide a work machine which, in a configuration provided with a closed-circuit pump and an open-circuit pump, is capable of stabilizing respective pump operations of the closed-circuit pump and the open-circuit pump and of improving the mountability of the closed-circuit pump and the open-circuit pump. The present invention is provided with a closed circuit in which a closed-circuit pump and a boom cylinder are connected annularly, and an open circuit which has an open-circuit pump for making hydraulic fluid flow in from a reservoir and flow out and a connection passage capable of introducing hydraulic fluid into the closed circuit, wherein the closed-circuit pump is installed above the open-circuit pump.

First claim

The invention claimed is:

1. A work machine comprising:
an undercarriage provided with a travel device;
an upperstructure pivotally attached to the undercarriage;
a closed circuit provided with at least one closed-circuit hydraulic pump having two outlet/inlet ports each enabling the outlet and inlet of hydraulic fluid in both directions and a single-rod cylinder having a piston, a cap-end chamber into which the hydraulic fluid is introduced when the piston extends, and a rod-end chamber into which the hydraulic fluid is introduced when the piston retracts, the two outlet/inlet ports of the closed-circuit hydraulic pump being annularly connected with the cap-end chamber and the rod-end chamber;
an open circuit provided with an open-circuit hydraulic pump having an inlet port into which hydraulic fluid flows from a reservoir, and an outlet port from which hydraulic fluid flows out;
a connection circuit which introduces the hydraulic fluid flowing out from the open-circuit hydraulic pump into the closed circuit;
an engine; and
a power transmission device that includes four rotational shafts and transmits a rotational power of the engine to the closed-circuit hydraulic pump and the open-circuit hydraulic pump; wherein
the reservoir is mounted on a frame supporting the upperstructure;
the engine is mounted on the frame adjacent to the reservoir;
the closed-circuit hydraulic pump is connected to the two upper rotational shafts among the four rotational shafts; and
the open-circuit hydraulic pump is connected to the two lower rotational shafts among the four rotational shafts.

2. The work machine according to claim 1 , comprising:
a plurality of the open-circuit hydraulic pumps;
a first connection pipe connected to the reservoir; and
a plurality of second connection pipes connected to the first connection pipe at respective one ends and connected to inlet ports of the plurality of open-circuit hydraulic pumps at the respective other ends.

3. The work machine according to claim 1 , comprising:
a plurality of the open-circuit hydraulic pumps; and
a plurality of connection pipes connected to the reservoir at respective one ends and connected to the inlet ports of the plurality of open-circuit hydraulic pumps at the respective other ends.

Assignees

• Hitachi Construction Mach Co

Inventors

• Hiraku Kenji
• Takahashi Hiromasa

Classifications

• E02F9/22 Primary

  Hydraulic or pneumatic drives {(for dipper or bucket arm position control E02F3/43, for blade position control for graders E02F3/844; for turntables E02F9/121; for fork-lift trucks B66F9/22)} · CPC title

• E02F9/2264

  Arrangements or adaptations of elements for hydraulic drives · CPC title

• E02F3/32

  working downwardly and towards the machine, e.g. with backhoes · CPC title

• E02F9/2292

  Systems with two or more pumps · CPC title

• F15B2211/27

  Directional control by means of the pressure source · CPC title