Komatsu Corporation

Kazuhiro Maruta

Nobumi Yoshida

Hiroshi Endo

Teruo Akiyama

Naoki Ishizaki

Masashi Ichihara

Jin Kitajima

Hisashi Asada

Shinobu Nagura

Takeshi Ooi

Mutsumi Ono

Takahiro Miyata

Kenichi Ogasawara

Katsuji Ishikawa

A method of suppressing a pulsation of axial type hydraulic pump/motor includes performing a pressure accumulation operation in which each of ports of each of two pressure accumulation oil passages exclusively communicates with a corresponding one of communication holes and pressure inside one of the cylinder bores is accumulated in a corresponding one of the pressure accumulation oil passages through the communication hole in two levels, the communication holes being provided for each of the cylinder bores to communicate with inside of each of the cylinder bores and having opening portions sliding on the respective ports with rotation of the cylinder block to communicate with the respective ports; and performing an accumulated pressure collection operation in which the pressure accumulated in the pressure accumulation oil passage is collected in one of the cylinder bores in two levels.

Hydraulic pump/motor and method of suppressing pulsation of hydraulic pump/motor

The system includes: a variable displacement hydraulic pump supplying pressure oil to a hydraulic actuator; a pressure detector detecting a pump discharge pressure from the hydraulic pump; a control valve controlling a supply of the pressure oil to the hydraulic actuator; a controller controlling a pump displacement of the hydraulic pump; a hydraulic motor rotating an upper structure of the construction machine; a swing relief valve defining a relief pressure of the hydraulic motor; and a control lever switching a control valve for the hydraulic motor. The controller includes: an adjuster that, when a pump discharge pressure detected by the pressure detector exceeds a first set value, conducts an adjustment to reduce the pump displacement; and a canceller that cancels the adjustment when the pump discharge pressure falls below a second set value. The second set value is equal to or larger than the first set value.

Swing drive controlling system for construction machine

A hydraulic motorof the invention includes a detected unitformed on an outer circumferential surface of a cylinder blockand a rotation sensorarranged opposed to the detected unitfor detecting the detected unit. The rotation sensoris provided on a position corresponding to a position between a deepest portionof a cylinder holeand a rear end faceof the cylinder block in an axial direction of the cylinder block. A fan driving deviceis provided with the hydraulic motor, a bracketto which the hydraulic motor is attached in a state in which a tip end of the rotational shaftis arranged on a surface side thereof through a through-holeand a fanattached to the rotational shaftand is driven by the hydraulic motor.

Hydraulic pump/motor and fan driving device

An arrangement structure of a swash plate hydraulic pump which can be used in a wide range of construction equipment and industrial vehicles and is small in size, simple in structure, and inexpensive is provided. For this purpose, an arrangement structure of a swash plate hydraulic pump () comprises a driving source () and a plurality of swash plate hydraulic pumps () which are connected to the driving source and discharge pressurized oil, and the plurality of swash plate hydraulic pumps include at least one swash plate hydraulic pump () of the second and subsequent swash plate hydraulic pumps which has a driving shaft () provided on a plane almost perpendicular to a driving shaft () of the first swash plate hydraulic pump () coupled to the driving source.

Arrangement structure of swash plate hydraulic pump hydraulic pump

It is an object of the present invention to provide a plural pressure oil energies selective recovery apparatus which can selectively recover pressure oil energies stored in plural pressure oil actuators, based upon recovery conditions. A priority for recovering a return pressure oil from a hydraulic actuator is set in advance for an operation lever of each of the plural hydraulic actuators. If the operation lever is in the non-actuation state at a preceding detection point, the plural pressure oil energies selective recovery apparatus recovers a return pressure oil from a corresponding hydraulic actuator. If the operation lever is in the actuation state, the plural pressure oil energies selective recovery apparatus does not recover a pressure oil.

Plural pressure oil energies selective recovery apparatus and selective recovery method therefor

A balance of force acting on a pool of a control valve is expressed by (P &minus;P )&middot;A&equals;F&plus;f When it is assumed that a pressure difference P &minus;P before and after a throttle is &Dgr;P to modify the above expression, an expression &Dgr;P &middot;A&plus;(P &minus;P )&middot;A&equals;f&plus;F is obtained. According to the present invention, the force &Dgr;P &middot;A corresponding to the pressure difference &Dgr;P before and after the second throttle of the first term of the left-hand side is applied to the control valve as a force capable of canceling the flow force f at the first term of the right-hand side.

Hydraulic drive unit

A pressure oil energy recovery apparatus or pressure oil energy recovery/regeneration apparatus that does not require much room and can be mounted within a narrow space, capable of broadening the range of applications for recovered energy. A hydraulic pump motor is actuated by the inflow of the return pressure oil flowing out of a hydraulic actuator. The drive force of the hydraulic pump motor is input to allow an electric motor to generate electric energy. The electric energy generated by the electric motor is stored in a battery. When the energy of pressure oil is regenerated, the energy expended during the actuation of the hydraulic actuator by the hydraulic pump is supplemented with the electric energy stored in the battery.

Pressure oil energy recover/regenation apparatus

A target fan rotational speed (R.P.M.) corresponding to a temperature detected by a temperature detector is determined according to a set correlation and the capacity of a variable-capacity hydraulic pump is varied so that the rotational speed of a cooling fan becomes that determined target fan rotational speed. It thereby becomes possible to precisely control the blowing air volume (R.P.M.) of the cooling fan, and, when the cooling fan is driven with a hydraulic source, to construct a hydraulic circuit with fewer parts. Moreover, in cases where the torque absorbed by the fan-drive hydraulic motor fluctuates, control is effected to suppress fluctuations in the cooling fan rotational speed and stabilize the rotation. Furthermore, in cases where the load on the fan-drive hydraulic motor fluctuates, control is effected to suppress fluctuations in the cooling fan rotational speed and stabilize the rotation.

Cooling fan drive apparatus

Air blower apparatus (,) in which a fan boss (,) at the rotational center portion of a fan (,) has a recessed form. Meanwhile, the central part of the body portion (,) of the air blower apparatus (,), i.e., a boss portion (,), has a projecting form to be housed within the recessed fan boss (,). The central part of the body potion (,), i.e., the boss portion (,), is housed within the recessed fan boss (,) at the rotational center portion of the fan (,), and the rotary shaft (,) of the body portion (,) of the air blower apparatus (,) is mounted on the fan (,).

Air blower apparatus

The present invention has an object to enable to supply a discharged pressurized fluid of a hydraulic pump without any energy loss with an arbitrary flow rate distribution ratio to a plurality of actuators. A discharged pressurized fluid of the hydraulic pump,is supplied to the first and second actuators,and,via the first and second variable displacement type hydraulic pump/motors,and,The first variable displacement type hydraulic pump/motor,and the second variable displacement type hydraulic pump/motor,are mechanically connected to rotate at the same revolution speed. By this, the pressurized fluid is supplied to the first and second actuators,and,depending upon displacements of the first and second variable displacement type hydraulic pump/motors.

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Kawaguchi, Japan

Kazuhiro Maruta