Komatsu Corporation

Kabushiki Kaisha Komatsu Seisakusho

Nobumi Yoshida

Kazuhiro Maruta

Hiroshi Endo

Yukio Shoji

Tadao Karakama

Nobuhisa Honda

Yuichi Yamamoto

Naoki Ishizaki

Teruo Akiyama

Masato Kageyama

Shinobu Nagura

Yasuhiro Sato

Toyomi Kataoka

Kazuhiro Muruta

Ryoji Wakisaka

It is an object of the present invention to provide a filter for trapping foreign matter in which a filtration element can trap foreign matter that is admixed to a fluid present inside the filter with good reliability and a comparatively high trapping ratio. Hydraulic oil that has flown from an opening portion into a guide space of a first flow path guide is guided downward by the first flow path guide and directed toward a second flow path guide. As a result, the oil passes through a very narrow gap, that is, a gap with a cross sectional area of the flow path narrowed so as to increase the flow velocity of the hydraulic oil, a rising flow of the hydraulic oil is formed, and this flow is spouted up by the second flow path guide and guided by the first flow path guide toward a filter element. Foreign matter admixed to the hydraulic oil rises with good intensity together with the hydraulic oil and is moved by the hydraulic oil toward the filter element. Therefore, foreign matter can be trapped by the filter element with good reliability and a comparative high trapping ratio.

Filter for trapping foreign matter

A plurality of Hall ICsA,B are disposed around a magnetic rodthat is movable along a central axis. The Hall ICs are disposed in different positions in terms of both a straight line distance coordinate in the direction of the central axis and a rotational angle coordinate around the central axis. The amount of displacement of the magnetic rodis calculated based on the average of output signals from the Hall ICs. Errors in the output signals due to a shift and tilt of the magnetic rod are detected and calibration of the measurement method is carried out.

Displacement sensor

A disclosed device eliminates an error in a displacement amount measured value caused by changes over time in a characteristic of a displacement sensor, and can always maintain high accuracy of measurement. When a hydraulic valve, to which the displacement sensor is mounted, is positioned at predetermined positions, output signals from the displacement sensor are acquired as sample values. On the basis of the acquired sample values, a trend of changes over time in the characteristic of the displacement sensor is computed. Settings of a conversion table, which is used for displacement amount computation, are corrected in a direction along the computed trend of changes.

Displacement amount measuring device

In a hydraulic machine, hydraulic pump failure is detected and the pump lifespan is estimated before the pump failure occurs. The discharge pressure, oil temperature, and drain filter differential pressureare measured, a correlative relationshipbetween the filter differential pressure and the discharge pressure is determined, and a representative filter differential pressureis calculated from this correlative relationship. Using an oil temperature-differential pressure correlation function, the representative differential pressure valueis corrected so that the variable componentcaused by the oil temperatureis eliminated therefrom. The long-term trend and the short-term trend of the increase over time of the corrected differential pressure is calculated. A pump failure is predicted or the pump lifespan is estimated based on the degree of deviation between the long-term trend and the short-term trend.

Hydraulic machine, system for monitoring health of hydraulic machine, and method thereof

In a displacement sensor (), a shaft () of a movable member () comprises a tubular part () having an opening () at one end. A rod-form permanent is inserted into the tubular part () through the opening () . A spacer () is fitted over a narrow portion of the rod-form magnet (). The thickest portion of the magnet () and the spacer () contact the side wall of the tubular part () tightly, so that the magnet () is disposed coaxially with the tubular part (). A stopper () is formed on the opening () of the tubular part (), so that the magnet () does not move axially. Therefore, the magnet () is mounted in a prescribed position in a movable member () with a high degree of accuracy.

Magnetic field forming device and displacement sensor using same

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

Energy of returning pressurized fluid of an actuator is recovered and reused as energy for operating other accumulators. A first pump motor ( ) and a second pump motor ( ) are mechanically connected to form a pressure converter ( ), and a first circuit ( ), to which the returning pressurized fluid is supplied, is connected to the first pump motor ( ). A pressure accumulator ( ) is provided to a second circuit ( ) connected to the second pump motor ( ). The first circuit ( ) is connected to a discharge passage ( ) of a primary hydraulic pump ( ) by a third circuit ( ) and the pressure of a high pressure pressurized fluid is supplied to the discharge passage ( ) by the pressure of the high pressure pressurized fluid, and is reused.

Pressurized fluid recovery/reutilization system

A pressure compensating valve ( ) comprises a main valve ( ) that is operated in such a way as to increase the area of the opening between an inlet port ( ) and an outlet port ( ) by means of pressure acting on a first pressure receiving component ( ). The pressure compensating valve ( ) is also operated in such a way as to reduce the area of the opening by means of pressure acting on a second pressure receiving component ( ) and pressure acting on a third pressure receiving component ( ). The pressure compensating valve ( ) is designed to allow the pressure (Pa) of the pressurized oil flowing to the inlet port ( ) to act on the first pressure receiving component ( ) and the pressure (Pb) of the load driven by the pressurized oil flowing from the outlet port ( ) to act on the second pressure receiving component ( ). A control pressure producer ( B) is provided for allowing control pressure (Pe) resulting from a reduction in the pressure (Pa) of the inlet port ( ) to act on the third pressure receiving component ( ). An unloading pressure control valve and an variable bleed valve can also be provided. This structure allows the pressure compensated characteristics to be changed as desired. The unloading start pressure is also preset so as to improve response in terms of the hydraulic actuators. Energy loss can also be minimized, allowing the rapid start-up of the hydraulic actuators to be controlled, machines can be made smaller, and high precision control can be achieved.

Pressure compensating valve, unloading pressure control valve and hydraulically operated device

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

A discharged pressurized fluid of a primary hydraulic pump,driven by an engine,is supplied to an actuator,through an operating valve,. A first hydraulic rotary machine,for rotating a cooling fan,is driven to rotate by a returning pressurized fluid of the actuator,. A second hydraulic rotary machine,for rotating the cooling fan,is driven to rotate by the discharged pressurized fluid of an auxiliary hydraulic pump,which is driven by the engine,. By utilizing the returning pressurized fluid of the actuator,, the air blowing ability of the cooling fan is made high and the wasting of engine horse power is prevented.

Drive unit of cooling fan

An improved pressure fluid supply and delivery apparatus is disclosed that has a pressure compensating function and yet a reduced loss in pressure. The apparatus includes a variable displacement hydraulic pump unit(,) having a plurality of fluid discharge ports(,) independent each other and a common drive shaft. A plurality of fluid circuits (,) are connected to the plural discharge ports (,), respectively, and a plurality of fluid operated actuators (,) are connected via respective operating valves (,) to the plural fluid circuits (,), respectively. Also included in the apparatus is a displacement control means (,) operable in response to discharge pressures in the fluid discharge ports (,) and load pressures in the actuators (,) for controlling discharge fluid pressure of the variable displacement pump unit (,). A combining valve means (,) is disposed between the plural fluid circuits (,), for blocking fluid communication between them when the plural fluid discharge ports (,) have an equal pressure and operable to establish fluid communication between these fluid circuits via a constriction (,) in the presence of a difference in pressure between those fluid discharge ports.

Pressure fluid supply and delivery 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.

Growing community of inventors

Tochigi, Japan

Nobumi Yoshida