Komatsu Corporation

Kabushiki Kaisha Komatsu Seisakusho

Lapis Technology Co., Ltd.

Mitsuru Arai

Sadao Nunotani

Seita Hayashi

Shigeru Shinohara

Hideki Kado

Hideyori Sato

Mitsuru Oshiro

Takayuki Muto

Hiroshi Endo

Naoki Ishizaki

Nobuaki Inaba

Toshiyuki Yoshida

Yoshikazu Nagahara

Takeo Iida

Koichi Morita

Seiichi Hasegawa

Michio Onzou

Shoichiro Inatomi

An output driver according to the disclosure includes a differential signaling circuit that includes a first transistor that generates a bias current, first and second nodes, and a resistor circuit connected between the first and second nodes, and outputs voltages respectively at the first and second nodes as a pair of differential signals by supplying the bias current to one of the first and second nodes based on a level of the input signals, a differential voltage circuit that supplies a differential voltage representing a difference between a center voltage of voltages between the first node and the second node and a predetermined reference voltage to a gate of the first transistor; and a pre-emphasis circuit that executes a pre-emphasis processing in response to changes in the level of the input signal, generating a current based on the differential voltage and adding it to the bias current.

Output driver and display device

An axial hydraulic pump-motor, in which a cylinder block having a plurality of cylinder bores on a valve plate having a high-pressure side port and a low-pressure side port for controlling an amount of reciprocation of a piston in each of the cylinder bores, the hydraulic pump-motor includes: a residual pressure release port provided on the valve plate and communicating until the cylinder bore on a top dead center side communicates with the low-pressure side port; a residual pressure acquisition portion obtaining a value of a residual pressure in the cylinder bore on the top dead center side; and a directional switching valve switching a flow path between the residual pressure release port and an hydraulic oil tank and a flow path between the residual pressure release port and the low-pressure side port.

Hydraulic pump-motor

In a hydraulic piston pump, a cylinder port can communicate with a discharge port after a system pressure and a chamber pressure in a cylinder bore becomes in an equilibrium condition. A through hole opening to a surface on which a cylinder block slides in a valve plate is allowed to communicate with a side of one end surface of a balance valve, and the system pressure of a discharge port side is supplied to the other end surface of the balance valve. In the balance valve, a balance piston which slides by a pressure difference between the chamber pressure of the cylinder bore and the system pressure is accommodated. Before the cylinder port communicates with an oil guiding groove, the chamber pressure can be equilibrated to the system pressure by an activation of the balance piston.

Hydraulic piston pump with a balance valve

Hydraulically actuated breaker with lost-motion prevention device

Counter balance valve

Hydraulic ramming apparatus

A communication area of a left pressure reception chamber, a pressure reception chamber, a right pressure reception chamber and another pressure reception chamber for moving a spool to first and second positions with a first pump port and a second pump port is made large at the beginning of a stroke, small at the intermediate of the stroke and medium at the end of the stroke so as to return the spool from the first and second positions to the neutral position in a short time while preventing cavitation from occurring. While the volume of the pressure reception chamber located opposite to the moving direction of the spool is prevented from changing, the spool is moved slowly in the above-described opposite direction. Thus, the spool is prevented from making an over-stroke and also prevented from having a hunching even if a return pressure oil has a large change in pressure.

An emergency stop apparatus for a hydraulic speed change gear is capable of quickly reducing the pump discharge to zero in order to stop the traveling of a vehicle at the time of an emergency, where the vehicle employs a hydraulic travel drive system, such as in construction equipment, agricultural equipment, etc. The apparatus includes a variable capacity type hydraulic pump (41); a hydraulic motor (43); a travel operating level (59); an intermediate lever, which is connected to the travel operating lever by a wire cable; a servo valve (52); a servo valve input lever (57), which is attached to the servo valve; and an interlock device between the intermediate lever and the servo valve input lever. When the interlock device is engaged, the servo valve input lever is actuated according to the operation of the travel operating lever so as to displace the servo valve in accordance with the operating amount of the travel operating lever to increase or decrease the discharge of the variable capacity type hydraulic pump so as to change the rotational speed of the hydraulic motor. When the interlock device is disengaged, the servo valve input lever is not connected to the intermediate lever. An emergency stop switch can actuate a solenoid valve to pass pressurized oil to a detent means to effect disengagement of the servo valve input lever from the intermediate lever.

Emergency stop apparatus for hydraulic speed change gear

Hydraulic braking apparatus having two safety valves

Swash plate angle changing apparatus for a piston pump/motor of swash

Swash plate type piston pump/motor

A variable displacement hydraulic motor is easily mounted on a power shovel without interfering with a truck frame of the power shovel and without projecting outward therefrom. The hydraulic motor is easily assembled and machined in its manufacturing. In the hydraulic motor (M'), there is provided an end cover (57) in which is slidably mounted a piston lever (69) which is oppositely disposed from a drive shaft (44) of the hydraulic motor (M') to extend in a direction perpendicular to an axis of the drive shaft (44). Since the hydraulic motor (M') is provided with a valve plate swinging unit having a pin (71) through which the piston lever is connected with a valve plate (59) fixedly mounted on a cylinder block (60), it is possible to directly mount the end cover (57) on a main casing (50) of the hydraulic motor (M') so as to be perpendicular to the axis of the drive shaft (44).

Variable displacement hydraulic motor

A control apparatus for a hydraulic motor for use in a construction vehicle driven by hydraulic power has a hydraulic motor, a hydraulic pump serving as a pressurized fluid supply source, a manually operable directional control valve connected across supply and discharge conduits for the hydraulic motor, a brake valve section including a counterbalancing valve and a pair of relief valves all of which are connected across the conduits extending between the directional control valve and the hydraulic motor, and a selector valve for controlling the supply of control pressurized fluid introduced through a shuttle valve connected across the conduits into a displacement control cylinder contained in the hydraulic motor. The selector valve is of a pilot operated type remotely controlled by pilot pressurized fluid supplied from an external pressurized fluid supply source.

Control apparatus for hydraulic motor

A hydraulic circuit is disclosed for driving a bidirectional hydraulic motor from a pump via a hand operated directional control valve, as for propelling an earthmover or actuating an implement assembly thereon. For mitigating an abrupt pressure rise as when the motor is set into or out of rotation, the circuit has a pair of oppositely directed dual pressure relief valves connected in parallel with each other between a pair of main lines extending between motor and directional control valve. Each dual pressure relief valve is normally conditioned to pass at a predetermined lower pressure the pressurized fluid from one of the main lines and to pass at a predetermined higher pressure the pressurized fluid from the other main line. When pilot operated from a timing valve responsive to a pressure differential between the main lines, that one of the relief valves which has been bleeding off the pressurized fluid at the low pressure is closed, with the result that the pressurized fluid is then released at the high pressure through the other relief valve, thereby causing two stepwise pressure rises for the reduction of a shock. The invention proposes the provision of a variable resistor between the timing valve and each main line for variably delaying the pilot actuation of the relief valves by the timing valve.

Fluid circuit for operating a bidirectional hydraulic motor with a

A hydraulic brake valve system for use in a hydraulic circuit consisting of driving and braking fluid lines and including therein at least a hydraulic motor for the actuation of an inertia body such as, for example, a construction vehicle or work implements thereof has a counterbalance valve, a cross-over safety valve, a drain change-over valve and a timer valve. The cross-over safety valve consists of two common relief valves, each having two pressure receiving surfaces and adapted to relieve pressurized fluid acted on one of the pressure receiving surfaces at a low pressure and relieve pressurized fluid acted on the other pressure receiving surface at a high pressure, wherein the first port of one of said relief valves is connected with said driving fluid line and the second port thereof is connected with said braking fluid line, whilst the first port of the other relief valve is connected with said braking fluid line and the second port thereof is connected with said driving fluid line.

Growing community of inventors

Yokohama, Japan

Mitsuru Arai