Abstract: A pressure compensated electromagnetic proportional directional flow control valve of the present invention integrally includes: an electromagnetic proportional directional flow control valve configured to be driven by a solenoid; and a pressure compensated valve configured to carry out pressure compensation of a flow rate controlled by the electromagnetic proportional directional flow control valve. A pressure compensation spool moves so as to balance forces of a spring, a first pressure chamber, and a second pressure chamber. With this, the pressure compensation for maintaining a constant pressure difference between an upstream side and a downstream side of a first variable aperture can be carried out, and a surplus liquid of a liquid flowing from a liquid-pressure supply port to a derivation port can flow out from a branch port to outside.

Abstract: A valve device includes a temperature sensor disposed to project from a housing to a tank inner space to detect the temperature in the tank inner space, and can detect the temperature without being influenced by the heat capacity of the housing. A coil generates a magnetic force to drive a valve with three terminals arranged at different positions in an axial direction, and a drive voltage is selectively applied between two of the terminals. A current value of the driving current which energizes the coil can be changed by selecting the terminals between which the drive voltage is applied. Without controlling the drive voltage, it is possible to suppress wasting power such that the driving current of the large current value is generated in the start-up time, and the current value of the driving current is decreased in the holding time.

Abstract: A swash plate type piston pump motor is configured such that: a plurality of pistons are arranged in a circumferential direction in a cylinder block configured to rotate with a rotating shaft; the pistons reciprocate such that tip end portions thereof are guided by a smooth surface of a swash plate; and the swash plate is slidably supported by a concave surface of a swash plate support of a convex surface to be able to tilt with respect to a rotating axis, and concave surfaces and of the swash plate support include quenched portions which are partially quenched by laser light.

Abstract: The present invention provides a small-size light-weight electric motor integrated hydraulic motor which is simple in configuration, integrally includes an electric motor and a hydraulic motor, and is capable of efficiently operate, by being configured such that: a swash plate type hydraulic motor and an electric motor driven by the swash plate type hydraulic motor are provided in one casing; the casing is filled with oil; a driving shaft of the swash plate type hydraulic is configured to extend from a front end portion of the casing up to a rear end portion thereof and be supported at the front and rear end portions of the casing; the swash plate type hydraulic motor and a rotor of the electric motor are provided in series at the driving shaft; and a stator of the electric motor is fixed to an inner side portion of the casing.

Abstract: A pressure compensated electromagnetic proportional directional flow control valve of the present invention integrally includes: an electromagnetic proportional directional flow control valve configured to be driven by a solenoid; and a pressure compensated valve configured to carry out pressure compensation of a flow rate controlled by the electromagnetic proportional directional flow control valve. A pressure compensation spool moves so as to balance forces of a spring, a first pressure chamber, and a second pressure chamber. With this, the pressure compensation for maintaining a constant pressure difference between an upstream side and a downstream side of a first variable aperture can be carried out, and a surplus liquid of a liquid flowing from a liquid-pressure supply port to a derivation port can flow out from a branch port to outside.

Abstract: Under emergency, a valve body displaced from a closed position to an open position in association with melting of a fuse member receives resultant of pressing forces of a primary pressure of gas guided through a primary port in an opening direction in a state where the valve body is disposed at the position closer to the open position including a fluid driving start position between the closed position and the open position. The valve body receives smaller resultant of the pressing forces of the primary pressure in the opening direction in a state where the valve body is disposed at the position closer to the closed position than to the fluid driving start position than the resultant of the pressing forces received by the valve body in the state where the valve body is disposed at the position closer to the open position including the fluid driving start position.

Abstract: A screw loosening prevention structure and a gas-pressure device are provided. The structure includes a first member that is formed with a container space filled with gas, and includes a first threaded portion, a second member that includes a second threaded portion, wherein the second member is threadedly coupled with the first member by threadedly engaging the second threaded portion with the first threaded portion, and receives a pressure from the gas in the container space of the first member, and a spring member provided between the first and second members in a deformed state in which the displacement of the spring member is greater than a relative displacement of the first and second members due to a loosening factor including the gas pressure that is received by this second member.

Abstract: To provide an attachment structure of a swash plate support, that is, an attachment structure which suppresses an unstably fixed state of the swash plate support and realizes easy attachment and detachment of the swash plate support to and from a casing. A casing of a piston pump and a swash plate support which is attachable to the casing include a displacement preventing device and a rotation preventing device. In the swash plate support and the casing, since an engaging pawl portion of the displacement preventing device engages with an engaging portion, relative displacements in a first direction and a second direction along the rotational axis are prevented, and since a pin member of the rotation preventing device fits in the pin fit hole, relative rotations around the rotational axis are prevented.

Abstract: A pressure-reducing valve includes a housing, a pressure-reducing piston, a driving piston, and a spring mechanism. The housing is provided with a primary port and a secondary port. The pressure-reducing piston is displaceably retained in an interior of the housing. The pressure-reducing piston is displaced to control an opening degree of the primary port and configured to separate the interior of the housing into a primary-pressure space connected to the primary port and a secondary-pressure space connected to the secondary port. The driving piston is displaceably retained in the interior of the housing. The driving piston is displaced to cause the pressure-reducing piston to be displaced in association therewith and has a secondary-pressure receiving surface that receives a secondary pressure from a fluid in the secondary-pressure space. The spring mechanism is configured to exert a spring force against the secondary pressure to at least one of the pistons.

Abstract: The present invention provides a method for manufacturing a swash plate type piston pump motor in which: a plurality of pistons are arranged in a circumferential direction on a cylinder block configured to rotate with a rotating shaft; the pistons are guided along a swash plate to reciprocate by rotation of the rotating shaft; a convex portion of the swash plate is slidably supported by a recess of a swash plate support; and a wall formed integrally with the swash plate support is arranged on a normal to at least a part of a supporting surface of the recess, wherein: the supporting surface of the recess is quenched by irradiating the supporting surface with laser light while causing the laser light to scan the supporting surface; and outputs of the laser light are changed in accordance with incidence angles of the laser light with respect to the supporting surface.

Abstract: [Object] Increase abrasion resistance and seizing resistance of a slide surface of each of a swash plate and a swash plate support while improving productivity. [Means to Achieve Object] A swash plate type piston pump motor 1 is configured such that: a plurality of pistons 10 are arranged in a circumferential direction in a cylinder block 9 configured to rotate with a rotating shaft 5; the pistons 10 reciprocate such that tip end portions 10a thereof are guided by a smooth surface 26a of a swash plate 12; and the swash plate 12 is slidably supported by a concave surface 22 of a swash plate support 4 of a convex surface 32 to be able to tilt with respect to a rotating axis L, and concave surfaces 21 and 22 of the swash plate support 4 include quenched portions 21a and 22a, respectively, which are partially quenched by laser light.

Abstract: A pump apparatus which is expected to realize satisfactory work efficiency of an assembly operation, reduction of noise and suppression of rust comprises: two pump units (22 and 23); a valve unit (24) provided between the pump units (22 and 23); and a fastening means (36) for fastening the pump units (22 and 23) to each other such that the valve unit (24) is able to be held by the pump units (22 and 23) therebetween.

Abstract: To provide an attachment structure of a swash plate support, that is, an attachment structure which suppresses an unstably fixed state of the swash plate support and realizes easy attachment and detachment of the swash plate support to and from a casing. A casing of a piston pump and a swash plate support which is attachable to the casing include a displacement preventing device and a rotation preventing device. In the swash plate support and the casing, since an engaging pawl portion of the displacement preventing device engages with an engaging portion, relative displacements in a first direction and a second direction along the rotational axis are prevented, and since a pin member of the rotation preventing device fits in the pin fit hole, relative rotations around the rotational axis are prevented.

Abstract: An electrical signal input type displacement control device capable of reducing pipes on hydraulic equipment, and hydraulic equipment including the same. The pump equipment includes two the pump units. Electrical regulators are disposed for the pump units. In each of the electrical regulators, a solenoid proportional valve changes a supply status of driving oil. A pilot piston activates a servo switching valve in accordance with a supply status of the supplied driving oil, and controls a supply status of mechanism driving oil supplied to a servo mechanism. Servo mechanisms change the capacities of the pump units in accordance with the supply status. In the electrical regulators, a driving oil passage connects the input port to an inter-pump passage.

Abstract: A holding control valve of the present invention is configured such that: a spool is configured to perform strokes by a piston configured to operate by introduction of pilot pressure and have a larger diameter than the spool; the piston is divided into a pilot piston configured to receive the pilot pressure and a relief operation piston disposed adjacent to the spool to receive pressure of relief oil discharged when a relief valve operates; and the relief oil is introduced to between the pilot piston and the relief operation piston.

Abstract: A valve device includes a temperature sensor disposed to project from a housing to a tank inner space to detect the temperature in the tank inner space, and can detect the temperature without being influenced by the heat capacity of the housing. A coil generates a magnetic force to drive a valve with three terminals arranged at different positions in an axial direction, and a drive voltage is selectively applied between two of the terminals. A current value of the driving current which energizes the coil can be changed by selecting the terminals between which the drive voltage is applied. Without controlling the drive voltage, it is possible to suppress wasting power such that the driving current of the large current value is generated in the start-up time, and the current value of the driving current is decreased in the holding time.

Abstract: A plunger (45) and a piston (46) are displaceably held in a housing (104) for opening and closing a valve path (107) defined in the housing (104), and a single common seat block (44) provided for the plunger (45) and the piston (46) is fixed to the housing (104) and has seat portions (47) each formed from a soft material for respective of the plunger (45) and the piston (46) to be pressed thereon. This arrangement provides a valve device which is simplified in structure and can be manufactured with reduced man-hour.

Abstract: A guide body for an electromagnetic valve device is provided. The device includes a coil assembly surrounding the guide body, a plunger driven by magnetic force and slidably disposed inside the guide body. The guide body slidably guides the plunger in an open/close direction of the valve body along a guide face thereof. The guide body includes a first nonmagnetic section that supports a pole body and a part of the plunger at which the pole body and the plunger oppose each other, a second nonmagnetic section that supports the valve body, and extends at least throughout a sliding range of the valve body, and a magnetic section intermediate the first and second sections so that a portion of the lines of magnetic force passes therethrough. The guide face is formed so as to coaxially support the plunger and the valve body displaceable in the open/close direction.