Abstract: A gear pump includes a pair of gears that meshes with each other, two rotational shafts inserted into the respective gears that rotate together with gears, a pair of side plates arranged adjacent to both side surfaces of the gears, each having two through-holes forming bearings of the two shafts, a seal block that abuts against the pair of side plates and covers a part of the pair of gears, a pump assembly having the gears, the two shafts, the pair of side plates, and the seal block, and a case having a recess to accommodate the pump assembly. A line passing through an arc center of a cylindrical surface inscribed in the facing surface of the case, and parallel to the two shafts, forms a rotating axis. When the pump assembly rotates about the rotating axis, one of the of side plates contacts the inner wall of the case.

Abstract: A gear pump (1) includes a pair of gears (4, 5) that meshes with each other, two shafts (2, 3) that are rotationally supported, inserted into the pair of respective gears, and rotate together with the pair of gears, a pair of side plates (7, 7?) that is arranged adjacent to both side surfaces of the pair of gears, and each have two through-holes forming bearings of the two shafts, a seal block (8) that abuts against the pair of side plates, and covers a part of the pair of gears in a circumferential direction, a pump assembly (10) having the pair of gears, the two shafts, the pair of side plates, and the seal block, and a case (12) having a recess (12a) in which the pump assembly is accommodated, and having a facing surface (12b) that faces the seal block on an inner wall forming the recess, in which the pump assembly (10) has a line passing through an arc center of a cylindrical surface which is inscribed in the facing surface (12b) of the case, and is parallel to two shafts (2, 3) as a rotating axis, and is

Abstract: In a roller screw (1) having a screw shaft (2), a plurality of rollers (4) that roll on a flank face (21a) of the screw shaft; and a cage (3) that rotatably houses the plurality of rollers, a plurality of roller groups (40) each having a plurality of rollers arranged at equal intervals while contacting with the same flank face along a spiral groove of the screw shaft for one lead are provided, and the plurality of roller groups are arranged at intervals in the axial direction of the screw shaft. With this configuration, the size of the nut portion in the axial direction of the screw shaft can be prevented from being bloated, and the load distribution in a circumferential direction of the screw shaft can be uniformized.

Abstract: In a roller screw (1) having a screw shaft (2), a plurality of rollers (4) that roll on a flank face (21a) of the screw shaft; and a cage (3) that rotatably houses the plurality of rollers, a plurality of roller groups (40) each having a plurality of rollers arranged at equal intervals while contacting with the same flank face along a spiral groove of the screw shaft for one lead are provided, and the plurality of roller groups are arranged at intervals in the axial direction of the screw shaft. With this configuration, the size of the nut portion in the axial direction of the screw shaft can be prevented from being bloated, and the load distribution in a circumferential direction of the screw shaft can be uniformized.

Abstract: A linear actuator (1) including a threaded shaft (51) and plural nuts (52) threaded onto the threaded shaft (51) to drive a drive target (55) with axial displacement of the threaded shaft caused by relatively rotating the threaded shaft (51) and the plural nuts (52) about an axis, includes: a link member (62) to connect two nuts of the plural nuts (52) and support the two nuts rotatably circumferentially of the threaded shaft (51); and a load transfer member (63) connected to the drive target to swingably support the link member (62). Thus, it is possible to easily reduce the difference between the loads applied to the nuts while reducing stiffness reduction of the load equalizing mechanism.

Abstract: A linear actuator includes an output rod having a flange portion on an outer peripheral surface thereof, an intermediate rod connected to a nut and having a flange portion on an outer peripheral surface thereof, a cage for housing therein coaxially the output rod and the intermediate rod and having a flange portion on an inner peripheral surface thereof at a position between the flange portion and the flange portion, a lid member disposed on a side of the output rod in the cage, a lid member disposed on a side of the intermediate rod in the cage, a coned disc spring housed between the flange portion and the flange portion, and a coned disc spring housed between the flange portion and the lid member.

Abstract: A highly reliable electrically-driven operating device that can automatically correct balance with a simple structure having a small number of parts used, and a working machine incorporating the same are provided. A first electrically-driven actuator 1 includes a first electric motor M1 having a rotor position sensor S. A second electrically-driven actuator 2 includes a second electric motor M2 not having a rotor position sensor. Outputs of the first electrically-driven actuator 1 and the second electrically-driven actuator 2 are combined by an unequal-length link 3.

Abstract: [Problem] To prevent an eccentric load from occurring in a nut member of a linear actuator and ensure a longer service life of the nut member. [Solution] The nut member is coupled to a driven member by a contact force equalizing mechanism having two rotation axes which are virtually perpendicular to each other, to absorb slight inclination between the nut member and the driven member and prevent occurrence of an edge load; also the point of intersection which is obtained when the two rotation axes are projected toward a threaded shaft is set as an optimum point of application of load for the nut member to let an external force transmitted from the driven member act on the optimum point of application of load to equalize the loads applied to the contact portions between the nut member and the threaded shaft and thereby prevent an eccentric load from occurring in the nut member.

Abstract: A linear actuator has an alternating drive apparatus, an alternating motion member, a fixing member fixed to a housing member, a direct acting member, a first wedge joining mechanism incorporated between the alternating motion member and the direct acting member, and a second wedge joining mechanism incorporated between the fixing member and the direct acting member. The first wedge joining mechanism and the second wedge joining mechanism have an inclined surface, a non-inclined surface at a constant distance from the central axis, and a wedge member arranged between the inclined surface and the non-inclined surface. The non-inclined surfaces of the first and second wedge joining mechanisms are formed on the direct acting member. The inclined surface of the first wedge joining mechanism is formed on the alternating motion member, and the inclined surface of the second wedge joining mechanism is formed to the fixing member.

Abstract: An external gear pump capable of achieving both a sealing property and a sliding property is disclosed. The external gear pump includes a pair of rotating shafts that are respectively pivotally supported by bearings provided in a casing; at least a pair of gears that are respectively fixed to the pair of rotating shafts and are externally meshed with each other; a side plate that is provided in sliding contact with one side surfaces of the pair of gears; and a seal block integrally including a side surface sliding part and a tooth tip sliding part. The external gear pump further includes movement restrictors on both sides of a straight line connecting axes of the pair of gears, and the movement restrictors restrict the seal block from moving with respect to the casing on a plane orthogonal to the rotating shafts.

Abstract: This invention includes a screw shaft 1, a screw thread 30 formed spirally on an outer periphery of the screw shaft, main rollers 4 with rolling surfaces 4c each of which comes into contact with a flank surface 1a of the thread, the main rollers each rolling along the flank surface by rotating about a rotational axis D, roller support members 6 each supporting one main roller so as to enable the main roller to rotate about the rotational axis, and a roller cage 2 supporting the roller support member so as to enable the support member to oscillate with respect to a force transmitted from the flank surface via the rolling surface to the main roller, the roller cage being constructed to turn about the screw shaft in relative form with respect to the screw shaft when the main roller rolls. Thus, the roller and the screw shaft reliably come into linear contact with each other, even if a backlash due to dimensional errors between parts exists between the parts.

Abstract: A linear actuator has an alternating drive apparatus, an alternating motion member, a fixing member fixed to a housing member, a direct acting member, a first wedge joining mechanism incorporated between the alternating motion member and the direct acting member, and a second wedge joining mechanism incorporated between the fixing member and the direct acting member. The first wedge joining mechanism and the second wedge joining mechanism have an inclined surface, a non-inclined surface at a constant distance from the central axis, and a wedge member arranged between the inclined surface and the non-inclined surface. The non-inclined surfaces of the first and second wedge joining mechanisms are formed on the direct acting member. The inclined surface of the first wedge joining mechanism is formed on the alternating motion member, and the inclined surface of the second wedge joining mechanism is formed to the fixing member.

Abstract: This invention includes a screw shaft 1, a screw thread 10 formed spirally on an outer periphery of the screw shaft, a plurality of rollers 2 arranged along the thread so as to be spaced from one another in a circumferential direction of the screw shaft to roll along a flank surface la of the screw thread via a rolling surface 2c, and a roller cage 3 accommodating the plurality of rollers so as to rotate each of the rollers on respective axes and constructed so that when the rollers are made to roll, the cage moves about the screw shaft in relative form with respect thereto; wherein the rollers each have a central axis 26 fixedly positioned with respect to the roller cage so that the roller takes a posture making a line imaginarily extended from the central axis intersect the screw shaft, and so that the central axis is inclined towards the flank surface with which the rolling surface comes into contact.

Abstract: In a method for utilizing a wedge engagement mechanism as means for retaining an output shaft without requiring a large driving power, there is a need for preventing fatigue life of an actuator from being reduced as a result of stress at contacting portions of parts of wedge engagement portions of the wedge engagement mechanism becoming large. In a linear actuator that converts rotary motion of a drive unit for rotation to linear motion through a rotary motion-to-linear motion conversion mechanism, a one-way mechanism is disposed upstream of the rotary motion-to-linear motion conversion mechanism in a rotational drive path, to thereby inhibit, with a small wedge engagement force, the output shaft from being driven by an external force, achieving reduction in the stress at the contacting portions.

Abstract: A lead screw apparatus includes a screw shaft having a spiral channel on an outer circumferential surface thereof, a plurality of rollers rotatable with contact with the spiral channel, and a cage rotatably supporting the rollers for conversion between relative rotation and linear motions between the screw shaft and the cage bi-directionally. The lead screw apparatus further includes a bearing and a holder 6 supported by the case for supporting the bearing. An inner ring of the bearing and the roller are integrally formed. An outer ring of the bearing has a protrusion on an outer circumferential surface thereof on a side closer to the screw shaft. Rollers of the bearing having a circular truncated cone shape are disposed in the bearing in a circumferential direction with substantially no gap. The outer ring has a thread part to shift the bearing and the roller.

Abstract: Provided is a liquid chromatograph pump system which sucks eluent from an eluent reserving container, and which feeds pressurized high pressure eluent into a column, wherein a plunger reciprocating in a cylinder is formed on its outer peripheral surface with a stepped part along the sliding direction of the plunger in the cylinder so as to define a working chamber between the stepper part and the inner wall surface of the cylinder, the flow rate of the liquid chromatograph pump being determined by the volume of the working chamber and the traveling speed of the plunger, thereby it is possible to stably feed a liquid at an extremely low flow rate, and to satisfactorily expel air bubbles upon a start of the liquid chromatograph pump system.

Abstract: A plurality of advanced angle chamber oil paths communicated to advanced angle hydraulic chambers and a plurality of retarded angle chamber oil paths communicated to retarded angle hydraulic chambers according to a change in rotating angle of a cam shaft are provided. The plurality of advanced angle chamber oil paths and the plurality of retarded angle chamber oil paths, respectively, are switched between communication and cut-off according to a rotating angle of the cam shaft. When torque in the direction of advanced angle acts in an advanced angle mode for phase shifting in the direction of advanced angle, the advanced angle hydraulic chambers are caused to communicate to a hydraulic power source and the retarded angle hydraulic chambers are caused to communicate to a drain.

Abstract: A device for controlling a phase of a cam shaft in an internal combustion engine has a structure which can return a phase of a cam shaft to an intermediate position on the basis of its own power by utilizing a variable torque applied to a cam shaft at a time of starting an engine so as to lock, and has a high practicability and mass production performance.

Abstract: A parallel guide portion as an integral structure of a sprocket and a vane, as well as a slant guide portion, are arranged alternately on the same circumference, with circumferential gaps being formed between said guide portion and the parallel guide portion, said guide portion having a shape such that the circumferential gaps become smaller in one axial direction of a cam shaft. Wedge members are disposed in the circumferential gaps respectively and are moved in one axial direction to fill up the circumferential gaps, thereby fixing the phase between the sprocket and the vane into a locked state. The wedge angle of each wedge member is set sufficiently small and, by utilizing varying torques acting on the cam shaft, said members are each moved and locked in one axial direction with a spring. Said members are actuated in an opposite axial direction with oil pressure to release the locked state, thereby permitting a phase angle control.

Abstract: A linear actuator has an alternating drive apparatus, an alternating motion member, a fixing member fixed to a housing member, a direct acting member, a first wedge joining mechanism incorporated between the alternating motion member and the direct acting member, and a second wedge joining mechanism incorporated between the fixing member and the direct acting member. The first wedge joining mechanism and the second wedge joining mechanism have an inclined surface, a non-inclined surface at a constant distance from the central axis, and a wedge member arranged between the inclined surface and the non-inclined surface. The non-inclined surfaces of the first and second wedge joining mechanisms are formed on the direct acting member. The inclined surface of the first wedge joining mechanism is formed on the alternating motion member, and the inclined surface of the second wedge joining mechanism is formed to the fixing member.