Abstract: To provide a hydraulic driving device configured to smoothly extend a hydraulic cylinder. The present invention includes the open circuit E, the closed circuit A, a control device 57, and a control lever 56a. The open circuit E is provided with a flow passage 202 for connecting an outlet port of the open circuit pump 13 and a head chamber 1a of the boom cylinder 1, a selector valve 44a provided in the flow passage 202, a discharge flow passage 404 for connecting a hydraulic fluid tank 25 and a flow passage 200, and a bleed-off valve 64 provided in the discharge flow passage 404. The control device 57 is configured in such a manner that when a manipulate signal for extending the boom cylinder 1 is input from the control lever 56a, the bleed-off valve 64 is closed, the selector valve 44a is subsequently opened, and the open circuit pump 13 is controlled.

Abstract: Delivery ports of a closed circuit hydraulic pump 2a/2b are connected to a head-side chamber and a rod-side chamber of an arm/boom cylinder 7a/7b. A switching valve 12a/12b is arranged between the head-side chamber of the cylinder and a delivery port of an open circuit hydraulic pump 1a/1b. A proportional control valve 14a/14b is arranged between the head-side chamber of the cylinder and a hydraulic fluid tank. At times of cylinder extension, both of the closed circuit hydraulic pump and the open circuit hydraulic pump and the switching valve are controlled so that the delivery flows from the closed circuit hydraulic pump and the open circuit hydraulic pump are sent to the head-side chamber. At times of cylinder retraction, the closed circuit hydraulic pump and the proportional control valve are controlled so that part of an outward flow from the head-side chamber is returned to the closed circuit hydraulic pump and other part of the outward flow is returned to the hydraulic fluid tank.

Abstract: There is provided a driving device for a work machine, having a closed hydraulic circuit system for driving cylinders with hydraulic pumps, the driving device making the speed of operation substantially the same in both directions of piston rod extension and contraction.

Abstract: A hydraulic closed circuit system using a single rod type hydraulic cylinder prevents hunting of a flushing valve due to a delay in response of the flushing valve and circuit pressure pulsations, thereby preventing a decreasein operability of the hydraulic cylinder. A single rod type hydraulic cylinder is connected to a hydraulic pump via two hydraulic lines. A flushing valve is connected between the hydraulic lines and a tank; and a control unit is configured to add a predetermined control parameter to a pressure in a lower-pressure hydraulic line of the two hydraulic lines. The magnitude of a pressure in the higher-pressure hydraulic line of the two hydraulic lines is compared with the magnitude of a compensation pressure to which the control parameter has been added, and the flushing valve is switched when the compensation pressure and the higher-pressure hydraulic line pressure are found to be reversed in magnitude.

Abstract: A sound generator is provided capable of generating vehicle sound that will be produced when a specific sound element is changed out of a plurality of sound elements arising from the operation of a plurality of components mounted on a vehicle.

Abstract: A drive system suppresses cylinder speed fluctuation at times of load inversion in a hydraulic closed circuit system in which a single rod cylinder is driven by a hydraulic pump. The drive system has a control device including: pressure detection means which detect pressure in a rod-side hydraulic chamber of the hydraulic cylinder and pressure in a head-side hydraulic chamber of the hydraulic cylinder; load calculation means which calculates the load on the hydraulic cylinder from the pressure in the rod-side hydraulic chamber and the pressure in the head-side hydraulic chamber; load switching means which calculates a first proportional gain in accordance with the polarity of the calculated load; and multiplication means which calculates a command signal by multiplying the calculated first proportional gain and an operation amount input from the operating device together and outputs the calculated command signal to the delivery flow rate control means.

Abstract: The present invention provides a system for driving a working machine, while the system achieves high energy saving, the system improving installability by downsizing hydraulic pumps and motors, and having extensibility enabling an attachment to be easily added. A system for driving a working machine according to the invention includes: a plurality of hydraulic closed circuits that connect hydraulic pumps to hydraulic actuators in a closed circuit manner; hydraulic open circuit that connects a hydraulic pump to hydraulic actuators in an open circuit manner; first assist circuits that connect between the hydraulic closed circuits so as to cause a hydraulic fluid to be mutually supplied between the hydraulic closed circuits; and second assist circuits that connect the hydraulic closed circuits to the hydraulic open circuit so as to cause the hydraulic fluid to be supplied from the hydraulic closed circuits to the hydraulic open circuit.

Abstract: There is provided a mechanism for converting rotary motion into linear motion in which high positioning accuracy can be obtained in mutual conversion between rotary motion and linear motion. The mechanism includes a plurality of rollers having a roller annular groove member and a pair of thrust bearings, a thrust bearing portion that is convex shaped and is held between the pair of thrust bearings on an outer surface of an end of the roller shaft, a step surface that is disposed on an inner surface of the roller annular groove member and facing to the thrust bearing portion putting one of the pair of thrust bearing in between, a thrust facing member that is in mesh with an inner surface of the roller annular groove member and is facing to the thrust bearing portion putting the other one of the pair of thrust bearing in between.

Abstract: A rotational-to-linear conversion mechanism inhibits interference from occurring in places except for an engagement site to increase the efficiency of conversion mechanism and reliability, which has: a rack rod 1 including thread on its outer peripheral face; a holder member 3 provided on the outer periphery of the rack rod, rotating about the rack rod and moving in the axis direction; and revolving rollers 21 rotatably supported in the holder member, each having ring-shaped grooves formed in its outer peripheral face to be engaged with the thread, and placed at an axis angle with respect to a center axis of the rack rod to allow the ring-shaped grooves to be engaged with the thread on the rack rod. A contact face of the thread with each ring-shaped groove in an engagement site of the thread and the ring-shaped groove is formed as a convex face having different curvatures in a radial direction.

Abstract: A mechanism for converting rotary motion into linear motion includes a rod having a thread or threaded part at its outer peripheral surface, and a holder member on the outer peripheral surface of the rod, rotatable relative to the rod, and axially movable relative to the rod. Rollers are supported rotatably by the holder member and have annular grooves at their outer peripheral surfaces. Each roller is torsionally disposed at an axial angle greater than or equal to a lead angle of the thread with respect to a central axis of the rod. Both ends of the roller shaft are secured to the holder member, and the mechanism has a structure in which a hole having a diameter greater than that of the roller shaft is provided at one end of the holder member and the roller shaft is secured by a roller mounting member.

Abstract: It is possible to correctly determine whether a change in the pressure or flow rate is caused by normal opening and closing operations of a check valve and to monitor in real time whether an operation of a check valve is normal or abnormal in a liquid supply device. Light is introduced in the check valve and a change in the quantity of light transmitted through or reflected by the check valve, caused by the opening and closing of the valve is detected, so that the opening and closing operations of the check valve can be directly detected. The check valve is arranged in a pipe in the liquid supply device, and a change in the pressure in the pipe is monitored on the basis of a signal from a pressure sensor and a signal which represents the opening and closing of the check valve.

Abstract: In a drive unit of a fuel injection device, an electric current is supplied to the fuel injection device by applying a high voltage to the fuel injection device from a high voltage source whose voltage is boosted to a voltage higher than a battery voltage at the time of opening a valve of the fuel injection device. Thereafter, the electric current supplied to the fuel injection device is lowered to a current value at which a valve element cannot be held in a valve open state by stopping the applying of the high voltage from the high voltage source. Thereafter, in a stage where a supply current is switched to a hold current, another high voltage is applied to the fuel injection device from the high voltage source.

Abstract: A pump controller causes a first plunger pump and a second plunger pump connected in series or in parallel to perform intake and compression actions alternately at substantially constant cycles, sets a pressurizing chamber of one of the plunger pumps to a state of a higher pressure than the pressurizing chamber of the other plunger pump, and performs flow rate control by adjusting lift amounts of the first plunger and the second plunger. Thus, it is possible to provide a pump for liquid chromatograph, and a liquid chromatograph, which are capable of reducing pulsations even when an ejection flow rate is changed.

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: It is possible to correctly determine whether a change in the pressure or flow rate is caused by normal opening and closing operations of a check valve and to monitor in real time whether an operation of a check valve is normal or abnormal in a liquid supply device. Light is introduced in the check valve and a change in the quantity of light transmitted through or reflected by the check valve, caused by the opening and closing of the valve is detected, so that the opening and closing operations of the check valve can be directly detected. The check valve is arranged in a pipe in the liquid supply device, and a change in the pressure in the pipe is monitored on the basis of a signal from a pressure sensor and a signal which represents the opening and closing of the check valve.

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: 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: A rotational-to-linear conversion mechanism inhibits interference from occurring in places except for an engagement site to increase the efficiency of conversion mechanism and reliability, which has: a rack rod 1 including thread on its outer peripheral face; a holder member 3 provided on the outer periphery of the rack rod, rotating about the rack rod and moving in the axis direction; and revolving rollers 21 rotatably supported in the holder member, each having ring-shaped grooves formed in its outer peripheral face to be engaged with the thread, and placed at an axis angle with respect to a center axis of the rack rod to allow the ring-shaped grooves to be engaged with the thread on the rack rod. A contact face of the thread with each ring-shaped groove in an engagement site of the thread and the ring-shaped groove is formed as a convex face having different curvatures in a radial direction.

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 sound generator is provided capable of generating vehicle sound that will be produced when a specific sound element is changed out of a plurality of sound elements arising from the operation of a plurality of components mounted on a vehicle.