Abstract: A relief valve relieves hydraulic fluid from a first port to a second port, and includes a housing and an adjustment member capable of advancing and retracting; a seat member with a relief passage connecting to the two ports; a relief valve body that is unseated from or seated on the seat member to open or close the relief passage, and that receives pressure of the first port in a direction of opening the relief passage; a first biasing member that biases the relief valve body against the pressure of the first port, with a force adjusted by the adjustment member; a check valve body that opens or closes a check passage connecting to the two ports, and that receives pressure of the second port in a direction of opening the check passage; and a second biasing member that biases the check valve body.

Abstract: A hydraulic operated valve includes an electromagnetic adsorption mechanism and a steel ball. In the electromagnetic adsorption mechanism, when a current is supplied, an adsorption plate is adsorbed by a solenoid. By this adsorption, a steel ball is pressed against an outer surface of a cam disc. The outer surface of the cam disc includes two steps. When the cam disc is rotated clockwise or counterclockwise, the pressed steel ball engages the two steps. Thus, the cam disc is detented. These two steps are configured such that when the cam disc is returned to a neutral position, the adsorption plate is separated from the solenoid against the pressing of the electromagnetic adsorption mechanism. Thus, the detent state of the cam disc is canceled.

Abstract: A hydraulic operated valve includes an electromagnetic adsorption mechanism and a steel ball. In the electromagnetic adsorption mechanism, when a current is supplied, an adsorption plate is adsorbed by a solenoid. By this adsorption, a steel ball is pressed against an outer surface of a cam disc. The outer surface of the cam disc includes two steps. When the cam disc is rotated clockwise or counterclockwise, the pressed steel ball engages the two steps. Thus, the cam disc is detented. These two steps are configured such that when the cam disc is returned to a neutral position, the adsorption plate is separated from the solenoid against the pressing of the electromagnetic adsorption mechanism. Thus, the detent state of the cam disc is canceled.

Abstract: A machine tool includes a spindle to which a tool is detachably attached to be clamped, an unclamping lever provided for rocking motion and having two ends, rocking means for rocking the unclamping lever, a releasing section provided in the spindle so as to be pressed by the unclamping lever when the unclamping lever is rocked by the rocking means with a tool being clamped by the spindle, thereby releasing the tool from a clamped state, and a support shaft for rockably supporting the unclamping lever, the support shaft being movable axially with respect to the spindle.

Abstract: When pairs of fingers grasp tools and a tool exchange arm starts lowering, upper ends of lock pins which have been held by a spindle head are released, the lock pins are pushed up by urging forces of springs, and tapered portions of the lock pins push out steel balls to external sides. Thus, cylindrical portions of the pairs of fingers are prevented from opening, and opening and closing of the pair of fingers are locked.

Abstract: A bearing unit includes two pairs of bearings, a housing for housing the bearings and a flange through which the shaft is inserted. In order to prevent the invasion of cutting chips or cutting oil into the bearings, the flange is provided with a circumferential groove on the inner surface of the flange, and an air supply port which opens in the circumferential groove for introducing compressed air to the groove. The axial direction of the supply port is parallel to a tangent of the shaft, so that the compressed air is effectively introduced in the circumferential direction of the shaft. Therefore, the air blow created by the compressed air in the clearance becomes uniform along the circumference of the shaft, which enables to effectively prevent the invasion of cutting chips and cutting oil.

Abstract: A tool magazine having a plurality of grips for gripping tool holders for use in a machine tool. The tool holder gripped at the grip is transferred to a holder portion of a spindle of a machine tool, or the tool holder held in the holder portion is transferred to the grip. The magazine has a magazine disk rotatable about a horizontal axis for tool indexing operation. The tool holder extends in the horizontal direction when it is gripped by the grip, and the spindle also extends in the horizontal direction. Each grip includes a pair of first and second arm members pivotally supported on the magazine disk and extending in a radial direction of the magazine disk. The first and second arm members has tool gripping portions movable toward and away from each other for gripping and releasing the tool holder. A compression spring is provided between the pair of first and second arm members for normally urging the first and second arm members to their tool gripping positions.

Abstract: A control device for a tool driving unit is disclosed wherein a tool such as a tap or a drill is controlled to be rotated and axially moved by the control device. The tool driving unit has a spindle servo motor adapted to be driven according to a spindle current command and a feed shaft servo motor adapted to be driven according to a feed shaft current command which are provided by a single microcomputer which operates as the control device. The microcomputer reads an NC program and outputs a spindle command for the spindle servo motor when performing tapping, and outputs both the spindle command and a first feed shaft command for the feed shaft servo motor when performing drilling. A thread pitch changing controller for controlling a thread pitch outputs a second feed shaft command for the feed shaft servo motor when performing tapping.

Abstract: A tool driving unit for moving a tool in axial direction thereof and for rotating the tool about its axis. The tool driving unit comprises a spindle supported in the housing frame, a tool chuck mounted on the one end portion of the spindle for holding the tool, a first motor including a first hollow rotor and for rotating the spindle, a second motor including a second hollow rotor and for moving the spindle in the axial direction, means for transmitting a rotation of the first hollow rotor to the spindle, and means for converting a rotation of the second hollow rotor into axial movement of the spindle. The first rotor is rotated to rotate the spindle which corotatably engages the first rotor through the transmitting means. The second rotor is rotated, and the spindle is smoothly moved axially forwardly or rearwardly by the converting means which converts rotary motion of the second rotor to axial motion of the spindle.

Abstract: A machine tool with a spindle for machining a large-diameter workpiece in that a servo motor for moving a spindle in the axial direction and a variable reluctance motor for rotating the spindle are installed in a housing, and a synchronous controller for synchronizing and driving the above-mentioned servo motor and the variable reluctance motor is provided. The variable reluctance motor has a characteristic in that a large driving torque can be obtained in a low rotating speed. By using a variable reluctance motor as a spindle motor, therefore, it is possible to obtain a large torque without providing a large size motor, and also possible to realize a large-diameter machining by a small-size unit.