Abstract: In a main spindle device provided with a housing and a main spindle, a labyrinth-forming annular groove is formed, in the circumferential direction of the main spindle, on the outer circumferential surface of a protruding portion of the spindle that protrudes from the housing on the front side. A housing lid member having a protruding portion that is inserted into the labyrinth-forming annular groove so as not to contact an inside surface of the labyrinth-forming annular groove all around the periphery is fixed to the housing on the front side thereof and forms a labyrinth seal portion between the protruding portion and the labyrinth-forming annular groove. The housing lid member is constructed so that the housing lid member can be divided into at least two pieces with respect to the circumference of the labyrinth-forming annular groove.

Abstract: A main spindle device includes: a housing having an air supply passage; a spindle that is inserted into the housing and supported by a bearing so as to be able to rotate relative to the housing; and an air sealing member that is positioned between an outer circumferential surface of the spindle and the housing on a front side with respect to the bearing along a rotation axis of the spindle, has a substantially annular shape, and is detachably fixed to the housing with an inner circumferential surface of the air sealing member facing the outer circumferential surface of the spindle, wherein air supplied from the air supply source through the air supply passage is discharged into a gap between the outer circumferential surface of the spindle and the housing, thereby effecting non-contact air sealing at least between the inner circumferential surface of the air sealing member and the outer circumferential surface of the spindle.

Abstract: Information regarding various types of machining may be stored in an NC program. Therefore, by controlling preload application means on the basis of the NC program, it is possible to control an amount of preload that is applied to a rolling bearing to a preload amount that can give a spindle characteristic that meets every type of machining. Thus, highly accurate machining is possible. Then, when a preload command value falls out of range of a preload as a controllable region, the preload command value is corrected so as to fall within the range of the preload. That is, an actually controlled preload is regulated to fall within a preset range of a preload. Therefore, it is possible to ensure the stiffness of the rolling bearing or prevent heating and excessive increase in contact pressure of the rolling bearing.

Abstract: A main spindle device includes: a housing having an air supply passage; a spindle that is inserted into the housing and supported by a bearing so as to be able to rotate relative to the housing; and an air sealing member that is positioned between an outer circumferential surface of the spindle and the housing on a front side with respect to the bearing along a rotation axis of the spindle, has a substantially annular shape, and is detachably fixed to the housing with an inner circumferential surface of the air sealing member facing the outer circumferential surface of the spindle, wherein air supplied from the air supply source through the air supply passage is discharged into a gap between the outer circumferential surface of the spindle and the housing, thereby effecting non-contact air sealing at least between the inner circumferential surface of the air sealing member and the outer circumferential surface of the spindle.

Abstract: In a main spindle device provided with a housing and a main spindle, a labyrinth-forming annular groove is formed, in the circumferential direction of the main spindle, on the outer circumferential surface of a protruding portion of the spindle that protrudes from the housing on the front side. A housing lid member having a protruding portion that is inserted into the labyrinth-forming annular groove so as not to contact an inside surface of the labyrinth-forming annular groove all around the periphery is fixed to the housing on the front side thereof and forms a labyrinth seal portion between the protruding portion and the labyrinth-forming annular groove. The housing lid member is constructed so that the housing lid member can be divided into at least two pieces with respect to the circumference of the labyrinth-forming annular groove.

Abstract: A semi-contact guide apparatus includes a bed as a first member, a column as a second member, a plural number of oil-hold portions and an oil-supply device. The column is movably guided on the bed. A sliding surface is formed on the column. The plural number of oil-hold portions is formed on the sliding surface. Dimensions of the oil-hold portions are defined according to load distribution of the weight of the column. The oil-supply device supplies lubricant oil to the oil-hold portions. The amount of lubricant oil supplied to the oil-hold portion is defined according to each of dimensions of the oil-hold portions. Since the dimensions such as areas of the oil-hold portions and the amount of the lubricant oil supplied to the oil-hold portion are defined as above, inclination of the column on the bed is prevented, and the column can be smoothly moved on the bed.

Abstract: A semi-contact guide apparatus includes a bed as a first member, a column as a second member, a plural number of oil-hold portions and an oil-supply device. The column is movably guided on the bed. A sliding surface is formed on the column. The plural number of oil-hold portions is formed on the sliding surface. Dimensions of the oil-hold portions are defined according to load distribution of the weight of the column. The oil-supply device supplies lubricant oil to the oil-hold portions. The amount of lubricant oil supplied to the oil-hold portion is defined according to each of dimensions of the oil-hold portions. Since the dimensions such as areas of the oil-hold portions and the amount of the lubricant oil supplied to the oil-hold portion are defined as above, inclination of the column on the bed is prevented, and the column can be smoothly moved on the bed.

Abstract: A machine tool having a grinding wheel for grinding a workpiece mounted on a table. The machine tool is provided with a truing apparatus for truing the grinding wheel and a measuring device for measuring the diameter of the grinding wheel after every truing operation. Both of the truing apparatus and the measuring device are mounted on a movable base. The movable base is moved between its retract position at the outside of the table and a forward position above the table. The movable base is move to the forward position to bring the truing apparatus and the touch sensor into predetermined positions for truing and measuring operations. After the truing and measuring operations, the movable base is moved away from the table and is retracted to its retract position. The truing apparatus is provided with a truer support shaft whose rotational shaft intersects with a horizontal plane with an angle of 45.degree., and a truer attached to the truer support shaft.

Abstract: A thermal displacement compensating apparatus capable of compensating for the thermal displacement of the main spindle of a machine tool is disclosed. A feed back scale and a measuring head are provided in order to detect the actual position of the front end portion of the spindle head. Furthermore, a distance sensor is provided for detecting the thermal extension of the main spindle with respect to the spindle head. The output signal from the distance sensor is used for modifying the present position detected by the measuring head or modifying a commanded target position. With this arrangement, a tool attached to the front end portion of the main spindle is moved to the commanded position regardless of the thermal displacement of the spindle head and the main spindle.

Abstract: A pallet changer including an arcuate clamp rail adapted to engage and support a pallet slidably, the arcuate clamp rail being provided in a work table in a machining center, and a plurality of arcuate support rails adapted to engage and support pallets slidably, the arcuate support rails being provided on a pallet pool so that they can be indexed to a pallet changing position. The support rail indexed to the pallet changing position completes a circular track for pallet conveyance conjointly with the clamp rail. Further, a swivel arm is disposed for rotation between the work table and the pallet changing position, the swivel arm being provided at both ends thereof with engaging hooks each capable of engaging an engaging block of each pallet disengageably. By the rotation of the swivel arm, two pallets are exchanged simultaneously along the above circular track between the work table and the pallet changing position.

Abstract: A tool holder incorporating a tool position compensating mechanism is disclosed, which includes a screw shaft axially slidably but non-rotatably supported in a tool mounting shell and formed with a cam surface. A rotary member is rotatably received and threadedly engaged with the screw shaft. A ring shaped internal gear and a reduction gear device including a planet gear are arranged to transmit rotation of a tool spindle to the rotary member at a predetermined reduction gear ratio. When rotated, the rotary member moves the screw shaft in the axial direction which causes adjustment of a tool position in the radial direction by the wedging action of the cam surface.

Abstract: A tool holder incorporating a tool position compensating mechanism which comprises a screw shaft rotatably supported in a tool mounting shell in axial alignment therewith and engageable with a stationary member on a machine tool for relative rotation with the mounting shell is disclosed. A sleeve is threadedly engaged with the screw shaft to be axially moved at the time of relative rotation between the mounting shell and the screw shaft. This sleeve, when axially moved, actuates a transmitting member, supported in the shell, by the wedge action of a cam surface formed thereon, so that a cutting blade support end of a tool secured on the mounting shell is bent to adjust the position of a cutting blade on the tool.