Abstract: A stator including, a stator core having a slot, a winding wire to be inserted into the slot; and an insulation sheet interposed between the slot and the winding wire and configured to electrically insulate an inner wall of the slot and the winding wire, wherein the insulation sheet includes an insulation paper, a first adhesive layer disposed on a front surface of the insulation paper facing the inner wall of the slot, and a second adhesive layer disposed on a back surface of the insulation paper facing the winding wire, a foaming adhesive to be thermally cured while foaming by heating is disposed on the first adhesive layer, and a non-foaming adhesive having lower viscosity than that of the foaming adhesive when unheated is disposed on the second adhesive layer.

Abstract: A grinding wheel is manufactured such that (a) any one of particles for an abrasive grain layer and particles for a substrate layer are put into the press-mold die, and other particles are put onto the particles in the press-mold die, and then the substrate layer and the abrasive grain layer are integrally press-molded to form a non-baked grinding chip with an arcuate shape; (b) depressions are formed on the abrasive grain layer of the non-baked grinding chip; (c) the grinding chip on which the depressions are formed is baked; and (d) the plurality of baked-grinding chips are adhered to a core of the grinding wheel.

Abstract: In a manufacturing method for a grinding wheel in which a plurality of wheel chips each composed of an abrasive grain layer containing superabrasive grains and a foundation layer are adhered to a core attached to a wheel spindle carried by a wheel head of a grinding machine to be drivingly rotatable about a rotational axis and in which a grinding surface formed on the abrasive grain layers grinds a workpiece, drivingly rotatably supported by a workpiece support device of the grinding machine, in contact at a grinding point, the method forms green wheel chips each having opposite ends in a wheel circumferential direction inclined relative to the wheel circumferential direction, bakes the green wheel chips to form baked wheel chips, and adheres the plurality of baked wheel chips to the core so that an oblique groove is formed between adjoining abrasive grain layers.

Abstract: In a manufacturing method for a grinding wheel in which a plurality of wheel chips each composed of an abrasive grain layer containing superabrasive grains and a foundation layer are adhered to a core attached to a wheel spindle carried by a wheel head of a grinding machine to be drivingly rotatable about a rotational axis and in which a grinding surface formed on the abrasive grain layers grinds a workpiece, drivingly rotatably supported by a workpiece support device of the grinding machine, in contact at a grinding point, the method forms green wheel chips each having opposite ends in a wheel circumferential direction inclined relative to the wheel circumferential direction, bakes the green wheel chips to form baked wheel chips, and adheres the plurality of baked wheel chips to the core so that an oblique groove is formed between adjoining abrasive grain layers.

Abstract: In a wheel spindle device wherein a plurality of grinding wheels are attached in a juxtaposed relation to a wheel spindle rotatably carried on a wheel head of a grinding machine, a reference position for specifying a position in the circumferential direction of the grinding wheel is provided on a core member of each of the grinding wheels, and a plurality of inclined grooves at predetermined angular intervals are formed on a grinding surface of each grinding wheel to be inclined relative to the circumferential direction of each grinding wheel. In order that the fluctuations in the dynamic pressure and the grinding resistance between respective grinding wheels and workpiece portions ground therewith do not grow as a combined or synergy effect, the inclined grooves on each grinding wheel are shifted in angular phase from those on another grinding wheel, so that grinding efficiency and accuracy can be enhanced.

Abstract: In a grinding wheel in which abrasive tips for rough grinding and abrasive tips for finish grinding are alternately bonded to a periphery of a disk type base rotating about a rotation axis, each abrasive tip includes the abrasive layer formed by bonding abrasive grains and a lower layer overlaid and integrally for led with the abrasive layer. The abrasive tip is attached to the periphery of the base at the lower layer. A Young's modulus of the lower layer of the abrasive tip for finish grinding relative to a load acting on the grinding surface of the abrasive tip in an inward direction of the grinding wheel is less than that of the abrasive tip for rough grinding. Thereby, the surface of a workpiece can be both rough-ground and finish-ground with superhigh-precision surface roughness with using one grinding wheel.

Abstract: A grinding wheel is manufactured such that (a) any one of particles for an abrasive grain layer and particles for a substrate layer are put into the press-mold die, and other particles are put onto the particles in the press-mold die, and then the substrate layer and the abrasive grain layer are integrally press-molded to form a non-baked grinding chip with an arcuate shape; (b) depressions are formed on the abrasive grain layer of the non-baked grinding chip; (c) the grinding chip on which the depressions are formed is baked; and (d) the plurality of baked-grinding chips are adhered to a core of the grinding wheel.

Abstract: In a wheel spindle device wherein a plurality of grinding wheels are attached in a juxtaposed relation to a wheel spindle rotatably carried on a wheel head of a grinding machine, a reference position for specifying a position in the circumferential direction of the grinding wheel is provided on a core member of each of the grinding wheels, and a plurality of inclined grooves at predetermined angular intervals are formed on a grinding surface of each grinding wheel to be inclined relative to the circumferential direction of each grinding wheel. In order that the fluctuations in the dynamic pressure and the grinding resistance between respective grinding wheels and workpiece portions ground therewith do not grow as a combined or synergy effect, the inclined grooves on each grinding wheel are shifted in angular phase from those on another grinding wheel, so that grinding efficiency and accuracy can be enhanced.

Abstract: In a grinding wheel in which abrasive tips for rough grinding and abrasive tips for finish grinding are alternately bonded to a periphery of a disk type base rotating about a rotation axis, each abrasive tip includes the abrasive layer for ed by bonding abrasive grains and a lower layer overlaid and integrally for led with the abrasive layer. The abrasive tip is attached to the periphery of the base at the lower layer. A Young's modulus of the lower layer of the abrasive tip for finish grinding relative to a load acting on the grinding surface of the abrasive tip in an inward direction of the grinding wheel is less than that of the abrasive tip for rough grinding.

Abstract: First and second end surface truing sections are formed by protruding cylindrical first and second base bodies from opposite end surfaces of a disc-like base of an opposite end surface truing tool in the axial direction thereof and by providing on the external surface of the first base body and the internal surface of the second base body first and second abrasive grain layers in which numerous diamond abrasive grains are adhered with bond material. The rotational axis of the opposite end surface truing tool is inclined relative to the rotational axis of the grinding wheel within almost the same plane at a predetermined inclination angle.

Abstract: First and second end surface truing sections are formed by protruding cylindrical first and second base bodies from opposite end surfaces of a disc-like base of an opposite end surface truing tool in the axial direction thereof and by providing on the external surface of the first base body and the internal surface of the second base body first and second abrasive grain layers in which numerous diamond abrasive grains are adhered with bond material. The rotational axis of the opposite end surface truing tool is inclined relative to the rotational axis of the grinding wheel within almost the same plane at a predetermined inclination angle.

Abstract: An abrasive tool includes an electroformed layer having superabrasive grains electroplated on an outer surface of the electroformed layer, and a plurality of dimples arranged on the outer surface of the electroformed layer using a mold with projections made of gel adhesive. The concentration of the abrasive gains is regulated by changing the number of the dimples (i.e., changing a dimple-area-rate). The gel adhesive preferably has a viscosity of 500,000 cP or smaller. The dimple-area-rate is preferably from 7 to 70%.

Abstract: A grinding wheel comprising abrasive grains, a bonding material for bonding the abrasive grains, and grain clusters of accumulated filler grains having a size smaller than the abrasive grains. The grinding wheel may be a vitrified grinding wheel, and in this case, chromium oxide having good affinity with the vitrified bonding material may be used as the filler grains.

Abstract: A grinding wheel is for use in a grinding machine, and is attached on a wheel spindle of the grinding machine for simultaneously grinding at least two parts of a workpiece. The grinding wheel includes at least two wheel cores. Each of wheel cores has a disk-like shape. An abrasive layer is disposed on a circumferential surface of each of the wheel cores. A spacer portion is inseparably fixed on at least one of the wheel cores for keeping a space between the abrasive layers of the wheel cores. And a first labyrinth portion located on one of side surfaces of one of the wheel cores for forming a labyrinth seal with a second labyrinth portion arranged on the grinding machine. The number of separable parts of the grinding wheel are extremely decreased in consideration of imbalance of every part. The spacer portion is integral with at least one of the wheel cores.

Abstract: A workpiece and a grinding wheel are rotated and the grinding wheel is moved in a direction parallel to the rotational axis of the workplace so as to grind a cylindrical surface of the workpiece. After a part of the cylindrical surface is ground, a rest device is advanced towards the workpiece so as to support the part of the cylindrical surface of the workpiece which has been ground. Under the condition, the remaining portion of the cylindrical surface of the workpiece is ground.

Abstract: A grinding wheel for grinding a workpiece has a first grinding surface and a second grinding surface successive thereto. The first and second grinding surfaces are parallel to and inclined with respect to the rotational axis of the workpiece, respectively. A diameter of the workpiece to be ground in a next grinding operation is measured in advance. An angle to be formed between the second grinding surface and the rotational axis of the workpiece is selected based upon the measured diameter of the workpiece. The selected angle is established between the second grinding surface and the rotational axis of the workpiece. The grinding wheel is moved relative to the workpiece in a direction of the rotational axis of the workpiece, whereby the cylindrical surface of the workpiece is firstly ground by the second grinding surface and subsequently ground by the first grinding surface of the grinding wheel.

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 method and apparatus for grinding a cylindrical surface of a workpiece by a traverse movement of a grinding wheel having a relatively narrow grinding surface. To improve the cylindricity of cylindrical surface, the traverse grinding is divided into a rough traverse grinding and a finish traverse grinding. In the rough traverse grinding, a traverse girding is carried out with a large depth of cut which would causes a deterioration of the cylindricity at one end of the cylindrical surface. In the finish traverse grinding, a traverse girding is carried out with a small depth of cut to improve the cylindricity. In another embodiment, one of grinding conditions such as the traverse speed of the grinding wheel, the rotational speed of the workpiece and the peripheral speed of the grinding wheel is changed when the grinding wheel approaches an end of the cylindrical surface at which the traverse grinding ends so as to make the grinding force constant, thereby improving the cylindricity of the cylindrical surface.

Abstract: A grinding wheel for use in a grinding machine, wherein a plurality of grinding tips are bonded on the periphery of a wheel core having a disk-like shape using a bond which forms a bonding layer between the wheel core and the grinding tips. The grinding wheel is further provided with means for preventing coolant from entering inside of the abrasive layer and/or bonding layer, thereby preventing the bonding layer from being swelling by the coolant. In a first embodiment, the preventing means is composed of rubber layers formed on the both side surfaces of the grinding wheel at the places corresponding to the radial position of the bonding layer. In another embodiment, the preventing means is composed of water-repellant material capable of repelling water. Such material is composed of silicon or fluorine resin and is soaked into the grinding tips.

Abstract: A grinding wheel which is formed from super hard abrasive grains is trued by traverse-feeding a truing tool a plurality of times (n). Among the (n) traverse feeds of the truing tool, every traverse feed except for the final (i.e., from the first to the (n-l)th traverse feed) is carried out with an infeed which is set at a relatively small value in order to remove any deflection of the grinding wheel. In the final traverse feed, the infeed of the truing tool is set at a relatively large value in order to form an excellent cutting edge on the grinding wheel. Accordingly, any deflection of the grinding wheel is removed by a plurality of traverse feeds of the truing tool carried out with a relatively small infeed, and a cutting face having an excellent cutting ability is formed on the grinding wheel by the final traverse feed carried out with a relatively large infeed.