Patent application number | Description | Published |
20080231129 | Spindle apparatus - In a spindle apparatus for a machine tool, a spindle is supported on a housing by support-purpose bearing devices, and is rotated by an electric motor, and a tool is attached to a tool attaching portion formed at a distal end of the spindle. A radial magnetic bearing for vibration suppressing purposes which includes a plurality of electromagnets is provided around the tool attaching portion of the spindle. A plurality of radial displacement sensors for detecting a displacement of the tool attaching portion in radial directions are provided around the tool attaching portion. There is provided an electromagnet control unit for controlling the electromagnets of the radial magnetic bearing on the basis of outputs of the radial displacement sensors so as to support the tool attaching portion in a predetermined position. | 09-25-2008 |
20080233851 | Grinding apparatus - A grinding wheel having a convex grinding surface is attached to a wheel spindle that is contactlessly supported by a casing through a controlled type axial magnetic bearing and controlled type radial magnetic bearings and that is rotated by an electric motor. A groove of a workpiece is ground by causing relative displacement of the casing. After the axial positioning of the casing is performed, the casing is radially displaced. Then, the groove is ground. The stiffness value of the axial magnetic bearing | 09-25-2008 |
20080246358 | Magnetic bearing spindle device for machine tool - The control device displaces the main shaft in the axial direction and in the radial direction within the range of the gap between the rib member of the main shaft and the axial magnetic bearing and the gap between the main shaft and the radial magnetic bearings, by controlling the attraction forces of the axial electromagnets and the radial electromagnets, whereby the main shaft can be positioned. By controlling the axial magnetic. bearing and the radial magnetic bearings, it becomes possible to freely displace only the main shaft in the axial direction and in the radial direction, and therefore, the main shaft can be positioned at high speed and with high precision. Moreover, there is no necessity of providing the feeding mechanism in which the ball screw mechanism and linear motor etc. are employed for the purpose of displacing the magnetic bearing spindle device, and hence, reduction of the production cost for the grinding apparatus can be achieved. | 10-09-2008 |
20080252161 | Magnetic bearing device and magnetic bearing spindle device - A control device includes a differential amplifying circuit for obtaining a difference between values of exciting currents (exciting voltage values) supplied to a pair of axial electromagnets and a pair of radial electromagnets, multiplying the obtained difference by coefficient times, and outputting it as the bearing load in an axial direction and a radial direction. The exciting current includes steady current supplied to the axial electromagnets and the radial electromagnets and control current which varies by the displacement of a main shaft. By supplying the steady current to the axial electromagnets and the radial electromagnets, the magnetic attraction force of the axial electromagnets and the radial electromagnets having non-linearity is linearly approximated. Accordingly, the difference between the values of the exciting currents (exciting voltages) supplied to a pair of electromagnets is obtained and is multiplied by coefficient times, thereby obtaining a value corresponding to the bearing load. | 10-16-2008 |
20090042479 | Grinding apparatus and method of controlling grinding apparatus - A grinding wheel formed on an outer peripheral surface with a grinding surface is attached to a grinding wheel spindle supported by axial active magnetic bearings and radial active magnetic bearings in a noncontact manner axially and radially and rotated by an electric motor. A casing is axially positioned and then is radially moved and a ground part of a workpiece is ground. Before the casing moves radially and the grinding wheel comes in contact with the workpiece, the stiffness value of the radial magnetic bearings is set to an initialization value lower than a value at the usual grinding time and after the grinding surface of the grinding wheel comes in contact with the workpiece, the stiffness value of the radial magnetic bearings is set to a value higher than the initialization value for grinding the workpiece. | 02-12-2009 |
20090280096 | PANCREATIC ENDOCRINE PROGENITOR CELLS DERIVED FROM PLURIPOTENT STEM CELLS - The invention provides pluripotent cells modified to overexpress Pdx1 and Ngn3. Pluripotent cells include embryonic stem cells and induced pluripotent stem cells. Methods of producing pancreatic endocrine progenitor cells from ES cells or from iPS cells by forced expression of Pdx1 and Ngn3 are provided. Pancreatic endocrine progenitor cells are useful for drug discovery and cell replacement therapy. | 11-12-2009 |
20120008960 | REMOTE CONTROL RECEIVER AND PROJECTION DISPLAY DEVICE - A remote control receiver which receives light for exercising remote control as a transmission signal, includes: a light detector which receives the transmission signal; and a guide portion which has an incidence plane to which the transmission signal is entered, and refracts the incident transmission signal from the incidence plane and directs the incident transmission signal toward the light detector. In this arrangement, the guide portion has an interface which is tapered down from the incidence plane toward the light detector. | 01-12-2012 |
20120099087 | PROJECTION DISPLAY DEVICE - A projection display device includes an opening formed in a main body cabinet; a part to be attached in the main body cabinet through the opening; a cover which covers the opening; a detector which detects closure of the cover; and a first contact part and a second contact part which contact each other when the cover is being closed, thereby to prevent the cover from being closed up to a position where the closure is detected by the detector. When the part to be attached is not attached, the first contact part is positioned on a line contacting the second contact part at closure of the cover and is capable of evacuating to a position out of the line. The projection display device further includes an evacuation part to evacuate the first contact part to the position out of the line when the part to be attached is attached. | 04-26-2012 |