A guiding apparatus having a slider supported in a floating manner above a base by means of hydrostatic bearings, a pressurized fluid supplying means for supplying the hydrostatic bearings with a pressurized fluid, and detecting means for detecting the displacement of the slider with respect to a designated coordinate. The pressure of the pressurized fluid from the pressurized fluid supplying means is adjusted in accordance with a signal which is obtained as a result of the comparison between the value representing the reference position of the slider with respect to the base and the value actually measured by the detecting means, thereby adjusting the sizes of the gaps for forming hydrostatic fluid film for the hydrostatic bearings, thereby to correct the position of the slider to the designated position. With this arrangement, the absolute position of the slider is precisely determined without being affected by disturbance factors such as the precision of assembling of the base and the slider. This guiding apparatus is suited to use as precision positioning apparatus such as that used in the assembly of photomodule elements.
A positioning table assembly includes a table slidably mounted on a pair of guide rails. The table is divided into a central section and a peripheral section which are connected through a connecting section. A traction shaft of a drive motor extends through a center slot formed in the central section. A piezoelectric device is mounted on the table to displace the central section relative to the peripheral section. When the piezoelectric device is energized, the central section is displaced to establish a frictional contact between the traction shaft in rotation and the central section so that the table may move in either direction depending on the direction of rotation of the traction shaft.
A bolt insertion hole is provided along an edge end portion on a flat surface of a plate-like member, and a tap hole is provided on an end face of the other edge end correspondingly to the bolt insertion hole. A bolt is inserted into the bolt insertion hole and screwed with the tap hole, and a box bearing is formed by means of four plate-like members joined together. The diameter of the bolt insertion hole is made larger than the diameter of the bolt. By changing the insertion position of the bolt with respect to the bolt insertion hole, the distance of a bearing gap inside the bearing, which is formed into the shape of a box, can be adjusted.
A hydrostatically supporting device for slide wherein a first slide member is provided with four guide surfaces constituting a square guide bore, and a second slide member having a square cross section is mated with the first slide member for sliding movements therebetween. Each of guide surfaces is provided with a pair of hydrostatic supporting surfaces formed at longitudinal ends of the guide surfaces, respectively, and each hydrostatic supporting surface is formed with a first hydrostatic pressure pocket formed at lateral center of the hydrostatic supporting surface and extending in the sliding direction. This first hydrostatic pressure pocket is provided with an oil supplying nozzle for supplying pressurized oil therethrough. Further, the hydrostatic supporting surface is provided with a pair of second hydrostatic pressure pockets each formed at opposite lateral ends of the hydrostatic supporting surface and extending in the sliding direction, and a pair of connecting grooves formed between the first and second hydrostatic pressure pockets for introducing the oil to the second hydrostatic pressure pockets.
6149306 - Sliding bearing - Owned by C.R.I.D. S.A. Compagnie de Recherches Industrielle et Developpements (Rennaz,CH)
Air flows are produced in a sliding bearing between the bearing surfaces (L) sliding relative to one another of a movable body (1, 3) and a stationary body (2). Compressed air is expanded through nozzles (4) between the bearing surfaces (L) to atmospheric pressure. As a result of these air flows, the static pressure between the bearing surfaces (L) is reduced so that compressive forces acting between the moving and the stationary body are produced. The bearing surfaces (L) and air flows are so matched to one another that the movable body (1, 3) is in a force-free state of equilibrium on assuming a position in which the bearing surfaces (L) of the movable body (1, 3) are not in contact with the bearing surfaces (L) of the stationary body (2). In order to ensure a clearly defined equilibrium position, the clearance between the movable body (1, 3) and the stationary body (2) is chosen so that any possible change of the spacings between the bearing surfaces brings about an opposing change of the pressure ratios. Spacings of approximately 0.01 to 0.02 mm are suitable for air flows. So that the sliding bearing can absorb external forces, the bearing surfaces are enlarged for increasing the compressive forces. The sliding bearing is virtually free from friction and free from wear. It is suitable for the bearing or seating of machine parts moved in rotary or linear manner, such as for the seating of spindles in machine tools.
A positioning device includes a table (101, 213) guided by a carriage (15, 199), the carriage (15, 199) being displaceable in two coordinate directions (X, Y) with respect to the base (3) and the table (101, 213) being displaceable with respect to the carriage (15, 199) in the same coordinate directions (X, Y) solely by Lorentz forces, while in a third coordinate direction (Z) the position of the table (101, 213) is determined by a static gas bearing. The two-step positioning device is particularly suitable for use in opto-lithographic devices.
