JP2014149056A5 - - Google Patents

Description

The bush 105 is a cylindrical member having an inner peripheral surface 123 having a diameter larger than the outer diameter of the rotating shaft 115 by a predetermined dimension. A radial bearing surface 108 that extends flush with the inner peripheral surface 123 is formed on the inner peripheral surface 123 of the bushing 105, and is formed between the radial bearing surface 108 and the radial receiving surface 112 that is the outer peripheral surface of the rotating shaft 115. A radial clearance 114 is formed. Incidentally, the radial receiving surface 11 2, extends between the rotor corners S defined by the two thrust plates 117 and the rotation shaft 115 is spaced rotation axis O direction constituting the rotor 103. The thrust receiving surface 111 extends from the rotor corner S in the outer diameter direction of the thrust plate 117 and is configured by a ring-shaped surface of the thrust plate 117.

Further, the bush 105 is provided with a thrust air supply port 135 extending in the radial direction, one end of the thrust air supply port 135 is opened at the outer peripheral surface of the bush 105, and the other end is a thrust air supply through hole 137. Communicate with. The thrust supply through hole 137 extends in the axial direction of the bush 105 (left and right direction in FIG. 3), and both end portions thereof communicate with the thrust supply groove 133, respectively. Accordingly, a compressed gas having a predetermined pressure and a predetermined flow rate supplied from a compressed gas source (not shown) is introduced into the bush 105 from the thrust supply port 135, and through the thrust supply through hole 137 and the thrust supply groove 133, The thrust porous body 131 is reached. Thus, the thrust supply groove 133, the thrust supply port 135, and the thrust supply through hole 137 constitute a thrust supply path for supplying compressed gas to the thrust porous body 131.

A modification of the above embodiment will be described below. The configuration of the static pressure gas bearing for an air spindle according to the following modified example is for the air spindle according to the embodiment except for the deformation of the radial porous body 125 and the thrust porous body 131 and the deformation of the bush 105 due to the change. is the same as the configuration of the hydrostatic gas bearing 101, if not specifically mentioned, modification achieves effects similar to the embodiments, an effect. Furthermore, a modified example to be described later will be described with reference to the drawing showing only a part corresponding to the part shown in FIG.

Further, a radial porous body 125 and the thrust porous body 131 is disposed through the partition wall portion 105a of the third bushing 1 0 5 a discharge regulating means. Accordingly, since the pores of the radial porous body 125 and the pores of the thrust porous body 131 do not communicate with each other, the compressed gas discharged from both the porous bodies 125 and 131 can be controlled independently of each other.

(Second modification)
FIG. 7 is a view corresponding to FIG. 5 and an enlarged cross-sectional view showing a portion corresponding to the V portion of FIG.
As shown in FIG. 7, the thrust region 125 a of the radial porous body 125 is exposed to the thrust clearance 113 as in the embodiment. On the other hand, the radial region 131 a of the thrust porous body 131 is in contact with the tubular region 125 b of the radial porous body 125 extending in the vicinity of the thrust gap 113. In this modification, the bush 105 is not provided with the partition wall portion 105a.

Further, according to the configuration of the thrust porous body 131 and the radial porous body 125 of this modification, unlike the second modification shown in FIG. 7, the thrust region 125a (or the radial clearance 114) facing the thrust clearance 113 is used. The thrust porous body 131 (or radial porous body 125) is disposed in each of the radial regions 131a facing each other, so that a floating force in the thrust direction (or radial direction) can be efficiently applied.
Further, since the thrust region 125a which faces the thrust gap 113 (or radial region 131a which faces the radial clearance 114) does not occur, there is no need to perform a sealing process of the thrust region 125a (or radial region 131 a), the manufacturing cost Can be reduced.

In the said embodiment and modification, although it is the structure which arrange | positions a thrust porous body and a radial porous body to a stator, this invention is not limited to this structure. Any configuration can be used as long as a thrust porous body and a radial porous body are provided on at least one of the rotor and the stator and the rotor and the stator can be separated from each other. In addition, when the thrust porous body and the radial porous body are provided on the rotor due to this change, the partition walls are provided on the rotor.

In the embodiment and the modification, the radial bearing surface 108 extends in parallel with the rotation axis O, thereby generating a floating force in the radial direction by the compressed gas, and the thrust bearing surface 107 is orthogonal to the rotation axis O. In this way, the floating force is generated in the thrust direction by the compressed gas by extending, but the present invention is not limited to this configuration. The present invention can be applied to a static pressure gas bearing for an air spindle having a configuration in which a radial bearing surface extends in a direction intersecting the rotation axis O or a configuration in which a thrust bearing surface extends without being orthogonal to the rotation axis O. Needless to say. In this case, the radial clearance or the thrust clearance extends at a predetermined angle with respect to the rotation axis O.