JPH0510824U - Air bearing - Google Patents

Abstract

(57) [Abstract] [Purpose] To easily improve the rotation accuracy of the rotating body without further improving the processing accuracy of the rotating body. Structure: A plurality of variable throttle valves 20, 20 ... A plurality of passages 14A, 14B, 14 formed in a cylindrical bearing body
It is arranged outside the bearing main body 11 so as to communicate with C and 14D independently and to be operated externally. Therefore, since the variable throttle valves 20, 20 ... Can be adjusted from the outside of the bearing body 11 to bring the rotating shape of the rotating body 30 close to a perfect circle, the rotating accuracy of the rotating body 30 can be easily increased. ..

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to an air bearing, and more particularly, to an air bearing in which a rotating body disposed in a cylindrical bearing body rotates in contact with the bearing body.

[0002]

[Prior Art]

 The air bearing produces a fluid resistance in the compressed air through a throttle formed in the bearing portion to obtain bearing rigidity. Bearing rigidity increases as the throttle diameter decreases and the fluid resistance increases. This air bearing is formed in a cylindrical shape, and the rotor fitted in the cylindrical shape rotates in a non-contact state with the cylindrical bearing due to the rigidity of the air bearing.

The rotational accuracy of the rotor is affected by the processed shape of the rotor. That is, the rotor arranged in the air bearing rotates in a constant trajectory according to the shape of the processed rotor. On the other hand, recent measuring machines are required to have high measurement accuracy, and for example, a roundness measuring machine using a rotor of an air bearing as a rotary table is applicable. In order to improve the measurement accuracy of this roundness measuring machine, it is necessary to improve the rotation accuracy of the rotor, and in order to improve the rotation accuracy of the rotor, it is necessary to reduce the machining error of the rotor.

[0004]

[Problems to be solved by the device]

 However, it is difficult to improve the machining accuracy of the rotor because the performance of the machining equipment is limited. Therefore, there is a problem that it is difficult to improve the rotational accuracy of the rotor. The present invention has been made in view of such circumstances, and an object of the present invention is to provide an air bearing that can easily improve the rotational accuracy of the rotor.

[0005]

[Means for Solving the Problems]

 According to the present invention, a passage is communicated with a plurality of discharge ports formed in an inner circumference of a cylindrical bearing body, and compressed air supplied to the passage is discharged from the discharge ports to obtain bearing rigidity, thereby improving the shaft rigidity. In an air bearing for rotating a rotating body disposed in a receiving main body in a non-contact state with the bearing main body, a variable throttle means is provided in each of the passages and is provided outside the bearing main body so as to be externally operated. It is characterized by being arranged.

[0006]

[Action]

 According to the present invention, the variable throttle means is provided in the plurality of passages formed in the cylindrical bearing body and is arranged outside the bearing body so as to be externally operated. Therefore, after setting the variable throttle means so that the pressure in each passage is the same, it is possible to adjust the variable throttle means from outside the bearing body so that the shape of the rotational accuracy of the rotor approaches a perfect circle. it can.

[0007]

【Example】

 The air bearing according to the present invention will be described in detail below with reference to the accompanying drawings. FIG. 1 shows a sectional view of an air bearing 10 according to the present invention, and FIG. 2 shows an outline view of the air bearing 10 according to the present invention. A bearing main body 11 of the air bearing 10 is formed in a cylindrical shape, and eight compressed air passage systems 14 are formed inside the bearing main body 11. The passage system 14 comprises passages 14A, 14B, 14C, 14D. The discharge ports 16A, 16B, 16C, 16D are in communication with the tip ends of the respective passages 14A, 14B, 14C, 14D. The discharge ports 16A and 16B are formed on the inner peripheral surface of the bearing body 11, and the discharge ports 16C and 16D are formed on the upper surface and the lower surface of the bearing body 11, respectively.

Further, the rear ends of the passages 14A, 14B, 14C and 14D are in communication with the pipes 18, 18, 18 and 18. The pipes 18, 18, 18, 18 are provided with variable throttle valves 20, 20, 20, 20, respectively. As a result, the variable throttle valves 20, 20, 20, 20 are provided outside the air bearing 10 so that they can be operated externally, and are further connected to the eight passage systems 14 via the pipes 18, 18. There is.

Further, a supply source of compressed air (not shown) is connected to the pipes 18, 18. Therefore, the compressed air supplied from this supply source is discharged from the discharge ports 16A, 16B, 16C, 16D through the variable throttle valves 20, 20, ..., The passages 14A, 14B, 14C, 14D and the like. The compressed air discharged from the discharge ports 16A and 16B obtains radial bearing rigidity, and the compressed air discharged from the discharge ports 16C and 16D obtains thrust bearing rigidity.

A rotor 30 is rotatably arranged on the air bearing 10. The rotor 30 has a shaft 30A, and disk-shaped plates 30B and 30B are fixed to the upper and lower ends of the shaft 30A. When the air bearing 10 is used in a roundness measuring machine, the upper plate 30B serves as a rotary table. An object 32 to be measured is placed on the rotary table 30B, and a tip terminal 34 is in contact with the peripheral surface of the object 32 to be measured.

Incidentally, FIG. 3 shows the outer shape of the shaft 30 A of the rotor 30, and FIG. 4 shows the rotation accuracy 32 of the rotor 30 by the air bearing 10. The rotation accuracy 32 has the same shape when the outer shape of the shaft 30A is the same. The operation of the air bearing 10 according to the present invention constructed as above will be described.

First, the variable throttle valves 20, 20 ... Connected to the eight passage systems 14 are set to the same throttle pressure. That is, the variable throttle valves 20, 20 ... Are set so that the pressure in each passage is measured by a pressure gauge. Next, based on the rotational accuracy shape 32 of the rotor 30 shown in FIG. 4, the variable throttle valves 20, 20 ... Are adjusted so as to approach the rotational accuracy shape 3211114 at locations outside the perfect circle 34. Next, the variable throttle valves 20, 20 ... Are locked. This completes the adjustment of the variable throttle valves 20, 20 ...

Although the variable throttle valve 20 is used in the above embodiment, the present invention is not limited to this, and other variable throttle means may be used.

[0014]

[Effect of the device]

 As described above, according to the air bearing of the present invention, after the variable throttle means is set so that the pressures in the respective passages are the same, the bearing is configured so that the shape of the rotational accuracy of the rotating body approaches a perfect circle. The variable diaphragm means can be adjusted from the outside of the main body. Therefore, the rotation accuracy of the rotating body can be easily increased without further increasing the processing accuracy of the rotating body.

Further, even if it is not possible to machine a plurality of rotating bodies into the same shape, it is possible to easily increase the rotational accuracy of the rotating bodies by adjusting the variable diaphragm means in accordance with each processed shape.

[Brief description of drawings]

FIG. 1 is a sectional view of an air bearing according to the present invention.

FIG. 2 is an external view of an air bearing according to the present invention.

FIG. 3 is a cross-sectional view showing the outer shape of the rotor shaft used in the air bearing according to the present invention.

FIG. 4 is a diagram showing the rotational accuracy of the rotor used in the air bearing according to the present invention.

[Explanation of symbols]

 10 ... Air bearing 11 ... Bearing main body 14A, 14B, 14C, 14D ... Passage 16A, 16B, 16C, 16D ... Discharge port 20 ... Variable throttle valve 30 ... Rotor

Claims (1)

[Claims for utility model registration] [Claim 1] A passage is connected to a plurality of discharge ports formed in the inner periphery of a cylindrical bearing body, and the compressed air supplied to the passages is discharged from the discharge ports. In an air bearing that obtains bearing rigidity by rotating the rotating body disposed in the bearing body in a non-contact state with the bearing body, variable throttle means is provided in each of the passages and is externally operable. The air bearing is arranged outside the bearing body.