JPS591808A - Dynamic pressure operated hydraulic bearing - Google Patents

Abstract

PURPOSE:To produce a large effect of dynamic pressure by forcedly feeding the fluid which is sucked by the operation of a group of fins on a rotary table into grooves on the external periphery of a shaft member. CONSTITUTION:The air which is sucked from a suction passageway 14 is swirled by the revolution of a group of fins 20 which are formed on the lower face of a rotary table 2, and carried in the direction shown by the arrow. By the operation of the group of fins 20, the fluid is further forcedly sent from the slant part 7 of a funnel-shaped groove 8 and then discharged from an outlet passageway 18 via ?-shaped grooves 22 and 23 on the external periphery of a shaft member 4 and a vertical clearance 9. In other words, the fluid which is sucked from the suction passageway 14 is forced to travel in the direction as shown by the arrow inside the funnel-shaped groove 8 by the group of fins 20. During the further travel of the fluid, a dynamic pressure is produced at the rows 22 and 23 of the ?-shaped grooves which are cut on the external periphery of the shaft 4, and then runs in the direction shown by the arrow.

Description

[Detailed description of the invention] The invention of this application relates to a hydrodynamic bearing.

In particular, it relates to dynamic pressure fluid bearings that forcibly supply air to grooves or gaps in the bearing.

There have been many types of hydrodynamic bearings in the past, but all of them have passive methods of supplying fluid to the dynamic pressure generation mechanism, and currently no method of forcibly supplying fluid into the bearing has been adopted. It is.

The invention of the present application employs a group of fins attached to a rotary table,
Fluid, such as air, is forcibly supplied to the gap between the shaft of the rotary table and the bearing body to generate dynamic pressure and support in low-speed rotation areas, maintaining high bearing rigidity. The purpose is to

A specific example of the present invention will be described below based on the accompanying drawings. A shaft portion 4 is suspended and fixed approximately at the center of the rotary table 2. The shaft portion 4 is fitted into a funnel-shaped groove 8 provided in the bearing body 6, and permanent magnets 10 and 12 having the same polarity are attached to the lower end thereof. The funnel-shaped groove 8 consists of an inlet inclined part 7 and a vertical part 9. A suction port 14 for a fluid such as air (hereinafter, fluid refers to air in this embodiment) is provided between the upper surface of the bearing body 6 and the lower surface of the rotary table 2, and a fluid inlet 14 is provided between the lower surface of the bearing body 6 and the machine table 16. Close the outlet 18. Further, on the lower surface of the rotary table 2, a plurality of 717 groups 20 are provided to protrude downward to form a circular shape around the shaft portion 4, and the fluid supplied from the suction port 14 is used to activate the fin groups 20. It is configured so that it is sent out into the funnel-shaped groove 8 in a spiral shape. Further, the shaft portion 4 located in the portion forming the vertical portion 9 of the funnel-shaped groove 8
V-shaped groove groups 22 and 23 are bored on the outer periphery of the groove. code 16
is part of the support base. Of course, electromagnets may be used instead of the permanent magnets 10 and 12.

The air sucked in from the suction E] 14 forms a spiral as the fin group 20 provided below the rotary table 2 rotates and moves in the direction of the arrow, and the fluid is forced through the operation of the fin group. Then, it is discharged from the inclined part 7 of the funnel-shaped groove 8 through the eight-shaped grooves 22 and 23 on the outer periphery of the shaft part 4 through the vertical part 9 and from the outlet 8.

That is, the fluid sucked from the suction port 14 is transferred to the fin group 20.
Forcibly inserts the Vcfm in the direction of the arrow shown in FIG.
At steps 2 and 23, dynamic pressure is generated to move in the direction of the arrow. 3, 4, and 5 show the V-shaped groove groups 22, 23.
This figure illustrates the dynamic pressure generated and the state of fluid movement. Figure 3 shows the rotational direction of the rotating shaft 4 and the V-shaped groove group 2.
2 and 23 illustrate the overall relationship with the direction of fluid movement (indicated by arrows).

FIG. 4 shows the direction of fluid movement in the individual grooves, and when the fluid enters and exits the grooves, that is, at the locations indicated by reference numerals in this figure, a large dynamic pressure is generated. Figure 5 illustrates the positional relationship between pressure distribution and fluid movement in the grooves 22 and (23). In this distribution map, this is represented by the symbol P
Simultaneously with the rotation of the rotary table 2, it is easily levitated by the action of the permanent magnets 10 and 12 of the same polarity, which are emitted in opposition. Therefore, it is possible to support the rotary table even when rotating at low speed.

FIG. 2 is another embodiment of the present invention. In this specific example, a pair of rotary tables 26f are provided at both ends of the shaft section 28, and fin groups 30, 3 are provided below, facing each other.
2 are arranged in a circular shape, and a pair of suction ports 36 and 38 are provided between the bearing body 34 and the rotary table 26 in contact with the respective fin groups 30 and 32, and a pair of suction ports 36 and 38 are provided approximately in the middle of the pair of suction ports. A discharge port 40 is provided in the bearing body 34 of the bearing body 34 . Further, a pair of funnel-shaped grooves 42 and 44 are respectively bored inside both sides of the bearing body 340, and the shaft portion 28 is rotatably inserted into the vertical groove 46 formed by these funnel-shaped grooves 42 and 44. The magnets 48 and 50 having the same polarity are mounted below the rotary table 26, and the V-shaped groove groups 54 and 56 are provided on the outer periphery of the shaft portion 28, as in the first embodiment.

Reference numeral 52 is a part of the support base. Same sentence The operation of this other specific example is the same as the first specific example explained earlier, so the explanation will be omitted.

As described above, the hydrodynamic bearing of the present invention uses the actuation of the fin group on the rotary table to forcibly supply the sucked fluid into the groove on the outer periphery of the shaft to generate a larger dynamic pressure effect and to improve bearing rigidity. It has the effect of increasing the

[Brief explanation of drawings]

FIG. 1 is a side view of a route showing a partial cross section of a specific example of the present invention. FIG. 2 is a side view of a route in partial cross section of another specific example. 3, 4, and 5 illustrate the dynamic pressure generated in the V-shaped groove group and the state of fluid movement. FIG. 3 is a perspective view illustrating the rotational direction of the rotating shaft and the moving direction of fluid in the eight-shaped groove. FIG. 4 is a route map illustrating the locations where dynamic pressure is generated in each eight-shaped groove. Figure $5 is a route map showing the relationship between fluid movement and pressure distribution in the eight-figure groove. 2 is a rotary table, 4 is a shaft portion, 6 is a bearing body, 8 is a funnel-shaped groove,
9 is a vertical part (funnel-shaped groove), 10 and 12 are magnets, 14 is an inlet, 18 is an outlet, 20 is a fin group, and 22 and 23 are V-shaped groove groups. Patent applicant Copal Electra Co., Ltd. Agent Patent attorney Eiji Kobayashi 1 Figure 10 Figure 2 Figure 3 Figure 47

Claims (1)

[Claims] ■. A dynamic pressure fluid bearing is equipped with a fin section that generates dynamic pressure by forcibly moving fluid into the groove of the shaft section and the gap between the bearing body and the shaft section as it rotates. 2. The hydrodynamic bearing according to claim 1, wherein a shaft portion provided with a rotary table is inserted into and supported in a funnel-shaped groove provided in the bearing body. 3. The dynamic pressure fluid bearing according to claim 1, wherein a group of V-shaped grooves is provided on the outer periphery of the shaft portion. 4. The dynamic pressure fluid bearing according to claim 1, wherein a pair of magnets of the same polarity are provided below the shaft portion. 5. The dynamic pressure fluid bearing according to claim 1, comprising a plurality of fins projecting from the lower surface of the rotary table so as to hang down in the direction of the funnel-shaped groove.