JPS634822Y2 - - Google Patents

Description

[Detailed Description of the Invention] This invention relates to an improvement of a hydrodynamic groove bearing device comprising a hydrodynamic radial groove bearing and a hydrodynamic thrust groove bearing.

As shown in FIG. 1, in a conventional hydrodynamic groove bearing device, a housing 1 has a radial bearing surface 3 provided on the inner peripheral surface and a thrust bearing surface 5 provided on the side surface close to each other. The shaft member 7 disposed on the inner circumference of the housing 1 has a radial bearing clearance 9 on the radial bearing surface 3.
The thrust bearing surface 15 has a radial bearing surface 11 that faces the thrust bearing surface 5 and a thrust bearing surface 15 that faces the thrust bearing surface 5 with a thrust bearing clearance 13 in between. A herringbone groove 17 for a radial bearing is provided in the radial bearing surface 11, and a bent portion 19 of this herringbone groove is located at the center of the radial bearing clearance 9 in the axial direction. As shown in FIG. 2, the thrust bearing surface 15 is provided with a herringbone groove 21 for the thrust bearing, and the bent portion 23 of this herringbone groove is located at the center of the thrust bearing clearance 13 in the radial direction. . Grease is present in the radial bearing clearance 9 and the thrust bearing clearance 13, respectively.

Therefore, when the shaft member 7 rotates, the area of the boundary 25 between the radial bearing clearance and the thrust bearing clearance becomes negative pressure, as shown in FIGS. 3 and 4.
Air bubbles in the grease tend to accumulate in the boundary area 25 between the radial bearing clearance and the thrust bearing clearance. When air bubbles accumulate in the boundary area 25 between the radial bearing clearance and the thrust bearing clearance, the dynamic torque of the bearing fluctuates, radial vibration and axial vibration occur, and furthermore, the shaft member 7
If it was rotated for a long time, air bubbles would concentrate and cause poor lubrication.

The object of this invention is to provide a hydrodynamic groove bearing device that prevents the generation of air bubbles in the boundary area between the radial bearing clearance and the thrust bearing clearance.

The basic structure of this invention is that the radial bearing surface provided on the inner circumference of the housing and the thrust bearing surface provided on the side surface are close to each other, and the shaft member disposed on the inner circumference of the housing is radially aligned with the radial bearing surface. The radial bearing surface has a radial bearing surface that faces each other through a bearing clearance, and the thrust bearing surface has a thrust bearing surface that faces each other through a thrust bearing clearance, and a dynamic pressure for the radial bearing is applied to at least one of the radial bearing surface and the radial bearing surface. In the hydrodynamic groove bearing device, the groove for generating dynamic pressure is provided in at least one of the thrust bearing surface and the thrust bearing surface, and the groove for generating dynamic pressure for the thrust bearing is provided in at least one of the housing and the shaft member. This is because the boundary between the bearing clearance and the thrust bearing clearance is provided with a communicating hole that communicates with the atmosphere.

Next, an embodiment of this invention will be described based on the drawings. FIG. 5 shows a spindle using the hydrodynamic groove bearing device of this invention. The housing 31 is composed of an outer cylinder 33 and a sleeve 35 fitted and attached to the inner peripheral surface of the outer cylinder 33. Housing 31
A cylindrical radial bearing surface 37 provided at the upper end of the inner circumferential surface and a planar thrust bearing surface 39 provided at the upper side surface are closely connected. A shaft member 41 disposed on the inner periphery of the housing 31 includes a shaft 43 passing through the inner periphery of the housing 31 and an upper annular member 45 fitted and attached to the upper part of the shaft 43.
Lower annular member 47 fitted and attached to the lower part of the
It is composed of. The shaft member 41 has a cylindrical radial bearing surface 51 facing the radial bearing surface 37 with a radial bearing clearance 49 in between, and a planar thrust bearing surface 55 facing the thrust bearing surface 39 with a thrust bearing clearance 53 in between. have.
A herringbone groove is provided in the radial bearing surface 51 as a groove 57 for generating dynamic pressure for the radial bearing, and a bent portion 59 of this herringbone groove is provided.
is located closer to the thrust bearing clearance 53 than the axial center of the radial bearing clearance 49, that is, on one side. As shown in FIG. 6, the thrust bearing surface 39 is provided with a herringbone groove as a groove 61 for generating dynamic pressure for the thrust bearing, and the bent portion 63 of this herringbone groove extends in the radial direction of the thrust bearing clearance 53. It is located on the radial bearing clearance 49 side, that is, on one side, from the center of the radial bearing gap 49. An axial groove is provided on the inner circumferential surface of the upper annular member 45, and the boundary portion 65 between the radial bearing clearance and the thrust bearing clearance forms a communication hole 67 communicating with the atmosphere. An outer circumferential groove 69 is provided on the outer circumferential portion of the thrust bearing surface 39, and the upper annular member 4
The outer peripheral surface of the housing 31 faces the inner peripheral surface of the housing 31 with a seal gap 71 in between. The housing 31 has a lower radial bearing surface 73 provided at the lower end of the inner peripheral surface and a thrust bearing surface 7 provided at the lower side surface.
5 are close to each other, and the shaft member 41 has a lower radial bearing surface 79 that faces the lower radial bearing surface 73 with a lower radial bearing clearance 77 in between, and a lower thrust bearing surface 75 that faces the lower radial bearing surface 73 with a lower thrust bearing clearance 8 in between.
1 and a lower thrust receiving surface 83 which faces each other through the lower thrust receiving surface 83 . A herringbone groove is provided in the lower radial bearing surface 79 as a groove 85 for generating dynamic pressure for the lower radial bearing, and a bent portion 87 of this herringbone groove is formed in the axial direction of the lower radial bearing clearance 77. It is located on the thrust bearing clearance 81 side below the center portion. A herringbone groove is provided in the lower thrust bearing surface 75 as a groove 88 for generating dynamic pressure for the lower thrust bearing, and although the bent portion of this herringbone groove is not shown, it forms the lower thrust bearing clearance. It is located on the radial bearing clearance 77 side below the radial center of the bearing 81 . An axial groove is provided in the inner circumferential surface of the lower annular member 47, and the boundary portion 89 between the lower radial bearing clearance and the lower thrust bearing clearance serves as a lower communication hole 91 communicating with the atmosphere. There is. An outer circumferential groove 93 is provided on the outer circumferential portion of the lower thrust bearing surface 75, and the outer circumferential surface of the lower annular member 47 faces the inner circumferential surface of the housing 31 via a lower seal gap 95. A radial bearing surface 37 and a lower radial bearing surface 7 are provided on the inner peripheral surface of the housing 31.
3 is provided with an inner circumferential groove 97, and this inner circumferential groove 97 is connected to the communication hole 9 provided in the housing 31.
9 communicates with the atmosphere. Said outer circumferential groove 6
9. Lubricants such as grease or lubricating oil are present in the thrust bearing clearance 53, radial bearing clearance 49, inner groove 97, lower radial bearing clearance 77, lower thrust bearing clearance 81, and lower outer groove 93. are doing. The hydrodynamic groove bearing device located above is symmetrical with respect to the hydrodynamic groove bearing device located below, and although not shown, a VTR rotating head is provided at the upper end of the shaft member 41. A rotary cylinder is attached to the rotor, and the rotor of the motor is attached to the lower end.

When the shaft member 41 rotates with the above configuration,
The pressure of the fluid in the radial bearing clearance 49 is increased by the pumping action of the dynamic pressure generating groove 57 for the radial bearing, and the radial bearing surface 51 rotates without contacting the radial bearing surface 37. Further, due to the pumping action of the dynamic pressure generating groove 61 for the thrust bearing, the pressure of the fluid in the thrust bearing clearance 53 increases, and the thrust bearing surface 55 rotates without contacting the thrust bearing surface 39. In this case, since the boundary 65 between the radial bearing clearance and the thrust bearing clearance communicates with the atmosphere, the area of the boundary 65 between the radial bearing clearance and the thrust bearing clearance has negative pressure as shown in FIGS. 7 and 8. No. Figure 7 is a chart showing the pressure distribution of fluid in the radial bearing clearance.
FIG. 8 is a chart showing the pressure distribution of the fluid in the thrust bearing clearance, and the pressure of the fluid in the radial bearing clearance 49 and the fluid pressure in the thrust bearing clearance 53 at the initial stage of rotation of the shaft member 41 are both shown by dotted lines. The fluid pressure in the radial bearing clearance 49 and the fluid pressure in the thrust bearing clearance 53 when the shaft member 41 is in a stable rotational state are both shown by solid lines. The dynamic pressure generating groove 57 for the radial bearing is a herringbone groove, and the bent portion 59 of this herringbone groove is
is located closer to the thrust bearing clearance 53 than the center of the radial bearing clearance 49 in the axial direction, so air bubbles that have entered the radial bearing clearance 49 during assembly of the bearing device move toward the thrust bearing clearance 53 when the shaft member 41 rotates. , are discharged to the outside from the communication hole 67. The groove 61 for generating dynamic pressure for the thrust bearing is a herringbone-shaped groove, and the bent portion 63 of this herringbone-shaped groove is located on the radial bearing clearance 49 side from the radial center of the thrust bearing clearance 53. Air bubbles that entered the thrust bearing clearance 53 during the assembly of the bearing device are removed from the shaft member 41.
When it rotates, it moves in the direction of the radial bearing clearance 49 and is discharged to the outside through the communication hole 67. The lubricant in the inner circumferential groove 97 is replenished into the radial bearing clearance 49, and the lubricant in the outer circumferential groove 69 is replenished into the thrust bearing clearance 53. The shaft member 41
The lubricant splashed radially outward from the thrust bearing clearance 53 during rotation of the housing 31
is prevented from moving radially outward. Note that since the hydrodynamic groove bearing device located above and the hydrodynamic groove bearing device located below are symmetrical, the hydrodynamic groove bearing device located below is similar to the hydrodynamic groove bearing device located above. It has similar effects. In addition, the illustrated spindle has less runout in both the radial direction non-rotation speed synchronous component and the axial direction non-rotation speed synchronous component runout.
There is also no bearing noise.

In the illustrated embodiment, the radial bearing surface 51 is provided with a groove 57 for generating dynamic pressure for the radial bearing.
A groove 5 for generating dynamic pressure for the radial bearing is formed in at least one of the radial bearing surface 37 and the radial bearing surface 51.
7 may be provided.

In addition, the thrust bearing surface 39 and the thrust bearing surface 55
A groove 61 for generating dynamic pressure for a thrust bearing may be provided in at least one of the two.

Furthermore, a communication hole 67 is provided in at least one of the housing 31 and the shaft member 41 through which a boundary 65 between the radial bearing clearance and the thrust bearing clearance communicates with the atmosphere.
may be provided.

In addition, when the dynamic pressure generation groove 57 for the radial bearing is a herringbone groove, the bent portion 59 of this herringbone groove forms the radial bearing clearance 4.
The groove 9 may be located at the axial center of the groove 9 or may be located closer to the inner circumferential groove 97 than the axial center.

Furthermore, a groove 61 for generating dynamic pressure for the thrust bearing
If the groove is a herringbone groove, the bent portion 63 of the herringbone groove may be located at the center of the thrust bearing clearance 53 in the radial direction, or may be located closer to the outer groove 69 than the center in the radial direction. .

Further, the dynamic pressure generating groove 57 for the radial bearing may be a spiral groove, and the dynamic pressure generating groove 61 for the thrust bearing may be a spiral groove.

Furthermore, the hydrodynamic groove bearing device may be used vertically, horizontally, or inverted.

Further, the rotation of the shaft member 41 or the rotation of the housing 31 may be used.

Further, the housing 31 may be constructed from one member by integrating the outer cylinder 33 and the sleeve 35, or the housing 31 may be made of the sleeve 35 alone without using the outer cylinder 33.

Further, the shaft 43 and the upper annular member 45 may be integrated into one member.

According to the hydrodynamic groove bearing device of this invention, a communication hole 67 is provided in at least one of the housing 31 and the shaft member 41 so that the boundary 65 between the radial bearing clearance and the thrust bearing clearance communicates with the atmosphere. There is no negative pressure in the boundary area 65 between the thrust bearing clearance and no air bubbles are generated in the boundary area 65 between the radial bearing clearance and the thrust bearing clearance, so the dynamic torque of the bearing does not fluctuate and radial vibration and axial There is no vibration and there is no lubrication failure even after long periods of rotation.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional hydrodynamic groove bearing device.
Figure 2 is a bottom view of the thrust bearing surface shown in Figure 1, Figure 3 is a chart showing the fluid pressure distribution in the radial bearing clearance shown in Figure 1, and Figure 4 is a diagram showing the pressure distribution of the fluid in the radial bearing clearance shown in Figure 1. A diagram showing the pressure distribution of fluid, FIG. 5 is a sectional view of a spindle using a hydrodynamic groove bearing device showing an embodiment of this invention, and FIG. 6 is a plan view of the thrust bearing surface shown in FIG. 5. 7 is a chart showing the pressure distribution of the fluid in the radial bearing clearance shown in FIG. 5, and FIG. 8 is a chart showing the pressure distribution of the fluid in the thrust bearing clearance shown in FIG. 5. In the figure, 31 is a housing, 37 is a radial bearing surface, 39 is a thrust bearing surface, 41 is a shaft member, 49
is the radial bearing clearance, 51 is the radial bearing surface, 5
3 is the thrust bearing clearance, 55 is the thrust bearing surface,
57, 61 are grooves for generating dynamic pressure, 65 is a boundary part, 6
7 is a communicating hole.

Claims (1)

[Claims for Utility Model Registration] (1) The housing 31 has a radial bearing surface 37 provided on the inner circumferential surface and a thrust bearing surface 39 provided on the side surface adjacent to each other, and a shaft member disposed on the inner circumference of the housing 31. 41 has a radial bearing surface 51 that faces the radial bearing surface 37 with a radial bearing clearance 49 in between, and a thrust bearing surface 55 that faces the thrust bearing surface 39 with a thrust bearing clearance 53 in between. A groove 57 for generating dynamic pressure for the radial bearing is provided on at least one of the radial bearing surface 51, and a groove 61 for generating dynamic pressure for the thrust bearing is provided on at least one of the thrust bearing surface 39 and the thrust bearing surface 55. The hydrodynamic groove bearing device is characterized in that at least one of the housing 31 and the shaft member 41 is provided with a communication hole 67 through which a boundary 65 between the radial bearing clearance and the thrust bearing clearance communicates with the atmosphere. Groove bearing device. (2) The hydrodynamic groove bearing device according to claim 1, wherein the communication hole 67 is provided in the shaft member 41. (3) The hydrodynamic groove bearing device according to claim 1, wherein the communication hole is provided in the housing 31. (4) A utility model registration request in which the dynamic pressure generation groove 57 for a radial bearing is a herringbone groove, and the bent portion 59 of the herringbone groove is located on one side of the axial center of the radial bearing clearance 49. The hydrodynamic groove bearing device according to item 1. (5) A request for registration of a utility model in which the dynamic pressure generating groove 61 for the thrust bearing is a herringbone groove, and the bent portion 63 of the herringbone groove is located on one side of the radial center of the thrust bearing clearance 53. The hydrodynamic groove bearing device according to item 1.