JPS6229647B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a spindle unit used in various fields such as office machines, video equipment, and audio equipment.

[Conventional technology]

In a conventional spindle unit, the radial load of the shaft is supported by a pair of radial sliding bearings, and the thrust load of the shaft is supported by a thrust sliding bearing, and the bearing clearance of this thrust sliding bearing and the bearing clearance of the pair of radial sliding bearings are The same lubricant was present in each.

[Problem that the invention seeks to solve]

Therefore, when the viscosity of the lubricant is high, both the radial load capacity and the thrust load capacity are large, but the torque of the radial plain bearing and the thrust plain bearing is high, and when the viscosity of the lubricant is low, the radial and thrust plain bearings have a high torque. Although the torque was low, the load capacity of both the radial sliding bearing and the thrust sliding bearing was small.

The object of this invention is to provide a spindle unit with large thrust load capacity and low torque.

[Means for solving problems]

The shaft body 1 disposed in the cylindrical hole 12 provided in the outer cylinder 11 has cylindrical radial outer surfaces 2 and 3 provided on the outer peripheral surface.
, a planar thrust end surface 6 provided at the shaft end, and a cylindrical seal outer surface 8 provided between the radial outer surfaces 2 and 3 and the thrust end surface 6;
is the radial inner surface 1 which cooperates with the radial outer surfaces 2 and 3.
5, 16, a thrust bottom surface 18 that cooperates with the thrust end surface 6, and a seal inner surface 22 that cooperates with the seal outer surface 8. Groove 7
a groove 9 for performing a sealing action is provided on at least one of the seal outer surface 8 and the seal inner surface 22, and a lubricant is present in the thrust bearing clearance 23 between the thrust end surface 6 and the thrust bottom surface 18;
Radial bearing clearances 27, 2 between the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16 that cooperate with each other
8 is a spindle unit in which at least one of gas and a lubricant having a lower viscosity than the lubricant present in the thrust bearing clearance 23 is present.

[Effect]

During operation of the spindle unit in which the shaft body 1 rotates with respect to the outer cylinder 11, the lubricant around the thrust bearing clearance 23 flows into the thrust bearing clearance 23 by the pumping action of the groove 7 for generating dynamic pressure, and the thrust bearing Section 17 has a large thrust load capacity. In addition, the fluid in the seal gap 19 between the seal outer surface 8 and the seal inner surface 22 flows out toward the thrust bearing gap 23 by the pumping action of the groove 9 that performs the sealing action, so that the lubricant in the thrust bearing gap 23 is the radial bearing clearance 2 between the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16
It will not flow towards 7 and 28. Furthermore, the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16 cooperate with each other.
The radial bearings 13 and 14 have a radial load capacity.

〔Example〕

Next, embodiments of the present invention will be described based on the drawings. In FIG. 1, cylindrical radial outer surfaces 2 and 3 are provided at two locations spaced apart in the axial direction on the outer peripheral surface of a vertically disposed shaft body 1, and these radial outer surfaces 2 and 3 have Herringbone-shaped grooves 4 and 5 for generating dynamic pressure are provided, respectively. A flat thrust end face 6 is provided on one end face of the shaft body 1, and a spiral groove 7 for generating dynamic pressure is provided in the thrust end face 6 as shown in FIG. The shaft body 1 is provided with a cylindrical thrust outer surface 8 between the radial outer surface 3 on the thrust end surface side and the thrust end surface 6, and this seal outer surface 8 has a groove 9 that performs a spiral sealing action.
is provided. The shaft body 1 is disposed in a cylindrical hole 12 provided in an outer cylinder 11, and this outer cylinder 11 has a radial load support member 111, a bottom plate 211 fixed to the thrust load support member 111, and an O-ring 31.
The thrust load support member 411 is fitted into the radial load support member 111 via the thrust load support member 411 and is disposed on the bottom plate 211. The outer cylinder 11 is provided with two cylindrical radial inner surfaces 15 and 16 spaced apart in the axial direction, which cooperate with the radial outer surfaces 2 and 3 to form radial bearing parts 13 and 14. 11 is provided with a planar thrust bottom surface 18 which cooperates with the thrust end surface 6 to constitute the thrust bearing part 17, and a cylindrical seal inner surface 22 which cooperates with the seal outer surface 8 to constitute the seal part 21. ing. The thrust bearing clearance 23 between the thrust end face 6 and the thrust bottom face 18 is
lubricant is present.

When the shaft body 1 rotates with respect to the outer cylinder 11 with the above configuration, the lubricant around the thrust bearing clearance 23 flows into the thrust bearing clearance 23 by the pumping action of the groove 7 for generating dynamic pressure. The thrust bearing portion 17 has a large thrust load capacity.
Further, the fluid in the seal gap 19 between the seal outer surface 8 and the seal inner surface 22 flows out toward the thrust bearing gap 23 due to the pumping action of the groove 9 that performs the sealing action, and the lubricant in the thrust bearing gap 23 flows out. are the radial outer surfaces 2 and 3 and the radial inner surface 1
Radial bearing clearance between 5 and 16 27 and 28
The outflow towards the area has been suppressed. Further, the gas on both sides of the radial bearing clearance 27 on the opening side flows into the radial bearing clearance 27 on the opening side by the pumping action of the dynamic pressure generation groove 4 on the opening side, and also on both sides of the radial bearing clearance 28 on the opposite side. The gas flows into the radial bearing clearance 28 on the opposite opening side by the pumping action of the dynamic pressure generation groove 5 on the opposite opening side, and the pair of radial bearings 13 and 14 have a radial load capacity and low torque. .

3 and 4 show other embodiments of the present invention, in which a sphere 31 is embedded in the center of the thrust bottom surface 18 in the radial direction, so that the flat thrust bottom surface 18 and the thrust end surface 6 are axially connected. Body 1 and outer cylinder 1
Point contact occurs when stationary in step 1. In this way, the torque when starting and stopping the spindle unit is low. In addition, a pair of radial bearing clearances 27,
A lubricant having a lower viscosity than the lubricant present in the thrust bearing clearance 23 is present in each of the thrust bearing gaps 28 . In this way, the radial bearing portions 13, 1
4 has a radial load capacity and low torque, and the thrust bearing portion 17 has a large thrust load capacity. Furthermore, the groove 9 that performs the sealing action has a spiral groove 109 that acts to cause the fluid in the seal gap 19 to flow out toward the thrust bearing gap 23, and the fluid in the seal gap 19 to flow toward the radial bearing gaps 27 and 28. It is composed of a spiral groove 209 that has a draining effect. In this way, the lubricant present in the radial bearing gaps 27 and 28 and the lubricant present in the thrust bearing gap 23 do not mix, so the radial load capacity and torque of the radial bearings 13 and 14 fluctuate, and the thrust bearing Fluctuations in the thrust load capacity and torque of the shaft body 17 and fluctuations in the amount of displacement of the shaft body 1 with respect to the outer cylinder 11 are both small.

In the illustrated embodiment, the grooves 4 and 5 for generating dynamic pressure are provided on the radial outer surfaces 2 and 3, but the radial outer surfaces 2 and 3 and the radial inner surface 15, which cooperate with each other to constitute the radial bearing parts 13 and 14, Dynamic pressure generating grooves 4 and 5 may be provided in at least one of the grooves 16 and 16.

Further, both of the pair of radial bearings 13 and 14 may be sliding contact sliding bearings, or one of the pair of radial bearings 13 and 14 may be a hydrodynamic bearing and the other one may be a sliding bearing. It may also be used as a contact sliding bearing.

Furthermore, a groove 7 for generating dynamic pressure may be provided in at least one of the thrust end face 6 and the thrust bottom face 18.

Furthermore, a groove 9 may be provided on at least one of the seal outer surface 8 and the seal inner surface 22 to perform a sealing action.

〔Effect of the invention〕

According to the spindle unit of the present invention, the shaft body 1 has a flat thrust end surface 6, the outer cylinder 11 has a thrust bottom surface 18 that cooperates with the thrust end surface 6, and the thrust end surface 6 and the thrust bottom surface 18 are connected to each other. At least one side is provided with a groove 7 for generating dynamic pressure, and since lubricant is present in the thrust bearing clearance 23, it has a large thrust load capacity. Further, the shaft body 1 has a cylindrical seal outer surface 8, and the outer cylinder 11 has a seal inner surface 22 that cooperates with the seal outer surface 8,
Since a groove 9 for performing a sealing action is provided on at least one of the seal outer surface 8 and the seal inner surface 22,
The lubricant present in the thrust bearing clearance 23 does not flow into the radial bearing clearances 27 and 28. Furthermore, since the seal outer surface 8 and the seal inner surface 22 are not in contact with each other during operation of the spindle unit when the shaft body 1 rotates with respect to the outer cylinder 11, the torque is low. Further, since the shaft body 1 has cylindrical radial outer surfaces 2 and 3, and the outer cylinder 11 has radial inner surfaces 15 and 16 that cooperate with the radial outer surfaces 2 and 3, lubricant is applied to the radial bearing gaps 27 and 28. The radial bearing portions 13 and 14 have a radial load capacity and a low torque. It can be done. Therefore, the spindle unit can have a low torque as a whole. moreover,
Even if a lubricant different from the lubricant present in the thrust bearing gap 23 exists in the radial bearing gaps 27 and 28, the lubricant present in the radial bearing gaps 27 and 28 and the thrust bearing are separated by the groove 9 that performs a sealing action. Mixing with the lubricant existing in the gap 23 can be prevented, and fluctuations in the load capacity and torque of the radial bearing parts 13 and 14, fluctuations in the load capacity and torque of the thrust bearing part 17, and displacement of the shaft body 1 with respect to the outer cylinder 11 can be prevented. This has the effect that fluctuations in amount can be reduced.

[Brief explanation of the drawing]

FIG. 1 is a sectional view of a spindle unit showing one embodiment of the invention, FIG. 2 is a bottom view of the shaft shown in FIG. 1, and FIG. 3 is a sectional view of a spindle unit showing another embodiment of the invention. 4 are bottom views of the shaft shown in FIG. 3. In the figure, 1 is a shaft body, 2 and 3 are radial outer surfaces, 6 is a thrust end surface, 7 is a groove for generating dynamic pressure, 8 is a seal outer surface, 9 is a groove for sealing, 11 is an outer cylinder, and 12 is a cylinder. shaped holes, 15 and 16 are radial inner surfaces, 18 is a thrust bottom surface, 22 is a seal inner surface, 2
3 is the thrust bearing clearance.

Claims (1)

[Claims] 1. The shaft body 1 disposed in the cylindrical hole 12 provided in the outer cylinder 11 has a cylindrical radial outer surface 2 provided on the outer peripheral surface,
3, a flat thrust end face 6 provided at the shaft end,
The outer tube 1 has a cylindrical seal outer surface 8 provided between the radial outer surfaces 2 and 3 and the thrust end surface 6.
1 has radial inner surfaces 15 and 16 that cooperate with the radial outer surfaces 2 and 3, a thrust bottom surface 18 that cooperates with the thrust end surface 6, and a seal inner surface 22 that cooperates with the seal outer surface 8, and has a seal inner surface 22 that cooperates with the thrust end surface 6. A groove 7 for generating dynamic pressure is provided on at least one side of the thrust bottom surface 18, a groove 9 for performing a sealing action is provided on at least one of the seal outer surface 8 and the seal inner surface 22, and a groove 9 is provided on at least one of the seal outer surface 8 and the seal inner surface 22, and A lubricant is present in the thrust bearing clearance 23 between the radial bearing clearance 2 between the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16 that cooperate with each other.
7 and 28 are spindle units in which at least one of gas and a lubricant having a lower viscosity than the lubricant present in the thrust bearing clearance 23 is present. 2. The spindle unit according to claim 1, wherein grooves 4, 5 for generating dynamic pressure are provided in at least one of the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16, which cooperate with each other. 3. The spindle unit according to claim 1, wherein the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16, which cooperate with each other, constitute a sliding bearing in sliding contact. 4. The spindle unit according to claim 1, wherein the thrust end face 6 and the thrust bottom face 18 are in point contact when the spindle unit is at rest. 5. The spindle unit according to claim 1, wherein the groove 9 that performs the sealing function functions to cause the fluid in the seal gap 19 between the seal outer surface 8 and the seal inner surface 22 to flow out toward the thrust bearing gap 23. 6 Radial bearing clearance 2 between the radial outer surfaces 2, 3 and the radial inner surfaces 15, 16 that cooperate with each other
A lubricant having a lower viscosity than the lubricant present in the thrust bearing clearance 23 is present in the grooves 7 and 28, and the groove 9 that performs a sealing action functions to cause the fluid in the sealing clearance 19 to flow out toward the thrust bearing clearance 23. 2. The spindle unit according to claim 1, comprising a groove 109 and a groove 209 which serves to cause the fluid in the seal gap 19 to flow out toward the radial bearing gaps 27, 28.