JP2583786Y2 - Dynamic pressure bearing device - Google Patents

Description

[Detailed description of the invention]

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an inexpensive hydrodynamic bearing device whose structure can be simplified.

[0002]

2. Description of the Related Art Conventionally, as a dynamic bearing device of this kind,
There is one shown in FIG. This dynamic pressure bearing device is a cylindrical member 2
1 and a shaft member 22 to be inserted into the cylindrical member 21, and two dynamic pressure grooves 23 and 25 having different groove patterns in the axial direction and having different groove patterns are provided on the outer peripheral surface of the shaft member 22. . That is, the axial length a of the dynamic pressure groove 23 is longer than the axial length b of the dynamic pressure groove 25.
The bearing gap t between the dynamic pressure groove 23 and the dynamic pressure bearing portion 26 including the inner peripheral surface of the cylindrical member 21, and the dynamic pressure bearing portion 27 including the dynamic pressure groove 25 and the internal peripheral surface of the cylindrical member 21. The bearing gap t is set to the same value. Therefore, the load capacity of the dynamic pressure bearing 26 is larger than the load capacity of the dynamic pressure bearing 27.

As described above, in the above-mentioned hydrodynamic bearing device, the load capacities of the two hydrodynamic bearing portions 26 and 27 are made different in consideration of the balance of the load applied to the bearing device.

[0004]

However, in the above-mentioned conventional hydrodynamic bearing device, the axial length a of the hydrodynamic bearing portion 26 and the axial length b of the hydrodynamic bearing portion 27 are made different from each other. Since the load capacity of the dynamic pressure bearing portion 26 and the load capacity of the dynamic pressure bearing portion 27 are different, the groove pattern of the dynamic pressure groove 23 of the dynamic pressure bearing portion 26 and the dynamic pressure groove 25 of the dynamic pressure bearing portion 27 are different. Since the groove pattern is different from the above, there is a disadvantage that the structure becomes complicated.

Since the axial length a of the dynamic pressure groove 23 is different from the axial length b of the dynamic pressure groove 25, the concave portion 21a for retaining lubricant provided on the inner peripheral side of the cylindrical member 21 is Since the cylindrical member 21 cannot be provided at the center of the member 21 and the shape of the cylindrical member 21 is asymmetric in the axial direction, the cylindrical member 21
Attention must be paid to the direction of assembling, and the man-hour for assembling becomes complicated, resulting in an increase in cost.

Further, when the cylindrical member 21 is mounted on a housing (not shown) when the cylindrical member 21 is press-fitted into the housing, the bearing clearance of the dynamic pressure bearing portion inside the cylindrical member 21 at the press-fitted portion is further increased. There is a case where t changes and the balance of the bearing load capacity changes. For this reason, when mounting the cylindrical member 21 to the housing, there is also a disadvantage that it is necessary to perform a troublesome operation of fixing the cylindrical member 21 with an adhesive without pressing the cylindrical member 21 into the housing.

It is an object of the present invention to provide a dynamic pressure bearing device which has a simple structure and is easy to assemble and which can adjust the balance of the bearing load capacity.

[0008]

In order to achieve the above object, a hydrodynamic bearing device according to the present invention includes a cylindrical member and a shaft member inserted into the cylindrical member, and has an inner peripheral surface or a cylindrical member. At least one of the outer peripheral surfaces of the shaft member is provided with two axially separated dynamic pressure grooves having the same groove pattern, and the dynamic pressure bearing includes one of the two dynamic pressure grooves. The outer peripheral surface of the cylindrical member on the outer peripheral side of the dynamic pressure bearing portion is press-fitted into the housing so that the bearing clearance of the portion is reduced to a predetermined bearing clearance.

[0009]

According to the above construction, the two dynamic pressure grooves have the same groove pattern, and the bearing gap of the dynamic pressure bearing portion including one of the dynamic pressure grooves is narrowed to a predetermined bearing gap. The outer peripheral surface of the cylindrical member on the outer peripheral side of the dynamic pressure bearing portion is press-fitted into the housing.

In other words, in the hydrodynamic bearing device of the present invention, the bearing clearance of one of the hydrodynamic bearing portions whose load capacity is to be increased is
So that it is smaller than the bearing clearance of the other dynamic pressure bearing
The outer peripheral surface of the cylindrical member on the outer peripheral side of the one dynamic pressure bearing portion is pressed into the housing so that the load capacity of the one dynamic pressure bearing portion is larger than the load capacity of the other dynamic pressure bearing portion. ing. Therefore, according to the present invention, the bearing load capacities of the two dynamic pressure bearing portions can be different without changing the groove patterns of the dynamic pressure grooves of the two dynamic pressure bearing portions. Therefore, according to the present invention, a dynamic pressure bearing device that has a simple structure and is easy to assemble and that can adjust the balance of the bearing load capacity is realized.

[0011]

BRIEF DESCRIPTION OF THE DRAWINGS FIG. FIG. 1 shows an embodiment of the hydrodynamic bearing device of the present invention. As shown in FIG. 1, the hydrodynamic bearing device of this embodiment
It has a cylindrical member 1 and a shaft member 2 inserted into the cylindrical member 1. On the outer peripheral surface of the shaft member 2, two axially separated dynamic pressure grooves 3 and 5 having the same groove pattern are provided.

The bearing gap of the dynamic pressure bearing portion 6 defined by the dynamic pressure groove 3 and the inner peripheral surface of the cylindrical member 1 and the dynamic pressure defined by the dynamic pressure groove 5 and the inner peripheral surface of the cylindrical member 1 Before the cylindrical member 1 is press-fitted into the housing 7, both of the bearing gaps of the bearing portion 8 have the same dimensions.

The outer peripheral surface of the cylindrical member 1 on the outer peripheral side of the dynamic pressure bearing portion 6 including the dynamic pressure groove 3 is press-fitted into the housing 7. At the time of press-fitting, the interference at the time of press-fitting is set so that the bearing gap of the dynamic pressure bearing portion 6 is reduced to a predetermined bearing gap c. In other words, the bearing gaps c and d of the dynamic pressure bearings 6 and 8 are set such that the dynamic load bearing 6 has a larger bearing load capacity than the dynamic pressure bearing 8.
Is set.

The non-dynamic pressure groove forming portion 10 of the shaft member 6
A concave portion 1a for retaining lubricant is provided on the inner peripheral surface of the cylindrical member 1 opposed to. The concave portion 1a is formed substantially at the center of the cylindrical member 1 in the axial direction.

According to the above-structured hydrodynamic bearing device,
The three dynamic pressure grooves 3 and 5 have the same groove pattern, and the dynamic pressure bearing portion 6 includes one dynamic pressure groove 3 so that the bearing gap of the dynamic pressure bearing portion 6 is reduced to a predetermined bearing clearance c. The outer peripheral surface of the outer cylindrical member 1 is pressed into the housing 7.

That is, in the hydrodynamic bearing device of the above embodiment, the bearing gap c of the hydrodynamic bearing portion 6 for which the bearing load capacity is to be increased is smaller than the bearing gap d of the other hydrodynamic bearing portion 8. As described above, the outer peripheral surface of the cylindrical member 1 on the outer peripheral side of the dynamic pressure bearing portion 6 is pressed into the housing 7 so that the load capacity of the dynamic pressure bearing portion 6 is larger than the load capacity of the dynamic pressure bearing portion 8. I have. Therefore, according to the above embodiment, the groove patterns of the dynamic pressure grooves 3, 5 of the two dynamic pressure bearing portions 6, 8 are made different in order to make the bearing load capacities of the two dynamic pressure bearing portions 6, 8 different. No need.

Therefore, the shape of the shaft member 2 can be made symmetrical in the axial direction, and the shape of the cylindrical member 1 can be made symmetrical in the axial direction, so that the structure can be simplified. You do not need to pay attention to the direction of
The number of assembling steps is reduced, and costs can be reduced. Further, according to the embodiment, since the cylindrical member 1 is press-fitted into the housing 7 and fixed, the fixing to the housing can be simplified as compared with a conventional example in which the cylindrical member is fixed to the housing with an adhesive.

That is, according to the above embodiment, an inexpensive hydrodynamic bearing device which has a simple structure, is easy to assemble, and can adjust the balance of the axial load capacity of the bearing can be realized.

In the above embodiment, the dynamic pressure grooves 3 and 5 are provided on the outer peripheral surface of the shaft member 2. However, the dynamic pressure grooves may be provided on the inner peripheral surface of the cylindrical member 1, and the outer peripheral surface of the shaft member may be provided. The dynamic pressure grooves may be provided on both the inner peripheral surface of the cylindrical member.

[0020]

As is apparent from the above description, in the hydrodynamic bearing device of the present invention, the two hydrodynamic grooves have the same groove pattern, and the bearing clearance of the hydrodynamic bearing portion including one of the hydrodynamic grooves is provided. The outer peripheral surface of the cylindrical member on the outer peripheral side of the dynamic pressure bearing portion is press-fitted into the housing so that is reduced to a predetermined bearing clearance.

That is, in the hydrodynamic bearing device of the present invention, the bearing clearance of one of the hydrodynamic bearing portions whose load capacity is to be increased is
So that it is smaller than the bearing clearance of the other dynamic pressure bearing
The outer peripheral surface of the cylindrical member on the outer peripheral side of the one dynamic pressure bearing portion is pressed into the housing so that the load capacity of the one dynamic pressure bearing portion is larger than the load capacity of the other dynamic pressure bearing portion. ing. Therefore, according to the present invention, the bearing load capacities of the two dynamic pressure bearing portions can be different without changing the groove patterns of the dynamic pressure grooves of the two dynamic pressure bearing portions. Therefore, according to the present invention, it is possible to realize a dynamic pressure bearing device that can adjust the balance of the bearing load capacity with a simple structure and a simple assembly.

[Brief description of the drawings]

FIG. 1 is a sectional view of an embodiment of the hydrodynamic bearing device of the present invention.

FIG. 2 is a sectional view of a conventional hydrodynamic bearing device.

[Explanation of symbols]

DESCRIPTION OF SYMBOLS 1 ... Cylinder member, 1a ... Concave part, 2 ... Shaft member, 3,5 ... Dynamic pressure groove, 6,8 ... Dynamic pressure bearing part, 7 ... Housing.

Claims (1)

(57) [Scope of request for utility model registration] A shaft member inserted into the cylindrical member, wherein at least one of an inner peripheral surface of the cylindrical member or an outer peripheral surface of the shaft member has the same groove pattern in an axial direction. Two separate dynamic pressure grooves are provided. Of the two dynamic pressure grooves, the dynamic pressure bearing portion of the dynamic pressure bearing portion includes one of the dynamic pressure grooves so that a bearing gap of the dynamic pressure bearing portion is reduced to a predetermined bearing clearance. A hydrodynamic bearing device wherein an outer peripheral surface of an outer peripheral side cylindrical member is press-fitted into a housing.