JPS6311384Y2 - - Google Patents

Description

[Detailed Description of the Invention] A. Field of the Invention This invention relates to an improvement of a hydrodynamic radial bearing that is comprised of a pair of mutually opposing and cooperating receiving surfaces, each of which has a groove for generating hydrodynamic pressure.

B. Prior Art As shown in FIG. 1, a hydrodynamic radial bearing is composed of a bearing surface 2 on the rotating shaft 1 side, and a bearing surface 4 on the supporting member 3 side that faces and cooperates with the bearing surface 2.
Either bearing surface (in Figure 1, bearing surface 2 on the rotating shaft side)
A groove 5 for generating dynamic pressure is formed in the groove.

It is known that this type of bearing is used in precision spindle devices in audio equipment, information equipment, and the like. For an example, see Japanese Patent Application Laid-Open No. 57-37116.

Conventionally, the diameter D of the rotating shaft 1 and the bearing width B are set substantially equal to each other. Further, the bearing clearance Δr is constant in the axial direction between the bearing widths B. Therefore, the friction torque of the bearing is large, especially when oil or grease is used as a lubricant. In order to suppress the friction torque of the bearing to less than the drive torque of the motor that drives the rotating shaft 1, the radial rigidity of the bearing must be sacrificed. Calculatedly, it is possible to increase the radial rigidity of the bearing by narrowing the bearing width and reducing the bearing clearance.
In this case, this type of bearing has the fatal disadvantage of poor lubricant retention performance due to the narrow width of the bearing.

C. Purpose of the invention This invention aims to provide a hydrodynamic radial bearing with a structure that can solve the contradictory problems of reducing friction torque and increasing radial rigidity.

D. Structure of the invention In order to achieve the above object, the hydrodynamic radial bearing of this invention consists of a pair of opposing bearing surfaces,
A flange formed on one of the bearing surfaces and protruding in the radial direction with a width smaller than the bearing width to make the bearing gap in the part smaller than in other parts, and one of the flange parts on both sides of the flange in the width direction. It includes an annular groove formed in the surface, and a plurality of approximately "8"-shaped grooves formed in any one of the receiving surfaces within the width of the bearing and on the axially outer side of each of the annular grooves.

E. Effect of the invention In this structure, the flange 22 substantially functions as a radial bearing, and both side portions of the flange function as a so-called pump that actively pushes lubricant into the bearing gap. As the rotating shaft 10 rotates,
Due to the pump action, lubricant is supplied to the bearing gap via the annular groove 13.

F. Effects of the invention According to this invention, contradictory problems such as reducing frictional torque and increasing radial rigidity can be solved at the same time. Furthermore, due to the improved radial rigidity, it can be used in a vertical spindle device to reduce rotational runout. Furthermore, since it has a pump function, lubricant retention performance is improved, ensuring stable bearing performance over a long period of time. The annular groove 13 contributes to improved lubricant retention performance, and also ensures good bearing performance by circulating the lubricant in the circumferential direction of the rotating shaft 10 from the low-pressure part to the high-pressure part of the bearing gap.

G. Embodiments The features of this invention will become clearer from the following description of embodiments shown in the drawings.

Referring to FIG. 2 showing the first embodiment of this invention, the hydrodynamic radial bearing has a bearing surface 1 of a rotating shaft 10.
1, and a receiving surface 2 of the support member 20 that faces and cooperates with this.
1. A substantially eight-shaped groove 12 is formed in the receiving surface 11 on the rotating shaft side. This groove may be formed in the receiving surface 21 on the support member side.

A flange portion 22 is formed on the receiving surface 21 of the support member 20 and has a width b smaller than the bearing width B and projects in the semi-longitudinal direction,
The bearing gap 30 in this portion is made small (Δr<Δr1). On the other hand, in the portions located on both sides of the axial direction of the flange 22, the radial clearance Δr2 is larger than that in the flange 22 (Δr1>Δr2), forming a space 31 that functions as a lubricant retainer.

Thus, the width b portion plays the original function of the radial bearing, and the width B-b portions located on both sides of the collar portion 22 serve as a so-called pump for retaining lubricant.

Note that instead of providing the flange portion 22 on the support member 20 side, a flange portion may be provided on the rotating shaft 10 side.

Annular grooves 13 are provided at positions corresponding to both sides of the collar portion 22 of the support member 20 of the rotating shaft 10. In this case, as the rotating shaft 10 rotates, the lubricant is supplied to the bearing gap 30 via the annular groove 13 by the pump action described above. This annular groove 13 functions as follows. The lubricant pushed into the annular groove 13 by the pump action and the lubricant leaked from the high-pressure part of the bearing gap circulate in the annular groove 13 in the circumferential direction of the rotating shaft 10 and are released from the non-load side of the bearing part. Bearing clearance 3
Encourages entry into 0.

By providing one or more grooves 14 that connect the annular grooves 13 located on both sides of the flange 22 in the axial direction as shown in FIG. 3, lubricant can be retained and smoothly supplied to the bearing gap. be able to.

In this way, the width b serves as a radial bearing.
This part is a perfect circular bearing or a step-shaped bearing, which by itself has poor lubricant retention ability, but as mentioned above, in addition to the action of the pump part, the annular groove 13 and groove 14 The effects work together,
Guarantees lubricant retention and thus good bearing performance.

FIG. 4 shows a slightly modified version of the embodiment shown in FIG. That is, when used in a vertical piston device in which the rotating shaft 10 extends vertically as shown, it is advantageous to provide a collar 23 on the axially outer side of each cavity 31 to prevent lubricant from leaking. The dimensions of this collar 23 are set so that the gap Δr3 has a relationship of Δr1<Δr3<Δr2. This embodiment is extremely advantageous when applied not only to vertical spindle devices, but also to horizontal devices, especially portable devices, due to its sealing function.

FIG. 5 shows an embodiment in which an easily machined screw is used in place of the substantially eight-shaped groove 12 in the embodiments of FIGS. 2 to 4. That is, the rotating shaft 10
The left-hand thread 15 and right-hand thread 16 formed in the groove 12 are caused by rotation of the rotating shaft 10 in the direction of the arrow in the figure.
It has the same effect as

[Brief explanation of drawings]

Figure 1 is a cross-sectional view of a conventional hydrodynamic radial bearing.
2 to 5 are cross-sectional views of dynamic pressure type radial bearings according to embodiments of the present invention. DESCRIPTION OF SYMBOLS 10... Rotating shaft, 11... Receiving surface, 12... Approximately "eight" shaped groove, 13... Annular groove, 14... Groove,
15, 16... screw, 20... support member, 21...
...Bearing surface, 22, 23...Flame, 30...Bearing gap, 31...Vacancy.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a pair of opposing bearing surfaces, which protrude in the radial direction with a width smaller than the bearing width formed on either of the bearing surfaces, so that the bearing gap in that part is narrower than that in other parts. a flange made smaller; an annular groove formed on one of the bearing surfaces on both sides of the axial direction of the flange; A dynamic pressure type radial bearing including a plurality of approximately "8" shaped grooves. (2) The motion according to claim 1 of claim 1, characterized in that one or more grooves are formed on one of the receiving surfaces so that the annular grooves located on both sides in the axial direction of the flange communicate with each other. Pressure type radial bearing. (3) The dynamic pressure type radial bearing according to Claim 1 of the Utility Model Registration Claim, characterized in that the substantially "eight" shaped groove is configured with a left-hand thread and a right-hand thread. (4) A practical use characterized in that cavities that function as lubricant retainers are formed on both sides of the collar in the axial direction, and further collars that protrude in the radial direction are located outside of each cavity in the axial direction. Dynamic pressure type radial bearing according to claim 1 of patent registration claim. (5) The dynamic pressure type according to claim 4 of claim 4, characterized in that the radial clearance in the further flange is larger than that in the first-mentioned flange and smaller than that in the void space. Radial bearing.