JPH049925B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a fluid radial bearing device that uses fluid as a lubricant.

In the fluid radial bearing device, as shown in FIG. 1, a bearing gap 3 formed between a rotating shaft 1 and a radial bearing 2 is filled with a fluid such as lubricating oil.

In such a hydrodynamic radial bearing device, the spacing between the bearing gaps is equal over the entire circumference, and the rotating shaft 1
When the rotation of the rotating shaft 1 starts, the rotating shaft 1 rotates without changing the position of the center Q. However, when the rotation starts with the bearing gaps being unequal all around the circumference, the center Q of the rotating shaft 1 rotates. It rotates while its position changes at a constant cycle, that is, it rotates while making a turning movement.

To explain this using FIG. 2, FIG. 2a shows a state before the rotating shaft 1 starts rotating, and the spacing of the bearing gaps is in a non-uniform state. When the rotating shaft 1 starts rotating in the clockwise direction of the arrow from this state, the fluid filled in the bearing gap 3 also starts to flow clockwise in a laminar flow as the rotating shaft 1 rotates. However, since the average flow velocity V ₂ of the fluid is half the rotational speed V ₁ of the rotating shaft 1, the rotating shaft 1 rotates while making a swirling motion, and this swirling motion is Repeat the same movement in one cycle. In addition,
Figures 2 a to 2h show the state during two rotations of the rotating shaft 1 at each rotation angle π/2, and to make it easier to understand the rotating state, a point on the rotating shaft 1 is indicated by the symbol A. ing.

On the other hand, hydrodynamic radial bearing devices are used, for example, in the rotary bearing of the turntable of a record player, which is an audio device, but in actual use, depending on the manner of use or when a load is applied to the rotating shaft, During startup, it is normal for the bearing gaps to be unevenly spaced.
For this reason, the rotating shaft performs a turning motion during rotation as described above, but this causes deterioration of the reproduction characteristics of audio equipment and the like.

As a measure to prevent this turning movement, it is thought to be effective to first reduce the spacing between the bearing gaps, but it is difficult in terms of processing accuracy to reduce the spacing to the point where the turning movement can be ignored in audio equipment and the like.
Another countermeasure is to consider a configuration in which side pressure P ₁ is applied to the rotating shaft 1 to constantly press the rotating shaft 1 against one side of the inner circumferential surface of the radial bearing so that the rotating shaft 1 does not displace as shown in Figure 3. However, in this case,
During rotation, the resistance force P ₂ due to the hydraulic pressure of the fluid against the lateral pressure P ₁
This has the disadvantage of causing large rotational losses.

The present invention provides a radial bearing device that prevents rotational loss of the rotating shaft by precisely aligning the axis of the rotating shaft with the axial center of the radial bearing, and in this state, rotating the rotating shaft without performing a turning motion. The purpose of this invention is to provide the following information, and will be described below with examples.

In Fig. 4, 1 indicates a rotating shaft, and 2 indicates a radial bearing, and a cross-section of the main part in the X-X direction of the figure corresponds to a cross-sectional view of the main part of the bearing device shown in Fig. 1 or 2, etc. .

The ring member ₄ , in which the through hole 41 is formed to have a diameter larger than the inner diameter of the radial bearing 2, is loosely fitted onto the rotating shaft 1, and as shown in FIG. The inner circumferential surface 2 of the radial bearing 2 protrudes from _{the 1} side so as to cover a part of the bearing gap 3, and is attached to the upper end surface ₂ of the radial bearing 2 with screws 5, 5, thereby engaging the rotating shaft 1 and The outer circumferential surface 1 of the rotating shaft ₁ at a part of the inner circumference of the bearing 2
It serves as a guide means for prohibiting contact between the rotary shaft 1 and the inner circumferential surface 2 ₁ of the radial bearing 2, and for guiding the rotary shaft 1 to a position where its center Q and the center of the radial bearing 2 coincide. Here, the maximum protrusion amount T in the radial direction from the inner circumferential surface ₂₁ side of the radial bearing 2 at the portion where the ring member 4 serving as the guide means covers the bearing gap 3 is uniform over the entire circumference of the bearing gap 3. The ring member 4 is set to be equal to the interval in the state (Fig. 5 d to h), and although the ring member 4 is always engaged with the rotating shaft 1 while the rotating shaft 1 is rotating, the ring member 4 is always engaged with the rotating shaft 1.
Do not apply lateral pressure to the

With this configuration, even if the rotating shaft 1 starts rotating from a state where the spacing between the bearing gaps 3 is uneven as shown in FIG. A position where it engages with the through hole ₄₁ of the ring member 4 protruding from the inner circumferential surface ₂₁ side and the spacing of the bearing gap 3 is uniform, that is, a position where its axis coincides with the axis of the radial bearing 2. After being guided to this position, the rotating shaft 1 rotates without changing the position of its center Q. Note that, similarly to FIG. 2, FIGS. 5a to 5h show states during two rotations of the rotating shaft 1 at each rotation angle π/2.

In the above embodiment, the maximum protrusion amount T of the ring member 4 serving as the guide means from the inner circumferential surface 2 ₁ side of the radial bearing 2 is calculated as I set it equal to the interval, but
The maximum protrusion amount T of the ring member 4 can also be set to a value within a required range that is equal to or less than the spacing in the uniform state. This is because the center Q of the rotating shaft 1 is guided near the center of the radial bearing 2.
The centering force of the radial bearing 2 (fluid) itself on the rotating shaft 1, that is, the position where the center Q of the rotating shaft 1 and the center of the radial bearing 2 coincide (the position where the spacing between the bearings is equal over the entire circumference) This is because a pulling force acts on the Therefore, in this case, the rotating shaft 1
is guided to a position where its center Q and the center of the radial bearing 2 substantially coincide by engaging with the ring member 4 at the initial stage of rotation. Then, as the rotary shaft 1 rotates thereafter, the centering force is applied to the rotary shaft 1 to release the engagement with the ring member 4 and guide the rotary shaft 1 to a position where its center Q coincides with the center of the radial bearing 2.

Therefore, in this case, since the rotating shaft 1 rotates in a state where the engagement with the ring member 4 is released, rotation loss of the rotating shaft 1 due to friction with the ring member 4 can be eliminated.

Further, in the above-described embodiments, the guide means is configured with a ring member, but the guide means is not limited to this, and the same functions and effects can be achieved in various embodiments. Further, the maximum protrusion T of the guide means from the inner peripheral surface of the radial bearing is
It is also possible to arrange the bearings so that they can be adjusted within a required range that is less than or equal to the spacing between the bearings 3 when the spacing is uniform over the entire circumference. Further, in the above-described embodiment, the guide means was provided on the end face of the bearing, but it may be provided inside the bearing.

According to the above fluid radial bearing device of the present invention,
Since the rotating shaft rotates without performing a turning motion with its axis aligned with the axis of the radial bearing, rotation loss of the rotating shaft can be prevented.

[Brief explanation of drawings]

1 to 3 are sectional views of main parts of a hydrodynamic radial bearing device for explaining a conventional example, FIG. 4 is a perspective view of main parts of an embodiment of the device of the present invention, and FIGS. 5 a to h
4A and 4B are cross-sectional views of essential parts showing the operation of the embodiment shown in FIG. 4, respectively. 1... Rotating shaft, 1 ₁ ... Outer peripheral surface of rotating shaft, 2...
...Radial bearing, 2 ₁ ...Inner peripheral surface of radial bearing,
3...Bearing gap, 4...Ring member.

Claims (1)

[Scope of Claims] 1. A fluid radial bearing device that rotatably supports a rotating shaft, and a fluid radial bearing formed by filling a fluid between the bearing formed by the inner circumferential surface of the bearing and the outer circumferential surface of the rotating shaft. a bearing, which protrudes from the inner circumferential surface of the hydrodynamic radial bearing to cover a portion between the bearings and engages with the rotating shaft, and which extends along the radial direction of the hydrodynamic radial bearing. The maximum amount of protrusion from the circumferential surface is
and a guide means whose spacing is equal to or less than the spacing when the spacing between the bearings is uniform over the entire circumference, and the rotary shaft is engaged with the guide means at least in the initial stage of its rotation. A fluid radial bearing device characterized in that the center is guided to a position that substantially coincides with the center of the fluid radial bearing.