JPS633462Y2 - - Google Patents

Description

[Detailed description of the invention] A. Technical field This invention consists of a bearing surface on the rotating shaft side and a bearing surface on the supporting member side opposing this, and either bearing surface has a groove for generating dynamic pressure. The present invention relates to a hydrodynamic radial bearing.

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 support member 3 side that faces and cooperates with the bearing surface 2. A groove 5, for example, in a herringbone shape as shown, for generating dynamic pressure is formed on the receiving surface (in the illustrated example, the receiving surface 2 on the rotating shaft side). A lubricant is supplied to the bearing gap 6 between these bearing surfaces. As the rotating shaft 1 rotates in the direction of the arrow in the figure, pressure is generated within the bearing clearance, and the bearing functions as a radial bearing.

This type of bearing has recently come to be used in spindle devices for audio, optical, and information-related equipment because it is superior in terms of load capacity, torque unevenness, noise, and life when oil or grease is used as a lubricant. Ta.

However, in the case of the conventional structure shown in Fig. 1, observation experiments of the behavior of lubricant in the bearing clearance show that not only when there is insufficient lubricant in the bearing clearance before operation, but also when there is insufficient lubricant in the bearing clearance before operation. Even if sufficient lubricant is filled in the bearing clearance and at both ends of the bearing before operation, air bubbles may enter the bearing clearance.
Bubble growth or irregular entry and exit of air bubbles into and out of the bearing is observed.

Under such conditions, vibrations in the bearing, a decrease in load capacity, torque fluctuations, etc. occur, and the functionality of the spindle device is significantly impaired.

C. Purpose of the invention This invention aims to provide a hydrodynamic radial bearing having a structure that can prevent air bubbles from entering the bearing gap and solve the above-mentioned conventional problems.

D. Structure of the invention In order to achieve the above object, this invention is composed of a bearing surface 12 on the rotating shaft 11 side and a bearing surface 14 on the supporting member 13 side opposite thereto, and there is no movement on either of the bearing surfaces. Means 17, 18, 1 for feeding lubricant into the bearing clearance 16, which is provided with a pressure generating groove 15 and located on both axially outer sides of the bearing part.
7', 18', 17'', 18'', and a cavity 19 adjacent to each of the means in the axial direction and partially overlapping with the dynamic pressure generating groove 15 in the axial direction; It is characterized by comprising one or more air vent holes 20 that connect each cavity 19 with the outside of the bearing.

E. Effect of the invention The means 17, 18, 17', 18', 17'', 18'' for feeding lubricant into the bearing clearance 16 are as follows:
The lubricant is first fed into the cavity 19 by the pumping action, and the required amount is supplied to the bearing clearance 16 from a lubricant reservoir formed within the cavity 19. Even if air bubbles are present in the lubricant, they are discharged from the cavity 19 through the air vent hole 20 to the outside of the bearing, and are prevented from entering the bearing clearance 16. The lubricant reservoir formed in the cavity 19 also serves to prevent dust from entering the bearing clearance 16.

F. Effects of the invention According to this invention, since air bubbles are prevented from entering and exiting the bearing clearance, there is no fluctuation in the operating torque of the bearing, and therefore there is no uneven rotation. . Furthermore, since the bearing clearance is always filled with lubricant, the bearing load capacity does not fluctuate or decrease. Furthermore, since dust is prevented from entering the bearing clearance, there is no damage to the bearing. In this way, it is possible to provide a dynamic pressure type radial bearing that can guarantee stable performance over a long period of time.

Examples Examples of this invention shown in FIGS. 2 to 6 will be described below. Note that the same reference numerals refer to the same parts or parts throughout all the figures.

First, in Figure 2, the dynamic pressure type radial bearing is
It is composed of a receiving surface 12 on the rotating shaft 11 side and a receiving surface 14 on the supporting member 13 side that faces and cooperates with the receiving surface 12. The receiving surface 12 on the rotating shaft side has a groove 15 for generating dynamic pressure.
has been formed. This groove for generating dynamic pressure may be formed on the receiving surface 14 on the supporting member side, and is not limited to the herringbone shape as shown in the drawings, but other patterns may also be adopted.

A right-handed thread 17 and a left-handed thread 18 are formed on the rotating shaft 11 on both axial sides of the receiving surface 12 provided with the groove 15 . Each thread and bearing surface 12 are axially separated by a portion of smaller diameter than both, providing a cavity 19 that functions as a lubricant reservoir. The cavity 19 communicates with the bearing clearance 16 and partially overlaps with the groove 15 in the axial direction.

Right-hand threads and left-hand threads are indicated by reference numeral 1 in Figure 3, respectively.
They can also be formed on the support member 13 side, as shown at 7' and 18'.

These screws act as a so-called pump that feeds lubricant near the axially outer side of the gap with the support member 13 and inside toward the bearing gap 16 as the rotating shaft 11 rotates in the direction of the arrow in the figure. act. In addition, although the space 19 is filled with lubricant from the beginning, this lubricant is forced into the space 19 even more forcefully by the pump action described above, forming a lubricant reservoir in the area. do. As mentioned above, since the cavity 19 communicates with the bearing gap 16, the required amount of lubricant is supplied to the bearing gap 16 from the lubricant reservoir.

Note that the lubricant reservoir formed in the cavity 19 is caused by the presence of dust in the bearing clearance 16 when the lubricant fed by the pump action contains dust.
It also acts to prevent it from entering the body.

Reference numeral 20 denotes an air vent hole that connects the cavity 19 with the axially outer side of the bearing portion. Due to the presence of the air vent hole 20, compressed air bubbles mixed in the lubricant sent into the cavity 19 by the pumping action are released to the outside of the bearing, thereby more completely preventing air bubbles from entering the bearing clearance 16. can do. The air vent hole 19 may be made to communicate with the gap between the rotary shaft 11 and the support member 13 in the part that performs the pumping action (see FIG. 6).

In another embodiment shown in FIG.
In place of the screw in the embodiment of FIG.
In this case, due to centrifugal force, the lubricant adhering to the tapered portions 17'' and 18'' is sent toward the larger light diameter, that is, the cavity 19.

Referring to FIG. 5, which shows another embodiment, an annular groove 22 communicating through a communication hole 21 opens into the bearing gap 16 on both sides of the bearing width center in the axial direction and within the bearing width. The annular groove 22 and the communication hole 21 may be provided on the support member 13 side as shown in the figure, or may be provided on the rotating shaft 11 side. Both are independent of each other, for example, the annular groove 22 is connected to the support member 1.
Third, the communication holes 21 can be provided in each of the rotating shafts 11.

The communication hole 21 serves to balance the pressure on both sides of the bearing clearance 16 in the axial direction. That is,
If the pressure in the bearing clearance 16 differs in the axial direction,
By balancing this, malfunctions such as uneven distribution of the lubricant and even outflow of the lubricant due to the flow of the lubricant in the bearing gap 16 toward the low pressure side and the accompanying intrusion of air bubbles into the bearing gap 16 are prevented. Similarly, if the pressure within the bearing clearance 16 differs in the axial direction, the lubricant would flow out to the low pressure side if the communication hole 21 were not provided, but in this embodiment, the lubricant has a balanced pressure. Communication hole 2 until
It only moves to the low pressure side through 1 and does not flow out to the outside.

As another means for achieving pressure balance, as shown in FIG. 6, for example, a plurality of communication holes 23 may be provided on the rotating shaft 11 side to connect both sides of the bearing clearance 16 in the axial direction.

[Brief explanation of the drawing]

Figure 1 is a cross-sectional view of a conventional hydrodynamic radial bearing.
2 to 6 are sectional views of dynamic pressure type radial bearings that are embodiments of this invention. 11... Rotating shaft, 12, 14... Reception surface, 13...
...Support member, 15...Groove for dynamic pressure generation, 16...Bearing clearance, 17, 18, 17', 18'...Screw,
17″, 18″…Tapered part, 19…Vacancy, 2
0...Air vent hole.

Claims (1)

[Claims for Utility Model Registration] (1) Consisting of a bearing surface on the rotating shaft side and a bearing surface on the opposing support member side, one of the bearing surfaces is provided with a groove for generating dynamic pressure. A means for feeding lubricant into bearing gaps located on both axially outer sides of the bearing portion in a hydrodynamic radial bearing;
A cavity adjacent to the means on the inside in the axial direction of each of the means and partially overlapping with the groove for generating dynamic pressure in the axial direction, and one or more air vent holes communicating each of the cavities with the outside of the bearing. Equipped with dynamic pressure type radial bearing. (2) The hydrodynamic radial bearing according to claim 1, wherein the means is a screw formed on either the rotating shaft or the support member. (3) The hydrodynamic radial bearing according to claim 1, wherein the means is a tapered portion formed on the rotating shaft. (4) The dynamic pressure system according to any one of claims 1 to 3 of claims 1 to 3, wherein the air vent hole communicates the void space with a gap between the rotating shaft and the support member in the means portion. type radial bearing. (5) The dynamic pressure type radial bearing according to claim 1 of claim 1, which is characterized by comprising one or more means for making both sides of the bearing clearance communicate with each other in the axial direction. (6) The means for connecting both sides of the bearing clearance in the axial direction communicates with each other an annular groove formed on either the rotating shaft or the support member on both axially outer sides and within the width of the bearing. The hydrodynamic radial bearing according to Claim 5 of the Utility Model Registration Claim, characterized in that it includes a communication hole formed in either one of the rotating shaft and the supporting member.