JPH0464714A - Sliding bearing for high speed rotation - Google Patents

Abstract

PURPOSE:To prevent self-excited vibration of a rotor, and intake the sufficient air at an oil leading channel part by communicating a circumferential oil channel, at least, of a negative oil film pressure distributed area of a pressure receiving surface with an oil reservoir near the divided joint surfaces in an upper half and an lower half. CONSTITUTION:A through hole 5 is drilled downward in an oil reservoir 6, which is formed in a divided surface of a lower half part 1 of a bearing, to be worked as an oil supply hole and an oil exhaust hole. A wedge type oil leading channel 4 is provided in each divided surface side of a slide surface 3, and while an oil channel 2 is provided in the slide surface 3. Since the oil reservoir 6 is communicated with the oil channel 2 at the end thereof, flow-in of the oil from the oil channel 2 to the oil leading channel 4 is eliminated in a negative oil film pressure distributed area, and the air can be intaken from the axial end sufficiently. Consequently, high stability can be maintained.

Description

DETAILED DESCRIPTION OF THE INVENTION [Object of the Invention] (Industrial Application Field) The present invention relates to a high-speed rotation plain bearing that supports high-speed rotation bodies such as turbines, blowers, and the like.

(Prior art) Bearings with oil grooves, which have pressure relief grooves in the circumferential direction on the lower pressure receiving surface, are commonly used especially in large rotating machines because they improve stability against self-excited vibrations such as oil whip. is used. Its structure is shown in FIG. 3, and its cross-sectional view is shown in FIG. 4.

Generally, near the joint surface where the upper and lower halves of the bearing are divided, there is an oil reservoir for oil supply and oil drainage, and an oil guide groove for smoothing the flow of lubricating oil) at an angle of about 20 to 30 degrees from the joint surface. α in Figure 4) is provided.

The aforementioned oil groove (■) is provided circumferentially along the sliding surface (■) near the axial center of the edge surface (3) of the lower half of the bearing (■), but the end position of this oil groove (■) is as described above. Generally, the intersection point with the oil guide groove (a) is point 11A in Figure 4.

(Problems to be Solved by the Invention) FIG. 5 shows the distribution of oil film pressure on the sliding surface. - When fishing on a boat, the minimum oil film thickness occurs on the advancing side of the rotational direction from the lowest point (point ''B 11 in Figure 5), and thereafter the oil film pressure becomes negative pressure.The pressure around the bearing in the bearing chamber, etc. Since the pressure is generally atmospheric, in areas where the oil film pressure is negative, air is sucked in from the axial end of the bearing, resulting in a mixed flow of gas (air) and liquid (lubricating oil).

- For boat fishing, the rtB" point, that is, the oil film pressure becomes negative and a mixed flow of gas and liquid occurs after about 50 to 60 degrees (β in Figure 5) from the bearing upper and lower halves of the joint surface, and this region (In Fig. 5, there is an oil groove in the center of the bearing in the "X tt area.")
exists.

Most of the loss in bearings is caused by the shearing force of the oil film, but if the oil film is a mixed flow of gas and liquid, the shearing force will be small due to the influence of the low viscosity air, and the loss will decrease. .

In this way, in the conventional bearing structure, the sliding surface (■) is a region ("X" region) where a mixed flow of gas and liquid occurs, and the oil groove (2) is filled with oil, so the terminal end of the oil groove (2) ( There is a drawback that oil flows from point A) into the oil guide groove (A), resulting in a large loss.

SUMMARY OF THE INVENTION An object of the present invention is to provide a high-speed rotation sliding bearing that can prevent self-excited vibrations of the rotor and can suck enough air into the oil guide groove.

[Structure of the invention]

(Means for Solving Problem W) The present invention provides pressure receiving pressure that generates a positive oil film pressure distribution region and a negative oil film pressure distribution region adjacent to this region on the advancing side of rotation due to external force of the shaft neck rotating at high speed. This is an improved sliding bearing that has circumferential oil grooves on its surface.

In the present invention, at least in the negative oil film pressure distribution region of the pressure receiving surface, the oil groove communicates with an oil reservoir in the vicinity of the upper and lower halves joint surface.

(Function) With this structure, the axial width of the pressure-receiving surface is made smaller than the bearing diameter by the oil groove, which not only prevents self-excited vibrations such as oil whip, but also prevents the negative oil film pressure distribution region. An oil groove is also formed in the oil guide groove portion of the oil groove, and the oil groove communicates with an oil reservoir near the upper and lower halves joint surfaces, so that the oil discharged from the oil groove in the circumferential direction is guided to the oil reservoir. That is, oil no longer flows from the oil groove to the oil guide groove, and air is sucked in from the axial end in the oil guide groove.

(Example) The present invention will be described below based on embodiments shown in the drawings.

Figures 1 and 2 show only the lower half of the plain bearing;
A recessed oil reservoir (2) is formed in each of the six divided surfaces (with the upper half omitted), and a hole (2) penetrating downward is provided in each of the oil reservoirs (0). This hole ■ serves as an oil supply hole and an oil drain hole.In the case of one hole, the rotating direction of the rotor is clockwise as shown by the arrow, so the left side of the paper is the oil supply hole and the right side is the oil drain hole. It is.

In addition, wedge-shaped oil guiding grooves (A) are provided on each dividing surface side of the sliding surface (2), which serves to facilitate supply and discharge of lubricating oil.

This sliding surface (2) is provided with an oil groove (2) extending in the circumferential direction so as to divide the sliding surface in the axial direction.

As shown in the figure, the peripheral range of this oil groove (2) ends at the oil sump 0 (point A in the figure), and the oil groove (2) and oil sump 0 communicate with each other.

Therefore, in this embodiment, the oil discharged from the oil groove (2) in the local direction is guided to the oil reservoir (2). As a result, in the negative oil film pressure distribution region explained in FIG. Therefore, the loss can be reduced.

In the above embodiment, the oil groove (2) was configured to communicate with the oil sump (2) on both sides in the circumferential direction, but the present invention is not limited to this embodiment. 0
Communication with the rotation advance side may be sufficient.

Even with this configuration, the effects of the present invention can be achieved.

Further, the oil groove (2) is not limited to one groove as in the above embodiment, but the same applies to bearings having two or more grooves.

〔Effect of the invention〕

As explained above, in the present invention, a circumferential oil groove is provided on the pressure receiving surface to prevent self-excited vibration, and this oil groove is configured to communicate with the oil reservoir on the rotation advancing side, so that negative oil film pressure can be avoided. It is possible to provide a highly stable high-speed rotation sliding bearing in which air suction is assisted in the distribution area.

[Brief explanation of the drawing]

FIG. 1 is a perspective view of the lower half of a bearing showing an embodiment of the present invention;
Figure 2 is a longitudinal sectional view of Figure 1, Figure 3 is a perspective view of the lower half of a conventional bearing, Figure 4 is a longitudinal sectional view of Figure 3, and Figure 5 shows the oil film pressure distribution state of a high-speed bearing. FIG. 1...Lower half of the bearing 2...Oil groove 3.3a...
・Slip surface agent Patent attorney Noriyuki Chika Diagram Diagram

Claims (1)

[Claims] A sliding bearing with a circumferential oil groove on the pressure receiving surface where a positive oil film pressure distribution area and a negative oil film pressure distribution area adjacent to this area on the advancing side of rotation are generated due to the external force of the shaft neck rotating at high speed. A plain bearing for high-speed rotation, characterized in that the oil groove in at least the negative oil film pressure cloth region of the pressure receiving surface communicates with an oil reservoir near the dividing joint surface of the upper and lower halves.