JPH0519650U - Journal bearing - Google Patents

Abstract

(57) [Summary] [Object] In a journal bearing having an arc surface of the bearing, the lubricating oil whose temperature has risen on the arc surface of the bearing runs around with the rotating shaft, resulting in an increase in the temperature of the bearing. The present invention provides a journal bearing that prevents the above. [Composition] In a journal bearing in which a cylindrical inner surface is divided into a plurality of bearing arc surfaces by oiling grooves, an axial groove is provided near the downstream end of rotation of the bearing arc surface, and a rod-shaped body is moved in the axial groove in the radial direction. Journal bearings arranged as possible.

Description

[Detailed description of the device]

[0001]

[Industrial applications]

 The present invention relates to a journal bearing to which lubricating oil is pressure-supplied from the outside.

[0002]

[Prior Art]

 As an example of the prior art, as shown in FIG. 5, a journal bearing in which a cylindrical inner surface is divided into a plurality of partial arc surfaces by an oil groove 03 for refueling is well known. The rotation of the shaft inscribed in the bearing causes oil film pressure to be generated on the partial arc surface, thereby supporting the rotating shaft 01 without the shaft coming into contact with the bearing.

[0003]

[Problems to be solved by the device]

 The above-mentioned conventional technique has the following problems. In a bearing consisting of partial arc surfaces, when the shaft surface speed of the rotating shaft increases, a portion where a high oil film pressure is distributed around the arc central portion as shown in 8 of Fig. 5 (this is caused by eccentricity of the shaft at the same time). In the region where the clearance is narrowed, there is a minimum clearance position 7 near the position where the oil film pressure drops. A part of such high temperature lubricating oil flows out from the axial end portion of the bearing, and the remaining part circulates through the minimum oil film thickness position 7. The amount of circulating oil increases as the shaft surface speed increases.

It is expected that this high-temperature oil mixes with low-temperature oil supplied from the outside in the oil groove behind the circular arc surface, reaches a sufficiently low temperature, and flows into the next circular arc surface further behind. ing. However, when the surface speed of the shaft increases, the oil dragged by the shaft and passing through the minimum oil film thickness position easily rotates with the shaft as it is, and mixing and temperature drop in the oil groove are not sufficiently performed. As a result, the temperature of the oil flowing into the next arc surface remains high and becomes narrower again, and the temperature becomes even higher due to frictional heat generation in the clearance area.

When the temperature of the lubricating oil rises, the viscosity decreases and the ability to generate high pressure decreases, so that the rotating shaft easily contacts the arc surface of the bearing. If the high-speed rotating shaft comes into contact, it will seize and stop the shaft, leading to machine failure or, in extreme cases, damage. Even if this is not the case, increased wear leads to problems such as shorter life and frequent machine inspections. These defects are the result of the temperature rise of the lubricating oil and the arcuate bearing surface in the narrowing clearance, which is further due to the lack of mixing and heat exchange between the hot circulating oil and the cold supply oil in the oil groove. Due to enough.

The present invention, in a journal bearing having a bearing arc surface, prevents the lubricating oil whose temperature has risen on the arc surface of the bearing from rotating around with the rotating shaft, resulting in an increase in the bearing temperature. It is intended to provide.

[0007]

[Means for Solving the Problems]

 (1) A groove in the axial direction is provided near the downstream end of the arc surface of the bearing, and a rod-shaped body is provided in this groove for movement. (2) Provide an oil supply hole that opens in the groove containing the rod body that is free to move in the above item (1).

[0008]

[Action]

 (1) The oil film pressure does not rise because the area near the rear end of the bearing arc surface is behind the minimum oil film thickness. There is no problem in providing the groove itself. The rod-shaped body in the axial groove is attracted to the shaft by the flow of the fluid dragged by the motion of the shaft. As a result, the gap between the rod-shaped body and the shaft surface becomes smaller than the bearing oil film thickness before and after that, and a part of the lubricating oil that circulates is obstructed to flow out in the axial direction. On the other hand, as for the lubricating oil flowing out to the next arc portion, since the amount of circulating oil decreases, the amount of cold supply oil increases, so sufficient mixing and low temperature can be expected.

(2) By opening the oil supply hole in the axial groove and pushing up the rod-shaped body by the jet flow, the scraping amount of the sea wake can be increased and the circulating amount of hot lubricating oil can be reduced. As a result, it is possible to avoid a rise in the temperature of the bearing arc surface due to an increase in the circulation amount, which is a concern when the sliding speed of the rotating shaft increases.

[0010]

【Example】

 (First Embodiment) A first embodiment of the present invention will be described with reference to FIGS. Lubricating oil is supplied to the oil supply grooves 3a and 3b through oil supply holes 9a and 9b. The relationship between the rotating shaft 1 and the bearing arc surface 2 is the same as in the conventional technique (FIG. 5). The positions where the oil film pressure is generated as shown in FIG. 5 are shifted to the downstream side, and are located slightly upstream of the oil supply grooves 3a and 3b, and axial grooves 4a and 4b are provided therein, and rod-shaped bodies are formed therein. 5a and 5b are arranged. As shown in the perspective view of FIG. 2, the rod-shaped body is free to move without being mechanically fixed or restrained. The rod-shaped bodies arranged in the axial grooves 4a, 4b may be rod-shaped bodies 15a, 15b having a short cross section, as shown in FIG.

Second Embodiment A second embodiment of the present invention will be described with reference to FIG. In the figure, the bearing arc surface 2 is divided into a plurality of bearing arc surfaces 2a and 2b by oil supply grooves 3a and 3b. Lubrication holes 9a and 9b are connected to the lubrication grooves 3a and 3b, and a lubricating oil (not shown) prepared on the outer peripheral portion of the bearing flows in. Axial grooves 4a and 4b are provided near the downstream ends of the bearing arc surfaces 2a and 2b, and rod-shaped bodies 5a and 5b are freely installed therein.

Although the above-mentioned configuration is the same as that of the first embodiment, in this embodiment, further, the oil supply holes 10a and 10b are connected to the axial grooves 4a and 4b and are provided on the outer peripheral portion of the bearing. Guides lubricating oil (not shown). During operation, the rod-shaped bodies 5a, 5b are pushed up by the jets from the oil supply holes 10a, 10b and pressed against the rotating shaft 1 to increase the scraping amount of the water wake around the rotating shaft and prevent the circulation of hot lubricating oil. To do.

[0013]

[Effect of the device]

 According to the present invention, in a journal bearing in which a cylindrical inner surface is divided into a plurality of bearing arc surfaces by an oil supply groove, an axial groove is provided near the rotation downstream end of the bearing arc surface, and a rod-shaped body is radially provided in the axial groove. The following effect can be obtained by arranging so as to be movable and providing an oil supply hole that opens at the bottom of the axial groove and pushing up the rod-shaped body in the axial groove with a jet of lubricating oil.

(1) The rod-shaped body can abut the surface of the rotary shaft to scrape off the wake flow around the rotary shaft. (2) The lubricating oil frictionally heated on the bearing sliding surface is dragged by the rotating shaft, and the amount of the lubricating oil flowing into the next sliding surface is reduced. (3) The temperature of the lubricating oil flowing into the next sliding surface can be lowered to prevent the bearing temperature from rising.

(4) It is possible to avoid the softening and strengthening of the bearing material due to the temperature rise on the arc surface of the bearing and the occurrence of seizure and wear due to the reduction of the oil film thickness.

[Brief description of drawings]

FIG. 1 is a cross-sectional view of a first embodiment of the present invention perpendicular to the axis.

FIG. 2 is a perspective view of an inner surface of the bearing shown in FIG.

FIG. 3 is a drawing similar to FIG. 1 when a rod-shaped body having a short cross section is used.

FIG. 4 is a sectional view of a second embodiment of the present invention perpendicular to the axis.

FIG. 5 is a sectional view perpendicular to the axis of a conventional journal bearing.

[Explanation of symbols]

 DESCRIPTION OF SYMBOLS 1 rotary shaft 2 bearing arc surface 3a oil supply groove 3b oil supply groove 4a axial groove 4b axial groove 5a rod-shaped body 5b rod-shaped body

Claims (2)

[Scope of utility model registration request] 1. A journal bearing in which a cylindrical inner surface is divided into a plurality of bearing circular arc surfaces by an oil supply groove, an axial groove is provided in the vicinity of a rotation downstream end of the bearing circular arc surface, and a rod-shaped body is radially arranged in the axial groove. A journal bearing, which is arranged so as to be movable to the inside. 2. The journal bearing according to claim 1, wherein an oil supply hole opening at the bottom of the axial groove is provided, and a rod-shaped body in the axial groove is pushed up by a jet of lubricating oil.