JPH0819944B2 - Oil film bearing - Google Patents

Description

TECHNICAL FIELD The present invention relates to an oil film bearing that supports, for example, a roll shaft of a rolling mill.

[Conventional technology]

3A and 3B are cross-sectional views of a conventional oil film bearing that supports, for example, a roll shaft of a rolling mill. In the figure, the rolling load acting on the roll body 1 of the rolling mill is transmitted to the shell 5 and the bearing box 6 through the oil film 4 through the roll shaft 3 on which the sleeve 2 is fitted, and a liner (not shown),
It is transmitted to the bearing box support portion 7 composed of a load cell, a thrust washer and the like. Roll shaft 3 sleeve 2
The high-pressure oil supply line 13 supplies high-pressure lubricating oil to form the oil film 4 so as not to make direct contact with the inner surface of the shell 5. The load capacity of such an oil-film bearing has a static pressure effect of the lubricating oil. It is created by the sum of dynamic pressure effects.

Recently, for example, rolling mills are required to have oil film bearings that can operate under extremely low speed and high load conditions. Therefore, the applicant conducted model tests and theoretical analyzes to determine the static load bearing surface. By adopting a structure that limits the pressure acting area, it has been possible to develop an oil film bearing having a bearing load capacity that is twice that of the conventional oil film bearing. FIG. 4 is a plan development view of a bearing load surface in the oil film bearing.
In the figure, the oil film bearing has four drainage grooves 16 on the bearing load surface as shown in the figure, and the high pressure lubricating oil supplied from the high pressure oil supply line passes through the recess oil supply hole 18. It is sent to the static pressure recess 11 and flows out while lowering the pressure to the low pressure part of the bearing load surface, but the length in the circumferential direction is cut off by the oil drain groove 16 with a small flow resistance and the oil pocket 19 edge
It does not reach the vicinity of 9,10. Therefore, static pressure does not act in the vicinity of the end portions 9 and 10, and the bearing load surface surrounded by the end portions 9 and 10 of the oil pocket 19 and the both end edges 14 and 15 of the oil pocket 19 is The deformation that results in a concave elliptical shape in the vertical direction is mitigated. Therefore, the reduction of the static pressure effect due to the divergence of the bearing gap can be prevented, and the bearing load capacity is improved.

In this oil film bearing, since the oil drain groove 16 is not provided in the central portion in the bearing width direction, the circumferential flow extends to the end portions 9 and 10 of the oil pocket 19 in the central portion. But,
This is because the deformation of the bearing load surface that is concave upward does not significantly affect the static pressure characteristics due to the deformation constraint of the part where static pressure does not act, and due to such a structure, the bearing width direction It is used because a large dynamic pressure effect is generated in the central part. Further, 12 is an oil supply line for dynamic pressure, 17 is an oil pocket oil supply hole, and the bearing width direction is a direction orthogonal to the circumferential direction of the bearing.

[Problems to be Solved by the Invention]

However, in the oil film bearing as described above, the relative partial contact between the roll shaft 3 and the shell 5 of the bearing housing 6 increases as the load increases, and the end portion of the roll shaft 3 on the roll body 1 side is increased. Then, the thickness of the oil film 4 is the smallest. As a countermeasure against this one-sided contact, the static pressure recesses 11 are provided in two or more places in the bearing width direction, and other measures such as lowering the frictional resistance of the bearing box bearing 7 have been taken. However, a reduction in bearing load capacity is inevitable.

Further, in the case of the present oil film bearing having the oil drain groove 16, the oil groove groove 16 and the end portions 9 and 10 of the oil pocket 19 are surrounded by the elastic deformation of the entire bearing housing 6 in addition to the influence of the above one-side contact. Part,
That is, the portion where the static pressure action is cut off comes closer to the roll shaft 3, and therefore there is a problem that the thickness of the oil film 4 becomes smaller at this portion.

[Means for solving the problem]

An oil film bearing according to the present invention is intended to solve the above-mentioned problems, and includes a hydrostatic recess provided in the vicinity of the edge of the bearing load surface and two oil pockets on the bearing load surface. Drainage grooves engraved in between,
It is characterized in that it is provided with an auxiliary static pressure recess or relief processing provided in the vicinity of the edge of the bearing load surface between the oil drain groove and the oil pocket.

[Action]

That is, in the oil film bearing according to the present invention, an oil drain groove is provided between the conventional static pressure recess and the oil pocket, and further an auxiliary static pressure recess is provided or relief processing is performed, As a result, if the oil film thickness on the bearing load surface between the oil drain groove and the oil pocket becomes smaller due to the deformation of the bearing housing, it will be in the auxiliary static pressure recess provided in this part or in the part where relief processing has been performed. Since the lubricating oil is fed and static pressure acts, the bearing box in this portion is deformed in the direction away from the roll shaft, and a required oil film thickness is secured.

〔Example〕

An embodiment of the present invention will be described with reference to FIGS. 1 and 2. It should be noted that members common to the members in FIGS. 3 and 4 are denoted by the same reference numerals as those members, and the description thereof will be omitted. FIG. 1 is a plan development view of a bearing load surface in an oil film bearing according to an embodiment of the present invention. As shown in FIGS. 1 (a) and 1 (b), the oil film bearing according to the present embodiment includes an auxiliary static pressure recess 20 between an oil drain groove 16 and ends 9 and 10 of an oil pocket 19. Is provided in the vicinity of the end 15 on the roll body side of the bearing load surface 23, and the lubricating oil sent from the high pressure oil supply line (not shown) passes through the pressure suppression oil supply hole 22, the fixed throttle 21 by the orifice, and the auxiliary static pressure recess. After flowing into the inside 20, while the pressure drops, the oil drain groove 16, the oil pocket 19,
It flows out to the end 15 on the roll body side. Note that FIG. 1 (b) shows a bb cross section of FIG. 1 (a). Further, as shown in FIG. 1 (c), two auxiliary static pressure recesses 20 may be provided on the roll end side edge 14 of the bearing load surface 23 in the same manner as the roll barrel side edge 15, and By making the surface 23 symmetrical in the bearing width direction, it is possible to prevent one-sided contact.

FIG. 2 is a plan development view of a bearing load surface in an oil film bearing according to another embodiment of the present invention. In the drawing, the oil film bearing according to the present embodiment is not provided with a recess for auxiliary static pressure as shown in the drawing, but the end of the oil drain groove 16 and the oil pocket 19 where the oil film thickness becomes small on the bearing load surface 23. Instead of providing an auxiliary static pressure recess in the portion 25 surrounded by the parts 9 and 10, the relief load 24 is applied so that the bearing load surface 23 of this portion 25 approaches the roll shaft 3 side due to the deformation of the bearing housing 6. Even so, the required oil film thickness is secured, so the bearing load capacity is improved. However, in the case of this embodiment, since the dynamic pressure effect does not occur in the portion subjected to the relief processing 24, the bearing load capacity is somewhat lower than in the case of the above embodiments. Note that FIG. 2 (b) shows a bb cross section of FIG. 2 (a).

As described above, in the oil film bearing according to the above-described two embodiments, the oil drain groove 16 is provided between the conventional hydrostatic recess 11 and the oil pocket 19, and the auxiliary hydrostatic recess 20 is further provided.
Is provided or is provided with relief processing 24, whereby the ends 9 and 10 of the oil drain groove 16 and the oil pocket 19 are provided.
When the oil film thickness on the bearing load surface 23 between and becomes small due to the deformation of the bearing housing, the lubricating oil is fed into the auxiliary static pressure recess 20 provided in this portion or the relief processed portion 24. Since static pressure acts on the bearing box, the bearing box in this portion is deformed in the direction away from the roll shaft to secure a required oil film thickness.

This is due to the interaction between the self-made throttle of the oil film thickness in this part and the fixed throttle in the recess 20 for auxiliary static pressure.
Due to the action, static pressure is hardly applied, but when the required oil film thickness is approached, the static pressure acts on the auxiliary static pressure recess 20 or the relief processed part 24 by the self-throttlement of the oil film thickness. become. However, the static pressure action of this auxiliary static pressure recess 20 is due to the oil drain groove 16 and the oil pocket 19 with a smaller oil film thickness.
Since it is limited locally between the end portions 9 and 10 and its value is small, it does not cause a concave deformation on the bearing load surface to reduce the static pressure effect by the static pressure recess 11. The required oil film thickness is determined by the processing accuracy such as the size of foreign matter in the lubricating oil that passes through the filter installed in the lubrication line, the surface roughness of the bearing load surface, waviness, and roundness. It

〔The invention's effect〕

The oil film bearing according to the present invention is configured as described above,
A necessary and sufficient oil film thickness is ensured even under a condition of extremely low speed and high load, so that an effect such as an improvement in bearing load capacity can be obtained.

[Brief description of drawings]

FIG. 1 is a plane development view of a bearing load surface in an oil film bearing according to an embodiment of the present invention, and FIG. 2 is a plane development view of a bearing load surface in an oil film bearing according to another embodiment of the present invention. FIG. 3 is a sectional view of a conventional oil film bearing, and FIG. 4 is a plan development view of a bearing load surface in an improved oil film bearing which is being studied by the present applicant. 9,10 …… End of oil pocket, 11 …… Recess for static pressure,
14 …… Roll end side edge, 15 …… Roll body side edge, 16 …… Oil groove, 19 …… Oil pocket, 20 …… Auxiliary static pressure recess, 23 …… Bearing load surface, 24 …… Escape Processing, 25 …… The part surrounded by the oil drain groove and oil pocket.

Claims (1)

[Claims] 1. A drainage groove formed between each of the two oil pockets on the bearing load surface and a recess for static pressure provided near the edge of the bearing load surface, and the drainage oil. An oil film bearing, comprising: an auxiliary static pressure recess or a relief formed near an edge of a bearing load surface between the groove and the oil pocket.