JP3364735B2 - Bearing device for contra-rotating propeller - Google Patents

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a bearing device for a counter-rotating propeller for supporting a counter-rotating propeller of a ship or the like, and particularly to a counter-rotating propeller having an improved bearing portion between an inner shaft and an outer shaft. The present invention relates to a propeller bearing device.

[0002]

2. Description of the Related Art Conventionally, in order to effectively utilize the propelling energy of a propeller, an outer shaft having a front propeller,
There is known a counter rotating propeller that is fitted in the outer shaft and rotationally drives the inner shaft having a rear propeller in mutually opposite directions.

For example, FIG. 17 is a partially cutaway side view of a conventional counter-rotating propeller 1, and FIG. 18 is an XVII of FIG.
FIG. 1 is a cross-sectional view taken along the line I-XVIII, showing a contra-rotating propeller 1
Is an outer shaft 3 having a front propeller 2 and a rear propeller 4
And the main engine 6 that drives the outer shaft 3 and the inner shaft 5 to rotate in opposite directions at a constant speed.

The outer shaft 3 is formed in a cylindrical shape, and is rotatably provided on the stern portion 7 of the ship body via an outer bearing 8 and an outer seal 9. Inner shaft 5
Are provided inside the outer shaft 3 so as to be rotatable in opposite directions via an inner bearing 10 and an inner seal 11.

A lubricating oil supply mechanism 1 for supplying lubricating oil to the outer shaft 3, the inner shaft 5, the outer bearing 8 and the inner bearing 10 is also provided.
2 is provided. A rudder horn 13 and a rudder blade 14 are provided facing the front propeller 2 and the rear propeller 4.

In the counter-rotating propeller 1 having such a structure, the outer bearing 8 between the outer shaft 3 and the stern portion 7 can adopt a normal bearing mechanism, but especially between the inner shaft 5 and the outer shaft 3. The inner bearing 10 installed on the inner side of the inner shaft 5 rotates inward.
Since the rotation directions of the outer shaft 3 and the outer shaft 3 which are reversed outward are opposite to each other, there is a problem in that the fluid slide bearing action is performed by forming an oil film by the lubricating oil from the lubricating oil supply mechanism 12.

That is, as shown in FIG. 18, the inner shaft 5 rotates clockwise, and the outer shaft 3 and the inner bearing 10 such as a slide bearing fixed to the inner peripheral surface of the outer shaft 3 rotate counterclockwise. When the outer shaft 3 and the inner shaft 5 rotate at substantially the same speed in the case of rotating, the lubricating oil between the outer peripheral surface of the inner shaft 5 and the inner peripheral surface of the inner bearing 10 forms an oil film therebetween. There is a problem that you can not do.

Therefore, there is proposed a bearing in which a tapered land portion (not shown) is provided on the inner surface of the inner bearing 10 to try to lift the inner shaft 5 by the load capacity caused by the dynamic pressure. Since the load capacity due to the dynamic pressure is small at the time of low speed or low speed rotation, the oil film becomes thin, and the inner shaft 5 and the inner bearing 10 come into metal contact with each other on the bearing surface and the inner bearing 1
There is a problem that 0 burns.

As a conventional technique for solving such a problem, for example, as shown in FIG. 19, "a stern tube bearing for counter-rotating propeller" based on a hydrostatic bearing (Japanese Patent Publication No.
45479). In this bearing, a hydraulic concentric hole 15 and a radial oil supply hole 16 extending radially from the hydraulic concentric hole 15 are formed in the inner shaft 5, and the radial oil supply hole 16 is used for forming an orifice or for capillary drawing. Insert the small hole screw 17 into the inner bearing 1 from the radial oil supply hole 16 between the inner shaft 5 and the outer shaft 3 or the inner bearing 10.
By ejecting high-pressure oil toward 0, a load capacity due to static pressure that attempts to lift the inner shaft 5 is generated to prevent uneven contact of the inner shaft 5.

However, in the case of this stern tube bearing, since the inner bearing 10 of the outer shaft 3 is a true circular bearing, when the inner shaft 5 and the outer shaft 3 are inverted at a constant speed, theoretically, this true circle is formed. The bearing does not generate load capacity due to the dynamic pressure of the lubricating oil.

Therefore, the inner shaft 5 and the outer shaft 3 (the inner bearing 1
In the case of a high rotational speed ratio in which 0) and 0) are reversed at almost the same speed, when static pressure oil supply from the radial oil supply holes 16 is lost due to blackout or failure of the oil supply pump of the lubricating oil supply mechanism 12, the oil film is There is a problem that it is not formed and is prone to baking.

Further, as described above, since the load capacity due to the dynamic pressure is insufficient at a high rotational speed ratio, the radial oil supply holes 16
Therefore, it is necessary to supply the lubricating oil by applying a relatively high static pressure, and there is a problem that the lubricating oil supply mechanism 12 becomes large.

[0013]

SUMMARY OF THE INVENTION The present invention has been made in view of the above-mentioned problems. When the inner shaft and the outer shaft rotate in the opposite directions at a substantially constant speed, or at the constant speed double inversion, or An object of the present invention is to provide a contra-rotating propeller bearing device capable of giving a load capacity especially to an inner bearing even in a state close to.

Further, according to the present invention, in the high engine speed range, the inner shaft is supported only by the load capacity due to the dynamic pressure of the lubricating oil,
A bearing device for counter-rotating propellers that can secure the load capacity by increasing the oil supply pressure and adding static pressure in the low rotation range where it is difficult to generate sufficient load capacity only with dynamic pressure The task is to do.

It is another object of the present invention to provide a bearing device for a counter-rotating propeller, which utilizes the non-round shape of the inner bearing and can generate a sufficient load capacity at a low oil supply pressure.

Another object of the present invention is to provide a bearing device for a contra-rotating propeller, which is capable of saving onboard electric power without increasing the size of the lubricating oil supply mechanism.

A further object of the present invention is to provide a bearing device for a counter-rotating propeller capable of improving the load capacity generation performance by dynamic pressure and the load capacity generation performance by static pressure as described above. .

[0018]

That is, the present invention is to generate dynamic pressure between the inner bearing and the inner shaft by making the inner peripheral surface of the inner bearing non-circular, and the non-circular shape of the inner bearing. Focusing on surrounding the part with a perfect circle,
An outer shaft having a front propeller, an inner shaft fitted in the outer shaft to be driven to rotate in a direction opposite to the outer shaft and having a rear propeller, and a bearing provided between the inner shaft and the outer shaft. And a central refueling passage and a plurality of radial refueling holes communicating with the central refueling passage, wherein the central refueling passage and the radial refueling hole are provided. Lubricating oil is supplied from the inner shaft to the inner peripheral surface of the bearing, and a plurality of uneven portions are formed on the inner peripheral surface of the bearing along the axial direction of the bearing. The bearing device for a counter-rotating propeller, characterized in that perfect circular portions are provided at both ends of the above-mentioned uneven portion.

The concavo-convex portion can be a tapered land (see FIG. 3) or a multi-arc bearing surface (see FIG. 6). The optimum number of the uneven portions can be selected depending on the bearing operating conditions, regardless of the number of radial oil supply holes.

The radial oil supply hole is L / 6 to L with respect to the length L of the bearing from the central position in the axial direction of the bearing.
The effect of static pressure oiling can be enhanced by locating this L4 rearward (see FIG. 9).

The length of the perfect circle portion is in the range of L / 48 to 24L / 48, preferably 2L, with respect to the length L of the bearing.
By setting the range of / 48 to 10 L / 48, it is possible to further improve the load capacity due to the dynamic pressure and static pressure of the lubricating oil (see FIG. 14).

In the counter rotating propeller bearing device according to the present invention, lubricating oil is supplied from the inside of the inner shaft through the radial oil supply holes to the surface of the inner bearing, and a plurality of taper lands or a plurality of tapered lands are formed on the inner peripheral surface of the inner bearing. Since the non-circular shape is formed by forming the uneven portion such as the multi-circle bearing surface, the static pressure due to the lubricating oil supplied from the inner side of the inner shaft toward the inner bearing is distributed over the inner bearing in the axial direction. It is possible to generate a load capacity that is substantially uniform.

Further, since the concavo-convex portion such as the tapered land portion or the multi-circular bearing surface is formed, the load capacity due to the dynamic pressure is generated between the inner shaft and the inner bearing irrespective of the rotation speed ratio. There is no need to increase the static pressure from the radial oil supply holes.

As a result, even when the load capacity cannot be generated by static pressure due to the lack of refueling at the time of blackout, or when the propeller is in a low speed idling state, Even if the shaft and outer shaft rotate at a high speed ratio where they rotate at almost the same speed, load capacity can be generated by dynamic pressure regardless of the speed ratio, so shaft seizure is avoided and safety is ensured. It is possible to improve the sex.

Further, since the non-circular shape of the inner bearing is surrounded by the perfect circular portions formed at both ends of the concave-convex portion, the lubricating oil in the concave-convex portion hardly leaks to the outside effectively. Can be pivotally supported, and the dynamic pressure performance and static pressure performance of generating load capacity can be further improved.

[0026]

BEST MODE FOR CARRYING OUT THE INVENTION Next, a bearing device for a counter rotating propeller according to an embodiment of the present invention will be described with reference to the drawings. However, the same parts as those in FIGS. 17 to 19 are designated by the same reference numerals, and the detailed description thereof will be omitted.

FIG. 1 is a sectional view of the counter-rotating propeller shaft system 20 and its bearing device 21, and FIG. 2 is a line II-II in FIG.
As shown in FIG. 1, the contra-rotating propeller shaft system 20 has an outer shaft 22 having a front propeller 2 and an inner shaft 23 having a rear propeller 4 as shown in FIG. 1.

The outer shaft 22 is formed in a cylindrical shape and is rotatably provided through the outer bearing 8 integrally with the front propeller boss 24 of the front propeller 2 and the connecting member 25. is there.

The inner shaft 23 is arranged inside the outer shaft 22 via an inner bearing 26, and the rear propeller boss 2 of the rear propeller 4 is engaged.
It is provided integrally with 7 so as to be rotatable in the direction opposite to the outer shaft 22.

The inner shaft 23 and the inner bearing 26 are provided with the counter rotating propeller bearing device 21 of the present invention.
That is, the central oil supply passage 28 is formed in the central axis direction of the inner shaft 23, and the lubricating oil is supplied from the lubricating oil supply mechanism 12 at a predetermined pressure.

As shown in FIG. 2, a plurality of radial oil supply holes 29 (one row in the axial direction as shown in FIG. 1) are provided in a portion communicating with the central oil supply passage 28 and facing the inner bearing 26 of the inner shaft 23. In addition, as shown in FIG. 2, eight radial oil supply holes 29) are formed in the cross-section portion perpendicular to the axial direction, that is, eight radial oil supply holes 29) are formed in one inner shaft 23, and the outer peripheral surface of the inner shaft 23 and the inner bearing are formed. Lubricating oil can be supplied to the bearing surface between the inner peripheral surface of 26.

A part of the lubricating oil supplied to the bearing surface passes through the axial oil passage 30 of the inner bearing 26, the cylindrical passage 32 between the isolating cylindrical member 31 and the inner shaft 23,
The oil flows through the diametrical communication hole 33 of the isolating cylindrical member 31 and the oil drain hole 34 of the outer shaft 22 to the tank (not shown) of the lubricating oil supply mechanism 12 from the outlet 35 of the stern portion 7.

Of the lubricating oil supplied to the bearing surface, the lubricating oil flowing in the direction of the cylindrical passage 32 merges with the above-mentioned part of the lubricating oil to form a diametrical communicating hole between the cylindrical passage 32 and the isolating cylindrical member 31. 33, the oil drain hole 34 of the outer shaft 22, and the drain port 35 of the stern portion 7 flow back to the tank.

Next, the bearing device 21 portion of the counter-rotating propeller of the present invention will be described with reference to FIGS. As shown in FIG. 2, the bearing device 21 for the counter-rotating propeller
In the inner peripheral surface of the inner bearing 26, tapered lands 42 formed by alternately arranging the curved tapered surfaces 40 and the land surfaces 41 are formed on the surface perpendicular to the axial direction at equal angular intervals over the entire circumference. .

The curved tapered surface 40 is formed in a recess shape by an arc having a curvature smaller than that of the outer peripheral surface of the inner shaft 23. The land surface 41 is formed concentrically with the outer peripheral surface of the inner shaft 23 and in a perfect circular shape.

FIG. 3 is a cross-sectional view showing the curved tapered surface 40 and the land surface 41 more specifically, and dividing points at equal center angles on the circumference of an arbitrary radius R1 from the center of the inner bearing 26. By further forming a circle with a radius R2 around (in the figure, eight locations), a curved tapered surface 40 is formed on the inner peripheral surface of the inner bearing 26 while leaving the land surface 41.

By arbitrarily selecting and combining the radii R1 and R2, it is possible to obtain the curved taper surface 40 having a predetermined shape and depth and the land surface 41 having a predetermined length.

The radius of the inner shaft 23 is R, and the gap (radial clearance) between the outer peripheral surface of the inner shaft 23 and the inner peripheral surface of the inner bearing 26 is C.
Then, the maximum depth H of the curved tapered surface 40 is R1.
It becomes + R2- (R + C).

The maximum depth H of the curved tapered surface 40 may vary slightly depending on the number of bearing pads, that is, the number of tapered lands 42, operating conditions, etc., but is 1.0 to 3.0 × diameter of the inner bearing 26. It is about / 10,000.

FIG. 4 is a development view of the inner peripheral surface of the inner bearing 26, showing the curved tapered surface 40 of the tapered land 42.
And land surfaces 41 are alternately formed. However, on both axial end portions (left and right sides in FIG. 4) of the tapered land 42, on the same circumferential surface as the land surface 41, around the circumference,
A rear side land surface 41B (left side in FIG. 4) and a front side land surface 41F (right side in FIG. 4) having a radius of about (R + C) are formed as a circular portion (land surface) in the circumferential direction of a predetermined length. There is.

That is, on the inner peripheral surface of the inner bearing 26, the curved tapered surface 40 is formed by the pair of circumferential land surfaces 41 and the axial rear side land surface 41B and front side land surface 41F. It is in a state of being surrounded by parts.

For comparison with FIG. 4, FIG. 5 shows the tapered land 42 in which the rear land surface 41B and the front land surface 41F are not formed (the entire surface is a tapered land) of the inner bearing 26. It is a development view of an inner peripheral surface.

FIG. 6 is a sectional view similar to FIG. 3, showing another example of the non-round shape on the inner peripheral surface of the inner bearing 26.
The configuration for forming the non-round shape similar to the taper land 42 is slightly different from the case of FIG. The inner peripheral surface of the inner bearing 26 is equally divided (e.g., into eight equal parts), and a recess is formed in the inner peripheral surface between these adjacent equal points.

That is, of the points (eight locations in the figure) divided into equal central angles on the circumference of an arbitrary radius R1 from the center of the inner shaft 23, two circles having a radius R3 with two adjacent points as centers are further circled. A multi-arc bearing surface 43 (recess) corresponding to the taper land 42 is formed between the equal points where these arcs intersect the inner peripheral surface and are adjacent to each other.
To a predetermined depth and shape. By arbitrarily selecting and combining the radii R1 and R3, it is possible to obtain the multi-arc bearing surface 43 having a predetermined shape and depth.

FIG. 7 is a development view of the inner peripheral surface of the inner bearing 26, in which a multi-arc bearing surface 43 is formed in the circumferential direction.
However, on both sides of the multi-circular bearing surface 43 in the axial direction (on the left and right sides in FIG. 7), as in FIG. 4, on the same circumferential surface as the land surface 41, a circumference of a circle, a circumference of a predetermined length. As a true circle portion (land surface) in the direction, a rear land surface 41B (left side in FIG. 7) and a front land surface 41F having a radius of about (R + C).
(Right side in FIG. 7) is formed.

That is, on the inner peripheral surface of the inner bearing 26, the multi-circle bearing surface 43 is the rear land surface 41 in the axial direction.
The left and right ends in the axial direction are surrounded by B and the front side land surface 41F.

For comparison with FIG. 7, FIG. 8 shows the multi-circular bearing surface 43 in a state where the rear side land surface 41B and the front side land surface 41F are not formed (the whole surface is a multi-circular bearing surface). FIG. 6 is a development view of an inner peripheral surface of an inner bearing 26.

As the total length T (the axial direction of the inner bearing 26) of the above-mentioned rear land surface 41B and front land surface 41F in the inner circumferential direction of the inner bearing 26 shown in FIG. 4 and FIG. In consideration of improving dynamic pressure performance and static pressure performance by oil, the range of 2L / 48 to 10L / 48 is appropriate for the axial length L of the inner bearing 26 (described later based on FIG. 14). To).

FIG. 9 shows a bearing device 21 for a contra-rotating propeller.
10 is a sectional view taken along line XX of FIG. 9, and the formation position of the radial oil supply holes 29, that is, the optimum position of the oil supply cross section is determined by the weight of the propeller (rear propeller 4) and the diameter of the inner shaft 23. Although it depends on the above, generally, when it is moved backward by L / 6 to L / 4 from the center position of the inner bearing 26 (leftward in FIG. 9), the effect of static pressure oil supply is enhanced.

FIG. 11 shows the inner shaft 23 and the inner bearing 2.
6 is an essential part cross-sectional view showing an end portion of No. 6, and when the relative inclination angle with the inner shaft 23 at the end portion of the inner bearing 26 is large,
Since the local hit becomes large, by processing the trumpet-like inclined portion 26A at the end of the inner bearing 26, this relative inclined state can be alleviated.

FIG. 12 is a graph showing the relationship between the rotational speed of the inner shaft 23 and the minimum oil film thickness (load capacity). When the inner shaft 23 and the inner bearing 26 rotate at a high speed, Since sufficient load capacity is generated by dynamic pressure, the required oil film thickness can be obtained, and the oil supply pressure can be reduced to the limit at which the temperature rise of the lubricating oil is allowed. In the figure, the "maximum rotation speed" is the continuous maximum output rotation speed, that is, the rotation speed at the rated output.

Further, when the engine is operated in a low rotation range where the load capacity due to dynamic pressure is insufficient, the load capacity due to static pressure is controlled to increase.

However, if the oil supply pump (not shown) of the lubricating oil supply mechanism 12 is operated for a long time in the vicinity of the rotation speed at which it is "ON / OFF", the rotation speed slightly fluctuates due to sea conditions (sea weather conditions). Always turn on the refueling pump "ON"
/ OFF ”, so as shown in FIG.
When the shaft speed rises, it passes through the path of A-B-C-D-E, and when the shaft speed falls, it carries out operation control that draws hysteresis like E-D-F-B-A. If the oil pump is turned "ON", it will be "OFF" even if the rotation speed increases a little.
Design not to.

FIG. 13 is a graph showing the relationship of the minimum oil film thickness (load capacity) with respect to the rotation speed ratio, ( outer shaft rotation speed / inner shaft rotation speed) × 100. When both the inner shaft 5 and the outer shaft 3 are perfect circles as shown in FIG. 19 as a conventional example, the action of the lubricating oil carried by the inner shaft 5 and the outer shaft 3 which are reversed to each other is offset, so that the inner shaft 5 and the outer shaft 3 are completely opposite to each other. When it is reversed at a constant speed, the load capacity becomes zero.

However, as in the present invention, the inner bearing 2
By forming a plurality of uneven portions or non-round portions such as the tapered land 42 or the multi-circular bearing surface 43 on the shaft 6, even if the inner shaft 23 and the outer shaft 22 rotate in opposite directions, Due to the new gap between the inner bearing 26 and the inner bearing 26, it is possible to newly generate a load capacity due to the dynamic pressure accompanying the shaft rotation.

Therefore, as shown by the dotted line in FIG.
In a region where the rotational speed ratio is low, the true circular bearing has a higher load capacity due to dynamic pressure, but in the region where the rotational speed is high and the propeller propulsion efficiency of the counter-rotating propeller shaft system 20 is high, the tapered land 42 or the multi-arc bearing is used. It can be seen that the inner bearing 26 having the surface 43 has a higher load capacity due to dynamic pressure.

It should be noted that the rear land surface 41B and the front land surface 41B and the front land surface 41F shown in FIGS. 5 and 8 are not formed (solid line in the figure), as shown in FIGS. 4 and 7. In the case of the present invention in which the side land surface 41F is formed, the minimum oil film thickness can be increased.

That is, the uneven portion such as the tapered land 42 (FIG. 4) or the multi-arc bearing surface 43 (FIG. 7) is
Since the axial direction of the inner bearing 26 is blocked by the rear land surface 41B and the front land surface 41F,
Lubricating oil is effectively stored in the uneven portion, and the efficiency of generating load capacity due to dynamic pressure and static pressure is improved.

FIG. 14 is a graph showing the relationship between the oil film thickness and the length of the rear land surface 41B and the front land surface 41F (total length T). In the range where the maximum value of the oil film thickness appears, the total length T is L / L with respect to the axial length L of the inner bearing 26.
The range is 48 to 8 L / 48. Further, when static pressure is applied, the range in which the maximum value of the oil film thickness appears is the range in which the total length T is 4 L / 48 to 24 L / 48. Therefore,
A preferable range is L / 48 (the length corresponding to the minimum value when only the dynamic pressure is applied) to 24 L / 48 (the length corresponding to the maximum value when the static pressure is applied).

However, as shown in the figure, when only the dynamic pressure is applied, the oil film thickness becomes thin, and when it deviates from the maximum value, it becomes even thinner. Therefore, as a more preferable range of the total length T of the rear land surface 41B and the front land surface 41F, normally, an intermediate value when only the dynamic pressure and the static pressure are applied is set to 2.5 L. / 48
Although it can be set to ˜16 L / 48, in order to secure a certain oil film thickness even when only the dynamic pressure is obtained, considering the influence degree on the dynamic pressure side in the above range to be large, The more preferable range is 2 L / 48 to 10 L /
It can be 48.

Next, the load capacity due to static pressure and the hydraulic pressure of lubricating oil will be described with reference to FIGS. 15 is similar to FIGS. 2 to 3, but with the inner shaft 2
3 is a sectional view of the inner bearing 26 slightly eccentric,
FIG. 16 is a graph showing the relationship between the rotational speed ratio and the oil film thickness, and shows the load capacity due to dynamic pressure and static pressure.

As shown in FIG. 15, the lubricating oil supply pressure PS
On the other hand, the pressure of the inner bearing 26 passes through the small hole screw 17 for forming the orifice or for forming the capillary tube, and the inner shaft 23
On the lower surface of the inner shaft 23 and P2 on the upper surface of the inner shaft 23.

When the distance between the outer peripheral surface of the inner shaft 23 and the inner peripheral surface of the land surface 41 portion of the inner bearing 26 is H1 on the lower surface and H2 on the upper surface, the centers of the inner shaft 23 and the inner bearing 26 coincide with each other. When doing, H1 = H2 and screw with small hole 1
The resistance of the throttle by 7 and the resistance of the throttle in the bearing gap become equal and P1 = P2, so the load capacity becomes zero.

When the inner shaft 23 is eccentric and sinks downward in the figure by the eccentric distance e, H1 <H2 and P2 <P1 are satisfied,
A load capacity is generated by this differential pressure (P1-P2).

As shown in FIG. 16, the inner shaft 23 having a non-round shape such as the tapered land 42 or the multi-circular bearing surface 43 in the present invention has a higher load capacity due to dynamic pressure, and therefore a lower feed rate. An equivalent load capacity can be obtained by hydraulic pressure, and the oil supply pressure can be reduced as compared with the perfect circular bearing shown in FIG.

[0066]

As described above, according to the present invention, a taper land or a multi-arc bearing surface having a non-round shape is provided on the inner peripheral surface of the inner bearing, and further, for example, a rear land surface and a front land surface. Since the circular portion is formed, the load capacity due to the dynamic pressure can be positively and effectively generated, and the oil supply pressure can be suppressed to be low.

Therefore, the static pressure oil supply from the lubricating oil supply mechanism is unnecessary or low pressure is required, so that the electric power onboard the ship can be saved.

Also, when static pressure oil supply is not performed at the time of blackout and the front and rear propellers are in a low speed idling state, load capacity is generated by dynamic pressure regardless of the rotation speed ratio. Therefore, it is possible to improve the seizure resistance and the safety as compared with the case of the perfect circular bearing structure.

[0069]

[Brief description of drawings]

FIG. 1 is a sectional view of a counter-rotating propeller shaft system 20 equipped with a counter-rotating propeller bearing device 21 according to an embodiment of the present invention.

FIG. 2 is a sectional view taken along line II-II of FIG.

[FIG. 3] Similarly, a curved tapered surface 40 and a land surface 41
It is sectional drawing which shows the (taper land 42) more concretely.

FIG. 4 is a development view of a tapered land 42 on the inner peripheral surface of the inner bearing 26 of the same.

FIG. 5 is a development view of the inner peripheral surface of the inner bearing 26 when the rear land surface 41B and the front land surface 41F are not formed.

FIG. 6 is a sectional view similar to FIG. 3, showing another example (multi-circle bearing surface 43) of a non-round shape on the inner peripheral surface of the inner bearing 26.

FIG. 7 is a development view of a multi-circle bearing surface 43 on the inner peripheral surface of the inner bearing 26.

FIG. 8 is a development view of the inner peripheral surface of the inner bearing 26 when the rear land surface 41B and the front land surface 41F are not formed.

FIG. 9 is a sectional view of a bearing device 21 portion for a counter-rotating propeller of the same.

10 is a sectional view taken along line XX of FIG.

FIG. 11 is a sectional view of relevant parts showing the ends of the inner shaft 23 and the inner bearing 26 of the same.

FIG. 12 is a graph showing the relationship between the minimum oil film thickness (load capacity) and the rotation speed of the inner shaft 23.

FIG. 13 is a graph showing a relationship between a minimum oil film thickness and a rotation speed ratio.

FIG. 14 is a graph showing the relationship between the oil film thickness and the total length T) of the rear land surface 41B and the front land surface 41F.

FIG. 15 is the same as FIG. 2 to FIG. 3, except for the inner shaft 2;
3 is a cross-sectional view when 3 is slightly eccentric with respect to the inner bearing 26. FIG.

FIG. 16 is a graph showing the relationship between the oil film thickness and the rotation speed ratio.

FIG. 17 is a partially cutaway side view of a conventional counter-rotating propeller 1.

FIG. 18 is a sectional view taken along line XVIII-XVIII of FIG.

FIG. 19 is a sectional view of essential parts of a conventional stern tube bearing for a counter-rotating propeller based on a static pressure true circular bearing.

[Explanation of symbols]

1 Double reversal propeller (Fig. 17) 2 Front propeller 3 Outer shaft 4 Rear propeller 5 Inner shaft 6 Main engine 7 Stern part of ship body 8 Outer bearing 9 Outer seal 10 Inner bearing 11 Inner seal 12 Lubricating oil supply mechanism 13 Rudder horn 14 rudder plate 15 hydraulic concentric hole 16 radial oil supply hole 17 screw with small hole for orifice formation 20 counter-rotating propeller shaft system (Fig. 1) 21 counter-rotating propeller bearing device (Fig. 1) 22 outer shaft 23 inner shaft 24 Front propeller boss 25 Connecting member 26 of outer shaft 22 Inner bearing 26A Trumpet-shaped inclined portion 27 of inner bearing 26 Rear propeller boss 28 Central oil supply passage 29 Radial oil supply hole 30 Axial oil passage 31 of inner bearing 26 Cylindrical member 32 for isolation Cylindrical passage 33 Diameter communication hole 34 of separating cylindrical member 31 Oil drain hole 35 of outer shaft 22 Discharge port 40 of stern portion 7 Curved tapered surface 41 41B Rear land surface (circular circumferential true circle portion) (FIGS. 4 and 7) 41F Front side land surface (circular circumferential true circle portion) (FIGS. 4 and 7) 42 Tapered land (curved surface tapered surface) 40 and land surface 41) (concavo-convex portion) (Figs. 2 and 3) 43 multi-arc bearing surface (concavo-convex portion) (Figs. 6 and 7) C Outer peripheral surface of inner shaft 23 and inner peripheral surface of inner bearing 26 Gap (radial clearance) H with depth of the curved tapered surface 40 R radius of the inner shaft 23 R1 inner shaft 23 for forming the curved tapered surface 40
Radius R2 from center of radius R1 for forming curved tapered surface 40
Radius R3 from a point on the circumference of R3 Arbitrary radius from a point on the circumference of radius R1 to form the multi-circle bearing surface 43 L Axial length of the inner bearing 26 Rear land surface 41B and front land surface 41F
Total pressure PS of lubricating oil P1 pressure P2 on the lower surface of the inner shaft 23 pressure H1 on the upper surface of the inner shaft 23 outer peripheral surface of the inner shaft 23 and land surface 41 of the inner bearing 26
Distance H2 on the lower surface between the inner peripheral surface of the portion and the outer peripheral surface of the inner shaft 23 and the land surface 41 of the inner bearing 26
Eccentric distance that the inner shaft 23 is eccentric with respect to the inner bearing 26

─────────────────────────────────────────────────── ─── Continuation of the front page (73) Patent holder 000005119 Hitachi Zosen Corporation 1-89 Minami Kohoku, Suminoe-ku, Osaka-shi, Osaka (73) Patent holder 000005902 Mitsui Engineering & Shipbuilding Co., Ltd. 5 Tsukiji, Chuo-ku, Tokyo 6-4 (72) Inventor Shinichi Otani 3-1-1 Higashikawasaki-cho, Chuo-ku, Kobe City, Hyogo Prefecture Kawasaki Heavy Industries, Ltd. Inside the Kobe Factory (72) Inventor Keiichi Nitta 19 Natsushima-cho, Yokosuka-shi, Kanagawa Sumitomo Heavy Industries Machinery Industry Co., Ltd. Oppama Shipyard (72) Inventor Masayasu Matsuda 19 Natsushima-cho, Yokosuka City, Kanagawa Sumitomo Heavy Industries Co., Ltd. Oppama Shipyard (72) Inventor Satoshi Keirinbo 1-2-2 Marunouchi, Chiyoda-ku, Tokyo No. Nippon Steel Tube Co., Ltd. (72) Inventor, Mr. Kaoru Ashida No. 5-3-8 Nishikujo, Konohana-ku, Osaka City, Osaka Prefecture Hitachi Shipbuilding Co., Ltd. ( 72) Inventor Hideki Shibuya 1 Yawata Kaigan Dori, Ichihara City, Chiba Mitsui Engineering & Shipbuilding Co., Ltd., Chiba Works (56) Reference JP 61-236921 (JP, A) JP 7-69292 (JP, A) Japanese Patent Publication 5-45479 (JP, B2) Japanese Patent Publication 47-37919 (JP, B1) Japanese Publication 46-6926 (JP, B1) Japanese Publication 48-4500 (JP, B1) (58) Fields investigated (Int.Cl. ⁷ , DB name) B63H 23/32 B63H 5/10

Claims (4)

(57) [Claims] 1. An outer shaft having a front propeller, an inner shaft fitted in the outer shaft to be rotationally driven in a direction opposite to the outer shaft and having a rear propeller, and the inner shaft and the outer shaft. A bearing device for a counter-rotating propeller having a bearing provided therebetween, wherein a central oil supply passage and a plurality of radial oil supply holes communicating with the central oil supply passage are formed in the inner shaft. Lubricating oil is supplied from the inner shaft to the inner peripheral surface of the bearing through the passage and the radial oil supply hole, and a plurality of uneven portions are formed on the inner peripheral surface of the bearing along the axial direction of the bearing. Formed at equal angular intervals over the entire circumference, and further, by providing a true circle portion at both ends of the uneven portion in the axial direction of the bearing, the inner shaft and the uneven portion sandwiched by the true circle portion Between
Generated on the inner peripheral surface of the bearing due to the lubricating oil in
Load capacity is uniform over the axial direction of the bearing
This is a bearing device for counter-rotating propellers. 2. The bearing device for a counter-rotating propeller according to claim 1, wherein the uneven portion has a tapered land or a multi-arc bearing surface. 3. The radial oil supply hole is L / L relative to a length L of the bearing from a central position in the axial direction of the bearing.
The bearing device for a counter-rotating propeller according to claim 1, wherein the bearing device is located rearward by 6 to L / 4. 4. The length of the perfect circle portion is set in a range of L / 48 to 24L / 48, preferably in a range of 2L / 48 to 10L / 48 with respect to a length L of the bearing. The bearing device for a counter-rotating propeller according to claim 1.