JPH0515599B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION [Field of Industrial Application] The present invention relates to a bearing device installed between the inner and outer shafts of a counter-rotating marine propeller driven by inner and outer shafts that are opposite to each other.

[Conventional technology]

A conventional technique related to a hydrostatic inner shaft bearing for a counter-rotating propeller shaft of a ship will be explained based on FIG. FIG. 8 is a sectional view of a stern tube bearing as an embodiment of the invention previously filed by the applicant as Japanese Patent Application No. 1983-250471. The outer shaft 12' and the outer shaft bearing 16' that drive the front propeller shown in the figure have the same structure as before, but the center of the inner shaft 11' that drives the rear propeller is supplied with high-pressure oil from a hydraulic source (not shown). An oil guide hole 13' extending along the axial direction is connected to a plurality of oil supply holes 1 provided radially on the inner shaft 11'.
4'. A fluid restricting element 15' such as an orifice is tightened into the opening of the oil supply hole 14', that is, the oil supply hole 14' near the outer circumference of the inner shaft 11', and fluid is supplied between the inner shaft 11' and the outer shaft 12'. The amount of lubricating oil can be adjusted. Further, the outer periphery of the orifice etc. is finished to be flush with the outer periphery of the inner shaft 11'.

[Problem to be solved by the invention]

However, the conventional device shown in FIG. 8 has the following problems.

(1) Inner shaft 1 that rotates in the opposite direction at approximately the same speed as outer shaft 12'
In the case of a so-called hydrostatic inner shaft bearing, in which high-pressure oil is supplied from oil supply holes 14' provided radially in the inner shaft 1', the inner shaft 11' floats above the outer shaft 12' by the oil pressure, and lubrication is established. Unlike the hydrostatic stern tube bearings of normal single-shaft ships, which have one or two oil supply pockets at the bottom of the bearing, due to its structure, it is necessary to flow more lubricating oil than is required for load bearing. There must be sufficient oil drainage passage after lubrication.

(2) The above-mentioned hydrostatic inner shaft bearing relies on an external hydraulic power source to generate and supply high-pressure oil to support the load, so there is no mechanism for maintaining lubrication in the unlikely event that the hydraulic power source is lost due to a power outage, etc. There is a risk of metal contact between the sliding surfaces of the inner and outer shafts.

Although such devices are required to avoid catastrophic damage under such conditions, conventional locations cannot completely satisfy this requirement.

(3) As a countermeasure to prevent metal contact between the sliding surfaces of the inner and outer shafts, it may be possible to press-fit a bearing metal bushing into the inner peripheral surface of the outer shaft corresponding to the oil supply hole of the inner shaft. If this is done alone, there is a concern that the high-pressure oil ejected from the oil supply hole of the inner shaft will collide with the soft bearing metal, causing erosion of the bearing metal due to solid particles contained in the oil.
In particular, in the case of bearings with counter-rotating shafts, as the inner shaft rotates, the inner circumferential surface of the bearing metal corresponding to the oil supply hole is constantly bombarded with jets over the entire circumference, which is a factor that accelerates erosion. Random.

In order to solve the above-mentioned problems, the present invention provides an inner shaft bearing whose inner peripheral surface is covered with bearing metal, which is fitted onto the inner peripheral surface of the outer shaft, so that even in the unlikely event that the metal between the sliding surfaces of the inner and outer shafts A plurality of oil drain holes are provided on the outer peripheral surface of the inner shaft bearing in contact with the outer shaft and/or on the inner peripheral surface of the outer shaft to avoid contact and communicate with both ends of the inner shaft bearing in the axial direction,
Ensure a sufficient oil drainage passage after lubrication, and install fluid restricting elements such as orifices in the oil supply hole l/d>
An object of the present invention is to provide a bearing device for a counter-rotating propeller shaft for a ship, which is arranged at a position of 25 and prevents erosion of the bearing metal.

[Means to solve the problem]

For this reason, the bearing device for a counter-rotating propeller shaft for a ship of the present invention has an oil guide hole extending in the axial direction at the inner shaft core of the counter-rotating propeller shaft system. In a bearing device that is equipped with an oil supply hole that communicates with the outer peripheral surface, and is configured to supply lubricating oil from the oil supply hole to support the outer shaft on the outer peripheral surface of the inner shaft, the outer shaft corresponding to the opening position of the oil supply hole An inner shaft bearing that is fitted onto the inner peripheral surface and has a bearing metal stretched over the inner peripheral surface, and has an oil drain hole provided on the outer peripheral surface of the inner shaft bearing or on the inner peripheral surface of the outer shaft, and has an oil supply amount. The position where the adjustment orifice or a fluid restriction element with the same function is l/d > 25 of the oil supply hole, where l is the distance from the installation position of the fluid restriction element to the outer circumferential surface of the inner shaft, and d is the fluid restriction element. It is characterized by being arranged in the diameter of the flow path provided in the.

[Effect]

(1) After lubricating the bearing, the lubricating oil is smoothly drained through the oil drain hole provided on the outer circumferential surface of the inner shaft bearing and/or the inner circumferential surface of the outer shaft.

Even in the unlikely event that metal contacts occur between the sliding surfaces of the inner and outer shafts, the bearing metal acts to prevent catastrophic damage.

(2) Since the installation depth of the orifice, etc. in the radial oil supply hole of the inner shaft is set to a value greater than the required value, erosion of the bearing metal due to the jet flow of high-pressure lubricating oil is eliminated.

〔Example〕

Below, the bearing device for a contra-rotating propeller shaft for ships according to the present invention will be explained with reference to the drawings.
Fig. 7 shows an embodiment of the device of the present invention, Fig. 1 is a longitudinal sectional view of the stern shaft system, Fig. 2 is a partially enlarged view of Fig. 1, and Fig. 3 is a view taken in the direction of the arrow in Fig. 2. A partial cross-sectional view of the inner shaft at the oil supply hole position indicated by -, and FIGS. 4 to 7 are cross-sectional views of the inner shaft bearing provided on the inner circumferential surface of the outer shaft.

In the figure, 1 is the inner shaft, 2 is the outer shaft, 3 is the rear propeller,
4 is a front propeller, 5, 6, 7, 8 are seal devices, 9 is a hollow shaft split in two, 10 is an outer shaft joint, 1
1 is the bow side inner shaft bearing, 12 is the bow side outer shaft bearing, 1
3 is the stern side outer shaft bearing, 14 is the stern side inner shaft bearing, 1
5 is a rope guard, 16 is a hull, 17 is a rear bulkhead of the engine room, 18 is an oil guide hole for passing high pressure oil a, 1
9 is an oil supply hole provided radially on the inner shaft 1, 20 is an oil drain hole provided on the outer shaft, 21 is a lubricating oil outlet pipe,
14-1 is the tensioned bearing metal of the stern inner shaft bearing 14, 14-2, 14-3, 14-4, 14-
Reference numeral 5 indicates an oil drain hole provided in at least one of the outer circumferential surface of the inner shaft bearing 14 or the inner circumferential surface of the outer shaft 2, and communicates both ends of the inner shaft bearing.

Of course, the bow side inner shaft bearing 11 is also provided with a bearing metal and an oil drain hole.

The inner shaft 1 is connected to a propulsion motor (not shown) and drives a rear propeller 3. Further, the outer shaft 2 is rotated in the opposite direction to the inner shaft 1 by a reversing device or a second propulsion motor (not shown), and drives the front propeller 4.

In addition, the lubricating oil that lubricates the inner and outer shaft bearings 11, 12, 13, and 14 is the inner shaft 1 that drives the rear propeller 3.
High-pressure oil is introduced from a hydraulic source (not shown) into an oil guide hole 18 extending in the axial direction on the axis of the oil guide hole 1.
8, the inner shaft bearings 11 and 14 are supplied with oil through a plurality of oil supply holes 19 provided radially in the inner shaft 1, and the oil is drained after lubrication either directly or provided on the outer periphery of the inner shaft bearings 11 and 14. The oil passes through the oil drain holes 11-2 and 14-2, passes through the oil drain hole 20 drilled in the outer shaft 2, lubricates the outer shaft bearings 12 and 13, and then returns to the oil pressure source from the lubricating oil outlet pipe 21.

Examples of installing oil drain holes are shown in FIGS. 4 to 7, but as shown in FIG.
It may be provided so as to penetrate through the inside of 4.

In order to adjust the amount of oil supplied to the inner shaft bearings 11 and 14, the oil supply hole 19 is provided with an orifice or a fluid restricting element (hereinafter simply referred to as an orifice) having the same function as the orifice, as shown in FIG. This explains the required value of the set depth of this orifice.

The setting depth of this orifice is orifice 30.
Inner shaft bearing 11,1 by lubricating oil spouted from
This was obtained based on the results of a collision erosion test of the bearing metal 14-1 etc. stretched on the inner circumferential surface of No. 4.

As shown in FIG. 9, if the ratio l/d of the installation depth and diameter of the orifice 30 is small, wear due to erosion is inevitable even in the case of clean oil. Please refer to Figure 3 for l and d. Furthermore, when solid particles are mixed in, the amount of wear increases rapidly as shown in FIG. However, when l/d is increased, the amount of wear decreases significantly, and in the region of l/d>25, the amount of wear becomes almost zero in any case. In this way, if the orifice 30 is provided at the position of the oil supply hole 19 as proposed in the present invention, bearing metal will be formed on the inner peripheral surface of the inner shaft bearings 11 and 14 regardless of the amount of solid particles mixed in the lubricating oil. Even if the bearing metal is provided, damage caused by erosion that occurs in the bearing metal can be avoided.

〔Effect of the invention〕

As detailed above, according to the counter-rotating propeller bearing device for ships of the present invention, (1) an inner shaft bearing having the following structure is fitted onto the inner peripheral surface of the outer shaft.

a. Has a bearing metal on the inner peripheral surface.

b. A plurality of oil drain holes are provided on the outer peripheral surface in contact with the outer shaft or on the inner peripheral surface of the outer shaft, connecting both ends of the inner shaft bearing in the axial direction.

(2) If the diameter of an orifice for adjusting the amount of oil supply or a fluid restriction element with the same function is d and its installation depth is l, install the fluid restriction element in the oil supply hole so that l/d > 25. do.

(1) A hydrostatic inner shaft that is applied to counter-rotating marine propeller shaft systems that solves problems with oil drainage, reliability when the inner and outer shafts contact, and resistance to bearing metal erosion of the inner shaft bearing. Bearing reliability can be improved.

(2) In addition, by adopting a hydrostatic inner shaft bearing, the inner shaft diameter can be made smaller than that required for a hydrodynamic inner shaft bearing.
This is very advantageous in terms of placement and economy.

(3) Furthermore, favorable low-speed operation becomes possible due to the larger propeller and improved propulsion efficiency.

This provides advantages such as:

[Brief explanation of the drawing]

FIG. 1 is a longitudinal sectional view of a stern shaft system equipped with an embodiment of the bearing device for a contra-rotating propeller shaft for ships according to the present invention, FIG. 2 is a partially enlarged view of FIG. 1, and FIG.
A partial sectional view of the inner shaft indicated by the arrow - in the figure, and FIGS. 4 to 7 are sectional views showing various embodiments of the inner shaft bearing of the present device. FIG. 8 is a sectional view of a conventional inner shaft bearing. Furthermore, FIG. 9 shows experimental results showing the influence of the installation depth of the orifice on the wear depth of the bearing metal. 1... Inner shaft, 2... Outer shaft, 3... Rear propeller, 4... Front propeller, 5, 6, 7, 8... Seal device, 9... Hollow shaft, 10... External shaft coupling,
11... Bow side inner shaft bearing, 12... Bow side outer shaft bearing, 13... Stern side outer shaft bearing, 14... Stern side inner shaft bearing, 15... Rop guard, 16... Hull, 1
7... Rear bulkhead, 18... Oil guide hole, 19... Oil supply hole, 20... Oil drain hole, 21... Lubricating oil outlet pipe, 1
1-2...Drain hole, 30...Fluid restriction element, 14
-1... Bearing metal of the stern inner shaft bearing, 14-2
~14-5...Oil drain hole.

Claims (1)

[Scope of Claims] 1. An inner shaft core of a counter-rotating propeller shaft system, comprising an oil guide hole extending in the axial direction, and an oil supply hole communicating from the oil guide hole to the outer peripheral surface of the inner shaft. , in a bearing device in which lubricating oil is supplied from the oil supply hole and the outer shaft is supported on the outer peripheral surface of the inner shaft, the lubricating oil is fitted onto the inner peripheral surface of the outer shaft corresponding to the opening position of the oil supply hole, and the inner peripheral surface thereof An inner shaft bearing with bearing metal stretched on the side, an oil drain hole provided on the outer peripheral surface of the inner shaft bearing or the inner peripheral surface of the outer shaft, and an orifice for adjusting the amount of oil supply, or an orifice with the same function as this. The fluid restriction element is l/d of the oil supply hole.
>25, where l is the distance from the set position of the fluid restriction element to the outer peripheral surface of the inner shaft, and d is the diameter of the flow path provided in the fluid restriction element. Propeller shaft bearing device.