JPH0321590A - Marine type rudder bearing - Google Patents

Abstract

PURPOSE:To reduce bending moment applied to a rudder by allowing a bearing rod to dangle at the undersurface of a rudder horn removably, accommodating the bottom of this bearing rod within the rudder, and supporting the lower end shaft part by a bearing mounted in the rudder. CONSTITUTION:From the undersurface of a rudder horn 2, a bearing rod 9 is dangled to the center of a rudder head member 4 and fixed removably to the undersurface of rudder horn 2 by the fastening structure using bolts 12, 13, etc. This bearing rod 9 shall be accommodated in a rudder 3, and the bottom of the rod 9 be a shaft 10 which is borne by a rudder bearing 11 fitted in the rudder 3. These shaft 10 and rudder bearing 11 shall be located between the undersurface of rudder horn 2 and the bottom of the rudder 3. This provision of rudder bearing 11 lessens the cantilever part of the rudder 3 to contribute to reduction of the bending moment to a great extent.

Description

[Detailed description of the invention] (b) Industrial application fields Concerning bearings in Mariner type rudders.

e) Prior Art A conventional Mariner type rudder generally consists of a rudder stock bearing at the top of the rudder stock, a neck bearing at the top of the rudder, and a rudder hanging from the hull at the top and front half of the rudder. It is rotatably coupled to the pintle bearing of the horn.

If we compare this state to a single beam, the rudder is a continuous beam with the rudder head bearing, neck bearing, and pintle bearing as fulcrums, and the portion below the pintle is cantilevered.

The rudder in this state has the following problems.

(a) A large bending moment due to the pressure of the rudder below acts on the pintle portion.

Therefore, the structural dimensions required for the strength of this part are abnormally large compared to other parts.

This disturbs the rudder streamline, increases propulsion resistance, and induces cavitation and erosion.

(b) The center of pressure on the rudder is usually below the pintle. Therefore, the bottle bearing load becomes synthetically large. It can even be more than 1.4 times the independent rudder pressure. Therefore, the bearing size becomes thicker, which has the same disadvantages as in (a).

(C) Furthermore, an increase in the bearing load increases the friction torque of the bearing and increases the horsepower of the steering gear required for steering.

(d) One way to alleviate the problems in (a) - (c) is to extend and expand the rudder horn downward.
This K reduces the movable area of the rudder and reduces rudder efficiency.

It also causes trouble in installing the propeller.

(c) Means for solving the problems Because the conventional Mariner type rudder has a pintle in the center of the rudder, it causes the various problems mentioned in item 0).

In order to solve this problem, the present invention eliminates the pintle in the center of the rudder and installs a new rudder bearing below it. That is, (a) The bearing rod (■) is suspended from the lower surface of the rudder horn (2) to the center of the rudder stock (4).

(b) This bearing rod (2) is detachably attached to the bottom surface of the rudder horn (2). There are various ways to do this,
An example is shown in Figure 3.

This is a pair of flanges that connect the lower part of the rudder horn (2) and the upper part of the bearing rod (9) with bolts U, (13).

(e) Provide the rudder (3) with a rudder bearing 01) for the shaft (io).

(0 pair of shafts (i, rudder bearing (I1) is the rudder bone c
2. ) between the lower surface of the rudder (3) and the lower end of the rudder (3), at an appropriate position that takes into consideration the design and manufacturing of the rudder.

(d) Effects of the invention The present invention can exhibit the following effects.

(a) The cantilevered rudder portion below the rudder bearing can be reduced.

This allows the bending moment to be significantly reduced.

Therefore, the problem of locally enlarging the rudder structure does not occur.

ω) By placing the center of pressure of the rudder between the neck bearing and the rudder bearing, the pressure of the rudder is shared as a positive load to the neck bearing, which replaces the pintle [the load on the bearing can be significantly reduced].

Therefore, there is no need to worry about the size of the rudder bearing becoming particularly large.

(C) For the same reason as φ), the bearing torque can be significantly reduced, and the horsepower of the steering gear can be saved.

(d) Since the rudder bearing is included in the rudder, there is no difference in the side shape of the conventional Mariner type rudder.

Therefore, there is no reduction in rudder efficiency.

(e) Since the bearing rod is removable, there is no problem in attaching the propeller.

As described above, according to the present invention, the problems encountered with conventional Mariner type rudders can be largely solved.

Looking at this in an example, when the rudder bearing is placed midway between the lower surface of the rudder horn and the lower end of the rudder, compared to a conventional Mariner type rudder,
The maximum bending moment applied to the rudder was reduced by about 25%, and the load on the rudder bearing, which replaces the pintle, was reduced to about 60%.

[Brief explanation of drawings]

Fig. 1 is a side view of a conventional Mariner type rudder Fig. 2 is a side view of a rudder with a rudder bearing according to the present invention Fig. 3 is a plan view of the combination of a bearing rod and a rudder bone according to the present invention 1 Hull 2 Rudder horn 3 Rudder 4 Rudder stock 5 Pintle 6 Rudder stock bearing 7 Neck bearing 8 Pintle bearing 9 Bearing rod 10 Shaft 11 Rudder bearing 12 Coupling bolt 1 l3 Coupling bolt 2

Claims (1)

[Scope of Claims] In the Mariner type rudder, (a) a bearing rod (9) is suspended from the lower surface of the rudder horn (2) to the center of the rudder stock (4). (b) The bearing rod (9) is removably connected to the lower surface of the rudder horn (2). (c) The bearing rod (9) is included in the rudder (3). (d) The lower end of the bearing rod (9) is connected to the shaft (10) that constitutes the rudder bearing.
). (e) A rudder bearing (11) for the shaft (10) is provided in the rudder (3). (f) The pair of shafts (10) and rudder bearing (11) are located between the lower surface of the rudder horn (2) and the lower end of the rudder (3). A bearing for a Mariner type rudder constructed as described above.