RU2248546C2 - Method of balancing propeller - Google Patents

Abstract

FIELD: shipbuilding and ship-repairing; balancing the fixed-pitch propellers.

SUBSTANCE: according to results of measurements of static moments of mass of blades, mass and coordinates of balancing weight are calculated; balancing weight is secured over periphery of inner surface of propeller fairing or over periphery of end surface of hub under fairing.

EFFECT: enhanced efficiency of balancing process; improved hydrodynamics of fixed-pitch propeller.

3 cl, 2 dwg

Description

The invention relates to the field of shipbuilding and ship repair and can be used for balancing propellers with a fixed pitch.

There is a known method of balancing a propeller, in which the propeller blades are balanced separately on a special balancing stand, then the propeller is assembled on a mandrel, mounted on the knives of the balancing stand and static balancing of the propeller is carried out with measured balancing weights with the subsequent determination of places on the hub and on the surfaces of “heavy ”Blades from which the metal will be removed (1).

A disadvantage of the known balancing method is the need for multiple removal and installation of the propeller on the mandrel of the balancing stand and on the processing machine to remove the unbalance, which leads to a decrease in productivity and increase the complexity of the balancing process.

The closest adopted for the prototype is the method of balancing the propeller, in which the assembled propeller is installed on the device for static balancing and determine the static mass moment of the assembled propeller with the horizontal position of one of the blades. Dividing the result by the mass of the blade, determine the amount of displacement of this blade along its axis. The measurement is repeated for all blades (2).

The disadvantage of this balancing method is the need for preliminary assembly, disassembly of all propeller blades to adjust the displacement of each blade along their axes, which leads to an increase in the complexity of the balancing process and to a deterioration in the hydrodynamic characteristics of the balanced propeller, since the displacement of the blades leads to their radial runout from due to changes in the propeller geometry.

The problem solved by the claimed invention is the development of a method of balancing a propeller with a fixed pitch, superior to the known method of balancing in terms of performance, labor and hydrodynamic characteristics of a balanced propeller.

The essence of the claimed invention is that they determine the location and mass of the balancing load (mr) and attach it to the propeller, characterized in that it determines:

- the maximum allowable static moment (M1) at which the blade is balanced relative to the axis of rotation of the propeller,

- the value of the static moment (M1h) relative to the axis of rotation of the propeller,

- the maximum allowable static moment (M2) at which the blade is balanced relative to the centerline of the blade,

- the value of the static moment (M2h), relative to the axial line of the blade, and then determine the total deviation of the moment of each blade:

, где

where

Δ ₁ = M1-M1h,

Δ ₂ = M2-M2h,

choose the radius of the periphery of the inner surface of the propeller (Rr), determine the mass of the load

determine the angle of the balancing load according to the following relationship:

- расстояние от оси гребного винта до центра тяжести лопасти,

- the distance from the axis of the propeller to the center of gravity of the blade,

- расстояние от осевой линии лопасти до центра тяжести лопасти,Where

- the distance from the centerline of the blade to the center of gravity of the blade,

m is the mass of the blade,

after which a balancing load is fixed along the standard load on the periphery of the internal cavity of the propeller, for example, on the periphery of the end surface of the hub under the fairing or on the inner surface of the fairing.

The proposed method of balancing the propeller is new: the difference from the prototype is the calculation of the mass of the balancing load, determining its location on the basis of measurements of the static moments of the individual blades without balancing the propeller assembly and securing the load nominally on the periphery of the internal cavity of the propeller gives a positive effect and has an inventive step , since the set of essential features of the invention leads to a new technical result - to increase the productivity of the process of balancing ki, reducing the complexity of balancing and improving the hydrodynamic characteristics of a balanced propeller.

The invention is illustrated by the drawing, in which Fig. 1 shows a propeller in section, which shows a balancing load 1, mounted on the periphery of the end surface of the hub 2 under the fairing 3.

Figure 2 shows a propeller in section, which shows a balancing load 1, mounted on the periphery of the inner surface of the fairing 3.

The proposed method is as follows.

Static balancing of the propeller blades is carried out according to the values of the static moment indicated in the drawing relative to the axis of rotation of the propeller equal to M1h ± δ, and the static moment relative to the axial line of the blade equal to M2h ± δ, where δ is the tolerance on the values of static moments established by the OST5 standard. 4200.

The static moments M1 and M2 are measured separately for all blades, where M1 is the maximum permissible static moment at which the blade is balanced relative to the axis of rotation of the propeller and is equal to: M1 = M1h + δ, where M2 is the maximum permissible static moment at which the blade is balanced relative to the centerline of the blade, and is equal to: M2 = M2h + δ.

If the blade tolerances are exceeded for moment M1 by δ + ε1 and moment M2 by δ + ε2, where

ε1 - the excess of the permissible moment M1,

ε2 - the excess of the permissible moment M2,

To comply with the conditions of balance, the mass of the balancing load and its location at the end of the hub located under the cowl are calculated as follows:

Δ ₁ = M1-M1h - for moment M1 (relative to the axis of rotation of the propeller),

Δ ₂ = M2-M2h - for the moment M2 (relative to the axial line of the blade).

The total deviation of the moment of each blade is determined:

Structurally, the radius of the periphery of the inner surface of the propeller Rr is selected.

Calculate the mass of the cargo:

Calculate the angle of the balancing load according to the formula:

где

Where

- расстояние от оси гребного винта до центра тяжести лопасти,

- the distance from the axis of the propeller to the center of gravity of the blade,

- расстояние от осевой линии лопасти до центра тяжести лопасти,

- the distance from the centerline of the blade to the center of gravity of the blade,

m is the mass of the blade. Set the balancing load nominally in the estimated location.

Checking the static balance of the propeller by installing a test load on the blade end edge showed that the balanced propeller complies with GOST8054-81 (ISО484-81).

Thus, the proposed method improves the performance of the balancing process and improves the hydrodynamic characteristics of the propeller with a fixed pitch.

Sources of information

1. Balancing propellers. S. M. Gorokhovsky, "Shipbuilding", 1964, pp. 35-44.

2. USSR author's certificate No. 1456796, cl. G 01 M 1/12, 1989 (prototype).

Claims (3)

1. The method of balancing the propeller, which consists in determining the location and mass of the balancing load (mg) and attaching it to the propeller, characterized in that they determine for each blade the maximum allowable static moment (M1) at which the blade is balanced relative to the axis of rotation of the propeller, the value of the static moment (M1h) relative to the axis of rotation of the propeller, the maximum permissible static moment (M2), at which the blade is balanced relative to the center line blade static moment value (m2h) relative to the axial line of the blade, and then determine the total time the deviation of each blade from the following relationship:

, where Δ ₁ = M1-M1h and Δ ₂ = M2-M2h, choose the radius of the periphery of the inner surface of the propeller (Rg), determine the mass of the load (mg) and the angle of the balancing load (α) from the following ratios:

Where

- the distance from the axis of the propeller to the center of gravity of the blade,

- the distance from the centerline of the blade to the center of gravity of the blade, m is the mass of the blade, after which a balancing load is fixed in a regular manner on the periphery of the internal cavity of the propeller. 2. The method according to claim 1, characterized in that the balancing load is fixed on the inner surface of the propeller fairing. 3. The method according to claim 1, characterized in that the balancing load is fixed on the periphery of the end surface of the hub under the propeller fairing.

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