JP5171599B2 - Evaluation method for shaft alignment in ships - Google Patents

Description

  The present invention relates to an evaluation method capable of easily evaluating axis system alignment, for example, when building a ship.

Conventionally, when determining a shaft alignment in a ship, from experience, a certain alignment is predicted, a bearing height is set based on the predicted value, and a bearing load and a crank differential are measured with respect to the set value. At the same time, it is determined whether or not these measured values are within an allowable value, and when the measured value is not within the allowable value, adjustment is made so that the measured value is within the allowable value (for example, Patent Document 1). reference). As for the hull design, naturally, deformation of the hull is considered, but the engine portion is not taken into consideration.
JP2003-19997

  As described above, conventionally, when building a ship, the bearing height of the engine and the intermediate bearing height are determined by prediction based on experience. However, when building a ship, it is desirable to easily and quickly determine whether the bearing alignment is good or bad, that is, the deformation of the hull and the engine part. Yes.

  Accordingly, an object of the present invention is to provide a shaft alignment evaluation method in a ship that can easily and quickly evaluate a shaft alignment in consideration of an engine portion in addition to a hull deformation at the time of construction of a ship. To do.

In order to solve the above-described problem, a shaft system alignment evaluation method for a ship according to claim 1 of the present invention is a shaft system comprising an engine crankshaft and an intermediate shaft disposed between the crankshaft and the propeller shaft. An alignment evaluation method,
Considering a two-dimensional plane in which the coordinate axis is the engine bearing height that is the height of the engine bearing that supports the crankshaft and the intermediate bearing height that is the height of the intermediate bearing that supports the intermediate shaft,
Dividing at least the maximum possible deflection amount at the crankshaft and at least the maximum possible deflection amount at the intermediate shaft at a predetermined interval, and obtaining a plurality of data sets each having both of these divided deflection values as a set,
The deflection values of these data sets obtained are the engine bearing height at the stern end on the crankshaft and the intermediate shaft bearing height on the intermediate shaft,
Next, when the stern tube supporting the propeller shaft is horizontal and the installation state of the engine is parallel to the stern tube, based on the state quantities obtained using the transfer matrix method for each of the above data sets. The data set of the engine bearing height and the intermediate bearing height that can satisfy the predetermined constraints is obtained for each of the above constraints,
Next, the entire solution that satisfies all the individual solutions as the data set obtained for each of these constraints is represented on a two-dimensional plane in a graph.
Next, for each data set of engine bearing height and intermediate bearing height satisfying the above overall solution in this graph, each of the above when the hull deformation according to the draft of the hull is given at a predetermined deformation interval. This is a method of evaluating the axis system alignment by displaying the allowable deformation amount satisfying the constraint condition on the graph.

  A shaft system alignment evaluation method for a ship according to claim 2 is a method in which the hull deformation is given by inclining the engine at a predetermined angle in the shaft system alignment evaluation method according to claim 1.

  A shaft system alignment evaluation method for a ship according to claim 3 is the shaft system alignment evaluation method according to claim 1, wherein the hull deformation is based on a hull deflection curve obtained by theoretical calculation or by an existing hull. It is a way to give.

  Furthermore, the shaft system alignment evaluation method for a ship according to claim 4 is the shaft system alignment evaluation method according to any one of claims 1 to 3, wherein the constraint conditions are bearing load, bearing surface pressure, and propeller shaft deflection. The allowable values for the bending stress of the shaft, the bending moment of the shaft, and the crank differential are used.

  According to the shaft alignment evaluation method described above, the engine bearing height that can satisfy the predetermined constraints when the stern tube that supports the propeller shaft is horizontal and the installation state of the engine is parallel to the stern tube, and A data set of intermediate bearing height is obtained for each of the above constraints, and then an overall solution that satisfies all of the conditional solutions as the data set obtained for each of these constraints is obtained, and this overall solution is calculated as the engine bearing height. The height and the intermediate bearing height are each represented as a graph on a two-dimensional plane with coordinate axes, and then the hull deformation corresponding to the draft of the hull is a predetermined deformation for the entire solution represented by this graph. Since the allowable deformation amount of the hull when given at intervals is obtained for each of the deformation intervals and divided on the graph, using this graph, for example, engine bearing height and medium Compared to the case where the allowable deformation amount when the hull deformation is applied is obtained for all data sets that can be assumed as the bearing height, the allowable deformation amount of the hull can be obtained. It can be done easily and quickly.

[Embodiment 1]
Hereinafter, an axis system alignment evaluation method for a ship according to Embodiment 1 of the present invention will be described with reference to the drawings.

  This shaft alignment evaluation method is an alignment evaluation method for a shaft system including an engine crankshaft, an intermediate shaft, and a propeller shaft in a ship such as a large bulk carrier or a content ship.

By the way, before explaining this alignment evaluation method, a method for calculating the state quantity of the shaft system used in the evaluation method will be described.
First, a transmission matrix method for obtaining state quantities such as displacement and acting force in the shaft system based on the basic structure of the hull, the engine bearing height, and the intermediate bearing height will be described. The engine bearing height refers to the height of the engine bearing that supports the crankshaft of the engine, and the intermediate bearing height refers to the height of the intermediate bearing that supports the intermediate shaft.
(1) First, the hull structure will be briefly described with reference to FIG.

  Usually, the ship bottom portion of a large vessel has a double bottom structure. As shown in FIG. 1, an engine (engine) 1 is disposed on the double bottom portion, and an intermediate shaft is provided toward the stern side. 3 and the propeller shaft 4 are arranged, and the crankshaft 2, the intermediate shaft 3 and the propeller shaft 4 of the engine 1 constitute a shaft system.

Here, the arrangement of bearings in this shaft system will be described.
In addition, the engine 1 demonstrates what rotates the crankshaft 2 with seven pistons, for example.

  That is, for the crankshaft 2 of the engine 1, eight bearings 5A are provided, but the rear end portion of the stern side is further supported by the bearing 5A provided in the partition wall, and the intermediate shaft 3 Is supported by a bearing 5B provided at an intermediate position thereof, and the propeller shaft 4 is supported by two stern tube bearings, that is, a stern tube bearing 5C on the bow side and a stern tube bearing 5D on the stern side. ing. The crankshaft 2 is supported by # 1 to # 8 bearings arranged in the engine itself, but its stern side end is also supported by a # 9 bearing provided in the partition wall.

Therefore, in this shaft system, # 1 to # 9 bearings 5A arranged at nine locations on the crankshaft 2, # 10 bearings 5B arranged at one location on the intermediate shaft 3, and 2 for the propeller shaft 4. The bearings 5C and 5D of # 11 to # 12 arranged at the locations are provided. For the bearing 5A of the crankshaft 2, # 1 indicates the fore side (Fore) and # 9 indicates the stern side (Aft). Of course, a crankpin 13 is provided at a position corresponding to each piston 11 of the crankshaft 2 via a crank arm 12, and the crankpin 13 and the piston 11 are connected to each other via a connecting rod 14. .
(2) Next, the outline of the transfer matrix method will be described.

Here, a description will be given of a method of obtaining a displacement by a transfer matrix method among state quantities at a predetermined position (hereinafter also referred to as each part) of the crankshaft 2 of the engine 1.
In this transfer matrix method, when calculating the displacement of each part over the entire crankshaft 2, a case transfer equation (the coefficient is called a case transfer matrix) is used to transmit the displacement in a straight portion such as a beam. In addition, a gradual point transfer equation (the coefficient is called a grading point transfer matrix) is used to transmit displacement, deflection angle, force and moment at the fulcrum (bearing or axial change point) that breaks the continuity of the beam. The

  In the following description, as shown in FIG. 2, the transmission matrix method is applied along the crankshaft 2, but the direction along the crankshaft (journal axis) is defined as the global coordinate system (x, y, z). And the direction along the crank arm 12 and the crank pin 13 is a local coordinate system (x ′, t, r, also referred to as a relative coordinate system). FIG. 2 shows how to set the global coordinate axis in one crank throw, and FIG. 3 shows the force acting on the crank throw broken down into the local coordinate system.

In the following description, symbols not particularly mentioned are as follows. These values are input from, for example, a data input unit (described later).
a: Initial length between crank arms A: Cross-sectional area D _d : Distance between crank arms Def: Crank differential (abbreviation for crank deflection)
E: Longitudinal elastic modulus F: Shear force G: Shear coefficient I: Cross section secondary moment J: Cross section secondary pole moment k: Bearing spring constant L: Length M: Bending moment T: Torsion moment θ: Crank angle As shown in the following equation, an equation is created in which the state quantity (displacement and acting force) B in the bow side bearing is unknown. In the following equation, S is a case transmission matrix, P is a point transmission matrix, R is a boundary matrix representing boundary conditions on the bow side, and R 'is a boundary matrix on the stern side, which are known.

R ′S _ns P _ns−1 S _ns−1 ... P ₁ S ₁ RB = 0
The superscript ns in the above formula represents the number of shafts between the shaft ends of the bow side (Fore) and the stern side (Aft) separated by the bearings between them.

  Then, by solving this equation, the state quantity B on the bow side is obtained. This state quantity B is the displacement vector q and the force vector Q shown in the following description. Hereinafter, with these state quantities as initial values, the case transfer equation and the point transfer equation are repeatedly used, The state quantity at is obtained.

  That is, the displacement vector q and the force vector Q, which are state quantities in the global coordinate system, are expressed by the following equations (1) and (2). In addition, the vector in a type | formula shall be represented by a bold type.

但し、（１）式中、ｄ_ｘ，ｄ_ｙ，ｄ_ｚは変位・撓み等を示し、またφ_ｘ，φ_ｙ，φ_ｚはねじれ角・撓み角等を示し、（２）式中、Ｔ_ｘ，Ｍ_ｙ，Ｍ_ｚはねじりモーメント・曲げモーメント等を示し、またＦ_ｘ，Ｆ_ｙ，Ｆ_ｚは軸力・せん断力等を示す。

However, in equation (1), d _x , _dy , d _z indicate displacement / deflection, etc., and φ _x , φ _y , φ _z indicate torsion angle / deflection angle, etc., and in equation (2), T _{x 1} , M _y , and M _z represent torsional moment, bending moment, and the like, and F _x , F _y , and F _z represent axial force, shearing force, and the like.

  Further, the displacement vector q ′ and the force vector Q ′, which are state quantities in the local coordinate system, are expressed by the following equations (3) and (4).

同様に、（３）式中、ｄ_ｘ′，ｄ_ｔ，ｄ_ｒは変位・撓み等を示し、またφ_ｘ′，φ_ｔ，φ_ｒはねじれ角・撓み角等を示し、（４）式中、Ｔ_ｘ′，Ｍ_ｔ，Ｍ_ｒはねじりモーメント・曲げモーメント等を示し、またＦ_ｘ′，Ｆ_ｔ，Ｆ_ｒは軸力・せん断力等を示す。

Similarly, (3) _{where, d x ', d t,} d r represents the displacement and deflection, etc., also _{φ x', φ t, φ} r represents the twist angle, the deflection angle, etc., (4) T _{x ′} , M _t , and M _r indicate torsional moment, bending moment, and the like, and F _{x ′} , F _t , and F _r indicate axial force, shearing force, and the like.

  Next, a case transfer equation and a case transfer equation used in the transfer matrix method will be described. The distance transfer equation for determining the state quantity from the bow side (fore side, represented by a subscript F) to the stern side (after side, represented by a subscript A) is expressed by the following equation (5). Is done.

  However, in Formula (5), i shows a bearing number (number of the axis | shaft divided by a bearing).

次に、状態量を、グローバル座標系からローカル座標系に変換する座標変換式（伝達方程式）は、下記（６）式にて表される。

Next, a coordinate conversion equation (transfer equation) for converting the state quantity from the global coordinate system to the local coordinate system is expressed by the following equation (6).

一方、状態量を、ローカル座標系からグローバル座標系に変換する座標変換式（伝達方程式）は、下記（７）式にて表される。

On the other hand, a coordinate conversion equation (transfer equation) for converting the state quantity from the local coordinate system to the global coordinate system is expressed by the following equation (7).

例えば、ジャーナル部からクランクアームへの座標変換式（伝達方程式）は、下記（８）式にて表される。

For example, a coordinate conversion equation (transmission equation) from the journal portion to the crank arm is expressed by the following equation (8).

また、クランクアームからジャーナル部への座標変換も、上記（８）式が使用される。

The above equation (8) is also used for coordinate conversion from the crank arm to the journal portion.

  Further, the coordinate conversion formula (transfer equation) from the crank pin to the crank arm is expressed by the following formula (9), and the coordinate conversion from the crank arm to the crank pin is also expressed by the same formula (9) below. .

ところで、各軸受における格点伝達方程式は、下記（１０）式にて表される。

By the way, the rating transmission equation in each bearing is expressed by the following equation (10).

なお、上記ｈ_２におけるｄ_ｚ０に軸受高さデータが代入される。なお、鉛直方向の変位だけを求める場合には、ｄ_ｙ０については「０（ゼロ）」とされる。

Incidentally, the bearing height data to _{d z0} in the _{h 2} is substituted. When only the displacement in the vertical direction is obtained, _dy0 is set to “0 (zero)”.

Next, the crank differential calculation procedure will be described.
Here, d _x1 , d _y1 , and d _z1 are displacements at the bow side of the crank throw, d _x2 , d _y2 , and d _z2 are displacements at the stern side of the crank throw, and a is the crank throw. Assuming the initial length, the distance D _d between adjacent crank throws is expressed by the following equation (11) (however, the subscript 1 for d such as displacement / deflection is shown in FIG. Similarly, the subscript 2 indicates the position (h) in FIG. 4).

また、ピストンの上死点（ＴＤＣ，０度）での距離をＤ_０、ピストンの下死点（ＢＤＣ，１８０度）での距離をＤ_１８０とすると、クランクデフ（Ｄｅｆ）は、下記（１２）式にて表される。

Further, assuming that the distance at the top dead center (TDC, 0 degree) of the piston is D ₀ and the distance at the bottom dead center (BDC, 180 degrees) of the piston is D ₁₈₀ , the crank differential (Def) is expressed as (12 ) Expression.

ところで、ａは５×１０^２ｍｍであり、また個々の変位量（ｄ_ｘ，ｄ_ｙ，ｄ_ｚ）のオーダは１０^−３ｍｍであるため、ａの２乗に対して変位量の２乗は無視できるほど小さくなる。そこで、上記（１１）式は下記（１３）式のように変形することができる。

By the way, a is 5 × 10 ² mm, and the order of each displacement amount (d _x , _dy , d _z ) is 10 ⁻³ mm. Therefore, the square of the displacement amount is squared with respect to the square of a. Becomes small enough to be ignored. Therefore, the above equation (11) can be transformed into the following equation (13).

したがって、クランクデフは、下記（１４）式および（１５）式にて求めることができる。なお、（１４）式は鉛直方向および（１５）式は水平方向を表している。

Therefore, the crank differential can be obtained by the following equations (14) and (15). Note that equation (14) represents the vertical direction and equation (15) represents the horizontal direction.

（１４）式および（１５）式から分かるように、クランクデフは、殆ど、クランク軸心方向での変形量に依存している。

As can be seen from the equations (14) and (15), the crank differential mostly depends on the amount of deformation in the crankshaft direction.

  Here, a specific calculation procedure of the crank differential based on the above calculation formula will be described with reference to FIG. Here, the calculation process for each member will be described in order focusing on one crank throw.

Step A. The bearing transmission equation (5) uses the equation (5).
B process. In the bent part of part (b), the left side of formula (5) in step A is substituted into the right side of the coordinate transformation formula of formula (6), and the left side of formula (6) at that time is replaced by formula (8) Substitute in the right side (journal part) of the coordinate transformation formula.

Step C. In part (c), the left side of equation (8) in step B is substituted into the right side of equation (5).
Step D. In part (d), the left side of equation (5) in step C is substituted into the right side of the coordinate transformation equation of equation (9).

E process. In part (e), the left side of equation (9) in step D is substituted into the right side of equation (5).
F process. In the part (f), the left side of the formula (5) in the E step is set as the left side of the formula (9).

G process. In the part (g), the right side [q′Q′1] T _arm of the formula (9) in the F step is substituted into the formula (5).
H process. In the part (h), the left side of the formula (5) in the G step is the left side of the formula (8), and the [q′Q′1] T _journal on the right side of the formula (8) at that time is expressed by the formula (7) Substitute into the right side of the coordinate transformation formula.

Step I. In part (i), the left side of equation (7) in the H step is substituted into the right side of equation (5).
In addition, transmission from a crank throw 12 to an adjacent crank throw 12 [with the fulcrum shown in (j part) as a boundary) uses the rating transmission equation (10), and equation (5) in the I step This is done by substituting the left side of (2) into the right side of equation (10).

Thus, q and Q (Q = 0), which are state quantities, are transmitted from the bow side to the stern side by each transmission matrix that is a coefficient of the transmission equation, and each displacement is obtained. Of course, in the process of transmission, Q also changes according to f ₁ , f ₂ , h ₁ , and h _{2 in} equations (5) and (10).

Next, the constraint conditions used in the following description, that is, the bearing load, the bearing surface pressure, the deflection of the propeller shaft, the bending moment of the shaft, and the calculation method of the bending stress will be briefly described.
(A) The bearing load F is expressed by the following equation (16).

但し、ｄ_０は基準とする軸受高さからの初期の相対変位量を表す。
（ｂ）軸受面圧は、下記（１７）式で表される。

However, d ₀ represents the initial relative displacement from the bearing height as a reference.
(B) The bearing surface pressure is expressed by the following equation (17).

Bearing surface pressure = Bearing load / Bearing area (17)
(C) deflection of the deflection propeller shaft of the propeller shaft corresponds to the deflection angle phi _y of y-axis direction in the stern tube bearing rear position.
(D) bending moment bending moment axis of the shaft corresponds to the y-axis moment M _y of the shaft portion.
(E) The bending stress σ _{y of the} shaft is expressed by the following equation (18).

σ _y = M _y / Z (18)
Where Z is the section modulus of the shaft.
By the way, the shaft system alignment evaluation method according to the first embodiment will be specifically described. The height of the engine bearing that is the height of the engine bearing that supports the crankshaft and the height of the intermediate bearing that supports the intermediate shaft. Considering a two-dimensional plane with the intermediate bearing height as a coordinate axis, at least a maximum possible deflection amount of the crankshaft and at least a maximum possible deflection amount of the intermediate shaft are divided at predetermined intervals, and both of the divided Obtain multiple data sets with one set of deflection values, and calculate the deflection values of these acquired data sets as the engine bearing height at the stern end of the crankshaft and the intermediate shaft bearing height at the intermediate shaft, then the propeller shaft. when the stern tube which supports there is mounted state of the horizontal and is and organizations have to be parallel to the stern tube, use the transfer matrix method with respect to the respective data sets Based on the state quantity obtained in this way, a data set of engine bearing height and intermediate bearing height that can satisfy the predetermined constraints is obtained for each of the above constraints, and then the data obtained for each of these constraints The entire solution, which is a data set that satisfies all the individual solutions, is represented in a graph on a two-dimensional plane, and then the engine bearing height and intermediate bearing height data set that satisfies the above overall solution in this graph. On the other hand, when the hull deformation according to the draft of the hull is given at a predetermined deformation interval, the allowable deformation amount satisfying each constraint condition is divided and displayed on the graph, thereby displaying the shaft system. The alignment is evaluated.

And in this Embodiment 1, a ship body deformation | transformation is provided by inclining an engine.
The above constraint conditions are allowable values for bearing load, bearing surface pressure, propeller shaft deflection, shaft bending stress, shaft bending moment, and crank differential. When determining the permissible values under the following constraints, the transmission matrix method described above is used to determine the state quantities, i.e., crank differential, bearing load, and other acting forces, and these values are acceptable. It is determined whether it is within the value.
(1) A procedure for obtaining initial axis alignment will be described.

  That is, when the engine is flat, in other words, when the engine is parallel to the stern tube bearing reference line, a data set that satisfies each constraint is obtained for each constraint, and the engine bearing height The height and the intermediate bearing height are each represented as a graph on a two-dimensional plane as coordinate axes.

  The range of the above-mentioned engine bearing height and intermediate bearing height as a variable (parameter) is that the propeller shaft and the intermediate shaft are considered to be installed with the maximum deflection amount of the cantilever beam being less than the maximum deflection amount of the cantilever. Is set to the maximum intermediate bearing height and the maximum engine bearing height, and is between the reference line and the maximum deflection amount (the variable range may be set to a value larger than the maximum deflection amount).

  For example, an axis from the stern tube bearing to the intermediate bearing is considered as the propeller shaft, and the maximum deflection when the cantilever is used at this time is 2.76 mm (however, the shaft diameter is 0.79 m). From this, the range of the variable of the intermediate bearing height is set to 0 to 2.76 × 2 (a range that is twice as wide) = 5.52 mm. Similarly, an axis from the intermediate bearing to the engine stern end bearing is considered as the intermediate axis. The maximum deflection in the case of a cantilever is 8.80 mm (however, the shaft diameter is 0.79 m). Since this maximum deflection is based on the intermediate bearing height, the intermediate bearing height range is added to obtain the engine bearing height from the reference line. Therefore, the range of the variable of the engine bearing height is 0 to 14.32 (5.52 + 8.80) mm.

  FIG. 5 shows an initial data set (data indicating the combination) of the engine bearing height and the intermediate bearing height for determining the shaft system alignment effective range. The horizontal axis is the intermediate bearing height, the vertical axis is the engine bearing height, and the range of the vertical axis and the horizontal axis is divided into 21 parts, for a total of 21 × 21 = 441 engine bearing heights and intermediate bearing heights. This is a combination of the two.

In calculating each bearing height, a predetermined state quantity is obtained by substituting the intermediate bearing height and the engine bearing height with the stern tube, that is, the stern tube bearing as a reference line, into the arithmetic expression in the transmission matrix method described above.
(A) Hereinafter, the constraint conditions will be described.

A1: Bearing load The bearing load is within a predetermined value range (for example, according to engine guidelines or classification guidelines).

A2: Bearing surface pressure The bearing surface pressure P is set to a range between zero and an allowable value (set value). For example, 0 ≦ P ≦ 10 MPa, which is determined from the material or the like.

A3: Deflection of propeller shaft The deflection of the propeller shaft is the deflection at the stern tube rear bearing position, and is in a range between zero and an allowable value (set value). For example, θ ≦ about 3.0 × 10 ⁻⁴ rad.

A4: Bending stress of shaft The bending stress σ of the shaft is set within a range of an allowable value (set value) or less. For example, σ ≦ about 20 N / mm ² (2 kgf / mm ² ).

A5: Shaft Bending Moment The shaft bending moment M _i is in a range equal to or less than the moment of the propeller shaft end. That is, M _i ≦ propeller shaft end moment.

A6: Crank differential The crank differential Def is a predetermined range, that is, a range between the lower limit set value and the upper limit set value. That is, x ≦ Def ≦ y (for example, according to engine guidelines).
(B) Next, for A1 to A6 when the engine is parallel to the reference line, a data set of engine bearing height and intermediate bearing height satisfying the respective allowable values is obtained. Of course, it is performed for all data sets.

The obtained data sets of the two bearing heights, that is, the condition solutions are shown in graphs as shown in FIGS.
6 shows the range of the data set that satisfies the bearing load, FIG. 7 shows the range of the data set that satisfies the deflection angle of the stern tube, and FIG. 8 shows the range of the data set that satisfies the bending stress of the shaft. FIG. 9 shows the range of the data set that satisfies the bending moment of the shaft, and FIG. 10 shows the range of the data set that satisfies the crank differential. In addition, about the bearing surface pressure, since the bearing load is satisfied, the bearing surface pressure is also satisfied. Therefore, the graph is omitted.

When a complete solution, which is a data set that satisfies all the above-described constraints, is obtained, a graph as shown in FIG. 11 is obtained.
The complete solution C is expressed by the following equation (19).

C = ΠB _i (19)
However, B _i (i = 1 to 6) indicates a solution under each constraint condition (A1 to A6).
The complete solution C indicates an effective area for installation, and the area is represented by a matrix (m × n). If this complete solution C is represented on FIG. 5 which shows the data set of both bearing heights, it will become like FIG. In FIG. 12, the blacked out portion indicates the effective range, that is, the complete solution portion (the same applies to FIGS. 13 and 14 shown below).

  According to the above procedure, when the engine is in a horizontal state, that is, when the hull is not deformed, a complete solution that satisfies the above constraints, that is, the range of the data set of the engine bearing height and the intermediate bearing height is obtained. It is represented by a graph.

  In the above-described example and FIG. 12, in the installation of the engine, the result when the engine is parallel to the reference line of the stern tube bearing (that is, when the tilt amount = 0.0 mm / m) is shown. In the case where the engine has a lower bow side than the stern side with respect to the reference line of the stern tube bearing (when the engine is inclined counterclockwise with respect to the stern end bearing of the engine), It is obtained in the same way as the example.

  For example, when the bow end of the engine is installed 2 mm vertically below the horizontal plane [that is, when the tilt amount = 0.2 mm / m: the tilt amount is located at the bow end of the engine per engine length. The result is a vertical downward displacement of the bearing, where the engine length is 10 m, and thus the vertical downward displacement is 2 mm (= 0.2 mm / m × 10 m)] 13 and so on. The engine bearing height in FIG. 13 represents the height from the line to the bearing located at the stern end of the engine when the stern tube bearing is a line of sight. Therefore, the bearing height located at the bow end of the engine is a value obtained by adding 0.2 mm of the engine tilt amount vertically downward to the bearing height located at the stern end.

  Similarly, when the bow end of the engine is installed 4 mm vertically below the horizontal plane [that is, when the tilt amount is 0.4 mm / m: the tilt amount is at the bow end of the engine per engine length. The result is a vertical downward displacement of the bearing that is located, where the engine length is 10 m, and thus the vertical downward displacement is 4 mm (= 0.4 mm / m × 10 m)]. As shown in FIG.

  In this way, it is possible to determine the allowable range of the initial bearing alignment in consideration of the initial engine inclination. Therefore, in this method, the allowable range of the shaft system alignment, that is, the design range, can be determined by using three parameters of the engine inclination, the bearing height at the stern end of the engine, and the intermediate bearing height as parameters.

  Next, with respect to the data set of the engine bearing height and the intermediate bearing height according to the complete solution, an allowable deformation amount when the hull is further deformed according to the draft is obtained. That is, in the graph showing the complete solution, the allowable deformation amount in the data set of the engine bearing height and the intermediate bearing height that satisfies the respective constraints when the hull is deformed is shown on the graph.

When applying the hull deformation, as shown in FIG. 15, the engine is given an inclination angle θ _e such that the bow end side is lower than the stern end side.
Hereinafter, a specific procedure for obtaining the allowable deformation amount will be described.

That is, in the complete solution range, when the engine is tilted in a counterclockwise direction by a predetermined angle (θ _e : θ _e ≧ 0), the tilt angle θ _e that satisfies each constraint condition (shaft system alignment) is obtained.
In this case, a plurality of boundary values of an effective range (also an effective area at the filled portion) on the graph shown in FIG. 12, for example, four corner points U1 to U4 and intermediate points V1 to V4 on a line connecting the respective points are represented. against 8 points including (that is, the representative points), with a tower predetermined intervals given inclination angle theta _e, and determines whether or not satisfy each constraint condition.

Here, a procedure (calculation step) for obtaining an allowable deformation amount for each data set when the engine is inclined will be described.
First, it sets as follows the range of the inclination angle theta _e of the engine.

For theta _e, in the range of _{^{0.5 × 10 -7 × L 3 /}} L e ~2.0 × 10 -7 × L 3 / L e. The reason for this range is that between the length L of the shaft system in the hull and the maximum deflection ν _max , approximately 0.5 × 10 ⁻⁷ × L ^{3 to} 2.0 × 10 ⁻⁷ × relationship of L ^3. In the present embodiment, there is a relationship of 1.67 × 10 ⁻⁷ × L ³ .

Then, the inclination angle theta _e is moderate step width [Delta] [theta] _e, for example given by θ _e / 10~θ _e / 5 width, here, and θ _e / 5 (5 is equal parts).
Therefore, Δθ _e = θ _e (i) = i × Δθ _e
(However, i = 1,..., N (= 5))
Each bearing height in the engine with respect to the inclination of the engine is expressed by the following equation (20).

H _e (j) = H _ea + {L _e −x _e (j) × tan θ _e (i)} (20)
H _ea : Bearing height located at the stern end of the engine x _e (j): Distance from the bearing located at the bow end of the engine to the j-th main bearing And the engine is inclined with respect to each of the above representative points The remaining bearing heights other than the end bearings in the engine are determined by the above equation (20), the intermediate bearing height that is the representative point, the stern end bearing height of the engine at the representative point, and the above equation (20). Using the remaining bearing heights in the engine determined by (1), an individual solution as a data set that satisfies each constraint condition is obtained, and a complete solution as a data solution that satisfies all individual solutions is obtained. What is necessary is just to obtain the maximum inclination angle θe as the allowable deformation amount related to the solution.

  Thus, the allowable engine inclination angles (allowable deformation amounts) for each representative point are obtained, and these allowable inclination angles are graphed with the engine bearing height and intermediate bearing height as variables (two-dimensional coordinate axes). Is represented as shown in FIG. However, in FIG. 16, the negative value increases toward the upper side and the right side (the negative value increases toward the upper side and the right side) as opposed to the numerical values of the coordinate axes in FIGS. ).

From the graph of FIG. 16, it can be seen that the lower the engine bearing height is compared to the intermediate bearing height, the greater the alignment of the hull deformation.
In the above description, the number of representative points is eight, but a graph showing a more accurate allowable range can be obtained by increasing the number of representative points.

That is, according to the graph shown in FIG. 16, the engine bearing height and the intermediate bearing height are represented by a two-dimensional plane having coordinate axes, respectively, and the graph represents the allowable tilt angle of the engine (allowable deformation amount of the hull) for the data set. Because the graph is displayed separately for each allowable tilt angle range of the engine, by using this graph, for example, for all possible data sets of the engine bearing height and the intermediate bearing height, the hull deformation Compared with the case where the allowable deformation amount is obtained in the case where the value is given, the allowable deformation amount of the hull can be obtained, and therefore the evaluation of the axial alignment can be performed easily and quickly.
[Embodiment 2]
Next, an axis system alignment evaluation method according to Embodiment 2 of the present invention will be described with reference to the drawings.

  In the first embodiment described above, it has been described that the hull deformation is imparted by inclining the engine. However, in the second embodiment, the hull deformation is imparted based on the deflection curve of the hull. Is.

Note that the difference from the first embodiment described above is only the method for imparting hull deformation, and the other parts are the same, and therefore only the different parts will be described here.
Hereinafter, a case where hull deformation is applied based on the hull deflection curve will be described.

  In this case, as an example of the case where the engine is inclined, the engine is preliminarily inclined at a height of 0.4 mm / m and the bow side is vertically lowered with respect to the stern side (that is, the inclination amount = 0.4 mm / m). In the case of ()).

  The hull deformation is approximated by the following equations (21) and (22) in the coordinate system shown in FIG. 17A is a schematic diagram showing the engine and the propulsion shaft, FIG. 17B is a curve showing the deflection at the double bottom portion, and FIG. 17C is a curve showing the thermal deformation in the engine.

(1) propeller shaft parts: in _{L h} ≧ x ≧ _{L e;}

（２１）式中、Ｚ_ｈは喫水変化に伴う船体撓み量、ｄは喫水深さの相対変化量、ｘは軸方向の座標系（機関の船首端の軸受を原点に取る）、Ｌ_ｈは軸系の全長、Ｌ_ｍ（＝ａ×Ｌ_ｅ（１≦ａ≦Ｌ_ｈ／２Ｌ_ｅ）は船体撓み量が最大となるｘ軸の座標値を示す。

(21) In the formula, Z _h is the deflection amount hull caused by draft change, d is the relative variation of draft depth, x is (taking the bearing of the bow end of the engine to the origin) axially of the coordinate system, L _h is The total length of the shaft system, L _m (= a × L _e (1 ≦ a ≦ L _h / 2L _e )) indicates the coordinate value of the x axis at which the hull deflection amount is maximum.

(2) Engine length portion: at L _e ≧ x ≧ 0;

（２２）式中、Ｚ_ｅは（２１）式のｘ＝Ｌ_ｅにおける値、Ｌ_ｅはクランク軸の長さを示す。

In the equation (22), Z _e represents a value at x = L _e in the equation (21), and _Le represents the length of the crankshaft.

  Furthermore, in the engine section, thermal expansion accompanying cold to warm conditions is considered.

（２３）式中、Ｚ_ｔは温度変化に伴う変形量、ｈは機関の船体との据付下面からクランク軸中心までの距離、Δｔは機関の冷態から温態までの温度変化、αは線膨張係数を示す。

In the equation (23), Z _t is the amount of deformation accompanying temperature change, h is the distance from the bottom surface of the engine to the hull of the engine to the center of the crankshaft, Δt is the temperature change from cold to warm of the engine, and α is a line Indicates the expansion coefficient.

_{Here, a = 1.15, v / d} = 0.33, v d /d=0.40,v t = 0.1, L e = 10.0, was L h = 26.2.
The allowable value of the hull deflection obtained from the above equation (23) is as shown in the graph of FIG.

  The numerical value described in the point plotted in FIG. 18 represents the allowable deflection value of the hull. FIG. 19 shows a contour diagram of FIG. However, also for the numerical values of the coordinate axes in FIGS. 18 and 19, the negative values increase toward the lower side and the left side as in FIG. 16 (that is, the negative values increase toward the upper side and the right side). As shown.

  From FIG. 18, as in the first embodiment, the installation conditions that allow the hull deformation are the allowable deflection amount (allowable deformation amount) of the hull as the engine bearing height is lower than the intermediate bearing height. Is a large alignment.

  In other words, if the hull deflection of the target ship type is known (obtained by theoretical analysis of the hull structure, for example, FEM analysis or by calculating from the inverse analysis of the axis alignment management data in the case of an actual ship), the axis system Know the limits of hull deflection to alignment. Thereby, it becomes possible to obtain the safety factor of the axis alignment with respect to the specifications of the ship.

It is a schematic diagram which shows schematic structure of the shaft system to which the shaft system alignment evaluation method according to Embodiment 1 of the present invention is applied. It is a model front view in 1 crank throw of the crankshaft in a coaxial system. It is a model side view which shows the local coordinate system of the crankshaft. It is a schematic diagram explaining the calculation procedure of the crank differential in the crankshaft. The initial combination data of the intermediate bearing height and the engine bearing height for determining the effective range of the shaft alignment is shown. It is a graph which shows the range of intermediate bearing height and engine bearing height which satisfy the allowable value of bearing load. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy the allowable value of a stern tube deflection angle. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill the tolerance | permissible_range of the bending pressure of a shaft. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill the tolerance | permissible value of the bending moment of a shaft. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy the allowable value of a crank differential. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill all the constraint conditions. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill all the constraints in combination data. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill the restrictions when an initial engine inclination (0.2 mm / m) is given. It is a graph which shows the range of the intermediate bearing height and engine bearing height which satisfy | fill the restrictions when an initial engine inclination (0.4 mm / m) is given. It is a figure explaining the inclination-angle of the engine accompanying ship body deformation. It is the graph which divided and displayed the range of the complete solution which satisfy | fills all the restrictions for every inclination angle. It is a figure which shows the bending of the hull which concerns on the determination method of the axial system alignment which concerns on Embodiment 2 of this invention, (a) is a schematic diagram of an axial system, (b) shows the bending curve of the ship bottom in an engine part. (C) shows the deflection curve of the ship bottom based on the thermal deformation in the engine part. It is a graph which shows the allowable deflection value of the hull in the same Embodiment 2. It is a contour figure of the allowable deflection value of the hull in the second embodiment.

Explanation of symbols

1 Engine 2 Crankshaft 3 Intermediate shaft 4 Propeller shaft 5 Bearing

Claims (4)

An evaluation method for an alignment of a shaft system comprising an engine crankshaft and an intermediate shaft disposed between the crankshaft and the propeller shaft,
Considering a two-dimensional plane in which the coordinate axis is the engine bearing height that is the height of the engine bearing that supports the crankshaft and the intermediate bearing height that is the height of the intermediate bearing that supports the intermediate shaft,
Dividing at least the maximum possible deflection amount at the crankshaft and at least the maximum possible deflection amount at the intermediate shaft at a predetermined interval, and obtaining a plurality of data sets each having both of these divided deflection values as a set,
The deflection values of these data sets obtained are the engine bearing height at the stern end on the crankshaft and the intermediate shaft bearing height on the intermediate shaft,
Next, when the stern tube supporting the propeller shaft is horizontal and the installation state of the engine is parallel to the stern tube, based on the state quantities obtained using the transfer matrix method for each of the above data sets. The data set of the engine bearing height and the intermediate bearing height that can satisfy the predetermined constraints is obtained for each of the above constraints,
Next, the entire solution that satisfies all the individual solutions as the data set obtained for each of these constraints is represented on a two-dimensional plane in a graph.
Next, for each data set of engine bearing height and intermediate bearing height satisfying the above overall solution in this graph, each of the above when the hull deformation according to the draft of the hull is given at a predetermined deformation interval. An evaluation method of shaft system alignment in a ship, characterized in that shaft system alignment is evaluated by dividing and displaying an allowable deformation amount satisfying a constraint condition on the graph.   2. The method for evaluating an axial alignment in a ship according to claim 1, wherein the hull deformation is given by inclining the engine at a predetermined angle.   2. The method of evaluating a shaft alignment in a ship according to claim 1, wherein the hull deformation is given based on a hull deflection curve obtained by theoretical calculation or by an existing hull.   The constraint condition is an allowable value for each of bearing load, bearing surface pressure, propeller shaft deflection, shaft bending stress, shaft bending moment, and crank differential. Evaluation method of shaft alignment in the ship described in 1.

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