JP2012148769A - Method for mounting water jet propulsion device on hull - Google Patents

Abstract

PROBLEM TO BE SOLVED: To remedy difficulty of the boring work of a supporting surface of a stern flange in a conventional water jet type ship.SOLUTION: Errors in inclination of a mounting face of a stern flange fixed to a stern part of a ship mounted on a building berth with respect to the axis of a drive shaft are measured. The thickness of material of a flange 81 of a transom short pipe 80 to be joined with the stern flange includes the total value of the designed thickness and the thickness for the errors in inclination. The flange of the transom short pipe is subjected to the machining of cutting to the inclination matched with the errors of inclination in a machining shop different from the building berth. The machined transom short pipe is mounted on the stern flange of the ship on the building berth, and assembled thereto. The mounting face of the flange of the transom short pipe is machined in the machining shop, consequently the mounting face is efficiently machined with excellent accuracy.

Description

  The present invention relates to a method for attaching a water jet propulsion device to a hull of a water jet propulsion type ship.

In a ship provided with a water jet propulsion device at the stern part of the hull, for example, a water jet type aluminum ship, an engine is disposed behind or in the center of the hull, and the impeller constituting the stern propulsion device from this engine In the meantime, a method of driving using a drive shaft is employed.

For example, in a water jet propulsion ship, the distance between the main engine provided at the center of the hull and the impeller provided in the water conduit arranged at the stern of the hull is long, and the rotation speed of the main engine is too high. Since this is not compatible with the rotation of the impeller, a bearing and a speed reducer are provided between the main engine and the impeller, these devices are connected by a first power transmission shaft, and between the speed reducer and the impeller. A device that is connected by a second power transmission shaft, prevents bending of the first power transmission shaft by the bearing, and has the second power transmission shaft thicker than the first power transmission shaft in accordance with the transmission torque. It has been proposed (Patent Document 1).

  Moreover, the structure which connects the hull transom of a water jet propulsion ship and a transom flange with a volt | bolt is proposed (patent document 2).

JP 2003-146291 A JP 2003-112690 A

  The invention described in Patent Document 1 proposes a structure for preventing the deflection of the first power transmission shaft by disposing a bearing and a speed reducer between a main engine and an impeller in a water jet propulsion ship. Means for aligning a series of shaft centers of the first power transmission shaft from the main engine to the speed reducer via the bearing and the second power transmission shaft connecting the speed reducer and the impeller of the pump device. Is not taught at all.

  Patent Document 2 describes a mounting structure between a hull transom and a transom flange. In the invention described in this patent document, a method for mounting a transom flange by processing a flange surface of a hull transom is disclosed. It has only been done. Therefore, in this processing method, a special cutting device must be prepared and processed, and the construction cost of the water jet propulsion ship must be expensive.

   FIG. 2 shows the main part of a water jet type aluminum ship. The suction port 3a of the water guide pipe 3 is opened toward the front of the bottom of the hull 1, and the impeller 4 and the nozzle 5 of the pump device are provided at the rear part thereof. Further, the steering device 6 is arranged at the rear part thereof. The impeller 4 and the engine 2 are connected by a drive shaft 7.

  As shown in FIG. 4, the impeller casing 9 is arranged so that the shaft core (line of sight L) of the transom short pipe 8 attached to the stern end 1 a is aligned with the impeller casing 9 while being accommodated in the impeller casing 9. Inserted and fixed.

   FIG. 3 shows a state in which the transom short pipe 8 is fixed to the stern flange 11 provided at the stern end 1a and the rear end portion of the water guide pipe 3 and the cylindrical portion of the transom short pipe 8 are connected by a flange. . As shown in FIG. 4, the transom short pipe 8 is integrally formed with a water jet propulsion device 10 including a steering device 6, a nozzle 5, an impeller casing 9 for housing the impeller 4, and the like. The impeller casing 9 is fitted and fixed to the pipe 8.

   As shown in FIGS. 2 and 4, the impeller 4 is accommodated in the impeller casing 9, and a slight gap is formed between the tip of the blade and the inner peripheral surface of the impeller casing 9. Although this gap differs depending on the model and size, generally, if the mounting angle of the transom short tube deviates by “± 0.1 to 0.15 degrees” with respect to the shaft center, the impeller 4 and the impeller casing 9 come into contact with each other, resulting in large vibrations. There is a problem that a predetermined pump performance cannot be exhibited.

  Therefore, as shown in FIG. 4, the impeller 4 is mounted so that the rotational surface of the impeller 4 is orthogonal to the drive shaft 7, and the surface of the flange 9a of the impeller casing 9 and the surface of the flange 8a of the transom short tube 8 are parallel. Face to face and need to be fixed accurately.

However, in reality, there is an eccentricity error in the positional relationship between the inner surface of the impeller casing 9 and the impeller 4, and it is often impossible to assemble correctly. Therefore, normally, as shown in FIG. 5, the “gradient” of the mounting surface 11a of the stern flange 11 fixed directly to the stern end 1a (the mounting surface 11a with respect to the disk-shaped surface perpendicular to the axis of the drive shaft ). In order to adjust (tilt state), an inclination adjustment allowance “A” is provided.

  When the stern flange 11 is fixed to the stern end 1a, it is necessary to adjust the mounting surface 11a by boring the error of the stern flange 11 within the range of the inclination adjustment margin A.

  However, in order to accurately drill the inclination of the mounting surface 11a of the stern flange 11 fixed to the stern end 1a, the position measured over the entire circumference of the rear part of the stern flange 11 in the preparation stage corresponds to the position. It is necessary to use a special boring device capable of cutting the surface standing in the vertical direction based on the data after measuring the inclination and the like, and to perform the cutting process for a considerable time.

  Therefore, for example, when the stern flange 11 having a diameter of about 1 m is processed on site, there is a problem that it requires a cost of at least 5 million yen or more and working time.

  An object of the present invention is to solve the problem of requiring a great deal of time and cost for adjusting the mounting surface of the stern flange in the prior art.

  The present invention for solving the above-described problems is configured as follows.

An opening that connects the suction port of the water conduit is formed at the bottom of the hull mounted on the stern, a stern flange is provided at the stern of the hull, and a transom short pipe is fixed to the stern flange.
A suction shaft of the water conduit is connected to the opening, a rear end of the water conduit is fixed to a cylindrical portion of the transom short tube, and a drive shaft connected to a drive device such as an engine provided in the hull is provided. In the construction process of a water jet type ship that extends into the transom short pipe and has an impeller fixed to the drive shaft,
A measurement step of measuring a tilt error of the mounting surface of the stern flange with respect to the axis of the drive shaft;
A preparatory step for forming the thickness of the rough material of the flange forming the transom short pipe composed of a flange and a tube portion joined to the stern flange so as to include the total thickness of the design thickness and the gradient error. ,
A machining step of cutting the mounting surface of the flange of the rough material of the transom short pipe into a gradient according to the gradient error in a factory different from the stern,
An assembly step of assembling the machined transom short tube to a mounting surface of the stern flange on the stern.

In the present invention, an error that the mounting surface of the stern flange fixed to the stern portion of the hull has with respect to a surface orthogonal to the axis of the drive shaft, that is, a “gradient error” is measured.

Then, in a machine factory different from the stern, the mounting surface to be joined to the stern flange of the flange material of the short transom pipe is accurately cut by a cutting device so as to match the inclination error of the stern flange.

As is well known, machinery factories are equipped with large-scale cutting equipment, cranes and other cargo handling facilities and transport facilities, and even large ones such as transom short tubes can be easily transferred, fixed in place, and cut. be able to.

In order to apply the present invention, it is necessary to cut the flange rough material of the transom short pipe in accordance with the inclination error. Therefore, it is formed into a flange having a thickness added with the inclination error of the mounting surface of the stern flange. It is necessary to keep.

  The present invention cuts the mounting surface of the flange of the transom short pipe in response to the inclination error of the stern blunt of the hull mounted on the stern in a machine factory different from the stern. Processing accuracy and cutting work efficiency can be significantly improved.
As a result, the production efficiency can be increased and the manufacturing cost can be greatly reduced as compared with the conventional cutting and assembling method.

As described above, according to the present invention, the assembly work of the hull on the stern and the cutting work in a machine factory different from the stern are performed in cooperation. A highly efficient method for attaching a water jet propulsion device to a hull can be provided.

On the chamfered surface of the stern flange fixed to the stern of the water jet hull, the error relative to the axis (line of sight) of the drive shaft in the circumferential direction ( viewed from the side of the two disk-shaped mounting surfaces and the state that does not match) is generated, in advance of the gradient error is measured, different factories and gridiron by using the adjustment amount of the transom short pipes in view of the gradient errors, in particular the gradient in machine shops Since the error is corrected, the processing can be performed accurately and easily, so that the water jet propulsion device can be attached to the stern portion at a low cost.

  FIG. 1 is a side view of a transom short tube 80 according to an embodiment of the present invention. A flange 81 of the transom short tube 80 is added with a normal thickness “F” and a transom short tube inclination adjustment allowance “A1”. It is characterized in that it is formed with a thickness “T” or slightly thicker.

In the first machining step, as shown in FIG. 3, the inclination of the mounting surface S of the stern flange 11 fixed to the stern end 1 a of the hull 1 with respect to the axis (line of sight L) is determined by the stern flange 11. The measurement is performed over the entire circumference, and the measured position and the error (error with respect to the line of sight L) at the location are measured to measure the “gradient error”. In addition, although the method using a laser beam is suitable for the measurement of the said line of sight L (measurement of an axial center), it is also possible to measure using a piano wire.

In the next step, the mounting surface S of the stern flange 11 fixed to the hull is used as a reference so as to cancel the “gradient error” using a milling machine or the like as the cutting equipment in a factory different from the stern. Based on the measured data (gradient error), the slope adjustment margin “A1” of the flange 81 of the transom short tube 80 is cut.

  As described above, when the portion of the inclination adjustment allowance “A1” shown in FIG. 1 is cut by the mechanical equipment in the factory, the center line L1 of the transom short tube 80 becomes a proper place (the center of FIGS. 3 and 4). Corresponding to the line L).

  Therefore, by attaching the transom short tube 80 whose inclination is adjusted as described above to the portion of the stern flange 11 depicted in FIG. 3, the center line L of the stern flange 11 and the center line of the transom short tube 80 are adjusted. L1 (FIG. 1) matches.

  In this state, as described above, the impeller casing 9 and the impeller 4 inside the impeller casing 9 are concentrically held, and the rotation surface at the tip of the impeller and the inner surface of the impeller casing 9 are A water jet propulsion device that can keep the gap constant and keep the pump performance to the maximum can be installed on the stern.

In the present invention, the mounting surface of the flange 81 of the transom short pipe 80 (inclination adjustment allowance 82 of the transom short pipe 80) is cut in a factory different from the stern to match the axis of the drive shaft 7 to shorten the transom short. It becomes possible to match the axis of the tube 80.

  Therefore, in the conventional process, a process with difficulty in cutting the mounting surface 11a of the stern flange 11 (FIGS. 3 and 5) fixed in an upright state is required. Since the transom short tube 80 (coarse material), which is a product, can be handled as a single unit, the axis can be accurately aligned using a normal machine tool in the factory. Can be completed very easily and at a low cost (about one-tenth of the conventional one).

It is a side view of the transom short tube concerning the present invention. It is a schematic sectional drawing of the stern part of the aluminum ship equipped with the water jet propulsion apparatus. It is sectional drawing which shows a stern part structure. It is explanatory drawing which shows the state which fixes a water jet propulsion apparatus to a stern part. It is sectional drawing which shows the conventional stern flange and a transom short pipe.

DESCRIPTION OF SYMBOLS 1 Hull 1a Stern end 3 Water conduit 3a Water inlet 4 Impeller 5 Nozzle 6 Steering device 7 Drive shaft 8 Conventional transom short tube 9 Impeller casing 10 Water jet propulsion device 11 Stern flange 11a Mounting surface 80 Transom short tube (of the present invention)
81 Flange 82 Transom short pipe inclination adjustment allowance

Claims (1)

An opening that connects the suction port of the water conduit is formed at the bottom of the hull mounted on the stern, a stern flange is provided at the stern of the hull, and a transom short pipe is fixed to the stern flange.
A suction shaft of the water conduit is connected to the opening, a rear end of the water conduit is fixed to a cylindrical portion of the transom short tube, and a drive shaft connected to a drive device such as an engine provided in the hull is provided. In the construction process of a water jet type ship that extends into the transom short pipe and has an impeller fixed to the drive shaft,
A measurement step of measuring a tilt error of the mounting surface of the stern flange with respect to the axis of the drive shaft;
Preparatory step for forming the thickness of the rough material of the flange forming the transom short pipe composed of a flange and a cylindrical portion joined to the stern flange so as to include the total thickness of the design thickness and the gradient error When,
A machining step of cutting the mounting surface of the flange of the rough material of the transom short pipe into a gradient according to the gradient error in a factory different from the stern,
A method of attaching a water jet propulsion device to a hull, comprising assembling the machined transom short tube to a mounting surface of a stern flange of a hull on the stern.

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