JPH05246385A - Bearing cooling device for water jet propulsion machine - Google Patents

Abstract

PURPOSE:To cool efficiently by disposing an impeller shaft concentrically in an inducer shaft to form double shaft structure, then providing a water box at a bearing part for rotatably supporting these double shafts, and providing the water box with a conduit for drawing out dynamic water from a diffuser so as to supply it as cooling water. CONSTITUTION:A power part A is provided with an intake B for taking in dynamic water, an impeller 8 for applying pressure to the dynamic water to provide it with turning force, an inducer 5, an impeller driving shaft 3 concentrically provided in an inducer shaft 4 for transmitting power to the inducer 5 so as to form double shaft structure, a bearing part C for rotatably supporting these double shafts, and a diffuser 8 for recovering the pressure of the dynamic water from the impeller 8 to deliver it to a discharge part E. The bearing part C is provided with a water box 20 so as to cool the bearing part C effectively with efficiency. The water box 20 has a conduit 18 with a control valve 19 interposed on one side, and this conduit 18 is connected to the diffuser 8.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to an improvement in a bearing cooling device for a water jet propulsion machine that skillfully absorbs the high heat generation that accompanies the higher output of a rotary shaft.

[0002]

2. Description of the Related Art Recent high-speed boats are shifting from screw propulsion systems to water jet propulsion systems, aiming at ultra-high speed running of 40 to 70 knots.
There is one shown in.

Reference numeral A indicates a power unit which constitutes a central part of the water jet propulsion system, and the power unit A comprises a water intake casing 1 and a discharge casing 2 each having a body length. The water intake casing 1 has an intake B for taking in the moving water, which is a drive source, and is also provided with an inducer 5 for applying a preload to the moving water. The inducer 5 is given a rotational force by an inducer shaft 4 having a reduction gear 13, and the inducer shaft 4 has an impeller shaft 3 arranged concentrically with an inducer bearing 12 interposed therein. It is a so-called double shaft structure type.

One side of the double shaft structure type inducer shaft 4 extends by penetrating the water intake casing 1 and is mounted on the bearing portion C by interposing water seal portions 15 and 17 on the way. Has been done. The bearing portion C is provided in the enlarged portion of the inducer shaft 4, and is divided into one for the inducer shaft and one for the impeller shaft, and the oil seals 11 and 16 for the inducer shaft are provided for each shaft. , And impeller shaft oil seals 9 and 14 are mounted. The other side of the inducer shaft 4 extends along the body shaft of the water intake casing 1, and its end is connected to the inducer 5 via the reduction gear 13.

On the other hand, the impeller shaft 3 contained in the inducer shaft 4 extends along the trunk shaft of the discharge casing 2, and a stay vane 7 attached to a water seal 10 is arranged on the way to the diffuser cone portion D. It is connected. The diffuser cone portion D has a bowl ridge line that bulges leftward and rightward with respect to the body axis of the discharge casing 2, and an impeller 6 is attached to the outer periphery of the bowl ridge line to drive the power from the impeller shaft 3. Is transmitted to the moving water to give it rotational energy. Furthermore, a diffuser 8 is arranged on the outer periphery of the bowl ridge line,
The diffuser 8 recovers the pressure of the moving water from the impeller 6 and sends it to the discharge section E. In this way, the power unit A obtains propulsion by utilizing the jet force of the moving water from the discharge unit E, and promotes ultra-high speed of the watercraft.

[0006]

By the way, since this type of device has an extremely high speed, the amount of moving water to be handled is 1000 m ³ / Mi
It is extremely high as n or more, and reactive heat energy such as frictional heat generated from the bearing portion C during the operation of the power unit A also becomes proportionally high. Therefore, it is no problem to rely on natural heat dissipation anymore, and residual heat is no longer acceptable. As a result, the bearing part C is damaged by burnout of the seal.
This may lead to deterioration of the lubricating oil and wear of the sliding parts of the bearing, leading to a serious accident. The present invention has been made in view of the above circumstances, and an object of the present invention is to disclose a bearing cooling device for a water jet propulsion machine, which can cool a bearing portion effectively and efficiently.

[0007]

The present invention has an impeller shaft concentrically arranged in an inducer shaft, and a water box is provided in a bearing portion that pivotally supports these double shafts, and a diffuser is provided in the water box. It is provided with a conduction path for drawing out the moving water from the tank and supplying it as cooling water.

[0008]

According to the above structure, since a part of the moving water from the diffuser always flows as cooling water in the water box of the bearing portion, friction generated during rotation of the double structure shaft mounted on the bearing portion. Even if the reactive heat energy such as heat becomes large, it can be sufficiently cooled.

[0009]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS An embodiment of the present invention will be described below with reference to the drawings.

FIG. 1 is a partially cutaway schematic view of a bearing cooling device for a water jet propulsion device according to the present invention. The same components as those in FIG. 2 are designated by the same reference numerals, and detailed description thereof will be omitted.

In FIG. 1, a power unit generally designated by A has an intake B for taking in the moving water, an impeller 8 for giving a turning force by pressurizing the moving water, an inducer 5, and a double shaft structure. Inducer shaft 4 that transmits power to inducer 5
An impeller shaft 3 for driving an impeller, which is concentrically installed inside the bearing, a bearing portion C that supports these double shafts, and a diffuser 8 that recovers the pressure of moving water from the impeller 8 and sends it to the discharge portion E.
Is equipped with.

In the above conventional structure, however, in the present invention, the bearing portion C is provided with the water box 20, and the bearing portion C is provided.
Is effectively and efficiently cooled. That is, the inducer shaft 4 including the impeller shaft 3 penetrates the water intake casing 1, extends to the bearing portion C, and is rotatably supported. Although it has seals 15 and 17 and oil seals 9, 11, 14 and 16, it produces high reactive heat energy such as frictional heat because of its ultra-high output for many minutes, and only cooling by conventional seals is required. Then, the heat cannot be removed sufficiently.

For this reason, the bearing portion C is provided with a water box 20 so as to surround the entire area thereof. The water box 20 has a conducting path 18 on one side with a control valve 19 interposed, and the conducting path 18 is connected to the diffuser 8. Further, the other side of the water box 20 has a discharge path 21 for sending the cooling water to the outside.

In the cooling system of the power unit A having the above structure, a part of the moving water passing through the diffuser 8 is utilized as cooling water.
That is, the moving water extracted from the diffuser 8 is guided to the water box 20 through the conduction path 18, where the inducer shaft 4 having the double structure is forcibly cooled, and after cooling, the drainage path 21.
Is sent to the outside via.

Therefore, as the cooling water, a part of the moving water which has already been used can be utilized as it is, so that it is possible to effectively utilize the water without requiring a special cooling water supply source for this kind of apparatus. Since the dynamic water of the diffuser 8 is extremely high in pressure, when it is supplied to the water box 20, the pressure may be controlled by the control valve 19.

[0016]

As described above, in the bearing cooling device for a water jet propulsion device according to the present invention, the bearing portion is provided with the water box, and the moving water of the diffuser is partially drawn into the water box to cool the bearing portion. Since it is used for water, forced cooling can be performed with a simple structure, and therefore, even if the reactive heat energy of this type of device increases as the output increases, it can be sufficiently dealt with.

[Brief description of drawings]

FIG. 1 is a partially cutaway schematic view showing an example of a bearing cooling device for a water jet propulsion device according to the present invention.

FIG. 2 is a partially cutaway schematic view showing an embodiment of a bearing cooling device for a conventional water jet propulsion device.

[Explanation of symbols]

 A power part B intake C bearing part 3 impeller shaft 4 inducer shaft 6 impeller 8 diffuser 18 conduction path 20 water jet

Claims (1)

[Claims] 1. An inducer shaft has concentric impeller shafts, and a water box is provided in a bearing portion that pivotally supports these double shafts. The water box draws dynamic water from a diffuser for cooling. A bearing cooling device for a water jet propulsion device, which is provided with a conduction path serving as water.