JPH04201778A - Stern seal device in air cushion boat - Google Patents

Abstract

PURPOSE:To decrease stress in a lobe in the lowermost step while maintaining an essential seal function by separately providing an air supply means to the lowermost step lobe of the multistep type lobes for constituting a stern seal, and further relatively low setting an internal pressure of the lowermost step lobe. CONSTITUTION:A stern seal A, mounted below a stern part of an upper part ship body 1, is constituted of outer side film materials 5, 5a and an inner side film material 6 as a multistep type formed of four-step lobes a1 to a4 respectively as a bag-shaped structure. On the other hand, an air chamber 2, surrounded by the stern seal A, catamaran right/left ship bodies and a bow seal, is formed below the upper part ship body 1. Air supply means to each lobe a1 to a4 especially in the stern seal A are formed different from each other to supply air especially to the lowermost step lobe a4 from a supply air fan 7 through a supply air port 11 via three dampers 10 in a duct 8. Accordingly, compressed air of relatively low pressure is supplied to the lowermost step lobe a4.

Description

[Detailed Description of the Invention] [Field of Industrial Application] The present invention relates to an air cushion boat having a bow seal and a stern seal at the front and rear ends of the left and right hulls of a twin-hull type, and particularly to a multi-stage type boat that constitutes the stern seal. This invention relates to a stern sealing device for an air cushion, which allows the internal pressure of the lobes to be set appropriately.

[Conventional technology]

Various types of bow seals have been proposed for air cushion boats with twin-hulled port and starboard hulls, but in most cases a seal commonly known as a multi-lobe seal is used for the stern seal. ing.

This seal consists of several stacked bag-like structures called lobes made of flexible material, as shown in Figure 3.
The configuration of the multi-stage lobe stern seal will be explained by showing a cross-sectional shape of the four-stage lobe stern seal and the upper hull taken along a vertical plane along the longitudinal direction of the hull. This stern seal is installed under the upper hull 1, and is surrounded by a pair of side walls (twin-hulled left and right hulls) placed parallel to this plane at the front and back of this cross-sectional view, the upper hull, and the bow and stern seals. An air chamber 2 is formed in the closed portion.

The air chamber 2 is maintained at a high pressure by compressed air supplied from the air supply fan 7 through the duct 8 and the air supply port 11, so that the internal water level 3 is lower than the external water level 4.

The stern seal is made of a flexible membrane material, and consists of outer membrane materials 5, 5a that form the outer periphery, and an inner membrane material 6 that is located at the boundary line of the multi-stage lobes and serves to maintain the shape of the entire seal. . In order to prevent the high-pressure air in the air chamber 2 from leaking outside, it is necessary to store air at a higher pressure than the air chamber pressure inside the lobe, so the air is stored at a higher pressure than the air chamber pressure from the air supply fan 7 through the duct 8. It is common practice to adopt a configuration in which air is supplied from above the uppermost lobe through the air supply port 11, passes through an opening 9 provided in the inner membrane material 6, and is sequentially supplied to the lower lobes. be. The pressure loss caused by passing through these openings 9 is considered to be negligibly small, and the pressure within the lobes of each stage of the sole is generally considered to be the same [Problem to be Solved by the Invention] By the way, In the conventional air-arc boat as mentioned above, if the pressure in the air chamber 2 is kept the same, it is possible to reduce the stress in the sole material by increasing the number of stages of lobes that make up the stern seal. be. However, in order to do this, it is necessary to lower the pressure inside the lobes as the number of stages increases, and as the pressure inside the lobes approaches the pressure in the air chamber, there is a risk that the original function of the seal, which prevents air from leaking outside, may be impaired. .

The relationship between air pressure and the shape of the multi-lobe seal will be explained in more detail.

FIG. 4 shows dimensional symbols for each part of the multi-stage lobe seal used in the following explanation. Here, To-74 is the tension of the flexible membrane material, and R0 to R4 are the radius of curvature of each membrane material in the balanced state. Assuming that the air chamber pressure is Pc and the pressure inside the lobe is P (same for each stage), and ignoring the bending rigidity of the membrane material, Ps・R+= (P-Pc) from the balance between the tension and pressure of the membrane material. Ro=To=T+・
・・・・・・・・・・・・・・・・・・・・・・・・
・・・・・・・・・ (1) P Il” R2= T 2
・・・・・・・・・・・・・・・・・・・・・・・・
・Old and old...(2) Ps-R3=T3...
・・・・・・・・・・・・Dan・・・・・・・・・Dan・
(3) R8・R4=T 4 ...... River... Old and old... (4) is obtained. If the seal height is H, then from Figure 4 2・(R, 10R, +R8+R4)=H... River... (
5), so if the number of lobe seal stages is increased, R1-
Since R4 is small, and the tension of the membrane material is proportional to the radius of curvature as shown in equations (1) to (4), there is a possibility that the tension of the membrane material can be kept small.On the other hand, from equation (1), R+ = (
1-P C/ P-) "Ro・Mountain・'----
(6) is obtained, but if we consider that the value of R is determined by the balance with the hull dimensions, and that the value of Pc/P11 is determined to be an appropriate value for the purpose of maintaining sealing performance, the value of Ro is determined by itself ( Therefore, in a multi-stage lobe seal, if an appropriate PC/P value is adopted, the cross-sectional shape shown in Figure 5 is often obtained, and even if the number of stages is increased, R3
(Thus, the value of T+) does not become small. Therefore, when the air chamber pressure PC increases due to design requirements, even if a multi-stage seal is considered to be used to ensure the strength margin of the membrane material, the expected effect will not be obtained.

In order to reduce T, it is sufficient to bring R8 closer to Pc according to equation (6), and as a result, it is possible to obtain the cross-sectional shape shown in Figure 3, but the pressure inside the lobe and the air chamber If the difference between the pressure of It comes out. The present invention aims to solve the above-mentioned problems by appropriately setting the pressure in the multi-stage loading lobes that constitute the stern seal, and creating a well-balanced multi-stage lobe without impairing the original function of the seal. An object of the present invention is to provide a stern seal device for an air cushion boat, which is equipped with the following.

[Means to solve the problem]

In order to achieve the above object, the stern seal device for an air cushion boat of the present invention is provided with bow soles and stern seals made of flexible materials at the front and rear ends of the left and right twin-hulled hulls, respectively. In an air-soak boat that obtains buoyancy by dripping high-pressure air into an air chamber formed below the upper hull, which is surrounded by a bow sole and a stern seal and connects the left and right hulls, the stern sole has a bag-like structure. It is constructed by providing a plurality of lobes as a product in a multi-stage type, and an air supply means for the lowest lobe among the plurality of lobes is provided separately from an air supply means for the other lobes. The internal pressure of the lobe is set lower than the internal pressure of the other lobes.

[For production]

In the stern seal device for an air cushion boat of the present invention described above, among the multistage lobes constituting the stern seal,
Since the air supply means for the lowest lobe is provided separately from the air supply means for the other lobes, the internal pressure of each lobe can be appropriately adjusted.

In particular, the internal pressure of the lowest lobe is set lower than the internal pressure of the other lobes, so while sailing, the stress in the lowest lobe is reduced while maintaining the original sole function of the stern knoll. A lowering action is taken.

〔Example〕

Hereinafter, embodiments of the present invention will be explained with reference to the drawings.
FIG. 1 is a longitudinal cross-sectional view of a stern sealing device in an air cushion boat as a first embodiment, and FIG. 2 is a longitudinal cross-sectional view of the stern sealing device in an air cushion boat as a second embodiment.

In a first embodiment of the present invention, as shown in FIG. Almost the same as in the conventional case, it is constructed as a multi-stage type consisting of four stages of lobes a1 to a4 each as a bag-like structure, and this stern seal A, a twin-hull type left and right hull and a bow seal (not shown) An air chamber 2 surrounded by is formed below the upper hull 1.

A duct 8.3 dampers 10.1 final damper 10a is connected to the air supply fan 7 provided in the upper hull 1.
The air chamber 2 is maintained at a high pressure by the compressed air supplied through the air supply port If, so that the internal water level 3 is lower than the external water level 4.

In this embodiment, each lobe a1 in the stern seal A is particularly
The air supply means to ~a4 are different from each other, and the uppermost lobe al is supplied from the air supply fan 7 to the air supply port 11 of the duct 8.
``Second stage lobe a''
2 is supplied with air from the air supply fan 7 via one damper 10 in the duct 8 through the air supply port 11, and air is supplied from the air supply fan 7 in the duct 8 to the third stage lobe a3. Air is supplied through the air supply port 11 via two dampers 10,
Furthermore, air is supplied to the lowermost lobe a4 from the air supply fan 7 via the three dampers 10 in the duct 8 and through the air supply port 11.

In this way, air is supplied to the lobe a4 at the lowest stage with compressed air at a relatively lower pressure than the air supplied to the other lobes a1 to a3. The pressure is set lower than the internal pressure of the other lobes a1 to a3, but higher than the internal pressure of the air chamber 2 supplied via the final damper 10a.

Further, for the lobes a1 to a3 of the first to third stages, the internal pressure decreases from the upper stage to the lower stage, and the internal pressure of each of the lobes a1 to a4 is appropriately adjusted.

Furthermore, by changing the balance between the opening area of each damper 10.10a and the opening area of the air supply port 11 to the lobes a1 to a4 of each stage, the internal pressure of the lobes a1 to a4 of each stage can be finely adjusted. can do.

As described above, by setting the internal pressure of the lowest lobe a4 lower than the internal pressure of the upper lobes a1 to a3, the lowermost lobe a4 can be maintained while maintaining the sealing function of the stern seal A. The tension of the membrane materials 5, 5a constituting the lower part of the lobes can be kept low, and the upper lobes a1~
By setting a higher internal pressure for a3 than for the lowermost lobe a4, the stern seal A as a whole can maintain stability against disturbances.

In the first embodiment of the present invention, the inner membrane materials 6 forming the boundaries of the lobes a1 to a4 of each stage are individually attached to the lower part of the upper hull 1, but in the second embodiment of the present invention shown in FIG. In the example, all the inner membrane materials 6 are assembled together and attached to the lower part of the upper hull 1, and only the membrane material 5a forming the lower surface of the seal is attached separately. Thereby, the installation work of the stern seal A can be simplified.

In the case of this second embodiment as well, the air supply means for the lowermost lobe a4 is provided separately from the air supply means for the upper lobes a1 to a3, and the internal pressure of the lowermost lobe a4 is It is set lower than the internal pressure of the other lobes a1 to a3.

The internal pressure of the air chamber 2 is set lower than the internal pressure of the lobe a4 at the lowest stage.

As shown in Fig. 5, when the internal pressure of each of the multistage lobes al to a4 is kept constant, the radius of curvature on the outside of the rear end cannot be made small and the tension becomes excessive only in the lowest lobe a4. Therefore, almost the same tension reduction effect as in the first embodiment can be expected in the second embodiment of the present invention.

[Effects of the Invention] As detailed above, according to the stern seal device for an air cushion watercraft of the present invention, the following effects and advantages can be obtained.

(1) Among the multistage lobes that make up the stern seal, the means for supplying air to the lowest lobe is provided separately from the means for supplying air to the other lobes, making it possible to adjust the internal pressure of each lobe. done properly.

(2) By setting the internal pressure of the lowest lobe lower than that of the upper lobe, the membrane material forming the lower part of the lowermost lobe can be maintained while maintaining the sealing function of the stern seal. The tension can be kept low.

(3) By setting a higher internal pressure for each of the upper lobes than for the lowermost lobes, the stern seal as a whole can maintain stability against disturbances.

[Brief explanation of the drawing]

FIG. 1 is a longitudinal cross-sectional view showing a stern seal device in an air cushion boat as a first embodiment of the present invention, and FIG. 2 is a longitudinal cross-sectional view showing a stern sole device in an air cushion boat as a second embodiment of the present invention. FIG. 3 is a longitudinal cross-sectional view showing a stern sole device in a conventional air cushion boat, and FIG. 5 are longitudinal cross-sectional views showing the operating state of the stern seal device in a conventional air-motion watercraft. 1... Upper hull, 2... Air chamber, 3... Water surface inside the air chamber, 4... Water surface outside the hull, 5, 5a... Outer membrane material, 6... Inner membrane material , 7... air supply fan, 8.
...Air supply duct, 9...Opening, 10.10a...Damper, 11...Air supply port, A...Stern seal, al
~a4...robe. Agent Patent Attorney Yoshihiko Iinuma Figure 1 Figure 2

Claims (1)

[Claims] A bow seal and a stern seal made of flexible materials are provided at the front and rear ends of the left and right hulls of the twin-hull type, respectively, and the lower part of the upper hull is surrounded by the left and right hulls, the bow seal, and the stern seal, and connects the left and right hulls. In an air cushion boat that obtains buoyancy by filling an air chamber formed in The air supply means for the lower lobe is provided separately from the air supply means for the other lobes, and the internal pressure of the lowermost lobe is set lower than the internal pressure of the other lobes. , a stern sealing device in an air cushion boat.