JP4606653B2 - Flexible connection structure and small planing boat having the connection structure - Google Patents

Description

[0001]
BACKGROUND OF THE INVENTION
The present invention relates to a flexible connection structure of a double pipe for connecting a double pipe composed of an outer pipe and an inner pipe, each having a different vibration system, and a small planing boat (Personal Watercraft ( Personal watercraft); also called PWC).
[0002]
[Background Art and Problems to be Solved by the Invention]
Small planing boats, for example, so-called jet propulsion type small planing boats have been widely used in recent years for leisure, sports or rescue. In this jet propulsion type personal watercraft, generally, water sucked from a water inlet provided on the bottom of the boat is pressurized and accelerated by a water jet pump and propelled backwards to propel the hull.
[0003]
And, in the case of this jet propulsion type personal watercraft, by changing the direction of water injection to the left and right by swinging the steering nozzle located behind the injection port of the water jet pump to the left and right, Steer the boat to the right or left side.
[0004]
By the way, in the case of a jet propulsion type personal watercraft, the engine is disposed on the hull via an engine mount member. Further, the second exhaust pipe connected to the tip (rear flow) side of the first exhaust pipe attached integrally to the engine is also a water arranged on the hull via another mount member. Attached to the muffler.
Therefore, the engine generates vibration inherent to the engine due to operation (continuous explosion) and the natural frequency of the engine, and the second exhaust pipe is transmitted from the engine via a hull or the like. Depending on the vibration and the natural frequency of the water muffler and the second exhaust pipe, a vibration different from that of the engine is exhibited.
When connecting the first exhaust pipe, which is integrally fixed to the engine side, and the second exhaust pipe, which is integrally fixed to the water muffler, which are different in these two vibration systems, the connection is generally possible. This is performed through a flexible material, specifically, a tube such as a rubber tube.
[0005]
For this reason, it is necessary to suppress the exhaust gas temperature within the range of the heat resistance performance of the rubber tube of these connecting portions. Specifically, the cooling water is guided to the first exhaust pipe portion and the second exhaust pipe portion to make it water-cooled. In addition, the cooling water is led into the wet exhaust system, that is, the exhaust pipe, and the cooling water is exhausted. The exhaust gas temperature is lowered by contacting with the rubber tube, and the connection by the rubber tube is made possible.
[0006]
In other words, with the knowledge of the increase in exhaust pressure that affects engine performance, the current situation is that a wet exhaust system must be adopted because of the heat resistance of the exhaust pipe connection portion as described above.
[0007]
The present invention has been made in view of such a situation, and it is not necessary to introduce cooling water into the exhaust pipe, that is, a flexible connection structure of a double pipe that can employ a dry exhaust system that can reduce exhaust pressure. The first object is to provide a small planing boat equipped with the connection structure.
[0008]
[Means for Solving the Problems]
The present invention can solve the above problems by a double-pipe flexible connection structure having the following configuration. That is,
The flexible connection structure of the double pipe line according to the first invention is a flexible connection for mutually connecting the double pipes composed of the outer pipe and the inner pipe having different vibration systems while maintaining the sealing function. Structure,
Each inner tube of the double tube, the protrusion-retraction freely movable tube together when respectively disposed, the movable tube comprises a distal end portion a flange portion in surface contact with each other by bending the outer radial direction at the tip ,
Between the flange portion of the movable tube and the end portion of the double tube, an elastic member that urges the movable tube in a protruding direction is interposed,
Each outer pipe of the double pipe is connected with a tube made of a flexible material whose inner peripheral surface is in surface contact with the outer peripheral surface of the outer pipe, and both ends of the tube are fixed by fixing means. It was connected to each end of the outer tube.
[0009]
Thus, according to the flexible connection structure configured as described above, the movable tubes arranged so as to protrude and retract with respect to the inner tube are urged against each other by the elastic member. Since the flange portions are in surface contact with each other, even if the first exhaust pipe and the second exhaust pipe to be connected have different vibration systems, the vibration is directly applied from one movable pipe to the other movable pipe. Without contact and substantially maintaining the sealing function and contacting. As a result, the exhaust gas can pass through the movable tube without leaking to the outside of the movable tube.
In addition, the outer pipes of the double pipes are mutually connected by a tube made of a flexible material, and the outer pipe and the tube are connected by a fixing means such as a band or an adhesive. The connecting portion between the tubes can be connected while maintaining a sealing function without directly transmitting vibration.
Therefore, if the inner tube and the movable tube are made of a material having high heat resistance, for example, a stainless tube, the exhaust gas itself can be passed through without lowering, that is, a wet exhaust system can be realized.
[0010]
In the flexible connection structure of the double conduit according to the first aspect of the invention, the outer peripheral surface of the movable tube is disposed so as to substantially contact the inner peripheral surface of the projecting inner tube,
The elastic member is a coil spring, and when the coil spring is interposed between the connection wall between the inner tube and the outer tube and the flange portion of the movable tube, the elastic member can be made compact. And it is preferable at the point which can be comprised so that sufficient urging | biasing force may be show | played.
[0011]
Moreover, in the flexible connection structure of the double conduit according to the first aspect of the invention, the movable tube is made of stainless steel, and at least the portions of the flange portions that are in surface contact with each other are smoothly finished. It is possible to realize a configuration that can be connected while maintaining a high heat resistance and a sealing function.
[0012]
Moreover, the flexible connection structure of the double pipe line concerning this 2nd invention is for mutually connecting the double pipes which consist of an outer pipe and an inner pipe with different vibration systems, maintaining a sealing function. A flexible connection structure,
The inner pipe of the double pipe is connected by a flexible inner pipe formed in a bellows shape with a thin plate made of a material having high heat resistance, and both end portions thereof are connected to each other by a fixing means. Connected to the end,
A pair of outer pipes of the double pipe are connected by a flexible outer pipe formed in a bellows shape with a thin plate made of a material having a lower heat resistance than the flexible inner pipe, and both ends thereof are to be connected by a fixing means. It was connected to each end of the outer tube.
[0013]
Thus, according to the double-pipe flexible connection structure configured in this way, the heat resistance performance is high with a simple configuration with a small number of parts, that is, the inside can pass high-temperature exhaust gas and has a sealing function. A flexible connection structure having can be realized.
[0014]
Moreover, in the flexible connection structure of the double conduit according to the second invention, the flexible inner tube is made of stainless steel, and the flexible outer tube is made of rubber. It becomes composition.
[0015]
A miniature planing boat for achieving the second object is a miniature planing boat configured to be propelled by a mounted engine.
6. At least a part of the exhaust passage of the personal watercraft is constituted by a double pipe, and a connection part is provided at an intermediate part of the double pipe, and the connection part is any one of claims 1 to 5. It is connected by the flexible connection structure described in the section.
[0016]
Thus, according to the small planing boat constructed in this way, the adoption of the dry exhaust system makes it possible to use a simple and low exhaust pressure and small size suitable for mounting a four-cycle engine. Become a planing boat.
[0017]
Further, in the above-mentioned small planing boat, a small planing boat capable of effectively reducing the exhaust gas temperature can be realized when cooling water is passed between the inner pipe and the outer pipe of the double pipe.
[0018]
Further, in the above personal watercraft, a rubber connection water pipe for passing cooling water across the connection part and bypassing the connection part is disposed at a connection part of the double pipe to be connected. If it is, it will become the structure which can cool two connected double pipes with one cooling water system path, and a cooling water system path will become simple.
[0019]
DETAILED DESCRIPTION OF THE INVENTION
Hereinafter, a jet propulsion personal watercraft according to an embodiment of the present invention will be specifically described with reference to the drawings, taking a small personal watercraft as an example.
[0020]
FIG. 1 is a diagram showing a schematic structure of an exhaust system inside a rear portion from a small planing boat engine showing a flexible connection structure of a double conduit according to an embodiment of the first invention, except for a deck and a hull on the right side surface. FIG. 2 is an enlarged view of the exhaust pipe connected to the engine shown in FIG. 1, and FIG. 3 is an enlarged view of the exhaust shown in FIGS. FIG. 4 is a partial enlarged view of the connecting portion of the pipe, FIG. 4 is a view taken along arrows IV-IV in FIG. 1 showing the arrangement of the engine and the exhaust pipe on its side, and FIG. FIG. 7 is a plan view of FIG. 6.
[0021]
6 and 7, A is a hull, and this hull A is composed of a hull H and a deck D covering the hull H, and a connection line connecting the hull H and the deck D all around is called a gunnel line G. In this embodiment, the gunnel line G is located above the waterline L of the personal watercraft.
[0022]
As shown in FIG. 7, a substantially rectangular opening 16 is formed on the upper surface of the hull A in a plan view extending in the longitudinal direction, slightly behind the center of the deck D, as shown in FIGS. Thus, a seat S for riding is disposed above the opening 16.
[0023]
The engine E is disposed in a space 20 having a “convex” cross section surrounded by the hull H and the deck D below the seat S.
The engine E is a multi-cylinder (four cylinders in this embodiment) four-cycle engine E, and the crankshaft 26 is mounted in a direction along the longitudinal direction of the hull A as shown in FIG. The output end of the crankshaft 26 is connected to the pump shaft 21S side of the water jet pump P, to which the impeller 21 is attached, via a propeller shaft 27 so as to be integrally rotatable. The outer periphery of the impeller 21 is covered with a pump casing 21C. Water taken from a water supply port 17 provided on the bottom surface of the personal watercraft is taken in via a water absorption passage and is added by a water jet pump P. It is configured to obtain a propulsive force through pressure / acceleration and discharge from the rear end injection port 21K through a pump nozzle (spout part) 21R whose water flow cross-sectional area becomes smaller as it goes backward.
[0024]
In FIG. 6, 21V is a stationary blade for rectifying water passing through the water jet pump P. 6 and 7, reference numeral 24 denotes a steering handle as steering operation means. By operating the handle 24 to the left and right, the steering nozzle 18 behind the pump nozzle 21R is swung to the left and right. When the water jet pump P is in operation, water is injected in that direction so that the boat can be steered in a desired direction. In the vicinity of the grip portion of the handle 24, a throttle lever Lt for operating the rotational speed of the engine E is provided via a throttle operation cable (not shown).
[0025]
As shown in FIG. 6, a bowl-shaped reverse deflector 19 is disposed above and behind the steering nozzle 18 so as to be able to swing downward about a horizontally disposed swing shaft 19a. The deflector 19 is configured to swing backward to a lower position behind the steering nozzle 18 so that water discharged rearward from the steering nozzle 18 can be turned forward to move backward.
[0026]
6 and 7, reference numeral 22 denotes a rear deck. The rear deck 22 is provided with an openable hatch cover 29, and a small capacity storage box is formed below the hatch cover 29. 6 or 7, reference numeral 23 denotes a front hatch cover, and a box (not shown) for storing equipment and the like is provided below the hatch cover 23.
[0027]
By the way, the personal watercraft according to the embodiment of the present invention includes an exhaust system having a double pipe connection structure as shown in FIGS. That is, as shown in FIGS. 1, 2, and 4, the first exhaust pipe 1 is integrally formed in the exhaust passage of each cylinder of the engine E in order to exhaust the exhaust gas from the combustion chamber to the outside. Has been attached to. As shown in enlarged views in FIGS. 2 and 3, the first exhaust pipe 1 is constituted by a double pipe composed of an inner pipe 1A and an outer pipe 1B.
1 to 4, a second exhaust pipe 2 is connected to the first exhaust pipe 1 by a flexible connection structure. The second exhaust pipe 2 is also constituted by a double pipe composed of an inner pipe 2A and an outer pipe 2B, as shown in enlarged views in FIGS.
The inner pipes 1A and 2A protrude from the other party as compared to the outer pipes 1B and 2B.
In the inner pipe 1A of the first exhaust pipe 1 and the inner pipe 2A of the second exhaust pipe 2, the movable pipes 1D and 2D protrude in the opposite direction so as to protrude and retreat toward the other party. It is arranged. As shown in an enlarged view in FIG. 3, each of these movable tubes 1D and 2D has flange portions 1d and 2d each having a surface F that is bent 90 degrees outward at the tip and in surface contact with each other. Have The surface F of each of the flange portions 1d and 2d is a surface that is smoothly finished so as to be in close surface contact (having a sealing function).
In this embodiment, each of these movable tubes 1D and 2D is made of stainless steel whose state is almost close to a mirror finish.
Further, the front end portion of the surface F is formed with locking portions 1e and 2e which are further bent by 90 degrees. On the first exhaust pipe 1 side, the movable pipe 1D is connected to the inner pipe 1A between the connecting wall 1C between the inner pipe 1A and the outer pipe 1B and the locking portion 1e, and the second A coil spring 4 is disposed so as to be biased toward the exhaust pipe 2 side. On the second exhaust pipe 2 side, the movable pipe 2D is connected to the inner pipe 2A between the connecting wall 2C between the inner pipe 2A and the outer pipe 2B and the locking portion 2e. A coil spring 4 is arranged so as to be biased toward the exhaust pipe 1 side. In this embodiment, the connection walls 1C and 2C are formed with water passage gaps 1r and 2r at a plurality of locations in the connection direction so that cooling water can be passed as will be described later.
Each of the inner pipes 1A and 2A is made of stainless steel in a state almost similar to a mirror finish.
The outer peripheral surface of the movable tube 1D is in a state of being in surface contact with the inner peripheral surface of the inner tube 1A and can be protruded and retracted toward the second exhaust tube 2 as described above. As described above, the outer peripheral surface of 2D is in a state of being in surface contact with the inner peripheral surface of the inner pipe 2A, and can protrude and retract toward the first exhaust pipe 1 side. Therefore, the exhaust gas hardly leaks to the outer pipes 1B and 2B from the gaps between the inner pipes 1A and 2A and the movable pipes 1D and 2D.
The first exhaust pipe 1 and the second exhaust pipe 2 are heat resistant so that the inner peripheral surface is in contact with one outer peripheral surface of the first or second exhaust pipe 1 or 2 when connected. The rubber tube 5 of the first exhaust pipe 1 and the second exhaust pipe 2 are connected to each other so that the surfaces F of the movable pipes 1D and 2D are in surface contact with each other. The coil spring 4 is pressed to a somewhat compressed state, and then the other end of the rubber tube 5 is connected to the outer peripheral surface of one of the remaining second or first exhaust pipes 2, 1. Connect so that the peripheral surfaces come in contact with each other. Then, in order to fix this state, the metal belt 6 as a fixing means is arranged around both ends of the rubber tube 5, the metal belt 6 is tightened, and the rubber tube 5 is attached. The first and second exhaust pipes 1 and 2 are fixed.
[0028]
The first exhaust pipe 1 and the second exhaust pipe 2 fixed in this manner are such that the engine E is in an operating state and the first exhaust pipe 1 and the second exhaust pipe 2 belong to different vibration systems. Even in such a case, the movable tubes 1D and 2D can protrude and retract in the contact direction (longitudinal direction) with respect to the inner tubes 1A and 2A, respectively, within a range in which the rubber tube 5 is elastically deformed. Since the surfaces F are in contact with each other in the radial direction of the tube, the surfaces F can be in contact with each other in the range where the surfaces F are in contact with each other. .
And both the said 1st exhaust pipe 1 and the 2nd exhaust pipe 2 can be comprised so that cooling water may be poured into the space between inner pipe | tube 1A, 2A and outer pipe | tube 1B, 2B. The cooling water can flow through the gaps 1r and 2r for passing water through the connection walls 1C and 2C.
Further, in such a case, the connection walls 1C and 2C of the first exhaust pipe 1 and the second exhaust pipe 2 are provided in a ring shape over the entire circumference, so that the respective inner pipe and outer pipe are formed at the end faces. In such a case, the cooling water passages of the first exhaust pipe 1 and the second exhaust pipe 2 may be connected as shown by a two-dot chain line in FIG. The connecting pipe 7 may be provided separately.
(Embodiment of the second invention)
By the way, it may replace with the said flexible connection structure of a double duct, and may comprise as shown in FIG. That is, the inner pipe 1A of the first exhaust pipe 1 and the inner pipe 2A of the second exhaust pipe 2 are connected by a flexible inner pipe 8 in which a stainless steel thin plate is formed in a bellows shape, and the flexible inner pipe 8 Each connecting portion with each inner pipe 1A, 2A is arranged so that the metal belt 6 as a fixing means goes around, and the metal belt 6 is fastened and fixed.
Further, the outer pipe 1B of the first exhaust pipe 1 and the outer pipe 2B of the second exhaust pipe 2, the bellows-like tube 9 made of heat-resistant rubber, each of which is an outer pipe 1B or an outer pipe 2B. Are connected so as to partially overlap with each other, and the overlapping portion between the tube 9 and the outer tube 1B or the outer tube 2B is arranged so that the metal belt 10 goes around, the metal belt 10 is tightened, and the rubber tube 9 Are fixed to the outer pipes 1B and 2B of the first and second exhaust pipes 1 and 2, respectively.
[0029]
The flexible connection structure of the double pipe line configured as described above also has the same effect as the above-described embodiment of the first invention. That is, even when the first exhaust pipe 1 and the second exhaust pipe 2 belong to different vibration systems, the flexible inner pipe 8 made of bellows-like stainless steel and the rubber tube 9 are A seal function can be provided and connected without being affected by the difference between these vibrations.
In this case, a very simple connection structure is obtained.
[0030]
【The invention's effect】
According to the present invention, a dry exhaust system that can not be employed due to the heat resistance performance of the connecting portion can be easily employed, and therefore the exhaust efficiency of the engine can be increased.
[0031]
In addition, by adopting the above-mentioned double-pipe flexible connection structure in the exhaust system of a small planing boat, it is possible to easily handle a long exhaust pipe unique to a 4-cycle engine in a narrow engine room. Therefore, it contributes to the promotion of the four-cycle engine in a small planing boat.
[Brief description of the drawings]
FIG. 1 is a right side deck and hull showing a schematic configuration of an exhaust system inside a rear part from an engine of a personal watercraft showing a flexible connection structure of a double conduit according to an embodiment of the first invention; It is a partial side view in the state which removed.
2 is an enlarged view in a state where a connection portion showing a configuration of a connection portion of an exhaust pipe from the engine shown in FIG. 1 is cut away. FIG.
3 is a partially enlarged view of a connection portion of the exhaust pipe shown in FIGS. 1 and 2. FIG.
4 is a view taken in the direction of arrows IV-IV in FIG. 1, showing the arrangement of the engine and the exhaust pipes on its side.
FIG. 5 is a partially enlarged view corresponding to FIG. 3 showing a configuration of a flexible connection portion of a double pipe line according to an embodiment of the second invention.
FIG. 6 is an overall side view of a jet propulsion personal watercraft according to an embodiment of the present invention.
7 is an overall plan view of the personal watercraft shown in FIG. 6. FIG.
[Explanation of symbols]
DESCRIPTION OF SYMBOLS 1 ... 1st exhaust pipe 1A ... Inner pipe 1B ... Outer pipe 1D ... Movable pipe 1d ... Flange part 2 ... 2nd exhaust pipe 2A ... Inner pipe 2B ... Outer pipe 2D ... Movable Pipe 2d …… Flange part 4 …… Coil spring (elastic member)
5 ... Tube 6 ... Metal belt (fixing means)

Claims (6)

It is a flexible connection structure for connecting two pipes consisting of an outer pipe and an inner pipe with different vibration systems to each other while maintaining a sealing function.
Each inner tube of the double tube, the protrusion-retraction freely movable tube together when respectively disposed, the movable tube comprises a distal end portion a flange portion in surface contact with each other by bending the outer radial direction at the tip ,
Between the flange portion of the movable tube and the end portion of the double tube, an elastic member that urges the movable tube in a protruding direction is interposed,
Each outer pipe of the double pipe is connected with a tube made of a flexible material whose inner peripheral surface is in surface contact with the outer peripheral surface of the outer pipe, and both ends of the tube are fixed by fixing means. A flexible connection structure of a double conduit characterized by being connected to each end of the outer tube. The outer peripheral surface of the movable tube is disposed so as to be substantially in contact with the inner peripheral surface of the projecting inner tube,
The elastic member is a coil spring, and the coil spring is interposed between a connection wall between the inner tube and the outer tube and a flange portion of the movable tube. The flexible connection structure of the double conduit according to 1.   The flexible connection structure for a double pipe according to claim 1 or 2, wherein the movable pipe is made of stainless steel, and at least a portion of the flange portion in surface contact with each other is smoothly finished. In a small planing boat configured to be propelled by an onboard engine,
At least part of the exhaust passage of this small planing boat is composed of a double pipe,
A small planing boat characterized in that there is a connecting portion at an intermediate portion of the double pipe, and the connecting portion is connected by the flexible connecting structure according to any one of claims 1 to 3. . 5. The personal watercraft according to claim 4 , wherein cooling water is passed between the inner pipe and the outer pipe of the double pipe. Across the connecting portion, wherein the rubber connecting water passage pipe which passed through the cooling water bypasses the connecting portion, characterized in that it is arranged in the connection portion of the double pipe to be connected Item 5. A personal watercraft according to item 5 .

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