Water jet propulsion watercraft

Abstract

A water jet propulsion watercraft includes a hull, an engine attached to the hull, a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull, a bucket arranged to be disposed in a manner enabling movement between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction, a hydraulic cylinder arranged to be disposed in an interior of the hull and to move the bucket between the forward drive position and the reverse drive position, and an oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.

1 . A water jet propulsion watercraft comprising:
 a hull;   an engine attached to the hull;   a jet propulsion device arranged to be driven using an output of the engine and to jet water toward a rear of the hull from a jet port provided on an outer side of the hull;   a bucket arranged to be movable between a forward drive position of not blocking the water jetted from the jet port of the jet propulsion device and a reverse drive position of blocking the water jetted from the jet port and, at the reverse drive position, to convert a jetting direction of the water jetted rearward from the jet port to a forward direction;   a hydraulic cylinder disposed in an interior of the hull and arranged to move the bucket between the forward drive position and the reverse drive position; and   an oil passage arranged to connect the engine and the hydraulic cylinder and to cause a lubricating oil inside of the engine to pass through as a hydraulic oil of the hydraulic cylinder.   
   
   
       2 . The water jet propulsion watercraft according to  claim 1 , further comprising a cable arranged to transmit a driving force of the hydraulic cylinder to the bucket. 
   
   
       3 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the rod portion is arranged to move along a substantially front/rear direction of the hull. 
   
   
       4 . The water jet propulsion watercraft according to  claim 1 , wherein the engine includes a crankshaft and an oil pump arranged to be driven using a rotation of the crankshaft and to circulate the lubricating oil inside the engine, and the oil pump is arranged to feed the lubricating oil to the hydraulic cylinder. 
   
   
       5 . The water jet propulsion watercraft according to  claim 4 , further comprising an oil storage portion arranged to store the lubricating oil therein, and a relief valve arranged to be able to pass the lubricating oil fed to the hydraulic cylinder by the oil pump to the oil storage portion. 
   
   
       6 . The water jet propulsion watercraft according to  claim 5 , wherein the oil storage portion is provided at a lower portion of the engine and below the relief valve. 
   
   
       7 . The water jet propulsion watercraft according to  claim 5 , wherein the oil pump includes a first oil pump arranged to deliver the lubricating oil from the oil storage portion to an inside of the engine to lubricate the inside of the engine, and a second oil pump arranged to deliver the lubricating oil that has lubricated the inside of the engine into the oil storage portion, and the second oil pump is arranged to have a lower discharge pressure than a discharge pressure of the first oil pump and is arranged to feed the lubricating oil to the hydraulic cylinder. 
   
   
       8 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder includes a cylinder portion, and a piston portion arranged to be slidable along an inner wall of the cylinder portion and to be driven to displace the bucket between the forward drive position and the reverse drive position, and the water jet propulsion watercraft further comprises a valve disposed in the oil passage and arranged to change a drive direction of the piston portion by changing a flow direction of the lubricating oil in the oil passage, and a switch arranged to be operable by a rider, and the valve is arranged to change the drive direction of the piston in response to the operation of the switch. 
   
   
       9 . The water jet propulsion watercraft according to  claim 8 , further comprising a control unit arranged to control the valve and the engine, and a rotational speed detection unit arranged to detect a rotational speed of the engine, wherein the control unit is arranged to lower the rotational speed of the engine to less than a predetermined value and thereafter control the valve to change the drive direction of the piston portion when the rotational speed of the engine is not less than the predetermined value and the rider operates the switch. 
   
   
       10 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder is disposed near the engine in an interior of the hull. 
   
   
       11 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder is supported by the engine. 
   
   
       12 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder is disposed inward relative to both sides of the engine in a width direction of the engine in plan view. 
   
   
       13 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder is supported by an upper portion of the engine. 
   
   
       14 . The water jet propulsion watercraft according to  claim 2 , wherein a direction in which the cable is pushed and pulled by the hydraulic cylinder is substantially parallel to an axial direction of the cylinder portion of the hydraulic cylinder. 
   
   
       15 . The water jet propulsion watercraft according to  claim 1 , further comprising a seat to be straddled by a rider, wherein the hydraulic cylinder is disposed below the seat. 
   
   
       16 . The water jet propulsion watercraft according to  claim 1 , further comprising an air introduction portion arranged to introduce air into an interior of the hull, the air introduction portion extending from an upper portion of the hull to below the interior of the hull in which the engine is disposed, wherein the hydraulic cylinder is disposed upward relative to a lower end portion of the air introduction portion. 
   
   
       17 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder is disposed at rearward of the engine. 
   
   
       18 . The water jet propulsion watercraft according to  claim 1 , further comprising a position holding member arranged to hold the bucket at the forward drive position. 
   
   
       19 . The water jet propulsion watercraft according to  claim 1 , wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and a portion of the rod portion that is housed inside the cylinder portion is greater when the bucket is at the forward drive position than when the bucket is at the reverse drive position. 
   
   
       20 . The water jet propulsion watercraft according to  claim 2 , wherein the hydraulic cylinder includes a cylinder portion, a piston portion arranged to slide along an inner wall of the cylinder portion, and a rod portion connected to the piston portion, and the water jet propulsion watercraft further comprises a link mechanism connected to the rod portion of the hydraulic cylinder and the cable and arranged to move the cable in a direction opposite to a movement direction of the rod portion.