Steering device and ship

Abstract

A steering device includes: a flow passage forming member including a first flow passage connecting to a first chamber and a second flow passage connecting to a second chamber; a movable member movable relative to the flow passage forming member; a seal member configured to seal a space between the movable member and the flow passage forming member when the seal member is in contact with the movable member and the flow passage forming member; an operation part capable of rotating an outboard motor; and a resistance reducing part configured to reduce a flow resistance so that a fluid flows between the first and second flow passages even with a pressure generated in the first chamber or the second chamber due to an operation of the operation part by a load equal to or lower than a predetermined load, when sealing is not made by the seal member.

What is claimed is: 
     
         1 . A steering device comprising:
 a flow passage forming member including a first flow passage connecting to a first chamber in a cylinder and a second flow passage connecting to a second chamber in the cylinder;   a movable member provided to be movable relative to the flow passage forming member and capable of being arranged between the first flow passage and the second flow passage;   a seal member arranged between the movable member and the flow passage forming member and configured to seal a space between the movable member and the flow passage forming member when the seal member is in contact with the movable member and the flow passage forming member;   an operation part capable of rotating an outboard motor when a pressure in the first chamber or the second chamber is increased and capable of applying a pressure to the first chamber or the second chamber to rotate the outboard motor when the operation part is manually operated; and   a resistance reducing part configured to reduce a flow resistance so that a fluid flows between the first flow passage and the second flow passage even with a pressure generated in the first chamber or the second chamber due to an operation of the operation part by a load equal to or lower than a predetermined load, when sealing is not made by the seal member.   
     
     
         2 . The steering device according to  claim 1 , wherein
 the movable member has a cylindrical part that is fitted in a hole formed in the flow passage forming member and communicating with the second flow passage,   the resistance reducing part is a through-hole formed in the cylindrical part, and   when sealing is made by the seal member, the through-hole is located inside the hole, and when sealing is not made by the seal member, the through-hole is located outside the hole so that the fluid flows between the first flow passage and the second flow passage via the through-hole.   
     
     
         3 . The steering device according to  claim 1 , wherein
 the movable member has a cylindrical part that is fitted in a hole formed in the flow passage forming member and communicating with the second flow passage, and   the resistance reducing part is a ring-shaped flow passage formed between an outer peripheral surface of the cylindrical part and an inner peripheral surface of the second flow passage.   
     
     
         4 . The steering device according to  claim 2 , wherein
 the movable member has a first protrusion, which protrudes to have an outer diameter larger than an outer diameter of the cylindrical part and is in contact with the seal member, on a further downstream side than the cylindrical part in a flow direction from the second flow passage toward the first flow passage, and a second protrusion, which protrudes to have an outer diameter larger than the outer diameter of the first protrusion, on a further downstream side than the first protrusion in the flow direction.   
     
     
         5 . The steering device according to  claim 3 , wherein
 the movable member has a first protrusion, which protrudes to have an outer diameter larger than an outer diameter of the cylindrical part and is in contact with the seal member, on a further downstream side than the cylindrical part in a flow direction from the second flow passage toward the first flow passage, and a second protrusion, which protrudes to have an outer diameter larger than the outer diameter of the first protrusion, on a further downstream side than the first protrusion in the flow direction.   
     
     
         6 . The steering device according to  claim 4 , further comprising a truncated conical connection path formed concentrically with the second flow passage on a further downstream side than the second flow passage in the flow direction and having an outer diameter that becomes larger toward a downstream side in the flow direction. 
     
     
         7 . The steering device according to  claim 5 , further comprising a truncated conical connection path formed concentrically with the second flow passage on a further downstream side than the second flow passage in the flow direction and having an outer diameter that becomes larger toward a downstream side in the flow direction. 
     
     
         8 . The steering device according to  claim 1 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         9 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 1 .   
     
     
         10 . The steering device according to  claim 2 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         11 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 2 .   
     
     
         12 . The steering device according to  claim 3 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         13 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 3 .   
     
     
         14 . The steering device according to  claim 4 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         15 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 4 .   
     
     
         16 . The steering device according to  claim 5 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         17 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 5 .   
     
     
         18 . The steering device according to  claim 6 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.   
     
     
         19 . A ship comprising:
 a ship body; and   the steering device configured to change a traveling direction of the ship body according to  claim 6 .   
     
     
         20 . The steering device according to  claim 7 , wherein the movable member is cylindrical and has a seating surface provided at an end portion on an opposite side to the second flow passage in a center line direction, a spherical valve body being contacted to the seating surface, and
 the steering device further comprising a cap configured to accommodate therein the valve body and a pressing part for pressing the valve body to the seating surface, together with the movable member, and having a communication hole provided on a further opposite side to the second flow passage than the valve body and configured to communicate an inside and an outside of the cap.