Patent ID: 6461205
Filing Date: 2002-10-08
Classification: B63H,F15B

Abstract:
A hydraulic circuit of a tilt device for a marine propulsion unit comprising:the marine propulsion unit being supported to a mounting bracket fixed to a hull in a freely tilting manner, a tilt cylinder device being supported to a side of the mounting bracket is connected to the marine propulsion unit, and a trim cylinder device supported to a side of the mounting bracket being brought into contact with the marine propulsion unit; the tilt cylinder device being structured such as to section a first chamber which receives a piston rod and a second chamber which does not receive the piston rod, by a piston, and be provided with an absorber valve allowing an oil to flow from the first chamber to the second chamber in the piston and with no free piston in a lower portion of the piston; the trim cylinder device sectioning a first chamber which receives a piston rod and a second chamber which does not receive the piston rod, by a piston; and a working fluid supply/discharge device which extends and contracts the tilt cylinder device and the trim cylinder device so as to tilt the marine propulsion unit by supplying and discharging the working fluid within a tank pressure fed by a pump to the tilt cylinder device and the trim cylinder device, wherein a throttle is provided in a communicating passage connecting the first chamber of the trim cylinder to the tank.