# US 5,701,858 A · Variable valve timing mechanism of engine > Agents: this data is available as JSON from the patentgrep API and MCP server — see https://patentgrep.com/llms.txt - Number: US 5,701,858 A - Document ID: US5701858A - Status: Granted - Kind: A - Application number: 08/805,525 - Filed: 1997-02-26 - Granted: 1997-12-30 - Earliest claimed: 1996-02-27 - Assignees: Toyota Jidosha Kabushiki Kaisha - Inventors: Yoshihito Moriya - Web page: https://patentgrep.com/patent/US5701858A ## CPC - F01L 1/34406: {the helically teethed sleeve being located in the camshaft driving pulley} - F01L: CYCLICALLY OPERATING VALVES FOR MACHINES OR ENGINES ## Abstract A variable valve timing control device includes a camshaft for actuating an intake valve, and an inner gear is provided with the distal end of the camshaft. A sprocket having a first surface and a second surface surrounds the inner gear. A ring gear is placed between the camshaft and the sprocket. A cover is fixed to the inner gear, and the cover defines a first hydraulic pressure chamber between it and the inner gear. A flange is provided with the inner gear, and the cover defines a second hydraulic pressure chamber. A first clearance is defined between the first surface and the cover and communicates with the first hydraulic pressure chamber. A second clearance is defined between the second surface and the flange and communicates with the second hydraulic pressure chamber. An intermediate surface is provided on the sprocket, facing a direction opposite to that faced by the second surface in the second hydraulic pressure chamber. The intermediate surface has an area greater than that of the second surface. ## Claims ### Claim 1 An apparatus for adjusting the valve timing of at least one of an intake valve and an exhaust valve of an engine, the apparatus comprising: a camshaft for actuating one of said intake valve and said exhaust valve; a rotary member surrounding a distal end of said camshaft, said rotary member having a first surface and a second surface for respectively receiving fluid pressure from opposite directions; a gear member positioned between said camshaft and said rotary member, said gear member being arranged to move in an axial direction to change the relative rotational relationship between said camshaft and said rotary member; a first cover fixed to the distal end of the camshaft, wherein said first cover defines a first chamber between the first cover and the gear member for receiving fluid pressure to move the gear member axially; a second cover fixed to the camshaft, wherein said second cover defines a second chamber between the second cover and the gear member for receiving fluid pressure to move said gear axially; a first clearance defined between the first surface and the first cover to communicate with the first chamber; a second clearance defined between the second surface and the second cover to communicate with the second chamber; and a third surface provided on said rotary member between the first surface and the second surface, said third surface being arranged to receive a force resulting from fluid pressure directed opposite to a force resulting from the fluid pressure received by the second surface, wherein said third surface has an area greater than that of said second surface. ### Claim 2 (depends on 1) The apparatus as set forth in claim 1, further comprising: first outer teeth fixed to the camshaft; first inner teeth fixed to the rotary member; a ring gear formed by said gear member; second outer teeth fixed to the ring gear, wherein said second outer teeth engage the first inner teeth for forming an outer coupling; second inner teeth fixed to the ring gear, wherein said second inner teeth engage the first outer teeth for forming an inner coupling; a helical spline included in at least one of the outer gear coupling and the inner gear coupling. ### Claim 3 (depends on 2) The apparatus as set forth in claim 2, wherein said rotary member comprises an outer surface and a first inner surface adjacent to said first surface, and a second inner surface adjacent to said second surface, and wherein said first inner surface has a diameter greater than that of said second inner surface. ### Claim 4 (depends on 3) The apparatus as set forth in claim 3, wherein said first cover has a first peripheral surface for sealing said first cover with respect to said rotary member by contacting said outer surface of said rotary member. ### Claim 5 (depends on 4) The apparatus as set forth in claim 4, wherein said second cover has a second peripheral surface for sealing said second cover with respect to said rotary member by contacting said second inner surface of said rotary member. ### Claim 6 (depends on 5) The apparatus as set forth in claim 5, further comprising driving means for driving the rotary member by transmitting power from the engine to the rotary member. ### Claim 7 (depends on 6) The apparatus as set forth in claim 6, wherein said engine has a crankshaft, and said driving means includes transmission means for connecting the crankshaft to the rotary member. ### Claim 8 (depends on 7) The apparatus as set forth in claim 7, wherein said rotary member includes a sprocket, and wherein said transmission means includes a chain. ### Claim 9 (depends on 1) The apparatus as set forth in claim 1, wherein said camshaft selectively opens and closes said intake valve. ### Claim 10 An apparatus for adjusting the valve timing of at least one of an intake valve and an exhaust valve of an engine, the apparatus comprising: a camshaft for actuating one of said intake valve and said exhaust valve; a rotary member surrounding a distal end of said camshaft, said rotary member having a first surface and a second surface for respectively receiving fluid pressure from opposite directions; a gear member positioned between said camshaft and said rotary member, said gear member being arranged to move in an axial direction to change the relative rotational relationship between said camshaft and said rotary member; a first cover fixed to the distal end of the camshaft, wherein said first cover defines a first chamber between the first cover and the gear member for receiving fluid pressure to move the gear member axially; a second cover fixed to the camshaft, wherein said second cover defines a second chamber between the second cover and the gear member for receiving fluid pressure to move said gear axially; a first clearance defined between the first surface and the first cover to communicate with the first chamber; a second clearance defined between the second surface and the second cover to communicate with the second chamber; a third surface provided on said rotary member between the first surface and the second surface, said third surface being arranged to receive a force resulting from fluid pressure directed opposite to a force resulting from the fluid pressure received by the second surface; a first inner surface provided on the rotary member adjacent to said first surface; and a second inner surface provided on the rotary member adjacent to said second surface, wherein said first inner surface has a diameter greater than that of said second inner surface, and wherein said engine comprises a crankshaft, and the torque of said crankshaft actuates said apparatus. ### Claim 11 (depends on 10) The apparatus as set forth in claim 10, wherein said rotary member has an outer surface and wherein said first cover has a first peripheral surface for sealing said first cover with respect to said rotary member by contacting said outer surface of said rotary member, and wherein said second cover has a second peripheral surface for sealing said second cover with respect to said rotary member by contacting said second inner surface of said rotary member.