Claims
- 1. A variable valve timing system comprising:
a housing member rotatable as a unit with either a crankshaft or a camshaft of an internal combustion engine; a rotor member relatively rotatably assembled on a shoe portion of the housing member and forming an advanced angle chamber and a retarded angle chamber at a vane portion in the housing member, said rotor member rotating as a unit with either the crankshaft or the camshaft of the internal combustion engine; a relative rotation controlling mechanism allowing relative rotation of the housing member and the rotor member by an unlock operation through supply of an operation fluid, and restricting relative rotation of the housing member and the rotor member by a lock operation through discharge of the operation fluid at a lock phase within an intermediate area from a most advanced angle phase to a most retarded angle phase excluding rotation limited phases of both ends; a fluid pressure circuit for controlling the operation fluid to be supplied to and discharged from the advanced angle chamber, the retarded angle chamber, and the relative rotation controlling mechanism; the relative rotation controlling mechanism being formed with a first controlling mechanism restricting the relative rotation to an advanced angle side when the first controlling mechanism is operated under the lock operation at the lock phase, and a second controlling mechanism restricting the relative rotation to a retarded angle side when the second controlling mechanism is operated under the lock operation at the lock phase; the fluid pressure circuit supplying and discharging the operation fluid to or from the advanced angle chamber through the first controlling mechanism, and supplying and discharging the operation fluid to or from the retarded angle chamber through the second controlling mechanism; a first passage connecting the advanced angle chamber with the first controlling mechanism and functioning as a throttle; and a second passage connecting the retarded angle chamber with the second controlling mechanism and functioning as a throttle.
- 2. The variable valve timing system according to claim 1, wherein the throttle function of the first passage is canceled when the rotor member is rotated relative to the housing member to the advanced angle side from the lock phase by more than a predetermined amount, and the throttle function of the second passage is canceled when the rotor member is rotated relative to the housing member to the retarded angle side from the lock phase by more than the predetermined amount.
- 3. The variable valve timing system according to claim 1, wherein each of the first and second controlling mechanisms includes a spring and a lock plate slidably positioned in a radially directed retracting groove formed in the housing member.
- 4. The variable valve timing system according to claim 3, wherein each lock plate includes an end portion slidably positionable in a respective lock groove formed in the rotor member.
- 5. The variable valve timing system according to claim 4, wherein one of the lock grooves has a sloping bottom surface extending from a deepest portion and becoming more shallow towards the retarded angle side, the other lock groove having a sloping bottom surface extending from a deepest portion and becoming more shallow towards the advancing angle side.
- 6. The variable valve timing system according to claim 4, wherein each of the lock grooves has a sloping bottom surface extending from a deepest portion, the deepest portion of each lock groove being positioned in opposition to the respective retracting grooves when the rotor member is positioned at the lock phase relative to the housing member.
- 7. The variable valve timing system according to claim 4, wherein the first passage connects one of the lock grooves t o the advanced angle chamber and the second passage connects the other lock groove to the retarded angle chamber.
- 8. A variable valve timing system comprising:
a housing member rotating as a unit with either a crankshaft or a camshaft of an internal combustion engine; a rotor member relatively rotatably assembled on a shoe portion of the housing member and forming an advanced angle chamber and a retarded angle chamber at a vane portion in the housing member, said rotor member rotating as a unit with either the crankshaft or the camshaft of the internal combustion engine; a relative rotation controlling mechanism allowing relative rotation of the housing member and the rotor member by an unlock operation through supply of an operation fluid, and restricting the relative rotation of the housing member and the rotor member by a lock operation through the discharge of the operation fluid at a lock phase within an intermediate area from a most advanced angle phase to a most retarded angle phase excluding rotation limited phase at both ends; a fluid pressure circuit controlling the operation fluid to be supplied to and discharged from the advanced angle chamber, the retarded angle chamber, and the relative rotation controlling mechanism; the relative rotation controlling mechanism comprising a first controlling mechanism restricting the relative rotation to an advanced angle side when the first controlling mechanism is operated under the lock operation at the lock phase, and a second controlling mechanism restricting the relative rotation to a retarded angle side when the second controlling mechanism is operated under the lock operation at the lock phase; the fluid pressure circuit supplying and discharging the operation fluid to or from the advanced angle chamber through the first controlling mechanism, and supplying and discharging the operation fluid to or from the retarded angle chamber through the second controlling mechanism; a first passage having a first narrow portion which communicates between the advanced angle chamber and the first controlling mechanism; and a second passage having a second narrow portion which communicates between the retarded angle chamber and the second controlling mechanism.
- 9. The variable valve timing system according to claim 8, further comprising:
a first wide portion disposed next to the first narrow portion; a second wide portion disposed next to the second narrow portion; the first narrow portion being disposed a predetermined distance toward the advanced angle side; and the second narrow portion being disposed a predetermined distance toward the retarded angle side.
- 10. The variable valve timing system according to claim 8, wherein the first passage also includes a first wide portion disposed in series with the first narrow portion in a peripheral direction of the rotor member, the first wide portion having a greater cross-sectional area than the first narrow portion.
- 11. The variable valve timing system according to claim 8, wherein the second passage also includes a second wide portion disposed in series with the second narrow portion in a peripheral direction of the rotor member, the second wide portion having a greater cross-sectional area than the second narrow portion.
- 12. The variable valve timing system according to claim 8, wherein each of the first and second controlling mechanisms includes a spring and a lock plate slidably positioned in a radially directed retracting groove formed in the housing member.
- 13. The variable valve timing system according to claim 12, wherein each lock plate includes an end portion slidably positionable in a respective lock groove formed in the rotor member.
- 14. The variable valve timing system according to claim 13, wherein one of the lock grooves has a sloping bottom surface extending from a deepest portion and becoming more shallow towards the retarded angle side, the other lock groove having a sloping bottom surface extending from a deepest portion and becoming more shallow towards the advancing angle side.
- 15. The variable valve timing system according to claim 13, wherein each of the lock grooves has a sloping bottom surface extending from a deepest portion, the deepest portion of each lock groove being positioned in opposition to the respective retracting grooves when the rotor member is positioned at the lock phase relative to the housing member.
- 16. The variable valve timing system according to claim 13, wherein the first passage connects one of the lock grooves to the advanced angle chamber and the second passage connects the other lock groove to the retarded angle chamber.
Priority Claims (1)
Number |
Date |
Country |
Kind |
2000-289400 |
Sep 2000 |
JP |
|
Parent Case Info
[0001] This application is based on and claims priority under 35 U.S.C. § 119 with respect to Japanese Application 2000-289400 filed on Sep. 22, 2000, the entire content of which is incorporated herein by reference.