Valve timing adjusting apparatus for internal combustion engine

• US 20020043231A1
• Filed: 05/07/2001
• Published: 04/18/2002
• Est. Priority Date: 08/09/2000
• Status: Active Grant

• Current Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Original Assignee: Mitsubishi Denki Kabushiki Kaisha (Mitsubishi Electric Corporation)
• Inventors: Hase, Hirofumi
• Granted Patent: US 6,523,511 B2
• Time in Patent Office: Days
• US Class Current: 123/90.15
• CPC Class Codes: F01L 1/34 characterised by the provision of means for changing the timing of the valves without changing the duration of opening and without affecting the magnitude of the valve lift
• CPC Class Codes: F01L 1/344 changing the angular relationship between crankshaft and camshaft, e.g. using helicoidal gear
• CPC Class Codes: F01L 1/3442 using hydraulic chambers with variable volume to transmit the rotating force
• CPC Class Codes: F01L 1/356 making the angular relationship oscillate , e.g. non-homokinetic drive
• CPC Class Codes: F01L 2001/34453 Locking means between driving and driven members
• CPC Class Codes: F01L 2001/34473 Lock movement perpendicular to camshaft axis
• CPC Class Codes: F01L 2001/34483 Phaser return springs
• CPC Class Codes: F01L 2800/00 Methods of operation using a variable valve timing mechanism
• CPC Class Codes: Y10T 74/2102 Adjustable

Abstract

In a valve timing adjusting apparatus, a locking hole 8 is formed in the external peripheral surface P of the boss of a rotor 3, into which the end portion of a locking pin 7a of the locking mechanism 7 is fitted when the rotor 3 is at the most advanced position, and in the external peripheral surface of the rotor, there is further formed a stepped portion 9 in a continuing manner from the locking hole 8 at a position deviated from the locking hole either in the advancing direction or the retarding direction in such a manner that it is formed lower than the external peripheral surface P, yet higher than the bottom of the locking hole 8, having two tapers 10, 11 respectively at the boarder between the stepped portion 9 and the external peripheral surface P, and that between the stepped portion 9 and the locking hole 8. Due to this construction, even though the rotor 3 is not cramped by the locking pin 7a during the engine-stop period, when the engine is resumed to start, the locking pin 7a is fitted into the locking hole 8 at least within one rotation of camshaft by the cam reaction force, and the rotor 3 is thus cramped at its reference position, enabling thereby an engine starting operation without causing any strange noise, a vibration and so on.

Claims

1. A valve timing adjusting apparatus comprising:

a shoe case, which rotates in synchronism with a crankshaft of an engine side, and having a plurality of shoes which are protruded from the inner surface of said shoe case and composing a plurality of hydraulic chambers,

a rotor, which is rotatably accommodated in said shoe case, and is formed with a plurality of vanes, said vanes dividing each of said plurality of hydraulic chambers into an advancing hydraulic chamber and a retarding hydraulic chamber, and

a locking member, which is shiftable in the radial direction of said rotor, and can be fitted in and/or disengaged from a locking hole formed in the external peripheral surface of said rotor,

wherein there is further formed a stepped portion in the external peripheral surface of said rotor in a continuing manner from said locking hole at a position deviated from said locking hole either in the advancing direction or retarding direction, said stepped portion being formed lower than said external peripheral surface, yet higher than the bottom of said locking hole.

2. The valve timing adjusting apparatus according to claim 1, wherein said stepped portion is formed to be a substantially elongate hole.

3. The valve timing adjusting apparatus according to claim 1, wherein said stepped portion is made in a punched-out shape in the axial direction of the apparatus.

4. The valve timing adjusting apparatus according to claim 1, wherein two tapers are formed each at the boarder between the external peripheral portion of said rotor and said stepped portion, and at the boarder between said locking hole and said stepped portion, wherein the taper formed at the boarder between said locking hole and said stepped portion is made shorter, yet its inclination angle is greater, in comparison with the length and the inclination angle of the taper provided at the boarder between the external peripheral portion of said rotor and said stepped portion.

5. The valve timing adjusting apparatus according to claim 4, wherein the end portion of said locking member is formed with a tapered portion whose inclination angle is equal to or larger than that of said taper provided at the boarder between said locking hole and said stepped portion.

6. The valve timing adjusting apparatus according to claim 4, wherein the end portion of said locking member is formed with a surface truncated into a C shape or an R shape, which is larger than that of said taper provided at the boarder between said locking hole and said stepped portion.

7. The valve timing adjusting apparatus according to claim 6, wherein the area surrounding said stepped portion and said locking hole is processed by a quenching finish.

8. The valve timing adjusting apparatus according to claim 1, wherein at least one of said plurality of advancing hydraulic chambers is formed with a bias member for urging said rotor in the advancing direction.

9. The valve timing adjusting apparatus according to claim 1, wherein said locking hole is formed at a position corresponding to the reference position at the engine starting time, which is between the most advanced position and the most retarded position.

10. The valve timing adjusting apparatus according to claim 9, characterized in that it is provided at the exhaust side camshaft.

11. The valve timing adjusting apparatus according to claim 9, characterized in that it is provided at the intake side camshaft.

13. The valve timing adjusting apparatus according to claim 12, wherein said rotor is further formed with two stepped portions in its external peripheral surface in a continuing manner from a locking hole at a position deviated from said locking hole in both the advancing direction and the retarding direction in a symmetrical manner, said stepped portion being formed lower than said external peripheral surface, yet higher than the bottom of said locking hole.

14. The valve timing adjusting apparatus according to claim 13, each of said stepped portions are formed with a plurality of stairs.

16. The valve timing adjusting apparatus according to claim 15, wherein even in a state that the spring urging the locking member in the diametrically inner direction of the apparatus is extended to the utmost level, thereby to fit said locking member into said locking hole formed in the external peripheral surface, the load of the spring is set in such a manner as to be larger than the centrifugal force applied to the locking member or than the force equivalent to the pressure of the residual oil in the apparatus at the engine starting time.

12. A valve timing adjusting apparatus comprising a locking member for controlling the free rotation of a casing that rotates in synchronism with a crank shaft at the internal combustion engine side and of a rotor rotatavely provided in said casing, said locking member being fitted to the substantially intermediate position between the most advanced position and the most retarded position, wherein said locking member is composed of a far end portion, which is formed in a tapered shape, or truncated into a C shape or an R shape, and also a parallel portion.

15. A valve timing adjusting apparatus comprising a locking member for controlling the free rotation of a casing that rotates in synchronism with a crank shaft at the internal combustion engine side and of a rotor rotatavely provided in said casing, said locking member being fitted to the substantially intermediate position between the most advanced position and the most retarded position, and shiftable in the diametrical direction of the apparatus by a spring force and an oil pressure, wherein the load of said spring urging said locking member in the diametrical inner direction of the apparatus is set in such a manner as to be larger than the centrifugal force applied to said locking member or than the force equivalent to the pressure of the residual oil in the apparatus at the engine starting time.