Valve timing control system for internal combustion engine

• US 6,450,139 B1
• Filed: 10/04/2001
• Issued: 09/17/2002
• Est. Priority Date: 10/20/2000
• Status: Expired due to Fees

• Current Assignee: Hitachi, Ltd.
• Original Assignee: Unisia Jecs Corporation (Hitachi, Ltd.)
• Inventors: Watanabe, Kotaro
• Primary Examiner(s): Lo, Weilun
• Application Number:
  US09/969,662
• Publication Number:
  US 20020050257A1
• Time in Patent Office: 348 Days
• Field of Search: 123/90.15, 123/90.17, 123/90.31
• US Class Current: 123/90.17
• CPC Class Codes: F01L 1/3442 using hydraulic chambers with variable volume to transmit the rotating force
• CPC Class Codes: F01L 2001/0537 Double overhead camshafts [DOHC]
• CPC Class Codes: F02B 2275/18 DOHC [Double overhead camshaft]

Abstract

A valve timing control system for an internal combustion engine. The valve timing control system comprises a rotation control mechanism including a housing, and a vane rotor rotatably disposed inside the housing and having at least one vane section. The vane section defines a first chamber and a second chamber which are located on opposite sides of the vane section, hydraulic pressure being selectively supplied to and released from the first chamber and the second chamber so as to controllably accomplish a relative rotation of the vane rotor to the housing. The vane rotor is formed at its axially end section with a depression. A first camshaft is connected to the vane rotor by a cam bolt piercing the vane rotor along an axis of the vane rotor. A second camshaft is disposed parallel with the first camshaft. A first driving force transmission member is installed to the housing and connected to one of a crankshaft and the second camshaft. Additionally, a second driving force transmission member is installed to an end section of the first camshaft together with the vane rotor by the cam bolt and connected to the other of the crankshaft and the second camshaft. The second driving force transmission member includes a generally cup-shaped section having a cylindrical wall portion fitted on the end section of the first camshaft and fitted in the depression of the vane rotor.

Claims

1. A valve timing control system for an internal combustion engine, comprising:

a rotation control mechanism comprising a housing, and a vane rotor which is rotatably disposed inside the housing and has at least one vane section, the vane section defining a first chamber and a second chamber which are located on opposite sides of the vane section, a hydraulic pressure being selectively supplied to and released from the first chamber and the second chamber to controllably accomplish a relative rotation of the vane rotor to the housing, the vane rotor being formed at its axially end section with a depression;

a first camshaft connected to the vane rotor by a cam bolt piercing the vane rotor along an axis of the vane rotor;

a second camshaft disposed parallel with said first camshaft;

a first driving force transmission member connected to one of a crankshaft and said second camshaft, the housing of said rotation control mechanism having said first driving force transmission member; and

a second driving force transmission member installed to an end section of said first camshaft together with the vane rotor by the cam bolt and connected to the other of the crankshaft and said second camshaft, said second driving force transmission member comprising a generally cup-shaped section which has a cylindrical wall portion fitted on the end section of said first camshaft and fitted in the depression of the vane rotor,

wherein the vane rotor of said rotation control mechanism and the generally cup-shaped section of said second driving force transmission member are fixed together to the end section of said first camshaft upon tightening the cam bolt.

2. A valve timing control system as claimed in claim 1, further comprising a locating member disposed between the vane rotor and said second driving force transmission member and between said second driving force transmission member and said first camshaft.

3. A valve timing control system as claimed in claim 2, wherein said locating member is fixed to one of the vane rotor, said second driving force transmission member and said first camshaft, wherein two of the vane rotor, said second driving force transmission member and said first camshaft are formed respectively with first and second engaged sections to which said locating member engages, the two being other than the one.

4. A valve timing control system as claimed in claim 3, wherein said locating member is fixed to the generally cup-shaped section of said second driving force transmission member, wherein the vane rotor and said first camshaft are formed respectively with first and second engaged sections to which said locating member engages.

5. A valve timing control system as claimed in claim 4, wherein said locating member is an axially extending locating pin, wherein each of said engaged sections has a radially extending groove to which said locating pin engages.

6. A valve timing control system as claimed in claim 5, wherein each of said engaged sections has a radially extending surface defining the radially extending groove, said axially extending locating pin being axially separate from the radially extending surface with a clearance.

7. A valve timing control system as claimed in claim 1, wherein said first camshaft is an exhaust valve-side camshaft for driving exhaust valves, and said second camshaft is an intake valve-side camshaft for driving intake valves.

8. A valve timing control system as claimed in claim 1, wherein said first camshaft has a cylindrical end section inside which a tube is fixed, the tube having opposite end sections which are enlarged in diameter, the tube being located radially outside of the cam bolt to define a first passage in communication with the first chamber of said rotation control mechanism and a second passage in communication with the second chamber of said rotation control mechanism.

9. A valve timing control system as claimed in claim 8, wherein the generally cup-shaped section of said second driving force transmission member has a portion defining a through-hole in communication with the first passage defined between the tube and an inner peripheral surface of the cylindrical end section of said first camshaft, the first passage being in communication with one of the first and second chambers of said rotation control mechanism.

10. A valve timing control system as claimed in claim 9, wherein the first passage defined between the tube and the inner peripheral surface of the cylindrical end section of said first camshaft is in communication with the first chamber of said rotation control mechanism, the first chamber being a timing-advancing chamber which is to be supplied with hydraulic pressure to advance a valve timing.

11. A valve timing control system as claimed in claim 8, wherein the cam bolt is fixed in a condition of being inserted in a central bore formed in the vane rotor and a bolt insertion hole formed at a bottom wall portion of the generally cup-shaped section of said second driving force transmission member, wherein a first clearance is formed between an inner peripheral surface of the vane rotor defining the central bore and an outer peripheral surface of the cam bolt, and a second clearance is formed between an inner peripheral surface of the bottom wall portion defining the bolt insertion hole and the outer peripheral surface of the cam bolt, the second passage defined by an inner peripheral surface of the tube being communicated through the first and second clearances with one of the first and second chambers of said rotation control mechanism.

12. A valve timing control system as claimed in claim 11, wherein the second passage defined by the inner peripheral surface of the tube is in communication with the second chamber of said rotation control mechanism, the second chamber being a timing-retarding chamber which is supplied with hydraulic pressure to retard a valve timing.

13. A valve timing control system as claimed in claim 1, wherein the depression is defined by a cylindrical inner wall surface of the vane rotor, the cylindrical inner wall surface being coaxial with the vane rotor, wherein the cylindrical inner wall surface is in fitting contact with the cylindrical wall portion of the generally cup-shaped section of said second driving force transmission member.

14. A valve timing control system for an internal combustion engine, comprising:

a rotation control mechanism comprising a casing, and a vane rotor which is rotatably disposed inside the housing and comprises a generally cylindrical body section, and at least one vane section integral with and radially extending from the cylindrical body section, the vane section defining a timing-advancing chamber and a timing-retarding chamber which are located on opposite sides of the vane section, the vane rotor making a relative rotation to the housing in a first direction for advancing a valve timing upon supply of hydraulic pressure into the timing-advancing chamber, the vane rotor making a relative rotation to the housing in a second direction for retarding the valve timing upon supply of hydraulic pressure into the timing-retarding chamber, the second direction being opposite to the first direction, the vane rotor being formed at its axially end section with a depression generally coaxial with the cylindrical body section;

a change-over valve through which hydraulic pressure is selectively supplied to the timing-advancing chamber and the timing-retarding chamber in accordance with an engine operating condition;

a first camshaft coaxially connected to the body section of the vane rotor by a cam bolt piercing the body section of the vane rotor along an axis of the vane rotor;

a second camshaft disposed parallel with said first camshaft;

a first driving force transmission member connected to one of a crankshaft and said second camshaft, the housing of said rotation control mechanism coaxially having said first driving force transmission member; and

a second driving force transmission member coaxially installed to an end section of the first camshaft together with the vane rotor by the cam bolt and connected to the other of the crankshaft and said second camshaft, said second driving force transmission member comprising a generally cup-shaped section which comprises a cylindrical wall portion coaxial with the cylindrical body section of the vane rotor, the cylindrical wall portion being coaxially fitted on the end section of said first camshaft and having an end part fitted in the depression of the vane rotor of said rotation control mechanism,

wherein the vane rotor of said rotation control mechanism and the generally cup-shaped section of said second driving force transmission member are fixed together to the end section of said first camshaft upon tightening the cam bolt.

15. A V-type internal combustion engine having first and second banks of cylinders, comprising:

a first exhaust valve-side camshaft for driving exhaust valves, disposed in the first bank;

a second exhaust valve-side camshaft for driving exhaust valves, disposed in the second bank;

a first intake valve-side camshaft for driving intake valves, disposed in the first bank and located inside relative to said first exhaust valve-side camshaft, said first intake valve-side camshaft being parallel with said first exhaust valve-side camshaft;

a second intake valve-side camshaft for driving intake valves, disposed in the second bank and located inside relative to said second exhaust-side camshaft, said second intake valve-side camshaft being parallel with said second exhaust valve-side camshaft;

a first rotation control mechanism comprising a housing, and a vane rotor which is rotatably disposed inside the housing and has at least one vane section, the vane section defining a first chamber and a second chamber which are located on opposite sides of the vane section, hydraulic pressure being selectively supplied to and released from the first chamber and the second chamber to controllably accomplish a relative rotation of the vane rotor to the housing, the vane rotor being formed at its axially end section with a depression, the vane rotor being connected to said first exhaust valve-side camshaft by a cam bolt piercing the vane rotor along an axis of the vane rotor;

a first driving force transmission member connected to one of a crankshaft and said first intake valve-side camshaft, the housing of said first rotation control mechanism having said first driving force transmission member;

a second driving force transmission member installed to an end section of said first exhaust valve-side camshaft together with the vane rotor by the cam bolt and connected to the other of the crankshaft and said first intake valve-side camshaft, said second driving force transmission member comprising a generally cup-shaped section which has a cylindrical wall portion fitted on the end section of said first exhaust valve-side camshaft and fitted in the depression of the vane rotor, wherein the vane rotor of said first rotation control mechanism and the generally cup-shaped section of said second driving force transmission member are fixed together to the end section of said first exhaust valve-side camshaft upon tightening the cam bolt;

a second rotation control mechanism comprising a housing, and a vane rotor which is rotatably disposed inside the housing and has at least one vane section, the vane section defining a first chamber and a second chamber which are located on opposite sides of the vane section, hydraulic pressure being selectively supplied to and released from the first chamber and the second chamber to controllably accomplish a relative rotation of the vane rotor to the housing, the vane rotor being formed at its axially end section with a depression, the vane rotor being connected to said second exhaust valve-side camshaft by a cam bolt piercing the vane rotor along an axis of the vane rotor;

a third driving force transmission member connected to one of the crankshaft and said second intake valve-side camshaft, the housing of said second rotation control mechanism having said third driving force transmission member; and

a fourth driving force transmission member installed to an end section of said second exhaust valve-side camshaft together with the vane rotor by the cam bolt and connected to the other of the crankshaft and said second intake valve-side camshaft, said fourth driving force transmission member comprising a generally cup-shaped section which has a cylindrical wall portion fitted on the end section of said second exhaust valve-side camshaft and fitted in the depression of the vane rotor, wherein the vane rotor of said second rotation control mechanism and the generally cup-shaped section of said fourth driving force transmission member are fixed together to the end section of said second exhaust valve-side camshaft upon tightening the cam bolt.