Belt drive for auxiliary units of an internal combustion engine

• US 20050215392A1
• Filed: 05/18/2005
• Published: 09/29/2005
• Est. Priority Date: 11/26/2002
• Status: Active Grant

• Current Assignee: Peugeot Citroen Automobiles Societe Anonyme
• Original Assignee: Bayerische Motoren Werke AG
• Inventors: Lemberger, Heinz, Wimmer, Rudolf, Foessl, Peter, Wieser, Philipp
• Granted Patent: US 7,367,916 B2
• Time in Patent Office: Days
• US Class Current: 476/28
• CPC Class Codes: F01P 5/12 Pump-driving arrangements
• CPC Class Codes: F02B 67/06 driven by means of chains, belts, or like endless members
• CPC Class Codes: F16H 13/10 Means for influencing the pressure between the members
• CPC Class Codes: F16H 13/14 for automatically varying the pressure mechanically
• CPC Class Codes: F16H 7/02 with belts; with V-belts

Abstract

A belt drive for a secondary unit of an internal combustion engine includes a friction wheel drive having a friction wheel, a cam device for adjusting the engagement of the friction wheel to the drive wheel of the secondary unit, the cam device having a cam, a swivel arm by which the friction wheel is connected to the cam which is rotationally mounted on a side of the engine, and a spring biasing the swivel arm in a tension direction. The friction wheel is in permanent position of frictional engagement with a drive wheel of the secondary unit to drive the secondary unit and with an outside of a belt on a drive wheel of the internal combustion engine or of another secondary unit.

Claims

1. A belt drive for a secondary unit of an internal combustion engine, comprising:

a friction wheel drive having a friction wheel, wherein the friction wheel is in permanent position of frictional engagement with a drive wheel of the secondary unit to drive the secondary unit and with an outside of a belt on a drive wheel of the internal combustion engine or of another secondary unit;

a cam device for adjusting the engagement of the friction wheel to the drive wheel of the secondary unit, the cam device having a cam;

a swivel arm by which the friction wheel is connected to the cam which is rotationally mounted on a side of the engine;

a spring biasing the swivel arm in a tension direction.

2. The belt drive according to claim 1, wherein the cam is mounted with an eccentricity that is on the opposite side of the tension direction of the swivel arm relative to the center of rotation of the cam as starting position.

3. The belt drive according to claim 2, wherein the swivel arm is journaled through an eye formed in an end section remote from the friction wheel on the cam which has a recess coaxial with the cam axis with the spring that is under bias, and wherein the spring is fixed at one end on the engine side and is disposed at the other end acting rotationally on the cam.

4. The belt drive according to claim 3, wherein the cam is made of a plastic and is journaled for rotation on a metal bush that is disposed in the recess and accommodates the spring, wherein an end of the spring passes through the bottom of the metal bush and is fixed against rotation engaging conformingly in a cavity on the engine side, wherein through a bolt coaxial with the eccentric axis with the interposition of a cover of the eccentric device is forcibly abutted against an abutment surface on the engine side, and wherein the cam between the abutment surface and the protective cover is disposed with axial free play on the metal bush.

5. The belt drive according to claim 4, wherein the metal bush has on the cover side a marginal cutout corresponding to the adjustability of the friction wheel adapted accordingly in the circumferential direction for the free passage of the other end, pointing transversely of the cam axis, of the oil spring for rotational attachment to the cam, and wherein the metal bush has a wider marginal cutout for engagement by an antirotational projection disposed on the protective cover.

6. The belt drive according to claim 5, wherein the cam is in connection with the eye of the arm, with the interposition of an antifriction bushing, which arm is formed relatively closely to the eye with a fork-like friction wheel receiver, and wherein the cam of the arm is disposed between the secondary unit'"'"'s drive wheel and the drive wheel partially wrapped around by the belt is arranged on a post provided at the face of the internal combustion engine.

7. The belt drive according to claim 6, wherein the friction wheel comprises a spoked wheel formed of plastic, having a covering of a rubber material arranged on the outside circumference, and wherein the spoked wheel is urged against a bolt of the fork of the arm through an integrated and encapsulated rolling bearing.

8. The belt drive according to claim 1, wherein the swivel arm is journaled through an eye formed in an end section remote from the friction wheel on the cam which has a recess coaxial with the cam axis with the spring that is under bias, and wherein the spring is fixed at one end on the engine side and is disposed at the other end acting rotationally on the cam.

9. The belt drive according to claim 8, wherein the cam is made of a plastic and is journaled for rotation on a metal bush that is disposed in the recess and accommodates the spring, wherein an end of the spring passes through the bottom of the metal bush and is fixed against rotation engaging conformingly in a cavity on the engine side, wherein through a bolt coaxial with the eccentric axis with the interposition of a cover of the eccentric device is forcibly abutted against an abutment surface on the engine side, and wherein the cam between the abutment surface and the protective cover is disposed with axial free play on the metal bush.

10. The belt drive according to claim 9, wherein the metal bush has on the cover side a marginal cutout corresponding to the adjustability of the friction wheel adapted accordingly in the circumferential direction for the free passage of the other end, pointing transversely of the cam axis, of the oil spring for rotational attachment to the cam, and wherein the metal bush has a wider marginal cutout for engagement by an antirotational projection disposed on the protective cover.

11. The belt drive according to claim 9, wherein the cam is in connection with the eye of the arm, with the interposition of an antifriction bushing, which arm is formed relatively closely to the eye with a fork-like friction wheel receiver, and wherein the cam of the arm is disposed between the secondary unit'"'"'s drive wheel and the drive wheel partially wrapped around by the belt is arranged on a post provided at the face of the internal combustion engine.

12. The belt drive according to claim 1, wherein the friction wheel comprises a spoked wheel formed of plastic, having a covering of a rubber material arranged on the outside circumference, and wherein the spoked wheel is urged against a bolt of the fork of the arm through an integrated and encapsulated rolling bearing.