Camshaft device for an internal combustion engine having a variable distribution

Claim 2

In a camshaft device for an internal combustion engine having a variable distribution comprising means defining a fixed structure, a camshaft rotatably and axially slidably mounted relative to the structure, a fixed cylinder, a piston slidable in the fixed cylinder and defining with the cylinder a chamber, passage means including a constricted orifice for putting the chamber in communication with lubricating oil of the engine, an oil pressure modulator comprising a member defining an oil discharge orifice and a slide valve cooperative with the member to mask the discharge orifice to an extent which varies with the position of the slide valve relative to the member; and passage means putting the chamber in communication with the discharge orifice; the provision of a pressure responsive capsule having a movable diaphragm which is connected to shift the slide valve relative to the member of the modulator, a first source of pressure representing the load of the engine, a second source of pressure representing the speed of the engine and passage means putting the interior of the capsule in communication with the first and second sources of pressure.

Claim 3

A device as claimed in claim 1, wherein said first source is constituted by the induction pipe of the engine.

Claim 4

A device as claimed in claim 1, wherein said second source is constituted by the suction side of a vacuum pump driven by the engine.

Claim 5

A device as claimed in claim 3, wherein the induction pipe of the engine and the suction side of the pump are connected to the same chamber of the capsule.

Claim 6

A device as claimed in claim 2, wherein the suction take off on the induction pipe is disposed in such manner as to be closed when the throttle is closed and to be downstream of the throttle when the throttle opens.

Claim 7

A device as claimed in claim 1, wherein a calibrated orifice and a check valve are disposed in the passage means which connect the first source to the interior of the capsule.

Claim 8

In a camshaft device for an internal combustion engine having a variable distribution comprising means defining a fixed structure, a camshaft rotatably and axially slidably mounted relative to the structure, a fixed cylinder, a piston slidable in the fixed cylinder and defining with the cylinder a chamber, passage means including a constricted orifice for putting the chamber in communication with lubricating oil of the engine, an oil pressure modulator comprising a member defining an oil discharge orifice and a slide valve cooperative with the member to mask the discharge orifice to an extent which varies with the position of the slide valve relative to the member; and passage means putting the chamber in communication with the discharge orifice; the provision of a pressure responsive capsule having a movable disphragm which is connected to shift the slide valve relative to the member of the modulator, a first source of pressure representing the load of the engine, a second source of pressure representing the speed of the engine, passage means putting the interior of the capsule in communication with the first and second sources of pressure, a driven pinion slidably mounted on the camshaft, a ring integral with the camshaft, means carried by the ring and defining a cavity having a low coefficient of friction and an axis parallel to the camshaft, and an elongate member integral with the drive pinion and having an axis parallel to the camshaft and guided in the cavity.

Claim 9

In a camshaft device for an internal combustion engine having a variable distribution comprising means defining a fixed structure, a camshaft rotatably and axially slidably mounted relative to the structure, a fixed cylinder, a piston slidable in the fixed cylinder and defining with the cylinder a chamber, passage means including a constricted orifice for putting the chamber in communication with lubricating oil of the engine, an oil pressure modulator comprising a member defining an oil discharge orifice and a slide valve cooperative with the member to mask the discharge orifice to an extent which varies with the position of the slide valve relative to the member; and passage means putting the chamber in communication with the discharge orifice; the provision of a pressure responsive capsule having a movable disphragm which is connected to shift the slide valve relative to the member of the modulator, a first source of pressure representing the load of the engine, a second source of pressure representing the speed of the engine, passage means putting the interior of the capsule in communication with the first and second sources of pressure, a driven pinion slidably mounted on the camshaft, a ring integral with the camshaft, means carried by the ring and defining a cavity having a low coefficient of friction and an axis parallel to the camshaft, and an elongate member integral with the drive pinion and having an axis parallel to the camshaft and guided in the cavity.

Claim 10

A device as claimed in claim 7, wherein there are provided a plurality of said cavities evenly spaced apart around the camshaft and a plurality of said elongate members guided in said cavities.

Claim 11

A device as claimed in claim 7, wherein said cavity comprises longitudinal raceway means and balls combined with the raceways and rollingly engaging the elongate member.

Claim 12

A device as claimed in claim 7, wherein elastically yieldable means are interposed between the ring and the pinion and acts to bias the ring and pinion apart.