HOLLOW ROTATING SHAFT COMPRISING A TUBULAR INSERT

Abstract

The invention relates to a rotary shaft extending in a longitudinal direction (R) and comprising an external surface (3d), this rotary shaft further comprising a hollow cylindrical part (3e) comprising an internal surface (3f), a first orifice (3g) arranged from the external surface (3d) to the hollow part (3e) and intended for the entry of a lubricant into this hollow part (3e), a second orifice (3h) arranged from the external surface (3d) to the hollow part (3e) and intended for the evacuation of the lubricant from the hollow part (3e), characterized in that the rotary shaft further comprises a ring (6) comprising a tubular wall (6a), the tubular wall (6a) comprising a hole (6b) for calibrating the flow rate of lubricant and a slot (6c), the ring (6) being inserted into the hollow part (3e) so as to present the calibration hole (6b) opposite the first orifice (3g) and the slot (6c) opposite the second orifice (3h),the slot (6c) forming with the internal surface (3f) a lubricant collection groove. Figure 2,

Description

Title of the invention: HOLLOW ROTARY SHAFT COMPRISING A TUBULAR INSERT

[0001] The present invention relates to the field of lubrication of the components of an internal combustion engine. More particularly, the invention relates to a hollow rotating shaft comprising a tubular insert.

[0002] In internal combustion engines equipped with camshafts, certain engine accessories may be driven by these camshafts. It is common to ensure the lubrication of such engine accessories by a lubricant mist in the environment of the contact between the camshaft cam and the engine accessory. Such an accessory may be, for example, a high-pressure fuel pump.

[0003] However, this lubrication generally proves to be insufficiently directed to satisfy the need for contact between the cam of the camshaft and the engine accessory.

[0004] Document EP2317083B1 also discloses a device for distributing lubricant through a bearing, but such a lubrication principle is difficult to implement and sensitive to the blockage of the oil passage channel in the bearing.

[0005] The invention aims to solve these drawbacks. To achieve this objective, the invention provides a rotary shaft extending in a longitudinal direction and comprising an external surface, this rotary shaft further comprising: - a hollow cylindrical part having an internal surface, - a first orifice arranged on the external surface of the hollow part and intended for the entry of a lubricant into this hollow part, - a second orifice arranged on the external surface of the hollow part and intended for the evacuation of lubricant from the hollow part, characterized in that the rotating shaft further comprises: - a ring comprising a tubular wall, the tubular wall comprising a lubricant flow calibration hole and a slot, the ring being inserted into the hollow part so as to present the calibration hole opposite the first orifice and the slot opposite the second orifice, the slot forming with the internal surface a lubricant collection groove.

[0006] The technical effect is to be able to bring lubricant to a determined point with a calibrated flow rate without having to carry out a delicate operation of machining a calibration hole on the rotating shaft.

[0007] Various additional features may be provided, alone or in combination:

[0008] In one embodiment, the diameter of the calibration hole is less than the diameter of the first lubricant inlet port.

[0009] In one embodiment, the ring is formed from an elastically deformable rolled metal sheet.

[0010] In one embodiment, the calibration hole is a punched hole.

[0011] In one embodiment, the hollow portion opens onto one end of this shaft. and is made blind by a stopper.

[0012] In one embodiment, the slot opens onto this end of the shaft.

[0013] The invention also relates to a mechanical assembly characterized in that it comprises a rotary shaft according to any one of the variants previously described, a bearing for supporting and guiding the rotation of the rotary shaft, this bearing comprising a lubricant supply pipe having an outlet opening onto the external surface of the rotary shaft, the bearing being arranged relative to the rotary shaft so that during its rotation the first orifice passes opposite the outlet of the lubricant supply pipe.

[0014] In one embodiment, the rotary shaft of the mechanical assembly comprises a control cam of an actuator, the second orifice being arranged at the foot of this cam.

[0015] The invention also relates to an internal combustion engine, characterized in that it comprises a mechanical assembly according to one of the variants previously described.

[0016] The invention also relates to a motor vehicle comprising such an internal combustion engine.

[0017] Other features and advantages will appear on reading the following description of a particular, non-limiting embodiment of the invention, given with reference to the figures in which:

[0018] [Fig.l]: this figure schematically represents a motor vehicle comprising a thermal engine equipped with a camshaft.

[0019] [Fig.2]: this figure represents in section passing through its axis of rotation a shaft with cam according to the invention.

[0020] [Fig.3]: this figure represents in cross section along plane AA of the camshaft of [Fig.2].

[0021] [Fig.l] shows a motor vehicle 1 comprising an internal combustion engine 2 equipped with a camshaft 3. This camshaft 3 is arranged to control mechanical actuators such as valves, rocker arms, pistons, or others.

[0022] [Fig. 2] shows in cross-section one end of the camshaft 3. This camshaft 3 comprises a shaft 3a. The camshaft 3 extends in a longitudinal direction along an axis of rotation R and is guided in rotation about this axis of rotation R by at least one support bearing 4.

[0023] In this embodiment, the camshaft 3 can carry at least one cam 3b for controlling a valve of the internal combustion engine 2. The camshaft 3 also carries at its end a cam 3c for controlling an actuator 5 according to a radial movement in a direction perpendicular to the axis of rotation R. The actuator 5 may be, for example, a fuel pump pusher of the internal combustion engine 2.

[0024] The shaft 3a of the camshaft 3 comprises an external surface 3d. The shaft 3a further comprises a hollow cylindrical part 3e. In this embodiment, the hollow part 3e opens onto one end of the shaft 3a and is made blind by a plug 7. The shaft 3a is therefore empty inside this hollow cylindrical part 3e resembling a tube, delimited by an internal surface 3f and the plug 7.

[0025] On the part of the shaft 3a between this end and the plug 7, the shaft 3a comprises a first orifice 3g pierced from the external surface to the hollow part 3e. This first orifice 3g is an inlet orifice for the lubricant in the hollow part 3e of the shaft 3a.

[0026] In this embodiment, the bearing 4 for supporting and guiding the rotation of the shaft 3a comprises a lubricant supply pipe 4a comprising an outlet opening onto the external surface 3d of the camshaft 3. In order to be able to transfer the lubricant from the bearing 4 to the hollow part 3e of the shaft 3a, the support bearing 4 is arranged relative to the shaft 3a so that during its rotation the first orifice 3g passes opposite the outlet of the lubricant supply pipe 4a.

[0027] The shaft 3a comprises a second orifice 3h pierced from the external surface 3d to the hollow part 3e. This second orifice 3h is an orifice for discharging the lubricant present in the hollow part 3e. This second evacuation orifice 3h is located in the immediate vicinity of the control cam 3c of the actuator 5, in other words at the foot of a flank of this cam 3c of the actuator 5.

[0028] The shaft 3a further comprises a ring 6 comprising a tubular wall 6a. This tubular wall 6a has on the one hand a hole 6b for calibrating the lubricant flow rate and on the other hand a slot 6c for collecting lubricant. The ring is inserted into the hollow part 3e so as to have the calibration hole 6b opposite the first orifice 3g and the slot 6c for collecting lubricant opposite the second orifice 3h.

[0029] In operation, when the camshaft 3 is rotating and there is oil pressure in the system, the lubricant supplied by the bearing 4 enters through the first orifice 3g. The lubricant then passes through the smaller calibrated hole 6b. By the centrifugal effect, the lubricant then spreads inside the ring 6 and is collected by the groove formed by the slot 6C of the ring 6 with the internal surface 3f. The groove guides the collected lubricant towards the second orifice 3h and the end of the shaft 3a. The second orifice 3h being at the foot of the cam 3c, the lubricant then rises by capillarity and centrifugal effect along the flank of the cam 3c, towards the actuator 5.

[0030] It is also possible to provide that the collection slot 6c of the ring 6 opens onto the end of the shaft 3a. In this case, a portion of the lubricant collected by the groove can flow to the end of the shaft 3a and be distributed by centrifugal effect along the flank of the cam 3c, towards the actuator 5.

[0031] The diameter of the first orifice 3g arranged in the shaft 3a is greater than that of the calibration hole 6b of the ring 6. Thus, it is the diameter of the calibration hole 6b which, by acting as a flow reducer, calibrates and controls the flow of lubricant entering the hollow part 3e. The fact of having the calibration hole 6b arranged in the ring 6 and not on the shaft 3a allows easier adaptation when developing the calibration of the desired flow of lubricant, since in this case only the hole in the ring needs to be modified, the shaft not being impacted in its design. For example, a diameter of the calibration hole 6b less than 1 mm can be provided if the inlet orifice 3g has a diameter between 2 and 3 mm. The diameter of the calibration hole 6b is chosen according to the desired flow of lubricant.

[0032] As illustrated in [Fig.3], the calibration hole can be placed at 180° from the collection slot 6c. The calibration hole can be obtained by punching for its profile and hole diameter.

[0033] It is possible to provide for a ring 6 to be made of sheet metal, for example of rolled steel, rolled with non-joined ends. This tube being elastically deformable, it acts like a spring and will be held in place with its radial force which provides a pressing force against the internal surface 3f of the shaft 3a. Thus, this ring 6 of metal tube, by its elasticity, avoids having to be fixed in the hollow part 3e of the shaft 3a by welding or with additional glue or a fixing element.

[0034] The invention is not limited to the embodiment described. Alternatively, the shaft may be a rotating shaft other than a camshaft, such as a crankshaft. The ring could be made from plastic materials depending on their characteristics in terms of oil resistance, elasticity and thickness.

[0035] The invention makes it possible to supply, without requiring the manufacture of a complex oil circuit, lubricant to a determined point along the camshaft, which without the invention would be an insufficiently lubricated zone.

[0036] The invention makes it possible to precisely regulate and control the radial flow of the lubricant, in particular the oil, directed towards the area to be lubricated, and thus to increase the service life of the device located in the area to be lubricated.

[0037] The invention avoids having to drill a very small hole in the wall of the tree because such drilling presents feasibility difficulties.

Claims

Claims

1. A rotary shaft extending in a longitudinal direction (R) and comprising an outer surface (3d), this rotary shaft further comprising: - a hollow cylindrical part (3e) having an inner surface (3f), - a first orifice (3g) arranged from the outer surface (3d) to the hollow part (3e) and intended for the entry of a lubricant into this hollow part (3e), - a second orifice (3h) arranged from the outer surface (3d) to the hollow part (3e) and intended for the evacuation of the lubricant from the hollow part (3e), characterized in that the rotary shaft further comprises: - a ring (6) comprising a tubular wall (6a), the tubular wall (6a) comprising a hole (6b) for calibrating the flow rate of lubricant and a slot (6c), the ring (6) being inserted into the hollow part (3e) so as to present the calibration hole (6b) opposite the first orifice (3g) and the slot (6c) opposite the second orifice (3h),the slot (6c) forming with the internal surface (3f) a lubricant collection groove.,

2. A rotary shaft according to claim 1, characterized in that the diameter of the calibration hole (6b) is smaller than the diameter of the first lubricant inlet orifice (3g).

3. A rotary shaft according to claim 1 or claim 2, characterized in that the ring (6) is formed from an elastically deformable rolled metal sheet.

4. A rotary shaft according to claim 3, characterized in that the calibration hole (6b) is a punched hole.

5. Rotary shaft according to one of the preceding claims, characterized in that the hollow part (3e) opens onto one end of this shaft and is made blind by a plug (7).

6. Rotary shaft according to claim 5, characterized in that the slot (6c) opens onto this end of the shaft.

7. Mechanical assembly characterized in that it comprises: - a rotary shaft according to any one of the preceding claims, - a bearing (4) for supporting and guiding the rotary shaft in rotation, this bearing (4) comprising a lubricant supply pipe (4a) having an outlet opening onto the external surface (3d) of the rotary shaft, the bearing (4) being arranged relative to the rotary shaft so that during its rotation the first orifice (3g) passes opposite the outlet of the lubricant supply pipe (4).

8. Mechanical assembly according to the preceding claim, characterized in that the rotary shaft comprises a cam (3c) for controlling an actuator (5), the second orifice (3h) being arranged at the foot of this cam (3c).

9. Internal combustion engine (2), characterized in that it comprises a mechanical assembly according to claim 7 or claim 8.

10. Motor vehicle (1), characterized in that it comprises an internal combustion engine (2) according to the preceding claim.

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