HOLLOW ROTATING SHAFT INCLUDING A TUBULAR INSERT

Abstract

The invention relates to a rotating shaft extending along a longitudinal direction (R) and comprising an external surface (3d), this rotating shaft further comprising a hollow cylindrical part (3e) having an internal surface (3f), a first orifice (3g) provided 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) provided 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 rotating shaft further comprises a ring (6) comprising a tubular wall (6a), the tubular wall (6a) comprising a hole (6b) for calibrating the lubricant flow and a slot (6c), the ring (6) being inserted in 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) forms a lubricant collection groove with the internal surface (3f). Figure 2,

Description

Title of the invention: HOLLOW ROTATING 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 practice to lubricate such engine accessories by means of a lubricant mist in the contact area between the camshaft lobe and the engine accessory. Such an accessory could be, for example, a high-pressure fuel pump.

[0003] However, this lubrication generally proves to be insufficiently directed to meet the needs of the contacts between the camshaft and the engine accessory.

[0004] A lubricant distribution device through a bearing is also known from document EP2317083B1, but such a lubrication principle is difficult to implement and sensitive to blockage of the oil passage channel in the bearing.

[0005] The invention aims to overcome these drawbacks. To achieve this objective, the invention provides a rotating shaft extending along a longitudinal direction and comprising an external surface, this rotating shaft further comprising: - a hollow cylindrical part comprising an internal surface, - a first opening formed on the external surface of the hollow part and intended for the entry of a lubricant into this hollow part, -a second opening provided on the external surface to 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 machining operation of 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 diameter of the first lubricant inlet orifice.

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

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

[0011] In one embodiment, the hollow part opens onto one end of this tree and is blinded by a plug.

[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 rotating shaft according to any of the variants previously described, a bearing for supporting and guiding the rotation of the rotating shaft, this bearing comprising a lubricant supply line having an outlet opening onto the external surface of the rotating shaft, the bearing being arranged relative to the rotating shaft so that during its rotation the first orifice passes opposite the outlet of the lubricant supply line.

[0014] In one embodiment, the rotating shaft of the mechanical assembly includes a control cam for an actuator, the second orifice being provided at the base 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 become apparent from the following description of a particular, non-limiting embodiment of the invention, made with reference to the figures in which:

[0018] [Fig.1]: This figure schematically represents a motor vehicle comprising a thermal engine equipped with a camshaft.

[0019] [Fig.2]: This figure represents a cross-section through its axis of rotation of a shaft came in accordance with the invention.

[0020] [Fig.3]: This figure represents a cross-section of the camshaft of [Fig.2] along plane AA.

[0021] Fig. 1 presents 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] Figure 2 shows a cross-sectional view of 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 the control of a valve of the internal combustion engine 2. The camshaft 3 also carries at its end a cam 3c for the control of an actuator 5 according to a radial movement in a direction perpendicular to the axis of rotation R. The actuator 5 can be, for example, a fuel pump pusher from the internal combustion engine 2.

[0024] The camshaft 3 includes an external surface 3d. The shaft 3a further includes a hollow cylindrical portion 3e. In this embodiment, the hollow portion 3e opens onto one end of the shaft 3a and is blinded by a plug 7. The shaft 3a is therefore hollow inside this tube-like hollow cylindrical portion 3e, delimited by an internal surface 3f and the plug 7.

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

[0026] In this embodiment, the bearing 4 for supporting and guiding the rotation of the shaft 3a includes a lubricant supply line 4a having 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 line 4a.

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

[0028] The shaft 3a further includes a ring 6 having a tubular wall 6a. This tubular wall 6a has, on one side, a orifice 6b for calibrating the lubricant flow and, on the other side, a slot 6c for collecting lubricant. The ring is inserted into the hollow portion 3e so as to present the calibration hole 6b opposite the first orifice 3g and the lubricant collection slot 6c opposite the second orifice 3h.

[0029] During 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 orifice 6b. By centrifugal force, 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 inner surface 3f. The groove guides the collected lubricant towards the second orifice 3h and the end of the shaft 3a. Since the second orifice 3h is located at the base of the cam 3c, the lubricant then rises by capillary action and centrifugal force along the flank of the cam 3c, towards the actuator 5.

[0030] It can also be provided that the collection slot 6c of the ring 6 opens onto the end of the shaft 3a. In this case, part 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 in the shaft 3a is larger than that of the calibration hole 6b in the ring 6. Thus, it is the diameter of the calibration hole 6b which, acting as a flow restrictor, calibrates and controls the flow of lubricant entering the hollow section 3e. Having the calibration hole 6b located in the ring 6, rather than on the shaft 3a, allows for easier adjustment when fine-tuning the calibration of the desired lubricant flow rate, since in this case only the hole in the ring needs to be modified, the shaft's design remaining unchanged. For example, a diameter of the calibration hole 6b of less than 1 mm can be used 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 lubricant flow rate.

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

[0033] A ring 6 can be made of sheet metal, for example rolled steel, with unjoined ends. Since this tube is elastically deformable, it acts like a spring and will be held in place by its radial force, which exerts a pressing force against the internal surface 3f of the shaft 3a. Thus, this metal tube ring 6, by virtue of its elasticity, avoids the need to be fixed in the hollow part 3e of the shaft 3a by welding, with additional adhesive, or with a fastener.

[0034] The invention is not limited to the embodiment described. Alternatively, the shaft may be a rotating shaft other than a camshaft, for example a crankshaft. The bushing 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 bring lubricant to a specific point along the camshaft, which without the invention would be an insufficiently lubricated area, without the need for the manufacture of a complex oil circuit.

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

Demands

1. A rotating shaft extending along a longitudinal direction (R) and comprising an external surface (3d), this rotating shaft further comprising: - a hollow cylindrical portion (3e) having an internal surface (3f), - a first orifice (3g) provided from the external surface (3d) to the hollow portion (3e) and intended for the entry of a lubricant into this hollow portion (3e), - a second orifice (3h) provided from the external surface (3d) to the hollow portion (3e) and intended for the discharge of the lubricant from the hollow portion (3e), characterized in that the rotating shaft further comprises: - a ring (6) comprising a tubular wall (6a), the tubular wall (6a) comprising a lubricant flow calibration hole (6b) and a slot (6c), the ring (6) being inserted into the hollow portion (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 groove for collecting the lubricant.

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

3. Rotating shaft according to claim 1 or claim 2, characterized in that the ring (6) is formed of a rolled, elastically deformable sheet metal.

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

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

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

8. Mechanical assembly according to the preceding claim, characterized in that the rotating shaft includes a cam (3c) for controlling an actuator (5), the second orifice (3h) being provided at the base 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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