FR2663683A1 - SYSTEM FOR LUBRICATING SURFACES IN CONTACT WITH A CAMSHAFT AND A HYDRAULIC TAPPET FOR AN INTERNAL COMBUSTION ENGINE. - Google Patents

Abstract

This lubrication system, in which the pusher (2) comprises a jacket (15) comprising a first hydraulic compression chamber (20) for adjusting the clearance of a corresponding valve, supplied from a source of fluid through at least a first orifice (18) formed in the side wall of the sleeve (15), when the pusher is in the high position, is characterized in that the sleeve (15) comprises a second hydraulic chamber (21), above from the first, at least a second orifice (23) opening into the second chamber (21), formed in its side wall above the first, at a distance corresponding to the stroke of the pusher, so that the second chamber (21) or supplied from the source when the pusher is in the low position and at least one third orifice (25) formed in its upper wall; opening out on the one hand into the second chamber (21) and on the other hand near the contacting surfaces of the camshaft and the tappet in order to lubricate them.

Description

I The present invention relates to a surface lubrication system

  in contact with a camshaft and a hydraulic tappet for an internal combustion engine. These pushers generally include a shirt

  comprising a first hydraulic compression chamber

  for adjusting the clearance of a corresponding valve

  te, this chamber being supplied from a source of fluid through a first orifice formed in the side wall of the jacket, when the pusher is in

high position.

  In internal combustion engines, in which the valves are actuated by hydraulic tappets, it is necessary to lubricate the

  surfaces in contact with the camshaft and the tappet.

  For this, an oil bath is created in the bottom of the cylinder head of the engine, this oil bath also making it possible to remove the calories released by the friction of the

moving parts.

  To feed this oil bath we currently use-

  either a lubrication ramp provided in the cylinder head cover or attached to it, or a supply channel for the hydraulic tappets with pressurized fluid, provided in the cylinder head, by making holes in this cylinder head opening out on the one hand in this

  channel and secondly, at the level of the cams.

  However, these different solutions have a

  number of drawbacks Indeed they require

  try additional parts or machining Furthermore, the fluid flow is permanent so that there can be an overabundance of fluid in the bottom of the cylinder head which requires to evacuate the overflow to

  the oil tank located at the bottom of the engine.

  The object of the invention is therefore to solve these problems by proposing a system for lubricating the surfaces in contact with the camshaft and the hydraulic tappet which is simple, reliable and which avoids any machining or addition of additional parts in the

cylinder head-

  To this end the invention relates to a system for lubricating the surfaces in contact with a camshaft and a hydraulic tappet for an internal combustion engine, in which the tappet comprises a jacket

  comprising a first hydraulic compression chamber

  for adjusting the clearance of a corresponding valve

  te, supplied from a source of fluid through at least a first orifice formed in the side wall of the jacket, when the pusher is in the high position, characterized in that the jacket comprises a second hydraulic chamber, above from the first, at least one second orifice opening into the second chamber, formed in its side wall above the first, at a distance corresponding to the stroke of the pusher, so that the second chamber is supplied from the source when the plunger is in the low position, and at least a third orifice formed in its upper wall, opening on the one hand into the second chamber and on the other hand near the surfaces in contact with the camshaft and the plunger

to lubricate them.

  The invention will be better understood using the

  description which will follow given only as a

  example and made with reference to the accompanying drawings in which: FIG. 1 is a sectional view of part of an internal combustion engine illustrating different lubrication systems of a camshaft and a tappet, state of the art; Figure 2 is a partial sectional view of a hydraulic pusher of the prior art; Figure 3 is a partial sectional view of a hydraulic tappet forming part of a lubrication system according to the invention; and Figures 4 and 5 illustrate the operation of a lubrication system according to the invention. As can be seen in Figure 1, and as already mentioned, to supply the oil bath created in the bottom of the cylinder head to lubricate the contact surfaces of a camshaft 1 and a hydraulic tappet 2, in the state of the art, either a lubrication ramp 3 made in the cylinder head cover 4 or attached to it, or the channel 5 for supplying the hydraulic tappets with pressurized fluid, making holes in the cylinder head 6 One end of these holes opens into this channel and the other, at the level of the cams As mentioned previously, these different solutions have a certain number of drawbacks

who will not be called back.

  The hydraulic tappets 2 of the prior art, one of which is shown in FIG. 2, comprise a jacket 8 and a piston assembly 9

  used to adjust the clearance of a corresponding valve.

  An annular spacer 10 disposed between the piston assembly 9 and the side wall of the jacket 8, delimits an annular chamber 11 intended to contain the hydraulic fluid necessary for the operation of the plunger This fluid is introduced into this chamber by means of a groove annular 12 formed in the outer surface of the side wall of the jacket, and an orifice 13 opening on the one hand into the chamber 11 and on the other hand into the groove 12, from the supply channel 5

described with reference to Figure 1-

  An orifice 14 (Figure 1), one end of which opens into this channel 5, is also provided in the cylinder head, to supply this chamber with fluid when

the pusher is in the high position.

  If we now refer to Figure 3 which is

  a sectional view of a pusher entering the constituent

  tion of a lubrication system according to the invention, it can be seen that it has the same elements as those described with reference to FIG. 2, namely a jacket 15, a piston assembly 16, a first annular spacer 17 between the side wall of the jacket and the piston assembly, a first orifice 18 opening into a first annular groove 19 for supplying a first chamber 20 of fluid

  necessary for the operation of the piston assembly.

  According to the invention, the shirt 15 comprises a second

  hydraulic chamber 21 formed above the first.

  The first and second hydraulic chambers of this jacket are separated by an annular spacer 22 one end of which is fixed to the interior surface of the side wall of the jacket 15 and the other to the interior surface of the top wall of this jacket. This jacket also has at least a second orifice 23 opening into this second chamber 21, this orifice being formed in the side wall of the shirt, above the first orifice 18 at a distance corresponding to the stroke of the pusher so that the second chamber 21 is supplied from the source when the pusher is in the low position, as will be described in more detail below This orifice also opens into a parallel annular groove 24

  throat 19 described above.

  The jacket also comprises at least a third calibrated orifice 25 formed in its upper wall, this orifice opening on the one hand into the second chamber 21 and on the other hand near the surfaces in contact with

  the camshaft and the tappet to lubricate them.

  It should be noted that the annular spacers 17 and 22 can be fixed in any suitable manner in the jacket, for example by crimping or welding by electronic bombardment. As can be seen in Figure 4, when the

  pusher 2 is in the high position, the supply duct

  tion 5 and the orifice 14 opening into the latter are opposite the orifice 18 formed in the side wall of the jacket 15, this orifice opening into the chamber 20 of pressurized fluid necessary for adjusting the clearance of a corresponding valve On the other hand if the pusher is in the low position (FIG. 5) the fluid supply channel 5 and the orifice 14 opening out

  in this one, are facing the supply duct 23

  tion of the second chamber 21 Thus in this position of the pusher the source of fluid feeds this second chamber 21, the pressurized fluid escaping from this chamber through the orifice 25 formed in the upper wall of the jacket near the surfaces in contact of

  the camshaft and the tappet, to lubricate them

  ci The orientation and dimension of this orifice 25 can be determined to precisely direct a certain quantity of fluid on the facing surfaces

  to obtain optimal lubrication.

  It is thus possible to control the flow of lubrication fluid towards these surfaces insofar as this flow takes place in each chamber only during part of the working time This structure makes it possible to avoid any machining or addition of

  additional parts in the cylinder head or cover

  cylinder head and requires only a minor modification of the pusher. It goes without saying of course that other embodiments can be envisaged. For example, the annular groove 24 (FIG. 3) may have several orifices spaced around its periphery to improve the filling of the second chamber. Similarly, several orifices oriented so different can be provided in the upper wall of the tappet to ensure the simultaneous lubrication of several elements for example in the case of engines having twin camshafts or valve controls by devices

combined cams / latches.

Claims (4)

  1 system for lubricating the surfaces in contact with a camshaft and a hydraulic tappet for an internal combustion engine, in which the tappet (2) comprises a jacket (15) comprising a first hydraulic compression chamber (20) for adjusting the clearance of a corresponding valve, supplied from a source of fluid (5) through at least one first orifice (18) formed in the side wall of the jacket (15), when the pusher is in high position, characterized in that the jacket (15) comprises a second hydraulic chamber (21), above the first, at least one second orifice (23) opening into the second chamber (21), formed in its wall   lateral above the first at a corresponding distance   during the stroke of the pusher, so that the second chamber (21) is supplied from the source (5) when the pusher is in the low position and at least one third orifice (25) formed in its upper wall, opening out on the one hand in the second chamber (21) and on the other hand near the surfaces in contact with   the camshaft and the tappet to lubricate them.   2 lubrication system according to claim 1, characterized in that the second orifice (23) opens into an annular groove (24) formed in the surface   outside of the side wall of the jacket (15).   3 Lubrication system according to the claims   1 or 2, characterized in that the first and second chambers (20, 21) of the jacket (15) are separated by an annular spacer (22), one end of which is fixed to the inner surface of the side wall of the jacket (15) and the other on the   inner surface of the upper wall of the shirt.   4 Lubrication system according to any one   of the preceding claims, characterized in that   several orifices of different orientation   formed in the upper wall of the shirt. are