GB2545410A

GB2545410A - Tensioner for an endless drive element of an internal combustion engine

Info

Publication number: GB2545410A
Application number: GB1521846.4A
Authority: GB
Inventors: Andreas Braun Florian; J Hazelton Gary; Wilms Carsten
Original assignee: GM Global Technology Operations LLC
Current assignee: GM Global Technology Operations LLC
Priority date: 2015-12-10
Filing date: 2015-12-10
Publication date: 2017-06-21
Also published as: GB201521846D0

Abstract

A tensioner (500 in Fig. 2) for an endless drive element (600 in Fig. 2) of an internal combustion engine (110 in Fig. 1) is provided. The tensioner comprises a support body 580 and a tensioning element 510. The support body 580 comprises: a hollow housing 580a; an oil chamber 590; a feeding duct 586 connecting the hollow housing 580a to the oil chamber 590. The tensioning element 510 is at least partially inserted within the hollow housing 580a in a movable manner with respect to the support body 580. An elastic element 520 biases the movable tensioning element 510 for imparting tension to the endless drive element. The oil chamber 590 further comprises a chamber oil inlet 595 to fluidly connect the oil chamber 590 to an oil supply line 700 of the internal combustion engine. The chamber oil inlet 595 is arranged at a level above the feeding duct 586 to retain oil within the hollow housing 580a and the oil chamber 590.

Description

TENSIONER FOR AN ENDLESS DRIVE ELEMENT OF AN INTERNAL COMBUSTION

ENGINE

TECHNICAL FIELD

The technical field relates to a tensioner, also known as tensioning device, for imparting tension to an endless drive element of an internal combustion engine, such as a chain or a belt. It has to be noted that the expression “endless drive element’ is used herein to indicate a loop-shaped flexible element used in the internal combustion engine for torque/power transmission, for example between two rotatable shafts thereof, e.g. the crankshaft and the camshaft.

BACKGROUND

It is known that internal combustion engines are provided with a timing chain or timing belt (also known as drive chain or drive belt) that synchronizes the rotation of the crankshaft and the camshafts) so that the engine's valves open and close at the proper times during each cylinder's intake and exhaust strokes.

The timing chain is typically a roller, bushing or inverted tooth (IT) chain, and a timing belt is typically a toothed belt made of rubber material reinforced with fibers or similar components. The timing chain/belt connects a crankshaft sprocket (i.e. a drive wheel), a camshaft sprocket (i.e. a driven wheel) and eventually other component like a

Fuel Injection Pump.

Belts can be also used in the internal combustion engine to drive accessories, such as an alternator, the water pump, the air conditioning compressor, etc.. For this purpose, a so-called accessory belt is used to connect a rotatable shaft of the engine, e.g. the crankshaft, with said accessories.

The timing chain/belt and also the accessory belt used in internal combustion engine are guided along a predetermined path by means of chain/belt guides comprising a guide member, e.g. a lever arm or a shoe or pulleys.

Additionally, providing the corrected tension of the endless drive element, e.g. of the chain/belt, is critical to provide a correct and effective operation of the internal combustion engine and in particular to prevent undesired noise, slippage, etc.

Tensioners (tensioning devices) are known in the art to adjusting the chain/belt tension during the engine functionality, thus compensating dynamics and recover elongation of the chain/belt occurring along engine life.

Tensioners typically comprise a plunger that is movable in a housing so as to be urged to protrude from the housing. A front surface of the plunger imparts tension to the chain by interposition of a movable chain guide member (also known as tensioner shoe) or similar element. The tensioner pushes the movable chain guide that, rotating around a pivot, abuts against the timing chain to obtain a proper chain tensioning and to recover the chain elongation.

The plunger is usually biased by a compression spring toward an extended position outwardly the housing and defines. The tensioner is connected to the internal combustion engine so that, in operative conditions, oil can flow from the internal combustion engine to the housing of the plunger. The oil provides a dampening effect for the plunger by means of oil flowing across calibrated openings.

During engine start-up, and in particular after long or short duration shutdowns which allow the oil to drain from the tensioner, the oil may take some time before reaching the tensioner, so that an undesired rattle noise may be produced by the system. In particular, in these operating conditions the movable plunger is moved in reverse direction, i.e. inside the housing, away from the chain, and overcomes the biasing effect of the spring, thus reaching a contact with a surface inside the housing. In other words, the plunger contacts a surface inside the housing, thus causing an undesired rattle noise. The chain might also rattle against the tensioner guide due to lack of control, or it could even skip a timing tooth causing an engine failure.

To prevent such occurrence, a possible solution is to increase stiffness of the spring so as to prevent rattle noise in the above mentioned operating conditions.

However, an increased stiffness of the spring that biases the plunger, leads to an undesired wining noise due to a higher load of the chain.

Otherwise, the tensioner may be provided with a ratchet to prevent the plunger from reaching the above mentioned end stop. This solution is effective, but at the same time is costly and complex.

An object of an embodiment disclosed is to overcome the above mentioned issues, and in particular to prevent rattle noise due to the undesired contact between the tensioning element, e.g. the plunger, with a surface inside the housing, and also to prevent chain rattle against the tensioner guide(s) and engine failure concerns during some engine operating conditions and during startup.

An object of an embodiment disclosed is to overcome the above mentioned undesired effects, with a cost effective solution which also does not increase complexity of the tensioner.

This and other objects are achieved by the embodiment of the invention as defined in the independent claim. The dependent claims include preferred and/or advantageous aspects of said embodiment.

SUMMARY

An embodiment of the disclosure provides a tensioner for an endless drive element of an internal combustion engine, the tensioner comprising a support body and a tensioning element, the support body comprising a hollow housing, an oil chamber, a feeding duct connecting the hollow housing to the oil chamber, wherein the tensioning element is at least partially inserted within the hollow housing in a movable manner with respect to said support body, an elastic element biases said movable tensioning element for imparting tension to said endless drive element, the oil chamber further comprising a chamber oil inlet to fluidly connect the oil chamber to an oil supply line of the internal combustion engine, wherein the chamber oil inlet is arranged at a level above the feeding duct to retain a quantity of oil within said hollow housing and said oil chamber.

It has to be noted that the reference to a level of the chamber oil inlet above the feeing duct is used herein to indicate that the chamber oil inlet is arranged at a higher position with respect to the feeding duct to retain oil within the hollow housing and the oil chamber, and thus to prevent oil draining under gravity from the oil chamber.

In other words, considering the different levels that can be reached by the free surface of the oil within the oil chamber, the chamber oil inlet is arranged at higher level (above) with respect to the level at which the feeding duct is arranged.

Thanks to the present embodiment, an amount of oil is retained within the hollow housing, i.e. within the seat wherein the tensioning element moves, in all the engine conditions, including also the condition in which the internal combustion engine is not operating at all. In more detail, considering e.g. when the internal combustion engine is turned off, the oil in the oil chamber starts flowing back to the internal combustion engine through the chamber oil inlet, until the free surface of oil is lowered at (i.e. just below) the level (height) of the chamber oil inlet itself. As the chamber oil inlet is placed at a level above the feeding duct, a certain amount of oil is also retained within the hollow housing, so as to always provide for the required dampening effect. Advantageously, the chamber oil inlet is at a level well above the feeding duct height to maintain oil in the oil chamber during all conditions and to prevent oil draining from the oil chamber, for example when oil is no longer supplied via the oil supply line during engine shutdowns.

Additionally, it has to be noted that even if reference to “oil” and “oil chamber” is made, it is understood that however other fluid may be used to dampen the motion of the tensioning element.

According to an embodiment the tensioner comprises one or more fastener to constrain the support body to an internal combustion engine, preferably to a correspondent engine connection portion. The tensioner is constrained to the internal combustion engine by means of one or more fastener to be oriented so that the chamber oil inlet is arranged at a level above the feeding duct, to retain oil within said hollow housing and said oil chamber.

Advantageously, the chamber oil inlet and the feeing duct are arranged so that, in use (when the tensioner is constrained to the internal combustion engine), the chamber oil inlet is at a higher position (level) with respect to the feeding duct to prevent oil draining under gravity from the oil chamber and thus to effectively retain an amount of oil within the hollow housing and the oil chamber. According to an embodiment, the % chamber oil inlet is arranged on a wall detachable from the support body.

Thanks to this, the detachable wall can be added to already existing configurations of tensioners, in an easy a simple manner, providing the above mentioned advantages.

According to an embodiment, said detachable wall is a gasket. This helps preventing leakages from the oil chamber around the sealing perimeter to the engine.

According to an embodiment, wherein said gasket is made of a material selected from rubber, plastic, metal, a, or combinations of the above. As an example, an effective solution provides for a layered gasket, having layers of different materials, e.g. a metal layer interposed between two rubber layers. This provides for a simple and cost-effective solution. As an example, according to an embodiment, said wall is a metallic plate. This provides for a particularly cost-effective. Sealing can be provided by the tight engagement between the support body and the metallic plate. In a different embodiment, as mentioned, a metallic layer can be covered by rubber layer(s) to provide effective sealing.

According to an embodiment, said wall is coupled to the external surface of the support body. In other words, a first portion of the wall closes the oil chamber and a second portion of the wall (arranged externally with respect to said first portion) is coupled to the support body.

According to an embodiment, the tensioning element comprises a plunger, movable in a reciprocating manner within the hollow housing. Furthermore, according to an embodiment, the tensioning element comprises a guide member to guide the endless drive element. These embodiments have proven to be particularly effective. A further embodiment further provides for an internal combustion engine comprising a tensioner according to any of the preceding aspects.

According to an embodiment, the internal combustion engine comprising a tensioner, wherein the tensioner is constrained to an engine connection portion at the oil supply line. The oil chamber of the tensioner is fluidically connected to the oil supply line of the internal combustion engine via the chamber oil inlet. Advantageously, as mentioned above, the chamber oil inlet is arranged at a higher position (level) with respect to the feeding duct to prevent oil draining under gravity from the oil chamber and thus to effectively retain an amount of oil within the hollow housing and the oil chamber, even if the oil supply line of the internal combustion engine is arranged a level below the chamber oil inlet.

According to an embodiment, the chamber oil inlet is arranged on a gasket interposed between an engine connection portion and the support body of the tensioner. This embodiment, allows providing the above mentioned advantages by using a gasket interposed between the tensioner and the portion of the internal combustion engine to which the support body of the tensioner is constrained.

BRIEF DESCRIPTION OF THE DRAWINGS

The various embodiments will now be described, by way of example, with reference to the accompanying drawings, wherein like numerals denote like elements, and in which:

Figure 1 shows an automotive system;

Figure 2 is a cross-section of an internal combustion engine belonging to the automotive system of figure 1;

Figure 3 is a schematic cross section Of a tensioner in a first engine operative condition, wherein oil is supplied to the tensioner;

Figure 4 is a schematic cross section of the tensioner of figure 3, in a second engine operative condition, wherein oil is not supplied to the tensioner;

Figure 5 is a perspective view of a tensioner according to an embodiment;

Figure 6 is a perspective view as per figure 5, without the detachable wall;

Figure 7 is schematic a lateral cross section of an embodiment of a tensioner;

Figure 8 is a schematic perspective view of a tensioner coupled to an endless drive element.

DETAILED DESCRIPTION

Exemplary embodiments will now be described with reference to the enclosed drawings without intent to limit application and uses.

Some embodiments may include an automotive system 100, as shown in Figures 1 and 2, that includes an internal combustion engine (ICE) 110 having an engine block 120 defining at least one cylinder 125 having a piston 140 coupled to rotate a crankshaft 145. A cylinder head 130 cooperates with the piston 140 to define a combustion chamber 150. A fuel and air mixture (not shown) is disposed in the combustion chamber 150 and ignited, resulting in hot expanding exhaust gasses causing reciprocal movement of the piston 140. The fuel is provided by at least one fuel injector 160 and the air through at least one intake port 210. The fuel is provided at high pressure to the fuel injector 160 from a fuel rail 170 in fluid communication with a high pressure fuel pump 180 that increases the pressure of the fuel received from a fuel source 190. Each of the cylinders 125 has at least two valves 215, actuated by a camshaft 135 rotating in time with the crankshaft 145, for example by means of an endless drive element, e.g. a timing chain 600.

More in details, according to a possible embodiment, the chain 600 connects the camshaft 135 and the crankshaft 145, as for example shown in figure 8. A camshaft sprocket 135a is attached to one end of the camshaft 135, and a crankshaft sprocket 145a is attached to one end of the crankshaft 145. A timing chain 600 connects the crankshaft sprocket 145a and the camshaft sprocket 135a so that the timing chain may transmit power from rotating crankshaft 145 to camshaft 135.

The valves 215 selectively allow air into the combustion chamber 150 from the port 210 and alternately allow exhaust gases to exit through a port 220. In some examples, a cam phaser 155 may selectively vary the timing between the camshaft 135 and the crankshaft 145.

The air may be distributed to the air intake port(s) 210 through an intake manifold 200. An air intake duct 205 may provide air from the ambient environment to the intake manifold 200.

In other embodiments, a throttle body 330 may be provided to regulate the flow of air into the manifold 200.

In still other embodiments, a forced air system such as a turbocharger 230, having a compressor 240 rotationally coupled to a turbine 250, may be provided. Rotation of the compressor 240 increases the pressure and temperature of the air in the duct 205 and manifold 200. An intercooler 260 disposed in the duct 205 may reduce the temperature of the air. The turbine 250 rotates by receiving exhaust gases from an exhaust manifold 225 that directs exhaust gases from the exhaust ports 220 and through a series of vanes prior to expansion through the turbine 250. The exhaust gases exit the turbine 250 and 111 and the support body 580. According to an embodiment, the tensioner 500 is coupled to the engine connection portion 111 by means of one or (preferably) more fastener(s) 800. In more details, fasteners pass through relevant openings of the support body 580 and the detachable wall 590a, and they can be fastened into relevant threaded holes of the engine connection portion 111, so as to force the tensioner 500 against the engine connection portion 111 itself.

In operation, the chain 600 is arranged in contact with the tensioner 500. In particular, the elastic element 520 biases the tensioning element 510 against the endless drive element, to tension it. Oil (typically oil under pressure) is supplied by the oil supply line 700 to the tensioner 500, and in particular to the hollow housing 580a. Movement of the tensioning element 510 is properly damped. This condition is shown in figure 3, the oil being represented by dots.

When the internal combustion engine is no longer active, or in general when oil pressure drops, oil chamber 590a begins to empty from oil (i.e. oil stars to flow out from the oil chamber 590 towards the engine bearing support 111 or other leakage path connected to supply line 700 through the chamber oil inlet 595). However, when the free surface of oil is lowered below the level of the chamber oil inlet 595, the oil chamber 590a stops to empty, so that a certain amount of oil is retained within the oil chamber 590. This condition is shown in figure 4, the oil being represented by dots.

As mentioned, the feeding duct 586 is below (i.e. it is at a lower level or position with respect to) the oil chamber inlet 595, so that a certain amount of oil remains also in the feeding duct, and thus into the hollow housing 580a, that is connected to the feeding duct 586. As a result, such an amount of oil guarantees the proper dampening to the movement of the tensioning element 510 even when oil is not (or not yet) fed by the supply line 700 to the tensioner 500, e.g. at the start-up of the internal combustion are directed into an exhaust system 270. This example shows a variable geometry turbine (VGT) with a VGT actuator 290 arranged to move the vanes to alter the flow of the exhaust gases through the turbine 250. In other embodiments, the turbocharger 230 may be fixed geometry and/or include a waste gate.

The exhaust gases of the engine are directed into an exhaust system 270.

The exhaust system 270 may include an exhaust pipe 275 having one or more exhaust aftertreatment devices 280. The aftertreatment devices may be any device configured to change the composition of the exhaust gases. Some examples of aftertreatment devices 280 include, but are not limited to, catalytic converters (two and three way), oxidation catalysts, lean NOx traps, hydrocarbon adsorbers, selective catalytic reduction (SCR) systems, and particulate filters. Other embodiments may include an exhaust gas recirculation (EGR) system 300 coupled between the exhaust manifold 225 and the intake manifold 200. The EGR system 300 may include an EGR cooler 310 to reduce the temperature of the exhaust gases in the EGR system 300. An EGR valve 320 regulates a flow of exhaust gases in the EGR system 300.

The automotive system 100 may further include an electronic control unit (ECU) 450 in communication with one or more sensors and/or devices associated with the ICE 110 and with a memory system, or data earner, and an interface bus.

The ECU 450 may receive input signals from various sensors configured to generate the signals in proportion to various physical parameters associated with the ICE 110. The sensors include, but are not limited to, a mass airflow and temperature sensor 340, a manifold pressure and temperature sensor 350, a combustion pressure sensor 360, coolant and oil temperature and level sensors 380, a fuel rail pressure sensor 400, a cam position sensor 410, a crank position sensor 420, exhaust pressure and temperature sensors 430, an EGR temperature sensor 440, and an accelerator pedal position sensor 445. Furthermore, the ECU 450 may generate output signals to various control devices that are arranged to control the operation of the ICE 110, including, but not limited to, the fuel injectors 160, the throttle body 330, the EGR Valve 320, a Variable Geometry Turbine (VGT) actuator 290, and the cam phaser 155. Note, dashed lines are used to indicate communication between the ECU 450 and the various sensors and devices, but some are omitted for clarity.

With reference to figures 3 - 8, possible embodiments of a tensioner 500 according to exemplary the invention will be now discussed.

The tensioner 500 for an endless drive element 600 of an internal combustion engine 110, comprises a support body 580 and a tensioning element 510, that is movable with respect to the support body 580. In particular, the support body 580 comprises a hollow housing 580a inside which the tensioning element 510 is arranged to move, typically by sliding therein. Such a movement is typically linear, i.e. it is a reciprocating motion.

In general, the tensioner 500 is movable towards and away from at least one tensioning position in which the tensioning element 510 is forced against the endless drive element 600 (from now on also referred as chain 600 for easiness of description).

The tensioner 500 further comprises an elastic element 520 biasing the movable tensioning element towards the above mentioned at least one tensioning position for imparting tension to said endless drive element 600. In particular, an elastic element 520 is preferably arranged within the hollow housing 580a, between the support body 580 and the tensioning element 510, so that the latter is able to impart tension to the chain 600. The elastic element 520 is typically embodied as a spring, preferably a compression spring. From now on, for easiness of description, reference to a spring 520 will be made. However, the following description applies as well to other elastic elements 520.

According to an embodiment, the tensioning element 510 is provided with a plunger 510a, that is movable along longitudinal direction, i.e. it is movable with a linear motion with respect to the support body 580 of the tensioner 500. This type of tensioner is typically used for tensioning a chain 600, e.g. a timing chain of an internal combustion engine.

More in detail, the plunger 510a is biased by means of a spring 520 in axial direction with respect to the hollow housing 580. The compression spring 520 is adapted to push the plunger 510a against a chain/belt 600. A guide member 510b, e.g. a tensioner shoe or similar component (as for example shown in figure 8) can be interposed between the plunger 510a and the chain 600.

The hollow housing 580a is at least partially filled with oil to provide the above mentioned dampening effect. In particular, the support body 580 is provided with an oil chamber 590, configured to receive oil from an oil supply line 700 of the internal combustion engine 110, and to deliver it to the hollow housing 580a. Typically the oil chamber 590 is arranged laterally with respect to hollow housing 580a, but other solutions are possible.

The oil chamber 590 is provided with a chamber oil inlet 595 that, in use, is connected to the oil supply line 700 of the internal combustion engine 110. Furthermore, a feeding duct 586 fluidly connects the oil chamber 590 to the hollow housing 580a. In more detail, the hollow housing 580a is provided with a housing inlet 581a to allow inflow of oil within the hollow housing 580a. The feeding duct 586 thus starts from the oil chamber 590 and ends at the housing inlet 581a of the hollow housing 580a.

The chamber oil inlet 595 is arranged at a different height (level) with respect to the feeding duct 586. In more detail, the chamber oil inlet 595 is arranged at a level above the feeding duct 586, i.e. the chamber oil inlet 595 is arranged at a higher position with respect to feeding duct 586, to retain oil within the hollow housing 580a. More in detail, the feeding duct 586 is closer to a bottom surface of the oil chamber than the chamber oil inlet 595, while the chamber oil inlet 595 is closer to a top surface of the oil chamber than the feeding duct 586.

It has to be also noted that when the tensioner is in use, i.e. when it is constrained to the internal combustion engine by means of one or more fastener (800) or suitable fastening means, the oil inlet chamber 595 is placed at a higher position with respect to the position of the housing inlet 581a. As a result, when the oil supply line 700 is depressurized (e.g. when the internal combustion engine 110 is not active, for example during shutdown), oil flows by gravity outside the tensioner 500 but an amount of oil is retained within the oil chamber to the arrangement of the chamber oil inlet at a level above the feeding duct.

In other words, oil flows from the oil chamber 590 to the supply line 700 through the chamber oil inlet 595. This occurs until the free surface of oil in the oil chamber 590 drops below the level (height) of the chamber oil inlet 595. At this point the oil is retained within the oil chamber 590. As mentioned, the feeding duct 586 is placed at a lower level (lower position) with respect to the chamber oil inlet 595. Thanks to this, in such a condition the free surface of oil is placed at a higher level (position) with respect to the feeding duct, so that the feeding duct remains filled with oil.

In particular, the free surface of oil is placed at a higher level (position) with respect to the hollow housing inlet 581a, so that, when oil chamber 590 is partially emptied (when the free surface of oil is placed just below the chamber oil inlet 595), oil is still retained within the hollow housing 580a.

According to an embodiment, the tensioner 500 is provided with a detachable wall 590, e.g. a detachable plate-shaped element, that is in turn provided with the chamber oil inlet 595. In particular, the detachable wall 590a can be reversibly constrained to the support body 580. According to an embodiment, as for example shown in the figures, the detachable wall 590a is constrained to the external surface 585 of the support body 580. More in derail, the detachable wall 590 is constrained to a face 585a of the support body 580 that surrounds the oil chamber 590. As a result, a first portion 591a of the detachable wall 590a closes the oil chamber 590, while a second portion 592a, surrounding the first portion 591a, is constrained to the support body 580. In other words, the detachable wall 590a protrude laterally from the oil chamber 590, so that the portion of the detachable wall 590a protruding from the oil chamber 590 (i.e. the above mentioned second portion 592a) is engaged to the support body 580. As a result, according to an embodiment, the dimension of the detachable wall 590a are greater than the dimensions of the section of the oil chamber, so that it is not possible to insert the detachable wall 590a within the oil chamber 590.

According to a first embodiment, the detachable wall 590a is a gasket, and in particular it is a rubber gasket, to prevent leakages of oil from the oil chamber 590. Typically the gasket is shaped as a plate.

According to a different embodiment, the detachable wall 590a may be a metal plate. The sealing of the oil chamber may be assured e.g. thanks to a tight engagement between the tensioner 500 and a relevant engine connection portion 111 of the internal combustion engine 110.

In general, the detachable wall 590a (e.g. a plate-shaped element) is preferably arranged on the support body 580 so that, in use (when the tensioner is constrained to the internal combustion engine), it is interposed between the engine connection portion engine. As a result, the above mentioned undesired rattle noise is avoided also in these conditions.

While at least one exemplary embodiment has been presented in the foregoing summary and detailed description, it should be appreciated that a vast number of variations exist. It should also be appreciated that the exemplary embodiment or exemplary embodiments are only examples, and are not intended to limit the scope, applicability, or configuration in any way. Rather, the foregoing summary and detailed description will provide those skilled in the art with a convenient road map for implementing at least one exemplary embodiment, it being understood that various changes may be made in the function and arrangement of elements described in an exemplary embodiment without departing from the scope as set forth in the appended claims and their legal equivalents.

REFERENCE NUMBERS 100 automotive system 110 internal combustion engine (ICE) 111 engine connection portion 120 engine block 125 cylinder 130 cylinder head 135 camshaft 135a camshaft sprocket 140 piston 145 crankshaft 145a crankshaft sprocket 150 combustion chamber 155 cam phaser 160 fuel injector 170 fuel rail 180 fuel pump 190 fuel source 200 intake manifold 205 air intake duct 210 intake air port 215 valves of the cylinder 220 exhaust gas port 225 exhaust manifold 230 turbocharger 240 compressor 250 turbine 260 cooling system 270 exhaust system 275 exhaust pipe 280 exhaust aftertreatment device 290 VGT actuator 300 EGR system 310 EGR cooler 320 EGR valve 330 throttle body 340 mass airflow and temperature sensor 350 manifold pressure and temperature sensor 360 combustion pressure sensor 380 coolant and oil temperature and level sensors 400 fuel rail pressure sensor 410 cam position sensor 420 crank position sensor 430 exhaust pressure and temperature sensor 445 accelerator pedal position sensor 450 electronic control unit (ECU) 500 tensioner 510 tensioning element 510a plunger 510b guide member 520 elastic element 580 support body 580a hollow housing 581a hollow housing inlet 585 external surface of the support body 585a face of the support body 586 feeding duct 590 oil chamber 590a detachable wall 595 chamber oil inlet 600 endless drive element (chain/belt) 700 supply line 800 fastener

Claims

1. A tensioner (500) for an endless drive element (600) of an internal combustion engine (110), the tensioner comprising a support body (580) and a tensioning element (510), the support body (580) comprising a hollow housing (580a), an oil chamber (590), a feeding duct (586) connecting the hollow housing (580a) to the oil chamber (590), wherein the tensioning element (510) is at least partially inserted within the hollow housing (580a) in a movable manner with respect to said support body (580), an elastic element (520) biases said movable tensioning element for imparting tension to said endless drive element, the oil chamber (590) further comprising a chamber oil inlet (595) to fluidly connect the oil chamber (590) to an oil supply line (700) of the internal combustion engine (110), wherein the chamber oil inlet (595) is arranged at a level above the feeding duct (586) to retain oil within said hollow housing (580a) and said oil chamber (590).

2. The tensioner (500) according to claim 1, wherein the chamber oil inlet (595) is arranged on a wall (590a) detachable from the support body (580).

3. The tensioner (500) according to claim 2, wherein said detachable wall (590a) is a gasket.

4. The tensioner (500) according to claim 3, wherein said gasket is made of a material selected from rubber, plastic, metal, or combinations of the above.

5. The tensioner (500) according to any claim 2 to 4, wherein said wall (590a) is coupled to the external surface of the support body (580).

6. The tensioner (500) according to any of the preceding claims, comprising one or more fastener (800) to constrain said support body (580) to an engine connection portion (111) of an internal combustion engine (110) so that the chamber oil inlet (595) is arranged at a level above the feeding duct (586) to retain oil within said hollow housing (580a) and said oil chamber (590).

7. The tensioner (500) according to any of the preceding claims, wherein the tensioning element (510) comprises a plunger (510a), movable in a reciprocating manner within the hollow housing (580a).

8. The tensioner (500) according to any of the preceding claims, wherein the tensioning element comprises a guide member (510b) to guide the endless drive element (600).

9. An internal combustion engine (110) comprising a tensioner (500) according to any of the preceding claims, wherein an oil chamber (590) of the tensioner (500) is fluidically connected to an oil supply line (700) of the internal combustion engine (110) via the chamber oil inlet (595).

10. The internal combustion engine (110) according to claim 9, wherein the chamber oil inlet (595) is arranged on a gasket (590a) interposed between an engine connection portion (111) and the support body (580) of the tensioner (500).