Pulley offset device on a secondary shaft driven under mechanical tension

Abstract

The invention relates to a method and a device (20) for axially offsetting, under tension, a return element (1) of a transmission device (10) transmitting a rotary motion to a shaft (3) about an axis (A). This return element (1) is mounted coaxially to said shaft (3) and driven under continuous mechanical tension by a drive means (2), belt or chain, and subjected to a tension force (F). This device (20) comprises an upper arm (21) adapting, directly or via a gripper (35), to the return element (1) to absorb the tension force (F). This upper arm (21), or an accessory (40, 35) sliding on said upper arm (21), allows axial translation of the return element (1), with an axial clearance stroke greater than a predetermined clearance stroke allowing axial disengagement of the return element (1), which remains subjected to said tension force (F). Abstract figure: [Fig. 6]

Description

Title of the invention: PULLEY OFFSET DEVICE ON A SECONDARY SHAFT DRIVED UNDER MECHANICAL TENSION

[0001] The invention relates to a tensioned axial offset device of a return wheel comprising a transmission device for transmitting a rotary motion between a primary shaft and a secondary shaft rotating about an axis of rotation, said return wheel comprising at least one pulley or at least one wheel and being assembled coaxially to said secondary shaft and driven under continuous mechanical tension by at least one drive means comprising at least one belt or chain, which comprises said transmission device between said primary shaft and said return wheel and which is subjected to a tension force.

[0002] The invention further relates to a method of offsetting such a return unit of a transmission device for the transmission of a rotary motion between a primary shaft and a secondary shaft rotating about an axis of rotation, by use of such a device.

[0003] During mechanical work, it is often necessary to laterally offset a pulley, or a toothed or splined wheel, on the secondary shaft that carries it, and it is advantageous to leave the belt or chain tensioner pre-tensioned during the operation. One application is work on a vehicle engine, particularly in the context of after-sales service.

[0004] Document FR2813545B1 describes a device for removing toothed belt pulleys mounted on automotive idler motors using a puller comprising a removal disc equipped with pull rods and a central spindle control, with guiding, centering and locking features to adapt to different pulley configurations. However, prior removal of the belt remains necessary.

[0005] Work on systems with belt or chain drives generally requires that the belt or chain tensioner be released / disengaged, meaning that it does not apply tension to the belt or chain, in order to perform work on the components driven by that belt or chain. This leads to removing the belt or chain, which is a lengthy and costly process, and necessitates the reverse procedure to put the mechanism back into service.

[0006] The invention aims to eliminate these operations. Indeed, to remove the belt or chain, it is necessary to release the tensioner to relieve the tension applied to the belt or chain before working on the system, which is time-consuming and... resources. For example, in the context of a timing belt of an automotive internal combustion engine, commonly called a timing belt, access to the tensioner can prove to be very complex, therefore costly in time and energy.

[0007] The objective of the present invention is to remedy these drawbacks by providing a tool for offsetting, in particular axially, a pulley or toothed or toothed wheel of a belt or chain driven system, allowing mechanical interventions on the driven system without dislodging the belt or chain.

[0008] To achieve this objective, the invention proposes a pulley or wheel offset device on a secondary shaft driven under mechanical tension.

[0009] For this purpose, the invention relates to an axial offset device under tension of a return wheel comprising a transmission device for the transmission of a rotary motion between a primary shaft and a secondary shaft rotating about an axis of rotation, said return wheel comprising at least one pulley or at least one wheel and being assembled coaxially to said secondary shaft and driven under continuous mechanical tension by at least one drive means comprising at least one belt or chain, which comprises said transmission device between said primary shaft and said return wheel and which is subjected to a tension force.

[0010] According to the invention, said device comprises at least one upper arm extending along the direction of said axis of rotation and arranged to adapt, directly or through at least one gripper, to said return wheel to take up said tension force of said at least one drive means, the geometry of said at least one upper arm or of said gripper is adapted to cooperate with a support surface comprising said return wheel, and said at least one upper arm, or an offset translation module mounted to slide on said upper arm, or said gripper mounted to slide on said upper arm, is arranged to allow axial translation of said return wheel along the axial direction of said axis of rotation,with an axial clearance stroke greater than a predetermined clearance stroke allowing the separation between said return wheel and said secondary shaft and allowing the axial clearance of said return wheel, which remains subjected to said tensile force from said at least one drive means.

[0011] Thanks to the invention, it is possible to axially offset such a moving part, pulley or gear, always subjected to the tension force applied to the drive means, belt or chain.

[0012] Advantageously, said upper arm carries said offset translation module mounted sliding on said upper arm, said offset translation module carrying at least one said gripper, either directly or through an adjustment device with a stroke adjustable in a direction orthogonal to that of said axis of rotation.

[0013] It is thus possible to adjust the position in space of the referring mobile very precisely.

[0014] Advantageously, said device includes at least one support arranged to be fixed to an element enabling the resumption of said tensile force of said at least one drive means, or to a main solid module comprising said transmission device and to which said at least one support can be fixed for the resumption of said tensile force of said at least one drive means.

[0015] This attachment to an element more massive than the device itself and the return mobile ensures the perfect resumption of tension forces.

[0016] Advantageously, said transmission device comprises a solid main module on which is assembled a removable upper group according to a unique disassembly direction imposed by at least one positioning element.

[0017] In this case, the most massive part of the transmission device is advantageously usable for fixing the shifting device.

[0018] Advantageously, said removable upper group comprises at least one lower module carrying said secondary shaft and guiding it in rotation around said axis of rotation, said secondary shaft being held in position by at least one upper module removably fixed on said at least one lower module.

[0019] The secondary shaft is thus maintained by the cooperation of removable elements.

[0020] Advantageously, said transmission device is a thermal engine transmission device, said main solid module is a cylinder head, and said secondary shaft is a camshaft, said lower module is a camshaft carrier, and said upper module is a cylinder head cover.

[0021] This application to a thermal engine is particularly advantageous, because it avoids the removal of the transmission element, and allows the geometric timing marks to be retained in relation to the crankshaft.

[0022] Advantageously, said return mobile comprises a counterbore arranged to cooperate in a complementary manner and in abutment support with a front end which comprises said secondary shaft.

[0023] The depth of this counterbore advantageously corresponds to the predetermined clearance stroke. The complete extension of the shaft from this counterbore ensures the possibility of movement of the return gear.

[0024] Advantageously, said return mobile is fixed by at least one screw to a threaded hole in said secondary shaft.

[0025] Screw fixing is the simplest for easy assembly and disassembly.

[0026] Advantageously, said return mobile is fixed by a single screw to a single thread in said secondary shaft, at the level of said axis of rotation.

[0027] The number of components is thus reduced.

[0028] The invention further relates to a method of offsetting a return unit of a transmission device for the transmission of a rotary motion between a primary shaft and a secondary shaft rotating about an axis of rotation, by use of such a device.

[0029] According to the invention, in this method there follows a first step of fixing the device to an element enabling the generation of the resumption of said tension force of said at least one drive means, and of resumption of the force at the level of said return mobile by said at least one upper arm of said device, a second step of axial translation of said return mobile along the direction of said axis of rotation, and after a translation greater than or equal to the value of said predetermined clearance stroke, a third step of at least partial dismantling of said transmission device under the action of a dismantling force.

[0030] These operations are simple, ensure the safety and correct positioning of the elements present, and allow the return mobile to remain subjected to the tension force of the drive means.

[0031] The invention will be further detailed by describing non-limiting embodiments, and based on the accompanying figures illustrating variants of the invention, in which: - [Fig. 1] schematically illustrates in front view with respect to its axis of rotation, a moving part of a transmission device, here a pulley subjected to a tension force of a transmission means, here a belt; this pulley has an axial attachment by a screw to a secondary shaft not visible in the figure; - [Fig.2] schematically illustrates, partially and in cross-section, passing via the axis of rotation of the pulley fixed to the secondary shaft, a transmission device for transmitting a motion imparted by a primary axis not shown in the lower part of the figure, to the secondary axis through the transmission means and the pulley; the transmission device comprises a solid main module, in the lower right part of the figure, on which is assembled an upper group removable according to a single direction of disassembly imposed by positioning pins; this removable upper group comprises a lower module carrying the secondary shaft and guiding it in rotation around the axis of rotation, the secondary shaft being held in position by two upper modules removably fixed to this lower module; - [Fig.3] schematically illustrates, similarly to [Fig.2], a device axial offset under tension of the return unit, according to the invention, assembled with the transmission device: this shifting device comprises a lower support which is fixed to the main solid module, and an upper arm carrying the pulley, and taking up the tension force applied by the timing belt; the position of the assembly corresponds to the end of a first stage of a shifting process according to the invention; - [Fig.4] schematically illustrates, similarly to [Fig.3], the same together at the end of a second stage of the shifting process, according to which the pulley, still subjected to the tension of the timing belt, is translated to the left of the figure, in order to allow access to the secondary shaft for its dismantling or other purposes; - [Fig.5] schematically illustrates, similarly to [Fig.4], the same assembly at the end of a third stage of the offset process, according to which the pulley, still subjected to the tension of the timing belt, is held under tension in the position of [Fig.4], and according to which the elements of the upper group have been removed from the main solid module by translation along the direction of the positioning pins; - [Fig.6] schematically illustrates, similarly to [Fig.4], the use of another variant of the offset device, in which this tooling includes, mounted sliding on the upper arm, an offset translation module, which carries, through an adjustment device having a stroke adjustable in a direction orthogonal to that of the axis of rotation of the secondary shaft (here in the direction of the gravity field), a gripper which itself carries the pulley always subjected to the tension force of the belt; - [Fig.7] is a flowchart illustrating the successive steps of the process of offset according to the invention.

[0032] The invention relates to a pulley or wheel offset device on a secondary shaft driven under mechanical tension.

[0033] The invention consists of using a shifting tool, in particular axial, of a pulley or a toothed wheel, when the belt or chain with which it cooperates remains under tension.

[0034] The tool has a specific geometry allowing it to adapt to the geometry of the pulley or gear, and has a characteristic allowing it to offset this pulley or gear axially, laterally on its secondary shaft.

[0035] This offset, in particular axial, of pulley or toothed wheel makes it possible to carry out mechanical interventions on at least one component driven by this pulley or toothed wheel, and this without removing or misaligning the belt or chain drive tensioning device.

[0036] This operation of shifting a pulley or toothed wheel along its secondary shaft must be able to be carried out with a belt or chain tensioner that remains pre-tensioned.

[0037] The difficulty lies in carrying out the movement, in particular in translation, of the pulley, while keeping the associated belt in place.

[0038] The invention is described herein in a non-limiting manner for an automotive engine return application, and is applicable to other analogous systems.

[0039] The invention relates to a tool, which is a device 20 for axially offsetting under tension of a return mobile 1 which includes a transmission device 10 for the transmission of a rotary motion between a primary shaft and a secondary shaft 3 mobile in rotation around an axis of rotation A.

[0040] This return unit 1 comprises at least one pulley or at least one wheel, and is assembled coaxially to the secondary shaft 3, and the return unit 1 is driven under continuous mechanical tension by at least one drive means 2 comprising at least one belt or chain, which comprises the transmission device 10 between the primary shaft and the return unit 1 and which is subjected to a tension force F.

[0041] According to the invention, the device 20 comprises at least one upper arm 21 extending along the direction of the axis of rotation A, and which is arranged to adapt, directly or through at least one gripper 35, to the return mobile 1 to take up the tension force F of this at least one drive means 2.

[0042] The geometry of this at least one upper arm 21, or of the gripper 35, is adapted to cooperate with a support surface 9 that comprises the return mobile 1.

[0043] This at least one upper arm 21, or an offset translation module 40 mounted to slide on the upper arm 21, or a gripper 35 mounted to slide on the upper arm 21, is arranged to permit axial translation of the return wheel 1 along the axial direction of the axis of rotation A, with an axial clearance stroke which is greater than a predetermined clearance stroke DEG permitting the separation between the return wheel 1 and the secondary shaft 3 and permitting the axial clearance of the return wheel 1, which remains subject to the tensile force F of this at least one drive means 2.

[0044] More particularly, the upper arm 21 carries such an offset translation module 40 mounted to slide on the upper arm 21, the offset translation module 40 carrying at least one such gripper 35, either directly or through an adjustment device 30 with a stroke adjustable in a direction orthogonal to that of the axis of rotation A.

[0045] More particularly, the device 20 comprises at least one support 22 which is arranged to be fixed to an element enabling the transfer of the tension force F of the drive means 2, or to be fixed to a solid main module 7 that includes the transmission device 10 and to which this support 22 can be fixed for the resumption of the tension force F of the drive means 2.

[0046] Advantageously, the upper arm 21 is positioned above the support 22 relative to the gravitational field; the upper arm supports both the tension applied to the pulley and its weight. More specifically, as shown in [Fig. 3], the upper arm 21 and the support 22 extend parallel to each other in a horizontal direction perpendicular to the gravitational field.

[0047] More particularly, the transmission device 10 comprises a solid main module 7 on which is assembled a removable upper group according to a unique disassembly direction D imposed by at least one positioning element 8.

[0048] More particularly, the removable upper group comprises at least one lower module 5 carrying the secondary shaft 3 and guiding it in rotation around the axis of rotation A, the secondary shaft 3 being held in position by at least one upper module 6 removably fixed on this at least one lower module 5.

[0049] More specifically, the transmission device 10 is a thermal engine transmission device, the main solid module 7 is a cylinder head, and the secondary shaft 3 is a camshaft, the lower module 5 is a camshaft carrier, and the upper module 6 is a cylinder head cover.

[0050] More particularly, the return mobile 1 includes a counterbore 13 which is arranged to cooperate in a complementary manner and in abutment support with a front end 31 which includes the secondary shaft 3.

[0051] More particularly, the return mobile 1 is fixed by at least one screw 4 to a threaded hole 34 which is part of the secondary shaft 3. More particularly still, the return mobile 1 is fixed by a single screw 4 to a single threaded hole 34 which is part of the secondary shaft 3, at the level of the axis of rotation A.

[0052] The invention further relates to a method of offsetting a return mobile 1 of such a transmission device 10 for the transmission of a rotary motion between a primary shaft and a secondary shaft 3 mobile in rotation around an axis of rotation A, by use of such a device 10.

[0053] According to the invention, in this method, a first step 100 of fixing the device 20 to an element enabling the resumption of the tension force F of at least one drive means 2, and of resumption of the force at the level of the return mobile 1 by the at least one upper arm 21 of the device 20, a second step 200 of axial translation T of the return mobile 1 along the direction of the axis of rotation A, and after a translation greater than or equal to the value of the predetermined clearance stroke DEG, a third step 300 of at least partial dismantling of the transmission device 10 under the action of a dismantling force FD.

[0054] The invention is illustrated in the figures for the case where the return unit is a pulley cooperating with a smooth or toothed belt. Those skilled in the art will be able to transpose the application to the usual case of a toothed wheel cooperating with a chain or a toothed belt.

[0055] [Fig-1] and [Fig.2] illustrate the same mechanism of a transmission device 10. Rotary motion is provided by a belt and pulley system, shown partially. A drive unit 1, consisting of a pulley or a toothed or toothed wheel, rotating about an axis of rotation A, cooperates with a drive means 2, such as a belt, chain, or similar. The pulley 1 is, in particular, but not exclusively, fixed by at least one screw 4 to a threaded hole 34 in a secondary transmission shaft 3 rotating about the axis of rotation A. The elements can be synchronous transmission (with teeth), or non-synchronous smooth transmission, with the possibility of relative slippage between pulley 1 and belt 2.

[0056] The tensioning of the belt 2 results in the application of a radial force F on the return vehicle 1, here the pulley, and on the secondary transmission shaft 3 which carries the pulley.

[0057] In a particular and non-limiting manner, the secondary transmission shaft 3 is guided in rotation by a lower module 5, for example a cradle, and is held in position by at least one upper module 6, for example a cap. The lower module 5 and each upper module 6 together form an upper group, which is itself fixed to a main module 7, and in particular assembled with it by at least one positioning element 8 such as a centering pin or similar, a key, or other, which imposes assembly and disassembly along a single direction D, more particularly orthogonal to the direction of the axis of rotation A.

[0058] The return unit 1, here the pulley, advantageously comprises a coaxial counterbore 13, which is arranged to cooperate in a frontal stop bearing with an end 31 of the secondary transmission shaft 3, as seen in [Fig. 2]. The depth DEG of this counterbore 13 along the axial direction A corresponds to the axial stroke required for removing the upper unit, when the directions D of the centering pins 8 are orthogonal to the direction of the axis of rotation A, which is the most general case.

[0059] In the non-limiting context of a referring automotive application, the main module 7 can for example be likened to the cylinder block, the lower module 5 to the cylinder head or sub-elements of the cylinder head, and the upper module 6 to bearing caps, or a cylinder head cover, retaining the secondary transmission shaft 3, in particular a secondary camshaft or similar.

[0060] [Fig. 3] illustrates the implementation of a device 20 according to the invention, which allows the suspension and displacement of the return unit 1, here the pulley, this The suspension and this offset are performed while keeping the belt tensioner (not shown in the figures) of the transmission device 10 active, thus avoiding the need to access and deactivate this belt tensioner. To achieve this, the device 20 has a geometry that adapts to the shape of the idler wheel 1, here the pulley, in order to absorb the forces F exerted by the belt 2. Once the device 20 is in place and the belt forces F are safely absorbed, the device 20 allows for an axial translation T of the pulley 1 along the axis of rotation A, in extraction relative to the secondary transmission shaft 3, thus obtaining the clearance DEG necessary for removing the upper assembly comprising the lower module 5 and each upper module 6.

[0061] The maneuver is simple, and involves a succession of steps according to the flowchart visible in [Fig.7].

[0062] A first step 100 visible in [Fig.3] concerns the fixing of the device 20 to any element enabling the resumption of any force composing the force F, for example but not necessarily to the main module 7 as illustrated by the figures by means of a support 22 of the device 20.

[0063] The geometry of the device 20 adapts to that of the return unit 1, here the pulley, whether through openings 9 in the pulley, through the through hole 14 in the screw 4, or through any other internal or external geometric surface of the pulley, for example a groove. The position or force of the device 20 can advantageously be adjusted with a dedicated adjustment device 30 as shown in [Fig. 6].

[0064] Depending on the circumstances, the masses involved, and the magnitude of the applied forces, the device 20 can be used either by simply supporting the return vehicle 1, here the pulley, held by gravity to an upper arm 21 of the device 20 during its extraction and displacement maneuver, or with mechanical attachment to this return vehicle 1, for example by screws or other mechanical fixing elements.

[0065] A second step 200 visible in [Fig.4] uses the device 20 to perform an axial translation T of the return unit 1, here the pulley, along the direction of the axis of rotation A, while maintaining the necessary supports to compensate for the belt forces F. This translation T can be performed by sliding the pulley on the device 20, or the device 20 itself can have an offset translation module 40, as seen in [Fig.6], in the manner of a crane trolley, if the geometry of the pulley or its environment limits the size or the travel stroke.

[0066] A third step 300 visible in [Fig. 5] allows, after a translation greater than or equal to the value of the clearance DEG, under the action of a dismantling force FD, the removal of the upper group comprising the lower module 5 and Each upper module 6 is moved in a direction determined by the centering pins 8, specifically a vertical movement along the direction of the gravity field. It is also possible to remove the secondary transmission shaft 3, or any component or subsystem directly or indirectly connected to the freed pulley 1.

[0067] [Fig. 6] shows a secure configuration, in which the device 20 comprises both an offset translation module 40 sliding on the upper arm 21 of the device 20, parallel to the axis of rotation A, allowing longitudinal adjustment of the position of the pulley 1, and from which is suspended by gravity an adjustment device 30, in particular micrometric, of the vertical position of the pulley 1. Naturally the upper arm 21, the offset translation module 40, and the adjustment device 30, are dimensioned to withstand the forces resulting from the tension of the belt 2; the adjustment device 30 can, furthermore, allow a slight modulation of the force F applied to the pulley 1.

[0068] Reassembly is as easy as disassembly, by carrying out the reverse operations, always secured by the presence of tool 20.

[0069] In summary, the invention avoids the unnecessary expenditure of time and energy associated with disabling a belt or chain tensioner, so that the tensioner no longer exerts pressure on the belt or chain, during work on a complex mechanical assembly, particularly, but not limited to, after-sales service on a return automotive internal combustion engine. The invention allows for a significant reduction in time spent and costs.

Claims

1.

2. Demands A tensioned axial offset device (20) of a return wheel (1) comprising a transmission device (10) for transmitting rotary motion between a primary shaft and a secondary shaft (3) rotating about an axis of rotation (A), said return wheel (1) comprising at least one pulley or at least one wheel and being coaxially assembled to said secondary shaft (3) and driven under continuous mechanical tension by at least one drive means (2) comprising at least one belt or chain, comprising said transmission device (10) between said primary shaft and said return wheel (1) and which is subjected to a tension force (F), characterized in that said device (20) comprises at least one upper arm (21) extending along the direction of said axis of rotation (A) and arranged to fit, directly or through at least one gripper (35),said return mobile (1) to take up said tension force (F) of said at least one drive means (2), in that the geometry of said at least one upper arm (21) or of said gripper (35) is adapted to cooperate with a support surface (9) comprising said return mobile (1), and in that said at least one upper arm (21), or an offset translation module (40) mounted to slide on said upper arm (21), or said gripper (35) mounted to slide on said upper arm (21), is arranged to permit axial translation of said return mobile (1) along the axial direction of said axis of rotation (A), with an axial clearance stroke greater than a predetermined clearance stroke (DEG) permitting the separation between said return mobile (1) and said secondary shaft (3) and permitting the axial clearance of said return mobile (1) which remains subjected to said tension force (F) of said at least one drive means (2). Device (1) according to claim 1 characterized in that said upper arm (21) carries said offset translation module (40) mounted to slide on said upper arm (21), said offset translation module (40) carrying at least one said gripper (35), either directly or through an adjustment device (30) with a stroke adjustable in a direction orthogonal to that of said axis of rotation (A).

3. Device (1) according to claim 1 or 2 characterized in that said device (20) comprises at least one support (22) arranged to be fixed to an element enabling the resumption of said tensile force (F) of said at least one drive means (2), or to a solid main module (7) comprising said transmission device (10) and to which said at least one support (22) can be fixed for the resumption of said tensile force (F) of said at least one drive means (2).

4. Device (1) according to any one of claims 1 to 3 characterized in that said transmission device (10) comprises a solid main module (7) on which is assembled a removable upper group in a single disassembly direction (D) imposed by at least one positioning element (8).

5. Device (1) according to claim 4 characterized in that said removable upper group comprises at least one lower module (5) carrying said secondary shaft (3) and guiding it in rotation about said axis of rotation (A), said secondary shaft (3) being held in position by at least one upper module (6) removably fixed on said at least one lower module (5).

6. Device (1) according to claim 5 characterized in that said transmission device (10) is a thermal engine transmission device, in that said main solid module (7) is a cylinder head, and in that said secondary shaft (3) is a camshaft, said lower module (5) is a camshaft carrier, and said upper module (6) is a cylinder head cover.

7. Device (1) according to any one of claims 1 to 6 characterized in that said return mobile (1) comprises a counterbore (13) arranged to cooperate in a complementary manner and in abutment support with a front end (31) comprising said secondary shaft (3).

8. Device (1) according to any one of claims 1 to 7 characterized in that said return mobile (1) is fixed by at least one screw (4) to a thread (34) included in said secondary shaft (3).

9. Device (1) according to claim 8 characterized in that said return mobile (1) is fixed by a single screw (4) to a single tapped hole (34) which comprises said secondary shaft (3), at the level of said axis of rotation (A).

10. A method for offsetting a return bearing (1) of a transmission device (10) for transmitting rotary motion between a primary shaft and a secondary shaft (3) rotating about an axis of rotation (A), by using a device (10) according to any one of claims 1 to 9, according to which the method consists of a first step (100) of fixing the device (20) to an element enabling the resumption of said tension force (F) of said at least one drive means (2), and of resuming the force at the level of said return bearing (1) by said at least one upper arm (21) of said device (20), a second step (200) of axial translation (T) of said return bearing (1) along the direction of said axis of rotation (A), and after a translation greater than or equal to the value of said predetermined clearance stroke (DEG),a third step (300) of at least partial dismantling of said transmission device (10) under the action of a dismantling force (FD).

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