Improved filtering device for use in oil

Abstract

Filtering device (5) comprising a hub portion (2') connectable to a hub / shaft (2) rotating around an axis (A) and a crown (6) mounted coaxially and rotationally free with respect to the hub portion (2'), said crown (6) being operatively connected to a motor element (3), the crown (6) comprising a first element (7) and a second element (8) connected together to define a space (12) and a filtering unit operatively interposed between the crown (6) and the hub portion (2') housed in the space (12), the first and second elements (7, 8) defining respective holes (51, 52) configured to allow the passage of oil from the external space towards the space (12) through the crown (6).

Description

[0001] " IMPROVED FILTERING DEVICE FOR USE IN OIL"

[0002] Cross-Reference to Related Applications

[0003] This Patent Appl ication claims priority from Italian

[0004] Patent Application No . 102024000018238 filed on August 2 , 2024 , the entire disclosure of which is incorporated herein by reference .

[0005] Technical Sector

[0006] The present invention relates to a filtering device , preferably a filtering device for use in oil .

[0007] The present invention preferably, though not exclusively, applies to a transmission for a heavy- vehicle power take-of f , such as an agricultural vehicle or truck . This application will be referred to below by way o f example .

[0008] State of the Art

[0009] As is well known, the drive shaft in internal combustion engines is subj ect to torsional vibrations due to the periodic stresses caused by combustion in the cylinders .

[0010] These vibrations are particularly intense when starting the engine and at low engine speeds , as well as with special design solutions such as the use of dual-clutch gearboxes or start-stop systems .

[0011] In particular, the drive shaft can be used to supply power to power take-of fs , also known as PTOs , in work vehicles , such as agricultural vehicles , trucks or earth- moving vehicles .

[0012] In this case , torsional vibrations result in rotation irregularities of the transmission elements , such as the gear wheels composing it . Clearly, these vibrations reduce the fatigue li fe of these gear wheels and can result in overloads that cause sudden failures .

[0013] In addition, these vibrations generate annoying noi ses that are also a source of energy inef ficiency .

[0014] Moreover, the aforesaid power take-of fs may be subj ect to temporary or variable loads on the user ' s side . These temporary / variable loads also impose oscillating loads on the transmission, which is thus further overloaded .

[0015] They are known elastic couplings adapted to reduce these vibrations during the passage of the torque along the transmission shafts . However, these systems are inef fective in reducing the transmission of vibrations along the transmission .

[0016] Moreover, given the positioning in the engine , which is lubricated by the relative oil , known grease systems are not particularly ef fective as they tend to contaminate the engine / transmission oil .

[0017] The aim of the present invention is to create a transmission that solves the aforesaid technical problem simply and cost-ef fectively .

[0018] Summary of the Invention The aforesaid aim is achieved by a filtering device and a transmission as claimed in the appended claims forming an integral part of the present description .

[0019] Brief Description of the Drawings

[0020] A preferred embodiment is described below for a better understanding of the present invention, provided by way of non-limiting example with reference to the accompanying drawings , wherein :

[0021] • Figure 1 is a perspective view of a filtering device coupled to a transmission element according to the invention;

[0022] • Figure 2 is an exploded view along the axis A of the filtering device in Figure 1 ;

[0023] • Figure 3 is a first axial section view along the rotation axis of the filtering device in Figure 1 ; and

[0024] • Figure 4 is a second axial section view along the rotation axis of the filtering device in Figure 1 . Detailed description of the Invention

[0025] The attached figures show a portion of a transmi ssion 1 essentially comprising a shaft / hub 2 extending along a rotation axis A and a first gear wheel 3 defining a first toothing and a second gear wheel (not shown) defining a second toothing and carried by the shaft / hub 2 , e . g . by means of a groove 4 .

[0026] Clearly, although not shown, the first and second gear wheels 3 , through their respective toothing, engage further transmission elements 1 .

[0027] Advantageously, the second gear wheel is carried fixed by the shaft 2 , in detail by the aforesaid groove 4 on one end thereof , while the first gear wheel 3 is carried rotationally free with respect to the shaft 2 , e . g . by rolling supports , as shown .

[0028] According to the invention, the toothing of the first gear wheel 3 is operatively connected to the shaft 2 by a filtering device 5 configured to filter the torsional oscillations occurring between the shaft 2 and the gear wheel 3 .

[0029] In detail , the filtering device 5 comprises an annular crown 6 supported rotationally free outside the shaft 2 and configured to rigidly carry a toothing of the transmission portion 1 . In detail , the annular crown 6 is connected to the first gear wheel 3 .

[0030] The filtering device 5 is therefore placed in a lubricated environment , i . e . where lubricating oil is present , for example an engine compartment or transmission compartment , and the first gear wheel 3 represents a motor element adapted to transmit a torque to the crown 6 .

[0031] The first gear wheel 3 could be replaced by a similar element , such as a belt , a rolling contact element or other motion transmitting element . The crown 6 essentially comprises a first element 7 and a second element 8 connected together to define a space 9 .

[0032] Advantageously, the first element 7 comprises an annular wall 11 of axis A and a radial wall 12 , integral with the annular wall 11 and preferably made in a single piece with it , extending radially towards the shaft 2 .

[0033] In detail , the radial wall 12 is configured to be connected to the gear wheel by a corresponding mechanical connection (not visible in the section of Figure 2 ) . For this purpose , holes are provided to house fasteners such as screws or rivets .

[0034] The second element 8 comprises an annular wall 13 of axis A and a radial wall 14 , integral with the annular wall 13 and preferably made in a single piece with it , extending radially towards the shaft 2 .

[0035] In the described embodiment , the second element 8 is fitted in the first element 7 so as to form the aforesaid space 9 which is axially comprised with respect to the axis A by the radial walls 11 and 13 and radially delimited with respect to the axis A on one side by the annular wall 12 of the second element 8 and open towards the shaft 2 .

[0036] At least one of the first and second elements 7 , 8 comprise two diametrically opposite prominences 14 , 15 extending axially inside the chamber 9 .

[0037] In the embodiment described, in particular, both of the first and second elements 7 , 8 comprise prominences 14 , 15 extending from the radial walls 11 , 13 ( see Figure 2 ) .

[0038] These prominences 14 , 15 are advantageously facing each other and thus divide the space 9 into two portions preferably of equal si ze .

[0039] Preferably, the prominences 14 and 15 are carried f ixed by the respective walls or, alternatively, are made in a single piece therewith .

[0040] The filtering device 1 further comprises a filtering unit operatively interposed between crown 6 and shaft 2 .

[0041] In particular, the filtering unit comprises at least one elastic group 20 (better visible in Figures 2 and 3 ) , e . g . two elastic groups 20 that are arcuate and arranged circumferentially free in the respective portions of the space 9 delimited by the prominences 14 , 15 .

[0042] Each of the elastic groups 20 comprises at least one spring, in the case described a helical and arcuate spring 21 mounted between the aforesaid prominences 14 , 15 .

[0043] Obviously, several springs can be provided, in series or parallel with each other, with fixed or variable sti f fnesses , or housed in slides facilitating the sliding of the elastic groups in the space 9 between the prominences 14 , 15 .

[0044] Descriptive examples are reported in Publications IT102015000009369 Al , IT102015000009371 Al or IT102017000021137 Al , the contents of which are incorporated by reference in this Application and applicable where possible with regard to the filtering unit interposed between hub 2 ' and crown 6 .

[0045] The filtering device 1 further comprises an actuator 25 driven by the shaft 2 configured to selectively cooperate in contact with the elastic groups to transmit a torque between hub portion 2 ' and crown 6 .

[0046] The actuator 25 comprises two spokes 26 free to circumferentially move in the space 9 and adapted to cooperate in contact , circumferentially, with the elastic groups 20 as described hereinafter .

[0047] Advantageously, the actuator 25 is carried by a hub portion 2 ' attachable to the shaft 2 . In the embodiment shown, the hub portion 2 ' is made in a single piece with the shaft 2 , thus forming a radial flange extending radially from the shaft 2 on the opposite side of the second gear wheel 4 .

[0048] In detail , the actuator 25 is carried by the hub portion 2 ' by means of a mechanical coupling 27 , e . g . by means of a riveted coupling .

[0049] The actuator 25 can be placed in contact with the elastic groups 20 , in particular with a circumferential interference value so as to preload the elastic groups 20 themselves inside the space 9 . Alternatively, it can be placed with an angular range with respect to the elastic groups 20 , i . e . some angular backlash before contacting them .

[0050] The filtering device 1 may further comprise a damping system 40 configured to provide damping of a predetermined value upon rotation between hub 2 and crown 6 . In the embodiment described, it extends between the first gear wheel 3 and the actuator element 25 .

[0051] In particular, the damping system 40 comprises a sealing element 42 configured to be placed in contact with the gear wheel 3 ( or the actuator 25 , alternatively) and an elastic element 41 configured to impart an axial compressive force along the axis A as in the case shown .

[0052] In particular, the elastic element 41 may comprise a leaf spring, advantageously of the conical or Belleville washer spring type , carried integral with the actuator 25 or a diaphragm spring clamped thereon .

[0053] Thus , the spring defines an internal end and an external end, where the external end cooperates with the sealing element 42 to provide it with the compressive force along the axis A.

[0054] The internal end is rigidly carried by the actuator 25 and, in the case described, is advantageously attached to the hub portion 2 ' .

[0055] The filtering device 1 can also be provided with a dynamic damper (not shown) such as a seismic mass damper or inertia or viscous ring damper . Such a damper could be attached to the hub portion 2 ' on the opposite side of the first gear wheel 3 ' .

[0056] It can be further noted that the first and second elements 7 , 8 are both provided with axial openings 51 , 52 along the rotation axis of the filtering device of Figure 1 that are configured to allow the passage of oil into the space 9 .

[0057] In detail , the openings 51 , 52 are made on the respective radial walls 11 , 13 . Advantageously, they are circular in shape and are equal in number .

[0058] Even more advantageously, the holes 51 on the first element 7 have a larger diameter than the holes 52 on the second element 8 .

[0059] Additionally, the holes 51 and 52 of the first and second elements 7 , 8 are parallel to the axis A but not coaxial with each other .

[0060] Advantageously, the holes 51 on the first element 7 are placed radially outside with respect to the holes 52 on the second element so as to define a predetermined oil level within the space 9 .

[0061] Advantageously, the first gear wheel 4 is also provided with holes 53 configured to allow the passage of oi l . These holes 53 are advantageously coaxial with the holes 51 of the first element 51 and advantageously facing it , i . e . continuous to it , as the radial wall 11 is in contact therewith .

[0062] In particular, the holes 51 of the first element 7 , the holes 52 of the second element 8 and ( i f present ) the holes 53 of the first gear wheel 4 are circumferentially spaced from each other along the longitudinal axis A and, in particular, equally spaced from each other . In the described embodiment , there are between four and six of them .

[0063] Preferably, the filtering device 1 comprises a seal 54 , such as an o-ring, radially interposed between the radial wall 11 and the f irst gear wheel so as to prevent the escape of oil flowing between the aforementioned holes 53 and 51 . Advantageously, one of the device 1 and the first gear wheel 4 comprises a cover 55 configured to define a space 56 adapted to form an oil reservoir, which can be directed towards the space 9 , by the holes 51 in the first element 7 .

[0064] In the embodiment described, the cover 55 is annular and carried by the first gear wheel 4 , and comprises a first , cylindrical , portion 55 ' rigidly carried by the first gear wheel 4 and a second, radial , portion 55 ' ’ extending radially inwards from an end of the first portion 55 ' so as to define a space 56 .

[0065] Advantageously, the first portion 55 ' is housed, under pressure , in a seat defined in the gear wheel 4 . The space 56 is thus radially delimited by the first portion 55 ' , externally, and open, internally, while it is axially delimited, on one side by the gear wheel 4 , in the portion defining the holes 53 , and on the other side delimited by the second portion 55 ' ’ .

[0066] The operation of the transmission and filtering device is described hereinafter .

[0067] In the first "driving mode" operating step constituting the normal operation of the transmission 1 , the first gear wheel 3 drives the crown 5 . Imagining a condition in which the backlash between elastic groups 20 and spokes 26 is recovered, the contact between them drives the hub portion 2 ' , and thus the shaft 2 , and the second gear wheel 4 into rotation . Should the spokes 26 be placed with some backlash, this condition would be recovered first . During this operation, any torsional oscillations are recovered by the elastic means 21 .

[0068] The foregoing occurs , symmetrically, in the "overrunning" condition, i . e . when the speed of the hub portion 2 ' tends to exceed that of the crown 6 .

[0069] Depending on the damping present between the hub portion 2 ' and the crown 6 , as is well known, hysteresis may be present with respect to the two operations described above .

[0070] The actuator 25 , whether with preloaded contact or spaced from the elastic groups , allows or not for angular backlash between hub portion 2 ' and crown 6 . During the movement between hub portion 2 ' and crown 5 , the damping system 40 is driven to rotate around the axis A. During this sliding, it provides a force along the axis A to the cover 11 damping the rotation between hub portion 2 ' and crown 6 .

[0071] I f present , the damper further contributes to dampening torsional oscillations between crown wheel 6 and hub portion 2 ’ .

[0072] In addition, during the movement around the axis A, the centri fugal force tends to suck the oil present in the environment around the filtering device 1 through the holes 51 ( and 53 in the present case ) filling the space 9 up to the predetermined level defined by the second holes 52 . In addition, the cover on the first gear wheel 4 facilitates the presence of a continuous oil reservoir in the space 56 .

[0073] The advantages of a pulley 1 according to the invention are therefore clear .

[0074] Thanks to the presence of the filtering device , it is possible to dampen the torsional oscillations in a transmission portion, particularly between a gear wheel and the relative hub / shaft .

[0075] Advantageously, this device is compact and easily adaptable to various si zes / positioning in the transmission portion . In particular, this is provided thanks to the fact that the actuator can be attached to any portion of the hub, and that the crown 6 can be attached to any portion of the gear wheel, or vice versa.

[0076] In particular, by varying the type / size of the filtering elements and the possible backlash (or preload) between actuator and filtering elements, it is possible to design the type of torsional damping required for the torques involved in a simple way.

[0077] It is finally clear that modifications and variations can be made to the filtering device described without thereby departing from the scope of protection defined by the claims.

[0078] As said, with reference to the elastic groups 20, they could be made without changing their function. For example, they could comprise springs of a different nature or several springs, in series or in parallel. Moreover, the elastic groups could be four and so could the actuator spokes.

[0079] The dynamic damper, as said, could be absent and the actuator could be carried differently by the hub portion 2', which could be attached to the shaft and thus made as a different element.

[0080] Moreover, the shape of the damping system 40 may vary according to the limits stated in the claims.

[0081] Similarly, the motor elements, such as the gear wheel 3, could be replaced by other elements, such as a belt, or still be a different type of gear wheel.

[0082] Furthermore, the number of holes 51, 52, 53, their diameter and position may vary.

[0083] Similarly, the sealing element 54 or cover 55 may be absent or have a different configuration.

Claims

1.CLAIMS1.- Filtering device (5) comprising a hub portion (2' ) connectable to a hub / shaft (2) rotating around an axis (A) and a crown (6) mounted coaxially and rotationally free with respect to said hub portion (2' ) , said crown (6) being operatively connected to a motor element (3) , said crown (6) comprising a first element (7) and a second element (8) connected together to define a space (12) and a filtering unit operatively interposed between said crown (6) and said hub portion (2' ) housed in said space (12) , said first and said second elements (7, 8) defining respective holes (51, 52) configured to allow the passage of oil from the external space towards said space (12) through said crown ( 6 ) .2.- Filtering device according to claim 1, wherein the holes (51) of said first element (8) and the holes (52) of said second element (7) have different diameters.3.- Filtering device according to claim 1 or 2, wherein the holes (52) of said second element have a smaller diameter than the holes (51) of said first element (7) .4.- Filtering device according to one of the preceding claims, wherein the holes (51) of said first element (8) and the holes (52) of said second element (7) have an axis parallel to said axis (A) and are not coaxial with each other .5.- Filtering device according to claim 4, wherein the holes (52) of said second element (8) are radially internal to said holes (51) of said first element (7) around said axis (A) .6.- Filtering device according to one of the preceding claims, wherein said holes (51, 52) of said first and second element (7, 8) are circumferentially spaced around said axis (A) .7.- Filtering device according to one of the preceding claims, wherein the holes (52) of said second element (8) are equal in number to said holes (51) of said first element (7) .8.- Filtering device according to one of the preceding claims, wherein said filtering group comprises at least one elastic group (20) arranged circumferentially with respect to said hub portion (2' ) and to said crown (6) and interposed, each, between a pair of first elements (26) integral with said hub portion (2' ) and between a pair of second elements (14, 15) integral with said crown (6) .9.- Filtering device according to claim 8, wherein said first elements comprise at least two spokes (26) carried by an actuator (25) integral with said hub portion (2' )10.- Filtering device according to one of the preceding claims, one of said first and second elements (7, 8) is operatively connected to said motor element (3) .11.- Filtering device according to claim 10, further comprising a sealing element (54) interposed between said one of said first and second elements (7, 8) and said motor element (3) .12.- Filtering device according to claim 10 or 11, further comprising a cover (55) defining a seat (56) to collect oil to be directed towards said first holes (51) .13.- Transmission portion (1) comprising a first gear wheel (3) , a hub / shaft (2) and a second gear wheel, one of said gear wheels (3) being carried rotatably free with respect to said hub / shaft (2) , said one of said gear wheels (3) being operatively connected to said hub / shaft (2) by means of a filtering device (5) according to one of the preceding claims.14.- Transmission portion according to claim 13, wherein said first gear wheel (3) defines holes (53) coaxial to said holes (51) of said first element (7) .15.- Transmission portion according to claim 14, when claim 13 depends on claim 12, wherein said cover (55) is carried by said first gear wheel (3) .

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