Filter belt wheel

Abstract

A filter pulley (1) comprising a hub (2) adapted to be fixed to a shaft rotating about an axis (A), a crown (3) mounted coaxially and freely rotatably on the hub (2), at least one elastic group (30) arranged circumferentially with respect to the hub (2) and the crown (3), and each elastic group is interposed between a pair of first parts (36) fixedly carried by the hub (2) and a pair of second parts (16) fixedly carried by the crown (3), the filter pulley (1) comprising a dynamic damper (19) carried by the hub (2), the dynamic damper (19) being carried at a distance of less than 130 mm from the opposite end of the hub (2).

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS

[0002] This utility model application claims the priority of Italian patent application No. 102023000007092 filed on April 13, 2023, the entire disclosure of which is incorporated herein by reference. Technical Field

[0003] The invention relates to a filter pulley, preferably a pulley for a crankshaft in an accessory drive of an internal combustion engine. Background Art

[0004] It is well known that the drive shaft in an internal combustion engine is subject to torsional vibrations due to the periodic stresses caused by the combustion in the cylinders. Such vibrations are particularly strong at start-up and at low speeds, as well as in the case of specially constructed solutions (such as, for example, the use of a dual clutch gearbox or a start-stop system).

[0005] Torsional vibrations cause rotational irregularities of the drive pulley of the accessory drive, which are transmitted to accessories via the drive belt, which is therefore subject to periodic tension variations.

[0006] For the purpose of "filtering" the torsional oscillations transmitted from the crankshaft to the belt, a filter pulley is usually used as the drive pulley, the filter pulley being provided with a hub integral with the drive shaft, a crown cooperating with the belt, and one or more elastic elements, through which the torque is transmitted from the hub to the crown. The filter pulley may also be provided with a damper device. An example of such a filter pulley is illustrated in WO2022 / 243857A1.

[0007] However, in case the filter pulley is provided with a damper arrangement, different problems arise.

[0008] In practice, a precise coupling between the damper and the pulley on the crankshaft is required.In practice, the damper device is usually provided with an unbalanced mass designed to compensate for the inertia of the crankshaft.

[0009] However, in known decouplers, securing the damper device to the pulley is complex and time consuming.

[0010] Furthermore, the wheel hub needs to support heavy loads. In particular, in the portion of the wheel hub where the bearings or bushings are located, the loads may be so high that high performance materials such as high performance steels may be used, thereby increasing manufacturing costs.

[0011] Furthermore, due to the presence of both the filter pulley and the damper, a large damping mass is required in order to provide effective damping for the system. A large damping mass is required in order to provide effective damping. Obviously, such a mass value increases the weight of the separator assembly, thereby reducing the maneuverability of the separator assembly and increasing its manufacturing cost.

[0012] Furthermore, the sealing means provided with known separators are usually housed in seats which need to be machined on the hub, thereby increasing the manufacturing costs of the separator.

[0013] In view of the above, there is a need to provide a filter pulley which addresses the above-mentioned shortcomings associated with existing separators and which is achieved in a cost-effective and optimized manner. Utility Model Content

[0014] The above-mentioned purpose is achieved by a filter pulley 1, which includes a hub 2, a crown 3, and at least one elastic group 30. The hub 2 is suitable for being fixed to a shaft rotating around an axis A, and the crown 3 is coaxially and freely rotatably mounted on the hub 2. At least one elastic group 30 is arranged circumferentially relative to the hub 2 and the crown 3, and each elastic group is inserted between a pair of first components 36 fixedly carried by the hub 2 and a pair of second components 16 fixedly carried by the crown 3. The pulley 1 includes a dynamic damper 19 carried by the hub 2, wherein the dynamic damper 19 is carried at a position greater than 80 mm at the relative end distance relative to the hub 2.

[0015] In detail, the mass of the dynamic damper 19 is less than 11 kg.

[0016] Furthermore, the hub 2 comprises a first element 51 and a second element 52 connected together by a fixing device.

[0017] Preferably, the second element 52 is configured to be connected to the shaft, and the first component 36 is carried between the first element 51 and the second element 52 , or is fixedly carried by one of the first element 51 and the second element 52 .

[0018] In detail, the first element 51 and the second element 52 are connected by a first positive coupling 61, which preferably comprises a first protrusion 61' carried in a fixed manner to one of the first element 51 and the second element 52 and a first seat 61" realized in the other of the first element 51 and the second element 52.

[0019] In particular, the dynamic damper 19 comprises a hub portion 21 carried by the first element 51 via a second positive coupling 62, which second positive coupling 62 preferably comprises a second protrusion 62' carried in a fixed manner to one between the first element 51 and the hub portion 21 and a second seat 62" realized in the other between the first element 51 and the hub portion 21.

[0020] In detail, the pair of second parts 16 are protrusions integral with the element 11 of the crown 3 .

[0021] Furthermore, the at least one elastic group 30 slides circumferentially inside the space 10 formed between the first part 36 and / or the second part 16 . BRIEF DESCRIPTION OF THE DRAWINGS

[0022] For a better understanding of the present innovation, preferred embodiments are described below by way of non-limiting examples and with reference to the accompanying drawings, in which:

[0023] · Figure 1 is a perspective view of a pulley according to the present innovation;

[0024] · Figure 2 yes Figure 1 A three-dimensional exploded view of a pulley;

[0025] · Figure 3 yes Figure 1 a cross-sectional radial view of the pulley; and

[0026] · Figure 4 yes Figure 3 Exploded view of a cross-sectional radial view. DETAILED DESCRIPTION

[0027] In the drawings, a filter pulley assembly 1 is shown, comprising: a hub 2 with an axis A, which is suitable for connection to a shaft (not shown), such as a crankshaft of an internal combustion engine; and an annular crown 3, which is externally coaxial with the hub 2 and is supported on the hub 2 in a rotationally free manner by a support device 4.

[0028] The crown 3 comprises an annular portion 5 provided with a profile 6 suitable for cooperating with a poly-V belt (not shown). The crown 3 further comprises a radial wall 7 integral with the annular portion 5 and preferably integral with the annular portion 5, extending radially from the annular portion 5 towards the hub 2, and an inner wall 8 extending from a terminal portion of the radial wall 7 opposite the annular portion 5, and a substantially cylindrical inner wall 8 having an axis A.

[0029] Preferably, the inner wall 8 cooperates with the supporting means 4, which in the disclosed embodiment is represented as a bearing.

[0030] The crown 3 carries a closing element 11 integral with the crown 3 and configured to cooperate with the crown 3 to delimit the space 10. In particular, the closing element 11 comprises an outer cylindrical wall 12 having an axis A, a radial annular wall 13 extending radially from an axial terminal portion of the cylindrical wall 12 opposite the wall 7, and a terminal wall 14 extending axially along the axis A from a terminal portion of the radial annular wall 13 opposite the cylindrical wall 12.

[0031] The closing element 11 is driven into the crown 3 so as to form the above-mentioned space 10 , which is notably an annular space radially comprised between the wall 12 and the wall 8 and axially delimited by the wall 7 and the wall 13 .

[0032] In particular, the radial extension of the wall 13 is smaller than the wall 13 , thus providing an annular gap 15 between the wall 8 and the hub 2 .

[0033] At least one between the crown 3 and the closing element 11 comprises two diametrically opposed projections 16 extending axially inside the space 10 starting from the faced walls 7 and 13. The projections 16 divide the space 10 into two parts, preferably of equal size.

[0034] The above-mentioned projection 16 is fixedly carried by the corresponding wall or alternatively is made in one piece therewith. In the disclosed embodiment, the projection 16 is realized as a protrusion realized integrally in the two walls 7 and 13 .

[0035] The pulley assembly 1 may be further provided with a damper 19, such as a torsional vibration damper, the damper 19 comprising a hub portion 21 fixedly supported by the hub 2, a seismic ring 22 supported by the hub portion 21, and a deformable ring 23 operably inserted between the hub portion 21 and the seismic ring 22; in particular, the deformable ring 23 is made of an elastomeric material.

[0036] In particular, the hub portion 21 includes a coupling portion 21 ′ configured to be fixedly carried by the hub 2 and a disc portion 21 ″ extending from the coupling portion 21 ″ opposite the hub 2 .

[0037] As illustrated, the pulley 1 further comprises at least one elastic group 30 , for example two elastic groups 30 , which are arched and freely arranged circumferentially in respective portions of the chamber 10 defined by the projection 16 .

[0038] Each of the elastic groups 30 comprises at least one spring, in the embodiment described, a helical arch spring 31 mounted between the above-mentioned projections 16 .

[0039] The pulley 1 further comprises an actuator 35 fixedly carried by the hub 2. The actuator 35 has two spokes 36 free to move circumferentially in the space 10 and adapted to interact with the elastic group 30 by contact as described below.

[0040] The actuator 35 can be placed in contact with the elastic groups 30, possibly with a circumferential interference value so as to preload the elastic groups 30 inside the space 10, or alternatively, the actuator 35 can be placed with an angular clearance relative to the elastic groups 30, i.e. an angular gap before contact with these elastic groups 30.

[0041] The pulley 1 may further include a sealing device 40 , in particular a dustproof device 40 , which is configured to isolate the space 10 from the outside.

[0042] In particular, the dust protection device 40 is configured as a dust protection lip, such as a labyrinth seal, which is radially placed in the annular gap 15, in particular between the closing element 11, ie the inner wall 14, and the hub 2. The dust protection device 40 thus isolates the space 10 from the environment.

[0043] In particular, the dust protection device 40 is fixedly carried by the closing element 11 and slides over the outer surface of the hub 2 .

[0044] The dust protection device 40 is preferably realized as a single piece of polymer material.

[0045] Preferably, the pulley 1 further comprises sealing means 45 placed axially between the hub 2 and the crown 3, in particular between the inner wall 8 of the crown 8 and the hub 2. The sealing means 45 thus isolates the space 10 from the supporting means 4.

[0046] Advantageously, the second protection means 45 comprises an elastic element 46 configured to provide an axial compression force along the axis A and a sealing element 47 configured to be placed in contact with the wall 8 .

[0047] Advantageously, the hub 2 comprises a plurality of elements 51 , 52 connected together via corresponding form couplings.

[0048] In particular, the first element 51 carries the actuator 35 and the second element 52 is configured to be fixed to a crankshaft of the engine.

[0049] The second element 52 comprises a substantially cylindrical main element 52' and a coupling element 52' extending axially from the main element 52' and configured to allow coupling with the crankshaft. In the disclosed embodiment, the coupling element 52' is substantially annular, however, it is clear that any shape may be provided depending on the shape required for coupling with the crankshaft.

[0050] It should be noted that the main element 52 ′ delimits the annular gap 15 radially on the inside and therefore supports the first protection device 40 ′.

[0051] The first element 51 comprises a substantially cylindrical main portion 51 ′. Such main portion 51 ″ also carries the above-mentioned spokes 36 of the actuator 35 .

[0052] In more detail, the spokes 36 are carried by frictional contact between the main portions 51 ′, 52 ′ of the first element 51 and the second element 52 .

[0053] In particular, the first element 51 is realized in a different material with respect to the second element 52. In particular, both elements 51, 52 are realized from a metallic material, such as steel, having different mechanical properties.

[0054] Preferably, the metal composition of the elements 51, 52 may be substantially the same, and the surfaces of the first element 51 and the second element 52 may be subjected to different thermal and / or chemical and / or electrochemical surface treatments in order to provide at least the surfaces of the elements 51, 52 with the above-mentioned different mechanical properties.

[0055] In more detail, the first element 51 has a greater hardness relative to the second element 52. In more detail, the hardness of the first element 51 is greater than 20 HRC, ie Rockwell hardness scale, and more preferably is comprised between 20 HRC and 30 HRC.

[0056] As described, the first element 51 and the second element 52 are mechanically coupled by a first shape coupling 61. Preferably, such a first shape coupling 61 comprises a first protrusion 61' carried in a fixed manner to one of the first element 51 and the second element 52 and a first seat 61" realized in the other of the first element 51 and the second element 52; such a first protrusion 61' is configured to be accommodated in the first seat 61". In particular, the first protrusion 61' is seated in the first seat 61" with a preset interference.

[0057] Advantageously, the first protrusion 61 ′ is realized as a cylindrical plug configured to be housed in a cylindrical first seat 61 ″. In the disclosed embodiment, the first protrusion 61 ′ is realized on the first element 51 and the first seat 61 ″ is realized in the second element 52 .

[0058] The first protrusion 61 ′ and the first seat 61 ″ are advantageously parallel to the axis A and more preferably coaxial therewith.

[0059] Advantageously, the first element 51 is connected to the hub part 21 of the damper 19 via a second form coupling 62. Preferably, such a second form coupling 62 comprises a second protrusion 62' carried in a fixed manner to one between the first element 51 and the hub part 21 and a second seat 62" realized in the other between the first element 51 and the hub part 21; such a second protrusion 62' is configured to be housed in the second seat 62". In particular, the second protrusion 62' is seated in the second seat 62" with a preset interference.

[0060] Advantageously, the second protrusion 62 ′ is realized as a cylindrical plug configured to be housed in a cylindrical second seat 62 ″. In the disclosed embodiment, the second protrusion 62 ′ is realized on the first element 51 and the second seat 62 ″ is realized in the hub part 21 .

[0061] The second protrusion 62' and the second seat 62" are advantageously parallel to the axis A and more preferably coaxial with the axis A, and therefore coaxial with the first protrusion 61' and the first seat 61" of the first shape coupling 61 between the first element 51 and the second element 52 of the hub 2. In particular, such first shape coupling 61, second shape coupling 62 have the same shape and size.

[0062] In addition to the first and second form couplings 61 and 62 described above, the elements 51 , 52 and the hub portion 21 of the damper 19 are connected together via fixing means (not shown) such as threaded connections (eg bolts).

[0063] Therefore, the pulley 1 comprises an axial opening 80 configured to allow the insertion and coupling of such a fixing device. Preferably, such axial openings 80 are at least four openings spaced circumferentially around the axis A, more preferably equally spaced one relative to the other.

[0064] In particular, the first element 51 comprises a first section 80 ′ of such an axial opening 80 , the second element 52 comprises a second section 80 ″ of such an axial opening 80 , and the hub portion 21 comprises a third section 80 ′″ of such an axial opening 80 .

[0065] The decoupler assembly 1 further comprises a centering device 85 configured to allow mounting the different elements carried by the hub 2, namely the actuator 35 and the damper 19 if present, in a predefined angular position relative to the hub 2 and therefore to the crankshaft of the vehicle.

[0066] In particular, the centering device 85 comprises a pin 86 which is fixedly carried by one of the parts of the hub 51, 52 and is configured to be accommodated in a corresponding opening 87 realized in the actuator 35, in the other part of the hub 51, 52 and, if present, in the other part of the damper 19.

[0067] In the disclosed embodiment, the pins 86 are two and spaced circumferentially about the axis A at two angularly opposite positions. The openings 87 are implemented in precise positions on the actuator 35 and the damper 19 to allow the actuator 35 and the damper 19 to be mounted in circumferentially predefined positions about the axis A.

[0068] It should also be noted that the damper 19 (when present) is placed at a preset distance X relative to the crankshaft coupling (ie relative to the end of the hub 2 opposite the damper 19).

[0069] In detail, such a preset distance X is greater than 80 mm, preferably greater than 100 mm, in particular 120 mm. In particular, the mass of the damper 19 is comprised within the range between 6 kg and 11 kg at such a preset distance X. In more detail, the inertial mass is 82 kg mm.

[0070] The operation of the pulley 1 according to the above two embodiments is as follows.

[0071] During standard operation of the pulley 1, in a first operating step generally called drive mode and constituting normal operation of the pulley 1, when the drive shaft pulls the accessory, the speed of the hub 2 tends to exceed the speed of the crown 3. To this end, the spokes 36 of the actuator 35 transmit the torque to the lugs 16 with the interposition of the corresponding elastic group 30.

[0072] The above situation occurs symmetrically in the overrunning state, ie when the speed of the crown 3 tends to exceed the speed of the hub 2 .

[0073] Therefore, the advantages of the pulley 1 according to the present innovation are obvious.

[0074] Due to the presence of the centering means, the actuator 35 and the damper 19 can be coupled to the hub at a specific circumferential position, thereby optimizing the damping characteristics of the decoupler.

[0075] Furthermore, the mounting of the separator is improved overall by the presence of a hub realized in different parts which are coupled together via a form coupling and via a centering device.

[0076] Furthermore, since the sealing device 40 is not carried in a seat realized in the hub, but slides on this hub and is carried by the crown, the manufacture of the separator is economical since no dedicated seats or complex mountings are required.

[0077] Furthermore, due to the fact that the first part of the hub is realized with a different harder material / surface treatment, this first part can support heavy loads without the need to realize the entire hub with such material / surface treatment. This saves costs while maintaining good performance.

[0078] Furthermore, due to the unique distance of the damper relative to the crankshaft coupling, its mass can be reduced, resulting in cost savings in manufacturing the decoupler as well as cost savings due to reduced weight, thus facilitating its installation.

[0079] All of the above effects are achieved while maintaining good filtering characteristics of the separator.

[0080] Furthermore, synergistically, all elements contribute to making the overall manufacture of the pulley simple and economical.

[0081] Finally, it is clear that modifications or variations may be made to the pulley described without departing from the scope of protection defined by the claims.

[0082] Firstly, the pulley can be used not only, but not exclusively, for a crankshaft of an internal combustion engine but also for one of the auxiliary components of the internal combustion engine.

[0083] As for the elastic groups 30, they can be implemented in many different ways without modifying their function. For example, they can include springs of different properties or several springs connected in series or in parallel. Nevertheless, the elastic groups can be four, and the spokes of the actuator can also be four.

[0084] The dynamic damper may not be present and the actuator may be carried differently by the hub. Likewise, the roller bearings may be replaced by bushings.

[0085] However, the disclosed seal may be replaced by a device having the same function.

Claims

1. A filter pulley (1), comprising a hub (2), a crown (3), and at least one elastic group (30), wherein the hub (2) is adapted to be fixed to a shaft rotating about an axis (A), the crown (3) is coaxially and freely rotatably mounted on the hub (2), the at least one elastic group (30) is circumferentially arranged relative to the hub (2) and the crown (3), and each of the at least one elastic group (30) is interposed between a pair of first parts (36) fixedly carried by the hub (2) and between a pair of second parts (16) fixedly carried by the crown (3), the filter pulley (1) comprising a dynamic damper (19) carried by the hub (2), characterized in that The dynamic damper (19) is carried at a position with an opposite end distance greater than 80 mm relative to the hub (2).

2. The filter pulley according to claim 1, characterized in that: The dynamic damper (19) has a mass of less than 11 kg.

3. The filter pulley according to claim 1, characterized in that: The wheel hub (2) comprises a first element (51) and a second element (52) connected together by a fixing device.

4. The filter pulley according to claim 3, characterized in that: The second element (52) is configured to be connected to the shaft, and the first component (36) is carried between the first element (51) and the second element (52), or is fixedly carried by one of the first element (51) and the second element (52).

5. The filter pulley according to claim 3, characterized in that: The first element (51) and the second element (52) are connected via a first positive coupling (61).

6. The filter pulley according to claim 5, characterized in that: The first positive coupling (61) comprises a first projection (61') carried in a fixed manner to one between the first element (51) and the second element (52) and a first seat (61") realized in the other between the first element (51) and the second element (52).

7. The filter pulley according to claim 3, characterized in that: The dynamic damper (19) comprises a hub part (21) carried by the first element (51) via a second positive connection (62).

8. The filter pulley according to claim 7, characterized in that: The second positive coupling (62) comprises a second projection (62') carried in a fixed manner to one between the first element (51) and the hub part (21) and a second seat (62") realized in the other between the first element (51) and the hub part (21).

9. The filter pulley according to claim 1, characterized in that: The pair of second parts (16) are protrusions integral with the element (11) of the crown (3).

10. The filter pulley according to claim 1, characterized in that: The at least one elastic group (30) slides circumferentially inside a space (10) formed between the first component (36) and / or the second component (16).

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